Water Hammer Prevention Valve and Method

Abstract

A valve for preventing water hammer includes a speed reduction device for reducing a speed at which the valve may be closed. A method of preventing water hammer includes closing a valve at a fire hydrant after extracting water from the fire hydrant, in which the valve comprising a speed reduction device that increases an amount of time needed for closing the valve, and operating the valve to close the valve comprises operating the speed reduction device.

What is claimed is: 
     
         1 . A valve for preventing a fluid hammer effect, said valve comprising:
 a gate valve having a gate that is translated in and out of a channel of the valve by rotation of a valve handle; and   a speed reduction device for reducing a speed at which said valve may be closed, the speed reduction device comprising a gear train with a gear ratio such that a number of rotations of said valve handle results in a lesser number of rotations of a screw that translates said gate with respect to said channel;   wherein the gear train comprises at least three gears such that, a first two gears in the gear train reverse a direction of rotation of the valve handle as applied a third gear, the third gear again reversing a direction of rotation applied to the screw so that a clockwise rotation of the handle will close the gate and a counter-clockwise rotation of the handle will open the gate.   
     
     
         2 . The valve of  claim 1 , further comprising a set of threads at one end of the channel sized for mating with the threads of a pumper nozzle of a fire hydrant. 
     
     
         3 . The valve of  claim 2 , further comprising a set of threads at an opposite end of the channel sized for mating with a hose of a water truck. 
     
     
         4 . The valve of  claim 1 , wherein the screw comprises a worm gear. 
     
     
         5 . The valve of  claim 1 , wherein the gear train consists of three gears. 
     
     
         6 . A method of preventing a fluid hammer effect, the method comprising:
 closing a valve at a fire hydrant after extracting water from said fire hydrant, the valve comprising a gate valve having a gate that is translated in and out of a channel of the valve by rotation of a valve handle, and closing the valve comprising rotating the valve handle in a clockwise direction;   wherein the valve comprising a speed reduction device that increases an amount of time needed for closing said valve, and operating said valve to close said valve comprises operating a speed reduction device such that said increased amount of time needed for closing said valve prevents an occurrence of fluid hammer associated with said closing of said valve;   wherein the speed reduction device for reducing a speed at which said valve may be closed comprising a gear train with a gear ratio such that a number of rotations of said valve handle results in a lesser number of rotations of a screw that translates said gate with respect to said channel;   wherein the gear train comprises at least three gears such that, a first two gears in the gear train reverse a direction of rotation of the valve handle as applied a third gear, the third gear again reversing a direction of rotation applied to the screw so that a clockwise rotation of the handle will close the gate and a counter-clockwise rotation of the handle will open the gate.   
     
     
         7 . The method of  claim 6 , further comprising using a set of threads at one end of the channel sized for mating with the threads of a pumper nozzle of a fire hydrant. 
     
     
         8 . The method of  claim 7 , further comprising using a set of threads at an opposite end of the channel sized for mating with a hose of a water truck. 
     
     
         9 . The method of  claim 6 , wherein the screw comprises a worm gear. 
     
     
         10 . The method of  claim 6 , wherein the gear train consists of three gears. 
     
     
         11 . The method of  claim 6 , further comprising using the valve as an integral part of a waterline. 
     
     
         12 . The method of  claim 6 , further comprising using the valve in a line carrying petroleum. 
     
     
         13 . The method of  claim 6 , further comprising using the valve in a line carrying fluid under pressure.