You can make use of the ants behavior to help get rid of them, or even use them to help you in productive ways.
As the insect terminators would say, we live in an ant hill. The entire neighborhood sits on hills, with large amount of steep, unbuildable spaces around houses that you don't have access. Even if you get rid of all ants around your property, if your yard is in any way still inhabitable for the ants after the chemicals subside, they will certainly come back. There's an unlimited supply of them.
At first I used to spray all around the house and yard with chemical spray that is attached to the hose, suitable for lawns and plants. It's effective but it doesn't last. Also it's also difficult to isolate yourself from the insecticides. You breath the water vapors with chemicals in it, the vapor blow back by the wind all over you. Then we call in the terminators. It's not any better, because they recommend to spray for you every three month standard. It's not termination. In out area, the standard won't work. Some recommend to spray every other month, using expensive but safer chemicals.
Basically it's a waster of money. When I don't see the ants eye to eye, they don't bother me. Not that they destroy anything significant. When there are two many of them coming to attack everything, I can just spray around. Just 10 min's of work, using a whole bottle of lawn insecticide. And then I went for a decontamination shower.
But I didn't do it anymore. I observed that the ant algorithms are very simple:
* ants only live in hidden dry areas
* ants need water and food
* ants travel in the shortest paths
My new strategy is draw them out, find the colony and kill them all. You don't really need to draw them out. After intense heat wave, they will go out in search of water. After heavy rain, they will move their flooded colony to a new dryer place. When I want to draw them out when I want, I would flood the boundary of the yard or any possible dry spots around the house. Also, dog food pellets are the best bait, never fails, while the ant baits with poisons in hardware stores never work.
Once the ants need to go out, they are very much exposed. They like to travel on flat surfaces without obstacles, even if they are exposed out in the open, under intense heat and sunlight. They don't like to travel across plants or soil, which are obstacle courses compared to flat stones or concrete. So if you fill any gaps in your stone or concrete pathway with paving sand for example, the ants will certainly march along the surface of the pathway.
Other favorite places where ants like to travel are fences, the outdoor damp prove course several inches above base level of the house.
Ants are easy to find in these areas in plain sight. They just don't like to hide under grass or ground cover. Follow the line and you know where their colonies are.
To kill them I use a hand operated spray, with chemicals that can be used on fruits. It doesn't take much spray to flood their colony with insecticides. And if you like, you can spray on the whole line of ants sometimes a 100 feet long, often made up of most of the colony.
The ants come because there's some food. It's time to harvest the fruits before the ants. Or your sprinklers do not cover all the lawn, with some dry spots. Or you have some cracks outside the house, allowing the ants to get in for a cool dry shelter. Without ants, these spots are hard to find. Ants are just so useful!
Thursday, September 27, 2007
Tuesday, September 25, 2007
Mexican Drip Irrigation
My house has a standard 1/2 irrigation system. However, the previous owner must had designed the layout and laid the pipes himself. Nothing is right. Grass is supposed to grow right up to the edge of the house and the fences. It is extremely difficult to cover all the areas to be watered.
But that doesn't bother my gardener. He adjusted all the sprinklers so that all green things are covered. He doesn't care how much water is wasted. He doesn't care about water damage to the stucco. Those are not his problems. I changed new quality spray heads and adjust the spraying distance without success.
Out of frustration I changed to drip irrigation gradually. Initially it looked good. Though the 1/2 underground pipes are fixed, I can now place 1/4 tubes over the ground wherever I wanted, so the tiny, precise spray heads are right next to the plants. Can't do anything about the standard pop-up sprinklers, but with the help of fixed drip irrigation spray heads, I can cover grass that the pop-ups cannot.
The problem is, the 1/4 adapters got blown off by the water pressure, or the spray heads got blown off. But I cannot install a pressure reducer that is usual for drip irrigation. My system is mixed. Though this could be done if I change over completely. Luckily I didn't. Silly me. Recently, when I replaced the shut-off valve to the yard, I discovered that my pressure regulator deals with water to my house only. All other water are not regulated.
So my irrigation system was at over 100 psi. No matter the electric valves cannot be adjusted and so short lived. No matter something burst all the time. No matter all the sprinklers and spray heads seem to be out of control with water spraying everything. No matter it was so difficult to adjust the volume of everything. No matter that when something was wrong with my neighbor's swimming pool plumbing, we both burst some sprinklers together.
The major problem was my gardener, his successors, and their whole team members. When they clear weeds they will clear the over ground 1/4 tubes too. Or they will cut the spray heads off without knowing. It's not surprising because often they destroy indestructible pop-up sprinklers with their mowers.
Gradually I moved back to a standard 1/2 system, leaving nothing over ground to be destroyed. My 1/4 system resigned to the garage.
Until recently it dawned on me that I was visiting the wrong department for drip irrigation. I used to get everything from the garden center - the 1/2 to 1/4 adapters, the tubes, the spray heads, the connectors. Either they are too tough to join together, or too easy to connect but will be immediately blown off when water pressure is applied.
I also used the standard plumbing department for 1/2 tubes and connectors. I tried to add something rigid, like splitting one outlet into two, before converting it to 1/4 at the end, which is much less rigid.
It suddenly dawned on me that the ice making, 1/4 tubing department, that I visited many times for my reverse osmosis system, are compatible with the 1/4 drip irrigations. I never realized that the drip irrigation uses standard 1/4 tubes. That made a lot of difference.
Now instead of the T's and couplers from hell, I just use quick connect. It's a few dollars a piece but saving my fingers is priceless. The 1/2 to 1/4 adapters are industrial strength, not plastic toys as from the drip department. Now designing and installing the system is a joy.
Now I have more tricks to fix the system in place. In the past I rely on stakes to hold the tubes and spray heads. Now I can use rigid 1/4 tubes as far as I can. In the past my stakes get bigger and bigger so as to survive the onslaught of my gardeners and their teams. Now I use custom made acrylic pieces to hold the tubes and spray heads, and glue or screw the whole thing to something rigid. As the acrylic is crystal clear. The whole thing can look good or not visible at all.
One final thing. All spray heads are directly pushed or screwed into the end of tube directly. I will now only use the screw ones which is easier. And before screwing them into the tubes, I apply some gorilla glue. In the past you can hardly reuse the spray head this way. Now all the spray heads are mostly attached to half an inch of tube, to be pushed effortlessly into quick connectors.
Now I can add something, change the spray heads, replace damaged materials fast. Don't know why don't sell it that way, instead of in 3 separate areas of the plumbing department.
But that doesn't bother my gardener. He adjusted all the sprinklers so that all green things are covered. He doesn't care how much water is wasted. He doesn't care about water damage to the stucco. Those are not his problems. I changed new quality spray heads and adjust the spraying distance without success.
Out of frustration I changed to drip irrigation gradually. Initially it looked good. Though the 1/2 underground pipes are fixed, I can now place 1/4 tubes over the ground wherever I wanted, so the tiny, precise spray heads are right next to the plants. Can't do anything about the standard pop-up sprinklers, but with the help of fixed drip irrigation spray heads, I can cover grass that the pop-ups cannot.
The problem is, the 1/4 adapters got blown off by the water pressure, or the spray heads got blown off. But I cannot install a pressure reducer that is usual for drip irrigation. My system is mixed. Though this could be done if I change over completely. Luckily I didn't. Silly me. Recently, when I replaced the shut-off valve to the yard, I discovered that my pressure regulator deals with water to my house only. All other water are not regulated.
So my irrigation system was at over 100 psi. No matter the electric valves cannot be adjusted and so short lived. No matter something burst all the time. No matter all the sprinklers and spray heads seem to be out of control with water spraying everything. No matter it was so difficult to adjust the volume of everything. No matter that when something was wrong with my neighbor's swimming pool plumbing, we both burst some sprinklers together.
The major problem was my gardener, his successors, and their whole team members. When they clear weeds they will clear the over ground 1/4 tubes too. Or they will cut the spray heads off without knowing. It's not surprising because often they destroy indestructible pop-up sprinklers with their mowers.
Gradually I moved back to a standard 1/2 system, leaving nothing over ground to be destroyed. My 1/4 system resigned to the garage.
Until recently it dawned on me that I was visiting the wrong department for drip irrigation. I used to get everything from the garden center - the 1/2 to 1/4 adapters, the tubes, the spray heads, the connectors. Either they are too tough to join together, or too easy to connect but will be immediately blown off when water pressure is applied.
I also used the standard plumbing department for 1/2 tubes and connectors. I tried to add something rigid, like splitting one outlet into two, before converting it to 1/4 at the end, which is much less rigid.
It suddenly dawned on me that the ice making, 1/4 tubing department, that I visited many times for my reverse osmosis system, are compatible with the 1/4 drip irrigations. I never realized that the drip irrigation uses standard 1/4 tubes. That made a lot of difference.
