Fluid flowmeter

Claim 2

A flowmeter for measuring the flow of a fluid material within a conduit comprising: an ultrasonic shear wave generator for generating ultrasonic waves in the shear mode; coupling means coupling said shear wave generator to said conduit without penetrating through said conduit at an oblique angle so that said generated shear waves are incident on the interface between said fluid and said conduit at an angle such that refracted longitudinal waves are launched into said fluid material with a substantial component of their velocity in a direction parallel to the direction of flow of said fluid; and means for measuring the variation in propagation of said longitudinal waves through a portion of said fluid stream as indicative of variations in said fluid flow rate.

Claim 3

A flowmeter for measuring the velocity of a fluid flowing within a conduit comprising: an ultrasonic shear wave generator for generating shear waves and coupling means coupled to said conduit without penetrating through said conduit for propagating said shear wave into oblique incidence with the interface between said conduit and said fluid to produce, by refraction, longitudinal waves having a substantial component of their velocity in a direction parallel to the direction of flow of said fluid, a portion of said generated longitudinal waves being propagated with a component directed opposite to the flow of said fluid and a portion of said longitudinal waves being propagated with a component in the direction of flow of said fluid; and measuring means coupled to said conduit at a position displaced from said generating means in the direction of said flow, said measuring means detecting shear waves produced in said flow, said measuring means detecting shear waves produced in said conduit by refraction of said transmitted longitudinal waves and providing an output signal indicative of the difference in transit time for said ultrasonic portions traveling with and against the direction of flow of said fluid.

Claim 4

A flowmeter for measuring the velocity of a fluid flowing within a conduit comprising: an ultrasonic shear wave generator for generating shear waves and coupling means coupled to said conduit without penetrating through said conduit for propagating said shear wave into oblique incidence with the interface between said conduit and said fluid to produce, by refraction, longitudinal waves having a substantial component of their velocity in a direction parallel to the direction of flow of said fluid, a portion of said generated longitudinal waves being propagated with a component directed opposite to the flow of said fluid and a portion of said longitudinal waves being propagated with a component in the direction of flow of said fluid; and measuring means coupled to said conduit at a position displaced from said generating means in the direction of said flow, said measuring means detecting shear waves produced in said flow, said measuring means detecting shear waves produced in said conduit by refraction of said transmitted longitudinal waves and providing an output signal indicative of the difference in transit time for said ultrasonic portions traveling with and against the direction of flow of said fluid.

Claim 5

A flowmeter in accordance with claim 2 wherein said shear wave generator is formed of a first shear wave crystal and a first coupling member, and a second shear wave crystal and a second coupling member, said first coupling member being coupled between said first shear wave crystal and said conduit, said second coupling member being coupled between said second shear waVe crystal and said conduit at a position on said conduit displaced from said first shear wave crystal in the direction of flow of said fluid, said first and second crystals being excited simultaneously to produce longitudinal waves having components in the direction of and opposite to the direction of flow of said fluid, said first and second shear wave crystals serving as sensors for said measuring means.

Claim 6

A flowmeter in accordance with claim 3 wherein said first and said second shear wave crystals are both coupled to the same side of said conduit.

Claim 7

A flowmeter in accordance with claim 3 wherein said first and said second shear wave crystals are coupled to said conduit on diagonally opposite sides of said conduit.

Claim 8

A flowmeter in accordance with claim 2 wherein said shear wave generator and said measuring means are momentarily coupled to said conduit.

Claim 9

A flowmeter in accordance with claim 2 wherein said shear wave generator is formed of at least two shear wave crystals coupled to said conduit at positions displaced from one other in the direction of flow of said fluid and wherein said shear wave crystals are simultaneously excited to produce shear waves which result in the propagation of longitudinal waves diagonally upstream and diagonally downstream across said fluid and wherein said measuring means comprises means for measuring the time difference between pulses received at said measuring means which result from the reception of ultrasonic waves transmitted downstream along said diagonal and those which have been transmitted diagonally upstream.

Claim 10

A flowmeter in accordance with claim 7 wherein said first and second shear wave crystals are excited simultaneously with several cycles of continuous wave energy and wherein said measuring means includes a phasemeter for providing an output indication of the phase difference between the pulses received at said measuring means which have been transmitted diagonally upstream and the pulses received at said measuring means which have been transmitted diagonally downstream.

