Measuring sensor with flushing nozzle and measuring device

Abstract

The invention relates to a measuring sensor for process and automation technology, designed to detect measurement variables of a medium, comprising: a measuring tube (MR) for conducting the medium (ME), wherein the measuring tube (MR) has at least two bores (B1, B2) in the tube wall (RW); at least one sensor (SE, SE', SE'') arranged in a first bore (B1, B1', B1''), designed to detect at least one measurement signal dependent on the medium (ME) and / or to feed a signal into the medium; at least one flushing device (SV) arranged in a second bore (B2), wherein the flushing device (SV) has at least one flushing nozzle (SD1; SD2; SD3) with an orientation (A1; A2; A3) towards the at least one sensor (SE), wherein the flushing device (SV) is designed to be connected to a flushing liquid line (FL), wherein the flushing liquid line (FL) is designed to conduct a flushing liquid (F), wherein the at least one flushing nozzle (SD1; SD2; SD3) is designed to accelerate the flushing liquid (F) along the orientation (A1; A2; A3).

Description

[0001] Sensor with flushing nozzle and measuring device

[0002] The invention relates to a sensor for a measuring instrument with a rinsing nozzle for cleaning the sensors and a measuring instrument with such a sensor.

[0003] In automation technology, particularly in process automation, field devices are frequently used to acquire various measured variables. These variables can include, for example, fill level, flow rate, pressure, temperature, pH value, redox potential, conductivity, or dielectric constant of a medium in a process plant. To acquire these measured values, field devices incorporate suitable sensors or are based on appropriate measurement methods. The Endress+Hauser Group manufactures and distributes a wide variety of field device types.

[0004] In the so-called transmittive dielectric constant (DIP) measurement, a high-frequency signal is injected into a medium from a transmitting antenna and travels through it until it is received by a suitable receiving antenna and forwarded for processing. As the signal passes through the measurement path, especially with media containing high water content and over long distances, it is attenuated. This attenuation provides information about the dielectric constant of the medium (also known as the "dielectric constant" or "relative permittivity"). By measuring the dielectric constant of a medium, various parameters of the medium can be derived, such as its moisture content, solids content, composition, or any impurities.Therefore, determining the dielectric constant is of great interest for both solid media such as cement or grain, and liquid and gaseous media such as fuels, wastewater, gases, or chemicals. In principle, the dielectric constant can be determined for both stationary and flowing media. Accordingly, the measuring tube carrying a medium, as described in the invention, can also be understood as a tank, silo, basin, or section of pipeline.

[0005] In addition to inductive and capacitive measurement principles for determining the dielectric constant, high-frequency-based measurement principles can also be applied, analogous to level measurement. Besides the TDR principle (Time Domain Reflectometry), it is possible to determine the dielectric constant using transmittive high-frequency measurement. In this method, a high-frequency signal with at least one defined frequency or frequency change is coupled into a measuring section running through the medium within the container. After passing through the measuring section, an amplitude / amplitude change and / or a phase / phase shift are measured. From this, the dielectric constant value can be determined, for example, based on appropriate calibration measurements.A transmittive dielectric constant measuring device is described in more detail, for example, in the German publication DE102017130728A1.

[0006] Patent application DE102020134061 A1 describes a high-frequency-based field device with an antenna arrangement comprising a transmitting antenna and a receiving antenna, which measures the properties of a medium by measuring its dielectric constant. In the described field device, the antennas are in contact with the medium, which is guided in a measuring tube, through a protective device permeable to the high-frequency signal, and the properties of the medium are determined by processing the received signal.

[0007] When this type of field device is used in water and wastewater systems, for example in a wastewater treatment plant for purifying wastewater from the sewer system, the problem arises that solids contained in the wastewater can accumulate in the measuring device, particularly on the sensors and / or their protective devices. Such deposits impair the operation of the sensors and can consequently render measurements of the medium's properties inaccurate or even impossible.

[0008] The necessary cleaning of the measuring device, especially the sensors and / or their protective devices, usually requires extensive measures, such as the installation of special cleaning devices like flushing flanges, and can result in longer downtimes during measurement operation for cleaning the sensors of field devices.

[0009] The present invention therefore aims to provide a measuring sensor that can be used in water and wastewater systems without significant additional effort.

[0010] The invention solves the problem by means of a housing assembly according to independent claim 1.

