Patent ID: 6997437
Filing Date: 2006-02-14
Classification: F02C

Abstract:
1. A valve comprising: a valve body having a bonnet receiving region and at least one flow channel; and a bonnet comprising a valve stem and a translator, at least a portion of said bonnet being positioned within said bonnet receiving region, said valve stem having a valve stem axis and being rotatable about said valve stem axis, said valve stem having valve stem threads on a valve stem threaded region, said translator having translator threads on a translator threaded region, said valve stem threads being threaded on said translator threads so that said translator can be moved from a first position to a second position by clockwise rotation of said valve stem about said valve stem axis, and said translator can be moved from said second position to said first position by counter-clockwise rotation of said valve stem about said valve stem axis, said first position being spaced from said second position in a translator motion direction which is co-linear with or substantially co-linear with said valve stem axis, at least a portion of said translator protruding into said flow channel when said translator is in at least one of said first position and said second position, whereby said translator can be positioned at a translator position selected from among said first position, said second position, or positions along said translator motion direction between said first position and said second position, such that flow through said flow channel is affected by said translator position, at least said translator threads having a coefficient of thermal expansion which is substantially similar to a coefficient of thermal expansion of said valve stem threads, said valve further comprising a gland and at least one shim, said gland being engaged with said valve body, said gland being positioned radially between said valve stem and said valve body, said valve stem having at least one protuberance extending radially outward from said valve stem, said shim being positioned axially between said protuberance and said gland, said shim thereby preventing said gland from moving axially beyond said shim.