Claim 11

A flowmeter in accordance with claim 7 wherein said measuring means is comprised of means for shifting the phase of a signal received from one of said diagonal paths with respect to the signal received from the other of said diagonal paths and wherein said phase-shifting means can be controlled, whereby the amount of variation in said phase-shifting means required to produce phase coincidence between said signals is indicative of the velocity of flow of said fluid material.

Claim 12

A flowmeter for measuring the velocity of a fluid flowing within a conduit comprising: an ultrasonic shear wave generator for generating shear waves; coupling means coupled to said conduit without penetrating through said conduit for propagating said generated shear waves into oblique incidence with the interface between said conduit and said fluid to produce, by refraction, longitudinal waves having a substantial component of their velocity in a direction parallel to the direction of flow of said fluid, a portion of said generated longitudinal waves being propagated with a component directed opposite to the flow of said fluid and a portion of said longitudinal waves being propagated with a component in the direction of flow of said fluid; first transducing means coupled to said conduit in a position to receive shear waves produced in said conduit by refraction from that portion of said generated longitudinal waves which was propagated with a component directed opposite to the flow of said fluid for producing output electrical signals in response to said received shear waves; a second transducing means coupled to said conduit in a position to receive shear waves produced in said conduit by refraction of that portion of said transmitted longitudinal wave which was propagated with a component in the direction of flow of said fluid for producing output electrical signals in response to said received shear waves; and means for measuring the Difference in propagation of the ultrasonic portions of the longitudinal wave traveling with and against the direction of flow of said fluid, said means for measuring the difference in propagation comprising: a phase shifter for shifting the phase of a signal received from one of said transducers with respect to the signal received from the other of said transducers, said phase shifter including a solid member, means mounted on said solid member for transmitting an ultrasonic wave along said member in response to output signals from one of said transducers, means for sensing the ultrasonic wave transmitted along said solid member and for controllably stressing said solid member, thereby varying the transit time of the transmitted ultrasonic waves along said member and output means providing an output signal indicative of the amount of stress required to produce phase coincidence between signals from the one of said transducers coupled to said phase shifter and from the other of said transducers.

Claim 13

A flowmeter for measuring the velocity of a fluid flowing within a conduit comprising: an ultrasonic shear wave generator for generating shear waves; coupling means coupled to said conduit without penetrating through said conduit for propagating said generated shear waves into oblique incidence with the interface between said conduit and said fluid to produce, by refraction, longitudinal waves having a substantial component of their velocity in a direction parallel to the direction of flow of said fluid, a portion of said generated longitudinal waves being propagated with a component directed opposite to the flow of said fluid and a portion of said longitudinal waves being propagated with a component in the direction of flow of said fluid; first transducing means coupled to said conduit in a position to receive shear waves produced in said conduit by refraction from that portion of said generated longitudinal waves which was propagated with a component directed opposite to the flow of said fluid for producing output electrical signals in response to said received shear waves; a second transducing means coupled to said conduit in a position to receive shear waves produced in said conduit by refraction of that portion of said transmitted longitudinal wave which was propagated with a component in the direction of flow of said fluid for producing output electrical signals in response to said received shear waves; and means for measuring the Difference in propagation of the ultrasonic portions of the longitudinal wave traveling with and against the direction of flow of said fluid, said means for measuring the difference in propagation comprising: a phase shifter for shifting the phase of a signal received from one of said transducers with respect to the signal received from the other of said transducers, said phase shifter including a solid member, means mounted on said solid member for transmitting an ultrasonic wave along said member in response to output signals from one of said transducers, means for sensing the ultrasonic wave transmitted along said solid member and for controllably stressing said solid member, thereby varying the transit time of the transmitted ultrasonic waves along said member and output means providing an output signal indicative of the amount of stress required to produce phase coincidence between signals from the one of said transducers coupled to said phase shifter and from the other of said transducers.

Claim 14

A flowmeter in accordance with claim 7 wherein said measuring means comprises third and fourth shear wave crystals, said third shear wave crystal being coupled to said conduit at a position diagonally opposite said first shear wave crystal and said fourth shear wave crystal being coupled to said conduit at a position diagonally opposite to said second shear wave crystal, said third and fourth shear wave crystals producing in response to longitudinal waves incident upon the adjacent section of said conduit electrical output signals.

