Acid Pump - Level Indicator Working!

Twice now I've had the level indicator work.  It worked exactly as I wanted it to.  It tripped at around a gallon so I have a couple of days to actually do something about it, and the House Controller indicated low so that I didn't even have to walk by the injector to tell what was going on.  I only added a gallon when it tripped so I could see that it worked when the gallon was gone.  So, anyone wanting to try something like this, here's a working example.

Now, I have something else to brag about.  On to the next project.

Long Term Data Collection

I had an interesting failure yesterday.  Something somewhere stopped working and my data stopped being recorded.  I have no idea if my devices stopped sending or Pachube stopped receiving but something stopped working.  This chart illustrates it:

The ... part is where data was not being saved.  So, there was a period of several hours where data just disappeared into a black hole.  My little devices don't have enough storage to hold something like that so I don't have a clue what went wrong.  Oh well, it's not like I can't interpolate the actual usage from experience, but it really is annoying.

Acid Pump Level Indicator Try #2

The glue dried on my latest attempt at measuring the level of acid in my acid injector.  This time it seems to be working.  I used the same float, but hooked it to a rod and led the rod out of the bucket so I could put a switch outside the acidic environment.  Since this one looks like it will work for a while, I'm putting it on my Swimming Pool page, or click here to go directly there.

Acid Pump, What Not to Do

So, I have the acid pump and it runs every other day; now I want to know when it is getting low so I can pour some more acid in it.  I looked at  various methods and asked around for suggestions.  Most of the answers I got, although really good suggestions, wouldn't work.  Ultrasonic had to have a clear path to the liquid level, and the acid fumes would rot the sensors. Capacitance sensors were way too expensive except for the one you can build from foil and sensitive circuits, but they won't last when exposed to the weather.  Weight sensors under the bucket were either too expensive or wouldn't survive the outdoors.  Conductors through the side of the bucket would dissolve eventually in the acid.  Various float devices have metal parts that will rot in the acid. An external tube with a magnetic float inside will probably leak since the input is below the level of the acid.  However, this gave me an idea.

Suppose I suspended a float from a string through the lid of the bucket and hooked the string to a lever on a microswitch?  That actually sounded like it might work.  There would be no weight on the string until the float was down far enough and then it would pull the switch down.  So, I needed to find some string that wouldn't dissolve in the acid as well as a float.  The float was easy; toilet floats are made as cheaply as possible and that suits me just fine because a cheap plastic float that has no metal components will survive the acid.  Home Depot had one for a few dollars so I picked one up.  I looked for PVC string, twine or cord and came up empty, but there is such a thing as Teflon string for sealing plumbing parts.  I ordered this stuff:

Nice product for packing plumbing threads.  Should be just the ticket.  So, I rigged up a microswitch in one of the duplex boxes that will protect it, attached the string to the float and tied it off to the switch.  After modifying the code in the timer to sense the switch, I was ready to try it out.

The switch is in the gray box and you can barely see the Teflon string going into the bucket through a little hole in the top.  Here is an inside view of the float:

Simple.  The float will only pull on the microswitch when the level is low enough and that should survive the environment.  But....

The string dissolved in the acid.  WTF?  This is Teflon, Teflon doesn't dissolve in acids.  So I tested a bit more of the string and sure enough, it flat out dissolved in the acid.  Drug out my microscope and took a look at it.  It appears to be string coated with a thick layer of Teflon dust or grease or something.  Should work fine for sealing and lubricating plumbing joints (what it was actually designed to do), but the string just goes away in a concentrated acid bath.  So, I got some Teflon tape (had a roll of that already) and used it instead.  I hooked it to the float and then spun the float to twist the tape into a thread.  Worked nicely and then hooked the thread to the switch.  Now I was getting somewhere.  

However, the float would move around and bind up on the tubing to the intake for the pump.  The thread bound up on the hole through the lid and the hole in the bottom of the duplex box.  The Teflon would come untied from the microswitch too easily and it was horrible trying to adjust, Teflon is slick and the knots would untie themselves!

Some great ideas just don't work when you actually try them out.

