Abstract
PARTICULARS have recently been received from Messrs. W. Edwards and Co. (London), Ltd., Kangley Bridge Road, London, S.E.26, of several new devices which they manufacture for use with pumps and vacuum equipment. These include controllable leaks for the continuous admission of small quantities of gas to a vacuum system. A dial allows any particular setting of the valve to be noted and repeated. The other equipment consists of various combinations of bellows and micro-switches to form pressure-controlled relays capable of operating a half-horsepower A.o. motor. One version can be used to switch off power supplies, or start a motor, when the pressure in a vacuum system reaches any predetermined value between 15 and 500 mm. of mercury. Another application is as a safety device which comes into play when the rate of flow of liquid in a tube falls outside chosen limits. This instrument is also supplied in a form which indicates the rate of flow on a dial. No doubt many applications of these units Will be found in apparatus which has to run for long periods Without attention.
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High-Vacuum Equipment. Nature 162, 729 (1948). https://doi.org/10.1038/162729a0
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DOI: https://doi.org/10.1038/162729a0