Temperature sensor, microwave sensor and magnetic-inductive flow meter

Abstract

The invention relates to a temperature sensor (1) for determining a temperature of a measurement material, comprising: - a more particularly metal probe body (2), said probe body (2) comprising: -- a more particularly at least partially conical measuring tip (3), which is designed to be brought into contact with the measurement material; -- a first probe receptacle (4), wherein the first probe receptacle (4) extends into a front portion (6) of the measuring tip (3); -- a second probe receptacle (5) which is located only in an end portion (7) of the probe body (2), - a first temperature probe (11) which is arranged in the first sensor receptacle (4) and is designed to determine a first measurement value, wherein in the first measurement value a contribution by a current temperature of the front portion predominates; and - a second temperature probe (12) which is arranged in the second probe receptacle (5) and is designed to determine a second measurement value, wherein in the second measurement value a contribution by a current temperature of the end portion (7) predominates. The invention further relates to a microwave sensor and to a magnetic-inductive flow meter.

Description

[0001] Temperature sensor, microwave sensor and magnetic-inductive flow meter

[0002] The invention relates to a temperature sensor for determining a temperature of a measuring substance, a microwave sensor for determining a solid content 8 of a solid in a flowable, in particular aqueous, measuring substance and a magnetic-inductive flow measuring device for determining a flow velocity-dependent measured variable of a flowable, in particular conductive, measuring substance.

[0003] Microwaves can be used to determine the physical quantities of permittivity and loss factor of a medium in a process line. These two quantities – measured either at one or across many different frequencies – can be used to draw conclusions about application-specific parameters, such as the water content in a mixture of water and other non-polar or slightly polar components, or the solid content in a liquid medium.

[0004] The established transmission-Z-reflection measurement is described in LF Chen, CK Ong, CP Neo, VV Varadan, VK Varadan - “Microwave Electronics, Measurement and Materials Characterization”, John Wiley & Sons Ltd., 2004. For this purpose, the microwave signal is coupled to the medium in a container or measuring tube at two different positions, the scattering parameters (transmission and, if applicable, reflection) between these coupling structures are measured, and the measured scattering parameters are used to calculate the physical properties of the medium.

[0005] WO 2018 / 121927 A1 teaches a measuring arrangement for analyzing the properties of a flowing medium using microwaves. In addition to the microwave antennas, the measuring arrangement comprises an electrically insulating lining layer on the inner surface of the measuring tube. This lining layer forms a dielectric waveguide through which a microwave signal can be transmitted, at least in part, from a first microwave antenna to a second microwave antenna. One application for such a measuring arrangement is the determination of solids content in the liquid medium being conveyed. WO 2021 / 099152 A1 teaches a microwave antenna having a front section in contact with the medium through which the excitation signal is emitted into the medium. Determining the solids content requires complex models that depend on the actual temperature of the medium. This requires precise temperature measurement.

[0006] Magnetic-inductive flow measuring devices are used to determine the flow velocity and volume flow of a flowing medium in a pipeline. A magnetic-inductive flow measuring device has a magnetic field generating device which generates a magnetic field perpendicular to the flow direction of the flowing medium. Individual coils are usually used for this purpose. In order to create a predominantly homogeneous magnetic field, additional pole shoes are shaped and attached in such a way that the magnetic field lines run across the entire pipe cross-section essentially perpendicular to the transverse axis or parallel to the vertical axis of the measuring tube. In addition, a magnetic-inductive flow measuring device has a measuring tube on which the magnetic field generating device is arranged. A device attached to the outer surface of the measuring tube orA pair of measuring electrodes arranged in measuring electrode openings in the measuring tube taps an electrical measuring voltage or potential difference perpendicular to the flow direction and the magnetic field. This voltage arises when a conductive medium flows in the direction of flow with a magnetic field applied. Since the tapped measuring voltage depends on the velocity of the flowing medium according to Faraday's law of induction, the flow velocity and - with the addition of a known pipe cross-section - the volume flow can be determined from the measured induced measuring voltage.

