SENSOR ARRANGEMENT WITH HEAT INSULATION

Abstract

A sensor arrangement which is configured for measuring a filling level, a limit level and/or a pressure and has an antenna for transmitting and/or receiving a measurement signal, a waveguide with a first waveguide section for connection to the antenna and a second waveguide section, configured for transmitting the measurement signal, and a heat insulating element. The heat insulating element is arranged between the first and second waveguide sections and is arranged to at least partially prevent heat conduction between the first and second waveguide sections. The invention further relates to a heat insulating element for a sensor arrangement, the use of a heat insulating element for heat insulation of electronics of a level, limit level and/or pressure measuring device and the use of a sensor arrangement in a process plant.

Claims

1. A sensor arrangement configured to measure a filling level, a limit level, and/or a pressure, comprising: an antenna configured to transmit and/or receive a measurement signal; a waveguide having a first waveguide section for connection to the antenna and a second waveguide section and configured to transmit the measurement signal; and a heat insulator arranged between the first waveguide section and the second waveguide section and configured to at least partially prevent heat conduction between the first waveguide section and the second waveguide section.

2. The sensor arrangement according to claim 1, wherein the antenna is a horn antenna or a parabolic antenna.

3. The sensor arrangement according to claim 1, wherein the heat insulator is tubular in shape.

4. The sensor arrangement according to claim 1, wherein the heat insulator has an inner wall which is at least partially metallized.

5. The sensor arrangement according to claim 1, wherein the heat insulator consists of a heat-insulating material.

6. The sensor arrangement according to claim 5, where the heat-insulating material is a plastic or ceramic.

7. The sensor arrangement according to claim 6, wherein the plastic is polyether ether ketone (PEEK), or wherein the ceramic is a silicate ceramic or a zirconium oxide ceramic.

8. The sensor arrangement according to claim 1, wherein the heat insulator includes a first insulator configured to receive the first waveguide section and a second insulator configured to receive the second waveguide section and is configured to allow a temperature of the sensor arrangement to drop along a length of the heat insulator between the first insulator and the second insulator.

9. The sensor arrangement according to claim 4, wherein the heat insulator is further configured to transmit the measurement signal within the heat insulator with the inner wall between the first waveguide section and the second waveguide section of the waveguide.

10. The sensor arrangement according to claim 1, wherein the heat insulator further comprises a connecter configured to secure the heat insulator to the first waveguide section and/or the second waveguide section.

11. The sensor arrangement according to claim 10, wherein the connecter is a spring connection or a snap connection.

12. The sensor arrangement according to claim 8, wherein an inner wall of the heat insulator corresponds to an inner wall of the waveguide when the first waveguide section is connected to the first insulator and/or when the second waveguide section is connected to the second insulator.

13. The sensor arrangement according to claim 1, further comprising: measurement electronics with a radar chip connected to the second waveguide section of the waveguide and configured to generate a measurement signal and/or to evaluate a measurement signal from the antenna.

14. A heat insulator for a sensor having an antenna and a waveguide, the heat insulator comprising: a first insulator configured to receive a first waveguide section of the waveguide; and a second insulator configured to receive a second waveguide section of the waveguide, wherein the heat insulator is arranged to at least partially prevent heat conduction between the first waveguide section and the second waveguide section.

15. The sensor arrangement according to claim 2, wherein the heat insulator is tubular in shape.

16. The sensor arrangement according to claim 2, wherein the heat insulator has an inner wall which is at least partially metallized.

17. The sensor arrangement according to claim 3, wherein the heat insulator has an inner wall which is at least partially metallized.

18. The sensor arrangement according to claim 2, wherein the heat insulator consists of a heat-insulating material.

19. The sensor arrangement according to claim 3, wherein the heat insulator consists of a heat-insulating material.

20. The sensor arrangement according to claim 4, wherein the heat insulator consists of a heat-insulating material.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0053] FIG. 1 shows a sensor arrangement according to an embodiment.

DETAILED DESCRIPTION OF EMBODIMENTS

[0054] FIG. 1 shows a sensor arrangement 100 which is configured to measure a filling level, a limit level and/or a pressure and has an antenna 110, a waveguide 120, a heat insulating element 130 and an electronic measuring system 150 with a radar chip.

[0055] The antenna 100 can be a horn antenna or a parabolic antenna and can be configured to transmit and/or receive a measurement signal.

[0056] The waveguide 120 can have a first waveguide section 121, which can be configured for connection to the antenna 110, and a second waveguide section 122, which can be configured for connection to the measurement electronics 150 or a high-frequency electronics unit. The waveguide 120 can be configured to transmit the measurement signal from the measurement electronics 150 in the direction of the antenna 110 or vice versa.

[0057] For example, the waveguide 120 can be made of a metal, such as copper or stainless steel.

[0058] The heat insulating element 130 is arranged between the first waveguide section 121 and the second waveguide section 122 and may be arranged to at least partially prevent heat conduction between the first waveguide section 121 and the second waveguide section 122.

[0059] The heat-insulating element 130 can be made of a heat-insulating material, which can be a plastic or a ceramic. For example, the heat-insulating material of the heat-insulating element 130 may be a plastic PEEK or a ceramic such as a silicate ceramic or a zirconium oxide (ZrO) ceramic.

