Abstract: A positive displacement flow meter includes a pair of smooth oval shaped rotors mounted to a pair of spaced apart rotatable shafts contained within a sealed housing. The rotatable shafts penetrate the measuring chamber and have a pair of toothed, oval shaped timing gears located in a separate gear cavity chamber which are responsible for synchronizing and maintaining the relative orientation of the smooth faced rotors with respect to one another. The fluid that is being metered forms seals between the rotating surfaces of the rotors, as well as between the rotors and the wall of rotor chamber, thus the inlet and outlet plenums are physically isolated and are consequently not in direct communication at any point during the rotation cycle of the rotors. Thus, each rotation of the rotors results in the transport of a precise and known volume of fluid from the inlet plenum to the outlet plenum.

Abstract: A flowmeter for measuring the velocity of a fluid employs a circuit for producing a magnetic field transverse to the direction of fluid velocity, thereby inducing a voltage potential in the fluid. At least two electrodes, in electrical contact with the fluid and spaced apart along a line transverse to the direction of the magnetic field and transverse to the direction of the fluid velocity, are responsive to the induced voltage potential. A signal processing circuit, that is responsive to the two electrodes, generates a velocity signal representative of the magnitude of the velocity of the fluid. A circuit periodically grounds the two electrodes, thereby eliminating any residual charge that builds up on the electrodes.

Abstract: A flowmeter for measuring the velocity of a fluid produces magnetic field transverse to the direction of fluid velocity thereby inducing a voltage potential in the fluid. The magnetic field may be produced using either electromagnets or permanent magnets. Two primary electrodes in electrical contact with the fluid, spaced apart along a first line transverse to the direction of the magnetic field and transverse to the direction of the fluid velocity sense the induced voltage potential and a background voltage across the fluid. Two secondary electrodes in electrical contact with the fluid, spaced apart along a plane parallel to the direction of the magnetic field and parallel to the direction of the fluid velocity, sense the background voltage across the fluid. A signal processor, responsive to the primary and secondary electrodes, generates a velocity signal representative of the magnitude of the velocity of the fluid.

Abstract: A strain gage flowmeter in which the sensing element is an airfoil aligned with the flow of the fluid to be measured and the flow responsive thrust on the element is transverse to the flow. This type of flowmeter can measure accurately flow in which the ratio of maximum flow to minimum flow is 100 to 1. It also reduces wear from abrasive liquids or slurries.

Abstract: Ultrasonic system for measuring fluid flow by comparing the responses from pulsed beams transmitted obliquely in opposite directions through fluid flowing in a pipe section. The transducer assembly includes a driving element comprising a piezoelectric generator in the form of a disk with a high mass backing element bonded to one face and an acoustic wave transformer bonded to the other face. The wave transformer element varies in cross-section in an axial direction, comprising disks of maximum dimension at the generator face and at the radiating face, which are separated by a connecting portion of minimum dimension. In preferred form, the wave transformer is shaped like a barbell. An advantage of this configuration is that the beam pattern is a function of frequency, having a dominant central lobe at about 45 kilocycles per second which becomes relatively depressed with respect to increasing side lobes as the frequency is increased.