Now instead of the T's and couplers from hell, I just use quick connect. It's a few dollars a piece but saving my fingers is priceless. The 1/2 to 1/4 adapters are industrial strength, not plastic toys as from the drip department. Now designing and installing the system is a joy.
Now I have more tricks to fix the system in place. In the past I rely on stakes to hold the tubes and spray heads. Now I can use rigid 1/4 tubes as far as I can. In the past my stakes get bigger and bigger so as to survive the onslaught of my gardeners and their teams. Now I use custom made acrylic pieces to hold the tubes and spray heads, and glue or screw the whole thing to something rigid. As the acrylic is crystal clear. The whole thing can look good or not visible at all.
One final thing. All spray heads are directly pushed or screwed into the end of tube directly. I will now only use the screw ones which is easier. And before screwing them into the tubes, I apply some gorilla glue. In the past you can hardly reuse the spray head this way. Now all the spray heads are mostly attached to half an inch of tube, to be pushed effortlessly into quick connectors.
Now I can add something, change the spray heads, replace damaged materials fast. Don't know why don't sell it that way, instead of in 3 separate areas of the plumbing department.
Saturday, September 22, 2007
Scam: reverse osmosis permeate pump and valve
Not exactly scam, but depends on who and how they sell it. The permeate pump is certified, made of harmless material, and won't fall apart, but it is the magic bullet as claimed in the manufacturer's Aquatec website? No. But since they only sell it to distributors, they give you no specification and they are not responsible how you use it. But now these companies know that nothing can stop people selling things to individuals on eBay, they are a bit careful on their website, in order not to develop a scandal.
Many pumps are sold to retrofit existing systems. But notice the 75 psi feed input on the main diagram on their website. If you haven't got that pressure, it very doubtful it will work well. And if you got all that pressure, it's doubtful if you need a pump to get good results.
Standard main water pressure depends on water district, but should be 50 psi, which is the value for sprinkler specification. You may get higher pressure if you live uphills in individual houses, where the water pressure gradually decrease downhills to 50 psi for houses at the bottom. In this case you need a pressure regulator, which is usually factory preset to 50 to 60 psi, with 75 psi as the absolute rating. So basically, now that the permeate pump isn't new anymore, Aquatec is basically saying you need a booster pump without admitting it. A booster pump cost twice as much and gives you a lot of improvement if your feed is just 50 psi. It's crazy if you use a booster pump plus a permeate pump. Since I have 75 psi without the need for a booster pump, I'm OK. It wouldn't work well for 60 psi, and I can prove it.
When the tank is empty, that is, no back pressure to the membrane, the membrane sees the full pressure of about 70 psi. The pump is supposed to maintain the back pressure to at most a few psi so the full 70 psi pressure is maintained at all times. With the right flow restrictor, there should be enough pressure and flow in the brine/concentrate to do that. But I found out that the recovery rate have to be high at about 25%. Which means that the drinking water to waste water ratio is 1:3. This is far from the usual 1:4, or 20%, and far from the specified Filmtec membrane recovery of 15%.
But all is not lost. At 70 psi, even 25% recovery gives 98% stable rejection, which is the same specified rejection at 50 psi and 15% recovery. So with a virtual booster pump, and a permeate pump, I can't get better rejection but I waste half the water, 1:3 recovery instead of 1:6 recovery.
It won't work if you don't have 75 psi main feed. Say at 60 psi feed, you have about 50 psi across the membrane, and clearly at this pressure, you need 15% recovery to achieve anywhere near 98% rejection. 25% recovery is far off.
It's doubtful if you need any pump when you have 75 psi pressure. A 75 gpd membrane becomes 110 gpd which is a hell lot of water. But since the pressure is constant across the membrane, it's easy to design your system, and the performance is guaranteed under all circumstances. In other words, peace of mind.
In pumpless systems, basically the water is excellent when the tank is empty. Then the water tend to get worse as the tank fills up, or you waste a lot more water without realizing it, that's what Aquatec is trying to market their pumps. With typical usage, the system works most often when only a few cup or a kettle of water is being drawn from the tank. The water is worse or wasting most water when the pressure across the membrane is often 50% to 33% of an empty tank.
Actually I would like to write software to design residential systems. Dow has free software but far too complex and did not give out parameters for the residential membranes. So I couldn't do anything but to use 75 psi main pressure. The pressure is constant and everything is constant so it's easy to design.
And now the cutoff valve. It's not cheap at 1/3 of the pump price. But does it worth it? Nobody claims that it's necessary but say enough that you will buy it. I was surprised to find out that the valve don't cutoff at 90%, but about the same as the old valves about 66%. I talked to the distributors and manufacturer and it seems that they are well prepared. The distributor send me over to the manufacturer, who promise to test it and replace it if it's defective. But I am not to expect 90%, but 85% depending on pressure.
I almost sent it off when I realized that now the cutoff pressure of my tank will be the main pressure of most people, at 50 psi. It will be crazy to increase that to 65 psi. I don't need that and the pump may not work at that pressure. Also, the valve turn back on at 30 psi, giving 20 psi of hysteresis so the system won't turn on and off whenever people drawn a glass of water or a kettle of water. I don't know if my old valve do that. But since the new valve has JG connectors that are easy for me to measure things, and that the tubings are fitted already, I rather not go back to the old one.
Previously I have doubts about measuring pressure when water is flowing. But I find that it's very accurate, the dynamic pressure into the tank equals exactly the static pressure when the tank is isolated. After all, what else can it be? Now I left the pressure gauge dangling in a T piece somewhere in the water path. And since I needed a tank shutoff valve as an adapter for the standard gauge, I can shut off the valve so the gauge isn't in contact with potable water when not in use.
Many pumps are sold to retrofit existing systems. But notice the 75 psi feed input on the main diagram on their website. If you haven't got that pressure, it very doubtful it will work well. And if you got all that pressure, it's doubtful if you need a pump to get good results.
Standard main water pressure depends on water district, but should be 50 psi, which is the value for sprinkler specification. You may get higher pressure if you live uphills in individual houses, where the water pressure gradually decrease downhills to 50 psi for houses at the bottom. In this case you need a pressure regulator, which is usually factory preset to 50 to 60 psi, with 75 psi as the absolute rating. So basically, now that the permeate pump isn't new anymore, Aquatec is basically saying you need a booster pump without admitting it. A booster pump cost twice as much and gives you a lot of improvement if your feed is just 50 psi. It's crazy if you use a booster pump plus a permeate pump. Since I have 75 psi without the need for a booster pump, I'm OK. It wouldn't work well for 60 psi, and I can prove it.
When the tank is empty, that is, no back pressure to the membrane, the membrane sees the full pressure of about 70 psi. The pump is supposed to maintain the back pressure to at most a few psi so the full 70 psi pressure is maintained at all times. With the right flow restrictor, there should be enough pressure and flow in the brine/concentrate to do that. But I found out that the recovery rate have to be high at about 25%. Which means that the drinking water to waste water ratio is 1:3. This is far from the usual 1:4, or 20%, and far from the specified Filmtec membrane recovery of 15%.
But all is not lost. At 70 psi, even 25% recovery gives 98% stable rejection, which is the same specified rejection at 50 psi and 15% recovery. So with a virtual booster pump, and a permeate pump, I can't get better rejection but I waste half the water, 1:3 recovery instead of 1:6 recovery.
It won't work if you don't have 75 psi main feed. Say at 60 psi feed, you have about 50 psi across the membrane, and clearly at this pressure, you need 15% recovery to achieve anywhere near 98% rejection. 25% recovery is far off.
It's doubtful if you need any pump when you have 75 psi pressure. A 75 gpd membrane becomes 110 gpd which is a hell lot of water. But since the pressure is constant across the membrane, it's easy to design your system, and the performance is guaranteed under all circumstances. In other words, peace of mind.
In pumpless systems, basically the water is excellent when the tank is empty. Then the water tend to get worse as the tank fills up, or you waste a lot more water without realizing it, that's what Aquatec is trying to market their pumps. With typical usage, the system works most often when only a few cup or a kettle of water is being drawn from the tank. The water is worse or wasting most water when the pressure across the membrane is often 50% to 33% of an empty tank.
Actually I would like to write software to design residential systems. Dow has free software but far too complex and did not give out parameters for the residential membranes. So I couldn't do anything but to use 75 psi main pressure. The pressure is constant and everything is constant so it's easy to design.
And now the cutoff valve. It's not cheap at 1/3 of the pump price. But does it worth it? Nobody claims that it's necessary but say enough that you will buy it. I was surprised to find out that the valve don't cutoff at 90%, but about the same as the old valves about 66%. I talked to the distributors and manufacturer and it seems that they are well prepared. The distributor send me over to the manufacturer, who promise to test it and replace it if it's defective. But I am not to expect 90%, but 85% depending on pressure.
