US 4,422,338 A · Method and apparatus for mass flow measurement

Abstract

Apparatus and method for making fluid mass flow rate measurements using a Coriolis flow meter equipped with sensors which measure acceleration, velocity, or position of each side leg of an oscillating U-shaped conduit through which the fluid is passed. The sensors are so constructed and located as to produce analog signal outputs which accurately correspond to the motion of the respective side legs of the U-shaped conduit. When fluid is flowing through the conduit, a change from coincidence in the time relationship of the sensor signals caused by the divergent oscillations of each side leg of the U-shaped conduit is measured in both directions of oscillation. The fluid mass flow rate is then determined as a function of such time separation of the signals. The separation of the two signals with respect to time is measured without reference to static structures affixed to a platform.

Claims27

Dependent claims

In a Coriolis force mass flow rate meter including at least one continuous curved conduit solidly mounted at the open ends of leg portions thereof, which conduit is adapted to oscillate about an axis passing substantially through the mounting points of the legs, and further including mass flow rate readout means adapted to indicate mass flow rate as a function of the time delays in each direction of oscillation between the passage of one side leg of the curved conduit through a predetermined point of its oscillation and the passage of the other side leg of said conduit through a corresponding predetermined point of its oscillation, the improvement which comprises:

at least one pair of sensors, one member of each pair being mounted on opposite side legs of the conduit, the sensors being adapted to generate an analog signal linearly representative of the actual oscillatory movement of the sides of the curved conduit at the location of the respective sensor;
and
means to electronically detect the time delay between the analog sensor signals corresponding to the time difference in the passage of the opposite sides of the curved conduit through points near the mid-plane of oscillation;
whereby the magnitude of the time delay between the sensor outputs representing the time difference in passage through the mid-plane of oscillation is a measure of the mass flow rate through the curved conduit.

1 more element

In a Coriolis force meter comprising;

a continuous curved conduit having substantially symmetrical leg portions joined by a connecting yoke portion, which curved conduit is solidly supported at the open ends of the leg portions thereof for resilient oscillation of the connecting yoke portion thereof around an oscillation axis which substantially passes through both leg mounting positions;
means to oscillate the curved conduit;
and
means to measure mass flow rate as a function of deflection of the curved conduit around a Coriolis deflection axis positioned symmetrically between the legs of the curved conduit and perpendicular to the oscillation axis, by determining the time delays between passage of the opposite sides of the curved conduit through predetermined planes adjacent the mid-plane of oscillation in both directions of oscillation;
the improvement comprising improved sensor means including a pair of sensors supported at least in part by the curved conduit at positions spaced symmetrically on either side of the deflection axis, the sensors each being adapted to generate an analog signal as a linear function of the oscillatory movement of the curved conduit at the position of the sensor;
and
means to identify the time at which each sensor signal corresponds to movement of the curved conduit through a plane adjacent the mid-plane of oscillation of the curved conduit during each oscillation thereof;
whereby the mass flow rate may be accurately determined as a function of the measured time delays between the identified portions of the sensor signals.

5 more elements

In a method for measuring Coriolis forces by resiliently oscillating a continuous curved conduit which is mounted to a support at the open ends of the conduit about an axis passing substantially through the mounting position and determining mass flow rate as a function of the time delay between the passage of one side leg of the curved conduit through a predetermined position relative to the oscillation of the conduit and the passage of the other side leg of the curved conduit through a corresponding predetermined position, the improvement which comprises:

generating analog signals which are linear functions of the actual movement of the curved conduit at symmetrical positions on either side of the curved conduit;
and
determining the time delay between the signals which corresponds to the time delay of the side legs of the curved conduit passing through the predetermined positions;
whereby mass flow rate may be determined by readout means as a function of such time delay.

1 more element

Dependencies are inferred from the claim text.

Method and apparatus for mass flow measurement

Life of this patent

Method and apparatus for mass flow measurement

Life of this patent

Abstract

Claims27