Measuring device

Abstract

The present disclosure relates to a device for determining and/or monitoring at least one process variable of a medium including at least one sensor element and a unit at least partially including a material with anisotropic thermal conductivity. According to the present disclosure the unit is frictionally connected to the sensor element, and in particular the unit is frictionally fastened on a surface of the sensor element.

Claims

1. A device for determining and/or monitoring at least one process variable of a medium, the device comprising: a sensor element; and a unit embodied as a thin film, which at least partially comprises a material with anisotropic thermal conductivity, wherein the unit is frictionally fastened on a surface of the sensor element, and wherein the film is configured both to enable the frictional fastening of the sensor element and to enable a uniform distribution of heat as to facilitate a thermal equilibrium.

2. The device of claim 1, wherein the sensor element is a temperature sensor.

3. The device of claim 1, wherein the material with anisotropic thermal conductivity is an at least partially carbon-containing material or hexagonal boron nitride.

4. The device of claim 3, wherein the material with anisotropic thermal conductivity is graphite.

5. The device of claim 1, wherein the unit includes a hole therethrough.

6. The device of claim 1, wherein the unit includes, at least in a first sub-region in which the unit is frictionally fastened to the sensor element, a first diameter, which is smaller than a second diameter of the unit in a second sub-region.

7. The device of claim 1, further comprising a fastener configured to support the frictional fastening between the unit and the sensor element.

8. The device of claim 7, wherein the fastener comprises a screw, a rivet, a clamp or a solder.

9. The device of claim 7, wherein the fastener consists of a solder.

10. The device of claim 1, wherein the unit is embodied as a flexible, thin film, and wherein the unit is fastened to the sensor element in a first end region.

11. The device of claim 10, wherein the film is configured and arranged such that, starting from the first end region fastened to the sensor element, the film is wound around the sensor element.

12. The device of claim 11, wherein the unit is frictionally fastened in a second end region to a further component of the device.

13. The device of claim 12, wherein the further component is a sensor housing, in which the sensor element is disposed, or the further component is a carrier element, on which the sensor element is arranged.

14. The device of claim 1, wherein the unit is embodied as a flexible, thin film, and wherein the unit is fastened to the sensor element in a central region.

15. The device of claim 14, wherein the film is configured and arranged such that, starting from the central region fastened to the sensor element, the film is arranged at least partially around the sensor element on two mutually opposing sides of the sensor element.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention is explained in more detail based upon the following drawings. The following are shown:

(2) FIG. 1 shows a schematic diagram of a thermometer with a sensor element in the form of a temperature sensor according to the prior art arranged in a sensor head;

(3) FIG. 2a shows an embodiment of a device according to the present disclosure with a unit fastened in an end region on a sensor element

(4) FIG. 2b shows an embodiment of a device according to the present disclosure with a unit fastened in a central region on a sensor element;

(5) FIGS. 3a-3d show embodiments for producing a frictional connection with the aid of a solder; and

(6) FIG. 4 shows an embodiment of a device according to the present disclosure with a unit fastened to a sensor element and to a sensor housing.

DETAILED DESCRIPTION

(7) FIG. 1 shows a schematic representation of a thermometer 1 with a dipping body or a protective tube 2, a measuring insert 3, and an electronic unit 4 according to the prior art. The measuring insert 3 is introduced into the dipping body 2 and comprises a sensor element 5, which in the present case is a temperature sensor in the form of a resistance element, which is contacted electrically and is connected to an electronic unit 4 via the connecting lines 6. However, the sensor element 5 does not necessarily have to be part of a measuring insert 3. In other embodiments, the electronic unit 4 can also be arranged separately from the measuring insert 3 and dipping body 2. In addition, the sensor element 5 need not necessarily be a resistance element, nor does the number of connection lines 6 used need necessarily be two. It is rather the case that, depending on the measurement principle used, a different number of connecting wires 6 can be used.