I almost sent it off when I realized that now the cutoff pressure of my tank will be the main pressure of most people, at 50 psi. It will be crazy to increase that to 65 psi. I don't need that and the pump may not work at that pressure. Also, the valve turn back on at 30 psi, giving 20 psi of hysteresis so the system won't turn on and off whenever people drawn a glass of water or a kettle of water. I don't know if my old valve do that. But since the new valve has JG connectors that are easy for me to measure things, and that the tubings are fitted already, I rather not go back to the old one.
Previously I have doubts about measuring pressure when water is flowing. But I find that it's very accurate, the dynamic pressure into the tank equals exactly the static pressure when the tank is isolated. After all, what else can it be? Now I left the pressure gauge dangling in a T piece somewhere in the water path. And since I needed a tank shutoff valve as an adapter for the standard gauge, I can shut off the valve so the gauge isn't in contact with potable water when not in use.
Friday, September 14, 2007
Camping tech
Most CA state camp grounds have free Wi-Fi access. It's a simple thing to do but made me think of an unrelated question: can we be modern nomads? For the rules, state parks usually have 1 or 2 week maximum stay per camp site, 1 month max stay per year within a county. It's not much but there are local sites that do not belong to the states, and there are federal sites. And there are 52 states!
But would you do that? Kids need to go to school, and that's that. Though home schooled kids aren't that rare, so moving every other week may not be too bad.
I love outdoors. Half a lifetime ago, space was so precious that I rather go camping when I could, even in tropically wet weather, walking for hours with all equipment on my shoulders. Tents weren't even draft and water proof.
I touched a tent again a couple of years ago. I saw one small and cheap on sale and picked it up for earthquake preparation. And forgot about it.
It turns out that Rangers looking after the camp sites have rather dangerous jobs. For popular beaches near urban centers, there's the drunks. Now for remote sites, they often go into heavy gun fights with the pot growers, with millions worth of pots at sake. Other than those, crimes usually aren't premeditated. You don't plan to rob somebody random in remote areas. Without premeditation, it's hard to get away with it, such as the Yosemite killings. For the good part, no where else in the world you get to live in a free gated community, with armed guards until 10 pm, then total lock down until dawn. Here I bet criminals can't run, they can only drive. I doubt if anyone will try to do the hard work when they can't get in or get away with a car.
Tasers are going to be very affordable, may be as popular as pepper sprays. You can also draw up visible and invisible boundaries with infrared, laser and lots of cams. But for the moment, camping is still a very much friendly family affair. The rangers will check you up at least twice a day. When the sites aren't too busy, they will remember you if your clean car looks out of place, thinking that you are newbies and needs extra attention. Sites owned by rich counties are even better.
The bad thing about camping in CA is that you are basically living on dirt. You don't have a lawn if you don't have sprinklers, unless you camp by the river. But most "rivers" dries up in summer, while winter is too cold. So you have to have tents for bed rooms, that you only get in for sleeping, when you are presumably clean. You need separate living spaces, sheltered from the sun, and preferably from insects. You also need changing rooms too. You don't want to walk in and out of bedrooms with feet full of dirt. You also don't want to kick everybody out of the living rooms just to change into some special gear, such as swim suit. And for the beaches, you need to bring a cabana to the water front.
Modern materials are amazing. My cheap made in China tents and canopies has very light flexible support poles, wafer thin fabric. But still I couldn't manage to make a hole in anything. All zippers are still working. The fine insect screen didn't break at all even after attacked all night by raccoons. I can carry all the "rooms" easily in my trunk, and I can erect huge canopies alone.
That's why I don't fancy RV's. It's two cramped in comparison.
As for creature comfort, you are spoiled for choice in chairs and beds, king size down to twin, high tech air bed, or self inflated. Satellite TV dish are portable. If you don't like the free WiFi access, there's the true satellite broadband service. Food is always great, briquettes are always better than gas grill back home. The match lighted ones are as convenient as butane gas.
Now the dreaded loo. Public showers aren't that bad. Typically hot showers are coin operated with a large gas boiler, giving decent pressure and volume. If you are fuzzy you can bring your own shower tent. With solar heating and battery pumps, a private shower room can be barely decent. Of course RV's all got these, and with electricity hookups, RV's can afford decent heaters and powerful pumps.
The public toilets are very clean, but only in the morning right after they cleaned it. At busy seasons it's terrible after an hour or two, even though most campers try to minimize their mess. Imagine McDonald only clean it's toilets once a day! Some more remote places are called environmental sites, where there are only so called chemical toilets. Terrible! terrible! I would rather die of blocking.
RV seems to be a lot better with it's own toilet. You still need to deal with the mess but it's your own toilet and your own mess.
But not anymore. It must be fairly new, because the majority of toilets for sale are till big buckets. You store your mess in it, may be put some fragrance in it after every use, and god knows how you empty that and clean that afterward.
Now there are high absorbency powder to turn liquid waste into jelly, and semi solid waste will become more solid with odor reduced. Instead of a bucket, you empty into a toilet seat with big plastic bags underneath. Whenever you want, you seal the plastic bag with another, throwing the whole thing into trash. I suppose the concept isn't that new. But now all the materials are biodegradable, the water tight plastic bags degenerates within 6 months. It was approved by everybody, endorsed by me. Now a toilet/shower tent is lighter than a typical camping chair. You can have your out house wherever you want, with a view if you want. The worst nightmare becomes a joy. RV's aren't that good. There's totally no mess to deal with. The plastic bags aren't cheap, but I'll still go for it if they sell it like crack.
Maybe someday dry toilets are the way to go back home. The flush toilet has been haled as a great invention, but may be a big mistake. Dry toilets do not waste water. A out house in the yard is no problem at all. You can have one for each in the family if you want. For apartments you can have ventilation rooms, which are easier to build than conventional toilets. Perhaps doing it in a slightly larger closet is good. Houses can be smaller without the toilets, and it's simpler without all the plumbings.
But would you do that? Kids need to go to school, and that's that. Though home schooled kids aren't that rare, so moving every other week may not be too bad.
I love outdoors. Half a lifetime ago, space was so precious that I rather go camping when I could, even in tropically wet weather, walking for hours with all equipment on my shoulders. Tents weren't even draft and water proof.
I touched a tent again a couple of years ago. I saw one small and cheap on sale and picked it up for earthquake preparation. And forgot about it.
It turns out that Rangers looking after the camp sites have rather dangerous jobs. For popular beaches near urban centers, there's the drunks. Now for remote sites, they often go into heavy gun fights with the pot growers, with millions worth of pots at sake. Other than those, crimes usually aren't premeditated. You don't plan to rob somebody random in remote areas. Without premeditation, it's hard to get away with it, such as the Yosemite killings. For the good part, no where else in the world you get to live in a free gated community, with armed guards until 10 pm, then total lock down until dawn. Here I bet criminals can't run, they can only drive. I doubt if anyone will try to do the hard work when they can't get in or get away with a car.
Tasers are going to be very affordable, may be as popular as pepper sprays. You can also draw up visible and invisible boundaries with infrared, laser and lots of cams. But for the moment, camping is still a very much friendly family affair. The rangers will check you up at least twice a day. When the sites aren't too busy, they will remember you if your clean car looks out of place, thinking that you are newbies and needs extra attention. Sites owned by rich counties are even better.
The bad thing about camping in CA is that you are basically living on dirt. You don't have a lawn if you don't have sprinklers, unless you camp by the river. But most "rivers" dries up in summer, while winter is too cold. So you have to have tents for bed rooms, that you only get in for sleeping, when you are presumably clean. You need separate living spaces, sheltered from the sun, and preferably from insects. You also need changing rooms too. You don't want to walk in and out of bedrooms with feet full of dirt. You also don't want to kick everybody out of the living rooms just to change into some special gear, such as swim suit. And for the beaches, you need to bring a cabana to the water front.
Modern materials are amazing. My cheap made in China tents and canopies has very light flexible support poles, wafer thin fabric. But still I couldn't manage to make a hole in anything. All zippers are still working. The fine insect screen didn't break at all even after attacked all night by raccoons. I can carry all the "rooms" easily in my trunk, and I can erect huge canopies alone.
That's why I don't fancy RV's. It's two cramped in comparison.
As for creature comfort, you are spoiled for choice in chairs and beds, king size down to twin, high tech air bed, or self inflated. Satellite TV dish are portable. If you don't like the free WiFi access, there's the true satellite broadband service. Food is always great, briquettes are always better than gas grill back home. The match lighted ones are as convenient as butane gas.
