Differential pressure flowmeter

Abstract

The utility model relates to the technical field of flow measurement and detection, in particular to a differential pressure flowmeter which comprises a first pipeline, a second pipeline and a pore plate arranged between the first pipeline and the second pipeline, fixing pipes are arranged on the side walls of the first pipeline and the second pipeline respectively, the bottoms of the fixing pipes are communicated with the first pipeline or the second pipeline, and the pore plate is arranged on the first pipeline or the second pipeline. A sealing pipe is arranged above the fixing pipe, a ball valve is arranged between the sealing pipe and the fixing pipe, the sealing pipe is communicated with the fixing pipe through the ball valve, a pressure taking pipe is sleeved with the fixing pipe, the pressure taking pipe is sleeved with the ball valve in a penetrating mode, the pressure taking pipe is movably sleeved with the sealing pipe in a sealed mode, and a differential pressure transmitter is arranged above the pressure taking pipe. A three-valve set is arranged between the differential pressure transmitter and the pressure tapping pipe, and the differential pressure transmitter is connected with the pressure tapping pipe through the three-valve set. The utility model provides a differential pressure flowmeter which is convenient to maintain, avoids influence caused by medium conveying and is used for overcoming the defects in the prior art.

Description

TECHNICAL FIELD

[0001] The utility model relates to flow measurement and detection technical field, concretely relates to a differential pressure flowmeter. BACKGROUND

[0002] Differential pressure flowmeter is a kind of flow measurement equipment based on fluid dynamics principle, it determines the instrument of the principle of the relationship between the pressure difference and flow generated when the medium of conveying flows through throttling device. The working principle of differential pressure flowmeter mainly relies on Bernoulli equation and fluid continuity equation. In practical application, differential pressure flowmeter is installed throttling device in pipeline, so that the flow rate of medium changes when the medium passes through the throttling device, thereby generating pressure difference before and after throttling device, by utilizing pressure sensor to measure this pressure difference, combined with Bernoulli equation and fluid continuity equation, the flow of fluid can be calculated. In order to convert the measured pressure difference into intuitive flow value, differential pressure flowmeter is usually equipped with corresponding conversion device or electronic equipment to convert and display signal, so as to facilitate the display, record or control of flow. Therefore, differential pressure flowmeter occupies an important position in industrial flow measurement due to its simple structure and low cost, so that differential pressure flowmeter becomes one of the most mature and most widely used instruments for measuring flow in current industrial production. There are various types of differential pressure flowmeters on the market, including but not limited to pitot tube flowmeter, orifice plate flowmeter, V-cone flowmeter, annubar flowmeter, venturi flowmeter, nozzle flowmeter, delta flowmeter and multi-orifice balanced flowmeter, etc.

[0003] Orifice plate flowmeter as a differential pressure flowmeter, it has the advantages of simple structure, easy maintenance, stable performance and high reliability, etc. in the gas, steam and liquid flow measurement in many fields. The throttling device of orifice plate flowmeter is composed of orifice plate with through hole. When the medium flows through the through hole on the orifice plate, the pressure difference between the two sides of the orifice plate will be generated. By using pressure sensor to measure the pressure difference, combined with Bernoulli equation and fluid continuity equation, the flow of fluid can be calculated. However, after a long time of use, due to the continuous impact of the medium, the orifice plate flowmeter may have problems such as wear, fouling or calibration drift, which may cause errors in the measurement of orifice plate flowmeter. In order to ensure that the measurement data of orifice plate flowmeter is consistent with the true flow, it is necessary to maintain the orifice plate flowmeter regularly. When maintaining the orifice plate flowmeter, if the pressure taking pipe of the orifice plate flowmeter is removed, the pipeline conveying medium needs to be closed first, and the orifice plate flowmeter can be maintained after the medium stops conveying. Although this method can meet the maintenance needs of flowmeter, but it needs to close the pipeline conveying medium, which will undoubtedly affect the medium conveying operation. Therefore, there is room for improvement in the practical application of orifice plate flowmeter to improve the maintenance convenience and avoid the influence of medium conveying, so as to better meet the needs of flow measurement. SUMMARY

[0004] In view of the shortcomings of the prior art, the utility model provides a differential pressure flowmeter which is convenient to maintain and avoids the influence of medium conveying.

