Pressure sensor
First Claim
1. A fluid filled pressure transducer for measuring the pressure of an external fluid comprising:
- a sensor body having a substantially planar backup surface;
a flexible diaphragm having a radially outer portion in sealed relationship with the backup surface of the sensor body;
a variable volume fluid chamber defined by the backup surface and the diaphragm;
a sensor chamber formed in the sensor body and in fluid communication with the variable volume fluid chamber;
a pressurized, compressible working fluid contained in the fluid and sensor chambers;
means mounted in the sensor chamber for sensing variations in the density of the working fluid within the sensor chamber;
an enclosure cover attached to the sensor body and enclosing the flexible diaphragm;
an isolation diaphragm having a radially outer portion secured to said enclosure cover, said isolation diaphragm and enclosure cover forming a isolation chamber in fluid communication with said flexible diaphragm; and
a substantially incompressible isolation fluid contained in the isolation chamber whereby pressure exerted upon the isolation diaphragm is communicated by said isolation fluid to said flexible diaphragm.
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Accused Products
Abstract
A fluid filled force or pressure sensor for measuring an external force such as a fluid pressure. The apparatus includes a housing having a substantially planar backup surface, a flexible diaphragm having its radially outer portion sealed to the backup surface of the housing. A variable volume fluid chamber is formed between the backup surface and the diaphragm and is filled with a pressurized working fluid causing the diaphragm to flex outwardly away from the backup surface. The apparatus also includes a sensor chamber formed in the housing and in fluid communication with the variable volume fluid chamber. Mounted within the sensor chamber is a means for sensing variations in the density of the working fluid within the sensor chamber, such variations in density being caused by flexing of the diaphragm as a result of variations in the external pressure to be measured.
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Citations
3 Claims
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1. A fluid filled pressure transducer for measuring the pressure of an external fluid comprising:
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a sensor body having a substantially planar backup surface; a flexible diaphragm having a radially outer portion in sealed relationship with the backup surface of the sensor body; a variable volume fluid chamber defined by the backup surface and the diaphragm; a sensor chamber formed in the sensor body and in fluid communication with the variable volume fluid chamber; a pressurized, compressible working fluid contained in the fluid and sensor chambers; means mounted in the sensor chamber for sensing variations in the density of the working fluid within the sensor chamber; an enclosure cover attached to the sensor body and enclosing the flexible diaphragm; an isolation diaphragm having a radially outer portion secured to said enclosure cover, said isolation diaphragm and enclosure cover forming a isolation chamber in fluid communication with said flexible diaphragm; and a substantially incompressible isolation fluid contained in the isolation chamber whereby pressure exerted upon the isolation diaphragm is communicated by said isolation fluid to said flexible diaphragm. - View Dependent Claims (2)
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3. A pressure sensor comprising:
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a flexible diaphragm having a sufficiently high modulus of elasticity as to minimize mechanical hysteresis of the diaphragm; a body having a substantially planar backup surface in sealed relationship with the diaphragm and defining a variable volume fluid chamber between the diaphragm and the backup surface, and wherein the lower surface of the diaphragm and the backup surface are polished surfaces; a compressible working fluid contained in the fluid chamber; means for sensing variations in the density of the working fluid; and a fluid passageway means connected to said sensing means and opening to said fluid chamber for providing fluid communication between said fluid chamber and said sensing means.
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Specification