GB1332545A - Apparatus for testing pneumatic pressure transmitters - Google Patents

Abstract

1332545 Fluid pressure servomotor systems VSESOJUZNY NAUCHNO-ISSLEDOVATELSKY INSTITUT KOMITETA STANDARTOV MER I IZMERITELNYKH PRIBOROV PRI SOVETE MINISTROV SSSR 10 June 1971 19845/71 Heading G3P Apparatus for testing a pneumatic pressure transmitter 2 has a first bellows 3 fed with a variable air pressure signal from an input generator 1, and a second bellows 6 fed with the output air pressure signal from the transmitter under test, the transmitter 2 also being supplied with the input signal from the generator 1 and the bellows 3, 6 acting on a balanced pivoted arm 5 in opposite senses so that any error in the transmitter output will produce movement of the arm 5 which is recorded continuously on a twochannel recorder 13 together with the corresponding output pressure from the transmitter 2. Adjustment spring 9, and weight 16 and associated cam 17, allow adjustment of the sensitivity of the apparatus and of the balanced position of arm 5. The arm 5 carries a choke 10 which, on movement of arm 5, covers or uncovers a nozzle 11, the pressure at the nozzle being detected via pneumatic amplifier 14 to produce the output error signal which is fed to recorder 13. A further bellows 12 connected to nozzle 11 via amplifier 14 acts on arm 5 through a further pivoted arm 15 to compensate for the energy expended by bellows 3, 6 in moving the arm 5 from its balanced position. The generator Fig.2, (not shown) includes adjustable throttle valves and electric relay circuitry for increasing and decreasing the input pressure in a complete automatic testing cycle.