MEASURING INSERT FOR SENSING TEMPERATURE

Abstract

The present disclosure relates to a measuring insert for insertion into a protective tube for determining and/or monitoring a temperature of a medium in a vessel or pipe, which protective tube at least partially protrudes into an inner volume of the vessel or pipe, the measuring insert including: an elongated tube; a temperature sensor arranged inside an end region of the measuring insert; and a coupling element connected to the elongated tube in the end region in which the temperature sensor is arranged, which coupling element is embodied and/or dimensioned so as to serve for fixing the measuring insert inside the protective tube in a state in which the measuring insert is introduced into the protective tube.

Claims

1. A measuring insert for introduction into a protective tube for determining and/or monitoring a temperature of a medium in a vessel or pipe, which protective tube is configured to at least partially protrude into an inner volume of the vessel or pipe, the measuring insert comprising: an elongated tube having a distal end region; a temperature sensor disposed within the end region of the elongated tube; and a coupling element connected to the elongated tube in the end region in which the temperature sensor is disposed, which coupling element is configured so as to fix the measuring insert inside the protective tube in a state when the measuring insert is introduced into the protective tube.

2. The measuring insert of claim 1, wherein the coupling element is at least partially composed of a thermally conductive material.

3. The measuring insert of claim 2, wherein the coupling element comprises a first component and a second component, the first component being at least partially composed of a rigid material and the second component being at least partially being composed of an elastic material.

4. The measuring insert of claim 1, wherein the coupling element comprises at least one at least partially elastic and/or deformable element.

5. The measuring insert of claim 4, wherein the at least one at least partially elastic and/or deformable element includes a metallic mesh or a metallic foam.

6. The measuring insert of claim 4, wherein the at least one at least partially elastic and/or deformable element includes a metallic spring element.

7. The measuring insert of claim 6, wherein the spring element is configured such that a spring travel of the spring element is perpendicular to a longitudinal axis of the elongated tube.

8. The measuring insert of claim 6, wherein the spring element comprises a plurality of outwardly curved bars and at least one ring-shaped connection element, to which the plurality of curved bars is connected, wherein the plurality of curved bars are evenly distributed around a circumference of the connection element.

9. The measuring insert of claim 1, wherein the coupling element comprises a filling material, wherein the filling material is a powder or a paste.

10. The measuring insert of claim 9, wherein the coupling element comprises a graphite powder.

11. The measuring insert of claim 1, wherein the coupling element is connected to the elongated tube by a force-fit and/or form-fit connection.

12. The measuring insert of claim 1, wherein the coupling element is connected to the elongated tube by a braze or a solder connection.

13. The measuring insert of claim 1, wherein the coupling element comprises a fastening means for fastening the coupling element to the measuring insert.

14. The measuring insert of claim 13, wherein the fastening means comprise a ring element having an inner diameter corresponding to an outer diameter of the elongated tube.

15. A thermometer for determining and/or monitoring a temperature of a medium in a vessel or pipe comprising: the measuring insert according to claim 1; and a protective tube configured to at least partially protrude into an inner volume of a vessel or pipe, wherein the measuring insert is disposed within the protective tube and connected thereto by the coupling element.

16. The thermometer of claim 15, further comprising electronics connected to the temperature sensor via connection lines and configured to determine and/or monitor the temperature of the medium.

17. The thermometer of claim 15, further comprising electronics in communication with the temperature sensor and configured to determine and/or monitor the temperature of the medium.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In the following, the present disclosure will be explained in greater detail based on the drawings presented, which include:

[0024] FIG. 1 shows a thermometer comprising a measuring insert and a protective tube according to the state of the art;

[0025] FIGS. 2a and 2b show embodiments of a measuring insert with a coupling element comprising an elastic and/or deformable element in the form of a foam according to the present disclosure;

[0026] FIG. 3 shows a further embodiment of a measuring insert with a coupling element comprising an elastic and/or deformable element in the form of a spring element according to the present disclosure;

[0027] FIGS. 4a-4c show several embodiments of a spring element according to the present disclosure; and

[0028] FIG. 5 shows an embodiment with a coupling element comprising a spring element and a mesh according to the present disclosure.

[0029] In the figures, identical elements are always provided with the same reference sign.

