Pressurising PLC cabinet

[karivelm]

Does anybody the right recipe for pressurising a PLC cabinet so with instrument air so that the contaminents in the area do not enter the cabinet...

I heard something about making sure that the pressure is not to strong so that the cabinet does not become a bomb...

 

[harryting]

Pressure regulator + PRV.

 

[jkerekes]

They sell a device which includes the monitoring of the purging. What type of purging are you planning, X, Y, or Z?

Is this just out keep out dirt or is it for a hazardous area?

 

[karivelm]

it is just to keep out alumina...

 

[jkerekes]

I've used systems like this in the past. But mostly for equipment in hazardous areas:

http://www.iscenclosurecooling.com/...ion-systems/type-x-y-z-ex-p-and-ex-np-systems

 

[theDave2]

Purge / pressure systems for Hazardous areas use about 0.25" w.c. of pressure.

Yes, read that again. It's 1/4 Inch (water column) of pressure. That's 0.009 psi. Your standard pressure regulator doesn't go that low.

Do Not put shop air, even at a couple of psi, to the enclosure. It will blow stuff off the door, blow you across the room when you open the door and it smacks you in the head.

You will need to put a vent on the enclosure to that excessive pressure does not build up. Typically the vent is setup for 0.5" w.c.

 

[jkerekes]

Well those purge systems have a relief system to not over pressurize the enclosure. Is this some kind of metal dust that you want to keep out? Purging should work if the dust is jest airborne and not somehow forced into the cabinet.

 

[Dravik]

Well those purge systems have a relief system to not over pressurize the enclosure. Is this some kind of metal dust that you want to keep out? Purging should work if the dust is jest airborne and not somehow forced into the cabinet.

Alumina is very very fine and highly abrasive.
Raw material to make Aluminum from.

Don't think we have a cabinet here that's proof against it, Never seems to be a problem. The carbon dust on the other hand...

 

[jkerekes]

I've never had to deal with dusts, only hazardous gases and vapors. Can this stuff cause a dust explosion? What about its effects on electronics? I'm constantly amazed what some industrial equipment is sujected to and it usually works OK. I did a job where they packaged food spices. Everything was convered in cinnamon and nutmeg. Made the cabinet smell nice.

 

[leitmotif]

A small fan may suffice to slightly pressurize the cabinet with FILTERED air. Dealt with extruders and fine powder PVC with fans on the cabs and used Scotch Brite for filter media. More than likely you are going to need something that will filter out 10 micron or so particle size since sounds like you are dealing with fume also (maybe smaller).

The smaller filter pore size will require frequent changing and maybe a squirrel cage fan.

Dan Bentler

 

[Tom Jenkins]

Something like this may help.

http://www.automationdirect.com/static/specs/enccoolers.pdf

 

[leitmotif]

Vortex coolers are great IF you are willing to pay the "compressed air bill" they take a lot of air to function

Dan Bentler

 

[jkerekes]

Vortex coolers are great IF you are willing to pay the "compressed air bill" they take a lot of air to function

Dan Bentler

Compressed air ain't free. In fact it's one of the most expensive utilities that a plant has.

 

[Kent Hostetler]

One mfg. we use...

http://www.pepperl-fuchs.us/usa/en/classid_1762.htm