[0007] Magnetic-inductive flowmeters are widely used in process and automation technology for fluids with an electrical conductivity of approximately 5 pS / cm and above. The applicant markets corresponding flowmeters in a wide variety of designs for various applications, for example, under the name PROMAG. For special applications, in addition to volume flow, information regarding the temperature of the medium and / or the conductivity, which is highly temperature-dependent, is desired.

[0008] DE102012109308A1 discloses a level monitoring system for a magnetic-inductive flowmeter with an electrode for monitoring the level of a flowing medium in a pipe, which electrode has an integrated temperature sensor. A disadvantage of this solution is the thermal coupling of the electrode with the interior of the housing, which can lead to a falsified temperature measurement.

[0009] The invention is based on the object of providing an improved temperature determination.

[0010] The task is solved by the temperature sensor, the microwave sensor and the magnetic inductive flow meter.

[0011] The temperature sensor according to the invention for determining a temperature of a measuring substance, comprising:

[0012] - a sensor body, in particular a metallic one:

[0013] - a measuring tip, in particular one which is conical at least in sections, extending into a front section of the measuring tip;

[0014] - a second sensor receptacle of the sensor body is located, - a first temperature sensor is arranged and is designed to determine a first measured value, wherein in the first measured value a contribution from a current temperature of the front section predominates; and

[0015] - a second temperature sensor is arranged and is designed to determine a second measured value, wherein in the second measured value a contribution from a current temperature of the end section predominates.

[0016] Advantageous embodiments of the invention are the subject of the subclaims.

[0017] One embodiment provides that the temperature sensor, in particular the sensor body, further comprises:

[0018] - a sealant receptacle for receiving a sealant is positioned between the front section and the end section, wherein the second sensor receptacle extends up to a maximum of the sealant receptacle.

[0019] One embodiment provides that the first sensor receptacle and / or the second sensor receptacle are at least partially connected to a thermally conductive paste with four pins each via an electrical conductor, wherein two further pins are electrically connected to the second temperature sensor each via an electrical conductor.

[0020] One embodiment provides that the temperature sensor, in particular the sensor body, further comprises:

[0021] - a contact surface is positioned between the front section and the end section, with the second sensor receptacle extending up to the maximum contact surface.

[0022] The microwave sensor according to the invention for determining a solid content 8 of a solid in a flowable, in particular aqueous, measuring substance, comprising:

[0023] - a measuring tube for conveying the measuring medium;

[0024] - a transmitting antenna for generating a microwave signal passing through the measuring medium;

[0025] - a receiving antenna for receiving the microwave signal passing through the measured substance; - a housing predominates;

[0026] - an evaluation electronics is further configured to determine the solid content 8 as a function of the first measured value and the second measured value.

[0027] One embodiment provides that the first temperature sensor and the second temperature sensor are part of the temperature sensor according to the invention.

[0028] One embodiment provides that the evaluation electronics are designed to determine a compensated temperature of the measuring medium as a function of the first measured value and the second measured value.

[0029] The magnetic-inductive flowmeter according to the invention for determining a flow velocity-dependent measured variable of a flowable, in particular conductive, measuring medium, comprising:

[0030] - a measuring tube for conveying the measuring medium;

[0031] - a housing for determining a measuring voltage induced in the measuring medium;

[0032] - a magnetic field generating device for generating a magnetic field passing through the measuring tube;

[0033] - the temperature sensor according to the invention is arranged at least in sections in the magnetic field generating device.

[0034] One embodiment provides that the temperature sensor is designed as a measuring electrode, level monitoring electrode or reference electrode.

[0035] The invention is explained in more detail with reference to the following figures. They show:

[0036] Fig. 1 : a longitudinal section through a temperature sensor according to the invention;

[0037] Fig. 2: a perspective view of a microwave sensor according to the invention;

[0038] Fig. 3: a cross-section through a further embodiment of the microwave sensor according to the invention; and

[0039] Fig. 4: a cross-section through a magnetic-inductive flowmeter according to the invention.

