Hi Spindoctors,
First of all, thanks to John, Alan, Rainer, Bob, Carl, Charles, Eric, Paul,
Tim, Bill, Bill, Lawrence, Greg, Robert, Ed, Patrick, Klaas, Ian, George,
Herve, Dave, and Steve for their suggestions.
I threw out all suggestions that pertained to lab humidity instead of
pressurized air dewpoint. We already have a salt indicator that turns color
when wet, but it changes too late to catch any problem early; for this
reason I ruled out any photodetector, IR, or webcam ideas. We also already
have a regular preventive maintenance regimen, but that only saves us from
end-of-life failures; it does not protect from many other factors. A
cold-trap was suggested, but that gives no direct indication of dryer
performance.
The remaining suggestions were several dewpoint sensor manufacturers, which
I list below. We have not yet made a decision on which we will use. Prices
are from ~$1,000 and higher. 2 persons recommended Xentaur, and 3
recommended Alpha.
Alpha Moisture Systems: www.amsystems.co.uk
North American Distributor: www.deltainstrument.com
Omega Engineering: www.omega.com
Kahn Companies: http://www.kahn.com/hygrometers/
Xentaur Corp.: http://www.xentaur.com/products/products.html
GE Panametrics: http://www.gesensing.com/panametricsproducts/
Shaw Moisture Meters: http://www.shawmeters.com/
There are 2 modifications we made to the dryer (recirculating dual tower
dessicant) that make it more reliable. They are putting in-line strainers
before each solenoid valve, and using spring-loaded check valves instead of
flappers. Email me if you want those details.
Cheers,
Jerry Hirschinger, NMR Instrumentation Specialist
Purdue Interdepartmental NMR Facility
560 Oval Dr. West Lafayette, IN 47907-2084
Office: Wetherill 365A
Phone / Fax: (765) 494-5288 / 494-0239
Cellular: (765) 427-3034
Received on Mon Jan 23 2006 - 18:35:05 MST