DETAILED DESCRIPTION

[0030] FIG. 1 shows a schematic diagram of a state of the art thermometer 1 for determining the temperature T of a medium M in a vessel V, the thermometer 1 comprising a protective tube 2, a measuring insert 3 and electronics 4. The measuring insert 3 is inserted into the protective tube 2 and comprises an elongated tube 3a in which temperature sensor 5, here in the form of a resistive element, is arranged. In certain embodiments, the temperature sensor, e.g., comprises a thermocouple of a resistive element. The temperature sensor 5 is electrically contacted via the connection lines 6 and connected to the electronics 4. In other embodiments, the electronics 4 can also be arranged separately from the measuring insert 3 and protective tube 2. Also, the temperature sensor 5 does not necessarily need to be a resistive element, or the number of connecting lines 6 used need not necessarily be two. Rather, a different number of connecting lines 6 can be used depending on the measuring principle applied.

[0031] To improve thermal contacting a spring element 7 is frequently arranged inside the protective tube 2 and/or a paste 8 is provided in the inner volume V of the thermowell 2. However, that way only insufficient mechanical stability and thermal contacting is achieved. Typically, air gaps between an inner wall of the thermowell 2 and an outer wall of the measuring insert 3 are not sufficiently minimized. This results in higher response times of the thermometer 1, less mechanical stability and a certain sensitivity towards vibrations.

[0032] The present disclosure addresses these problems by providing a coupling element 9. Exemplary embodiments of a measuring insert 3 comprising a coupling element 9 are shown in FIGS. 2a and 2b. The coupling element 9 is connected to the elongated tube 3a in the end region in which the temperature sensor 5 is arranged and is embodied and/or dimensioned so as to serve for fixing the measuring insert 3 inside the protective tube 2 when inserted therein. Further, that way a sensitivity of the thermometer 1 to mechanical vibrations can also be highly reduced.

[0033] In certain embodiments, the coupling element 9 is at least partially composed of a thermally conductive material, e.g., a metal. Such an embodiment results in an improved performance of the thermometer 1. In particular, a response time of the thermometer 1 in response to a change of the temperature T of the medium M is significantly reduced.

[0034] In case of the embodiment shown in FIG. 2a, the coupling element 9 comprises at least one at least partially elastic and/or deformable element in the form of, for example, a metallic, foam 10, which may be connected to the elongated tube 3a. The coupling element 9 may further comprise a filling material 11 filled into remaining gaps in the foam 10. The elastic and/or deformable element can also be, for example, a metallic, mesh.

[0035] As illustrated in FIG. 2b, the coupling element 9 may further also comprise at least two different components 12 serving different purposes, e.g., one rigid component 12a and one elastic component 12b. For example, the coupling element 9 in such that the second, elastic component 12b is provided by the elastic and/or deformable element, e.g., a foam or mesh 10, and the first component 12a, e.g., in the form of a rigid frame.

[0036] Examples for preferred materials for the coupling element 9 are stainless steel, copper, brass, aluminum or others.

[0037] Another embodiment is shown in FIG. 3. Here, the at least partially elastic and/or deformable element is a spring element 13. A spring travel a of the spring element 13 is perpendicular to a longitudinal axis 1 of the measuring insert 3. The coupling element 9 further comprises fastening means 14 with two ring elements 15 connected to the measuring insert 3, here to the elongated tube 3a, in between which the spring element 13 is arranged.

[0038] Several embodiments for the spring element 13 are shown in FIGS. 4a-4c. The spring element 13 shown in FIG. 4a comprises a plurality of outward curved bars 15 and two ring-shaped connection elements 16. The bars 15 are clamped and connected between the two connecting elements 16, and evenly distributed around the circumference of the connecting elements 16. The quantity of bars 15 as well as their dimension, e.g., length and width, can vary from one embodiment to another. For instance, in case of the spring element 13 shown in FIG. 4b, the number of bars 15 provided is less as in case of FIG. 4a, but the width of each bar 15 is larger. Moreover, while two connection elements 15 are provided for the embodiment shown in FIG. 4a, the one shown in FIG. 4b comprises one connecting element 16. Another embodiment of a spring element 13 is subject to FIG. 4c. Here, three connection elements 16 are provided, whereas bars 15 are provided in each case between two adjacent connecting elements 16.

[0039] Another embodiment is presented in FIG. 5. The coupling element 9 is arranged in the end region of the elongated tube 3a of the measuring insert 3. The coupling element 9 comprises a spring element 13 connected by the fastening means 14 in the form of two ring shaped elements 15 similar, as in the embodiment shown in FIG. 3. Moreover, a mesh 10 is provided at the tip of the elongated tube 3a. That way, the coupling element 9 comprises a mesh 10 and a spring element 13. Alternatively, a metallic foam can be provided instead of the mesh 10.