CA2253887C - Improved surface temperature sensor and related methods - Google Patents
Improved surface temperature sensor and related methods Download PDFInfo
- Publication number
- CA2253887C CA2253887C CA 2253887 CA2253887A CA2253887C CA 2253887 C CA2253887 C CA 2253887C CA 2253887 CA2253887 CA 2253887 CA 2253887 A CA2253887 A CA 2253887A CA 2253887 C CA2253887 C CA 2253887C
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- Canada
- Prior art keywords
- shroud
- sheath
- junction
- temperature sensor
- insulation
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- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K1/00—Details of thermometers not specially adapted for particular types of thermometer
- G01K1/14—Supports; Fastening devices; Arrangements for mounting thermometers in particular locations
- G01K1/143—Supports; Fastening devices; Arrangements for mounting thermometers in particular locations for measuring surface temperatures
Abstract
A temperature sensor for measuring surface temperatures. The sensor has a metal sheath containing sheath insulation and a shroud, which has a sheath receiving end to which the sheath is welded, and a distal end at the other end of the shroud. The sheath ends at the sheath receiving end of the shroud. The shroud forms an interior cavity open on one face, with the interior cavity filled with shroud insulation. Wires extend from the sheath into the interior cavity of the shroud and terminate at a junction,. The wires are supported within the shroud by the shroud insulation. The junction is thermally insulated from the shroud and from the sheath. Preferably, the shroud insulation is ceramic cement. Preferably, the shroud has a distal end, and the junction is equidistant from the sheath receiving end and the distal end, and centered in the open face of the shroud. In one embodiment, the junction is covered by shroud insulation, for forming an ungrounded junction. In another embodiment, the shroud insulation has a boundary at the open face of the shroud, and the junction is at the boundary of the shroud insulation, for forming a grounded junction. In a further invention, the temperature sensor is clamped to the pipe.
Description
TITLE OF THE INVENTION
Improved Surface Temperature Sensor and Related Methods NAME OF INVENTOR
Neil Van Rossum FIELD OF THE INVENTION
This invention relates to surface temperature sensors, a method of making a temperature sensor and a method of securing a temperature sensor to a pipe.
BACKGROUND OF THE INVENTION
In temperature monitoring, it is relatively straightforward to provide a temperature sensor capable of measuring changes in temperature. However, when absolute temperature measurement is required, accuracy is enhanced when the temperature sensing junction of a temperature sensing device that measures the temperature at a point has the same temperature as the point would have if the temperature sensing device were not present.
Various factors affect the degree to which a temperature sensor does not disturb the temperature at the measuring point. For example, in some conventional temperature sensors used in heaters, the sheath extends well into the main body of the temperature sensor. This tends to provide a heat path for heat to affect the temperature sensing junction of the temperature sensor.
Some conventional temperature sensors have included a temperature sensing junction supported by ceramic powder in a cavity in a casing. To negate the effect that the casing has on the conduction of heat to the temperature sensing junction, the temperature sensors have been further encased in a cavity in a shroud, which itself is packed with ceramic fibers. Such a design is relatively complicated to build, and it is difficult to control the amount and density of the ceramic fiber to ensure that the temperature sensing junction at the measuring point has the same temperature as the point would have in the absence of the sensor.
The inventor has identified this problem and provided a solution as follows.
Improved Surface Temperature Sensor and Related Methods NAME OF INVENTOR
Neil Van Rossum FIELD OF THE INVENTION
This invention relates to surface temperature sensors, a method of making a temperature sensor and a method of securing a temperature sensor to a pipe.
BACKGROUND OF THE INVENTION
In temperature monitoring, it is relatively straightforward to provide a temperature sensor capable of measuring changes in temperature. However, when absolute temperature measurement is required, accuracy is enhanced when the temperature sensing junction of a temperature sensing device that measures the temperature at a point has the same temperature as the point would have if the temperature sensing device were not present.
Various factors affect the degree to which a temperature sensor does not disturb the temperature at the measuring point. For example, in some conventional temperature sensors used in heaters, the sheath extends well into the main body of the temperature sensor. This tends to provide a heat path for heat to affect the temperature sensing junction of the temperature sensor.