Claim 15

A flowmeter for determining the velocity of flow of a fluid within a conduit comprising: a first shear wave generator and means coupling said first shear wave generator to said conduit without penetrating said conduit to produce at the interface of said conduit and said fluid a longitudinal wave, a substantial component of velocity of said longitudinal wave being in a direction parallel to the direction of flow of said fluid; means for exciting said shear wave generator to launch shear waves having a substantial portion of their spectral energy at a specific frequency; sensing means for sensing longitudinal waves backscattered from said fluid; and frequency detection means for measuring the difference between the frequency of the sensed backscattered waves and the frequency at which said shear waves were launched, said frequency difference providing an output indication of the velocity of flow of said fluid.

Claim 16

A flowmeter for determining the velocity of flow of a fluid within a conduit comprising: a first shear wave generator and means coupling said first shear wave generator to said conduit without penetrating said conduit to produce at the interface of said conduit and said fluid a longitudinal wave, a substantial component of velocity of said longitudinal wave being in a direction parallel to the direction of flow of said fluid; means for exciting said shear wave generator to launch shear waves having a substantial portion of their spectral energy at a specific frequency; sensing means for sensing longitudinal waves backscattered from said fluid; and frequency detection means for measuring the difference between the frequency of the sensed backscattered waves and the frequency at which said shear waves were launched, said frequency difference providing an output indication of the velocity of flow of said fluid.

Claim 17

A flowmeter in accordance with claim 12 wherein said conduit is a pipe, and wherein said longitudinal wave is launched diagonally across said pipe, and including time range gating means for actuating said sensing means at a succession of predetermined times after the excitation of said shear wave generator, each of said succession of times corresponding to a backscattering point in said fluid which occurs at a different position in said fluid stream.

Claim 18

A flowmeter in accordance with claim 13 and providing an output indication of the velocity gradient between specific radial points in said fluid stream as indicative of the viscosity of said fluid.

Claim 19

A flowmeter in accordance with claim 12 wherein said shear wave generator is formed of a first shear wave crystal coupled through a coupling wedge to said conduit and wherein said sensing means is a second shear wave crystal displaced from said first so that the sensing field of said sensing means intersects the longitudinal wave transmitted diagonally through said fluid at a predetermined radial position.

Claim 20

A flowmeter in accordance with claim 15 and including summing means for summing each of the values of flow velocity obtained for radial points across said fluid stream, and for providing appropriate weighting factors to each of said radial positions said weighting factors corresponding to the relative total area of fluid flowing at said radial positions, whereby a true total flow velocity is obtained.

Claim 21

A ultrasonic phase shifter for use in an ulTrasonic flowmeter comprising: a strip element having first and second opposed surfaces; first means for transmitting a surface wave between two predetermined points on said first surface and second means for transmitting a surface wave between two predetermined points on said second surface; means for controllably varying the stress on said strip along each of said opposing surfaces in a manner to increase the surface wave velocity on one surface while decreasing the surface wave velocity along the opposed surface, the amount of stress serving to control the phase shift between signals produced by sensors positioned to receive the respective surface waves; and means for determining the amount of stress applied to produce coincidence between signals produced by sensing the surface waves on said first surface and those produced by sensing surface waves on said opposing surfaces, and for indicating said amount of stress to indicate the amount of phase shift introduced.

Claim 22

A ultrasonic phase shifter for use in an ulTrasonic flowmeter comprising: a strip element having first and second opposed surfaces; first means for transmitting a surface wave between two predetermined points on said first surface and second means for transmitting a surface wave between two predetermined points on said second surface; means for controllably varying the stress on said strip along each of said opposing surfaces in a manner to increase the surface wave velocity on one surface while decreasing the surface wave velocity along the opposed surface, the amount of stress serving to control the phase shift between signals produced by sensors positioned to receive the respective surface waves; and means for determining the amount of stress applied to produce coincidence between signals produced by sensing the surface waves on said first surface and those produced by sensing surface waves on said opposing surfaces, and for indicating said amount of stress to indicate the amount of phase shift introduced.

Claim 23

A flowmeter in accordance with claim 13 wherein said shear wave generator is formed of a first shear wave crystal coupled through a coupling wedge to said conduit and wherein said sensing means is a second shear wave crystal displaced from said first so that the sensing field of said sensing means intersects the longitudinal wave transmitted diagonally through said fluid at a predetermined radial position.