Temperature measurement

• US 4,876,059 A
• Filed: 07/18/1988
• Issued: 10/24/1989
• Est. Priority Date: 08/06/1987
• Status: Expired due to Fees

• Current Assignee: United Kingdom Atomic Energy Authority
• Original Assignee: United Kingdom Atomic Energy Authority
• Inventors: Conroy, Peter J.
• Primary Examiner(s): Behrend, Harvey E.
• Assistant Examiner(s): WASIL, DANIEL D
• Application Number:
  US07/219,783
• Time in Patent Office: 463 Days
• Field of Search: 376/247, 376/259, 376/252, 374/117, 374/119, 374/122, 374/124, 374/127
• US Class Current: 376/247
• CPC Class Codes: G01K 11/24 of the velocity of propagation of sound

Abstract

A method and apparatus for measuring temperature at different localized zones within a fluid medium, for example parts of the tops of fuel sub-assemblies in a reactor core, in which a continuous stress wave signal is transmitted from a remote location to targets at the zones, the frequency of the transmitted signal is progressively changed, waves reflected from the targets are received and multiplied with a reference signal, whose frequency changes at the same rate as the transmitted signal, to produce output signals wich are analyzed to derive values for the temperatures at points between the targets. A transmitter 10, target 12, receiver 14 are arranged so that oscillator 24 sweeps the transmitted signal and provides the reference signal to detector 28 which multiplies the received and reference signals and the beat frequency output signals from different targets are fed to a computer 38 for analysis.

Claims

1. A method of measuring temperature at different localised zones within a fluid medium using a high frequency stress wave energy transmitter located remotely from said zones, said method comprising:

(a) launching continuous stress waves from the transmitter through the fluid medium towards reflector targets associated with each of said zones and having known relative positions, the frequency of said transmitted stress waves being progressively changed;

(b) receiving the reflected stress waves from said targets at a receiver;

(c) multiplicatively combining the received stress waves with a reference signal whose frequency is related to that of the transmitter at the instant of reception to derive for each target a difference frequency output; and

(d) analysing said difference frequency outputs to derive values for the temperatures prevailing at locations between adjacent targets.

2. A method as claimed in claim 1, in which the reference signal is the continuous stress waves launched by the transmitter.

3. A method as claimed in claim 1, in which said targets are respectively constituted by structural parts at the tops of sub-assemblies in the core of a nuclear reactor.

4. Apparatus for measuring temperature at different localised zones within a fluid medium comprising:

(a) transmitter means located remotely from said zones for transmitting signals in the form of continuous wave, high frequency stress wave energy through said fluid medium towards reflector targets associated with said zones, the reflector targets having known relative positions;

(b) means for controlling the transmitter means to effect progressive change of the transmitted signal frequency;

(c) a reference signal source for producing a reference signal whose frequency is related to that of the transmitted signal and undergoes progressive change at the same rate as the latter;

(d) receiver means for receiving the reflected signals emanating from the reflector targets;

(e) means for multiplicatively combining each received signal with the reference signal to produce for each target a difference frequency output; and

(f) means for analysing said difference frequency outputs to derive values for the temperatures prevailing at locations between adjacent reflector targets.

5. Apparatus as claimed in claim 4, in which the reference signal is the transmitted signal.

6. In combination, a nuclear reactor comprising a core having sub-assemblies containing nuclear fuel, and apparatus for measuring temperature at different localized zones within a fluid medium comprising:

(a) transmitter means located remotely from said zones for transmitting signals in the form of continuous wave, high frequency stress wave energy through said fluid medium towards reflector targets associated with said zones, the reflector targets respectively being structural parts at the tops of said sub-assemblies and having known relative positions;

(b) means for controlling the transmitter means to effect progressive change of the transmitted signal frequency;

(c) a reference signal source for producing a reference signal whose frequency is related to that of the transmitted signal and undergoes progressive change at the same rate as the latter;

(d) receiver means for receiving the reflected signals emanating form the reflector targets;

(e) means for multiplicatively combining each received signal with the reference signal to produce for each target a difference frequency output; and

(f) means for analysing said difference frequency outputs to derive values for the temperatures prevailing at locations between adjacent reflector targets.