NON-INVASIVE THERMOMETER

Abstract

An apparatus for determining and/or monitoring a process variable, for example, temperature, flow or flow velocity, of a medium in a containment includes a temperature sensor for registering temperature securable to an outer surface of the wall of the containment, at least one connection line for electrical contacting of the temperature sensor, and securement means for a releasable securing of the temperature sensor and a temperature sensor-near section of the connection line to the outer surface of the wall of the containment. According to the present disclosure, at least the section of the connection line is securable to the outer surface of the wall of the containment such that the section extends parallel with the wall of the and is in thermal contact with the wall of the containment.

Claims

1-11. (canceled)

12. An apparatus for determining and/or monitoring a process variable of a medium in a containment, the apparatus comprising: a temperature sensor configured to register a temperature, which temperature sensor is adapted to be securable to an outer surface of a wall of the containment; at least one connection line configured to electrically contact the temperature sensor; and a securement device configured to releasably secure the temperature sensor and a section of the at least one connection line at and near the temperature sensor to the outer surface of the wall of the containment, wherein at least the section of the at least one connection line is securable to the outer surface of the wall such that the section extends along the wall and is in thermal contact with the wall of the containment.

13. The apparatus of claim 12, wherein the temperature sensor is a resistance element or thermocouple.

14. The apparatus of claim 12, further comprising a reference element configured to enable in situ calibration and/or validation of at least the temperature sensor and to be securable to the outer surface of the wall of the containment, wherein the reference element comprises at least one material that has at least one phase change at at least one predetermined phase change temperature in a temperature range relevant for calibrating the temperature sensor, wherein the at least one material remains in the solid state at the at least one predetermined phase change temperature.

15. The apparatus of claim 12, further comprising a heating element configured to be securable to the outer surface of the wall of the containment.

16. The apparatus of claim 12, wherein the temperature sensor includes a temperature-sensitive sensor element, which is electrically contacted via a first connection line and a second connection line of the at least one connection line, wherein the first connection line is divided into first and second sections, wherein the first section, which is at or near the sensor element, comprises a first material, and wherein the second section, which is opposite the sensor element, comprises a second material, which differs from the first material, wherein the second connection line comprises the second material, and wherein the first section of the first connection line and at least one portion of the second connection line define a first difference temperature sensor in the form of a thermocouple.

17. The apparatus of claim 12, further comprising a heat conductive coupling unit configured to be disposed on the outer surface of the wall of the containment.

18. The apparatus of claim 17, wherein the coupling unit comprises, at least partially, a material with anisotropic thermal conductivity.

19. The apparatus of claim 18, wherein the material with anisotropic thermal conductivity is, at least partially, graphite or hexagonal boron nitride.

20. The apparatus of claim 17, wherein the coupling unit is configured and arranged as to surround at least the temperature sensor, a portion of the section of the at least one connection line and/or a portion of the containment.

21. The apparatus of claim 17, wherein the coupling unit is configured to ensure that at least the temperature sensor and the section of the at least one connection line are substantially in thermal equilibrium with the wall of the containment at all times.

22. The apparatus of claim 17, wherein the coupling unit is an elongated element having a small thickness relative to a surface area of the elongated element, thus is, for example, an elongated, thin walled foil, or an elongated layer arrangement of at least two foils.

23. The apparatus of claim 22, wherein the coupling unit is an elongated, thin-walled foil or an elongated layer arrangement of at least two foils.

24. The apparatus of claim 12, further comprising a housing configured to be externally securable to the wall of the containment and configured as to surround at least the temperature sensor and the section of the at least one connection line when the housing is secured to the wall.

Description

[0035] The invention will now be explained in greater detail based on the appended drawing, the figures of which show as follows:

[0036] FIG. 1 a thermometer for non-invasive temperature measurement according to the state of the art; and

[0037] FIG. 2 by way of example, embodiments for a thermometer of the invention.

[0038] In the figures, equal elements are provided with equal reference characters. The embodiments of the different figures are, furthermore, combinable with one another to the extent desired.

[0039] Without intending to limit the general applicability of the invention, the following description concerns thermometers. The various considerations can be directly transferred to other types of field devices, such as thermal, flow measuring devices.

[0040] Shown in FIG. 1 is a schematic view of a thermometer 1 according to the state of the art. Thermometer 1 includes a measuring insert 3 and an electronics 4. Thermometer 1 serves for registering the temperature T of a medium M, which is located in a containment 2, in such case, in the form of a pipeline. For such purpose, thermometer 1 does not protrude into the pipeline 2, but, instead, is superimposed externally on a wall W of the pipeline 2 for non-invasive temperature determination.

