Anti-blocking high-precision V-cone flowmeter with two-stage throttling element

Abstract

The utility model discloses an anti-blocking high-precision V-cone flowmeter with a two-stage throttling element. The anti-blocking high-precision V-cone flowmeter at least comprises a measuring cylinder, a flow equalizing plate, a V-cone body, a high-pressure pressure guide pipe, an upstream pressure buffer pipe, a low-pressure pressure guide pipe, a downstream pressure buffer pipe, a differential pressure transmitter and a cylinder wall heater. The flow equalizing plate and the V-shaped cone are arranged in the measuring cylinder, and the flow equalizing plate is positioned at the upstream of the V-shaped cone; one end of the high-pressure pressure guide pipe is communicated with the measuring cylinder between the flow equalizing plate and the V-shaped cone through an upstream pressure buffer pipe, and the other end of the high-pressure pressure guide pipe is connected with a high-pressure interface of the differential pressure transmitter; one end of the low-pressure pressure guide pipe is communicated with the measuring cylinder body at the downstream of the V cone through a downstream pressure buffer pipe, and the other end is connected with a low-pressure interface of the differential pressure transmitter; the cylinder wall heater is arranged on the periphery of the measuring cylinder, and the high-pressure pressure guiding pipe and the low-pressure pressure guiding pipe are each provided with a wall-attached type heating pipe section attached to the cylinder wall heater. According to the device, the measurement precision and stability of small flow are improved; the blockage caused by condensation is prevented, and the stability is enhanced.

Description

Technical Field

[0001] The utility model relates to an anti-blocking high-precision V-cone flowmeter with a two-stage throttling element, which belongs to the technical field of flow measurement and is particularly suitable for accurate flow measurement in use environments such as gas media with condensable components or small and micro flows. Background Art

[0002] Flow is an important parameter for industrial production processes and scientific experiments. Flowmeter is a tool for measuring and testing flow. Gas flow measurement is an important part of the measurement field and plays a very important role in ensuring production safety, product quality, energy conservation and carbon reduction.

[0003] Gas flow measurement is very dependent on application conditions, and the influencing factors include gas type, composition, flow conditions, and field application conditions. In the laboratory, flow meters can achieve extremely high accuracy. However, in field applications, once the gas conditions or environmental conditions change significantly, the flow meter not only cannot guarantee accuracy, but may even fail to work properly. For example, when measuring small flow rates, the flow meter is not sensitive enough and the measurement deviation is large; and when the gas medium contains components that are prone to condensation or crystallization, such as water vapor, ammonia and carbon dioxide mixtures, conventional flow meters are prone to measurement pipeline blockage or water ingress into the sensing element, resulting in a large deviation between the measured value and the actual value.

[0004] Common gas flow meters can be classified according to their principles, and can be roughly divided into differential pressure flow meters, thermal flow meters, turbine flow meters, vortex flow meters, ultrasonic flow meters, etc. Among them, differential pressure flow meters are the most widely used, and there are many specific structural types.

[0005] V-cone flowmeter is a common type of differential pressure flowmeter. It uses the static pressure difference generated when the fluid flows through the V-cone as a primary measurement signal, which is connected by a pressure lead pipe, converted into an electrical signal by a differential pressure transmitter, and then converted into a corresponding flow value display through configuration.

[0006] Differential pressure flowmeters, including V-cone gas flowmeters, must connect the measured primary differential pressure signal to the differential pressure gauge via a pressure lead pipe. When some components of the measured gas are condensed or crystallized, it is easy to cause blockage in the pressure lead pipe, which in turn causes the flowmeter to be unable to operate normally. When measuring small flow rates, the flowmeter is not sensitive enough and the measurement deviation is large. Utility Model Content

[0007] In order to overcome the problems of low flow velocity, uneven flow field and large measurement deviation faced by gas flow measurement, as well as possible condensation and crystallization of some components in the measured gas when cooled, resulting in blockage, large measurement deviation and even failure to measure normally, the present invention provides an anti-blocking high-precision V-cone flowmeter with a two-stage throttling element.

