Pressure transducers

Claim 2

A transducer responsive to pressure, comprising a diaphragm having first and second opposed surfaces and a cup-shaped portion formed concentrically in said diaphragm, said cup-shaped portion having external and internal surfaces forming part of said first and second surfaces respectively of said diaphragm, means for rigidly securing said diaphragm around its periphery to define an annular portion thereof between said periphery and said cup-shaped portion, means for applying a pressure to the first said surface of the diaphragm to produce in the annular portion an area of tension stress and an area of compression stress and means disposed on said annular portion in the area of tension stress and in the area of compression stress and being responsive to the resulting axial deflection of said diaphragm for providing an indication of the applied pressure.

Claim 3

A transducer according to claim 1, in which the annular portion has an inner circumference and a periphery, and the cup-shaped portion includes a bottom wall having an outer circumference and a side wall extending concentrically between the inner circumference of the annular portion and the outer circumference of the bottom wall.

Claim 4

A transducer according to claim 2 in which the ratio of the superficial area of the cup-shaped portion to the superficial area of the annular portion is as large as practicable.

Claim 5

A transducer according to claim 3, in which said ratio is at least as great as 1:2.

Claim 6

A transducer according to claim 4 in which said ratio is approximately 3:4.

Claim 7

A transducer according to claim 1 in which the diaphragm is disposed between a first cavity and a second cavity and the cup-shaped portion extends from the annular portion into the first cavity and opens toward the annular portion into the second cavity.

Claim 8

A transducer according to claim 6 for measuring the pressure of a fluid, wherein the first cavity is provided with an inlet port for the fluid.

Claim 9

A transducer according to claim 1, in which said means responsive to axial deflection of said diaphragm comprises strain gauge means.

Claim 10

A transducer according to claim 8 wherein the means for providing an indication of the applied pressure comprises a first strain gauge so positioned on said annular portion of said diaphragm that said first strain gauge is primarily responsive to tension strain and a second strain gauge so positioned on said annular portion of said diaphragm that said second strain gauge is primarily responsive to compression strain.

Claim 11

A transducer responsive to pressure, comprising a diaphragm having a first and second opposed surfaces and a cup-shaped portion formed concentrically in said diaphragm, said cup-shaped portion having external and internal surfaces forming part of said first and second surfaces respectively of said diaphragm and including a bottom wall having an outer circumference, means for rigidly securing said diaphragm around its periphery to define an annular portion thereof between said periphery and said cup-shaped portion said annular portion having an inner circumference and a periphery, means for applying a pressure to the first said surface of the diaphragm, means disposed on said annular portion responsive to the resulting axial deflection of said diaphragm for providing an indication of the applied pressure, and an overload protection member which extends into said cup-shaped portion and has an abutment surface spaced from the internal surface of said bottom wall of said cup-shaped portion by a predetermined amount to limit deflection of the diaphragm toward the overload protection member to the said amount.

Claim 12

A transducer responsive to pressure, comprising a diaphragm having a first and second opposed surfaces and a cup-shaped portion formed concentrically in said diaphragm, said cup-shaped portion having external and internal surfaces forming part of said first and second surfaces respectively of said diaphragm and including a bottom wall having an outer circumference, means for rigidly securing said diaphragm around its periphery to define an annular portion thereof between said periphery and said cup-shaped portion said annular portion having an inner circumference and a periphery, means for applying a pressure to the first said surface of the diaphragm, means disposed on said annular portion responsive to the resulting axial deflection of said diaphragm for providing an indication of the applied pressure, and an overload protection member which extends into said cup-shaped portion and has an abutment surface spaced from the internal surface of said bottom wall of said cup-shaped portion by a predetermined amount to limit deflection of the diaphragm toward the overload protection member to the said amount.

Claim 13

A transducer according to claim 10, further comprising means for adjusting the spacing between the abutment surface and the internal base surface of the cup-shaped portion.

Claim 14

A transducer according to claim 10 in which said cup-shaped portion includes a cylinder disposed coaxially with said diaphragm.

Claim 15

A transducer for measuring the pressure of a fluid, comprising: a housing having an end wall at one end thereof and an inlet port for the fluid at the other end thereof; a diaphragm disposed internally of the housing and defining with a part of said housing including said inlet port a first cavity and defining with said end wall of the housing a second cavity, said diaphragm including: an annular portion having a generally planar configuration in an inactive state and being defined by an outer periphery and an inner circumference, the outer periphery of the annular portion being connected to the housing; a bottom wall of the diaphragm having an outer circumference and a generally planar configuration in the inactive state, the bottom wall being displaced from the plane of the annular portion in the direction of the first cavity; a side wall of the diaphragm connecting the inner circumference of the annular portion with the outer circumference of the bottom wall and forming with the bottom wall a cup-shaped portion of the diaphragm having a particular cavity opening toward the end wall of the housing into the second cavity; strain gauge means disposed on the annular portion of the diaphragm for providing an indication of the axial deflection of diaphragm when the fluid is introduced into the second cavity; and means protruding from the end wall of the housing into the second cavity and into the particular cavity of the cup-shaped portion of the diaphragm for inhibiting deflection of the bottom wall of the diaphragm beyond a predetermined distance.

Claim 16

A transducer for measuring the pressure of a fluid, comprising: a housing having an end wall at one end thereof and an inlet port for the fluid at the other end thereof; a diaphragm disposed internally of the housing and defining with a part of said housing including said inlet port a first cavity and defining with said end wall of the housing a second cavity, said diaphragm including: an annular portion having a generally planar configuration in an inactive state and being defined by an outer periphery and an inner circumference, the outer periphery of the annular portion being connected to the housing; a bottom wall of the diaphragm having an outer circumference and a generally planar configuration in the inactive state, the bottom wall being displaced from the plane of the annular portion in the direction of the first cavity; a side wall of the diaphragm connecting the inner circumference of the annular portion with the outer circumference of the bottom wall and forming with the bottom wall a cup-shaped portion of the diaphragm having a particular cavity opening toward the end wall of the housing into the second cavity; strain gauge means disposed on the annular portion of the diaphragm for providing an indication of the axial deflection of diaphragm when the fluid is introduced into the second cavity; and means protruding from the end wall of the housing into the second cavity and into the particular cavity of the cup-shaped portion of the diaphragm for inhibiting deflection of the bottom wall of the diaphragm beyond a predetermined distance.

Claim 17

The transducer recited in claim 13 wherein: deflection of the diaphragm resulting from the introduction of the fluid into the second cavity produces in the annular portion of the diaphragm a first area in compression strain and a second area in tension strain; and the strain gauge means includes a plurality of strain gauges at least one of which is disposed on the first area of the annular portion of the diaphragm and the remainder of which are disposed on the second area of the annular portion of the diaphragm.