Minneapolis, Minn.— To help build more efficient centrifugal compressors for its chillers, McQuay International recently researched the thermodynamic state of HFC-134a refrigerant throughout the compression process at its plant in Staunton, Va. The company discovered that conventional equipment was expensive and difficult to use, but eventually found and incorporated System 9000 intelligent pressure scanners from Pressure Systems Inc. (PSI, Hampton, Va.).

PSI's microprocessor-based, multichannel devices take multiple pressure measurements in conjunction with a direct PC interface. They can also be daisy-chained and networked to form a low-cost distributed data acquisition system.

However, because these scanners had never been used in an application where they were directly exposed to a refrigerant, the two companies agreed to test PSI's Model 9010 for its ability to meet McQuay's needs. Despite the new medium, the scanners delivered accurate pressure measurements throughout the trial. This gave McQuay a new alternative to mechanical pressure scanners or discrete transducer equipment.

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