[0008] In order to solve the above technical problems, the technical solutions adopted by the present utility model are as follows:

[0009] A high-precision anti-blocking V-cone flowmeter with a two-stage throttling element, comprising at least a measuring cylinder, a flow balancing plate, a V-cone, a high-pressure lead-in pipe, an upstream pressure buffer pipe, a low-pressure lead-in pipe, a downstream pressure buffer pipe, a differential pressure transmitter and a cylinder wall heater;

[0010] The flow averaging plate and the V-cone are arranged in the measuring cylinder, and the flow averaging plate is located upstream of the V-cone; the top of the V-cone faces the inlet end of the measuring cylinder, and the bottom of the V-cone faces the outlet end of the measuring cylinder.

[0011] One end of the high-pressure lead pipe is connected to the measuring cylinder between the flow equalizing plate and the V-cone through the upstream pressure buffer pipe, and the other end is connected to the high-pressure interface of the differential pressure transmitter; one end of the low-pressure lead pipe is connected to the measuring cylinder downstream of the V-cone through the downstream pressure buffer pipe, and the other end is connected to the low-pressure interface of the differential pressure transmitter;

[0012] The cylinder wall heater is arranged on the periphery of the measuring cylinder, and both the high-pressure lead-in pipe and the low-pressure lead-in pipe are provided with a wall-attached heating pipe section attached to the cylinder wall heater.

[0013] The direction from upstream to downstream in this application is consistent with the direction of gas flow. The direction from the inlet end to the outlet end of the measuring cylinder is also the direction from upstream to downstream.

[0014] The above-mentioned V-cone flowmeter uses both a V-cone and a flow equalizing plate as a throttling device. While ensuring that the ring mouth is not blocked by impurities, the V-cone is combined to improve the measurement accuracy and stability of small flow rates. The setting of the upstream pressure buffer tube and the downstream pressure buffer tube can effectively buffer shocks and pulsations, reduce fluctuations, improve the stability of the measurement readings, and enhance the stability and maintainability of the flowmeter. The design of the cylinder wall heater and the wall-mounted heating pipe section can heat the high and low pressure pressure pipes at the same time as heating the measuring cylinder, avoiding condensation of the gas medium in the pipe and ensuring the stability and accuracy of the measurement.

[0015] The measuring cylinder is a flow channel for the medium. The top of the V cone is also the tip of the V cone.

[0016] In order to ensure the accuracy of measurement and facilitate inspection and maintenance, one end of the upstream pressure buffer tube is vertically connected to the measuring cylinder between the flow equalizing plate and the V-cone, and the other end is provided with a removable inspection plug, and the end of the high-pressure pressure pipe is connected to the side wall of the upstream pressure buffer tube; one end of the downstream pressure buffer tube is vertically connected to the measuring cylinder downstream of the V-cone, and the other end is provided with a removable inspection plug, and the end of the low-pressure pressure pipe is connected to the side wall of the downstream pressure buffer tube; both the upstream pressure buffer tube and the downstream pressure buffer tube are provided with wall-attached heating pipe sections that are attached to the cylinder wall heater.

[0017] The other end of the pressure buffer tube is provided with a maintenance plug, which can be easily disassembled for maintenance, so as to check whether there is blockage in the pressure-leading tube at any time. When condensation or crystallization is found in the pressure buffer tube, the maintenance plug can be opened for inspection and cleaning.

[0018] In order to reduce the impact of pressure fluctuations on measurement accuracy during the measurement process, the diameters of the upstream pressure buffer tube and the downstream pressure buffer tube are more than 1.5 times larger than the diameters of the high-pressure lead pipe and the low-pressure lead pipe. That is, the pressure buffer tube is composed of a larger diameter pipe. When the measured medium is impacted or pulsated, the larger internal chamber can slow down the impact or pulsation and alleviate the impact on the differential pressure transmitter, thereby improving the stability and accuracy of the measurement.