[0040] Fig. 1 shows a longitudinal section through a temperature sensor 1 according to the invention for determining the temperature of a measured substance. The temperature sensor 1 comprises a sensor body 2. This can be made of metal. The sensor body 2 is preferably made of a material with good thermal conductivity, i.e., > 1 W / (mK). A suitable material would be steel, for example. The sensor body 2 shown is rotationally symmetrical, at least in some sections, i.e., in the front section.

[0041] In the illustrated embodiment, the sensor body 2 has a measuring tip 3 that is conical in sections. Alternatively, the measuring tip 3 can also take on a different shape, such as a cylindrical shape. The measuring tip 3 is designed to be brought into contact with the medium to be monitored. Especially for applications with solid particles in the medium, it is important to have a stable measuring tip 3 while still maintaining good thermal contact between the medium and the temperature sensor. For this purpose, the illustrated solution has a minimum thickness of 0.5 millimeters, in particular of at least 1 millimeter and a maximum of 10 millimeters.

[0042] The sensor body 2 has a first sensor receptacle 4, which extends into a front section 6 of the measuring tip 3. When the temperature sensor 1 is used, the front section 6 is in contact with the medium being measured and encompasses the center point of the measuring tip 3, toward which the sensor body 2 tapers.

[0043] A first temperature sensor 11 is arranged in the first sensor holder 4. The temperature sensor 11 can be a resistance thermometer (PT 100 or PT 1000) or a thermocouple. The first temperature sensor 11 is designed to determine and provide a first measured value. The first measured value is a current temperature present at the temperature sensor or a variable proportional thereto (e.g. electrical resistance). The determined current temperature is made up of several contributions. The first temperature sensor 11 is positioned such that the contribution to the first measured value from a current temperature of the front section and thus - when the temperature sensor is used - of the measuring medium in thermal contact with the front section.

[0044] Furthermore, the sensor body 2 has a second sensor receptacle 5, which is located exclusively in an end section 7 of the sensor body 2. The end section 7 does not come into contact with the measured medium and, when the temperature sensor 1 is installed on a container or pipeline, is located outside the part of the container or pipeline in which the measured medium is located. This means that the second sensor receptacle 5 is spaced from the first sensor receptacle 4 in the longitudinal direction of the sensor body 2. While the longitudinal axis of the sensor body 2 runs through the first sensor receptacle 4, the second sensor receptacle 6 is arranged offset in the radial direction to the longitudinal axis of the sensor body 2.

[0045] A second temperature sensor 12 is arranged in the second sensor receptacle 5 and configured to determine a second measured value. The second measured value is also a current temperature present at the temperature sensor or a value proportional to it (e.g., electrical resistance). This is also composed of several contributions. The contribution from the current temperature of the end section 7 predominates.

[0046] The second measured value can be used to correct the temperature of the medium determined from the first measured value. Especially when the ambient temperature at the measuring point differs from the temperature of the medium, the determined temperature value differs from the actual temperature of the medium.

[0047] If the ambient temperature and thus also the temperature to which the second temperature sensor 12 is exposed is significantly lower than the temperature of the measuring medium, the temperature value determined with the first temperature sensor 11 is also significantly lower than the actual temperature of the measuring medium.

[0048] If the ambient temperature and thus also the temperature to which the second temperature sensor 12 is exposed is significantly higher than the temperature of the measuring medium, the temperature value determined with the first temperature sensor 11 is also significantly higher than the actual temperature of the measuring medium.

[0049] This is because the first temperature sensor 11 is not completely thermally decoupled from the environment. The use of the second temperature sensor 12 thus has the advantage that the influences of the ambient temperature that lead to the erroneous measurement can be measured, and the temperature value determined with the first temperature sensor 11 can be corrected for the determined influence.

[0050] The aforementioned cases are static cases. However, the use of a second temperature sensor 12 also has an advantage in a dynamic case. If the temperature of the medium changes, this is measured by the first temperature sensor 11 in the front section. The heat capacity of the environment has not yet reached the temperature of the medium and thus slightly influences the measured value of the first temperature sensor 11. This leads to a measurement error. The second temperature sensor 12 in the end section also measures inaccurately due to the temperature change. However, this is delayed more than measurement with the first temperature sensor due to lower thermal coupling with the medium. During the temperature rise, a difference therefore arises between the measured values ​​measured by the two temperature sensors. The resulting difference can be used for correction.

