Piezoelectric pressure frequency sensor

Claim 2

A sensor adapted to sense a frequency of pressure fluctuations in a dynamic fluid, the sensor comprising: a sensor body having a sensor chamber including an exterior chamber opening and a solid interior chamber surface spaced opposite the opening; a transducer assembly including a piezoelectric transducer located in the sensor chamber, seated against the solid interior chamber surface, and having an end extending from the sensor chamber through and beyond the chamber opening; and a diaphragm mounted on the sensor body and sealing the chamber opening, the diaphragm being preloaded against the transducer assembly to hold the transducer assembly against the interior chamber surface in preloaded compression while the diaphragm is held in preloaded tension by the transducer assembly, and the diaphragm being formed to conform to the contour of the end of the transducer assembly and to conform to the contour of the sensor body adjacent the transducer assembly such that the diaphragm is in physical contact with the transducer assembly and the sensor body substantially completely throughout the extent of the diaphragm and such that pressure fluctuations outside the chamber against the diaphragm cause compression fluctuations in the piezoelectric transducer which cause the piezoelectric transducer to responsively generate an electrical signal representative of the frequency of the pressure fluctions.

Claim 3

A fluid pressure fluctuation frequency sensor as in claim 1, in which the diaphragm is non-vibratory to lessen fatigue.

Claim 4

A fluid pressure fluctuation frequency sensor as in claim 1, in which the diaphragm is adapted to flex only to the extent of compression in the transducer assembly, to lessen fatigue.

Claim 5

A fluid pressure fluctuation frequency sensor as in claim 1, in which the diaphragm is substantially static, to lessen fatigue.

Claim 6

A fluid pressure fluctuation frequency sensor as in claim 1, in which the transducer assembly is dry mounted in the sensor chamber.

Claim 7

A fluid pressure fluctuation frequency sensor as in claim 1, which is the product of a process of forming the diaphragm to conform to the end of the transducer assembly while the diaphragm is held in preloaded tension by the transducer assembly.

Claim 8

A fluid pressure fluctuation frequency sensor as in claim 6, in which the diaphragm is welded to the sensor body and then formed to conform to the end of the transducer assembly.

Claim 9

A fluid pressure fluctuation frequency sensor as in claim 1, in which the diaphragm is hydroformed to conform to the end of the transducer assembly.

Claim 10

A fluid pressure fluctuation frequency sensor as in claim 1 in which the transducer assembly includes a pair of electrical leads to the piezoelectric transducer, one of the electrical leads being positioned between the diaphragm and the piezoelectric transducer in direct physical contact with the diaphragm and the piezoelectric transducer, and the other of the electrical leads being positioned between the piezoelectric transducer and the interior chamber surface in direct physical contact with the piezoelectric transducer and the interior chamber surface.

Claim 11

A fluid pressure fluctuation frequency sensor as in claim 1, in which the sensor chamber is substantially cylindrical, the chamber opening, the interior chamber surface and the diaphragm are substantially circular, and the transducer assembly is substantially cylindrical.

Claim 12

A fluid pressure fluctuation frequency sensor as in claim 1, in which the sensor chamber is substantially oblate, the chamber opening, the interior chamber surface and the diaphragm are substantially oblate, and the transducer assembly is substantially oblate.

Claim 13

A sensor adapted to sense a frequency of pressure fluctuations in a dynamic fluid, the sensor comprising: a sensor body defining a sensor chamber with a central axis defining an axial direction along the central axis, and a transverse direction perpendicular to the central axis and further defining a transversely extending exterior chamber opening and a transversely extending, solid interior chamber surface spaced opposite the exterior chamber opening along the transverse direction; a diaphragm mounted on the body and sealing the exterior chamber opening; and a piezoelectric transducer assembly of at least a piezoelectric transducer having a contour surface, the piezoelectric transducer being located in the sensor chamber between the diaphragm and the solid interior chamber surface, the piezoelectric transducer being in at least indirect, rigid physical contact with the diaphragm and the interior chamber surface, the diaphragm and piezoelectric transducer being preloaded in the axial direction with the diaphragm being preloaded to hold the piezoelectric transducer assembly against the interior chamber surface in preloaded compression in the axial direction while the diaphragm is held in preloaded tension by the transducer assembly, and the diaphragm being formed to the contour of the piezoelectric transducer assembly and to conform to the contour of the sensor body adjacent the transducer assembly such that the diaphragm as in physical contact with the transducer assembly and the sensor body substantially completely throughout the extent of the diaphragm and such that, with the relative rigidities of the interior chamber surface, piezoelectric transducer and diaphragm being such that pressure fluctuations outside the sensor chamber against the diaphragm cause compression fluctuations in the piezoelectric transducer, and with the piezoelectric transducer oriented such that compression fluctuations of the piezoelectric transducer between the diaphragm and interior chamber surface cause the piezoelectric transducer to responsively generate an electrical signal related to the compression fluctuations, and thereby the pressure fluctuations.

