I’ve written before on the Principles of Operation of EXAIR products, and about how there may be more than one option to consider when choosing an engineered Compressed Air Product…here, here, and here. This may, in fact, be the most valuable service that an Application Engineer can offer a caller: providing the BEST solution, regardless of what the initial idea was. Case in point:
A caller who was familiar with our Reversible Drum Vacs’ (RDV) two-way pumping action wanted to see if he could use one for a similar purpose: they were putting a thin plastic bag liner in an open top drum, and used an electric shop vacuum to suck the air out from between the drum and liner, essentially “form fitting” the liner to the drum. Then, when they fill that liner with their product, they reverse the shop vacuum, blowing air INTO the space between the drum & liner, to assist in removing the bag. This works, but the electric vacuum is loud, and they have to move the hose from one connection to the other every time they want to put a bag in or take it out of the drum.
Like I said, the caller was familiar with our Reversible Drum Vac, so he was picturing it pulling a vacuum on the drum to pull the bag in place (when the RDV is in the “fill” position) and porting air into the drum to expel the bag (when it’s in the “empty” position.)

Thing is, the RDV needs to be installed on a drum lid, and there wouldn’t be a very effective way to port it to the space between the drum & the bag. Here’s where our attention turned to another product: the E-Vac Vacuum Generator. Same principle of operation, but easily adaptable to their specific need, because it’s, quite simply, built for adaptability.

By plumbing the vacuum port (#4 above) to a tube inserted into the drum (same as their shop vac’s hose) they can quickly pull a vacuum, which pulls the bag into place. With a valve installed on the exhaust port (#5 above,) they can close the valve to port the compressed air supply back through the vacuum line, expelling the bag. No noisy electric motor, no constantly changing the hose, just a small (Model 800005M In-Line E-Vac Low Vacuum Generator w/Muffler, in this case) compressed air operated device, with no moving parts.

If you have a need for air flow, vacuum generation, cooling, static elimination, industrial housekeeping, atomized fluid spraying, bulk material conveyance, or just questions about improving your use of your compressed air, give us a call. We’re eager to help.
Russ Bowman
Application Engineer
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