GB970912A - Improvements relating to fluid pressure operated control valves - Google Patents

Abstract

970,912. Valves. T. W. HAMILTON. June 11, 1963 [June 13, 1962], No. 22717/62. Heading F2V. [Also in Divisions G1 and G3] A chamber 3, Fig. 1, in an aluminium housing 1, is divided into two parts by a rubber diaphragm 4 carrying mild-steel discs 5, 6 on opposite faces thereof; the upper and lower chamber-parts are connected by ducts 7, 8 to signal and loading-pressure sources, respectively. The underside of the housing is provided with a recess 9 having an inlet duct 14 and a valve seat 16 leading to an exhaust port 15; a magnetized disc 10 within the recess 9 acts as a moving closure member relative to the seat 16. When the loading pressure exceeds the signal pressure the diaphragm 4 is urged to the position shown and the disc 10 is seated by the pressure in the duct 14. Upon the signal pressure exceeding the loading pressure the disc 6 contacts the bottom wall of the chamber 3 and the magnetized disc 10 is unseated to allow fluid from the inlet 14 to pass to the exhaust port 15. The port 15 may be normally open instead of closed and the permanent magnet may be disposed on the diaphragm and the disc 10 is then made of mild steel. The apparatus is incorporated in a concreteaggregate weighing-machine, the duct 7, Fig. 2, being tapped from a pipe between a pneumatic weighing-head 17 and a two-way valve 20 connected to a pneumatic weight-gauge 21 whilst the duct 8 leads to both a pressure regulator 23 and the valve 20. The duct 14 is connected to the actuating means of a relay valve 30 controlled by a manual valve 31 whereby a ram 29 is operated, which ram controls the outlet of a hopper 27 containing the aggregate. Specification 898,381 is referred to.