GB860595A - Cycling valve for the control of fluid flow - Google Patents

Abstract

860,595. Valves. JAY, K. W. May 28, 1959 [May 29, 1958], No. 18217/59. Class 135. [Also in Group XXVI] A pair of outlets 36, 39 from a valve are connectable alternately with an inlet 31 by a closure member 83 that is reciprocable in a bore 15 under the control of an auxiliary valve member 62. The valve is suitable for controlling the intermittent injection of fuel into one or more of the combustion chambers of a gas turbine engine to ignite an after burner and when so used the outlet 39 is connected to the combustion chamber and the outlet 36 to a reservoir or to the pump that feeds the inlet 31. With the parts in the positions shown, fluid entering the valve housing passes through a passage 88 in the valve member to a conduit 53 leading to a bore 16 and thence through a turbine 73 and guide vanes 74 to a conduit 52 which communicates with the outlet 36. The rotation of the turbine causes, through a screwed connection 72, axial movement of a member 75 which has abutments 77a for engagement with a lever 68 pivoted at 63 on which the valve member 62 is mounted, the lever 68 being loaded by a spring 66 which moves past a dead-centre position so that the valve member 62 is snap-acting between its open and closed positions. Thus, after a predetermined movement of the member 75 to the right the valve member 62 is moved to engage a seating 59 to interrupt flow of fluid from the bore 16 through a passage 55 leading to the left-hand end of the valve member 83. Fluid can escape from the left-hand end of the valve member 83 through a restricted passage 85 so that the valve member is then moved to the left by the pressure at the inlet 31. The outlet 36 is then closed and fluid from the inlet 31 can flow through a conduit 51, through the turbine in the reverse direction, and through grooves 77 in the member 75 to a conduit 54 which will be in communication with the outlet 39 through a reduced part 89 of the valve member 83. Due to the reversed flow through the turbine the member 75 will be returned to the position in which it opens the valve member 62 to connect the left-hand end of the main valve member 83 again with the bore 16 to cause the main valve member to be returned to the right-hand position under the influence of a spring 21. Should the movement of the member 75 towards the left fail to open the valve member 62, the continued movement of the member 75 will ultimately cause a closure member 79 to engage a seat 82 to cut off the flow to the outlet 39. In a modification, the turbine 73 is replaced by a piston that reciprocates in the bore 16 and has a direct connection with the member 75, a restriction being placed in one of the conduits leading to one side of the piston to limit the rate of movement thereof.