Claim 14

A sensor adapted to sense a frequency of pressure fluctuations in a dynamic fluid, the sensor comprising: a sensor body defining a sensor chamber with a central axis defining an axial direction along the central axis, and a transverse direction perpendicular to the central axis and further defining a transversely extending exterior chamber opening and a transversely extending, solid interior chamber surface spaced opposite the exterior chamber opening along the transverse direction; a diaphragm mounted on the body and sealing the exterior chamber opening; and a piezoelectric transducer assembly of at least a piezoelectric transducer having a contour surface, the piezoelectric transducer being located in the sensor chamber between the diaphragm and the solid interior chamber surface, the piezoelectric transducer being in at least indirect, rigid physical contact with the diaphragm and the interior chamber surface, the diaphragm and piezoelectric transducer being preloaded in the axial direction with the diaphragm being preloaded to hold the piezoelectric transducer assembly against the interior chamber surface in preloaded compression in the axial direction while the diaphragm is held in preloaded tension by the transducer assembly, and the diaphragm being formed to the contour of the piezoelectric transducer assembly and to conform to the contour of the sensor body adjacent the transducer assembly such that the diaphragm as in physical contact with the transducer assembly and the sensor body substantially completely throughout the extent of the diaphragm and such that, with the relative rigidities of the interior chamber surface, piezoelectric transducer and diaphragm being such that pressure fluctuations outside the sensor chamber against the diaphragm cause compression fluctuations in the piezoelectric transducer, and with the piezoelectric transducer oriented such that compression fluctuations of the piezoelectric transducer between the diaphragm and interior chamber surface cause the piezoelectric transducer to responsively generate an electrical signal related to the compression fluctuations, and thereby the pressure fluctuations.

Claim 15

A fluid pressure fluctuation frequency sensor as in claim 12 in which the diaphragm has a central, exposed, fluid pressure receiving surface portion, the surface portion being raised in relation to the exterior chamber opening, in the axial direction away from the interior chamber surface.

Claim 16

A fluid pressure fluctuation frequency sensor as in claim 12 in which the sensor chamber has a chamber depth in the axial direction, in which the piezoelectric transducer assembly has an assembly thickness in the axial direction, and in which the assembly thickness exceeds the chamber depth.

Claim 17

A fluid pressure fluctuation frequency sensor as in claim 12 in which the piezoelectric transducer assembly is dry mounted in the sensor chamber.

Claim 18

A fluid pressure fluctuation frequency sensor as in claim 12 in which the piezoelectric transducer assembly includes a pair of electrical leads to the piezoelectric transducer, one of the electrical leads being positioned between the diaphragm and the piezoelectric transducer in direct physical contact with the diaphragm and the piezoelectric transducer, and the other of the electrical leads being positioned between the piezoelectric transducer and the interior chamber surface in direct physical contact with the piezoelectric transducer and interior chamber surface.

Claim 19

A fluid pressure fluctuation frequency sensor as in claim 16 in which the sensor chamber has a depth in the axial direction, in which the piezoelectric transducer has a transducer thickness in the axial direction, in which the electrical leads have an electrical lead thickness in the axial direction, and in which the sum of the transducer thickness and the electrical lead thickness exceeds the depth of the sensor chamber.

Claim 20

A fluid pressure fluctuation frequency sensor as in claim 16 in which the piezoelectric transducer and electrical leads are dry mounted in the sensor chamber.

Claim 21

A dynamic fluid pressure sensor as in claim 12 in which the sensor body defines a chamber wall between the exterior chamber opening and interior chamber surface, and the piezoelectric transducer has an edge, the piezoelectric transducer assembly including means for electrically insulating the piezoelectric transducer along the edge, the insulating means being mounted along the edge against the chamber wall.

Claim 22

A dynamic fluid pressure sensor as in claim 12 in which the sensor chamber is substantially cylindrical, the exterior chamber opening, interior chamber surface and diaphragm are substantially circular, and the piezoelectric transducer is a substantially cylindrical disc.

