Comments on: Compressed air fail: What a non-standard component!

By: William K.

William K. — Sat, 28 Sep 2013 00:23:57 +0000

So what is the motivation for putting two valves in series like that? If you want a safety shutoff that is reliable, use a “ross” valve, which is made for that exact purpose, and no other. Not good looking but very effective, and OSHA approved. And when they are open there is very little pressure drop. Of course, in this case I would have done a flow-pressure drop test, since the symptom was low air pressure during flow. That would have discovered the problem.

By: Will Holding

Will Holding — Fri, 27 Sep 2013 16:30:56 +0000

Bernie, that loop type setup you are referring to is called a “pressure balancing loop” and works very well- in plumbing, it is also used to balance the pressure drop between multiple body sprays in a shower.

There are a couple of “better” solutions to valve handle interference problem, and it sounds like this guy did not use any of them.
You can orient the valves so the handles are on the outside of the pipes, facing away from each other. Or you cann offset the valves one downstream of the other. Or you can cut the handle down, or better still mill a slot in a bit of bar stock to make a “T” handle, which swings in half the length of the level hande, still indicates valve position, and can be turned with as much torque as the lever handle, Or lastly and perhaps most simply, take the retainer nut off the handle and hang the handle near the valve on a wire from the pipe. This is an air line, so it’s an isolator valve, not an emergency shutoff.

By: Geoff Daly

Geoff Daly — Thu, 26 Sep 2013 14:57:49 +0000

This is not unknown for two valves to be too close when using a short nipple to join, instead of an intermediate Dart-union. Then, the valves could be orientated off-set or just cut the handles shorter so they did not interfere and not reposition a handle or use a longer nipple.