Until now, most replacement vacuum pumps were tested under actual conditions only when they were first connected to a customer's heat treating chamber. Now, Metallurgical High Vacuum puts its new and rebuilt pumps and blowers through a torturous 'stress test' at the factory to assure performance under pump-down conditions.
As Geoff Humberstone, MHV President, comments: "We have always done a blank off test and a 20-24 hour run-in on our pumps. While this is good, using the pump to evacuate a vessel of known volume is the real acid test. We can check dynamic performance with actual pump-down times. The dynamic test verifies the CFM of the pump because you know how long it takes to reach a given vacuum level with a given volume. We can also check for excess oil out of the exhaust. Also, by monitoring the line current, we can see motor amperage under highest pump load conditions during roughing."
In all vacuum blowers, the mechanical timing is critical as the impellers must mesh exactly for dynamic sealing and pumping performance. However, some timing shift can occur during high load conditions. So blower testing requires more loading than a blank off test. By backing the blower with a 412 pump, you can 'seat the impellers'. In the case of the bypass blower, you pump down from atmosphere. This also tests the bypass valve and at the same time seats the impellers.
Dave Petersen, VP-Sales, notes: "Dynamic testing using our 'Torture Tank' gives our customers an extra margin of security that our pumps meet and exceed their performance and longevity needs, reducing their total cost of ownership. There are so many ways we can save a customer from having problems; I wonder why everyone doesn't test this way. We do and that's what is important to our customers."
Metallurgical High Vacuum has put its vacuum experience of over three decades on the line for its customers who depend on their vacuum processing systems 24/7 with reliability regardless of the original manufacturer: Stokes, Kinney, Tuthill, MD, Leybold, Dresser Roots, Aerzen, Varian, or Edwards.