Now the dreaded loo. Public showers aren't that bad. Typically hot showers are coin operated with a large gas boiler, giving decent pressure and volume. If you are fuzzy you can bring your own shower tent. With solar heating and battery pumps, a private shower room can be barely decent. Of course RV's all got these, and with electricity hookups, RV's can afford decent heaters and powerful pumps.
The public toilets are very clean, but only in the morning right after they cleaned it. At busy seasons it's terrible after an hour or two, even though most campers try to minimize their mess. Imagine McDonald only clean it's toilets once a day! Some more remote places are called environmental sites, where there are only so called chemical toilets. Terrible! terrible! I would rather die of blocking.
RV seems to be a lot better with it's own toilet. You still need to deal with the mess but it's your own toilet and your own mess.
But not anymore. It must be fairly new, because the majority of toilets for sale are till big buckets. You store your mess in it, may be put some fragrance in it after every use, and god knows how you empty that and clean that afterward.
Now there are high absorbency powder to turn liquid waste into jelly, and semi solid waste will become more solid with odor reduced. Instead of a bucket, you empty into a toilet seat with big plastic bags underneath. Whenever you want, you seal the plastic bag with another, throwing the whole thing into trash. I suppose the concept isn't that new. But now all the materials are biodegradable, the water tight plastic bags degenerates within 6 months. It was approved by everybody, endorsed by me. Now a toilet/shower tent is lighter than a typical camping chair. You can have your out house wherever you want, with a view if you want. The worst nightmare becomes a joy. RV's aren't that good. There's totally no mess to deal with. The plastic bags aren't cheap, but I'll still go for it if they sell it like crack.
Maybe someday dry toilets are the way to go back home. The flush toilet has been haled as a great invention, but may be a big mistake. Dry toilets do not waste water. A out house in the yard is no problem at all. You can have one for each in the family if you want. For apartments you can have ventilation rooms, which are easier to build than conventional toilets. Perhaps doing it in a slightly larger closet is good. Houses can be smaller without the toilets, and it's simpler without all the plumbings.
Wednesday, September 12, 2007
The perfect geek material
I never like wood, but I thought it was the only material that you can custom in your garage. Over the years I have a circular saw to cut 2"x4" beams for play things, now the saw is being recalled. I also have a little power sander to smooth the coarse wood so as for the surface not to be too tough for the touch. I once brought a jigsaw to build a custom corner table. I thought it was good but it got thrown away. An fake antique table replaced it.
I was looking for something to replace the cardbox in the yard, when I come across acrylic. I thought it was perfect. It's look like glass, lighter but tougher. And you can cut it to size with a knife. Perfect, just what I needed. So I designed a rather complicated box with lots of compartments, doors and openings in it, using a free CAD package.
I fit my design into a 2'x4' flat piece of acrylic at 1/8" thick. When the piece comes, it was perfect. It really looks good, crystal clear. It was protected by plastic film so you cannot scratch it while cutting it. The thickness is just right. It's just tough for you to build a strong box. Any thicker cost a lot more, and any thinner it feels plastic instead of glass. But there's one catch. There's no way you can cut it with a knife, at least not a decent long edge.
So I brought out my jigsaw. It's tough work. It's very slow to cut through the acrylic compared to wood that is a lot thicker, which is expected. Also, you cannot make a straight cut with a jigsaw, unless you have a decent work bench, which I don't. I should have ordered custom cutting which is more expensive than the material itself. At least for the long cuts, I should use some help. But I soldiered on.
The good thing is that, at a right saw speed, the blade create just enough heat to melt through the acrylic, but not too much melting, giving a nice smooth edge. The saw dust are basically acrylic melted into tiny beads. It's everywhere but a lot more pleasant than wood dust and it's much easy to clean.
The bad - the unexpected jigsaw instead of a knife leaves me with rectangles big and small, all without straight edges and right angles! I know it would be a challenge to fit the pieces together. Also, the dimensions are more than 1/8" off after cutting. So I have to run through the CAD package to made alterations as I went along.
Luckily I brought some small right angled wedges to help to glue the pieces together at the corner, and some squared tubes to help with the squareness of my box. And I settled for some toxic solvents for a quick welding of the pieces, instead of using slow solvents and requiring clamps that I don't have, and don't know how to apply in small spaces.
You can imagine the final box is comparable to a cardboard box using coarse tapes to stick the pieces together. But acrylic is something. You can see the glue, it's clear but there are bubbles in it. It's hard not to use excessive glue for the uneven pieces. It drys hard and visible, but it's as clear as the acrylic. Basically it's just acrylic melted and reformed. The wedges at the corners are ugly, no sides are straight and barely square. No edges are smooth.
But the whole junk is rather addictive to look at. It's my junk and it's like glass suspending in glass. You got to enjoy the fine details, like uneven application of the glues on the edges and hinges. The curved edges, and the blurred edges just like glass. Best of all, it's tough and highly functional. If I order custom cutting for the large pieces, or invest in a bench saw, it would be perfect the 2nd time round.
I can imagine 1/16" thick sheets will be perfect for delicate things, such as custom electronic enclosures. You should be able to cut it accurately using knifes. Polish the edges and use thin glues that make perfect invisible joints. You can drill small accurate holes, or cut out large portions for a screen mount etc. You can order custom laser cutting for you name to stick on it too.
The major problem I had was needing a lot of motors with gearboxes to mount on my beautiful junk. It's just too expensive compared to the whole box, and looked ugly. You can get bare motors a lot cheaper, compact and powerful. But without gears and crank arms they are useless. So after exhausting the web to find something suitable, I cut a little piece of acrylic as the crank arm and drill a hole in it. I put the bare motor shaft in it and glue them together using gorilla glue. It surprised me that now it's a very tough crank arm! The rest of the problem is mounting the motor onto the box. It just need another small piece and screws to clamp the motor securely in place. Now even the motor mount and the crank arm are transparent and look good, with screw suspending in mid air.
I fell in love.
I was looking for something to replace the cardbox in the yard, when I come across acrylic. I thought it was perfect. It's look like glass, lighter but tougher. And you can cut it to size with a knife. Perfect, just what I needed. So I designed a rather complicated box with lots of compartments, doors and openings in it, using a free CAD package.
I fit my design into a 2'x4' flat piece of acrylic at 1/8" thick. When the piece comes, it was perfect. It really looks good, crystal clear. It was protected by plastic film so you cannot scratch it while cutting it. The thickness is just right. It's just tough for you to build a strong box. Any thicker cost a lot more, and any thinner it feels plastic instead of glass. But there's one catch. There's no way you can cut it with a knife, at least not a decent long edge.
So I brought out my jigsaw. It's tough work. It's very slow to cut through the acrylic compared to wood that is a lot thicker, which is expected. Also, you cannot make a straight cut with a jigsaw, unless you have a decent work bench, which I don't. I should have ordered custom cutting which is more expensive than the material itself. At least for the long cuts, I should use some help. But I soldiered on.
The good thing is that, at a right saw speed, the blade create just enough heat to melt through the acrylic, but not too much melting, giving a nice smooth edge. The saw dust are basically acrylic melted into tiny beads. It's everywhere but a lot more pleasant than wood dust and it's much easy to clean.
The bad - the unexpected jigsaw instead of a knife leaves me with rectangles big and small, all without straight edges and right angles! I know it would be a challenge to fit the pieces together. Also, the dimensions are more than 1/8" off after cutting. So I have to run through the CAD package to made alterations as I went along.
Luckily I brought some small right angled wedges to help to glue the pieces together at the corner, and some squared tubes to help with the squareness of my box. And I settled for some toxic solvents for a quick welding of the pieces, instead of using slow solvents and requiring clamps that I don't have, and don't know how to apply in small spaces.
You can imagine the final box is comparable to a cardboard box using coarse tapes to stick the pieces together. But acrylic is something. You can see the glue, it's clear but there are bubbles in it. It's hard not to use excessive glue for the uneven pieces. It drys hard and visible, but it's as clear as the acrylic. Basically it's just acrylic melted and reformed. The wedges at the corners are ugly, no sides are straight and barely square. No edges are smooth.
But the whole junk is rather addictive to look at. It's my junk and it's like glass suspending in glass. You got to enjoy the fine details, like uneven application of the glues on the edges and hinges. The curved edges, and the blurred edges just like glass. Best of all, it's tough and highly functional. If I order custom cutting for the large pieces, or invest in a bench saw, it would be perfect the 2nd time round.
I can imagine 1/16" thick sheets will be perfect for delicate things, such as custom electronic enclosures. You should be able to cut it accurately using knifes. Polish the edges and use thin glues that make perfect invisible joints. You can drill small accurate holes, or cut out large portions for a screen mount etc. You can order custom laser cutting for you name to stick on it too.