[0005] The utility model employs the technical scheme that a differential pressure flowmeter, including pipeline one, pipeline two and the orifice plate who sets between pipeline one and pipeline two, the side wall of pipeline one and pipeline two respectively is provided with fixed pipe, the bottom of fixed pipe is linked with pipeline one or pipeline two, the top of fixed pipe is provided with sealed pipe, the ball valve is provided between sealed pipe and fixed pipe, sealed pipe is linked with fixed pipe through ball valve, fixed pipe is sleeved with pressure taking pipe, pressure taking pipe is worn in ball valve, pressure taking pipe is movable sealed and is installed in sealed pipe, the top of pressure taking pipe is provided with differential pressure transmitter, the three valve groups are provided between differential pressure transmitter and pressure taking pipe, differential pressure transmitter is connected with pressure taking pipe through three valve groups.

[0006] Preferably, the two ends of the ball valve are respectively installed on the fixed pipe and the sealed pipe, the ball valve is connected with the pipeline one or the pipeline two through the fixed pipe, a plurality of threaded holes are formed on the side wall of the sealed pipe away from the ball valve, the plurality of threaded holes are evenly formed on the side wall of the sealed pipe along the circumferential direction of the sealed pipe, a first bolt is threadedly sleeved in each of the plurality of threaded holes, and the pressure taking pipe is clamped on the sealed pipe through the first bolt.

[0007] Preferably, the sealing pipe is sequentially provided with a first compression ring, a packing ring and a second compression ring in the direction towards the ball valve, the first compression ring is threadedly sleeved in the sealing pipe, the first compression ring is located below the threaded hole, one side of the second compression ring is in contact with the ball valve, the packing ring is pressed between the first compression ring and the second compression ring, and the pressure taking pipe is movably and sealingly sleeved in the sealing pipe through the packing ring.

[0008] Preferably, the number of the fixed pipes, the ball valves, the sealing pipes and the pressure taking pipes is two, the two pressure taking pipes are respectively connected to two ends of the three-valve group, the two sealing pipes are respectively installed on one side of the two fixed pipes through the two ball valves, the two pressure taking pipes are respectively sleeved in the two fixed pipes, the other side of the two fixed pipes is respectively installed to the side wall of the pipeline one and the pipeline two, the pipeline one and the pipeline two are respectively provided with a sleeve hole, the fixed pipe is communicated with the pipeline one or the pipeline two through the sleeve hole, the sleeve hole is a stepped hole structure, the hole diameter of the side of the sleeve hole away from the fixed pipe is not greater than the hole diameter of the side of the sleeve hole close to the fixed pipe, the bottom of the pressure taking pipe is sleeved in the side of the sleeve hole close to the fixed pipe, and the outer diameter of the pressure taking pipe is matched with the hole diameter of the side of the sleeve hole close to the fixed pipe.

[0009] Preferably, the pipeline one and the pipeline two are respectively provided with a sealing hole, the sealing hole is communicated with the side of the sleeve hole close to the fixed pipe, the center of the sealing hole and the center of the sleeve hole are located on the same axial line, the hole diameter of the sealing hole is not less than the hole diameter of the sleeve hole, and the sealing ring made of elastic material is arranged in the sealing hole in an interference fit and sleeved on the pressure taking pipe.

[0010] Preferably, the pipeline one and the pipeline two are respectively provided with a flange plate, the flange plate is located on the side of the fixed pipe away from the hole plate, the center of the flange plate and the center of the pipeline one or the pipeline two are located on the same axial line, the flange plate and the pipeline one or the pipeline two are an integral structure, the flange plate is respectively provided with a long rod bolt, a nut is threadedly sleeved on the long rod bolt, and the flange plates connected to the pipeline one and the pipeline two are clamped on the long rod bolt through the nut.

