Hermetically sealed pressure sensing device
First Claim
1. A fluid pressure sensor having an improved fluid seal comprising a capacitive pressure transducer having a first surface to be exposed to a fluid pressure to provide a capacitance value which varies with the fluid pressure applied and having transducer terminals disposed at a second opposite surface, a connector body having connector terminals therein, a housing for forming a chamber therebetween, an electrical circuit disposed in the chamber electrically connected to the transducer and connector terminals for providing an electrical signal corresponding to the applied pressure, the housing having a transducer receiving cavity defined by a bottom wall and a sidewall extending upwardly from the bottom wall, the bottom wall formed with a fluid pressure receiving recess, a fluid pressure port formed in the housing in communication with the recess, a separate thin, flexible metal diaphragm secured to the bottom wall circumscribing the recess in fluid sealing relation therewith, the transducer received in the transducer receiving cavity with the first surface overlying the bottom wall and a thin layer of plastic material disposed intermediate the first surface of the capacitive pressure transducer and the metal diaphragm in direct contract with both of them.
4 Assignments
0 Petitions
Accused Products
Abstract
A capacitive fluid pressure sensor (10, 10′, 10″) particularly adapted for use with fluids which are incompatible with conventional elastomeric fluid seals is shown in which a thin, relatively flexible metal diaphragm (18, 18′, 18″) is disposed over a fluid pressure receiving recess (16d, 16d′) formed in a bottom wall of a hexport housing (16, 16′) and hermetically attached thereto. A capacitive sensor element (12) having a pressure sensitive surface (12b) is disposed in the housing with the pressure sensitive surface placed against the metal diaphragm with a plastic intermediate layer (20, 20′, 20″, 20′″) disposed between the metal diaphragm and the sensor element to minimize hysteresis and output error. The metal diaphragm and plastic layers are shown to be flat members in certain embodiments (18, 18′ and 20, 20″) and corrugated in another embodiment (18″, 20″).
12 Citations
11 Claims
- 1. A fluid pressure sensor having an improved fluid seal comprising a capacitive pressure transducer having a first surface to be exposed to a fluid pressure to provide a capacitance value which varies with the fluid pressure applied and having transducer terminals disposed at a second opposite surface, a connector body having connector terminals therein, a housing for forming a chamber therebetween, an electrical circuit disposed in the chamber electrically connected to the transducer and connector terminals for providing an electrical signal corresponding to the applied pressure, the housing having a transducer receiving cavity defined by a bottom wall and a sidewall extending upwardly from the bottom wall, the bottom wall formed with a fluid pressure receiving recess, a fluid pressure port formed in the housing in communication with the recess, a separate thin, flexible metal diaphragm secured to the bottom wall circumscribing the recess in fluid sealing relation therewith, the transducer received in the transducer receiving cavity with the first surface overlying the bottom wall and a thin layer of plastic material disposed intermediate the first surface of the capacitive pressure transducer and the metal diaphragm in direct contract with both of them.
- 9. A fluid pressure sensor having an improved fluid seal comprising a capacitive pressure transducer having a first surface to be exposed to an applied fluid pressure to provide a capacitance value which varies with the fluid pressure applied, a housing having a transducer receiving cavity defined by a bottom wall and a sidewall extending upwardly from the bottom wall, the bottom wall formed with a fluid pressure receiving recess, a fluid pressure port formed in the housing in communication with the recess, a separate thin, flexible metal diaphragm secured to the bottom wall circumscribing the recess in fluid sealing relation therewith, the transducer received in the transducer receiving cavity with the first surface overlying the bottom wall and a thin layer of synthetic material disposed intermediate the first surface of the capacitive pressure transducer and the metal diaphragm in direct contact with both of them.
Specification