[0019] In order to further enhance the maintainability of the flow monitoring device, the above-mentioned anti-blocking high-precision V-cone flowmeter with a two-stage throttling element also includes a three-valve group and a backwash control component, which plays the role of isolation and backwash cleaning; the high-pressure pressure supply pipe and the low-pressure pressure supply pipe are first connected to the three-valve group respectively, and then connected to the backwash control component respectively, and finally connected to the high and low pressure interfaces of the differential pressure transmitter respectively.

[0020] The three-valve group setting can facilitate the zero point correction and daily maintenance of the transmitter.

[0021] In order to ensure the rapid switching of the flow meter between the measurement and back-blowing states, the back-blowing control component realizes the switching between the measurement and back-blowing states through a three-way solenoid valve, and the back-blowing gas source is preferably clean air.

[0022] As a specific implementation scheme, the backblowing control component includes a first backblowing pipe, a second backblowing pipe, a first three-way solenoid valve and a second three-way solenoid valve; the first and second three-way solenoid valves are respectively arranged on the high-pressure pressure pipe and the low-pressure pressure pipe between the three-valve group and the differential pressure transmitter; one end of the first and second backblowing pipes are respectively connected to the first and second three-way solenoid valves, and the other ends are respectively connected to the backblowing gas source.

[0023] The back-blowing gas is divided into two routes. One route passes through the first back-blowing pipeline, the first three-way solenoid valve, the three-valve group, the high-pressure pressure pipe and the upstream pressure buffer pipe in sequence, and finally enters the measuring cylinder; the other route passes through the second back-blowing pipeline, the second three-way solenoid valve, the three-valve group, the low-pressure pressure pipe and the downstream pressure buffer pipe in sequence, and finally enters the measuring cylinder.

[0024] In order to facilitate installation, the inlet and outlet of the measuring cylinder are equipped with mounting flanges, which can realize standardized manufacturing and facilitate on-site installation and application.

[0025] In order to facilitate installation, disassembly, cleaning and replacement, the flow equalizing plate is preferably arranged at the inlet end face of the measuring cylinder.

[0026] The centers of the V-cone and the equalizing plate are located on the central axis of the measuring cylinder. In order to improve the accuracy of small flow measurement and reduce the disturbance effect of the upstream throttling device, the V-cone is arranged near the outlet end of the measuring cylinder, and the distance between the tip of the V-cone and the equalizing plate is preferably at least twice the inner diameter of the measuring cylinder.

[0027] In order to ensure that the ring opening of the V-cone 4 is not blocked by impurities and improve the measurement stability, a ring opening is formed between the periphery of the V-cone and the inner wall of the measuring cylinder, and circular holes are evenly distributed on the flow equalizing plate, that is, the flow equalizing plate is a porous plate structure, and the diameter of the circular hole is not greater than the minimum width of the ring opening. The minimum width of the ring opening is the interval between the bottom of the V-cone and the inner wall of the measuring cylinder.

[0028] In order to improve the heating efficiency and facilitate independent installation and maintenance, the wall-attached heating pipe sections on the high-pressure and low-pressure lead-pressure pipes are respectively coiled at both ends of the measuring cylinder, and the two do not interfere with each other; the length of the wall-attached heating pipe sections on the high-pressure and low-pressure lead-pressure pipes is at least 1 meter.

[0029] In order to prevent the high-pressure and low-pressure lead pipes from condensing and crystallizing due to the temperature drop, the non-wall-attached heating pipe sections of the high-pressure and low-pressure lead pipes are covered with an insulation layer. This can not only insulate the inside, but also ensure that the outside temperature is too high, thereby improving safety.

[0030] In order to facilitate disassembly and installation, the cylinder wall heater is a cylinder structure spliced ​​in two halves, and the cylinder wall heater is installed on the outer wall of the measuring cylinder; the cylinder wall heater is a cast aluminum heater.

[0031] The cylindrical structure of two halves spliced ​​together, that is, the cylindrical wall heater is a cylindrical structure formed by splicing two half cylinders.

[0032] The above-mentioned anti-blocking high-precision V-cone flowmeter with two-stage throttling elements is particularly suitable for measuring small flow rates and gases containing condensable components.

[0033] The technologies not mentioned in this utility model are all referred to the prior art.

