The Solution To Intermittent Compressed Air System Loads

I recently had the pleasure of assisting an EXAIR Cold Gun user with an application: the parts that the Cold Guns were supposed to be cooling weren’t always getting as cool as they wanted…they’re thermistors being assembled onto a component, and they need to be below a certain temperature when they test them, so they can make sure they’re set properly. Some were getting to the test station while they were at a temperature above their setpoint, which resulted in a rejection of that part. The user wanted to know what could make the Cold Gun work better at times, and worse at other times.

The Cold Gun Aircoolant System has a Vortex Tube with a preset Cold Fraction (that’s the percentage of air supply that is directed to the cold end), so, assuming a constant compressed air supply pressure and temperature, it’ll produce the same amount of cold air flow, at the same low temperature, continuously. The user told me that they used some pneumatic tools in the area, and that these were supplied off the same header as the Cold Guns. We supposed that, during the tools’ operation (which is largely intermittent, as are the Cold Guns’), that portion of the compressed air system may be experiencing a pressure drop, possibly large enough to affect the Cold Guns’ temperature drop.

This could have resulted in a complicated re-plumbing of the compressed air supply in this area, but they were in luck…they had an unused receiver tank, and were able to install it upstream of the feed to the Cold Guns. This resulted in an undisturbed supply of air at a constant 100psig, regardless of whether, or how many, pneumatic tools were being operated at the same time in this area.

This kind of intermittent pressure drop could just as easily affect an Air Knife used for blow off (causing it to not be able to remove moisture/debris in some spots but not others), a Line Vac’s conveyance rate, an E-Vac’s suction power…and the list goes on…not to mention the reduced performance of the pneumatic tools.

If this situation sounds familiar, give us a call. We can look at your supply and demand conditions, and see if a receiver tank might be the solution. Oh, and if you don’t have one, we do: our Model 9500-60 60 Gallon Receiver Tank is ASME rated, and is ideally sized for a wide range of intermittent demands. Let us know if we can help determine if this is a viable solution for your needs.

Russ Bowman
Application Engineer
EXAIR Corporation
(513)671-3322 local
(800)923-9247 toll free
(513)671-3363 fax

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