[0051] The temperature sensor 1 shown or the sensor body 2 has a sealant receptacle 10 for holding a sealant 9. In the embodiment shown, the sealant 9 is a sealing ring. However, other sealants - such as a liquid sealing fluid - are also suitable. Standardized seals specifically for the intended application are suitable as the sealant 9. The sealant receptacle 10 is positioned between the front section e and the end section 7. During use, the sealant 9 comes into contact with the wall of the container or the pipe into which the temperature sensor 1 is inserted. In order to be able to detect the influence of the environment on the temperature measurement, it is important that the two temperature sensors are spaced as far apart as possible and that the second temperature sensor is spaced as far as possible from the measuring tip.In the illustrated embodiment, the second sensor receptacle 5 extends up to the sealant receptacle 10. The sealant receptacle 10 itself is designed as a groove that extends in the circumferential direction around the sensor body 2.

[0052] In order to achieve an optimal thermal coupling between the temperature sensors 11, 12 and the respective section to be monitored, the first sensor receptacle 4 and the second sensor receptacle 5 are at least partially filled with a thermally conductive paste 8, in particular a silicone paste.

[0053] The sensor body 2 is provided with a protective cap 13 that covers the interior of the sensor body 2. The protective cap 2 has four pins 14 (only two pins are shown due to the perspective). Two pins are electrically connected to the first temperature sensor 11 via an electrical conductor, and the other two pins are electrically connected to the second temperature sensor 12 via an electrical conductor. The protective cap 13 is integrally connected to the sensor body 2 in the end section 7. This can be achieved, for example, by means of a welding process. Alternatively, the connection between the protective cap 13 and the sensor body 2 can also be realized by a positive and / or non-positive connection.

[0054] The temperature sensor 1 or the sensor body 2, in the illustrated embodiment or in embodiments in which a sealant is explicitly omitted, has a contact surface 15 designed to serve as a stop. If the sensor body 2 is made of metal and the container or pipeline is also metallic, a suitable choice of the contact surface 15 (e.g., conical) can achieve a sufficient seal even without a sealant. In this case, the contact surface 15 is positioned between the front section 6 and the end section 7, and the second sensor receptacle 5 extends up to a maximum of the contact surface 15.

[0055] The illustrated embodiment of the sensor body 2 has an external thread 20 with which the temperature sensor 1 can be screwed into an opening with an internal thread. Furthermore, the sensor body has a hexagonal section, which is part of the end section 7.

[0056] The two electrical connectors, which connect the respective temperature sensors to the pins, each have a ceramic sleeve 30 which prevents them from coming into contact with the thermal paste 8.

[0057] The protective cap 13 has an electrical insulator 40 in which the four pins are arranged. A front section of the respective pins is located in a chamber formed by the protective cap 13 and the sensor body 2. An end section of the respective pins points away from the sensor body 2. The pins 14 are connected to an evaluation electronics via the end sections using electrical conductors (e.g. twisted cables), so that an electrical connection is established between the two temperature sensors 11, 12 and the evaluation electronics. The four pins 14 are potted with an electrically insulating potting compound 50. This serves to provide strain relief for the electrical conductor relative to the wires with which the two temperature sensors are contacted.

[0058] Fig. 2 shows a perspective view of a microwave sensor 100 according to the invention. The microwave sensor 100 is used to determine the solids content 8 of a solid in a flowable, particularly aqueous, medium. When the microwave sensor 100 is used, the medium is guided through a measuring tube 101 in a process line.

[0059] The illustrated microwave sensor 100 itself comprises a transmitting antenna 116 for generating a microwave signal that passes through the medium when a measured substance is present in the measuring tube 101. The transmitting antenna 116 is arranged in an opening of the measuring tube 101. A suitable transmitting antenna 116 is disclosed in patent DE 10 2020 134 320 A1, to which reference is made in its entirety.