Claim 23

A dynamic fluid pressure sensor as in claim 12 in which the sensor chamber is substantially oblate, the exterior chamber opening, interior chamber surface and diaphragm are substantially oblate, and the piezoelectric transducer is a substantially oblate element.

Claim 24

In a vortex-shedding flowmeter having a bluff body generating a von Karman vortex street of two rows of vortices in a flow of fluid, and a sensor carrying body, the improvement comprising: a portion of the sensor-carrying body having at least a first side surface and defining a sensor chamber extending in a generally perpendicular direction to the side surface from the side surface into the portion, with an exterior chamber opening adjacent the side surface and an interior chamber surface opposite the exterior chamber opening, the generally perpendicular direction being an axial direction; a diaphragm mounted on the body to the side surface and sealing the exterior chamber opening; and a piezoelectric transducer assembly of at least a piezoelectric transducer, the piezoelectric transducer being located in the sensor chamber between the diaphragm and the interior chamber surface, the piezoelectric transducer being in at least indirect, rigid physical contact with the diaphragm and the interior chamber surface, the diaphragm and piezoelectric transducer being preloaded in the axial direction with the diaphragm being preloaded to hold the piezoelectric transducer assembly against the interior chamber surface in preloaded compression in the axial direction while the diaphragm is held in preloaded tension by the transducer assembly, and the diaphragm being formed to the contour of the piezoelectric transducer assembly, with the relative rigidities of the interior chamber surface, the piezoelectric transducer, and the diaphragm being such that pressure fluctuations in one of the rows of vortices outside the chamber against the diaphragm cause compression fluctuations in the piezoelectric transducer, and with the piezoelectric transducer oriented such that compression fluctuations of the interior chamber surface cause the piezoelectric transducer to generate a first electrical signal related to the compression fluctuations, and thereby the pressure fluctuations, in the one row of vortices.

Claim 25

In a vortex-shedding flowmeter having a bluff body generating a von Karman vortex street of two rows of vortices in a flow of fluid, and a sensor carrying body, the improvement comprising: a portion of the sensor-carrying body having at least a first side surface and defining a sensor chamber extending in a generally perpendicular direction to the side surface from the side surface into the portion, with an exterior chamber opening adjacent the side surface and an interior chamber surface opposite the exterior chamber opening, the generally perpendicular direction being an axial direction; a diaphragm mounted on the body to the side surface and sealing the exterior chamber opening; and a piezoelectric transducer assembly of at least a piezoelectric transducer, the piezoelectric transducer being located in the sensor chamber between the diaphragm and the interior chamber surface, the piezoelectric transducer being in at least indirect, rigid physical contact with the diaphragm and the interior chamber surface, the diaphragm and piezoelectric transducer being preloaded in the axial direction with the diaphragm being preloaded to hold the piezoelectric transducer assembly against the interior chamber surface in preloaded compression in the axial direction while the diaphragm is held in preloaded tension by the transducer assembly, and the diaphragm being formed to the contour of the piezoelectric transducer assembly, with the relative rigidities of the interior chamber surface, the piezoelectric transducer, and the diaphragm being such that pressure fluctuations in one of the rows of vortices outside the chamber against the diaphragm cause compression fluctuations in the piezoelectric transducer, and with the piezoelectric transducer oriented such that compression fluctuations of the interior chamber surface cause the piezoelectric transducer to generate a first electrical signal related to the compression fluctuations, and thereby the pressure fluctuations, in the one row of vortices.

Claim 26

The improvement in a flowmeter as in claim 22 in which the sensor chamber is a first sensor chamber, the diaphragm is a first diaphragm and the piezoelectric transducer is a first piezoelectric transducer, the improvement further comprising: the portion of the sensor-carrying body having a second side surface opposite the first side surface and defining a second sensor chamber extending in the generally perpendicular direction to the second side surface from the second side surface into the portion, with a second exterior chamber opening adjacent the second side surface and a second interior chamber surface opposite the second exterior chamber opening; a second diaphragm mounted on the body to the second side surface and sealing the second exterior chamber opening; the second piezoelectric transducer being located in the second sensor chamber between the second diaphragm and the second interior chamber surface, the second piezoelectric transducer being in at least indirect, rigid physical contact with the second diaphragm and the second interior chamber surface, the second diaphragm and second piezoelectric transducer being preloaded in the axial direction with the second diaphragm being preloaded to hold the second piezoelectric transducer assembly against the second interior surface in preloaded compression in the axial direction while the second diaphragm is held in preloaded tension by the second transducer assembly, and the second diaphragm being formed to the contour of the second piezoelectric transducer assembly with the relative rigidities of the second interior chamber surface, the second piezoelectric transducer and the second diaphragm being such that second pressure fluctuations in the second of the rows of vortices outside the second chamber against the second diaphragm cause second compression fluctuations in the second piezoelectric transducer, and with the second piezoelectric transducer oriented such that the second compression fluctuations of the second piezoelectric transducer between the second diaphragm and the second interior chamber surface cause the second piezoelectric transducer to generate a second electrical signal related to the second compression fluctuations, and thereby the second pressure fluctuations, in the second row of vortices; and means for combining the first electrical signal and the second electrical signal.

