FLOW DETERMINATION

• US 20160265955A1
• Filed: 02/01/2016
• Published: 09/15/2016
• Est. Priority Date: 03/13/2015
• Status: Active Grant

• Current Assignee: Centrica Hive Limited (Centrica PLC)
• Original Assignee: Flowgem Limited (Centrica PLC)
• Inventors: Easey, Peter, Griffin, David
• Granted Patent: US 10,352,745 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B25B 5/147 for pipes
• CPC Class Codes: E03B 7/071 Arrangement of safety devices in domestic pipe systems, e.g. devices for automatic shut-off
• CPC Class Codes: F17D 5/02 Preventing, monitoring, or locating loss
• CPC Class Codes: G01F 1/68 by using thermal effects
• CPC Class Codes: G01F 1/684 Structural arrangements; Mounting of elements, e.g. in relation to fluid flow
• CPC Class Codes: G01F 1/6847 where sensing or heating elements are not disturbing the fluid flow, e.g. elements mounted outside the flow duct
• CPC Class Codes: G01F 15/14 Casings, e.g. of special material
• CPC Class Codes: G01K 1/143 for measuring surface temperatures
• CPC Class Codes: G01M 3/002 by using thermal means
• CPC Class Codes: G01M 3/2807 for pipes G01M3/2892, G01M3/30 take precedence
• CPC Class Codes: Y02A 20/15 Leakage reduction or detection in water storage or distribution

Abstract

An apparatus for making a flow determination with respect to a flow through a fluid conduit such as a domestic water pipe, the fluid conduit comprising a wall having an inner surface surrounding a flow space through which the fluid flows and an outer surface, the apparatus comprising: a first temperature sensor arranged to be mounted on the outer surface of the fluid conduit and arranged to generate a first temperature signal indicative of a first temperature being the temperature of the outer surface; a second temperature sensor arranged to be positioned spaced apart from the first temperature sensor and to generate a second temperature signal indicative of a second temperature being the ambient temperature outside of the fluid conduit; and a processor having inputs for the first and second temperature signals; in which the processor has an output for the flow determination and is arranged to make the flow determination by determining a measure of the convergence of the first and second temperatures over time.

Claims

1. An apparatus for making a flow determination with respect to a flow through a fluid conduit, the fluid conduit comprising a wall having an inner surface surrounding a flow space through which the fluid flows and an outer surface, the apparatus comprising:

a first temperature sensor arranged to be mounted on the outer surface of the fluid conduit and arranged to generate a first temperature signal indicative of a first temperature being the temperature of the outer surface;

a second temperature sensor arranged to be positioned spaced apart from the first temperature sensor and to generate a second temperature signal indicative of a second temperature being the ambient temperature outside of the fluid conduit; and

a processor having inputs for the first and second temperature signals;

in which the processor has an output for the flow determination and is arranged to make the flow determination by determining a measure of the convergence of the first and second temperatures over time.

2. The apparatus of claim 1, comprising a third temperature sensor arranged to output a third temperature signal indicative of the first temperature but which is less responsive temporally than the first temperature sensor.

3. The apparatus of claim 1, comprising a housing in which the first and/or second temperature sensors are mounted, the housing supporting the first temperature sensor against the fluid conduit and optionally supports the second temperature sensor spaced away from the first temperature sensor.

4. The apparatus of claim 3, in which the housing comprises a thermal mass which holds the first temperature sensor against the fluid conduit.

5. The apparatus of claim 4, comprising a third temperature sensor arranged to output a third temperature signal indicative of the first temperature but which is less responsive temporally than the first temperature sensor, in which the third temperature sensor is provided on the thermal mass on an opposite face of the thermal mass to the first temperature sensor.

6. The apparatus of claim 3, in which the housing is provided with thermal insulation which separates the first temperature sensor on the one hand from the second temperature sensor on the other hand.

7. The apparatus of claim 1, comprising a transmitting unit which is arranged to transmit at least one of the first and second temperature signals or the flow determination to a remote location, the remote location potentially containing the processor or a remote part thereof.

