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A Pressure Regulator and Needle Valves vs. Variable Volume Control
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A traditional pressure regulator and needle valves work by filling and venting pressure of the system. This wastes a great deal of compressed gas and can introduce hysteresis error due to over-shoot and under-shoot of a test point. Because pressure regulators are designed to work with flowing gas or liquid, they work very poorly when there is no flow. A compressed gas control device such as the Ralston QTCM calibration manifold, QTVC volume controller or NPAK pressure source actually changes the volume of a closed system to control the pressure. This approach makes measurement more accurate and the calibration easier to perform. The pressure-balanced design of the QTVC and NPAK provides higher precision due to smoother operation and a larger piston diameter.
Ralston Instruments offers a wide range of digital pressure gauges for pressure calibration in the lab or in the field. From vacuum to 5000 psi, we offer an assortment of gauges for any application. Our pressure calibration kits combine a hand pump or pressure control device with the pressure gauge, hoses, adapters and gauge connections needed to perform any calibration. These complete kits include all the necessary equipment to get the job done.
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Ralston Takes to the Road
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Check us out at one of these upcoming tradeshows:
 ASGMT 2008
September 14-18 Houston TX
Booth 60
ISA Expo 2008
October 14-16 Houston TX
Booth 1748
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Did you know that you only need a small amount of o-ring lubricant on any o-ring seal. Apply the lubricant so you can feel it but cannot see it. Excess o-ring lubricant can be sucked into a pressure or vacuum check-valve and cause a false differential pressure or cause a hand pump to leak.
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