Claim 27

In a vortex-shedding flowmeter having a bluff body generating a von Karman vortex street of two rows of vortices in a flow of fluid, and a sensor carrying body, the improvement comprising: a portion of the sensor-carrying body having at least a first side surface and having a sensor chamber in the first side surface including an exterior chamber opening and an interior chamber surface spaced opposite the opening; a piezoelectric transducer assembly including a piezoelectric transducer located in the sensor chamber, seated against the interior chamber surface, and having an end extending from the sensor chamber through and beyond the exterior chamber opening; and a diaphragm mounted on the sensor body to the first side surface and sealing the exterior chamber opening, the diaphragm being preloaded against the piezoelectric transducer assembly to hold the piezoelectric transducer assembly against the interior chamber surface in preloaded compression while the diaphragm is held in preloaded tension by the piezoelectric transducer assembly, and the diaphragm being formed to conform to the end of the piezoelectric transducer assembly such that pressure fluctuations in one of the rows of vortices outside the chamber against the diaphragm cause compression fluctuations in the piezoelectric transducer which cause the piezoelectric transducer to responsively generate a first electrical signal representative of the frequency of the pressure fluctuations in the one row of vortices.

Claim 28

In a vortex-shedding flowmeter having a bluff body generating a von Karman vortex street of two rows of vortices in a flow of fluid, and a sensor carrying body, the improvement comprising: a portion of the sensor-carrying body having at least a first side surface and having a sensor chamber in the first side surface including an exterior chamber opening and an interior chamber surface spaced opposite the opening; a piezoelectric transducer assembly including a piezoelectric transducer located in the sensor chamber, seated against the interior chamber surface, and having an end extending from the sensor chamber through and beyond the exterior chamber opening; and a diaphragm mounted on the sensor body to the first side surface and sealing the exterior chamber opening, the diaphragm being preloaded against the piezoelectric transducer assembly to hold the piezoelectric transducer assembly against the interior chamber surface in preloaded compression while the diaphragm is held in preloaded tension by the piezoelectric transducer assembly, and the diaphragm being formed to conform to the end of the piezoelectric transducer assembly such that pressure fluctuations in one of the rows of vortices outside the chamber against the diaphragm cause compression fluctuations in the piezoelectric transducer which cause the piezoelectric transducer to responsively generate a first electrical signal representative of the frequency of the pressure fluctuations in the one row of vortices.

Claim 29

The improvement in a flowmeter as in claim 24 in which the sensor chamber is a first sensor chamber, the diaphragm is a first diaphragm and the transducer assembly is a first transducer assembly, the improvement further comprising: the portion of the sensor-carrying body having a second side surface opposite the first side surface and having a second sensor chamber in the second side surface including a second exterior chamber opening and a second interior chamber surface spaced opposite the second chamber opening; a second piezoelectric transducer assembly including a second piezoelectric transducer located in the second sensor chamber, seated against the second interior chamber surface, and having an end extending from the second sensor chamber through and beyond the second exterior chamber opening; and a second diaphragm mounted on the sensor body to the second side surface and sealing the second exterior chamber opening, the second diaphragm being preloaded against the second piezoelectric transducer assembly to hold the second piezoelectric transducer assembly against the second interior chamber surface in preloaded compression while the second diaphragm is held in preloaded tension by the piezoelectric transducer assembly, and the second diaphragm being formed to conform to the end of the second piezoelectric transducer assembly such that second pressure fluctuations in the second of the rows of vortices outside the second chamber against the second diaphragm cause second compression fluctuations in the second piezoelectric transducer, which cause the second piezoelectric transducer to responsively generate a second electrical signal representative of the frequency of the second pressure fluctuations in the second row of vortices; and means for combining the first electrical signal and the second electrical signal.