[0034] The utility model discloses an anti-clogging high-precision V-cone flowmeter with a two-stage throttling element, which adopts a V-cone and a flow equalizing plate as throttling parts, and improves the measurement accuracy and measurement stability of small flow rates while ensuring that the ring mouth is not blocked by impurities; the measuring gas is buffered by the pressure buffer tube and then enters the pressure lead tube, which can effectively buffer the impact and pulsation of the airflow, reduce fluctuations, improve the stability of the measurement indication, and enhance the stability and maintainability of the flowmeter; the flowmeter also has a heating function, and when measuring a medium with a condensable component, it can prevent or reduce the problem of clogging caused by condensation of the measuring medium in the high and low pressure pressure lead tubes, and is particularly suitable for the flow measurement environment of the gas medium containing condensable components, and has the technical advantages of high sensitivity, high accuracy, wide range ratio, small throttling loss, and prevention of clogging; further, it also has backblowing control function, which enhances the maintainability of the flow monitoring device and extends the service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is the front view of the utility model anti-blocking high-precision V-cone flowmeter with two-stage throttling elements;

[0036] Figure 2 for Figure 1 Side view of

[0037] Figure 3 for Figure 1 Stereoscopic diagram.

[0038] In the figure: 1 is the measuring cylinder, 2 is the mounting flange, 3 is the flow equalizing plate, 4 is the V-cone, 5 is the cylinder wall heater, 6 is the high-pressure pressure pipe, 7 is the low-pressure pressure pipe, 8 is the upstream pressure buffer pipe, 9 is the downstream pressure buffer pipe, 10 is the maintenance plug, 11 is the differential pressure transmitter, 12 is the three-valve group, 13 is the backwash control component, 14 is the backwash pipeline, and 15 is the medium flow direction. DETAILED DESCRIPTION

[0039] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with embodiments, but the content of the present invention is not limited to the following embodiments.

[0040] In this application, directional words such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc. are based on the orientation or position relationship shown in the drawings or in use, and are only for the convenience of describing the application, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the application.

[0041] Example 1

[0042] like Figure 1-3 As shown, a high-precision anti-blocking V-cone flowmeter with a two-stage throttling element at least includes a measuring cylinder, a flow balancing plate, a V-cone, a high-pressure lead pipe, an upstream pressure buffer pipe, a low-pressure lead pipe, a downstream pressure buffer pipe, a differential pressure transmitter and a cylinder wall heater;

[0043] The flow balancing plate and the V-cone are arranged in the measuring cylinder, and the flow balancing plate is located upstream of the V-cone; the top of the V-cone faces the inlet end of the measuring cylinder, and the bottom of the V-cone faces the outlet end of the measuring cylinder.

[0044] One end of the high-pressure lead pipe is connected to the measuring cylinder between the flow equalizing plate and the V-cone through the upstream pressure buffer pipe, and the other end is connected to the high-pressure interface of the differential pressure transmitter; one end of the low-pressure lead pipe is connected to the measuring cylinder downstream of the V-cone through the downstream pressure buffer pipe, and the other end is connected to the low-pressure interface of the differential pressure transmitter;

[0045] The cylinder wall heater is arranged on the periphery of the measuring cylinder, and both the high-pressure lead-in pipe and the low-pressure lead-in pipe are provided with a wall-attached heating pipe section attached to the cylinder wall heater.

[0046] The above-mentioned V-cone flowmeter uses both a V-cone and a flow equalizing plate as a throttling device. While ensuring that the ring mouth is not blocked by impurities, the V-cone is combined to improve the measurement accuracy and stability of small flow rates. The setting of the upstream pressure buffer tube and the downstream pressure buffer tube can effectively buffer shocks and pulsations, reduce fluctuations, improve the stability of the measurement readings, and enhance the stability and maintainability of the flowmeter. The design of the cylinder wall heater and the wall-mounted heating pipe section can heat the high and low pressure pressure pipes at the same time as heating the measuring cylinder, avoiding condensation of the gas medium in the pipe and ensuring the stability and accuracy of the measurement.