[0011] The measuring device according to the invention for process and automation technology, configured to detect at least one measured quantity of a medium, comprises: a measuring tube for guiding the medium, wherein the measuring tube has at least two bores in the tube wall; at least one sensor arranged in a first bore, configured to detect at least one measurement signal dependent on the medium and / or to inject a signal into the medium; at least one flushing device arranged in a second bore, wherein the flushing device has at least one flushing nozzle with an orientation towards the at least one sensor, wherein the flushing device is configured to be connected to a flushing fluid line, wherein the flushing fluid line is configured to carry a flushing fluid, and wherein the at least one flushing nozzle is configured to accelerate the flushing fluid along the orientation.

[0012] In a further development of the measuring device according to the invention, the at least one sensor is arranged in at least one first cross-section orthogonal to a longitudinal direction of the measuring tube. The flushing device is arranged in a second cross-section orthogonal to a longitudinal direction of the measuring tube; the at least one first cross-section and the second cross-section are spaced apart from each other by no more than twice, in particular by one, preferably by half a diameter of the measuring tube, and in particular coincidentally.

[0013] In a further development of the measuring sensor according to the invention, the at least one first bore has a first bore axis; the second bore has a second bore axis; a central angle is given by an orthogonal projection of the at least one first bore axis onto the second cross-section with the second bore axis; the central angle is at least 45°, in particular at least 60°, preferably at least 80°. In this further development, the central angle is measured between the two orthogonal projections of the two bore axes and starting from their point of intersection.

[0014] In a further development of the measuring sensor according to the invention, the at least one flushing nozzle has at least one jet channel; the at least one jet channel has a further orientation; the further orientation is assigned to the flushing nozzle; the orientation of the at least one flushing nozzle is given by a vector sum of the further orientations assigned to the flushing nozzle.

[0015] In a further development of the measuring sensor according to the invention, the at least one beam channel has a diameter that is between 0.1 mm and 5 mm, in particular 1 mm to 1.5 mm.

[0016] In a further development of the measuring sensor according to the invention, the at least one sensor comprises a temperature sensor, wherein the temperature sensor projects into the measuring tube.

[0017] In a further development of the measuring sensor according to the invention, the at least one sensor comprises an antenna, wherein the antenna is configured to receive a measuring signal or to feed a signal into the medium, wherein the antenna is configured to be connected to the medium by means of a device penetrating the measuring signal and / or the signal.

[0018] The measuring device according to the invention for process and automation technology, configured to detect at least one measured quantity of a medium, comprising: a sensor according to the invention; a measuring and operating circuit; a container for a rinsing liquid, wherein the container is connected to the rinsing liquid line; a pressure generator, configured to pressurize the container; a pressure relief valve.

[0019] The inventive method for cleaning a measuring device for process and automation technology comprises at least the following steps: filling the rinsing liquid line with a rinsing liquid; setting a pressure on the rinsing liquid line, wherein the rinsing liquid is accelerated into the rinsing device by the pressure, wherein the rinsing liquid is accelerated through the at least one jet channel of the at least one rinsing nozzle towards the at least one sensor; wherein the rinsing liquid serves to remove deposits of the medium inside the measuring tube, in particular from the at least one sensor.

[0020] In a further development of the method according to the invention, the rinsing liquid comprises compressed air, cold water and hot water.

[0021] The cyclic method according to the invention for cleaning a measuring instrument in process and automation technology with several, in particular different, rinsing liquids, wherein the several rinsing liquids are contained in several containers, wherein the method comprises the repeated execution of a procedure for each of the rinsing liquids, wherein the procedure comprises at least the following steps: connecting the container containing the rinsing liquid to the rinsing liquid line; providing a quantity of the rinsing liquid; performing a method according to the invention for cleaning a measuring instrument with the provided quantity of the rinsing liquid.

[0022] The invention has the advantage that the flushing device can be integrated into common measuring instruments to make them suitable for use in a water / wastewater system. Furthermore, it offers the advantage that various deposits of solids present in the water / wastewater system can be removed from the sensors by means of a suitable flushing fluid at a suitable pressure. Another advantage is that the flushing nozzles and their jet channels are designed to align with the sensors of the measuring device, so that there are no moving parts that could introduce further uncertainties and / or require minimal maintenance.

[0023] The invention is explained using the following figures. It shows:

[0024] Fig. 1 shows a cross-section through one embodiment of the sensor.

