High Vacuum News
Tips and Hints to Keep Your Pumps Running Strong
March, 2010 - Vol 1, Issue 1
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| Dear Reader, |
We want you to be better informed and get more from your vacuum processing system. We also want to let you know what is happening at Metallurgical High Vacuum so we may be of service. That's why we are sending you this newsletter that will let us keep in contact.
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President's Corner
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Hi, I'm Geoff Humberstone, and I've seen the vacuum business grow for over 40 years. Now, it's my turn to give back and help our colleagues. I recently made a trip back East to the Boston area in conjunction with a special project we worked on for an aerospace company that was developing a special vacuum coating chamber for the U. S. Government. It turns out they wanted a company with the expertise to make a special motion feed-through which would enable them to apply a multi-layer coating onto special mirrors for use in outer space.
They put it out for bid and we won the job, because of our experience not only in vacuum pumps but in the broader vacuum technology. They needed not only precision CNC machining, vacuum welding, fabrication with leak checking-but also the complete package. Now you might think a motion feed-through should be fairly straight-forward, but this one had unique requirements... Click Here to Read More
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| Tips & Techniques--- Avoiding Process Contamination |
Vacuum sintering of powdered materials can mean big trouble with the binders and particles landing in your vacuum pumps......here's how to avoid some problems.
When sintering powdered metals or powdered ceramics to achieve a finished state, the binding agents are driven out of the "green" parts (left in photo) under the process high heat and vacuum.
These chemicals and some particles can often get into the vacuum pumps and cause problems and pump failures. In-line traps and filters before the pumps can prevent some (not 100%) of these from reaching the pumping system.Often we recommend using.... Click Here to Read More
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| Tips and Techniques---Long Pump Down Cycle |
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When your system cycle times slow down, look for these tell tale signals of pumping system problems:
Pump oil is milky---usually caused by moisture in the pump oil. Change oil, use gas ballast to avoid future contamination.
Run the pump until it reaches operating temperature (130-140 F). Open the gas ballast valve just enough to quiet the oil slap (knocking sound). Opening more will ruin base pressure. It's a good idea to run a small amount of gas ballast all the time. Hooking up the gas ballast to a 20 psig regulated nitrogen source prevents pulling moisture-laden air into the pump.
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| Vacuum Units Conversion Chart |
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MULTIPLY
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BY
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TO GET
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mbar
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0.75
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Torr
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Torr
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1.33
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mbar
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Pa
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7.5x10-3
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Torr
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Torr
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133.00
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Pa
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CFM
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1.70
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m3/hr
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m3/hr
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0.59
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CFM
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CFM
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0.47
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l/s
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l/s
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2.12
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CFM
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| Quick Links |
Here's a short article that appeared in "Industrial Heating" last May.
"Some Straight Talk on Vacuum Pump Rebuilds"
"Many times, economic realities dictate that rebuilding your trusty Stokes, Kinney, Leybold or other brand pump makes the most sense. A rock-solid rebuild will give you many more years of profitable service before a new investment is necessary." Read Article
Please share your Vacuum Tips and Ideas. You'll get full credit when we print them! |
| Booster (Roots type) Pump Malfunctions |
Booster Pump
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With blower blanked off and running, and backing pump in good shape, you should see less than 5 millitorr at the blower inlet. If you have heavy gas ballast on the backing pump, the blower blank pressure will rise to over 10-20 millitorr. With the blower stopped, the vacuum level will also rise to around 1000 millitorr since you are trying to pump through the blower's small internal clearances.
A Pirani gage at the blower discharge should read under 50 millitorr with the blower blanked; this verifies condition of the backing pump.
Perform leak checks by connecting the helium leak detector to the blower inlet. Then introduce a small amount of helium in the gas ballast check valve on the backing pump. The helium will
"go the wrong way" and appear at the blower inlet in a few seconds. You can then check for leakage on the main shaft mechanical seals on the backing pump, interconnecting piping, blower shaft seal, blower fill/drain plugs, and don't forget the roughing valve! If you can't "see" the helium using the gas ballast valve "puff", your leak detector needs calibration/repair.
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| SPECIALS |
One of our most popular parts kits is for Stokes 412 maintenance parts. This is vacuum packed so all of the springs, gaskets, and pieces are kept together in one neat package. These are ready for immediate delivery "off the shelf". Part Number SK-412H-MNC.
A new item customers have asked for is a kit that resolves seal problems on Roots™ 6-inch blowers by replacing the original lip-type seals with precision mechanical shaft seals. The robust mechanical seals are designed to last longer and stand up to rugged operating conditions. In addition, they simplify future maintenance. Available "off the shelf".
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| Buy online at http://methivac.com/cart
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Call or write us with your questions, and let us know any suggestions and ideas you may have about the newsletter. Click to E-mail
Feel free to call on our team at MHV to help with your vacuum needs. You'll find we can respond quickly to your requests.
Sincerely,
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Metallurgical High Vacuum Corporation
6708 124th Avenue, Fennville, MI 49408-9632
Copyright (c) 2010--Metallurgical High Vacuum Corp. All rights reserved
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