Sensor with flow switch and direction indication function

Abstract

The utility model discloses a sensor with a flow switch and a direction indication function, belongs to the technical field of gas flow and flow direction measurement, and aims to solve the problems of large flow resistance, slow reaction action and poor sensitivity of a traditional gas flow direction measurement structure. And a novel thermosensitive measurement structure has the problems of poor reliability, large error and small application range. The sensor comprises a shell, a gas through groove formed in the length extension direction of a pipeline is machined in the outer circle face of the shell, the sensor comprises a first thermosensitive probe and a second thermosensitive probe, and the first thermosensitive probe and the second thermosensitive probe are sequentially arranged in the gas through groove in the extension direction of the pipeline. And the length size of the extension section of the first thermosensitive probe in the shell is the same as the length size of the extension section of the second thermosensitive probe in the shell. The sensor principle and structure are mainly used for judging whether gas flows in a pipeline or not and judging the flowing direction in a common industrial field.

Description

Technical Field

[0001] The utility model belongs to the technical field of gas flow and direction measurement, and in particular relates to a sensor with flow switch and direction indication functions. Background Art

[0002] In industrial production, it is necessary to measure whether the gas transported by the pipeline is flowing and the flow direction in many occasions, that is, flow switch and flow direction detection. At present, there are two ways to measure the flow direction of gas, usually baffle measurement and piston measurement. The baffle measurement structure is to add a swingable windshield in the pipe body. As the gas flows through, it drives the windshield to swing, and then the swing direction of the windshield is used to determine whether there is gas flow in the pipeline. The piston measurement structure is to connect a piston structure in series in the pipeline. There is an inclined angle between the axis of the piston structure and the axis of the pipeline. When the gas flows through, it will push the piston to move along the axis, and then the flow direction information is transmitted through the action of the piston end and the relay. When the gas stops flowing, the piston will rely on the reset spring to reset. The advantages of the two are that the structure is relatively stable and not easy to damage, but the disadvantages are also very obvious. The baffle measurement structure and the piston measurement structure have large flow resistance, slow response, and poor sensitivity. In addition, the piston measurement structure has the disadvantage of only being able to measure unidirectional flow direction, and is usually used as a positive way to verify the flow direction of gas in large flow pipelines. Accuracy, therefore, based on the above-mentioned drawbacks, it is very in line with practical needs to develop a new method to replace the traditional flow direction measurement structure. Patent application number CN202220452149.3, named Gas Flow Direction Detection Device and Thermal Flow Sensor, proposes a solution for measuring gas flow direction. The technical means adopted is based on the principle of thermal conductivity. The gas is heated and the specific flow direction of the gas is determined by thermistors located on both sides of the heating component. The disadvantage of this solution is that the application document is a solution based on semiconductor chips. The component size is small and suitable for use in thin pipes. For general industrial occasions (under different environments with large temperature or pressure changes) and in pipelines with problems such as pollution, this naked semiconductor chip is not applicable, and it is basically ineffective after protection. In general industrial occasions, the detection results of microscopic devices directly measured sometimes have large errors from the actual results. Therefore, based on the existing technology, it is very in line with practical needs to develop a gas flow direction sensor with strong reliability, small measurement error and wide application range. Utility Model Content

[0003] The utility model provides a sensor with flow switch and direction indication functions in order to solve the problems of large flow resistance, slow reaction and poor sensitivity of the traditional gas flow direction measurement structure, and the problems of poor reliability, large error and small application range of the new thermal sensitive measurement structure.

[0004] A sensor with flow switch and direction indication functions, the sensor comprising a shell, the outer circumferential surface of the shell being processed with a gas through groove arranged along the extension direction of the pipeline length, the sensor comprising a first thermal probe and a second thermal probe, the first thermal probe and the second thermal probe being arranged in the gas through groove in sequence along the extension direction of the pipeline, and the top end of the first thermal probe being inserted into the inner top of the gas through groove, a gap being arranged between the other end of the first thermal probe and the inner bottom of the gas through groove, the top end of the second thermal probe being inserted into the inner top of the gas through groove, a gap being arranged between the other end of the second thermal probe and the inner bottom of the gas through groove, the first thermal probe and the second thermal probe having the same structure, and the length dimension of the extension section of the first thermal probe in the shell being the same as the length dimension of the extension section of the second thermal probe in the shell;

[0005] Furthermore, an external thread is processed on the outer circumferential surface of the top of the housing;