[0025] Fig. 2 shows a cross-section through one embodiment of the flushing device.

[0026] Fig. 3 shows a top view of one embodiment of the flushing device.

[0027] Fig. 4 shows a cross-section through one embodiment of the sensor.

[0028] The cross-section through one embodiment of the measuring sensor shown in Fig. 1 reveals sensors SE, SE', SE" arranged in bores B1, BT, B1" in the pipe wall RW of a measuring tube MR. In this specific case, sensors SE, SE', SE" comprise two antennas for transmitting and receiving an electromagnetic signal and a temperature sensor. Also arranged in a bore B2 in the pipe wall RW of the measuring tube MR is the flushing device SV, which serves to clean the sensors SE, SE', SE" of deposits during operation. In this embodiment, the sensors SE, SE', SE" and the flushing device are arranged at substantially equal intervals around the measuring tube MW. The bores B1, BT, B1", B2 arranged in the pipe wall RW of the measuring tube MR have bore axes AB1, ABT, AB1", AB2, which are essentially aligned with a longitudinal axis passing through the center point of a cross-section of the measuring tube MR.

[0029] The cross-section through an embodiment of the flushing device SV shown in Fig. 2 depicts the flushing nozzles SD1, SD2, SD3 with orientations A1, A2, A3, which are filled with a flushing fluid F via a flushing fluid line FL. The orientations A1, A2, A3 each point from one of the flushing nozzles SD1, SD2, SD3, respectively, towards one of the sensors SE (not shown in this figure), whereby several flushing nozzles SD1, SD2, SD3 can be directed towards the same sensor. In operation, the flushing device SV serves to accelerate the flushing fluid F under pressure through the flushing nozzles SD1, SD2, SD3 onto the sensors SE, so that these sensors SD1, SD2, SD3 are cleaned of deposits.

[0030] The top view of one embodiment of the flushing device SV shown in Fig. 3 includes the two flushing nozzles SD1, SD2, each with three associated jet channels SK1, SK2, SK3, SK1", SK2", SK3" for cleaning the sensors SE, SE" arranged laterally in the measuring tube MR (not visible here). The flushing device also includes a third flushing nozzle SD3 with a single jet channel SKT, which is designed for cleaning the sensor SE' (not visible here) located opposite the flushing device SV on the measuring tube MR. For cleaning sensors SE, SE" with a relatively large surface area, flushing nozzles SD1 with multiple jet channels SK1, SK2, SK3 are suitable.

[0031] The cross-section shown in Fig. 4 through an embodiment of the measuring sensor comprises a measuring tube MR carrying a medium ME, with a diameter D and a tube wall RW. A sensor SE and a flushing device are arranged on the tube wall RW. The sensor SE is located at a first cross-section Q1 of the measuring tube MR, and the flushing device SV is located at a second cross-section Q2 of the measuring tube MR. In this embodiment, the distance along a measuring tube axis between the first cross-section Q1 and the second cross-section Q2 is less than the diameter D of the measuring tube MR. Reference numeral list MR measuring tube

[0032] ME Medium

[0033] RW pipe wall

[0034] B1, BT, B1”, B2 boreholes

[0035] SE, SE', SE" Sensor

[0036] SV flushing device SD1, SD2, SD3 flushing nozzle

[0037] A1, A2, A3 alignment

[0038] FL Flushing fluid line F Flushing fluid Q1, Q2 Cross-section

[0039] Diameter AB1, ABT, AB1", AB2 bore axis

[0040] SK1, SK2, SK3, SKT, SK1", SK2", SK3" Beam channel SKA1, SKA2, SKA3 further alignment

Claims

Patent claims 1. Sensors for process and automation technology, designed to detect at least one measured quantity of a medium, comprising: • a measuring tube (MR) for guiding the medium (ME), wherein the measuring tube (MR) has at least two bores (B1, B2) in the tube wall (RW); • at least one sensor (SE, SE', SE") arranged in a first bore (B1, BT, B1"), configured to detect at least one measurement signal dependent on the medium (ME) and / or to inject a signal into the medium; • at least one flushing device (SV) arranged in a second bore (B2), wherein the flushing device (SV) has at least one flushing nozzle (SD1; SD2; SD3) with an orientation (A1; A2; A3) towards the at least one sensor (SE), o wherein the flushing device (SV) is configured to be connected to a flushing fluid line (FL), wherein the flushing fluid line (FL) is configured to carry a flushing fluid (F), o wherein the at least one flushing nozzle (SD1; SD2; SD3) is configured to accelerate the flushing fluid (F) along the alignment (A1; A2; A3).

