GB854021A - Improvements in and relating to portable apparatus for testing instruments under varying pneumatic pressure conditions - Google Patents

Abstract

854,021. Barometric gauges. NORMALAIR Ltd. Feb. 23, 1959 [Feb. 21, 1958], No. 5666/58. Class 106 (2). [Also in Group XXVIII] Testing of aircraft altimeters 33, 34, Fig. 3, a rate of climb meter 35 and pressure differential gauges 36, 37 is effected in an apparatus for simulating flight conditions in an aircraft cabin pressurization system comprising a wheeled framework 2, Fig. 1, in which is mounted a motor-driven combined pressure and suction pump 12 connected through a selector valve 28 and control valves 29, 30 to reservoirs 19, 20 having pipe unions 23, 24 by which they may be connected to the instruments under test which are mounted on a panel 8 of the frame 2. The reservoirs also have pipe unions 25 which with the unions 24 are mounted on a control panel 9. In operation said reservoirs are charged to the pressure or vacuum corresponding to that found outside the aircraft and within the cabin during flight. The instruments are vibrated to prevent sticking by a member 16 which together with the pump 12 are housed in flameproof enclosures. In a modification a handoperated booster pump 50, Fig. 5 (not shown), with its own selector valve may assist the main pump or may be substituted therefor. In a still further modification the instrument 66, Fig. 9, under test is located in a transparent vacuum chamber 64 located between the wheeled framework 2 and a manometer 67.