主权项 |
1. A pressure relief valve for pressure equalization between an essentially closed space and surrounding atmosphere, said pressure relief valve includes a valve housing comprising:
a cylindrical pipe section defining a wall and a flow passage, an upwardly oriented outflow, a valve seat arranged in said outflow, a valve body arranged to cooperate with said valve seat, said valve body having a drop shaped outer surface suitable for collecting gas flowing through said outflow and around said valve body to form an upwardly oriented jet, said valve body further including a downwardly oriented valve face configured for abutting said valve seat arranged in said outflow in order to define a closed state of said pressure relief valve, a stem configured for axial guidance of said valve body, and a lifting element arranged further down in said flow passage, relative to said valve seat, wherein said lifting element is connected to said valve body via said stem in order to allow said lifting element and said valve body to be moved axially as one unit between a closed state of said pressure relief valve and a state in which said pressure relief valve is open, and said pressure relief valve is configured such that the essentially closed space is, at any time, in communication with the area above said lifting element, and wherein said cylindrical pipe section further includes a flow constriction defining an essentially truncated conically shaped interior of said flow constriction, said flow constriction is configured and arranged to encircle said lifting element when said pressure relief valve is closed such that a radial passage between said lifting element and said flow constriction increase when said lifting element and said valve body is moved from a closed state of said pressure relief valve towards an open state of said pressure relief valve, and said flow constriction is provided to said cylindrical pipe section defining said wall of said valve housing as ring having an outer diameter corresponding to an inner diameter of said cylindrical pipe section. |