GB349447A - - Google Patents

Abstract

349,447. Electrically-actuated valves. DEWRANCE, SiR J., 165, Great Dover Street, London. Feb. 14, 1930, No. 5049. [Class 135.] A Bourdon-tube device 5, 6, Fig. 1, for making and breaking electric circuits for controlling fluid pressure, particularly for actuating a safety valve 64 as shown in Fig. 6, is loaded by an adjustable spring 12 so that it is sensitive only beyond a pressure determined by the load. Preferably a divided tube is employed and the spring 12, which is mounted between arms 9, 10 on the ends of the tube, tends to maintain the tube in an undeformed condition with its ends against adjustable stop screws 210, 220. The ends are connected by links 34, 34 to a lever 21 pivoted at 20<1> and provided with contacts 46, 47 at its lower end. A second lever 20 located behind the first and pivoted at the same point is provided at its lower end with arms carrying adjustable contacts 54, 55. A spring 32 tends to pull the second lever to the right, so as to maintain the contact 54 thereon against the contact 46 of the first lever, and the levers move together when the Bourdon tube expands, until a stop 26 on the second lever abuts against a stop screw 27. Thereafter the first lever continues to move, under increasing pressure and the contacts 46, 54 separate, while contact is established at 47, 55. In the circuit of Fig. 6, the solenoid 67 of the blow-off valve 64 is supplied with current from mains 69, 70 through a manual switch 71, which is normally in the dotted line position but may be set to the full line position shown to open the valve independently of the automatic control. A circuit-closing solenoid S<1> and a circuit-breaking solenoid S<2> are supplied with current from a battery B under the control of the arm 21 of the pressure sensitive device, and a holding winding 81 of the solenoid S<1> is energized from the main 69, 74 while the arm 21 is at the contact 55 or moving back to the contact 54. According to the Provisional Specification, in which Specification 320,974, [Class 135, Valves &c.], is referred to, the loading by a spring weight or equivalent means may be applied to control devices responsive to temperature or other physical changes.