[0041] Measuring insert 3 includes a temperature sensor 5, which in the present case comprises a temperature sensitive element in the form of a resistance element. Temperature sensor 5 is electrically contacted and connected with the electronics 4 via the connection lines 6a, 6b.

[0042] While the shown thermometer 1 is embodied in compact construction with integrated electronics 4, in the case of other thermometers 1, the electronics 4 can also be arranged separately from the measuring insert 3. Also, temperature sensor 5 is not necessarily a resistance element and the number of connection lines 6 is not necessarily two. Rather, the number of connection lines 6 can be suitably selected, depending on applied measuring principle and applied temperature sensor 5.

[0043] As already shown, the accuracy of measurement such a thermometer 1 depends highly on the materials utilized for the thermometer and on the contacts, especially thermal contacts, especially in the region of the temperature sensor 5. Temperature sensor 5 is indirectly in thermal contact with the medium M, i.e., via the measuring insert 3 and via the wall W of the containment 2. A large role in this connection is also played by heat drain from the medium M to the environment, which can lead to an undesired temperature gradient in the region of the temperature sensor 5.

[0044] In order suitably to confront these problems according to the invention, alternative preferred embodiments for a non-invasive thermometer 1 are provided, such as shown by way of example in FIG. 2.

[0045] A first embodiment of a thermometer 1 of the invention is shown in FIG. 2a. Thermometer 1 includes a temperature sensor 5, which is electrically contacted via two connection lines 6a and 6b. Temperature sensor 5 is arranged on an outer surface of the wall W of the containment 2, and the connection lines 6a and 6b extend in the section a along the pipeline 2 and are oriented parallel with the pipeline 2. While the connection lines 6a, 6b for the shown embodiment extend in straight lines, in other embodiments they can be arranged, for example, also extending at least partially, or wound one or more times, around the containment 2. Also in such case, the course of the connection lines 6a,6b is fitted to the contour of the containment 2.

[0046] It is to be noted here that an apparatus 1 of the invention can also be applied in connection with containers and other types of containments 2. Also, the invention is not limited to embodiments with two connection lines 6a,6b. Rather, depending on type of temperature sensor 5 and depending on applied measuring principle, different numbers of connection lines 6a, 6b can be required.

[0047] Besides the temperature sensor 5, the apparatus 1 can include other components, such as, for example, a heating element 9, a reference element 10 and/or an additional temperature sensor 11. These components are, however, not shown in FIG. 2. Also, an electronics 4 is not shown in FIG. 2, solely for reasons of perspicuity.

[0048] Temperature sensor 5 and at least the section of one of the connection lines 6a,6b can, however, also be part of a measuring insert 3, such as shown in FIG. 2b. There can in other embodiments, however, also be a plurality of temperature sensors 5, or supplementally applied heating elements, cooling elements, or reference elements, arranged in the same measuring insert.

[0049] In both cases, the apparatus 1 includes, furthermore, securement means 7 for securing the temperature sensor 5 and the temperature sensor near section of one of the connection lines 6a,6b to the wall W of the containment 2. This securement means 7 is embodied in the form of tube clamps for the shown embodiments. It is noted, however, that also all other suitable securement means 7 known in the state of the art can be used and likewise fall within the scope of the invention.

[0050] In the case of the embodiment shown in FIG. 2c, the apparatus includes 1, furthermore, a heat conductive coupling unit 8, which is here embodied, by way of example, in the form of a thin walled foil. Coupling unit 8 is arranged around the wall W of the containment 2 and secured by means of the securement means 7 against the wall W of the containment 2. In such case, the coupling unit 8 surrounds the temperature sensor 5 and the section of one of the connection lines 6a,6b.

[0051] Coupling unit 8 extends preferably at least along the region of the at least one temperature sensor 5 and the section of one of the connection lines 6a,6b. It serves to lessen, or to prevent, an undesired heat drain from the process, thus, from the medium M, into the environment. It especially lessens a temperature gradient in the region of the temperature sensor 5 and the section of one of the connection lines 6a,6b.

[0052] Other embodiments can, furthermore, include a housing 11 (not shown). Housing 11 is likewise securable externally to the wall W of the containment 2 and surrounds the temperature sensor 5, the section of one of the connection lines 6a,6b, and, in given cases, the coupling unit 8.

LIST OF REFERENCE CHARACTERS

[0053] 1 apparatus

[0054] 2 containment

[0055] 3 measuring insert

[0056] 4 electronics

[0057] 5 temperature sensor

[0058] 6 connection wires

[0059] 7 securement means

[0060] 8 coupling unit

[0061] 9 heating element

[0062] 10 reference element

[0063] 11 housing

[0064] M medium

[0065] T temperature

[0066] W wall of the containment

[0067] a section of the connection lines