[0060] Furthermore, the microwave sensor 100 comprises a receiving antenna 118 for receiving the microwave signal generated by the transmitting antenna 116 and, if a medium is present in the measuring tube 101, passing through the medium. A suitable receiving antenna 118 is also disclosed in patent DE 10 2020 134 320 A1, to which reference is made in its entirety.

[0061] Alternatively, the microwave sensor 100 can have only one antenna, which is a receiving antenna 118 and simultaneously a transmitting antenna 116. In this case, the microwave signal is generated by the antenna and also measured. For this purpose, the microwave signal is reflected at least once from an inner surface of the measuring tube back toward the transmitting antenna.

[0062] The electronic components for connecting the receiving antenna 118 and the transmitting antenna to the evaluation electronics 102 are usually protected from external influences by a housing (not shown).

[0063] The microwave sensor 100 also has a first temperature sensor 111, which is configured to determine a first measured value and provide it to the evaluation electronics. The first temperature sensor 111 is positioned on or in the measuring tube 101 in such a way that a thermal coupling is realized between the measuring medium and the first temperature sensor 111. As a result, the contribution resulting from the current temperature of the measuring medium predominates in the measured first measured value. According to the invention, the microwave sensor 100 has a further, second temperature sensor 112, which is configured to determine a second measured value. The second temperature sensor 112 is arranged significantly away from the measuring tube 101, so that the predominant contribution to the second measured value is caused by a current temperature in the housing.

[0064] An evaluation electronics unit 102, which can also be arranged in the housing or in an external transmitter housing, is configured to determine the solid content 8 as a function of a provided propagation time and / or absorption of the received microwave signal. In order to determine the solid content 8 as accurately as possible, the temperature dependence of the permittivity of water must be taken into account during the determination. For this purpose, the evaluation electronics unit 102 is configured according to the invention to determine the solid content 8 as a function of the first measured value and the second measured value.

[0065] The compensated temperature of the measured substance can not only be relevant for increasing the measurement accuracy of the solids content, but can also be displayed to the customer, for example. For this purpose, the evaluation electronics 102 is configured to determine a compensated temperature of the measured substance based on the first measured value and the second measured value.

[0066] Fig. 3 shows a cross-section through a further embodiment of the microwave sensor 100 according to the invention. The illustrated embodiment has the temperature sensor 1 according to the invention, which is arranged, in particular screwed, in an opening provided for this purpose in the measuring tube 101. Also arranged in a respective opening in the measuring tube 101 are a transmitting antenna 116 for generating a microwave signal passing through the measuring medium and a receiving antenna 118 for receiving the microwave signal passing through the measuring medium. The temperature sensor 1, the transmitting antenna 116 and the receiving antenna 118 are arranged in a housing 120, which is designed to protect them from external influences. If the measuring medium is guided through the measuring tube 101 and the temperature sensor 1 is in contact with the measuring medium, a contribution from a current temperature of the measuring medium predominates in the first measured value determined with the first temperature sensor.Although the temperature in the housing 120 also influences the first temperature value, this contribution is significantly smaller than that of the measured medium. The second measured value determined by the second temperature sensor 112 is dominated by the current temperature in the housing 120. Especially at high temperature differences, the temperature of the measured medium also contributes significantly, as it heats or cools the housing interior.

[0067] Fig. 4 shows a cross-section through a magnetic-inductive flowmeter 200 according to the invention. The structure and measuring principle of a magnetic-inductive flowmeter 200 are generally known. A flowable medium (or substance) having sufficiently high electrical conductivity is passed through a measuring tube 202. The measuring tube 202 comprises a support tube 203, which is typically made of steel, ceramic, plastic, or glass, or at least comprises one of the aforementioned materials. To prevent the measuring voltage induced in the medium from being dissipated via the electrically conductive support tube 203, the inner wall is lined with an insulating material, for example, a (plastic) liner 204 or ceramic tiles.