[0011] Preferably, two gaskets made of elastic material are arranged between the pipeline one and the pipeline two, the gasket is a circular ring structure, the hole plate is located between the two gaskets, the side of the pipeline one close to the hole plate and the side of the pipeline two close to the hole plate are respectively provided with a fixing groove, one of the gaskets and one side of the hole plate are sleeved in the fixing groove of the pipeline one, the other gasket and the other side of the hole plate are sleeved in the fixing groove of the pipeline two, the middle part of the hole plate is provided with a through hole, the hole diameter of the through hole is not greater than the inner cavity diameter of the pipeline one or the inner cavity diameter of the pipeline two, and the pipeline one is communicated with the pipeline two through the through hole; the side of the through hole close to the pipeline two is a conical hole structure, and the side of the through hole close to the pipeline two gradually increases along the direction from the middle part of the through hole to the side close to the pipeline two.

[0012] The utility model has the advantages that: firstly, the utility model seals the outer side of the pressure tapping pipe by the sealing pipe, so that the medium conveyed by the pipeline one and the pipeline two cannot leak from the outer side of the pressure tapping pipe, and the pressure tapping pipe is taken out from the ball valve, and the ball valve is closed to seal the fixed pipe, so that the liquid leakage is avoided, the pressure tapping pipe is taken out for maintenance, the medium conveying is not affected, and the stability of the medium conveying is improved.

[0013] Secondly, the first bolt of the threaded sleeve in the threaded hole of the sealing pipe is used to press and fix the pressure tapping pipe to the sealing pipe, so that the pressure tapping pipe is assembled and disassembled.

[0014] Thirdly, the sleeve hole with the stepped hole structure is arranged on the pipeline one and the pipeline two, the insertion length of the pressure tapping pipe is limited, the pressure tapping pipe cannot be inserted into the pipeline one or the pipeline two, and the medium conveyed by the pipeline one and the pipeline two is not affected. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 It is a three-dimensional schematic view of the utility model.

[0016] Figure 2 It is a structural schematic view of the utility model.

[0017] Figure 3 It is Figure 2 It is an enlarged schematic view of the position A in the utility model.

[0018] Figure 4 It is Figure 2 It is an enlarged schematic view of the position B in the utility model.

[0019] Figure 5 It is Figure 2 It is an enlarged schematic view of the position C in the utility model.

[0020] Figure 6 It is an assembly schematic view of the pressure tapping pipe and the differential pressure transmitter in the utility model.

[0021] Figure 7 The assembly explosion drawing of the pipeline one and the pipeline two in the utility model.

[0022] Figure 8 The assembly explosion drawing of the sealing pipe and the first compression ring in the utility model. DETAILED DESCRIPTION

[0023] As Figures 1 to 8 shown in the figure, a differential pressure flowmeter, comprising a pipeline one 1, a pipeline two 2 and a orifice plate 3 arranged between the pipeline one 1 and the pipeline two 2, a fixed tube 4 is arranged on the side wall of the pipeline one 1 and the pipeline two 2 respectively, the bottom of the fixed tube 4 is communicated with the pipeline one 1 or the pipeline two 2, a sealing pipe 5 is arranged above the fixed tube 4, a ball valve 6 is arranged between the sealing pipe 5 and the fixed tube 4, the sealing pipe 5 is communicated with the fixed tube 4 through the ball valve 6, a pressure taking tube 7 is sleeved in the fixed tube 4, the pressure taking tube 7 is sleeved in the ball valve 6, the pressure taking tube 7 is movably sealed in the sealing pipe 5, a differential pressure transmitter 8 is arranged above the pressure taking tube 7, a three-valve group 9 is arranged between the differential pressure transmitter 8 and the pressure taking tube 7, and the differential pressure transmitter 8 is connected with the pressure taking tube 7 through the three-valve group 9. The outer side of the pressure taking tube 7 is sealed by the sealing pipe 5 arranged, so that the medium transported by the pipeline one 1 and the pipeline two 2 is prevented from leaking from the outer side of the pressure taking tube 7, and the sealing pipe 5 and the ball valve 6 are combined to be used, so that the pressure taking tube 7 is conveniently taken out for maintenance, the pressure taking tube 7 is moved out of the ball valve 6 and the fixed tube 4, the ball valve 6 is closed to quickly seal the fixed tube 4, so that the influence on the medium transportation is avoided, and after the pressure taking tube 7 is moved out of the ball valve 6 and the fixed tube 4, the bottom of the pressure taking tube 7 is controlled to be located in the sealing pipe 5 first, then the bottom of the pressure taking tube 7 is pulled out of the sealing pipe 5 after the ball valve 6 is closed, so that the leakage phenomenon is prevented in the process of taking out the pressure taking tube 7, the pressure taking tube is taken out for maintenance, the influence on the medium transportation is avoided, and the stability of the medium transportation is improved.