[0047] Example 2

[0048] On the basis of Example 1, the following improvements were made: Figure 1 and Figure 3As shown, in order to ensure the accuracy of measurement and facilitate inspection and maintenance, one end of the upstream pressure buffer tube is vertically connected to the measuring cylinder between the flow equalizing plate and the V-cone, and the other end is provided with a detachable inspection plug, and the end of the high-pressure lead-pressure tube is connected to the side wall of the upstream pressure buffer tube; one end of the downstream pressure buffer tube is vertically connected to the measuring cylinder downstream of the V-cone, and the other end is provided with a detachable inspection plug, and the end of the low-pressure lead-pressure tube is connected to the side wall of the downstream pressure buffer tube; the upstream pressure buffer tube and the downstream pressure buffer tube are both provided with a wall-attached heating pipe section attached to the cylinder wall heater. The above-mentioned inspection plug is provided at the other end of the pressure buffer tube, which can be easily disassembled for inspection and maintenance, and it is convenient to check whether there is blockage in the lead-pressure tube at any time. When condensation and crystallization are found in the pressure buffer tube, the inspection plug can be opened for inspection and cleaning. In order to reduce the impact of pressure fluctuations on measurement accuracy during the measurement process, the diameters of the upstream pressure buffer tube and the downstream pressure buffer tube are more than 1.5 times larger than the diameters of the high-pressure lead pipe and the low-pressure lead pipe. In this example, the diameters of the upstream pressure buffer tube and the downstream pressure buffer tube are both 0.8 cm, and the diameters of the high-pressure lead pipe and the low-pressure lead pipe are both 1.5 cm. Of course, other sizes can also be selected in different usage scenarios. That is, the pressure buffer tube is composed of a larger diameter pipe. When the measured medium is impacted or pulsated, the larger internal chamber can slow down the impact or pulsation, and alleviate the impact on the differential pressure transmitter, thereby improving the stability and accuracy of the measurement.

[0049] Example 3

[0050] On the basis of Example 2, the following improvements were made: Figure 1 and Figure 3As shown, in order to further enhance the maintainability of the flow monitoring device, the anti-blocking high-precision V-cone flowmeter with a two-stage throttling element also includes a three-valve group and a backwash control component, which plays the role of isolation and backwash cleaning; the high-pressure lead pipe and the low-pressure lead pipe are first connected to the three-valve group, then connected to the backwash control component, and finally connected to the high and low pressure interfaces of the differential pressure transmitter. The setting of the three-valve group can facilitate the zero point correction and daily maintenance of the transmitter. In order to ensure the rapid switching of the flowmeter between the measurement and backwash states, the backwash control component realizes the switching of the measurement and backwash states through a three-way solenoid valve, and the backwash gas source is clean air. In this example, the backwash control component includes a first backwash pipe, a second backwash pipe, a first three-way solenoid valve and a second three-way solenoid valve; the first and second three-way solenoid valves are respectively arranged on the high-pressure lead pipe and the low-pressure lead pipe between the three-valve group and the differential pressure transmitter; one end of the first and second backwash pipes are respectively connected to the first and second three-way solenoid valves, and the other end is respectively connected to the backwash gas source. The back-blowing gas is divided into two routes. One route passes through the first back-blowing pipeline, the first three-way solenoid valve, the three-valve group, the high-pressure pressure pipe and the upstream pressure buffer pipe in sequence, and finally enters the measuring cylinder; the other route passes through the second back-blowing pipeline, the second three-way solenoid valve, the three-valve group, the low-pressure pressure pipe and the downstream pressure buffer pipe in sequence, and finally enters the measuring cylinder.

[0051] Example 4

[0052] On the basis of Example 3, the following improvements were made: Figure 1 and Figure 3 As shown, for easy installation, the inlet and outlet of the measuring cylinder are provided with mounting flanges. Standardized manufacturing can be achieved, which is convenient for on-site installation and application. In order to facilitate installation, disassembly, cleaning and replacement, the flow equalizing plate is arranged at the inlet end face of the measuring cylinder. The centers of the V-cone and the flow equalizing plate are both located on the central axis of the measuring cylinder. In order to improve the measurement accuracy of small flow rates and reduce the disturbance effect of the upstream throttling device, the V-cone 4 is arranged at a position close to the outlet end of the measuring cylinder, and the length from the tip of the V-cone 4 to the flow equalizing plate is at least greater than twice the inner diameter of the measuring cylinder. In this example, the length from the tip of the V-cone 4 to the flow equalizing plate is about 6 times the inner diameter of the measuring cylinder.

