Patent ID: 7975984
Filing Date: 2011-07-12
Classification: F16K

Abstract:
1. A hermetic packingless rising stem valve assembly, comprising: a valve having a body with inlet and outlet conduits defining a flow passage therethrough, a valve chamber intersecting and in fluid communication with said flow passage, and at least one valve seat mounted in said valve body having central bore surrounded by a contact face for receiving and engaging a valve element in a fluid sealing relation; said valve element disposed within said valve chamber and movable between an open position in which a fluid can flow through said flow passage between said inlet and outlet conduits, and a closed position in which said valve element is engaged with said valve seat contact face to block fluid flow between said inlet and outlet conduits; an elongate valve stem having an externally threaded portion at an upper end and a lower end connected with said valve element such that rotation of said valve stem will move said valve stem and said valve element longitudinally relative to said valve body between said open and closed positions; a valve bonnet assembly having a main body member mounted on said valve body at said valve chamber open end and an elongate tubular portion having a sidewall and an end wall defining a stem chamber that completely encloses said valve stem upper end, at least a portion of said tubular portion sidewall formed of a material so as to be relatively flexible radially inward toward said valve stem, and an outer sleeve member mounted on said main body having a sidewall surrounding said elongate tubular portion in radially spaced relation defining an annulus therebetween, said outer sleeve sidewall formed of a material so as to be relatively rigid radially, said flexible portion of said tubular portion sidewall having an internally threaded portion, the threads of said tubular portion and said external threads of said valve stem being of the same hand, of the same thread form and the same pitch; seal means disposed between said valve body and said bonnet assembly for connecting said bonnet assembly and said valve body together in fluid sealing relation wherein said valve chamber and said stem chamber are in fluid communication and sealed from the environment; a roller assembly rotatably disposed in said annulus to rotate around said main body tubular portion including a thin circular disk having a central hole therethrough which encircles said sidewall of said main body tubular portion and radially spaced holes therethrough, and a plurality of rollers each having an elongate cylindrical body with a reduced diameter neck portion at a top end rotatably received in a respective said radially spaced hole; said plurality of rollers including at least two wave generator rollers rotatably engaged on the exterior of said tubular member side wall relatively flexible portion in diametrically opposed relation to rotatably engage the exterior of said tubular portion sidewall and press said internally threaded portion radially inward to assume an elliptical configuration such that the interior threads of said tubular portion are engaged with the exterior threads of the valve stem at two diametrically opposed circumferentially spaced locations, with intermediate diametrically opposed locations of non-engagement; retaining means at an upper end of said sidewall of said the outer sleeve for retaining said roller assembly in said annulus; and rotation means connected with said roller assembly for rotating said roller assembly around said tubular portion sidewall such that upon rotation said engaged threads at two diametrically opposed circumferentially spaced locations causes relative motion axially to convert the rotary motion to linear motion thereby driving said valve stem and said valve element longitudinally between said open and closed positions.