Auto compressor drain - how does this work?

[MilDoc]

http://www.harborfreightusa.com/usa/...o?itemid=46960

[onedash]

no idea but the compressor we had at work had a whole contraption attached to remove water automatically. The tank was the size of a car and the motor was huge....It had pipe ran throughout the warehouse and some of the drain pipes would still get a lot of condensation in them. They had regular outdoor water faucet knobs below each connection.

[Tom Slick]

Some auto drains I have worked on are held closed by air pressure, when the pressure drops low the valve opens and vents the water

[oakchas]

google got me this link: http://www.paragoncode.com/shop/compressor/

Google is your friend.

Actually, I'm glad you asked... I've been thinking about getting one of these too... and now, we both know how they work!

[cwsmith]

Automatic condensate drain valves come in a variety of types for industrial-type compressors. Some types are float-operated, trap, and solenoid-operated. With solenoids they can be time triggered, triggered on start-up or shut-down, or by electronic sensors that are placed in the drain leg.

The shape of the HF unit looks almost like a solenoid, but with solenoids the top is usually electrical with a conduit connector... this isn't obvious on the HF, so who knows. This could be an air-operated valve, which either activates on pressure build-up or loss. In most cases, the solenoid-operated drain valves are the most economical and reliable for light compressor applications. Air-operated valves pose some challenge in that you have to pipe the valve back to regulator area, usually on the stage relief valve or just before pressure regulator. With an electrically-activated solenoid, it can be wired into the switch box. With electric solenoids, you select either a normally-open or normally-closed valve.

CWS

Edit: I might add that air-operated valves may prove a reliability problem as dirt or debris from within the tank can foul the feed line to the drain actuating valve.

[cabinetman]

I thought about one of those valves many years ago. The main reason I never went with one was advice from an autobody guy who ran air tools all day long. According to him, the valve no matter how it's actuated will (should) perform as per its actuator. If electric, at startup, or air, by relief valve (genie) or some other fluctuation of air pressure. Well the trick he said was that it will (should) evacuate small amounts each time, but sludge buildup may continue due to remaining oil and moisture in the tank. Eventually you have a glob that blocks the valve. Having one hang open could tie you up a while until the problem is fixed. That would happen to me just when I have applied glue and need to fire some brads. His recommendation is what I've followed on different compressors is to drain daily. I usually get quite a bit of water each time and with the buildup of air, that "blast" to evacuate helps blow out grime with the water. I also have simplified the draining by having a flex plastic (neoprene) tube to lead to a low tray for capture. I just slide it out and dump.



"I'M NEVER WRONG - BUT I'M NOT ALWAYS RIGHT"

[lrogers]

I went the easy too. I removed the OEM drain cock and replaced with a street ell (male pipe thread one end, female on the other), added a 6" nipple so it would clear the tank and screwed a ball valve on the end. A simple 90 degree turn of the handle and the tank vents/drains.

[oakchas]

The HF valve set up "pops off" every time the compressor cycles. In frequent use, that's more than once a day.

The street ell and pipe give more area for sludge accumulation (theoretically) but I think that's of little concern. And once daily is sufficient, if frequently done. But those longer stretches when the compressor is unused... is when the repeated heating and cooling will create the most condensation. So you need the big blast of air/water/sludge out before the day's work starts.

In dusty areas you may want to add better filtration to the air inlet of the compressor. this should keep most stuff from getting in in the first place. so we're talking mini micron sized dust particulate here... and if it's popping off frequently, that should keep it clear(er).

I think, if I were installing one of these, or I should say, when I do... I will add a full flow shut off and a plugged or a valved TEE before the pop off & leave it open to the autodrain. That way, if it sits unused for a few days, I can spin out the plug or open the "bypass valve" to get the big blast before starting. And, if the auto drain plugs, I can isolate it without having to evacuate all the air in the tank.

[Thom2]

The unit I have operates off of differential pressure, inside there's a diaphragm with a pinhole in it, any time the differential pressure is enough, it overpowers a spring and opens a needle valve to blow off air. The really nice thing about these units is that they don't require the extra line from the unloader valve.

I also ran an elbow to a 't' and put the automatic drain on one side of the 't' and a ball valve on the other, for those times that I wanted to drain the tank in a hurry.

I posted pics of my setup in this thread .....
http://www.bt3central.com/showthread.php?t=24899