[0068] A magnetic field generating device 205 is arranged on the support tube 203 such that the magnetic field lines are oriented substantially perpendicular to a longitudinal direction defined by a measuring tube axis. The magnetic field generating device 205 typically comprises at least one saddle coil or at least one coil 213 with a coil core 214. In the embodiment shown in Fig. 4, the magnetic-inductive flowmeter 200 has two diametrically arranged coils 213, each having a coil core 214 and a pole piece. The two coil cores 214 are connected to one another, in particular magnetically, via a field feedback 222. The field feedback 222 connects the opposite sides of the coil cores 214 to one another. However, magnetic-inductive flowmeters 200 with exactly one coil 213, with exactly one coil core 214, and without a field feedback 222 are also known.Furthermore, magnetic-inductive flowmeters 200 are also known that have saddle coils in which no coil core is arranged. The coil 213 is connected to an operating circuit 207, which drives the coil 213 with an operating signal.

[0069] The operating signal can be a voltage with a time-varying profile and is characterized by operating signal parameters, with at least one of the operating signal parameters being controllable. The magnetic field generated by the magnetic field-generating device 205 is generated by a direct current of alternating polarity, clocked by an operating circuit 207. This ensures a stable zero point and makes the measurement insensitive to the influence of electrochemical interference. The two coils 213 can be connected separately to the operating circuit 207 or connected in series or parallel to each other.

[0070] When a magnetic field is applied, a flow-dependent potential distribution is created in the measuring tube 202, which can be detected, for example, in the form of an induced measuring voltage. A device for tapping the induced measuring voltage is arranged on the measuring tube 2. In the illustrated embodiment, the device for tapping the induced measuring voltage is formed by two oppositely arranged measuring electrodes 217, 218 for forming a galvanic contact with the medium, each of which is arranged in an electrode opening. However, magnetic-inductive flowmeters 200 are also known which have capacitive measuring electrodes arranged on the outer wall of the support tube 203, which do not come into contact with the medium. As a rule, the measuring electrodes 217, 218 are arranged diametrically and form an electrode axis or are intersected by a transverse axis that runs perpendicular to the magnetic field lines and the longitudinal axis of the measuring tube 202.However, devices for tapping the induced measuring voltage are also known which have more than two measuring electrodes. Based on the measured measuring voltage, the flow velocity-dependent measured variable can be determined. The flow velocity-dependent measured variable includes the flow velocity, the volume flow rate, and / or the mass flow rate of the medium. An evaluation electronics unit 207 is configured to detect the induced measuring voltage applied to the measuring electrodes 217, 218 and to determine the flow velocity-dependent measured variable as a function of the measured measuring voltage. The measuring electrodes 217, 218 shown are only shown in a simplified manner. According to the invention, the evaluation electronics unit 207 is configured to determine a corrected temperature of the measuring medium and / or a conductivity as a function of the first measured value and the second measured value.

[0071] Commercially available magnetic-inductive flowmeters have two additional electrodes in addition to the measuring electrodes 217, 218. First, a level monitoring electrode, ideally mounted at the highest point in the measuring tube 202, serves to detect partial filling of the measuring tube 202 and is configured to forward this information to the user and / or to take the level into account when determining the volume flow. Furthermore, a reference electrode 233, which is usually mounted diametrically opposite the level monitoring electrode or at the lowest point of the measuring tube cross-section, serves to set a controlled electrical potential in the medium. The reference electrode 233 is generally used to connect the flowing medium to a ground potential.

[0072] According to the invention, the magnetic-inductive flowmeter comprises a temperature sensor 1, which is arranged in a lateral opening in the outer surface of the measuring tube. In the illustrated embodiment, the temperature sensor 1 is arranged at least partially in the magnetic field-generating device 205 and additionally serves as a fill level monitoring electrode. Alternatively, the temperature sensor 1 can also be arranged offset in the flow direction from the magnetic field-generating device 205 and from the measuring plane in which the measuring electrodes 217, 218 are located. The temperature sensor 1 can alternatively be designed as a measuring electrode or a reference electrode.