[0024] In the embodiment, the two ends of the ball valve 6 are respectively mounted on the fixed tube 4 and the sealing pipe 5, the ball valve 6 is connected with the pipeline one 1 or the pipeline two 2 through the fixed tube 4, a plurality of threaded holes 10 are formed in the side wall of the sealing pipe 5 away from the ball valve 6, the plurality of threaded holes 10 are evenly formed in the side wall of the sealing pipe 5 along the circumferential direction of the sealing pipe 5, a first bolt 11 is threadedly sleeved in each of the plurality of threaded holes 10, and the pressure taking tube 7 is clamped on the sealing pipe 5 through the first bolt 11, so that the pressure taking tube 7 is fixed on the sealing pipe 5.

[0025] Specifically, the sealing pipe 5 is sequentially provided with a first compression ring 12, a packing ring 13 and a second compression ring 14 in the direction towards the ball valve 6, the first compression ring 12 is threadedly sleeved in the sealing pipe 5, the first compression ring 12 is below the threaded hole 10, one side of the second compression ring 14 is in contact with the ball valve 6, the packing ring 13 is pressed between the first compression ring 12 and the second compression ring 14, the pressure taking pipe 7 is movably sealed and sleeved in the sealing pipe 5 through the packing ring 13, the outer side of the pressure taking pipe 7 is sealed by the sealing pipe 5, so as to avoid the medium in the pipeline one 1 and the pipeline two 2 from leaking out of the outer side of the pressure taking pipe 7; the top of the first compression ring 12 is provided with a limiting groove 15, the limiting groove 15 adopts a cross-shaped groove structure, a cross-shaped screwdriver or other tools are inserted into the limiting groove 15, so as to twist the first compression ring 12.

[0026] The two embodiments, the number of the fixed pipes 4, the ball valves 6, the sealing pipes 5 and the pressure taking pipes 7 are two, two pressure taking pipes 7 are respectively connected with two ends of the three-valve group 9, so as to facilitate the differential pressure transmitter 8 to detect the pressure difference between two measuring points, so as to facilitate the judgment of the flow of the medium, two sealing pipes 5 are respectively installed on one side of two fixed pipes 4 through two ball valves 6, two pressure taking pipes 7 are respectively sleeved in two fixed pipes 4, the other side of two fixed pipes 4 is respectively installed on the side wall of the pipeline one 1 and the pipeline two 2, the pipeline one 1 and the pipeline two 2 are respectively provided with a sleeve hole 16, the fixed pipe 4 is connected with the pipeline one 1 or the pipeline two 2 through the sleeve hole 16, the sleeve hole 16 adopts a stepped hole structure, the hole diameter of the side of the sleeve hole 16 away from the fixed pipe 4 is not greater than the hole diameter of the side of the sleeve hole 16 close to the fixed pipe 4, the bottom of the pressure taking pipe 7 is sleeved in the side of the sleeve hole 16 close to the fixed pipe 4, the outer diameter of the pressure taking pipe 7 is consistent with the hole diameter of the side of the sleeve hole 16 close to the fixed pipe 4, so as to avoid the pressure taking pipe 7 from extending into the pipeline one 1 or the pipeline two 2.

[0027] Please refer to Figure 5 , the pipeline one 1 and the pipeline two 2 are respectively provided with a sealing hole 17, the sealing hole 17 is connected with the side of the sleeve hole 16 close to the fixed pipe 4, the center of the sealing hole 17 and the center of the sleeve hole 16 are located on the same axis, the hole diameter of the sealing hole 17 is not less than the hole diameter of the sleeve hole 16, the sealing hole 17 is provided with an elastic material sealing ring 18, the sealing ring 18 is movably sealed and sleeved on the pressure taking pipe 7, so as to improve the sealing effect of the outer side of the pressure taking pipe 7 and improve the leakage prevention effect.

