Patent ID: 6152178
Filing Date: 2000-11-28
Classification: F16K,F25B,Y10T

Abstract:
A four-way directional control valve for switching between flow paths formed by four pipes, characterised bya valve casing defining therein a common high pressure passage in communication with a first pipe;an isolated low pressure chamber structurally isolated from said common high pressure passage and in communication with a second pipe;a first valve seat arranged within said valve casing at a location towards one axial end thereof and formed in a communication passage between a connecting portion of a third pipe and said common high pressure passage;a second valve seat arranged within said valve casing at a location towards the other axial end thereof and formed in a communication passage between a connecting portion of a fourth pipe and said common high pressure passage;a first valve closure element arranged at a location opposite to said first valve seat within said common high pressure passage and urged in a valve closing direction;a second valve closure element arranged at a location opposite to said second valve seat within said common high pressure passage and urged in a valve closing direction;a first hollow cylindrical valve element having one inner end open to said isolated low pressure chamber and having an outer separator wall serving as one separation wall for said isolated low pressure chamber, and another axially outer end within said connecting portion of said third pipe, said first hollow cylindrical valve element being axially moveable such that said axial outer end opens and closes said first valve closure element in relation to said first valve seat;a second hollow cylindrical valve element having one inner end open to said isolated low pressure chamber and having an outer separator wall serving as another separation wall for said isolated low pressure chamber, and another axial outer end within said connecting portion of said fourth pipe, said second hollow cylindrical valve element being axially moveable such that said another axial outer end opens and closes said second valve closure element in relation to said second valve seat;a first pressure-regulating chamber defined between said separator wall and a first partition wall separating said connecting portion of said third pipe from said first pressure-regulating chamber, said first pressure-regulating chamber communicating with said isolated chamber via an orifice through said separator wall;a second pressure-regulating chamber defined between said separator wall and a second partition wall separating said connecting portion of said fourth pipe from said second pressure-regulating chamber, said second pressure-regulating chamber communicating with said isolated chamber via an orifice through said separator wall; anda pilot valve for introducing high pressure fluid pressure from said common high pressure passage into said first or second pressure-regulating chambers in a switchable manner to thereby axially move said first and second hollow cylindrical valve elements.