Patent GB-846105-A (GB)
Title: Improvements in or relating to fluid pressure regulators
Inventor: HOSKINS STANLEY WILLIAM
IPC: G05D16/06
Filed: 1955-10-27
Abstract: 846,105. Fluid-actuated valves. I.V. PRESSURE CONTROLLERS Ltd. Oct. 22, 1956 [Oct. 27, 1955; Jan. 16, 1956; Jan. 20, 1956], Nos. 30764/55, 1430/56 and 2040/56. Class 135. A fluid-pressure regulator of the kind comprising a valve member 9 coacting with a seat 10 and controlled by a diaphragm 15 separating a chamber at its lower side connected through a passage (not shown) with the outlet 3 from a confined space communicating through an orifice 17 with a chamber 18 containing fluid under pressure, the orifice preventing fluttering of the valve, has a safety valve connected between the outlet passage and exhaust and controlled by a diaphragm 30 separating the outlet passage from the chamber 18 so that excessive pressure in the outlet is relieved. The outlet is connected by a passage (not shown) to an annular chamber surrounding a seating 28 for the diaphragm 30, escape of excess pressure taking place through a passage 24 when the diaphragm is displaced downwardly by that pressure. The pressure at which the regulator governs is determined by the pressure in the chamber 18 which can be set as desired through needle valves 44 or 45 or through valves (not shown) communicating with the inlet 2 of the regulator. The diaphragm 30, which is backed by a rigid disc 32 and a second diaphragm 31, makes contact, when in its upper position with a ring 46 which limits the area of the diaphragm exposed to outlet pressure and therefore determines the excess pressure required in the outlet of the regulator to open the safety valve. When the diaphragm 30 is deflected a larger area of its surface is exposed to the outlet pressure so that the safety valve is not closed until a substantially lower pressure in the outlet of the regulator is reached. Rings 46 of differing internal diameters may be fitted to alter the blow-off pressure of the safety valve. In a modification, the ring 46 is omitted and adjustment of the blow-off pressure is effected by interchangeable valve seats of differing diameters. In a further embodiment a phmger acting on the diaphragm 31 and extending into the chamber 18 is urged upwardly by a spring to increase the blow-off pressure. To safeguard the diaphragm 30 in the event of high pressure in the chamber 18 a conical closure member may be provided to coact with the seating 28. A further modification consists in the provision of a fixed ring between the portions of the diaphragms 30, 31 that are clamped in the housing, the ring having a chamfered inner bore and being a close fit over the rigid disc 32 which reciprocates in its bore. The blow-off pressure can in this case be varied by substituting rings with different degrees of chamfer. Due to the fact that the valve member 9 and the diaphragm 15 are loaded upwardly by springs 42, 13 respectively, the pressure in the chamber 18 will exceed the regulated pressure as will the pressure required to deflect the diaphragm 30. To lower the latter pressure a spring may be arranged to act downwardly on the diaphragm 30 or, alternatively, the lower side of the diaphragm may be connected to a piston of less surface area than the diaphragm 30 and slidable with a gas-tight fit in a cylinder so that the pressure in the chamber acts only on its surface. To obtain greater accuracy of regulation a further embodiment is described in which the space below the valve member 9, instead of being in communication with the inlet 2 as shown, is connected by a passage through the valve member with the outlet so that the valve member is substantially balanced and independent of variations of inlet pressure. Also to minimize inaccuracy due to variations of the volume of the chamber 18 due to movement of the diaphragms the wall containing the orifice 17 is reduced in thickness and a wall containing orifices 39, 40, 41 is omitted. In the absence of this latter wall diaphragms 30, 31 carry on their lower side a bell-shaped skirt which may come into contact with the wall containing the orifice 17 to prevent excessive downward deflection of the diaphragms. Specification 846,106 is referred to.