Area averaging ultrasonic flowmeters

Claim 2

A flowmeter cell for ultrasonically measuring the flow velocity of fluids comprising, means for containing the flowing fluid, said means having a flow channel of rectilinear internal cross section with a width dimension W and a height dimension H, said flow channel extending in a first direction normal to the plane of said rectilinear cross section for a distance at least twice the larger one of the dimension W or H; transducer means external to said flow channel for generating and sensing a beam of ultrasonic waves, said beam having a substantially uniform intensity rectilinear cross section with a width dimension W and height dimension kH where k < OR = 1, said beam being transmitted into said conduit such that it is propagated through said fluid at an oblique angle with respect to said first direction.

Claim 3

A flowmetering cell in accordance with claim 1 and including means for delivering said fluid to be measured to said flow channel to flow therethrough in said first direction.

Claim 4

A flowmetering cell in accordance with claim 2 and including means coupled to said transducer means for determining the difference in transmission of the ultrasonic waves along a path having a component in the downstream flow direction of said fluid and along a path having a component in the upstream flow direction of said fluid and providing an output signal indicative of velocity of flow of said fluid.

Claim 5

A flowmeter cell in accordance with claim 3 and including a second transducer means generating and transmitting a beam of ultrasonic energy into incidence with an interior wall of said flow channel to provide an output indication of the density of said fluid.

Claim 6

A flowmeter cell in accordance with claim 4 and including a third transducer means generating another beam of ultrasonic waves in a direction normal to said first direction to provide an output indication of the velocity of sound within said fluid.

Claim 7

A flowmeter cell in accordance with claim 5 and additionally including means for determining the attenuation of ultrasonic waves propagated through said fluid by said transducer means to provide an output indication indicative of the viscosity of said fluid.

Claim 8

A flowmeter cell in accordance with claim 1 wherein k 1.

Claim 9

A flowmeter cell in accordance with claim 7 where W H.

Claim 10

A flowmeter cell in accordance with claim 1 wherein 1 > or = k > or = 0.5.

Claim 11

A flowmeter cell for measuring the flow velocity of fluids comprising, means for containing the flowing fluid having a flow channel of rectilinear internal cross section with a width dimension W and height dimension H, said flow channel extending in a first direction normal to the plane of said rectilinear cross section, a first ultrasonic transducer mounted on one side of and external to said flow channel for emitting a beam of ultrasonic waves into the interior of said flow channel, said beam having a substantially uniform intensity rectilinear cross section with a width dimension W and a height dimension kH where k < or = 1, said beam being transmitted into said flow channel such that it propagates through said flow channel at an angle oblique with respect to said first direction, and, a second transducer means mounted on the opposite side of said flow channel and positioned to receive ultrasonic waves propagated across the interior of said flow channel at an angle parallel to the angle of propagation of the beam emitted from said first transducer.

Claim 12

A flowmeter cell for measuring the flow velocity of fluids comprising, means for containing the flowing fluid having a flow channel of rectilinear internal cross section with a width dimension W and height dimension H, said flow channel extending in a first direction normal to the plane of said rectilinear cross section, a first ultrasonic transducer mounted on one side of and external to said flow channel for emitting a beam of ultrasonic waves into the interior of said flow channel, said beam having a substantially uniform intensity rectilinear cross section with a width dimension W and a height dimension kH where k < or = 1, said beam being transmitted into said flow channel such that it propagates through said flow channel at an angle oblique with respect to said first direction, and, a second transducer means mounted on the opposite side of said flow channel and positioned to receive ultrasonic waves propagated across the interior of said flow channel at an angle parallel to the angle of propagation of the beam emitted from said first transducer.

Claim 13

A flowmeter cell in accordance with claim 10 wherein the walls of said flow channel on the sides on which said first and second transducers are mounted are formed of a first material and include cavities extending at an angle oblique to said first direction partially through said walls froM the exterior towards the interior and wherein said transducers are mounted within said cavities at the interior end thereof, the angles of said cavities being determined by the relative acoustic velocity in said first material and in the fluid to be measured such that ultrasonic waves from said first transducer are refracted at the first material-fluid interface to propagate across said flow channel at an angle with respect to said first direction, which angle lies between 10* and 60*.

Claim 14

A flowmeter cell in accordance with claim 10 wherein a pair of opposite sides of said flow channel have side channels extending therethrough from the exterior to the interior of said flow channel, each of said side channels including an insert of a first material extending from the interior orifice of said side channel partially towards the exterior of said means for containing the flowing fluid, and wherein said first and second transducers are each acoustically coupled to the outer surface of said insert in the respective side channel and wherein the angles of said side channels with respect to said first direction are determined with respect to the acoustic velocity in said insert material and the acoustic velocity in the fluid to be measured so that ultrasonic waves from said first transducer are refracted at the fluid-insert material interface at an angle with respect to said first direction between 10* and 60*.

Claim 15

A flowmeter cell in accordance with claim 10 wherein the walls of said flow channel on the sides on which said transducers are mounted are formed of a first material and each of said transducers is mounted on a wedge acoustically coupled to the wall of said flow channel, the angle of said wedge being determined with respect to the acoustic velocity in the material of said wedge, the material of said wall and said fluid material such that the emitted ultrasonic beam is refracted at the fluid-flow channel wall interface at an angle with respect to said first direction which is between 10* and 60*.

Claim 16

A flowmeter cell in accordance with claim 10 wherein the walls of said flow channel on the side where said transducers are mounted include a straight side channel extending from the exterior to the interior of said means for containing the flowing fluid, said channel having its axis at an angle equal to said oblique angle of incidence of said ultrasonic beam, each of said transducers being mounted within the respective side channels, said first transducer being mounted at an angle to emit said ultrasonic beam in a direction along the axis of said side channel.