Some conventional temperature sensors have included a temperature sensing junction supported by ceramic powder in a cavity in a casing. To negate the effect that the casing has on the conduction of heat to the temperature sensing junction, the temperature sensors have been further encased in a cavity in a shroud, which itself is packed with ceramic fibers. Such a design is relatively complicated to build, and it is difficult to control the amount and density of the ceramic fiber to ensure that the temperature sensing junction at the measuring point has the same temperature as the point would have in the absence of the sensor.
The inventor has identified this problem and provided a solution as follows.
2 SUMMARY OF THE INVENTION
According to an aspect of the invention, there is provided a temperature sensor for measuring surface temperatures. The sensor has a metal sheath containing sheath insulation and a shroud, which has a sheath receiving end to which the sheath is welded, and a distal end at the other end of the shroud. The sheath ends at the sheath receiving end of the shroud. The shroud forms an interior cavity open on one face, with the interior cavity filled with shroud insulation. Wires extend from the sheath into the interior cavity of the shroud and terminate at a junction,. The wires are supported within the shroud by the shroud insulation. The junction is thermally and electrically insulated from the shroud and from the sheath. Preferably, the shroud insulation is ceramic cement. Preferably, the shroud has a distal end, and the junction is equidistant from the sheath receiving end and the distal end, and centered in the open face of the shroud.
In one embodiment, the junction is covered by shroud insulation, for forming an ungrounded junction. In another embodiment, the shroud insulation has a boundary at the open face of the shroud, and the junction is at the boundary of the shroud insulation, for forming a grounded junction.
A method of making a temperature sensor is also provided, along with a method of securing a temperature sensor to a pipe by clamping.
These and other aspects of the invention are described in the detailed description of the invention and claimed in the claims that follow.
BRIEF DESCRIPTION OF THE DRAWINGS
There will now be described preferred embodiments of the invention, with reference to the drawings, by way of illustration only and not with the intention of limiting the scope of the invention, in which like numerals denote like elements and in which:
Fig. I shows a section through a first embodiment of a temperature sensor according to the invention, including a shroud and sheath, Fig. 2 shows a section through a second embodiment of a temperature sensor according to the invention;
Fig. 3A is an end view of a plate for one end of the shroud;
Fig. 3B is an end view of a plate for the other end of the shroud;
According to an aspect of the invention, there is provided a temperature sensor for measuring surface temperatures. The sensor has a metal sheath containing sheath insulation and a shroud, which has a sheath receiving end to which the sheath is welded, and a distal end at the other end of the shroud. The sheath ends at the sheath receiving end of the shroud. The shroud forms an interior cavity open on one face, with the interior cavity filled with shroud insulation. Wires extend from the sheath into the interior cavity of the shroud and terminate at a junction,. The wires are supported within the shroud by the shroud insulation. The junction is thermally and electrically insulated from the shroud and from the sheath. Preferably, the shroud insulation is ceramic cement. Preferably, the shroud has a distal end, and the junction is equidistant from the sheath receiving end and the distal end, and centered in the open face of the shroud.
In one embodiment, the junction is covered by shroud insulation, for forming an ungrounded junction. In another embodiment, the shroud insulation has a boundary at the open face of the shroud, and the junction is at the boundary of the shroud insulation, for forming a grounded junction.
A method of making a temperature sensor is also provided, along with a method of securing a temperature sensor to a pipe by clamping.
These and other aspects of the invention are described in the detailed description of the invention and claimed in the claims that follow.
