GB190908730A - Safety-valves for Automatically Shutting Off Water-conduits when Damaged. - Google Patents

Abstract

8730. Samain, P. April 13. Valves closing with rush of fluid.-A valve, specially designed for water conduits, adapted to close should the conduit be damaged, comprises a plug lift valve 8, normally held out of engagement with its seat 26 by fluid pressure acting on a piston 6 against the action of a multiple spring 18. Fluid pressure is admitted to the cylinder 1 by passage-ways 19, 20 controlled by ball check valves 22, 23, and is exhausted, when the pressure in the conduit falls, through the hollow valve spindle 10 and spring-loaded check valves 24, 25. A balancing- piston 7 attached to the spindle 10 moves in a cylinder 5, which is closed by a plate 2 provided with perforations 15. In a modification, the combined areas of the upper and lower pistons are just greater than that of the valve, and in closing, in addition to exhausting the pressure above the upper piston, pressure is also admitted below the lower piston. In this modification, the supply to the two operating- cylinders is controlled by a distributing-valve comprising three pistons 47, 48, 49, moving in two ported cylinders 45, 46. When the pressure in the conduit falls, the pressure beneath the piston 47 is released through by-passes 61 in the seats of the ball check valves 59 and the port 42, allowing the spring 51 to move the three pistons downwards. The piston 48 then uncovers the holes 53 and covers the holes 54 to put the passage 63, which leads to the underside of the lower piston, in communication with the passage 57, instead of in communication with the outlet 64. At the same time, the piston 49 closes the passage 41, which admits the fluid pressure to the upper side of the piston 30 and uncovers the holes 55 to put this space in communication with the outlet through the " shock-absorber " B. To open the valve, the release cock 75 is opened to drain away the water trapped above the piston 47. The apparatus may be hand-operated. Shocks, preventing.-The shock-absorber B comprises a perforated tubular piston 69 moved downwards by a head 71 on a rod 70 secured to the piston 30 and moved, as the piston rises, to restrict gradually the outlet for water above the piston.