[0060] It may be necessary for the thermally insulating material to have a lower thermal conductivity than the metallic waveguide 120. For example, the copper waveguide 120 may have a conductivity of 401 W/(m.Math.K) or a stainless steel waveguide 120 may have a conductivity of 15 W/(m.Math.K). The high-temperature-resistant thermoplastic PEEK as the heat-insulating material has a conductivity of 0.25 W/(m.Math.K) and can be provided to prevent the heat transport of the sensor arrangement 100 with a waveguide 120 made of copper or the stainless steel. A zirconia (ZrO) ceramic with a thermal conductivity of 2 W/(m.Math.K) may also be suitable for the copper or stainless steel waveguide. In contrast, an aluminum oxide (Al O.sub.23) ceramic with a thermal conductivity of 30 W/(m.Math.K) can be a suitable thermal insulating material for the copper waveguide, but not for the stainless steel waveguide.

[0061] The heat insulating element 130 can be tubular in shape. For example, the heat insulating element 130 can have a recess or a bore in order to form a round or rectangular feedthrough in the heat insulating element 130. For example, the hole for an RF radar chip with an operating frequency of 80 GHz may have a diameter of 2.6 mm.

[0062] In addition, the heat insulating element 130 can have an inner wall, which can be at least partially metallized. Alternatively, the heat insulating element 130 can also be completely metallized. Preferably, the metallization can be applied only in the tenth or hundredth range, such as with a coating thickness of 0.1 to 0.001 mm, whereby the thermal conductivity of the heat insulating element 130 after metallization can also be low. In this way, heat conduction or heat transport in the direction of the measurement electronics 150 can be effectively prevented and the radar signal can be routed without interference and continuously at the same time.

[0063] The thermal insulating member 130 may include a first insulating member portion 131 having a first passageway at a first end of the thermal insulating member 130 and a second insulating member portion 132 having a second passageway at an opposite second end of the thermal insulating member 130, wherein the first insulating member portion 131 may be adapted to receive the first waveguide section 121 and the second insulating member portion 132 may be adapted to receive the second waveguide section 122.

[0064] The heat insulating element 130 is configured to allow a temperature of the sensor arrangement to be lowered along the length of the heat insulating element 130 between the first insulating element section 131 and the second insulating element section 132. For example, the radar chip, which can be an RF radar chip, and the measurement electronics can only be subjected to a temperature of up to 85? C. If a process temperature reaches a high temperature of 130? C. or higher, the provision of the thermal insulation element 130 can advantageously enable the sensor arrangement 100 to be built compactly during use, so that the temperature of the sensor arrangement 100 can be reduced from the high process temperature to a temperature below 85? C. in a short design with the aid of the thermal insulation element.

[0065] The first passage of the first insulating element section 131 may have a larger diameter than the bore of the thermal insulating element 130, while the second passage of the second insulating element section 132 may have a larger diameter than the bore of the thermal insulating element 130. A first abutment surface can be provided between the first passage of the first insulating element section 131 and the inner wall of the heat insulating element 130, against which the first waveguide section 121 can abut, wherein the first abutment surface can, for example, correspond to the end face of the first waveguide section 121. The first stop surface can be perpendicular to the inner wall. A second abutment surface can be provided between the second passage of the second insulating element section 132 and the inner wall of the heat insulating element 130, against which the second waveguide section 122 can abut, wherein the second abutment surface can, for example, correspond to the end face of the second waveguide section 122. The second abutment surface may be perpendicular to the inner wall. The first passage and the second passage may have the same diameter, as shown in FIG. 1, or different diameters, depending on whether the first waveguide section 121 and the second waveguide section 122 may have the same outer circumference or different outer circumferences.

[0066] The heat insulating element 130 may further comprise a connecting element, which may be arranged to fasten the heat insulating element 130 to the first waveguide section 121 and/or the second waveguide section 122. The connecting element can, for example, be a spring connection or a snap connection.

[0067] For example, by means of the connecting element, the waveguide with the first and second waveguide sections and the thermal insulation element can be pressed together by a spring-on-block connection system, so that no gap can occur between the waveguide 120 and the thermal insulation element 130.

[0068] Furthermore, the heat insulating element 130 can be set up to transmit the measurement signal within the heat insulating element 130 with the inner wall between the first waveguide section 121 and the second waveguide section 122 of the waveguide. Because the inner wall of the heat insulating element 130 can be metallized, the measurement signal or the measurement beam can be guided from the measurement electronics or the radar chip of the measurement electronics to the antenna 110 or vice versa via the first waveguide section 121, the heat insulating element 130 and the second waveguide section 122.

[0069] The inner wall of the heat insulating element 130 can correspond to the inner wall of the waveguide 120 when the first waveguide section 121 is connected to the first insulating element section and/or when the second waveguide section 122 is connected to the second insulating element section 132. Thus, the transition between the inner wall of the heat insulating element 130 and the inner wall of the waveguide 120 or the first waveguide section 121 and/or the second waveguide section can be formed without a gap, so that the measurement signal or the radar signal can be transmitted continuously within the sensor arrangement 100 without influence.

[0070] Furthermore, the heat insulating element 130 may be integrated into the waveguide 120 and form a waveguide arrangement with the waveguide 120 or the first and second waveguide sections 121, 122, which may comprise two materials, namely a plastic or a ceramic as a heat insulating material and a metal for the waveguide 120 and the metallization of the inner wall of the heat insulating element 130.

[0071] Furthermore, the antenna 110 may be integral or integrated with the waveguide 120 or the first waveguide section 121.

[0072] In addition, it should be noted that comprising and having do not exclude other elements or steps and the indefinite articles a or an do not exclude a plurality. It should also be noted that features or steps described with reference to one of the above embodiments may also be used in combination with other features or steps of other embodiments described above. Reference signs in the claims are not to be regarded as limitations.