Liquid manometers with high sensitivity and small time-lag

Abstract

For some purposes a sensitive manometer is required having a small time-lag when connected to a small bore tube or orifice. The time-lag which can be tolerated is limited by the rate of change of the zero reading. Some problems in the design of a manometer with small time-lag and small rate of change of zero reading are discussed, and some general principles of design are derived. It is shown that with a null-reading inclined-tube manometer, changes of zero reading due to variation of temperature can be eliminated by correct choice of the manometer dimensions.