[0006] Furthermore, the first thermal probe and the second thermal probe are both composed of an armored tube and a thermistor, the top end of the armored tube is inserted into the inner top of the gas channel, the bottom end of the armored tube is closed, and the thermistor is installed in the armored tube;

[0007] Furthermore, the ratio of the wall thickness to the diameter of the armored tube is 1:10;

[0008] Furthermore, the diameter of the armored tube is 3 mm, and the wall thickness of the armored tube is 0.3 mm;

[0009] Furthermore, the ratio of the width of the gas-passing strip hole to the diameter of the bottom end of the shell is 1:1.1-1.25;

[0010] Furthermore, the length dimension of the extension section of the No. 1 thermal probe in the shell is 0.7 to 0.9 times the height dimension of the inner cavity of the shell:

[0011] Furthermore, the axis of the first thermal probe, the axis of the second thermal probe and the center line of each gas-passing strip hole in the width direction are arranged in the same plane;

[0012] The beneficial effects of this application compared to the prior art are as follows:

[0013] The present application proposes a thermal conductivity sensor for measuring the flow direction of gas in a pipeline, which adopts a double-needle structure set at equal lengths, and both probes are thermosensitive probes. Different from the existing thermosensitive detection structure in which thermistors passively receive heat, the passing wind needs to be heated by a central heating component first, and then the gas with heat contacts the thermistors located on both sides of the central heating component to determine the measurement method of gas flow. The measurement principle of the present application is reliable and the measurement structure is simpler. The present application adopts two thermosensitive probe structures arranged in sequence along the extension of the pipeline. This position design allows the two thermosensitive probes to shield each other in preparation for subsequent flow direction measurement. Before measurement, the two thermosensitive probes are preheated, that is, the two thermistors are powered on for heating, which can make them heated with equal voltage or equal current, so that the two probes have the same initial heat. In this way, when gas passes through the pipeline, the thermosensitive probe that first contacts the gas is directly exposed to the gas. When in contact with the gas, its temperature will drop significantly, and the thermistor that contacts the gas later will be blocked by the thermistor in front of it, so the amplitude of its temperature drop will be smaller than the former. In this way, according to the temperature of the two thermistors after the gas flows through, it is possible to judge whether there is gas flow and the direction of gas flow in the pipeline. The gas flow direction is from the low-temperature thermistor to the high-temperature thermistor. The technical solution proposed in the present application has extremely small error in actual application, and can accurately judge whether there is gas flow and the direction of gas flow in the pipeline, and has little effect on the flow resistance of the gas. The temperature range of gas flow direction detection is large, and the flow direction measurement of gas with a temperature of -30 to 850°C can be realized. At the same time, the armored tube added to the outside of the thermistor can greatly protect the thermistor without affecting the normal operation of the thermistor, so that it can be used in general working condition pipelines and contaminated pipelines, which greatly increases the scope of use of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is an axial schematic diagram of the sensor structure described in this application;

[0015] Figure 2 It is a schematic diagram of the front view of the sensor structure described in this application;

[0016] Figure 3 is a side view schematic diagram of the sensor structure described in this application;

[0017] Figure 4 is a schematic top view of the sensor structure described in this application;

[0018] Figure 5 A schematic top-sectional view of the sensor structure described in this application;

[0019] Figure 6It is a structural schematic diagram of the thermal probe in the sensor structure described in this application;

[0020] In the figure, 1 is a shell, 11 is a gas passage, 2 is a No. 1 thermistor, 3 is a No. 2 thermistor, 4 is an armored tube and 5 is a thermistor. DETAILED DESCRIPTION

[0021] Specific implementation method 1: Combination Figures 1 to 6 The present embodiment is described. In the present embodiment, a sensor with flow switch and direction indication functions is provided. The sensor comprises a housing 1. A gas through groove 11 arranged along the extension direction of the pipeline is processed on the outer circumferential surface of the housing 1. The sensor comprises a first thermal probe 2 and a second thermal probe 3. The first thermal probe 2 and the second thermal probe 3 are sequentially arranged in the gas through groove 11 along the extension direction of the pipeline, and the top end of the first thermal probe 2 is inserted into the inner top of the gas through groove 11, and a gap is provided between the other end of the first thermal probe 2 and the inner bottom of the gas through groove 11. The top end of the second thermal probe 3 is inserted into the inner top of the gas through groove 11, and a gap is provided between the other end of the second thermal probe 3 and the inner bottom of the gas through groove 11. The first thermal probe 2 and the second thermal probe 3 have the same structure, and the length dimension of the extension section of the first thermal probe 2 in the housing 1 is the same as the length dimension of the extension section of the second thermal probe 3 in the housing 1.

