GB813191A - Automatic plastic sealed valves - Google Patents

Abstract

813,191. Valves. BUTLER, G. A. July 26, 1956 [Aug. 29, 1955], No. 23182/56. Class 135. A valve having a gate 22 has at least one removable reservoir 29 or 30 disposed in a chamber 12 formed by the valve body and the valve bonnet 53, the reservoir lying adjacent to a valve seat 15 or 16 and a passage 90 connecting it with a passage 27 or 28 in the seat. The reservoirs contain pistons 36 below which is a lubricating and sealing plastic. The two reservoirs 29, 30, shown, may be formed from lengths of pipe or may be otherwise constructed to have an elongated cylindrical shape fitting tightly into conical recesses 32, 33 in the valve body. Reservoirs 29, 30 of different sizes may be provided for the same valve, according to the use to which it is to be put. The tops of the reservoirs 29, 30 are open to the chamber 12. When the valve gate 22 closes the fluid flow line 11, the high pressure on one side of the gate, e.g. the right-hand side of the Figure, forces the gate against the seat 15 on the lowpressure side and allows some fluid under pressure to leak past the seat 16 on the other side of the gate into the chamber 12. The pressure thus induced in the chamber 12 acts downwardly upon the tops of the pistons 36 in the reservoirs 29, 30. Since the pressure in the groove 28 of the valve seat 16 of the sealing plastic is opposed by the same pressure of the fluid leaking past it, no sealing plastic is extruded by movement of the piston. On the down-stream side of the gate 22, no equal fluid pressure opposes flow of the sealing plastic to the groove 27 in the seat 15, and accordingly the piston 36 moves downward in the reservoir 29 until sealing has been completed. Additional sealing plastic can be introduced into the reservoir 29, 30 through screw-closed bores, Fig. 2 (not shown). The chamber 12 is closed by a bonnet 53 carrying a pair of stops 44 which can engage the top of the pistons 36 and prevent their being forced out of the reservoirs 29, 30. The bonnet 53 is secured to the body of the valve by a resilient sealing ring 56, a snap-ring 59 and screws in a collar 60. In a modification, Fig. 4 (not shown), the stops 44, 45 are of a relatively short length and are made integral with the valve bonnet. Specification 700,848 is referred to.