Temperature compensated pressure limited gauge

Abstract

A temperature compensated pressure limited gauge is provided having a bourdon tube pressure sensing element. The coil is connected to a sealed cavity and has a predetermined quantity of fluid such as oil calibrated into the gauge. A solid cylinder or block of material is located within the cavity and has a relatively low volumetric thermal expansion characteristic relative to that of the fluid and of the gauge housing about the cavity. The dimensions of the block of material and housing cavity are such that their relative expansions are capable of compensating for any volumetric changes of the fluid throughout the applicable temperature range of the pressure gauge. Accordingly, a temperature compensation feature is provided that renders the pressure gauge independent of ambient thermal conditions. A fitting is included in the gauge to provide fluidic communication with the cavity. The fitting is adapted to be connected to a source of pressure to be monitored and further includes a diaphragm and a stop or limit member adjacent the diaphragm. The diaphragm separates the predetermined quantity of fluid in the pressure gauge from that of the source of pressure that is being monitored, while at the same time transmitting any changes in pressure to the fluid in the sealed cavity. The stop or limit member provides a maximum limit to the pressure that is capable of being transmitted via the diaphragm movement to the coil and thereby, protects the gauge from any destructive overload.

Dependencies are inferred from the claim text.