MagnaHelic Vacuum Gauges - A New Source
By Pat Mullarky
To all:
I've found a source of *very* good, very inexpensive Vacuum Gauges! Much to my surprise, I found that the price of a new Dwyer MagnaHelic gauge is very, very low!
To those who don't know the MagnaHelic gauge, it is a 6" diameter, 2% accuracy, *very* well built family of gauges. They are extremely sensitive, but tolerate large over-pressures.
A brand-new MagnaHelic gauge in 0-10", 0-20", 0-30", 0-40", 0-50", or 0-60" (all "water column inches" - "wci") from my local distributor was quoted at only US$ 49.95 each. These are 6-inch diameter differential pressure gauges. Many, many other ranges are available.
I found this price to be almost incredibly low! (The 30" or 60" cheaply- made bourdon-tube type gauges from the various piano supply places vary from $75 to over $100!)
Actually, I didn't really believe it, so to check it out I ordered a 0-40 wci gauge from my local distributor. Three days later, and $56.61 (sales tax added) later, I received the gauge! And, it's a true MagnaHelic, with all the extra plugs and mounting hardware! Brand new, off-the-shelf.
I now have a MagnaHelic 0-10" I got from Spencer Chase and the new MagnaHelic 0-40" teed together for pressure measurements. No need to switch gauges for low and high pressure readings. The 0-10" gauge is rated at 15 psi (around 360 wci !) over-pressure, and won't be disturbed by pressures in the 30"-40" range -- which the second gauge then displays correctly.
I should add that the MagnaHelic gauges also have a zero-adjust screw -- unlike the bourdon-type gauges which drift off zero over the years -- and aren't usually adjustable without breaking open the case.
I would say that the only drawback to the MagnaHelic gauges is that they are somewhat large. But, that's compensated for by being highly readable.
If you don't have a Dwyer distributor/representative available to you, I could possibly arrange to obtain them on order for purchase price plus tax and shipping and handling -- though I'm *not* in the retail business in any way -- and don't want to be. ...
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(Message sent Mon 26 Aug 1996, 19:15:37 GMT, from time zone GMT-0800.) |
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