A pressure transmitter in a process control system for transmitting pressure on a process control loop includes a transmitter housing, an isolation diaphragm configured to couple to a process fluid, and a pressure sensor body of a brittle corrosion resistant material operably coupled to the housing and positioned in the housing. The pressure sensor comprising a first portion bonded to a second portion by a fusion bond, the fusion bond substantially free of foreign material. An isolation fluid is configured to fluidically couple the pressure sensor body to the isolation diaphragm to thereby couple the pressure sensor to a pressure of the process fluid. Measurement circuitry in the transmitter housing coupled to the pressure sensor provides an output which is a function of capacitance, a loop interface in the transmitter housing coupled to the measurement circuitry configured to transmit a pressure related signal on the process control loop as a function of the pressure.
This application is continuation-in-Part of U.S. patent application Ser. No. 08/818,379, filed Mar. 14, 1997, now U.S. Pat. No. 5,731,522 and to U.S. patent application Ser. No. 09/345,165, filed Jun. 30, 1999, which is a Divisional application of Ser. No. 09/277,249, filed Mar. 26, 1999, which is a Divisional application of Ser. No. 08/807,999, filed Mar. 3, 1997, which is a Continuation application of Ser. No. 08/395,778, filed Feb. 28, 1995, now U.S. Pat. No. 5,637,802.
A high-pressure sensor comprises an inner part, a housing and a sealing system located between the inner part and the housing for sealing the high-pressure sensor. The inner part has a shaft having an end face resting, by means of a clamping force, at least along a sealing line on a support surface at a projection on the housing. Each of the projection and the shaft has an inner surface and an outer surface. The support surface is arranged in an acute angle with respect to the inner surface of the projection. The shaft by means of the clamping force is supported on the housing along a support line whereby the sealing effect can be increased with increasing pressure.
A pressure header assembly has a closed front and back surface. The back surface has an aperture for accommodating a separate dual die pressure header. The dual die pressure header has an absolute and differential pressure sensor positioned thereon. A differential pressure port is located on a side surface of the pressure header assembly and is directed to a bore in the pressure header assembly. The bore contains an elongated tube which is positioned in the pressure header assembly and locked in place by means of a crush nut and locking nut assembly. One end of the tube is coupled to the differential pressure port, while the other end of the tube accommodates a differential pressure tube which is bent in an arcuate position and directed to the underside of the sensor of the differential sensor assembly mounted in the dual die pressure header. Suitable leads from the dual die pressure header assembly are directed to a terminal board which is mounted within a pressure transducer housing shell, which terminal board coacts with an outboard contact cap assembly forming the transducer. The pressure header assembly portion also contains extending tabs which have apertures for external mounting.
A sensor apparatus and method are disclosed herein, including a sensor element located on a base and a cover located proximate to the base. The cover generally includes a sensor diaphragm and a dimple that can form a part of the cover. A flanged area or flanged portion can also be connected to the bottom portion of the cover. The flanged area provides a surface for contacting a fixture to which the sensor apparatus attaches and holding the sensor apparatus to the fixture in a manner which prevents the sensor diaphragm from contacting the fixture and inducing errors during sensor operations thereof. The cover also can include a flanged or brim-shaped portion which is connected to and surrounds the bottom portion of the cover. The flanged portion can be positioned parallel to the sensor diaphragm.
A diaphragm cover apparatus and method for a sensor are disclosed. A sensor cover is located proximate to a base. A dimple can be located centrally within the cover, wherein the dimple comprises a component that is separate from the sensor cover and diaphragm. The dimple contacts a sense element of the sensor. Additionally, a foil can be adapted for use in blocking air permeation through the sensor diaphragm, when the sensor experiences pressure. An over mold diaphragm is generally located as part of the sensor cover. The dimple itself comprises a highly polished surface to reduce stress concentrators from contacting the sense element. The dimple can be formed from materials such as stainless steel, ceramic and the like to optimize the performance of the sensor.
A pressure transducer for clean environments is disclosed. The pressure transducer includes a process coupler, a sensor module, a shield and electronics. The process coupler is configured to couple to a source of process media at a process inlet. The sensor module is coupled to the process coupler and has a pressure sensor therein. The pressure sensor has an electrical characteristic that varies in response to pressure within the sensor module. The shield is disposed adjacent to the process coupler and configured to obstruct substantially all lines of sight between the process inlet and the pressure sensor. Electronics within the transducer are coupled to the pressure sensor to measure the electrical characteristic and provide an indication thereof. A method of sensing a pressure in a clean environment is also provided.
