Bar flowmeter with self-cleaning function

Abstract

The utility model discloses a bar flowmeter with a self-cleaning function, which comprises a transmitter and a pressure tapping pipe, and the pressure tapping pipe extends from one side of a medium pipeline; the pressure tapping pipe is of a three-cavity structure, the section of the pressure tapping pipe is in a bullet shape, the first cavity is located in the head and provided with a first pressure tapping opening facing the air incoming direction, the third cavity is located in the tail, the two sides of the third cavity are provided with second pressure tapping openings, and the second cavities are located in the middle. A first one-way check valve is arranged between the bottom of the first cavity and the bottom of the second cavity; a second one-way check valve is arranged between the bottom of the second cavity and the bottom of the third cavity; the gas inlet end of the second cavity is connected with a high-pressure gas source through a purging pipe, and a first valve is arranged between the gas inlet end and the high-pressure gas source; the first cavity and the third cavity are connected with a transmitter through pipelines. The device can be used for blowing the pressure tapping pipe in the forward and reverse directions, and has the characteristics of high accuracy, safety and reliability.

Description

Technical Field

[0001] The utility model relates to the technical field of flow meter purging, in particular to a bar-type flow meter with a self-cleaning function. Background Art

[0002] Bar flow meters are widely used in the metallurgical industry to measure the flow of medium gases such as air, blast furnace and converter gas. Take the blast furnace and converter gas produced during steel smelting as an example. Since these gases contain moisture, dust and have a high temperature, when the gas passes through the pressure tapping port on the pressure tapping pipe, the dust and other particles and moisture in the gas will accumulate. As the use time increases, the pressure tapping hole will gradually become blocked, resulting in distortion of the flow meter measurement results. Changes in process gas pressure and gas on and off will further aggravate the blockage. The existing purging design mainly purges from the open end of the pressure taking tube to the bottom of the pressure taking tube. During the purging process, the purging gas flows out from the pressure taking port and takes away the blockage. However, there are problems: first, sometimes the blockage is directly blown into the bottom of the tube, gradually accumulates at the bottom of the tube, and slowly causes some pressure taking ports to be completely blocked. Moreover, purging from a single direction is not conducive to the complete separation of adhesions. Second, purging is generally performed regularly or at a subjective human judgment. If the pressure in the pipeline changes frequently and significantly, it will cause frequent gas exchange in the pressure taking tube, which may also aggravate the blockage. This factor is not taken into account during purging. Utility Model Content

[0003] The utility model is used to overcome the defects of the prior art and provide a bar flow meter with a self-cleaning function to solve the problems mentioned in the background art.

[0004] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0005] A bar flow meter with a self-cleaning function comprises: a transmitter and a pressure-taking tube, wherein the pressure-taking tube is inserted from one side of a medium pipeline; the pressure-taking tube is a three-cavity structure, and its cross section is in the shape of a bullet, wherein the first cavity is located at the head, and a first pressure-taking port facing the incoming gas direction is opened on it, the third cavity is located at the tail, and second pressure-taking ports are opened on both sides thereof, and the second cavity is located in the middle; a first one-way check valve is arranged between the bottom of the first cavity and the bottom of the second cavity; a second one-way check valve is arranged between the bottom of the second cavity and the bottom of the third cavity; the air inlet end of the second cavity is connected to a high-pressure gas source through a purge pipe, and a first valve is arranged between the two; the first cavity and the third cavity are connected to the transmitter through a pipeline.

[0006] In the above-mentioned bar flow meter with self-cleaning function, the first cavity, high-pressure gas source and transmitter are connected to the three interfaces of the first three-way valve through pipelines respectively; the third cavity, high-pressure gas source and transmitter are connected to the three interfaces of the second three-way valve through pipelines respectively.

[0007] The above-mentioned bar flow meter with self-cleaning function is additionally provided with a CPU and a control circuit, and a pressure sensor P is arranged on the medium pipeline. The output signal of the pressure sensor P is connected to the input end of the CPU, and the output end of the CPU is respectively connected to control the first valve, the first three-way valve, and the second three-way valve.