(8) The sensor element 5 is frictionally fastened to a bottom surface B, facing the medium M, of the measuring insert 2 by means of a solder connection in an internal volume of the measuring insert 2. As already explained in the introduction, such a connection is associated with high manufacturing requirements. The quality and reproduction of the solder connection influence the thermal properties of the device 1 to a great extent.

(9) According to the present disclosure, to provide a high degree with mechanical stability with simultaneously good thermal properties, a unit 8 comprising a material with anisotropic thermal conductivity is frictionally connected to the sensor element 5, as illustrated in FIGS. 2a and 2b for two exemplary embodiments of a device according to the invention. In both embodiments, as well as for the embodiments shown below, the unit 8 is in each case produced without limiting generality in the form of a thin film of a material with anisotropic thermal conductivity, for example, graphite.

(10) For the embodiment according to FIG. 2a, the unit 8 in FIG. 2a is fastened to the sensor element 5 in an end region E1 and wound around the sensor element 5. In the embodiment shown in FIG. 2b, however, the unit 8 is fastened to the sensor element 5 in a central region MB and surrounds the sensor element 5 on two mutually opposing sides. In both cases, the unit 8 is arranged at least partially around the sensor element 5 and at least partially surrounds the sensor element 5. In this way, a rapid heat transfer from the medium M to the sensor element 5, and thus a homogeneous heat distribution within the protective tube 2, can be ensured; especially, a region of the protective tube 2 facing the medium M, the unit 8 and the sensor element 5 are in thermal equilibrium.

(11) To produce the frictional connection between the unit 8 and the sensor element 5, fastening means 10, 11 can be used, as illustrated by way of example in FIGS. 3a-3d.

(12) For the embodiments shown in FIGS. 3a-3c, the unit 8 has a hole 9, which in the present case is arranged in the end region E1 by way of example. The frictional connection can be produced through the hole. Fastening means 10, 11 can be used to produce the connection, as shown in FIG. 3b for the case of a solder 10 and in FIG. 3c for the case of a rivet. In this case, the solder 10 acts like a rivet 11. Alternatively, it is also conceivable for the unit E1 to have a smaller first diameter d1 in a first sub-region T1 than a second diameter d2 of the unit in a second sub-region T2. In this case, the fastening means 10, 11 can be designed, for example, in the form of a clamp [not shown], which is clamped around the unit 8 in the first sub-region T1. The diameters d1 and d2 can be constant in the two sub-regions T1 and T2 or can also be variable at least in sections.

(13) It is also conceivable to arrange multiple identical or different sensor elements 5, or also at least one sensor element 5 and at least one further component, for example a heating/cooling element and/or a reference element for in situ calibration of at least one sensor element 5, in different regions of the unit 8. It should also be noted that the sensor element 5 and the unit 8 do not necessarily have to be arranged in a dipping body 2. For example, it is also conceivable for the unit 8 and the at least one sensor element 5 to be arranged on a carrier element [not shown here]. In this case, it is also conceivable for the unit 8 and the at least one sensor element 5 to be frictionally connected to the unit 8 and the carrier element.

(14) One possibility for stabilization, protection and/or further thermal insulation can consist of a sheathing of the respectively used fastening means at the respective connection point. The sheathing can be, for example, an elastic coating, a potting or an adhesive.

(15) A further embodiment is shown in FIG. 4. In this embodiment, the unit 8 is also designed in the form of a thin film. It is frictionally connected in a first end region E1 to a sensor element 5 and in a second end region E2 to a bottom surface of a protective tube 2, in which the sensor element 5 is arranged. Alternatively, it can also be connected to a side wall of the protective tube 2 or to another component of the device 1.

LIST OF REFERENCE SIGNS

(16) 1 Thermometer 2 Protective tube 3 Measuring insert 4 Electronic unit 5 Sensor element 6 Connection lines 7 Solder connection according to the prior art 8 Unit with a material with anisotropic thermal conductivity 9 Hole 10 Solder 11 Rivet B Bottom surface of the protective tube d1, d2 Diameter of the unit T1, T2 Sub-regions of the unit E1, E2 End regions of the unit MB Central region of the unit M Medium T Temperature