monroews
commented
6 years ago My proposal for the drain location was through the bottom, but in the back of the CHT so that it doesn't require making the tanks even longer. But not a big deal if it is more convenient for some reason to have the drains in the front of the CHT.
The CHT should be mounted to the wall with a system that allows it to move up and down for final adjustment. There are a couple of issues here. We previously concluded that all chlorine float valves should be installed so that the orifice is submerged to reduce the rate of clogging. That is because it is the CO2 in the atmosphere that causes CaCO3 to precipitate. The extra pieces required between the valve mechanism and the float to cause the valve orifice to be submerged will change the elevation of the free surface. Given that all CHTs are in the same module, that means that all float valves must be installed identically. So either we modify all float valves so that the orifice is submerged OR we keep the system simpler and more elegant and require a bit more maintenance with vinegar to keep the chlorine valves clean. I suggest you check with Antonio on this decision. I don't have any data on the difference that submergence of the orifice makes.
If we can get the fluid levels set within a few mm of each other, then it shouldn't be necessary to provide additional adjustment. You may decide to not submerge the orifices and in that case I'd suggest switching to the float valves that are NOT adjustable. If I recall correctly, the float valves have discrete adjustments and I don't think that adjustment is fine enough to actually be used to set the height of the fluid level.
A piece of plywood screwed to the concrete wall that has stainless steel carriage bolts (with washers) coming through slots in the back of the CHT panel would be my recommended way to make it possible to adjust the height.
Adjustment should only be required when starting up the plant.
My comment about smaller pipes is because you mentioned a hole saw size that seemed much larger than 1/2". My suggestion is that you use 1/2" for the drains.
Monroe:
constant head tanks for dose controllers with integrated calibration columns. Dose controllers will be needed at the two plants currently under construction. Has the new design been fabricated in the APP workshop? Ideally this new design would be tested BEFORE installation. I'd suggest testing it at Tamara.
Ethan:
This is on the radar, but will be hard to pull off before installation in Zamorano. It is on the todo list. The original design with pipe weirs that split a partition wall was exceedingly difficult to get water tight. Therefore I changed this to regular pipe stubs that fit in the drain and can be removed to drain the tanks - thus eliminating the need for drain valves in the drain line. I included a picture of this improvement in the new design attached. I also edited the lid design to reduce material use and improve fabrication ease, and I edited the valve placement to facilitate shutoff-valve access.
Monroe:
The pipe stubs that fit in the drain will leak and so I don't think that is a workable design. We can get away with those types of drains in the plant because a small leak is okay in the plant. But I don't think it will be okay with the chemicals.
You could certainly have overflow pipes in each tank. That should be easier to fabricate. Perhaps you can put the overflow pipes in the back of the tank, off center so they don't interfere with the float. I like the valve placement.
Ethan:
Constant head tanks. I will add a dedicated overflow and dedicated drain next to one another in the front. I was thinking you might mention leakage... it's a fair point, although with small connections of 1/2", I have never seen connections without glue - my n might be too low, though! and furthermore the cost-risk-benefit dramatically favors adding a dedicated overflow. I don't want to have anything hanging off the back because I would like the tanks to sit squarely on a shelf if it is needed. However we end up connecting these CHTs, it's important it is secure! As for the adjustability, I think it would be preferable to set the tank level perfectly the first time and handle small adjustments with the float screw... What do you think? Does it help or hurt to have the CHT's so adjustable? Why does it ever get out of adjustment? (they shouldn't be adjusting this with the difference in water height from a full to empty stock tank...) Is it possible making it more adjustable has actually led to more mal-adjustment? Is there already a design for this I am not aware of? As for using smaller pipes... according to everyone here, it's very hard to find anything smaller than 1/2".