BRIEF DESCRIPTION OF THE DRAWINGS
There will now be described preferred embodiments of the invention, with reference to the drawings, by way of illustration only and not with the intention of limiting the scope of the invention, in which like numerals denote like elements and in which:
Fig. I shows a section through a first embodiment of a temperature sensor according to the invention, including a shroud and sheath, Fig. 2 shows a section through a second embodiment of a temperature sensor according to the invention;
Fig. 3A is an end view of a plate for one end of the shroud;
Fig. 3B is an end view of a plate for the other end of the shroud;
3 Fig. 3C is a plan view of a plate forming the casing of the shroud;
Fig. 3D is an end view of the plate of Fig. 3C after it is bent for welding to the plates shown in Figs. 3A and 3B;
Fig. 3E is an end view of a plate for forming the sheath receiving end of the shroud according to a further embodiment of the invention;
Fig. 4 shows a detail of a sheath receiving plate according to the invention;
Figs. 5A, 5B and 5C show steps towards forming an axially bent shroud;
Fig. 6 shows a tangent temperature sensor on a pipe;
Fig. 7 shows a round temperature sensor on a pipe;
Fig. 8 shows a side view of a temperature sensor on a pipe;
Fig. 9 is a section through a pipe and temperature sensor clamped to the pipe;
and Fig. 10 is a section through a pipe and a conventional temperature sensor clamped to a pipe.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Referring to Fig. 1, a temperature sensor 10 is basically formed of a shroud section and a sheath section. The sheath section is formed from a metal sheath containing sheath insulation 14, preferably mineral insulation, in which are supported wires 16, which may be for example conductive wire pairs for a thermocouple or RTD.
The shroud section is formed from a shroud 18 having a sheath receiving end 20 and a distal end 22. The sheath 12 is welded to and terminates in an adaptor sleeve 15 at the sheath receiving end 20 of the shroud 18. The shroud 18 is formed from a sheet of metal 24 bent to form an interior cavity 26 open on one face 28, as shown in Fig. 3D. The interior cavity 26 is filled with shroud insulation 30, preferably a ceramic cement.
The wires 16 extend from the sheath 12 into the interior cavity 26 of the shroud 18 and terminate at a junction 32. The wires 16 are supported within the shroud 18 by the shroud insulation 30. The junction 32 is spaced sufficiently from the sheath 12 and shroud 18 to be thermally and electrically insulated from the shroud 18 and from the sheath 12. The junction 32 is preferably located equidistant from the
Fig. 3D is an end view of the plate of Fig. 3C after it is bent for welding to the plates shown in Figs. 3A and 3B;
Fig. 3E is an end view of a plate for forming the sheath receiving end of the shroud according to a further embodiment of the invention;
Fig. 4 shows a detail of a sheath receiving plate according to the invention;
Figs. 5A, 5B and 5C show steps towards forming an axially bent shroud;
Fig. 6 shows a tangent temperature sensor on a pipe;
Fig. 7 shows a round temperature sensor on a pipe;
Fig. 8 shows a side view of a temperature sensor on a pipe;
Fig. 9 is a section through a pipe and temperature sensor clamped to the pipe;
and Fig. 10 is a section through a pipe and a conventional temperature sensor clamped to a pipe.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Referring to Fig. 1, a temperature sensor 10 is basically formed of a shroud section and a sheath section. The sheath section is formed from a metal sheath containing sheath insulation 14, preferably mineral insulation, in which are supported wires 16, which may be for example conductive wire pairs for a thermocouple or RTD.
The shroud section is formed from a shroud 18 having a sheath receiving end 20 and a distal end 22. The sheath 12 is welded to and terminates in an adaptor sleeve 15 at the sheath receiving end 20 of the shroud 18. The shroud 18 is formed from a sheet of metal 24 bent to form an interior cavity 26 open on one face 28, as shown in Fig. 3D. The interior cavity 26 is filled with shroud insulation 30, preferably a ceramic cement.
The wires 16 extend from the sheath 12 into the interior cavity 26 of the shroud 18 and terminate at a junction 32. The wires 16 are supported within the shroud 18 by the shroud insulation 30. The junction 32 is spaced sufficiently from the sheath 12 and shroud 18 to be thermally and electrically insulated from the shroud 18 and from the sheath 12. The junction 32 is preferably located equidistant from the
4 sheath receiving end 20 and the distal end 22, and is preferably centered in the open face of the shroud.