[0053] Example 5

[0054] On the basis of Example 6, the following improvements were further made: Figure 1 and Figure 3As shown, in order to ensure that the ring mouth of the V-cone 4 is not blocked by impurities and improve the measurement stability, a ring mouth is formed between the periphery of the V-cone and the inner wall of the measuring cylinder, and circular holes are evenly distributed on the flow equalizing plate, that is, the flow equalizing plate is a porous plate structure, and the diameter of the circular hole is not greater than the minimum width of the ring mouth. In order to improve the heating efficiency and facilitate independent installation and maintenance, the wall-attached heating pipe sections on the high-pressure lead-in and low-pressure lead-in pipes are respectively coiled at both ends of the measuring cylinder, and the two do not interfere with each other; the length of the wall-attached heating pipe sections on the high-pressure lead-in and low-pressure lead-in pipes is at least 1 meter. In this example, the length of the wall-attached heating pipe sections on the pressure lead-in and low-pressure lead-in pipes is 1.2 meters. Of course, other sizes can also be selected in different usage scenarios. In order to prevent the high-flow lead-in and low-pressure lead-in pipes from condensing and crystallizing the gas medium due to the decrease in temperature, the non-wall-attached heating pipe sections of the high-pressure lead-in and low-pressure lead-in pipes are coated with an insulation layer. In this way, while the inner side is insulated, it can also ensure that the outer temperature is too high, thereby improving safety. In order to facilitate disassembly and installation, the cylinder wall heater is a cylinder structure spliced ​​in two halves, and the cylinder wall heater is installed on the outer wall of the measuring cylinder; the cylinder wall heater is a cast aluminum heater.

[0055] The anti-blocking high-precision V-cone flowmeter with two-stage throttling elements in the above examples adopts a high-precision V-cone and a flow equalizing plate as a throttling component. The flow equalizing plate is a porous plate structure with multiple small circular holes evenly distributed, which can ensure that the ring mouth is not blocked by impurities. Combined with the V-cone, it can improve the measurement accuracy and stability of small flow rates. The flowmeter also has heating function and backwash control function. When measuring media with condensable components, it can prevent the measured medium from condensing in the high and low pressure lead pipes to cause blockage. It is especially suitable for the flow measurement environment of gas media containing condensable components. It has technical advantages such as high sensitivity, high accuracy, wide range ratio, small throttling loss, and anti-blockage.

Claims

1. An anti-blocking high-precision V-cone flowmeter with a two-stage throttling element, characterized in that: The device at least comprises a measuring cylinder (1), a flow balancing plate (3), a V-cone (4), a high-pressure pressure-inducing pipe (6), an upstream pressure buffer pipe (8), a low-pressure pressure-inducing pipe (7), a downstream pressure buffer pipe (9), a differential pressure transmitter (11) and a cylinder wall heater (5); The flow averaging plate (3) and the V-cone (4) are arranged in the measuring cylinder (1), and the flow averaging plate (3) is located upstream of the V-cone (4); the top of the V-cone (4) faces the inlet end of the measuring cylinder (1), and the bottom of the V-cone faces the outlet end of the measuring cylinder (1). One end of the high-pressure lead pipe (6) is connected to the measuring cylinder (1) between the flow equalizing plate (3) and the V-cone (4) through the upstream pressure buffer pipe (8), and the other end is connected to the high-pressure interface of the differential pressure transmitter (11); one end of the low-pressure lead pipe (7) is connected to the measuring cylinder (1) downstream of the V-cone (4) through the downstream pressure buffer pipe (9), and the other end is connected to the low-pressure interface of the differential pressure transmitter (11); The cylinder wall heater (5) is arranged on the periphery of the measuring cylinder (1), and the high-pressure lead-in pipe (6) and the low-pressure lead-in pipe (7) are both provided with a wall-attached heating pipe section attached to the cylinder wall heater (5).

