DIY 3-Way Valve

mck > reef > equipment > diy valve            

 

This page is dedicated to an attempt to make a home-made valve similar to those provided by Oceans Motion. I really wanted to slow down the cycle beyond their 1 rpm. I know there are ways to slow that valve down, but this seemed like a great challenge for me - and I was hoping something I could accomplish for less than an OM valve or a Hayward valve.

 

To cut to the chase, the valve I built and installed did not have enough torque to spin the internal valve assembly. It worked in dry runs, but when installed it bound up. I think this could be corrected by utilizing a larger-diameter pump impeller and (especially) magnet. Someday in the future I will try this again, and I'm sure it can work. In the meantime, I'm using a nice reliable OM valve. I will also, someday, update this page with an idea for a valve - version 2.0 - that is considerably smaller than this one. For now, keep reading and check out the photos.

 

 

So, here goes!

 

I had a few ideas and kept hitting roadblocks on how to rotate the valve internals and keep it all water-tight. Then someone pointed me at this system, by Weatherson. His use of the Iwaki pump impeller was ingenious and I stole the idea immediately!

 

My goals for this were to make a valve with:

  • basically an infinitely adjustable rotational speed,
  • common, easily obtainable parts,
  • common household tools,
  • a lower cost than commercially available valves.

 

So, here's my DIY Valve, Version 1.0 (click on any image to open a larger one):

 

The body of the valve is a 2" sanitary 4-way, with a 1"-2" spigot fitting in the bottom for the inlet. I bought scrap 2" UHMW rod on Ebay for the internals of the valve. I bought a used Iwaki 10RT on ebay as well to scavenge the impeller assembly.

 

I gutted the Iwaki, keeping the magnet, impeller, rear casing, and the metal axle that the magnet rotates on. I added the cog in this picture later.

Scavenged Iwaki Pump Parts

 

I cut the UHMW to the same length as the height of the sanitary fitting, slid the UHMW rod into the valve body and used a Sharpie to outline the side ports on the rod. I marked it so that when one port is full open, the other is full closed, but as soon as the rod rotated to the point that the open side began to close the other side began to open. It sounds more complex than it is, really.

 

I used my hand drill to bore out the UHMW to the point where the side opening would be:

Drilling Out The UHMW

 

Drilling Out The UHMW

 

And then used a dremel to cut out the side port and clean it up. This was messy (plastic shavings everywhere) but easy.

Drilling Out The UHMW

 

Drilling Out The UHMW

 

Drilling Out The UHMW

 

Then I used the dremel to notch the top of the UHMW to accept the Iwaki impeller. This was surprisingly easy.

Notching The UHMW For The Impeller

 

Notching The UHMW For The Impeller

 

Notching The UHMW For The Impeller

 

I cut the spigot fitting down a bit shorter, test fit everything, and then cut the bottom of the UHMW off so that it was flush with the top of the valve. Here's a pic with the Iwaki impeller sitting on top.

Test Assembly

 

I tried rotating the valve and had a few problems. The friction was too high for the impeller, which can't transmit much torque because it uses a magnet - no direct connection. I sanded down the inside of the sanitary fitting, and the outside of the UHMW until that spun freely by hand... still too much friction for the impeller assembly though. I narrowed it down the the spigot fitting.

 

I cut a short piece off the bottom of the UHMW, used the dremel to notch it and make the inside a little wider so it would fit into the spigot like this:

UHMW Internal Bearing

 

UHMW Internal Bearing

 

This piece acted like a bearing. Now the UHMW was rotating against another UHMW piece. This was enough to get the friction down to the point that the impeller would rotate the valve!

 

To rotate the valve I bought a used 110-V 1/10rpm motor off ebay. I also bought plastic cogs and a plastic chain. I cut the spokes off one of the cogs so that it pressure fit onto the impeller magnet. The cogs were different sizes, and will result in the impeller spinning at 1/20 rpm. Perfect for my flow goals.

Motor & Impeller Assembly & Associated Gears

 

I bought a scrap sheet of 1/2" PVC off ebay, and used it to create flanges for the top of the valve. [ok ok, I called in a favor and had a guy with access to a machine shop make the flanges for me, but it is completely feasible to do this at home with hole saws and drill bits!] I cut a hole in the lower flange the same size as the sanitary fitting, and glued it in place - PVC to PVC, this was easy. I cut a hole in the top half of the flange for the impeller housing, which I glued in using WeldOn. This wound up not adhering. I thought the impeller housing was Noryll and bought a Weld-On adhesive for that. In hindsight, I think the housing is polypropylene. There's not much that will adhere to it. I wound up using a LOT of PVC/ABS adhesive to seal this and it held, although I wouldn't trust this in a location it could get bumped. See pics below.

 

With the 1/8" rubber gasket from Ace Hardware between the two flanges, the impeller puts no weight on the UHMW - further reducing the system friction. I used more of the PVC sheet to make a base for the motor. Here's the whole assembly. You can see how wide the valve became, reducing from the 2" sanitary fitting to 1" pipe. A lot more reducers than you would think.

 

Test-running this dry, it worked great. The valve spun 360-degrees freely, with minimal friction and binding. Interestingly, it would only rotate in one direction; if I switched the motor leads to run it the other way the valve would bind and not rotate.

 

After installation, I was VERY disappointed to see that the valve would not rotate. The motor spun the magnet, but the magnet did not have the torque required to spin the impeller and valve.