In one embodiment of the invention, shown in Fig. 2, the junction 32 is covered by shroud insulation 30, and the temperature sensor thus formed has an ungrounded junction. In another embodiment of the invention, shown in Fig. 1, the junction 32 is at the surface or boundary 36 of the shroud insulation 30 to form a grounded junction when the temperature sensor is in use.
The shroud 18 may be constructed as follows. The distal end 22 of the shroud 18 is formed from a plate 38, which may be U-shaped as shown in Fig. 3A. A
bottom edge 40 is shaped to conform to the surface to which the temperature sensor is to be attached. The sheath receiving end 20 is formed from a plate 42, with a similar U-shape and contoured bottom edge 44 as shown in Fig. 3B. A plate 24 (Fig. 3D) is bent or curved and then welded to peripheral U-shaped edges 39, 41 of each of the plates 38 and 42 to form the shroud. In an alternative embodiment, shown in Fig. 3E, the sheath receiving plate 42 (and also the plate at the distal end) has a continuous arcuate edge forming a portion of a circle. Various joints may be used to weld the plate 24 to the plates 38 and 42. One possibility is shown in Fig. 4, in which plate 42 has an annular lip 48 which the plate 24 slides over into abutment with the shoulder 50. The shroud 18 may be fitted to a curved surface, as for example the surface of a pipe shaped like a large helix or coil, by curving the plate 24 as shown in Figs. 5A-5C.
First, slots 52 are cut into the plate 24 at intervals. The slots are perpendicular to the shroud axis A. Second, the plate 24 is bent to close the slots 52 at their open ends.
Third, the slots 52 are welded solid.
The shroud 18 may be attached to a pipe 54 as illustrated in Figs. 6, 7 and 8, for a U-shape or tangent shape (Fig. 6) and round shape (Fig. 7). The shroud 18 is firmly secured to the pipe 54 by welding both longitudinal edges 56 of the shroud, the bottom edges 60 of the sheath adaptor 15, and the bottom edges of the plates 38 and 42 to the pipe 54. The welds are completed in conventional manner. The sheath is not welded to the pipe. Preferably, the cavity is packed with ceramic cement during manufacturing, and not at the site where the temperature sensor is to be used.
With the temperature sensing junction centered in the cavity, and with a single metal shroud packed with ceramic cement, known techniques may be used to ensure that the temperature sensing junction senses the same temperature at the measuring point as if the temperature sensor were not there. Preferably, this is carried out by finite element analysis. The factors affecting the temperature at the measuring point include the diameter and length of the cavity 30, the thermal conductivity of the materials used, the wall thickness of the shroud, the size of the weld used to secure the
In one embodiment of the invention, shown in Fig. 2, the junction 32 is covered by shroud insulation 30, and the temperature sensor thus formed has an ungrounded junction. In another embodiment of the invention, shown in Fig. 1, the junction 32 is at the surface or boundary 36 of the shroud insulation 30 to form a grounded junction when the temperature sensor is in use.
The shroud 18 may be constructed as follows. The distal end 22 of the shroud 18 is formed from a plate 38, which may be U-shaped as shown in Fig. 3A. A
bottom edge 40 is shaped to conform to the surface to which the temperature sensor is to be attached. The sheath receiving end 20 is formed from a plate 42, with a similar U-shape and contoured bottom edge 44 as shown in Fig. 3B. A plate 24 (Fig. 3D) is bent or curved and then welded to peripheral U-shaped edges 39, 41 of each of the plates 38 and 42 to form the shroud. In an alternative embodiment, shown in Fig. 3E, the sheath receiving plate 42 (and also the plate at the distal end) has a continuous arcuate edge forming a portion of a circle. Various joints may be used to weld the plate 24 to the plates 38 and 42. One possibility is shown in Fig. 4, in which plate 42 has an annular lip 48 which the plate 24 slides over into abutment with the shoulder 50. The shroud 18 may be fitted to a curved surface, as for example the surface of a pipe shaped like a large helix or coil, by curving the plate 24 as shown in Figs. 5A-5C.