The major problem I had was needing a lot of motors with gearboxes to mount on my beautiful junk. It's just too expensive compared to the whole box, and looked ugly. You can get bare motors a lot cheaper, compact and powerful. But without gears and crank arms they are useless. So after exhausting the web to find something suitable, I cut a little piece of acrylic as the crank arm and drill a hole in it. I put the bare motor shaft in it and glue them together using gorilla glue. It surprised me that now it's a very tough crank arm! The rest of the problem is mounting the motor onto the box. It just need another small piece and screws to clamp the motor securely in place. Now even the motor mount and the crank arm are transparent and look good, with screw suspending in mid air.
I fell in love.
Prototyping down memory lane
It is also a story of what can go wrong went wrong.
Remember I needed some basic electronics for a useful purpose. So I went ahead to design and build a circuit. I want it to be battery or DC adapter operated, it's also a battery backup and charger. The backup and charger part turns out to be rather complicated, which explains my chargers are so bad. I can use lithium batteries and make use of a single chip to do all I wanted, but the chip is used for cell phones, surface mount with no leads, only tiny pads under the chip. No way I can deal with that by hand. So I give that up for the moment and the circuit is strictly Either battery OR DC adapter.
I actually never build much circuits. The kits on sale are rather tame. If they are any good they would design consumer products. Also, you just learn soldering if you build those. I did build something important once with a lot of chips with wrapping tools. With low power you need low noise, together with surface mount components, wire wrapping are way out of fashion. I hate using solderless prototyping boards. I don't need to test everything first. And it's too expensive to use the boards as the final product.
However, once upon a time copper becomes previous metal. So the prototyping boards with lots of copper strips disappeared. The best I can find is some rather expensive boards with just holes on it and a solder tag around it. (But somehow the PCBs plated with coppers are still around, but I have no patient for the slow turn around of making PCBs). I made the mistake of trying it assuming the lack of rails is no big deal.
Firstly, the real time clock and alarm I ripped off from a timer switch is too good, it worked on 1V instead of 3V on my circuit. I knew about it but I thought CMOS would work with wide voltages but not for that clock. So I added another battery to supply the clock and added a transistor to pull up the alarm signal up to 3V.
I chose components to minimize chip and connection count. But the choice of components off the shelf is limited. More importantly, I misread an unimportant part of my own circuit, the gates are to be repeated on all signals in the bus, but I allocated components and space just for one signal. So I have no chips or no space for all the signals. But I can live with that for a prototype.
Without ground and supply rails, the soldering is a nightmare. Every connection is by a wire, and I didn't have the magnet wires, insulated wires with coating that melts when soldered. So I have to strip every wire before soldering using a blunt, large soldering iron. When I brought the iron, I wanted one that is powerful enough to for thick electrical repairs, and also doubles for electronic work if I ever needed. So the tip always touch two chip leads when soldering. It's a nightmare. But I soldered on hoping to get out of hell as soon as possible.
At the end it was spaghettis over and under a plate in 3-D. It was hell. Worse, nothing works that surprised me. The IO drivers all don't work so I don't know what's going on. And I have only a hand held multimeter to trouble shoot. Funny that the main fault was laughable. I used CMOS design for the first time as my real circuit needed to be low powered. The basic quad NAND gates have different pin outs with the TTL versions!!! Just 1 in the 4 gates have different pin outs, but just enough to make everything not working. I vaguely remember that it was to differentiate that it is CMOS rather than TTL. But nowadays you will use the same pinouts, even if it cost you more to manufacturer. But now the CMOS pinout is history and you have to remain compatible.
And since the circuit was a hopeless mess of spaghettis, I had to find another fresh circuit board to start over. Luckily I found an ancient copper stripped board in my garage just enough to fit the chips that I have. It now looks better but still a lot of spaghettis, but less painful to build.
The circuit at least work as expected but a lot of strange happenings, like on and off of motors and LED's when not expected. The power on reset doesn't work as the microprocessor in the real time clock takes a few seconds to reset, while my own circuit resets for a much shorter time. Now it's a random start, but since I cut down the number of states due to insufficient space and chips, it's only head and tails.
The manual reset doesn't work either. I suppose the pull-up resistor is too large to save current. But I can always reset by touching the contact with a wire connected to ground or supply.
The unexpected on and off is due to a long alarm signal. I have a timer circuit to control the
width of the pulse, and to isolated the alarm signal once activated. But I got it wrong assuming it's trivial. So I have to indulge into some Boolean math to arrive at an asynchronous finite state circuit with minimum gates, which have to be a modern classic. But I needed 3 NAND gates. So instead of blinking LED's to save current, some are not blinking to save some gates for the modern classic.
It's working now for weeks on two AA batteries. But very recently I found out that the sparks of a small motor nearby will cause the circuit to change state for certain. It's no big deal as I have to redesign the whole thing anyway.
Remember I needed some basic electronics for a useful purpose. So I went ahead to design and build a circuit. I want it to be battery or DC adapter operated, it's also a battery backup and charger. The backup and charger part turns out to be rather complicated, which explains my chargers are so bad. I can use lithium batteries and make use of a single chip to do all I wanted, but the chip is used for cell phones, surface mount with no leads, only tiny pads under the chip. No way I can deal with that by hand. So I give that up for the moment and the circuit is strictly Either battery OR DC adapter.
I actually never build much circuits. The kits on sale are rather tame. If they are any good they would design consumer products. Also, you just learn soldering if you build those. I did build something important once with a lot of chips with wrapping tools. With low power you need low noise, together with surface mount components, wire wrapping are way out of fashion. I hate using solderless prototyping boards. I don't need to test everything first. And it's too expensive to use the boards as the final product.
However, once upon a time copper becomes previous metal. So the prototyping boards with lots of copper strips disappeared. The best I can find is some rather expensive boards with just holes on it and a solder tag around it. (But somehow the PCBs plated with coppers are still around, but I have no patient for the slow turn around of making PCBs). I made the mistake of trying it assuming the lack of rails is no big deal.
Firstly, the real time clock and alarm I ripped off from a timer switch is too good, it worked on 1V instead of 3V on my circuit. I knew about it but I thought CMOS would work with wide voltages but not for that clock. So I added another battery to supply the clock and added a transistor to pull up the alarm signal up to 3V.
I chose components to minimize chip and connection count. But the choice of components off the shelf is limited. More importantly, I misread an unimportant part of my own circuit, the gates are to be repeated on all signals in the bus, but I allocated components and space just for one signal. So I have no chips or no space for all the signals. But I can live with that for a prototype.
Without ground and supply rails, the soldering is a nightmare. Every connection is by a wire, and I didn't have the magnet wires, insulated wires with coating that melts when soldered. So I have to strip every wire before soldering using a blunt, large soldering iron. When I brought the iron, I wanted one that is powerful enough to for thick electrical repairs, and also doubles for electronic work if I ever needed. So the tip always touch two chip leads when soldering. It's a nightmare. But I soldered on hoping to get out of hell as soon as possible.
At the end it was spaghettis over and under a plate in 3-D. It was hell. Worse, nothing works that surprised me. The IO drivers all don't work so I don't know what's going on. And I have only a hand held multimeter to trouble shoot. Funny that the main fault was laughable. I used CMOS design for the first time as my real circuit needed to be low powered. The basic quad NAND gates have different pin outs with the TTL versions!!! Just 1 in the 4 gates have different pin outs, but just enough to make everything not working. I vaguely remember that it was to differentiate that it is CMOS rather than TTL. But nowadays you will use the same pinouts, even if it cost you more to manufacturer. But now the CMOS pinout is history and you have to remain compatible.
And since the circuit was a hopeless mess of spaghettis, I had to find another fresh circuit board to start over. Luckily I found an ancient copper stripped board in my garage just enough to fit the chips that I have. It now looks better but still a lot of spaghettis, but less painful to build.
The circuit at least work as expected but a lot of strange happenings, like on and off of motors and LED's when not expected. The power on reset doesn't work as the microprocessor in the real time clock takes a few seconds to reset, while my own circuit resets for a much shorter time. Now it's a random start, but since I cut down the number of states due to insufficient space and chips, it's only head and tails.
The manual reset doesn't work either. I suppose the pull-up resistor is too large to save current. But I can always reset by touching the contact with a wire connected to ground or supply.
The unexpected on and off is due to a long alarm signal. I have a timer circuit to control the
width of the pulse, and to isolated the alarm signal once activated. But I got it wrong assuming it's trivial. So I have to indulge into some Boolean math to arrive at an asynchronous finite state circuit with minimum gates, which have to be a modern classic. But I needed 3 NAND gates. So instead of blinking LED's to save current, some are not blinking to save some gates for the modern classic.It's working now for weeks on two AA batteries. But very recently I found out that the sparks of a small motor nearby will cause the circuit to change state for certain. It's no big deal as I have to redesign the whole thing anyway.