Acid Injection Pump

In the years I've had this pool I have gotten increasingly frustrated with having to check it often to be sure the pH is correct.  Chlorine generators on salt water pools tend to raise the pH a little each time they run.  The chemistry of this is described out there, but us pool owners have to deal with it.  The sad part is that the pool companies don't tell us in advance.  I would still have a salt pool, but it would have been nice to know what to expect going in.

Anyway, I finally decided to build an acid injection system and stop having to worry about the pH all the time.  It is described on the Swimming Pool tab above, or click here to go direct to the description.  This is yet another ongoing project that will evolve over time as I get or steal new ideas.

Swimming Pool Fittings (part 5)

 Those that are following this are probably getting tired of me spouting off about 2 inch fittings for a swimming pool.  Well, this should be the last post for a while about this.  I have finally found the solution I was looking for. A way to connect rigid pipe to flexible pipe to support a solar heater without having to go to ten different stores or wait weeks for parts to arrive.  I made my own barb fitting.

First get a union and cut a ring about 3/8 of an inch wide off the end of it.  This can be made easier by putting the union on the end of a pipe (no, don't glue it on) and clamp down the pipe.  I used a reciprocating saw for this, but a hack saw will work fine.

Now glue it to the end of the fitting you want to convert to a barb.  I used a street ell in this example since that is the fitting I need.  You can use a piece of pipe just as easily.  However, there is a possible problem.  The recommended way to glue these is to use a primer and then the glue.  That can fall apart when you put it under pressure.  Especially if you have cyclically changing pressure like a pump turning on and off at various times.  Exactly what I want to use it for.  Well, a call to the glue company solved this problem for me.  Use the "Red Hot" version of the glue WITHOUT any primer.  It seems the primer and glue combination is actually weaker than the regular old glue used alone and to get a really good bond, use the "Red Hot" version.  Some areas require that you use the primer; if that's one of your problems, just paint it with primer after you're done.  They can't tell the difference. 

Wait an hour for the glue to set up some, go to the bench grinder and bevel the ring.  If you don't have a bench grinder, use a rasp and finish it off with sand paper.  If you don't have a rasp, go to the store and get one.

This is the end result.  The barb can be tailored to fit the flexible tube exactly the way you want it to and it will hold.  My solar heater is back online running just fine at less than 8 pounds of pressure.  Here is a picture of the 'real' fitting that is needed.  If you can find this thing, it will make your life easier, but none, that is exactly zero, of the places in town that I managed to contact had even heard of anything like this.  If it wasn't for the price of gasoline I'd take this thing to each of the stores and show them that it exists and they should carry a couple of them.  But, I noticed during this project that Home Depot doesn't even carry a 2 inch street ell in their store stock; I had to go to either Ace Hardware or Lowe's to get one.  It's also nice to know that I can take this fitting and reuse it even though I cut it off the end of a pipe and it has a piece of 2 inch inside of it.  All I have to do is use either an inside coupler or a pipe extender to hook it up.  These two pieces of plumbing apparatus are basically unknown and not carried by stores.  So, this project has bumped up my experience level and now, I pass it on to you.

Now, I promise I won't talk about fittings again until I get the flexible tubing in that I ordered.

Next project??

Swimming Pool Fittings (part 4)

OK, I think I have the plumbing problem for solar heating on my swimming pool under control.  The latest set of plumbing parts came in and I've been testing fit and construction.  Everything seems to work.  I can create a connection that is short and will hold a flexible hose clamped around it just fine.  I used the pipe extender I mentioned below.  I'm still at least a week away from having the proper flexible tubing, but I only need that for one joint because I already have enough for the rest.

Shown above is the fitting before I cut some of it off and then how it can be inserted into fittings and pipe to make a secure connection to a flexible tube.  This way I can construct a fitting anyplace I want to, like the end of a pipe or a street ell.  I hope other folks that have to deal with this stumble across this set of posts because this kind of thing can be a real pain.

This will all be installed day after tomorrow early in the morning.  It's 135 degrees F on my roof right now and there's no way I'm going up there.  So, now I move on to the automatic acid injector project for the pool.  The injector is actually running right now, but I haven't started writing it up.