MANOMETERS, VACUSTATS, VACUUM GAUGES AND MANOSTATS

A frequently used simple mercury manometer which is employed for the measurement of pressure in the range 0.5-17 cm (6.6 to 226 mbar) is the U-tube design illustrated in Fig. 2.124 (Anschutz manometer, Gallenkamp). It consists of a U-tube charged with mercury and mounted in a wooden stand. The scale B, graduated in millimetres and sometimes made of mirror glass in order to eliminate errors due to parallax, is sited between the two arms and is movable. This 

Needle valves (Edwards High Vacuum) are available which provide a fine control of a gas bleed into the vacuum line, and are suitable for gas admissions 

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