Self-cleaning valve and method therefor

Claim 1

A valve device comprising a valve housing having a head portion defining an opening of the valve device; a valve body disposeD in said valve housing and movable between an open and a closed position, said valve body closing said opening when in said closed position; a first resilient seal disposed on one side of said valve body; a second stationary seal disposed on the periphery of said head portion to meet said first seal when said valve body is in a closed position, said second seal defining an annular slit, storage means in said valve housing for storing cleaning fluid under pressure; said storage means being located above said annular slit and connected thereto, a control means for controlling the pressurized flow of said cleansing fluid from said storage means to said annular slit comprising a first pipe one end of which is the outlet of the storage means, a second and third pipe forming a pair of bifurcated pipes connected to the other end of said first pipe, a fourth pipe, said second and third pipes being connected to one end of said fourth pipe, the other end of said fourth pipe leading to said annular slit, said control means further comprising a first set of valves including a piston valve and a throttle valve for control of the flow of the cleaning fluid through one of the pipes of said pair and a second set of valves including a larger piston valve and a throttle valve for control of the flow of the cleaning fluid through the other pipe of said pair, said first set of valves being operatively connected to said valve body for controlling the flow of said cleaning fluid when said valve body is in its open position and said second set of valves being operative to increase the flow of said fluid when the valve body is approaching its closed position.