[0008] For the above-mentioned bar flow meter with self-cleaning function, the number of the first pressure ports is 5-7, and the number of the second pressure ports is 10-14.

[0009] The above-mentioned bar flow meter with self-cleaning function, the high-pressure gas source is high-pressure nitrogen. Beneficial Effects

[0010] Compared with the existing laser analyzer, the utility model has the following advantages: First, a pressure-taking tube with a three-cavity structure is provided, and the second cavity is located in the middle of the pressure-taking tube, and its bottom is respectively connected to the first cavity and the third cavity through a one-way check valve. By connecting a high-pressure gas source to the second cavity, the first cavity and the third cavity can be purged from the bottom in the reverse direction, which helps to completely remove the impurities accumulated in the pressure-taking tube. Second, by providing a three-way valve between the first cavity, the transmitter, and the high-pressure gas source, the connection between the first cavity and the transmitter can be achieved during pressure taking, and the connection between the high-pressure gas source and the first cavity can also be achieved during forward purging; similarly, the pressure taking and forward purging of the third cavity adopt the same structural design. By reversely purging and forward purging the first cavity and the third cavity, the blockage can be completely removed, ensuring the accuracy of the measurement. Fourth, when the medium gas pressure is stable, air flow impurities are not easy to enter the pressure taking tube. However, when the air pressure fluctuates greatly, the gas in the pressure taking tube will frequently exchange with the medium pipeline gas, making it easy for impurities to enter. Therefore, a pressure sensor P is set to monitor the pressure changes of the medium gas. When the pressure fluctuates frequently, the CPU controls the forward and reverse purge of the pressure taking tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The utility model is further described in detail below in conjunction with the accompanying drawings.

[0012] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0013] Figure 2 It is a cross-sectional view of the pressure taking pipe of the utility model;

[0014] Figure 3 It is a schematic diagram of the local structure of the pressure taking pipe of the utility model;

[0015] The symbols in the figure represent:

[0016] 1. Transmitter, 2. Pressure taking pipe, 3. Medium pipeline, 4. First one-way check valve, 5. Second one-way check valve, 6. Purge pipe, 7. High-pressure gas source, 8. First three-way valve, 9. Second three-way valve, 10. First valve. DETAILED DESCRIPTION

[0017] The utility model is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0018] like Figure 1-3 As shown, the utility model comprises a transmitter 1 and a pressure pipe 2, wherein the pressure pipe 2 is inserted into the medium pipe 3 from one side of the medium pipe 3. The transmitter is a differential pressure transmitter or a transmitter integrating differential pressure and temperature, which is a prior art of flow meter.

[0019] In order to achieve a thorough purge of the pressure-taking pipe during maintenance without affecting the pressure taking during operation, the following scheme is adopted: the pressure-taking pipe 2 is a three-cavity structure, and its cross-section is in the shape of a bullet. The first cavity 2-1 is located at the head, that is, the head of the bullet shape in cross section, and a first pressure-taking port 2-1-1 facing the incoming gas direction is opened on it, and the third cavity 2-3 is located at the tail, and second pressure-taking ports 2-3-1 are opened on both sides thereof, and the second cavity 2-2 is located in the middle; a first one-way check valve 4 is arranged between the bottom of the first cavity 2-1 and the bottom of the second cavity 2-2; a second one-way check valve 5 is arranged between the bottom of the second cavity 2-2 and the bottom of the third cavity 2-3; the air inlet end of the second cavity 2-2 is connected to the high-pressure gas source 7 through a purge pipe 6, and a first valve 10 is arranged between the two; the first cavity 2-1 and the third cavity 2-3 are connected to the transmitter 1 through a pipeline. The number of the first pressure ports is 5 to 7, and the number of the second pressure ports is 10 to 14. The high-pressure gas source 7 is high-pressure nitrogen.

[0020] The above design ensures that the purge gas in the second cavity can only flow into the first cavity and the third cavity from the bottom in one direction, while the medium gas in the first cavity and the third cavity cannot flow into the second cavity. The first one-way check valve 4 and the second one-way check valve 5 can be arranged on the end cover, and then the end cover is connected to the bottom of the pressure taking tube 2 to respectively realize the indirect connection between the second cavity, the first cavity and the third cavity; the two check valves can also be connected to the three cavities through pipelines. By connecting a high-pressure gas source to the second cavity, the first cavity and the third cavity can be purged in the reverse direction from the bottom, which helps to completely remove impurities accumulated in the pressure taking tube.