The perfect reverse osmosis system
Perfect also means a good price :-)
The feed shut off valve is not enough. It takes forever to shut off the system and restart. I suggest to add a plastic ball valve right after the feed valve. Surprisingly, the ball valve carried at Lowes carry a cancer causing material warning, but it's sold along side NSF approved tubings. I would buy a valve with John Guest connectors. And since JG seemed to be patented, there's always a minute but ultra fine JG symbol somewhere, even though the manufacturer's name wasn't on the component. This is very typical. Manufacturers don't normally make all the component of an RO system. So they mainly sell to OEM's, unmarked or marked with the OEM's name. BTW, JG is also a company producing many components.
You can easily find NSF approved 1/4" tubing in hardware stores, for fridge ice makers. For the filter housings, what can go wrong? It's hard to check if those components are NSF approved, as most makers sell them to OEM's. And then the whole system is approved rather than individual components. But I bet all housings are made of FDA approved food grade plastics, and that any housing looks like any others. But I'm not so sure about the O-rings used to seal the filters. There are NSF or FDA approved O-rings on sale fit for standard housings. And there are approved silicon grease to be applied on the O-rings to seal.
There are typically up to 3 pre filters about 10" long for residential use. The main purpose is to remove chlorine which attacks the membrane. But I made the mistake of choosing too good prefilters. The worse mistake is to use a 0.2 micron ceramic filter. When I looked at the data sheet, the pressure drop across the filter is 15 psi, though at a very high flow rate which doesn't occur at residential systems. So at 50 psi input feed, you could lose a lot of pressure just across one filter alone. The filters to buy are Matrikx branded. They have a stable and clear line of products. They have a good name and a lot of systems use them (I guess). They provide datasheets. You can get the top ones at as low as $10.
The static pressure is easy to measure. A pressure gauge costs a few dollars from hardware stores. Screw it on a garden tap, 3/4", and you get the static pressure, when all other taps are closed. For 1/4" RO systems, you just unscrew the 3/4" adapter typical on gauges, and you can screw the gauge directly into a JG ball valve for RO tanks. Now you just insert any tube into the valve and you get the static pressure with the valve open. But measuring the pressure when water is flowing is tricky. If the water don't flow, there's no pressure drop across the pre filters. I've seen attaching a gauge to a T adapter. Water is flowing straight through and the pressure is seemed to measure perpendicularly to the flow.
Filtered drinking water is measured in gpd, gallon per day, while the stated flow rate for pre-filters is typcally gpm, per minute. So the stated pressure drop at the high flow rate may not apply at very low flow rates. Anyway since I cannot know this, I minimize the pressure drop by choosing suitable filters.
I'll start with a 5 micron sediment filter, if you water supply isn't that dirty. Coarser filter is associated with larger dirt capacity and less pressure drop, a few psi. Then the 20,000 gal carbon chlorine filter is a no brainer. If you don't really know how much water you drink, it guarantees you only need to change filter once a year. If you know, you save money and time because the chlorine capacity is a lot larger than other filters, you only need to change filters once a long time. I estimated that the water passing through my filter will be 5,000 to 10,000 gal, so I only need to change filters once 2 to 4 years, considering the chlorine capacity alone. It also good for filtering VOC if by chance you got it, volatile organic compounds, which are basically vapor gas that the RO membrane can't deal with. The pressure drop is less than 3.5 psi and the size is about 0.6 micron.
It just happened that I have a 3 stage housing so I have to pick one more. Another same carbon filter is OK but there are a lot of other choices probably for non RO systems. The mistake I made was picking a 0.2 um one with a psi drop of 15, making it unsuitable for RO systems. The choice is between certified lead or bacteria rejection. Since my water feed is very decent, and since the membrane will deal with that at sub micron levels, I settled on a 0.5 um carbon filter with 8 psi drop, with half the chlorine capacity. There is some cyst reduction, bacteria that isn't killed by chlorine. Other reasons are price and availability.
The most important component used to be the membrane. But as I said, pumps cost a lot more. The only membrane to get is Filmtec, certified for 96 to 98% rejection. And 75 gpd is the only capacity you want. Any larger the rejection drops to 90%, and any other brands is just as good. Even if you don't drink that much water, the tank refills fast. And since you don't have 50 psi as assumed by most components, you have more design flexibility and more choice of good filters. After all, it's just $30.
15% to 20% of water pass through the membrane, while the rest go down the drain. What makes water pass through the membrane is a flow restrictor on the brine side (waste water) of the membrane. Interestingly, almost certainly you have a wrong flow restrictor. If you have a 75 gpd membrane, waste water is 4 times that, arriving at about 800 mL per minute, which is the standard restrictor to use. But, the Filmtec membrane recovery is 15% rather than 20%, which requires a larger capacity. Also, instead of 75 gpd at 50 psi, you have 40 psi across the membrane if you are lucky. And for pumpless systems, you have just about 20 psi when the tank is almost full.
You don't have much control over pressure unless you have a booster pump to vary the input psi, and a permeate pump to maintain a constant pressure across the membrane. In my area we need a pressure regulator so I can increase that to 100 psi risking bursting pipes anytime, or decrease at the expense of weaker showers. Other than that you can buy filters with larger or smaller psi drops. However since you can't measure that reliably, I suggest to get a few flow restrictors, test the system performance with a TDS meter, pick the best one and return the rest !!
It's worthwhile to make a bypass path across the restrictor, controlled by a ball valve. It's called flushing the membrane when you by pass the restrictor, when all water goes to drain to clean the membrane. With JG connectors, it only cost you a minute to make. NSF components are not required at the brine side. Expensive systems used to have that path, and of course a timer to flush everyday for a few minutes. Membranes need flushing regularly only if your system is at 98% I guess. It's easy to achieve over 95% and never flush. At $30 it's worthwhile to change the filter every year. But if you use it for a few years for the full design life, you feel better to flush every few months or a year. The waste water are black, mostly carbon resides from the filters.
After the invention of the "affordable" permeate filter, it's clear that prior pumpless systems are toys. No matter how good your filters and membranes are, you only operates at a fraction of the pressure. The pump comes with a new hydraulic valve, which cutoff the supply when the tank pressure is 90% of the feed, and turns on the supply when the pressure drops below 70%. Since the membrane always see full pressure, the high cut off allows the tank to fill more water at higher pressure, and the on pressure prevents starting the system every time for a minute when you just pour a glass of water. The higher pressure is important if previously your RO water can't get through to the fridge to make ice. Previously standard valves cut off at 66%, leaving you with 33% pressure across the membrane. Permeate pump not only save you water, because less water flows through, you get longer filter and membrane life.
The final filter is always after the tank. I wondered why. Until one day I tasted the tank water and it smells and taste like rubber. I think it's a taste of the bladder inside for cheap tanks at least. It's also a good idea to filter the water when you drink it, not when you store it in a tank. I always use NSF certified Omnipure. Unlike Matrikx carbon block filters, which are designed for chlorine capacity and minimize carbon residues clogging the membrane, the final filters are carbon granulates design for maximum bad taste reduction. And I can vouch for it. These filters are smaller and have a much lower capacity as the drinking water to total water ratio is at least 1 to 4 or 6. But still you may need to change every 6 month instead of a year.
Cheap tanks rust easily on the outside and taste like rubber. They also lost pressure fast. There's a tire like bladder inside. When you lost pressure, you need to pump water out using a tire pump, measure the air pressure at 7 psi for typical tanks. Of course you better get a new tank when you lost pressure. The one to get is Flowmatic RO Pro tank. It's NSF listed. It's plastic so it doesn't rust, at least on the outside. The shape and color is a lot more pleasant than metal tanks. It fits well under the sink like a tall slim guy rather than a short fat guy with a beer belly. 4 gallon total is about the largest size that fit comfortably under the sink with space for other things. Practically you get only 2+ gallon for pumpless systems, or 3+ with a permeate pump. You also get a nice reserve in earthquake zones, enough for at least 6 people's maximum drinking needs for one day, but a least a few days for survival.
You have little choice about the faucet. A designer faucet cost you more than all the other components. Most people use Touch Flo faucets, look decent, cheap, and NSF listed. There was a settlement about lead many years ago. So they won't make the mistake twice. An ordinary drill and a special bit from hardware stores will make an extra hole on your sink, but depending on the material, I still have nightmares about it. But in my neighborhood, you can't find people to come in and drill a hole for you, not at a price you want to pay. You rather hire any heavy machinery you need from the hardware stores and blast everything yourself.
You need an air gap somewhere to prevent back flow of waste water. If the law allows you can use a check valve instead. Air gap at the faucet is a bad idea unless the faucet comes with tubings attached. It's a nightmare to attach all the tubes under the sink for a compact faucet at the very corner. You can use the air gap for the dishwasher. There are air gaps designed for that with extra RO input.