[0022] The ratio of the width of the gas-passing strip hole 11 to the diameter of the bottom end of the housing 1 is 1:1.1-1.25;

[0023] The length of the extension section of the No. 1 thermal probe 2 in the housing 1 is 0.7 to 0.9 times the height of the inner cavity of the housing 1;

[0024] The axis of the first thermal probe 2, the axis of the second thermal probe 3 and the center line of each gas-passing strip hole 11 in the width direction are arranged in the same plane.

[0025] In this embodiment, the thermal conductivity principle and the double needle structure with the same extension length at the front and back are utilized. By heating the thermistor in each needle, and judging the temperature difference and relative position of the thermistor, it is judged whether there is gas flowing through the pipeline and the flow direction. The ratio of the width of the gas passing through the strip hole 11 to the diameter of the bottom end of the shell 1 is 1:1.1-1.25, which can help to ensure the stability and uniformity of gas circulation, and avoid the gas passing through the strip hole 11 with a width that is too small, resulting in the gas being squeezed when passing through and affecting the measurement result. The length dimension of the extension section of the No. 1 thermal probe 2 in the shell 1 is 0.7-0.9 times the height dimension of the inner cavity of the shell 1. Such a setting can avoid a small gap between the bottom end of the thermistor and the inner bottom, and a larger contact surface with the thermistor when the gas is flowing, which is beneficial to improve the sensitivity of the thermistor when it is working.

[0026] Specific implementation method 2: Combination Figures 1 to 6 This embodiment is described. The difference between this embodiment and the first embodiment is that an external thread is processed on the outer circumferential surface of the top of the housing 1. The other components and connection methods are the same as those of the first embodiment.

[0027] In this embodiment, the external thread on the top of the shell 1 is used to connect the sensor to the thermal conductivity gas mass flowmeter or external heating component. It is worth noting that in this application, in order to facilitate the preheating of thermistor probe No. 1 2 and thermistor probe No. 2 3, the tops of thermistor probe No. 1 2 and thermistor probe No. 2 3 must extend to the outside of the shell 1, so that the arrangement is convenient for wiring.

[0028] Specific implementation method three: Combination Figures 1 to 6 This embodiment is described. The difference between this embodiment and the second embodiment is that the first thermal probe 2 and the second thermal probe 3 are both composed of an armored tube 4 and a thermistor 5. The top end of the armored tube 4 is inserted into the inner top of the gas channel 11, the bottom end of the armored tube 4 is closed, and the thermistor 5 is filled in the armored tube 4. Other components and connection methods are the same as those of the second embodiment.

[0029] In this embodiment, the thermistor 5 is protected by the armored tube 4, so that the thermistor 5 can work in an environment with large temperature and pressure changes, so that it will not be affected by the temperature difference and pressure difference. Since the thermistor 5 itself is relatively fragile, it is easy to corrode in some polluted environments, thereby destroying the structure of the thermistor itself and making it ineffective. The thermistor 5 protected by the armored tube 4 has a certain corrosion resistance and can be used in polluted pipes. The combination of the two greatly broadens the scope of use of the sensor.

[0030] Specific implementation method four: Combination Figures 1 to 6 This embodiment is described. The difference between this embodiment and the third embodiment is that the diameter of the armored tube 4 is 3 mm, and the wall thickness of the armored tube 4 is 0.3 mm. Other components and connection methods are the same as those of the third embodiment.

[0031] In the present embodiment, considering that the armored tube 4 should not affect the measurement sensitivity of the internal thermistor 5 when the sensor is in use, an armored tube structure with a wall thickness not exceeding 0.3 mm is used as the main body of the probe. At the same time, considering the protection strength of the armored tube 4 during operation, the tube diameter should not be too large when the wall thickness is constant. A large tube diameter can easily affect the structural strength of the armored tube 4 itself, which is easy to deform in a high pressure difference or high temperature difference environment. Therefore, the relationship between the wall thickness and the tube diameter tooth size is generally maintained at about 1:10, so that a good and stable probe structure can be achieved.