2. The anti-blocking high-precision V-cone flowmeter with two-stage throttling element according to claim 1 is characterized in that: One end of the upstream pressure buffer tube (8) is vertically connected to the measuring cylinder (1) between the flow equalizing plate (3) and the V-cone (4), and the other end is provided with a detachable maintenance plug (10). The end of the high-pressure lead-in tube (6) is connected to the side wall of the upstream pressure buffer tube (8); one end of the downstream pressure buffer tube (9) is vertically connected to the measuring cylinder (1) downstream of the V-cone (4), and the other end is provided with a detachable maintenance plug (10). The end of the low-pressure lead-in tube (7) is connected to the side wall of the downstream pressure buffer tube (9); both the upstream pressure buffer tube (8) and the downstream pressure buffer tube (9) are provided with a wall-attached heating tube section attached to the cylinder wall heater (5).

3. The anti-blocking high-precision V-cone flowmeter with a two-stage throttling element according to claim 1 or 2, characterized in that: The diameters of the upstream pressure buffer tube (8) and the downstream pressure buffer tube (9) are respectively more than 1.5 times larger than the diameters of the high-pressure pressure-inducing tube (6) and the low-pressure pressure-inducing tube (7).

4. The anti-blocking high-precision V-cone flowmeter with a two-stage throttling element according to claim 1 or 2, characterized in that: It also includes a three-valve group (12) and a back-blowing control component (13); the high-pressure lead-in pipe (6) and the low-pressure lead-in pipe (7) are first connected to the three-valve group (12), then connected to the back-blowing control component (13), and finally connected to the high-pressure and low-pressure interfaces of the differential pressure transmitter (11); the back-blowing control component (13) realizes the switching of the measurement and back-blowing states through a three-way solenoid valve, and the back-blowing gas source is clean air.

5. The anti-blocking high-precision V-cone flowmeter with a two-stage throttling element according to claim 1 or 2, characterized in that: The flow balancing plate (3) is arranged at the inlet end face of the measuring cylinder (1); the inlet and outlet of the measuring cylinder (1) are both provided with mounting flanges (2).

6. The anti-blocking high-precision V-cone flowmeter with two-stage throttling element according to claim 1 or 2, characterized in that: The centers of the V-cone (4) and the flow equalizing plate (3) are both located on the central axis of the measuring cylinder (1); the distance between the tip of the V-cone (4) and the flow equalizing plate (3) is at least greater than twice the inner diameter of the measuring cylinder (1).

7. The anti-blocking high-precision V-cone flowmeter with a two-stage throttling element according to claim 1 or 2, characterized in that: A ring opening is formed between the periphery of the V-cone (4) and the inner wall of the measuring cylinder (1), and circular holes are evenly distributed on the flow equalizing plate (3); the diameter of the circular holes is not greater than the minimum width of the ring opening.

8. The anti-blocking high-precision V-cone flowmeter with two-stage throttling element according to claim 1 or 2, characterized in that: The wall-attached heating pipe sections on the high-pressure guiding pipe (6) and the low-pressure guiding pipe (7) are respectively coiled on the two ends of the measuring cylinder (1); the lengths of the wall-attached heating pipe sections on the high-pressure guiding pipe (6) and the low-pressure guiding pipe (7) are both at least 1 meter.

9. The anti-blocking high-precision V-cone flowmeter with a two-stage throttling element as claimed in claim 1 or 2, characterized in that: The non-wall-attached heating pipe sections of the high-pressure lead-in pipe (6) and the low-pressure lead-in pipe (7) are both coated with a thermal insulation layer.

10. An anti-blocking high-precision V-cone flowmeter with a two-stage throttling element as claimed in claim 1 or 2, characterized in that: The cylinder wall heater (5) is a cylinder structure with two halves spliced ​​together. The cylinder wall heater (5) is installed on the outer wall of the measuring cylinder (1) in close contact with the wall. The cylinder wall heater (5) is a cast aluminum heater.

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