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http:// /pdfs/PB-100A%20rev-0405_Thermocouple-G-Tubes.pdf Teledyne Hastings Instruments (THI) Economy Vacuum Gauges, Models VH-3 and VH-4, are stable, dependable instruments for less demanding applications. These modular gauges feature solid-state construction with a taut-band meter and provide rapid response. The gauge tubes have excellent stability and ruggedness and provide pressure measurements over the 0-5 and 0-50 Torr ranges. Dual-scale meter faces also provide millibar readings. Environmental tests show that the gauge tube is stable over a wide temperature range. The instruments are relatively free of cable-length effects, permitting changes of cable length up to 25 feet without readjustment or recalibration. THI VH-3 and VH-4 Vacuum Gauges use a noble metal thermopile circuit. The hot junctions of the thermopile are heated directly by an AC current, while an equal number of cold junctions are kept at ambient temperature by heavy mounting studs. Thus a DC voltage is generated between hot and cold junctions. As the pressure decreases, the lowering of the thermal conductivity of the gas surrounding the hot junctions tends to increase the temperature of the hot junctions, thus increasing the output of the thermopile. We do not mark merchandise values below value or mark items as "gifts" - US and International government regulations prohibit such behavior. (Economy vacuum gauge model vh-4, 0-50 torr range was posted and is owned by: Carmen Pittman) |
Carmen-Pittman@chicagopartsnetwork.com (Carmen Pittman) for more information.