Claim 17

An ultrasonic flow meter cell in accordance with claim 14 further including a mesh screen mounted across the inner orifice of each of said side channels.

Claim 18

A flowmeter cell in accordance with claim 14 further including a membrane mounted at the inner orifice of each of said side channels, said membrane being formed of a material and having a thickness such that it transmits a substantial portion of ultrasonic waves incident thereon, said side channels having openings to permit a portion of the fluids to be measured to pass into said side channels behind said membrane a first transducer positioned on said body external to said flow channel to emit a beam of ultrasonic waves toward said flow channel at an angle of substantially 30* with respect to said first direction, said beam having a rectilinear cross sectional area of substantially uniform intensity normal to its direction of propagation, with a width dimension W and a height dimension kH, where k < or = 1, a second transducer positioned on the same side of said flow channel as said first transducer and positioned to receive said beam of ultrasonic waves emitted from said first transducer and reflected from the wall of said flow channel opposite to the side where said first and second transducers are mounted, a section of high densitY material lining the interior wall of said flow channel in a position to intercept the beam emitted from said first transducer and reflect it toward said second transducer.

Claim 19

A flowmeter cell in accordance with claim 10 wherein said first transducer is a rectilinear piezoelectric transducer having a width dimension W and a height dimension kH.

Claim 20

A flowmeter cell in accordance with claim 10 wherein said first transducer is a circular piece of piezoelectric material having exciting electrodes attached thereto in a rectilinear configuration to produce therefrom said rectilinear shaped beam.

Claim 21

A flowmeter cell in accordance with claim 10 wherein said first transducer is coupled both to a means for exciting said transducer to emit said beam of ultrasonic waves and also to a means for detecting ultrasonic waves received by said transducer and wherein said second transducer is configured to emit a beam of ultrasonic waves having a rectilinear cross section with a width dimension W and a height dimension kH, where k < or = 1 and wherein said second transducer is coupled to a means for exciting said second transducer to emit said rectilinear shaped waves and to a means for detecting ultrasonic waves received by said second transducer.

Claim 22

A flowmeter cell for ultrasonic measuring the flow velocity of a fluid comprising, a first body having a flow channel passing therethrough, said flow channel having a rectilinear internal cross section with a width dimension W and height dimension H, said flow channel extending in a first direction normal to the plane of said cross section a distance greater than twice the larger one of said dimensions W or H, the material forming said body being an organic polymer.

Claim 23

A flowmeter cell for ultrasonic measuring the flow velocity of a fluid comprising, a first body having a flow channel passing therethrough, said flow channel having a rectilinear internal cross section with a width dimension W and height dimension H, said flow channel extending in a first direction normal to the plane of said cross section a distance greater than twice the larger one of said dimensions W or H, the material forming said body being an organic polymer.

Claim 24

A probe for measuring ultrasonically the flow velocity of fluid flowing within a conduit having a generally circular cross section comprising, first and second clamps, shaped to clamp over said conduit and to deform said conduit into a rectilinear cross section in a plane normal to the direction of flow of fluid within said conduit, said rectilinear cross section having a width W and a height H, first transducer means mounted on said clamp external to said conduit for emitting across said fluid a beam of ultrasonic waves having a substantially uniform intensity rectilinear cross section in a plane normal to the propagation of said waves, said rectilinear cross section having a width dimension W and a height dimension kH where k < or = 1; said beam of ultrasonic waves being incident upon said fluid at an angle oblique to a normal direction of flow of said fluid, and a second transducer positioned on a clamp opposite to said first clamp to receive the beam of ultrasonic waves emitted from said first transducer.

Claim 25

A probe for measuring ultrasonically the flow velocity of fluid flowing within a conduit having a generally circular cross section comprising, first and second clamps, shaped to clamp over said conduit and to deform said conduit into a rectilinear cross section in a plane normal to the direction of flow of fluid within said conduit, said rectilinear cross section having a width W and a height H, first transducer means mounted on said clamp external to said conduit for emitting across said fluid a beam of ultrasonic waves having a substantially uniform intensity rectilinear cross section in a plane normal to the propagation of said waves, said rectilinear cross section having a width dimension W and a height dimension kH where k < or = 1; said beam of ultrasonic waves being incident upon said fluid at an angle oblique to a normal direction of flow of said fluid, and a second transducer positioned on a clamp opposite to said first clamp to receive the beam of ultrasonic waves emitted from said first transducer.

Claim 26

A flowmeter cell for ultrasonically measuring the flow velocity of fluid comprising means containing said flowing fluid having a flow channel of rectilinear internal cross section with a width W and a height H, said flow channel extending in a first direction normal to the plane of said cross section a distance at least twice the larger one of the dimensions W or H, a first transducer for emitting a beam of ultrasonic waves having a substantially uniform intensity rectilinear cross section of width W and height kH where k < or = 1, said beam propagating along said flow channel on an axis which in the fluid forms an oblique angle with said first direction, the internal wall of said flow channel within the area of incidence of said ultrasonic beam emitted from said first transducer being subdivided into a series of v grooves.

Claim 27

A flowmeter cell for ultrasonically measuring the flow velocity of fluid comprising means containing said flowing fluid having a flow channel of rectilinear internal cross section with a width W and a height H, said flow channel extending in a first direction normal to the plane of said cross section a distance at least twice the larger one of the dimensions W or H, a first transducer for emitting a beam of ultrasonic waves having a substantially uniform intensity rectilinear cross section of width W and height kH where k < or = 1, said beam propagating along said flow channel on an axis which in the fluid forms an oblique angle with said first direction, the internal wall of said flow channel within the area of incidence of said ultrasonic beam emitted from said first transducer being subdivided into a series of v grooves.