Patent ID: 6255609
Filing Date: 2001-07-03
Classification: G01L,H01H

Abstract:
A pressure actuated switch mechanism for sensing low pressures within a chamber containing fluid, while resisting failure by much higher pressures, the switch mechanism comprising:a) a housing adapted for affixing to the chamber, the housing provided with sealing means for sealing against leakage of the fluid from the chamber at very high pressures;b) an internal space within the housing;c) a flexible diaphragm mounted at a first end of the internal space, the diaphragm separating the internal space from the chamber contents, the diaphragm positioned with a first face exposed to the fluid, and an opposed second face exposed to the internal space;d) a first annulus connected to the housing and having a face pressed against the first face of the diaphragm;e) a second annulus on the housing and having a diaphragm face pressed against the second face of the diaphragm, such that the diaphragm is sealingly sandwiched between the two annuli with only a center portion of the diaphragm movable;f) a cylinder fitting in the second annulus with a sliding fit and having a second end, and a first end to engage, and move with, the second face of the diaphragm as pressure is applied to the first face of the diaphragm;g) a permanent meet arranged to reciprocate within the internal space between a first, low pressure position toward the diaphragm and a second, high pressure position away from the diaphragm;h) a switch means attached to the housing at a second end of the internal space for actuation by proximity of the magnet;i) spring bias means for urging the magnet to the first position;j) means operatively connecting the second end of the cylinder to the magnet so as to cause the magnet to move with the diaphragm; andk) stop means for limiting movement of the cylinder so that its first end is aligned with the diaphragm face of the second annulus at maximum movement under the force of the diaphragm, thereby presenting a rigid surface against which the diaphragm is pressed to protect the diaphragm from damage by great pressure applied to its first face.