[0032] The present invention has been disclosed as above with preferred implementation cases, but it is not used to limit the present invention. Any technician familiar with the profession can make some changes or modifications to equivalent implementation cases with equivalent changes by using the above-disclosed structures and technical contents without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above implementation cases based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

[0033] How it works

[0034] The present application provides a thermal conductivity sensor for measuring the flow direction of gas in a pipeline. When working, the sensor is first set in the target pipeline, and it is ensured that the arrangement of the No. 1 thermal probe 2 and the No. 2 thermal probe 3 is arranged along the extension direction of the pipeline. Since the internal core parts of the No. 1 thermal probe 2 and the No. 2 thermal probe 3 are thermistors, the No. 1 thermal probe 2 and the No. 2 thermal probe 3 are heated by the electrical system to increase the temperature of both. When the gas in the pipeline flows in one direction, for example, when the gas in the pipeline flows from the No. 1 thermal probe 2 to the No. 2 thermal probe 3, the heat dissipation of the No. 1 thermal probe 2 is greater than that of the No. 2 thermal probe 3 (because the No. 1 thermal probe 2 blocks a part of the gas), so the temperature of the No. 2 thermal probe 3 is increased. The temperature of the thermal probe No. 1 is higher than that of the thermal probe No. 2, thereby determining whether there is gas flow in the pipeline, and through the relative temperature difference between the thermal probe No. 1 and the thermal probe No. 2, determining whether the airflow is flowing from the thermal probe No. 1 to the thermal probe No. 2, when the airflow flows from the thermal probe No. 2 to the thermal probe No. 1, the heat dissipation of the thermal probe No. 2 is greater than that of the thermal probe No. 1 (because the thermal probe No. 2 blocks part of the wind), so the temperature of the thermal probe No. 1 is higher than that of the thermal probe No. 2, thereby determining whether there is gas flow in the pipeline, and through the relative temperature difference between the thermal probe No. 1 and the thermal probe No. 2, determining whether the airflow is flowing from the thermal probe No. 1 to the thermal probe No. 2, 3.

Claims

1. A sensor with flow switch and direction indication functions, the sensor comprising a housing (1), the outer circumferential surface of the housing (1) being processed with a gas through groove (11) arranged along the direction of extension of the pipeline length, characterized in that: The sensor further comprises a first thermosensitive probe (2) and a second thermosensitive probe (3), the first thermosensitive probe (2) and the second thermosensitive probe (3) being arranged in sequence in the gas passage groove (11) along the extension direction of the pipeline, and the top end of the first thermosensitive probe (2) is inserted into the inner top of the gas passage groove (11), and a gap is provided between the other end of the first thermosensitive probe (2) and the inner bottom of the gas passage groove (11), the top end of the second thermosensitive probe (3) is inserted into the inner top of the gas passage groove (11), and a gap is provided between the other end of the second thermosensitive probe (3) and the inner bottom of the gas passage groove (11), the first thermosensitive probe (2) and the second thermosensitive probe (3) have the same structure, and the length dimension of the extension section of the first thermosensitive probe (2) in the housing (1) is the same as the length dimension of the extension section of the second thermosensitive probe (3) in the housing (1).

2. A sensor with flow switch and direction indication functions according to claim 1, characterized in that: An external thread is machined on the outer circumferential surface of the top of the housing (1).

3. A sensor with flow switch and direction indication functions according to claim 2, characterized in that: The first thermal probe (2) and the second thermal probe (3) are both composed of an armored tube (4) and a thermistor (5); the top end of the armored tube (4) is inserted into the inner top of the gas passage (11); the bottom end of the armored tube (4) is closed; and the thermistor (5) is installed in the armored tube (4).

4. A sensor with flow switch and direction indication functions according to claim 3, characterized in that: The ratio of the wall thickness to the tube diameter of the armored tube (4) is 1:

10.

5. A sensor with flow switch and direction indication functions according to claim 4, characterized in that: The wall thickness of the armored tube (4) is 0.3 mm, and the tube diameter of the armored tube (4) is 3 mm.

6. A sensor with flow switch and direction indication functions according to claim 5, characterized in that: The length dimension of the extension section of the No. 1 thermal probe (2) inside the housing (1) is 0.7 to 0.9 times the height dimension of the inner cavity of the housing (1).

7. A sensor with flow switch and direction indication functions according to claim 6, characterized in that: The axis of the first thermal probe (2), the axis of the second thermal probe (3) and the center line of the width direction of the gas passage (11) are arranged in the same plane.

8. A sensor with flow switch and direction indication functions according to claim 7, characterized in that: The ratio of the width dimension of the gas passage (11) to the diameter dimension of the bottom end of the outer shell (1) is 1:1.1-1.25.

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