First, slots 52 are cut into the plate 24 at intervals. The slots are perpendicular to the shroud axis A. Second, the plate 24 is bent to close the slots 52 at their open ends.
Third, the slots 52 are welded solid.
The shroud 18 may be attached to a pipe 54 as illustrated in Figs. 6, 7 and 8, for a U-shape or tangent shape (Fig. 6) and round shape (Fig. 7). The shroud 18 is firmly secured to the pipe 54 by welding both longitudinal edges 56 of the shroud, the bottom edges 60 of the sheath adaptor 15, and the bottom edges of the plates 38 and 42 to the pipe 54. The welds are completed in conventional manner. The sheath is not welded to the pipe. Preferably, the cavity is packed with ceramic cement during manufacturing, and not at the site where the temperature sensor is to be used.
With the temperature sensing junction centered in the cavity, and with a single metal shroud packed with ceramic cement, known techniques may be used to ensure that the temperature sensing junction senses the same temperature at the measuring point as if the temperature sensor were not there. Preferably, this is carried out by finite element analysis. The factors affecting the temperature at the measuring point include the diameter and length of the cavity 30, the thermal conductivity of the materials used, the wall thickness of the shroud, the size of the weld used to secure the
5 temperature sensor to the equipment being monitored, the sheath and cable thickness, and the distance from the sheath to the temperature sensing junction. Software for making this calculation is commercially available from Algor of Pittsburgh, PA, USA.
Although a method of securing a temperature sensor to a pipe has been disclosed, the temperature sensor may also be secured to a pipe 54 by a clamp 62, formed of a metal strip 64, wrapped around the pipe 54, a bolt 66 which passes through openings in end portions of the strip 64 and nut 68, as shown in Fig.
9. The temperature sensor 10 is clamped with the open face of the cavity 30 against the pipe 54. As shown in Fig. 10, this same clamp 62 may be used to clamp a conventional temperature sensor 70 to a pipe 54. The metal strip 64 is placed perpendicularly to the main axis of the shroud 18 roughly over the center of the shroud 18 and has a width about equal to a third to one half of the length of the shroud 18, although its exact length is not critical. The edges 56 of the shroud 18 and the edges of the end plates should be flush with the surface of the pipe 54 when the temperature sensor is clamped to the pipe. In addition, the surface of the ceramic cement at the open face of the interior cavity should have a shape that conforms to the surface of the pipe, to avoid gaps between the cement and the pipe. The open face of the cavity preferably extends along the entire length of the shroud. The sheath should terminate in the cavity within about 20%, more preferably within about 10%, of the distance from the end of the shroud to the temperature sensing junction, and even more preferably is flush with the inside wall of the end plate 42.
Immaterial modifications may be made to the exemplary embodiment of the invention described here without departing from the spirit of the invention.
Although a method of securing a temperature sensor to a pipe has been disclosed, the temperature sensor may also be secured to a pipe 54 by a clamp 62, formed of a metal strip 64, wrapped around the pipe 54, a bolt 66 which passes through openings in end portions of the strip 64 and nut 68, as shown in Fig.
9. The temperature sensor 10 is clamped with the open face of the cavity 30 against the pipe 54. As shown in Fig. 10, this same clamp 62 may be used to clamp a conventional temperature sensor 70 to a pipe 54. The metal strip 64 is placed perpendicularly to the main axis of the shroud 18 roughly over the center of the shroud 18 and has a width about equal to a third to one half of the length of the shroud 18, although its exact length is not critical. The edges 56 of the shroud 18 and the edges of the end plates should be flush with the surface of the pipe 54 when the temperature sensor is clamped to the pipe. In addition, the surface of the ceramic cement at the open face of the interior cavity should have a shape that conforms to the surface of the pipe, to avoid gaps between the cement and the pipe. The open face of the cavity preferably extends along the entire length of the shroud. The sheath should terminate in the cavity within about 20%, more preferably within about 10%, of the distance from the end of the shroud to the temperature sensing junction, and even more preferably is flush with the inside wall of the end plate 42.
Immaterial modifications may be made to the exemplary embodiment of the invention described here without departing from the spirit of the invention.