A digital TDS meter is a must. It's cheap and compact anyway. It's a measure of the conductivity of the water, which reflects directly the dissolved solids in the water. And since only the membrane can remove dissolved solids, the meter tells you how well your system is doing, if put together correctly at all. Typically for hard water, the supply is 400 ppm. If the RO water is 20 ppm, you get 95% rejection. It can be addictive. If you are a Monk person, it's worthwhile to get one of those that mounted on the sink to give readings continuously.
The other parameters that indicates your system is working correctly is a flow rate meter. But it's rather not necessary. You just need a measuring cup and a stopwatch. You get a good idea of the flow rate out of the restrictor and out of the membrane (when the tank is shut off). Restrictors can be inaccurate because of deposits, which is at higher concentration at the brine side.
Now there are low cost total volume flow meters on the market made of FDA approved plastic. You can program 5 reminders to change your filters according to total volume passing through. Nobody have a good idea how much water they actually use. Filters are either changed prematurely along with all other filters, or way too late. So the saving in filter cost will make the meter virtually free. You also get peace of mind. But you need to know the design capacity of the filters. But actually you need two, since there are three flow volumes in the system, the supply, the permeate (drinking) and brine (waste). Since the permeate and brine are never exactly 1:4 or any other ratio as designed, you need two meters to get all the three flow volumes, unless you have a good idea what the measured ratio actually is.
You need to disinfect and clean the system on a regularly basis, say once a year. The membrane is tricky if you decide to keep it for a few years. It can only tolerate low concentrations of chemicals and you need to pump the solutions through the membrane constantly for limited time. The details are on their website. I would rather flow it away after a year, or just soak it. To disinfect you need H2O2 from pharmacy and dilute about 10 times (check website). I'll soak it in the filter housing instead of pumping it for the recommended period. I have no pump. Then I'll put fresh solution in the empty filter housings, put the membrane back in it's housing, and turn on the feed supply. The H2O2 gets pumped across the membrane, but further diluted.
But if you actually bother to disinfect the membrane, you might just as well buy NaOH and HCL solutions from science stores and perform the alkaline and acidic cleaning steps as recommended.
Before the membrane, you can just as well pump higher concentration of cleaning and disinfecting solutions around the system, the tank, the tubes and the filter housings. Then using the tank to pump the solutions all the way to the fridge. Of course you need to pump a lot of fresh water to get rid of the solutions, and throw away the ice.
I think that's about it. Now the cost.
JG Valve's and T's $30
Filter housing $60
Filter 1 $10
Filter 2 $10
Filter 3 $15
Filter 4 $15
Membrane $40
Pump $45
cut-off valve $15
Tank $70
Faucet $30
TDS meter $20
Flow meter $30
Total $390
This is the retail component prices. If you buy in bulk and sell whole systems, you make a decent profit without much work. The JG connectors are a snap to use.
The feed shut off valve is not enough. It takes forever to shut off the system and restart. I suggest to add a plastic ball valve right after the feed valve. Surprisingly, the ball valve carried at Lowes carry a cancer causing material warning, but it's sold along side NSF approved tubings. I would buy a valve with John Guest connectors. And since JG seemed to be patented, there's always a minute but ultra fine JG symbol somewhere, even though the manufacturer's name wasn't on the component. This is very typical. Manufacturers don't normally make all the component of an RO system. So they mainly sell to OEM's, unmarked or marked with the OEM's name. BTW, JG is also a company producing many components.
You can easily find NSF approved 1/4" tubing in hardware stores, for fridge ice makers. For the filter housings, what can go wrong? It's hard to check if those components are NSF approved, as most makers sell them to OEM's. And then the whole system is approved rather than individual components. But I bet all housings are made of FDA approved food grade plastics, and that any housing looks like any others. But I'm not so sure about the O-rings used to seal the filters. There are NSF or FDA approved O-rings on sale fit for standard housings. And there are approved silicon grease to be applied on the O-rings to seal.
There are typically up to 3 pre filters about 10" long for residential use. The main purpose is to remove chlorine which attacks the membrane. But I made the mistake of choosing too good prefilters. The worse mistake is to use a 0.2 micron ceramic filter. When I looked at the data sheet, the pressure drop across the filter is 15 psi, though at a very high flow rate which doesn't occur at residential systems. So at 50 psi input feed, you could lose a lot of pressure just across one filter alone. The filters to buy are Matrikx branded. They have a stable and clear line of products. They have a good name and a lot of systems use them (I guess). They provide datasheets. You can get the top ones at as low as $10.
The static pressure is easy to measure. A pressure gauge costs a few dollars from hardware stores. Screw it on a garden tap, 3/4", and you get the static pressure, when all other taps are closed. For 1/4" RO systems, you just unscrew the 3/4" adapter typical on gauges, and you can screw the gauge directly into a JG ball valve for RO tanks. Now you just insert any tube into the valve and you get the static pressure with the valve open. But measuring the pressure when water is flowing is tricky. If the water don't flow, there's no pressure drop across the pre filters. I've seen attaching a gauge to a T adapter. Water is flowing straight through and the pressure is seemed to measure perpendicularly to the flow.
Filtered drinking water is measured in gpd, gallon per day, while the stated flow rate for pre-filters is typcally gpm, per minute. So the stated pressure drop at the high flow rate may not apply at very low flow rates. Anyway since I cannot know this, I minimize the pressure drop by choosing suitable filters.
I'll start with a 5 micron sediment filter, if you water supply isn't that dirty. Coarser filter is associated with larger dirt capacity and less pressure drop, a few psi. Then the 20,000 gal carbon chlorine filter is a no brainer. If you don't really know how much water you drink, it guarantees you only need to change filter once a year. If you know, you save money and time because the chlorine capacity is a lot larger than other filters, you only need to change filters once a long time. I estimated that the water passing through my filter will be 5,000 to 10,000 gal, so I only need to change filters once 2 to 4 years, considering the chlorine capacity alone. It also good for filtering VOC if by chance you got it, volatile organic compounds, which are basically vapor gas that the RO membrane can't deal with. The pressure drop is less than 3.5 psi and the size is about 0.6 micron.
It just happened that I have a 3 stage housing so I have to pick one more. Another same carbon filter is OK but there are a lot of other choices probably for non RO systems. The mistake I made was picking a 0.2 um one with a psi drop of 15, making it unsuitable for RO systems. The choice is between certified lead or bacteria rejection. Since my water feed is very decent, and since the membrane will deal with that at sub micron levels, I settled on a 0.5 um carbon filter with 8 psi drop, with half the chlorine capacity. There is some cyst reduction, bacteria that isn't killed by chlorine. Other reasons are price and availability.
The most important component used to be the membrane. But as I said, pumps cost a lot more. The only membrane to get is Filmtec, certified for 96 to 98% rejection. And 75 gpd is the only capacity you want. Any larger the rejection drops to 90%, and any other brands is just as good. Even if you don't drink that much water, the tank refills fast. And since you don't have 50 psi as assumed by most components, you have more design flexibility and more choice of good filters. After all, it's just $30.
15% to 20% of water pass through the membrane, while the rest go down the drain. What makes water pass through the membrane is a flow restrictor on the brine side (waste water) of the membrane. Interestingly, almost certainly you have a wrong flow restrictor. If you have a 75 gpd membrane, waste water is 4 times that, arriving at about 800 mL per minute, which is the standard restrictor to use. But, the Filmtec membrane recovery is 15% rather than 20%, which requires a larger capacity. Also, instead of 75 gpd at 50 psi, you have 40 psi across the membrane if you are lucky. And for pumpless systems, you have just about 20 psi when the tank is almost full.
You don't have much control over pressure unless you have a booster pump to vary the input psi, and a permeate pump to maintain a constant pressure across the membrane. In my area we need a pressure regulator so I can increase that to 100 psi risking bursting pipes anytime, or decrease at the expense of weaker showers. Other than that you can buy filters with larger or smaller psi drops. However since you can't measure that reliably, I suggest to get a few flow restrictors, test the system performance with a TDS meter, pick the best one and return the rest !!
It's worthwhile to make a bypass path across the restrictor, controlled by a ball valve. It's called flushing the membrane when you by pass the restrictor, when all water goes to drain to clean the membrane. With JG connectors, it only cost you a minute to make. NSF components are not required at the brine side. Expensive systems used to have that path, and of course a timer to flush everyday for a few minutes. Membranes need flushing regularly only if your system is at 98% I guess. It's easy to achieve over 95% and never flush. At $30 it's worthwhile to change the filter every year. But if you use it for a few years for the full design life, you feel better to flush every few months or a year. The waste water are black, mostly carbon resides from the filters.
