Valves for vacuum

[wwaldner]

Looking at various setups for vacuum tables, I see there are a couple of different valves being put into use.
1. Ball valve
2. Knife/guillotine (rv drain valves)
3. Some form or other of automated values

Between the knife and ball values, what seems to be the better choice. I expect the ball valves to be difficult to operate, especially with a bit of grit accumulation. Do the knife valves hold up and seal well? I was hoping to setup a system like Gary's K.I.S.S where valves are opened and closed from the end of the table. This basic idea is the handles for the knife valve is extended to edge of table using long rods.
thanks

[Brady Watson]

Knife valves are the way to go...but get the stainless ones. The plastic ones are only good for like 7 Hg". The ball valves are hard on the hands and awkward when doing production. Definitely think about pneumatic actuation...it is NOT cheap, but a pleasure to use AND you can put the valves/manifold anywhere. I've got mine mid table because of the indexer at X0 and an 18' long table I don't want to walk every time I need to open/close one...

-B

[Gary Campbell]

Brady is dead on. https://youtu.be/iXJhTz-Jc7c

[wwaldner]

That looks like fun. Do you have a source for the parts? Only place that I have been able to locate the valves with SS paddles.

[Gary Campbell]

The valves are Valterra 4201 (white) for PVC and 5201 (black) Google em up.

The air cylinders come from McMaster Carr or Automation Direct

[Brady Watson]

Since you have to make your own actuators, what Gary posted is as good as the BOM gets. I think I used some maple to sandwich the cylinders and lock them onto the valve bodies. Nutin fancy...

IIRC it was about $1000 to do the 2" SS valves and all the cylinders, tubing and fittings (incl. switches). I got everything from McMaster - and another 'Thanks Gary' is due for sharing info.

-B

[wwaldner]

Thanks guys. Since this is my first foray into this, I think I will go with manual gates with option to automate later. Thanks for the help sorting this out

[JimmyD]

Gate valves are absolutely the way to go. No question that automation is convenient, but it's also expensive. It can be done much less expesively by manually operating the valves. Here is what I did on my table. Works great, zero issues. Search for "Valterra Waste Valve with Flexible Cable". Cable is 72" long.

Any questions, just ask.
Jim

[wwaldner]

Thanks Jim, that looks pretty ingenious. My search yielded only 3" valve bodies, which it looks like you used and then reduced to 2".

[JimmyD]

Correct. 3" plenum to 3" valves reduced to 2" and then flexible PVC to the bottom of the table. Screw on flanges at the bottom of the table for connecting the 2" PVC hose.