Claims

PATENT CLAIMS 1. Temperature sensor (1) for determining a temperature of a measuring medium, comprising: - a sensor body (2), in particular a metallic one, which sensor body (2) comprises: - a measuring tip (3), in particular one which is conical at least in sections and which is designed to be brought into contact with the measuring substance; - a first sensor receptacle (4), wherein the first sensor receptacle (4) extends into a front section (6) of the measuring tip (3); - a second sensor receptacle (5) which is located exclusively in an end section (7) of the sensor body (2), - a first temperature sensor (11) which is arranged in the first sensor receptacle (4) and is designed to determine a first measured value, wherein in the first measured value a contribution from a current temperature of the front section predominates; and - a second temperature sensor (12) which is arranged in the second sensor receptacle (5) and is designed to determine a second measured value, wherein in the second measured value a contribution from a current temperature of the end section (7) predominates.

2. Temperature sensor (1) according to claim 1, further comprising: - a sealing means receptacle (10) for receiving a sealing means (9), in particular a sealing ring, wherein the sealing means receptacle (10) is positioned between the front section (6) and the end section (7), wherein the second sensor receptacle (5) extends up to a maximum of the sealing means receptacle (10).

3. Temperature sensor (1) according to claim 1 or 2, wherein the first sensor receptacle (4) and / or the second sensor receptacle (5) is / are at least partially filled with a thermally conductive paste (8), in particular a silicone paste and preferably a silicone rubber.

4. Temperature sensor (1) according to one of the preceding claims, further comprising: - a protective cap (13) with four pins (14), two pins being electrically connected to the first temperature sensor (11) via an electrical conductor each, two further pins being electrically connected to the second temperature sensor (12) via an electrical conductor each.

5. Temperature sensor (1) according to one of the preceding claims, further comprising: - a contact surface (15) which is designed to serve as a stop, wherein the contact surface (15) is positioned between the front section (6) and the end section (7), wherein the second sensor receptacle (5) extends up to a maximum of the contact surface (15).

6. Microwave sensor (100) for determining a solid content 8 of a solid in a flowable, in particular aqueous, measuring substance, comprising: - a measuring tube (101) for guiding the measuring medium; - a transmitting antenna (116) for generating a microwave signal passing through the measuring substance; - a receiving antenna (118) for receiving the microwave signal passing through the measuring substance; - a housing (120); - a first temperature sensor (111) which is arranged to determine a first measured value, where in the first measured value a contribution from a current temperature of the measured substance predominates; - a second temperature sensor (112) which is configured to determine a second measured value, wherein in the second measured value a contribution from a current temperature in the housing (120) predominates; - an evaluation electronics (102) which is designed to determine the solid content 8 as a function of a provided propagation time and / or absorption of the received microwave signal, wherein the evaluation electronics (102) is further designed to determine the solid content 8 as a function of the first measured value and the second measured value.

7. Microwave sensor (100) according to claim 6, wherein the first temperature sensor (11, 111) and the second temperature sensor (12, 112) are part of a temperature sensor (1) according to one of claims 1 to 7.

8. Microwave sensor (100) according to claim 6 or 7, wherein the evaluation electronics (102) is configured to determine a compensated temperature of the measuring substance as a function of the first measured value and the second measured value.

9. A magnetic-inductive flowmeter (200) for determining a flow velocity-dependent measured variable of a flowable, in particular conductive, medium, comprising: - a measuring tube (202) for guiding the measuring medium; - a housing (220); - at least two measuring electrodes (217, 218) for determining a measuring voltage induced in the measuring substance; - a magnetic field generating device (205) for generating a magnetic field passing through the measuring tube (202); - a temperature sensor (1) according to one of claims 1 to 5; - an evaluation electronics (207) which is designed to determine a corrected temperature of the measuring medium and / or a conductivity as a function of the first measured value and the second measured value.

10. The magnetic-inductive flowmeter according to claim 9, wherein the temperature sensor (1) is arranged at least partially in the magnetic field-generating device (205).

11. The magnetic-inductive flowmeter according to claim 9 or 10, wherein the temperature sensor (1) is designed as a measuring electrode, level monitoring electrode, or reference electrode.

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