Sensor formed from a deformation heat recoverable material having a predetermined range of temperatures in which recovery occurs and used for measuring a physical characteristic of a system

• US 5,366,292 A
• Filed: 02/01/1990
• Issued: 11/22/1994
• Est. Priority Date: 02/01/1989
• Status: Expired due to Fees

• Current Assignee: Leybold Aktiengesellschaft
• Original Assignee: Leybold Aktiengesellschaft
• Inventors: Voss, Guenter
• Primary Examiner(s): Gutierrez, Diego F. F.
• Application Number:
  US07/473,588
• Time in Patent Office: 1,755 Days
• Field of Search: 374/187, 374/188, 374/159, 374/205, 374/45, 116/219, 116/221, 116/216
• US Class Current: 374/188
• CPC Class Codes: G01K 5/483 using materials with a configuration memory, e.g. Ni-Ti alloys

Abstract

For use in a measuring and analysis instrument, a sensor including a sensor element responsive to changes in a quantity to be measured by the instrument. The sensor element is formed from a deformation heat-recoverable material having a predetermined range of temperatures in which recovery occurs. The sensor may include a control mechanism for maintaining the temperature of the sensor element substantially within the predetermined range. The sensor element forms a part of a circuit including a power source, and the control mechanism may include apparatus for selectively heating the sensor element. The sensor element is operatively connected to a signal device for sensing a physical characteristic of the sensor element and generating signals corresponding to the characteristic sensed. The signal device may include a temperature sensor, a force sensor, or a light sensor. A volt meter or ammeter may be used to measure the level of electrical energy required to maintain the sensor element at a constant temperature, thus serving as an analogue for measuring the temperature directly.

Claims

1. In a measuring instrument, a sensor including a sensor element responsive to changes in a quantity to be measured by said instrument;

wherein said sensor element is formed from a deformation heat-recoverable material having a predetermined range of temperatures in which recovery occurs; and

said sensor comprises control means for maintaining the temperature of said sensor element substantially within said predetermined range.

2. A sensor according to claim 1, wherein said sensor element forms a part of a circuit comprising a power source.

3. A sensor according to claim 2, wherein said control means comprises means for selectively heating said sensor element.

4. A sensor according to claim 3, wherein said sensor element is operatively connected to signal means for sensing a physical property of said sensor element and generating signals corresponding to said physical property.

5. A sensor according to claim 4, wherein said signal means comprises a temperature sensor.

6. A sensor according to claim 4, wherein said signal means comprises a force sensor.

7. A sensor according to claim 4, wherein said signal means comprises a voltmeter.

8. A sensor according to claim 4, wherein said signal means comprises an ammeter. .

9. A sensor according to claim 1, wherein said sensor element is formed from a two-way deformation heat-recoverable material.

10. A sensor according to claim 1, further wherein said sensor element comprises a deformation heat-recoverable wire segment, the recovery of which occurs longitudinally of said wire segment.

11. A sensor according to claim 1, further wherein said sensor element comprises a deformation heat-recoverable arcuate member defining a predetermined degree of curvature, the recovery of which occurs as a change in said degree of curvature.

12. A sensor according to claim 1, wherein said control means maintains said sensor element at a constant temperature within said temperature range.

13. A sensor according to claim 12, wherein said constant temperature lies in a lower sub-range of said temperature range.

14. A sensor according to claim 12, wherein said constant temperature lies in an upper sub-range of said temperature range.

15. A sensor according to claim 12, wherein said temperature range comprises a sub-range in which recovery of said sensor element is maximized, and further wherein said constant temperatures lies in said sub-range.

16. A method of sensing a physical characteristic of a system within a predetermined range of values, said method comprising the following steps:

providing a sensor having a sensor element formed from a deformation heat-recoverable material;

selecting said material such that it has a predetermined range of temperatures in which recovery occurs;

placing said sensor in said system;

controlling said sensor element to be maintained within said predetermined range of temperatures; and

using said sensor element to sense a physical characteristic of said system.

17. A method according to claim 16, wherein the step of controlling said sensor element comprises the following steps:

sensing a variable physical property associated with said sensor element, said physical property varying dependent upon the temperature of said sensor element;

directing a selectively variable flow of electrical energy through said sensor element at levels sufficient to maintain said sensor element at a substantially constant temperature by varying said flow of electrical energy dependent upon variations in said physical property.

18. A method according to claim 17, further comprising the step of generating signals corresponding to said levels of flow of electrical energy.

19. A method according to claim 18, further comprising the step of selecting said constant temperature to be a temperature at which recovery of said deformation heat-recoverable material begins.

20. A method according to claim 18, further comprising the step of selecting said physical property from a group consisting of temperature, density, pressure, thermal condition, gas presence, and number of ambient particles.