Method and a device for determining the flow rate of a flowing medium
AssigneeThermo Electron Corporation
InventorJörgen Lindahl
Life of this patent
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Abstract
In a method for determining the flow rate of a fluid flowing in a channel (2), the fluid being constituted by a liquid or a gas, two pulse shaped, oscillating signals are sent through the medium with one signal directed against (14) and the other signal directed with (12) the flow direction (4) of the fluid. The transmitted signals are received and the flow rate is determined by means of the phase shift between the received, pulse shaped signals caused by the flow of the fluid. The phase shift (20) between the signals is determined while compensating for the dwell time of the pulse shaped oscillating signals in the fluid.
Claims20
A method for determining a flow rate of a fluid flowing in a channel, the fluid being constituted by a liquid or a gas, comprising the steps of:
- sending from signal generators two pulse shaped, oscillating signals through the fluid at substantially the same time with one signal directed against a flow direction of the fluid and the other signal directed with the flow direction of the fluid;
- receiving the two pulse shaped, oscillating signals;
- switching the signal generators to signal receivers before the two pulse shaped, oscillating signals are received by the signal receivers, wherein the signal generators are positioned towards each other at a distance in the flow direction of the fluid;
- determining a phase shift by instantaneous phase shift measurement between the two pulse shaped, oscillating signals caused by the flow of the fluid upon receiving;
- measuring the dwell time of at least one of the two pulse shaped, oscillating signals;
- and
- determining the flow rate from the measured phase shift while compensating for the dwell time of the at least one of the two pulsed shaped, oscillating signals in the fluid.
A device for determining a flow rate of a fluid flowing in a channel, comprising:
- two signal generators for transmitting each of two pulse shaped, oscillating signals through the medium at substantially the same time, wherein one of the two pulse shaped, oscillating signals is directed against a flow direction of the fluid and the other of the two pulse shaped, oscillating signals is directed with the flow direction of the fluid, wherein the signal generators being positioned at a distance from each other in the flow direction of the fluid;
- two signal receivers, wherein the signal generators being adapted to be switched to the signal receivers before the two pulse shaped, oscillating signals are received by the signal receivers;
- means for instantaneously measuring a phase shift between the two pulse shaped, oscillating signals caused by the flow of the fluid;
- and
- means for compensating for the dwell time of at least one of the two pulse shaped, oscillating signals in the fluid when the flow rate is determined.
A device for measuring a flow rate of a fluid flowing within a channel comprising:
- two signal generators, each transmitting a pulse shaped, oscillating signal through the fluid simultaneously, each of the signal generators being arranged such that one signal generator directs one of the two pulse shaped, oscillating signals against a flow direction of the fluid, and the other signal generator directs the other of the two pulse shaped, oscillating signals with the flow direction of the fluid, wherein the signal generators being positioned at a distance from each other in the flow direction of the fluid;
- two signal receivers arranged to receive the signals from the generators, wherein the signal generators are adapted to be switched to the signal receivers before the signals are received by the signal receivers;
- and
- means for measuring the phase shift between the two pulse shaped, oscillating signals caused by the flow of the fluid;
- and
- calculating means for calculating the flow rate of the fluid on the basis of at least the measured phase shift between the two pulse shaped, oscillating signals and the dwell time of at least one of the two pulse shaped, oscillating signals.
Dependencies are inferred from the claim text.