Claims (27)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A temperature sensor, comprising:
a metal sheath containing sheath insulation;
a shroud having a sheath receiving end, the sheath being secured to the sheath receiving end of the shroud, the shroud forming an interior cavity open on one face, the interior cavity being filled with shroud insulation; and wires extending from the sheath into the interior cavity of the shroud and terminating at a junction, the wires being supported within the shroud by the shroud insulation, the junction being thermally insulated from the shroud and from the sheath.
a metal sheath containing sheath insulation;
a shroud having a sheath receiving end, the sheath being secured to the sheath receiving end of the shroud, the shroud forming an interior cavity open on one face, the interior cavity being filled with shroud insulation; and wires extending from the sheath into the interior cavity of the shroud and terminating at a junction, the wires being supported within the shroud by the shroud insulation, the junction being thermally insulated from the shroud and from the sheath.
2. The temperature sensor of claim 1 in which the junction is electrically insulated from the shroud and from the sheath.
3. The temperature sensor of claim 1 or 2 in which the shroud insulation is ceramic cement.
4. The temperature sensor of claim 1, 2 or 3 in which the shroud has a distal end, and the junction is equidistant from the sheath receiving end and the distal end.
5. The temperature sensor of claim 4 in which the junction is centered in the interior cavity of the shroud.
6. The temperature sensor of any one of claims 1-5 in which the junction is covered by shroud insulation, for forming an ungrounded junction.
7. The temperature sensor of any one of claims 1-5 in which the shroud insulation has a boundary at the open face of the shroud, and the junction is at the boundary of the shroud insulation, for forming a grounded junction.
8. The temperature sensor of any one of claims 1-7 in which the shroud comprises:
a first plate forming the sheath receiving end, the first plate having a first edge;
a second plate forming the distal end, the second plate having a second edge;
and a curved plate welded to each of the first and second edges of the first and second plates.
a first plate forming the sheath receiving end, the first plate having a first edge;
a second plate forming the distal end, the second plate having a second edge;
and a curved plate welded to each of the first and second edges of the first and second plates.
9. The temperature sensor of any one of claims 1-7 in which the shroud has spaced longitudinal edges extending between the sheath receiving end and the distal end, the longitudinal edges being contoured for securing to equipment to be monitored, and the interior cavity extending between the spaced longitudinal edges of the shroud.
10. The temperature sensor of any one of claims 1-9 in which the temperature sensor is clamped to a pipe by a clamp extending over the shroud, with the open face of the interior cavity against the pipe.
11. The temperature sensor of any one of claims 1-10 in which properties of the shroud and insulation are selected so that, in use, the junction senses the same temperature at the measuring point as if the temperature sensor were not there.
12. A temperature sensor, comprising:
a metal sheath containing sheath insulation;
a shroud having a sheath receiving end, the sheath being secured to the sheath receiving end of the shroud, the shroud forming an interior cavity open on one face, the interior cavity being filled with ceramic cement; and wires extending from the sheath into the interior cavity of the shroud and terminating at a junction, the wires being supported within the shroud by the ceramic cement, the junction being thermally insulated from the shroud and from the sheath.
a metal sheath containing sheath insulation;
a shroud having a sheath receiving end, the sheath being secured to the sheath receiving end of the shroud, the shroud forming an interior cavity open on one face, the interior cavity being filled with ceramic cement; and wires extending from the sheath into the interior cavity of the shroud and terminating at a junction, the wires being supported within the shroud by the ceramic cement, the junction being thermally insulated from the shroud and from the sheath.
13. The temperature sensor of claim 12 in which the junction is electrically insulated from the shroud and from the sheath.
14. The temperature sensor of claim 12 or 13 in which the temperature sensing junction is centered in the cavity.
15. The temperature sensor of claim 12, 13 or 14 in which the junction is covered by shroud insulation, for forming an ungrounded junction.
16. The temperature sensor of any one of claims 12, 13 or 14 in which the shroud insulation has a boundary at the open face of the shroud, and the junction is at the boundary of the shroud insulation, for forming a grounded junction.