8. The apparatus of claim 1, provided with at least one auxiliary set of sensors each comprising:

a first auxiliary temperature sensor arranged to be mounted on the outer surface of the fluid conduit at a different location to the first temperature sensor and arranged to generate a first auxiliary temperature signal indicative of a first auxiliary temperature being the temperature of the outer surface at the different location;

a second auxiliary temperature sensor arranged to be positioned spaced apart from the first auxiliary temperature sensor and to generate a second auxiliary temperature signal indicative of a second auxiliary temperature being the ambient temperature outside of the fluid conduit at the different location;

in which the processor has inputs for each of the first and second auxiliary temperature sensors.

9. The apparatus of claim 8, comprising a temperature differential establishing device, arranged to be placed upstream of one of the first and second temperature sensors on the one hand and an auxiliary set of sensors on the other hand, and arranged to impart a temperature differential to the fluid flowing through the fluid conduit.

10. A fluid conduit fitted with an apparatus for making a flow determination with respect to a flow through the fluid conduit, the fluid conduit comprising a wall having an inner surface surrounding a flow space through which the fluid flows and an outer surface, the apparatus comprising:

a first temperature sensor arranged to be mounted on the outer surface of the fluid conduit and arranged to generate a first temperature signal indicative of a first temperature being the temperature of the outer surface;

a second temperature sensor arranged to be positioned spaced apart from the first temperature sensor and to generate a second temperature signal indicative of a second temperature being the ambient temperature outside of the fluid conduit; and

a processor having inputs for the first and second temperature signals;

in which the processor has an output for the flow determination and is arranged to make the flow determination by determining a measure of the convergence of the first and second temperatures over time.

11. A method of making a flow determination with respect to a flow through a fluid conduit, the fluid conduit comprising a wall having an inner surface surrounding a flow space through which the fluid flows and an outer surface, the method comprising:

measuring a first temperature being the temperature of the outer surface;

measuring a second temperature being the ambient temperature outside of the fluid conduit; and

making the flow determination by determining a measure of the convergence of the first and second temperatures over time.

12. The method of claim 11, in which the determination of the measure of convergence comprises the comparison of a degree at which the first and second temperatures are converging with an expected degree, which may express the expected degree of convergence with no flow in the fluid conduit.

13. The method of claim 11, in which the determination of the measure of convergence comprises the comparison of the convergence with time of the first and second temperatures with an expected convergence curve, which typically expresses the expected convergence of the first and second temperatures with time with no flow in the fluid conduit.

14. The method of claim 11, in which the determination of the measure of convergence comprises modelling the rate of change of the first temperature with time, the rate of change of the first temperature comprising a first component which is proportional to the difference between the first and second temperatures and has a first proportionality constant, and a second component which is proportional to the difference between the first temperature and a fluid temperature, being the temperature of a fluid in the fluid conduit, and has a second proportionality constant.

15. The method of claim 11, comprising making a flow determination of a flow upstream of the first temperature sensor by determining the presence of a limit in the first temperature.

16. A sensing apparatus, comprising:

a first temperature sensor;

a sensor head housing the first temperature sensor, the sensor head being arranged so as to hold the first temperature sensor against a fluid conduit, with the first temperature sensor being arranged so as to produce in use a first temperature signal indicative of a first temperature being that of the fluid conduit;

a housing;

a second temperature sensor, arranged to produce in use a second temperature signal indicative of a second temperature being the ambient temperature;

in which the housing and the sensor head are joined by a flexible cable, the apparatus being arranged such that in use the flexible cable transmits at least one of the first and second temperature signals.

17. A kit of parts, comprising:

a first temperature sensor;

a plurality of sensor heads arranged to house the first temperature sensor, each sensor head being arranged so as to hold the first temperature sensor against a fluid conduit, with the first temperature sensor being arranged so as to produce in use a first temperature signal indicative of a first temperature being that of the fluid conduit;

a housing;

a second temperature sensor in the housing, arranged to produce in use a second temperature signal indicative of a second temperature being the ambient temperature around the housing;

in which the housing and the first temperature sensor are joined by a flexible cable, the apparatus being arranged such that in use the flexible cable transmits at least one of the first and second temperature signals and that the sensor heads can interchangeable engage the first temperature sensor.