After the invention of the "affordable" permeate filter, it's clear that prior pumpless systems are toys. No matter how good your filters and membranes are, you only operates at a fraction of the pressure. The pump comes with a new hydraulic valve, which cutoff the supply when the tank pressure is 90% of the feed, and turns on the supply when the pressure drops below 70%. Since the membrane always see full pressure, the high cut off allows the tank to fill more water at higher pressure, and the on pressure prevents starting the system every time for a minute when you just pour a glass of water. The higher pressure is important if previously your RO water can't get through to the fridge to make ice. Previously standard valves cut off at 66%, leaving you with 33% pressure across the membrane. Permeate pump not only save you water, because less water flows through, you get longer filter and membrane life.
The final filter is always after the tank. I wondered why. Until one day I tasted the tank water and it smells and taste like rubber. I think it's a taste of the bladder inside for cheap tanks at least. It's also a good idea to filter the water when you drink it, not when you store it in a tank. I always use NSF certified Omnipure. Unlike Matrikx carbon block filters, which are designed for chlorine capacity and minimize carbon residues clogging the membrane, the final filters are carbon granulates design for maximum bad taste reduction. And I can vouch for it. These filters are smaller and have a much lower capacity as the drinking water to total water ratio is at least 1 to 4 or 6. But still you may need to change every 6 month instead of a year.
Cheap tanks rust easily on the outside and taste like rubber. They also lost pressure fast. There's a tire like bladder inside. When you lost pressure, you need to pump water out using a tire pump, measure the air pressure at 7 psi for typical tanks. Of course you better get a new tank when you lost pressure. The one to get is Flowmatic RO Pro tank. It's NSF listed. It's plastic so it doesn't rust, at least on the outside. The shape and color is a lot more pleasant than metal tanks. It fits well under the sink like a tall slim guy rather than a short fat guy with a beer belly. 4 gallon total is about the largest size that fit comfortably under the sink with space for other things. Practically you get only 2+ gallon for pumpless systems, or 3+ with a permeate pump. You also get a nice reserve in earthquake zones, enough for at least 6 people's maximum drinking needs for one day, but a least a few days for survival.
You have little choice about the faucet. A designer faucet cost you more than all the other components. Most people use Touch Flo faucets, look decent, cheap, and NSF listed. There was a settlement about lead many years ago. So they won't make the mistake twice. An ordinary drill and a special bit from hardware stores will make an extra hole on your sink, but depending on the material, I still have nightmares about it. But in my neighborhood, you can't find people to come in and drill a hole for you, not at a price you want to pay. You rather hire any heavy machinery you need from the hardware stores and blast everything yourself.
You need an air gap somewhere to prevent back flow of waste water. If the law allows you can use a check valve instead. Air gap at the faucet is a bad idea unless the faucet comes with tubings attached. It's a nightmare to attach all the tubes under the sink for a compact faucet at the very corner. You can use the air gap for the dishwasher. There are air gaps designed for that with extra RO input.
A digital TDS meter is a must. It's cheap and compact anyway. It's a measure of the conductivity of the water, which reflects directly the dissolved solids in the water. And since only the membrane can remove dissolved solids, the meter tells you how well your system is doing, if put together correctly at all. Typically for hard water, the supply is 400 ppm. If the RO water is 20 ppm, you get 95% rejection. It can be addictive. If you are a Monk person, it's worthwhile to get one of those that mounted on the sink to give readings continuously.
The other parameters that indicates your system is working correctly is a flow rate meter. But it's rather not necessary. You just need a measuring cup and a stopwatch. You get a good idea of the flow rate out of the restrictor and out of the membrane (when the tank is shut off). Restrictors can be inaccurate because of deposits, which is at higher concentration at the brine side.
Now there are low cost total volume flow meters on the market made of FDA approved plastic. You can program 5 reminders to change your filters according to total volume passing through. Nobody have a good idea how much water they actually use. Filters are either changed prematurely along with all other filters, or way too late. So the saving in filter cost will make the meter virtually free. You also get peace of mind. But you need to know the design capacity of the filters. But actually you need two, since there are three flow volumes in the system, the supply, the permeate (drinking) and brine (waste). Since the permeate and brine are never exactly 1:4 or any other ratio as designed, you need two meters to get all the three flow volumes, unless you have a good idea what the measured ratio actually is.
You need to disinfect and clean the system on a regularly basis, say once a year. The membrane is tricky if you decide to keep it for a few years. It can only tolerate low concentrations of chemicals and you need to pump the solutions through the membrane constantly for limited time. The details are on their website. I would rather flow it away after a year, or just soak it. To disinfect you need H2O2 from pharmacy and dilute about 10 times (check website). I'll soak it in the filter housing instead of pumping it for the recommended period. I have no pump. Then I'll put fresh solution in the empty filter housings, put the membrane back in it's housing, and turn on the feed supply. The H2O2 gets pumped across the membrane, but further diluted.
But if you actually bother to disinfect the membrane, you might just as well buy NaOH and HCL solutions from science stores and perform the alkaline and acidic cleaning steps as recommended.
Before the membrane, you can just as well pump higher concentration of cleaning and disinfecting solutions around the system, the tank, the tubes and the filter housings. Then using the tank to pump the solutions all the way to the fridge. Of course you need to pump a lot of fresh water to get rid of the solutions, and throw away the ice.
I think that's about it. Now the cost.
JG Valve's and T's $30
Filter housing $60
Filter 1 $10
Filter 2 $10
Filter 3 $15
Filter 4 $15
Membrane $40
Pump $45
cut-off valve $15
Tank $70
Faucet $30
TDS meter $20
Flow meter $30
Total $390
This is the retail component prices. If you buy in bulk and sell whole systems, you make a decent profit without much work. The JG connectors are a snap to use.
Tuesday, September 11, 2007
The perfect water
First of all, most reverse osmosis system are designed to have a recovery of 20%, that is, for every 1 cup you drink, you throw away 4 cup. That sounds a lot, but you actually don't drink that much water. Baths and lawns are a lot more wasteful. More so is flushing the toilet. Somewhere in the world use sea water or reclaimed water to flush. Also, bottle water, such as the famous Fuji water now widely available in Trader Joe, seems a lot more wasteful, pumping up deep ancient water and bring it over from so far away, in plastic bottles. Also many beverages you drink use RO water anyway. In good restaurants, if you don't want bottled water, they will give you tap water, filtered to taste good. It's worthwhile to include RO to avoid liabilities as bacteria and virus can hardly pass through. It's easy to achieve zero waste. You can feed the water to your irrigation system, or pump it back to the hot water supply.RO systems used to be very expensive, $1000?, and still are, $500?. Some years back some cheap RO systems appear on the market aimed at the masses at $100. The performance in terms of rejection rate of total dissolved solids (TDS) is 85%, compared to top of the line systems at 98%. 85 is a lot less than 98, but filtering out 85% of what need not be there sounds enough for a try. The DS are basically the hardness of the water, naturally occurring materials. But here we use Colorado river which is really hard. And if something goes wrong for a short while in the public system, softening the impact by 85% isn't that bad. And if you can filter out 85% of the bacteria, that's good enough without costing an arm and a leg. It's not that I couldn't afford expensive systems. But like computers, I don't know what components they put in. You cannot test it, for example, how much lead it rejects. You have to trust them. But I rather not.
But the cheap pumpless systems are a joke. The stated performance is for full water pressure, typically 50 psi (sorry rest of the world). But once the system starts working, the pressure across the RO membrane falls. These systems typically stops when the tank pressure reaches 30 psi, by this time the pressure across the membrane is only 20 psi, a fraction of the stated performance.
Typically small manufacturers don't know what exactly happens as the operating points drift away from the optimum point where all the components are guaranteed. But as long as the final TDS reading looks good, they are selling it. Typically, the rejection rate maintains at low pressure, at the expense of wasting much more water! Not just 20%, but 10% and less.
To control the pressure, you need a pump. But pump's able to deal with 50 psi are not toys. Just a booster pump cost more than a cheap RO system. The alternative is to use an open tank and let the RO water flows into the tank slowly. So you are fortunate if you are a fish. For aquarium applications, the water is as good as any top of the line systems. But without a pressurized tank, you either go fetch water from under sink, or use a delivery pump. So a pump again, though at lower pressure the pump is cheaper, but not by a lot needing NSF testing. And you start to worry about the air quality, and air borne bacteria. Until the permeate pump, which is a lot cheaper without electricity and at lower pressure. Basically it's a weak hydraulic pump, pumping filtered water into the pressurized tank. With a pump, the pressure of the tank is isolated from the membrane. So the membrane is seeing the full water pressure all the time.
I'm going to describe safe materials and the correct design of an RO system. Indeed if there are not so many one man company selling put together systems, I may start selling too.
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