17. The temperature sensor of any one of claims 12-16 in which the temperature sensor is clamped to a pipe by a clamp extending over the shroud, with the open face of the interior cavity against the pipe.
18. The temperature sensor of any one of claims 12-17 in which properties of the shroud and insulation are selected so that, in use, the junction senses the same temperature at the measuring point as if the temperature sensor were not there.
19. A method of making a temperature sensor, the method comprising the steps of:
providing a metal sheath containing sheath insulation;
forming a shroud having a sheath receiving end;
securing the sheath to the sheath receiving end of the shroud, the shroud forming an interior cavity open on one face;
filling the interior cavity with ceramic cement, with wires extending from the sheath into the interior cavity of the shroud and terminating at a junction, the wires being supported within the shroud by the ceramic cement, the junction being thermally insulated from the shroud and from the sheath.
providing a metal sheath containing sheath insulation;
forming a shroud having a sheath receiving end;
securing the sheath to the sheath receiving end of the shroud, the shroud forming an interior cavity open on one face;
filling the interior cavity with ceramic cement, with wires extending from the sheath into the interior cavity of the shroud and terminating at a junction, the wires being supported within the shroud by the ceramic cement, the junction being thermally insulated from the shroud and from the sheath.
20. The method of claim 19 in which the junction is electrically insulated from the shroud and from the sheath.
21. The method of claim 19 or 20 in which the temperature sensing junction is centered in the interior cavity.
22. The method of any one of claims 19, 20 or 21 in which the junction is covered by shroud insulation, for forming an ungrounded junction.
23. The method of any one of claims 19, 20 or 21 in which the shroud insulation has a boundary at the open face of the shroud, and the junction is at the boundary of the shroud insulation, for forming a grounded junction.
24. The method of any one of claims 19-23 further comprising securing the temperature sensor to a pipe by clamping the temperature sensor to the pipe by a clamp extending over the shroud, with the open face of the interior cavity against the pipe.
25. The method of any one of claims 19-23 in which properties of the shroud and insulation are selected so that, in use, the junction senses the same temperature at the measuring point as if the temperature sensor were not there.
26. A method of securing a temperature sensor to a pipe, comprising the steps of:
providing a temperature sensor, wherein the temperatures sensor comprises a shroud attached to a sheath, with wires from the sheath extending into a cavity in the shroud; and clamping the temperature sensor to a pipe by a clamp extending over the shroud.
providing a temperature sensor, wherein the temperatures sensor comprises a shroud attached to a sheath, with wires from the sheath extending into a cavity in the shroud; and clamping the temperature sensor to a pipe by a clamp extending over the shroud.
27. The method of claim 26 in which the cavity has an open face extending along the length of the shroud and clamping the temperature sensor to the pipe comprises clamping the open face of the cavity against the pipe.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2253887 CA2253887C (en) | 1998-11-04 | 1998-11-04 | Improved surface temperature sensor and related methods |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2253887 CA2253887C (en) | 1998-11-04 | 1998-11-04 | Improved surface temperature sensor and related methods |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2253887A1 CA2253887A1 (en) | 2000-05-04 |
| CA2253887C true CA2253887C (en) | 2008-07-29 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2253887 Expired - Lifetime CA2253887C (en) | 1998-11-04 | 1998-11-04 | Improved surface temperature sensor and related methods |
Country Status (1)
| Country | Link |
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| CA (1) | CA2253887C (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104458055B (en) * | 2014-12-02 | 2018-09-11 | 武汉理工大学 | Optical fibre raster package structure and its packaging method for surface temperature measurement |
| CN116989907B (en) * | 2023-09-25 | 2023-12-12 | 常州恒盾机械科技有限公司 | Wireless temperature measurement sensor protection structure for mining temperature measurement |
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1998
- 1998-11-04 CA CA 2253887 patent/CA2253887C/en not_active Expired - Lifetime
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| Publication number | Publication date |
|---|---|
| CA2253887A1 (en) | 2000-05-04 |
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Effective date: 20181105 |