[0021] The above is the reverse purge from the bottom of the pressure-taking tube, and forward purge can also be added: the first cavity 2-1, the high-pressure gas source 7 and the transmitter 1 are respectively connected to the three interfaces of the first three-way valve 8 through pipelines; the third cavity 2-3, the high-pressure gas source 7 and the transmitter 1 are respectively connected to the three interfaces of the second three-way valve 9 through pipelines. In the working state, when measuring the pressure difference, the first cavity and the third cavity are respectively connected to the transmitter, and when forward purge is required, the first cavity and the third cavity are respectively connected to the high-pressure gas source.

[0022] When the medium gas pressure is stable, the airflow impurities are not easy to enter the pressure-taking tube. However, when the air pressure fluctuates greatly, the gas in the pressure-taking tube will frequently exchange with the medium pipeline gas, so that impurities can easily enter. Therefore, by setting a pressure sensor P to monitor the pressure change of the medium gas, when the pressure fluctuates frequently, the CPU controls the forward and reverse purge of the pressure-taking tube. The scheme is as follows: add a CPU and a control circuit, set a pressure sensor P on the medium pipeline 3, the output signal of the pressure sensor P is connected to the input end of the CPU, and the output end of the CPU is connected to control the first valve 10, the first three-way valve 8, and the second three-way valve 9 respectively. The first valve 10, the first three-way valve 8, and the second three-way valve 9 can be solenoid valves or other power valves. The CPU can first use the C8051F340 series chip, whose input and output can fully meet the needs. The output of the CPU can be connected to the control relay through the triode amplifier circuit, and then connected to control each valve through the relay. The CPU can purge the pressure-taking tube regularly, and can also purge the pressure-taking tube according to the fluctuation of the medium gas pressure.

Claims

1. A bar flow meter with self-cleaning function, comprising: A transmitter (1), a pressure-taking tube (2), the pressure-taking tube (2) being inserted from one side of a medium pipeline (3); characterized in that the pressure-taking tube (2) is a three-cavity structure, and its cross section is in the shape of a bullet head, the first cavity (2-1) is located at the head, and a first pressure-taking port (2-1-1) facing the incoming gas direction is opened on it, the third cavity (2-3) is located at the tail, and second pressure-taking ports (2-3-1) are opened on both sides of the third cavity (2-3), The second cavity (2-2) is located in the middle; a first one-way check valve (4) is arranged between the bottom of the first cavity (2-1) and the bottom of the second cavity (2-2); a second one-way check valve (5) is arranged between the bottom of the second cavity (2-2) and the bottom of the third cavity (2-3); the air inlet end of the second cavity (2-2) is connected to a high-pressure air source (7) via a purge pipe (6), and a first valve (10) is arranged between the two; the first cavity (2-1) and the third cavity (2-3) are connected to a transmitter (1) via a pipeline.

2. The bar flow meter with self-cleaning function according to claim 1, characterized in that: The first cavity (2-1), the high-pressure gas source (7) and the transmitter (1) are respectively connected to the three interfaces of the first three-way valve (8) through pipelines; the third cavity (2-3), the high-pressure gas source (7) and the transmitter (1) are respectively connected to the three interfaces of the second three-way valve (9) through pipelines.

3. The bar flow meter with self-cleaning function according to claim 1, characterized in that: A CPU and a control circuit are added, and a pressure sensor P is arranged on the medium pipeline (3). The output signal of the pressure sensor P is connected to the input end of the CPU, and the output end of the CPU is respectively connected to control the first valve (10), the first three-way valve (8), and the second three-way valve (9).

4. The bar flow meter with self-cleaning function according to claim 1, characterized in that: The number of the first pressure taking ports is 5-7, and the number of the second pressure taking ports is 10-14.

5. The bar flow meter with self-cleaning function according to claim 1, characterized in that: The high-pressure gas source (7) is high-pressure nitrogen.

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