US 6,178,828 B2 · Free standing Coriolis driver

Abstract

A driver is provided for a Coriolis flow meter having a flow tube adapted to vibrate at a predetermined resonance frequency to determine mass flow rate of a fluid passing therethrough. The driver includes a coil, a ferromagnetic core disposed coaxially within the coil, and a spring adapted to resiliently fasten the ferromagnetic core and the coil to one another. The coil is adapted for being rigidly disposed on the flow tube and the ferromagnetic core is adapted to oscillate within the coil in response to excitation of the coil. The spring serves to guide and dampen the oscillations of the ferromagnetic core relative to the coil so that the driver is free from attachment to a non-moving object. A pivotable and/or flexible restraint may be provided to maintain the core along a curved path to centripetally accelerate the core. The driver may also be utilized as a free standing sensor in which the core is oscillated relative to the coil by vibration of the flow tube, so that the coil generates a responsive output signal.

Claims23

Dependent claims

A transducer for a Coriolis flowmeter having a flow tube vibratable at a predetermined resonance frequency to determine mass flow rate of a fluid passing therethrough, said transducer comprising:

a coil;
a ferromagnetic core disposed coaxially within said coil;
one of said coil and said ferromagnetic core being rigidly disposable on the flow tube;
said ferromagnetic core and said coil being oscillatable relative to one another in response to excitation of one of said coil and said flow tube;
a resilient member coupling said ferromagnetic core to said coil;
and
said transducer being free from attachment to a non-moving object.

4 more elements

A method for determining mass flow rate of a fluid passing through a flow tube, said method comprising the steps of:

(a) providing a driver having:
(i) a coil;
(ii) a ferromagnetic core disposed coaxially within the coil;
and
(iii) a resilient member coupling the ferromagnetic core to the coil;
(b) rigidly disposing one of the coil and the ferromagnetic core on the flow tube;
(c) maintaining the driver free from attachment to a non-moving object;
(d) applying an alternating current to the coil, wherein the ferromagnetic core and the coil are oscillated relative to one another at a predetermined frequency and the resilient member serves to constrain the oscillations of the ferromagnetic core relative to the coil, so that the driver vibrates the flow tube at a predetermined resonance frequency;
(e) disposing at least one sensor a predetermined distance from the driver on the flow tube, the at least one sensor being generating an output signal corresponding to vibration of the flow tube thereat;
and
(f) applying the output signal to a computational means to determine the mass flow rate.

8 more elements

Dependencies are inferred from the claim text.

Free standing Coriolis driver

Life of this patent

Free standing Coriolis driver

Life of this patent

Abstract

Claims23