2. Measuring sensor according to claim 1, • wherein the at least one sensor (SE) is arranged in at least one first cross-section (Q1) orthogonal to a longitudinal direction of the measuring tube. • wherein the flushing device (SV) is arranged in a second cross-section (Q2) orthogonal to a longitudinal direction of the measuring tube; • wherein the at least one first cross-section (Q1) and the second cross-section (Q2) are spaced apart from each other by no more than twice, in particular once, preferably half a diameter (D) of the measuring tube (MR), and in particular coincide.

3. Measuring sensor according to claim 2, • wherein the at least one first bore (B1) has a first bore axis (AB1); • wherein the second bore (B2) has a second bore axis (AB2); • where a central angle is given from an orthogonal projection of the at least one first drilling axis (AS) onto the second cross-section (Q2) with the second drilling axis (AB2); • wherein the central angle is at least 45°, in particular at least 60°, preferably at least 80°.

4. Measuring sensor according to one of claims 1 to 3, • wherein the at least one spray nozzle (SD1; SD2; SD3) has at least one jet channel (SK1; SK2; SK3; SKT; SK1“; SK2“; SK3“); • wherein the at least one beam channel (SK1; SK2; SK3; SKT; SK1“; SK2“; SK3“) has a further orientation (SKA1; SKA2; SKA3); • where the further orientation (SKA1; SKA2; SKA3) is assigned to the flushing nozzle (SD1, SD2, SD3); • where the orientation (A1; A2; A3) of the at least one flushing nozzle (SD1, SD2, SD3) is given by a vector sum of the further orientations (SKA1; SKA2; SKA3) assigned to the flushing nozzle (SD1, SD2, SD3).

5. Sensor according to claim 4, • wherein the at least one beam channel (SK1; SK2; SK3; SKT; SK1“; SK2“; SK3“) has a diameter between 0.1 mm and 5 mm, in particular 1 mm to 1.5 mm; 6. Measuring sensor according to one of claims 1 to 5, • wherein the at least one sensor (SE) comprises a temperature sensor, • wherein the temperature sensor (SE) protrudes into the measuring tube (MR).

7. Measuring sensor according to one of claims 1 to 6, • wherein the at least one sensor (SE) comprises an antenna, • wherein the antenna is configured to receive a measurement signal or to inject a signal into the medium (ME), • wherein the antenna is configured to be connected to the medium (ME) by a device penetrating the measurement signal and / or the signal.

8. Measuring device for process and automation technology, designed to record at least one measured quantity of a medium, comprising: • a measuring sensor according to any one of claims 1 to 7; • a measuring and operating circuit; • a container for a rinsing fluid (F), wherein the container is connected to the rinsing fluid line (FL); • a pressure generator, set up to pressurize the container • a pressure relief valve.

9. Method for cleaning a measuring device for process and automation technology according to claim 8, comprising at least the following steps: • Filling the flushing fluid line (FL) with a flushing fluid (F); • Setting a pressure on the flushing fluid line (FL), wherein the flushing fluid (F) is accelerated by the pressure into the flushing device (SV), wherein the flushing fluid is accelerated through the at least one jet channel (SK1; SK2; SK3; SKT; SK1"; SK2"; SK3") of the at least one flushing nozzle (SD1, SD2, SD3) towards the at least one sensor (SE); • wherein the rinsing fluid (F) serves to remove deposits of the medium (ME) inside the measuring tube (MR), in particular from the at least one sensor (SE).

10. Method according to claim 9, • wherein the rinsing fluid (F) comprises compressed air, cold water, and hot water; 11. Cyclical method for cleaning a measuring instrument for process and automation technology with several, in particular different, rinsing liquids (F), wherein the several rinsing liquids (F) are contained in several containers, wherein the method comprises the repeated execution of a procedure for each of the rinsing liquids (F), wherein the procedure comprises at least the following steps: • Connecting the container holding the rinsing fluid (F) to the rinsing fluid line (FL); • Provide a quantity of the rinsing fluid (F); • Performing a method according to one of claims 8 to 10 with the provided quantity of rinsing fluid (F).

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