[0028] The flanges 19 are located on the outer side of the pipeline I 1 and the pipeline II 2, and are located on the side of the fixed tube 4 away from the hole plate 3. The center of the flange 19 and the center of the pipeline I 1 or the pipeline II 2 are located on the same axis. The flange 19 is an integral structure with the pipeline I 1 or the pipeline II 2. The long rod bolt 20 is arranged on the flange 19. The nut 21 is threadedly sleeved on the long rod bolt 20. The flange 19 connected with the pipeline I 1 and the flange 19 connected with the pipeline II 2 are clamped on the long rod bolt 20 through the nut 21, so that the pipeline I 1 and the pipeline II 2 are assembled together.

[0029] Please refer to Figure 2 and 5 , the pipeline I 1 and the pipeline II 2 are provided with two gaskets 22 made of elastic material. The gasket 22 adopts a circular ring structure. The hole plate 3 is located between the two gaskets 22, thereby sealing the two sides of the hole plate 3. The side of the pipeline I 1 close to the hole plate 3 and the side of the pipeline II 2 close to the hole plate 3 are provided with a fixing groove 23. One of the gaskets 22 and one side of the hole plate 3 are sleeved in the fixing groove 23 of the pipeline I 1. The other gasket 22 and the other side of the hole plate 3 are sleeved in the fixing groove 23 of the pipeline II 2. The width of the hole plate 3 is not less than the sum of the groove depths of the fixing groove 23 of the pipeline I 1 and the fixing groove 23 of the pipeline II 2. The middle part of the hole plate 3 is provided with a through hole 24. The hole diameter of the through hole 24 is not greater than the inner diameter of the pipeline I 1 or the inner diameter of the pipeline II 2. The pipeline I 1 is connected with the pipeline II 2 through the through hole 24. When the medium flows through the hole plate, the flow rate increases due to the reduction of the cross-sectional area, thereby generating a pressure difference before and after the hole plate. The pressure difference is proportional to the flow rate of the medium. The flow rate of the conveyed medium is calculated by measuring the pressure difference. The side of the through hole 24 close to the pipeline II 2 adopts a conical hole structure. The side of the through hole 24 close to the pipeline II 2 gradually increases from the middle part of the through hole 24 to the side close to the pipeline II 2. When the medium passes through the side of the through hole 24 close to the pipeline II 2, the flow rate of the medium gradually decreases, thereby improving the stability of the medium conveying and reducing the occurrence of measurement errors.

[0030] The assembly method of the product is as follows: as Figures 1 to 8As shown, before installing the product, the installation position of the product needs to be selected, and it is ensured that the product can be installed on the straight pipe section of the pipeline, and the length of the upstream straight pipe section of the product must be controlled to be at least ten times the pipe diameter of the pipeline one 1, and it is also ensured that the length of the downstream straight pipe section of the product is at least five times the pipe diameter of the pipeline two 2. This is done to avoid turbulence interference and to ensure the accuracy of flow measurement. When installing, first, the second compression ring 14, the packing ring 13 and the first compression ring 12 are placed in the sealing pipe 5 in sequence, and it is ensured that one side of the second compression ring 14 is in close contact with the ball valve 6, and the packing ring 13 is pressed between the first compression ring 12 and the second compression ring 14, so as to ensure the sealing effect of the sealing pipe 5. Next, the two gaskets 22 are respectively placed in the fixing grooves 23 respectively provided on the pipeline one 1 and the pipeline two 2, and the orifice plate 3 is placed between the two gaskets 22, and the pipeline one 1 and the pipeline two 2 are clamped and assembled together by using the long rod bolt 20 and the nut 21, so as to ensure that the pipeline one 1 and the pipeline two 2 are connected firmly. Subsequently, the product is placed on the selected installation position, and the outer side of the pipeline one 1 and the outer side of the pipeline two 2 are respectively welded and fixed to the pipeline by means of a welding tool such as a welding gun. After the welding is completed, the pressure tapping pipe 7 and the differential pressure transmitter 8 are respectively assembled to the three-valve group 9, the ball valve 6 is opened, and the pressure tapping pipe 7 is sequentially inserted into the sealing pipe 5, the ball valve 6, the fixed pipe 4 and the sleeve hole 16. The first bolt 11 is screwed into the threaded hole 10, so as to clamp the pressure tapping pipe 7 on the sealing pipe 5, thereby completing the assembly of the product. In addition, when the product needs to be maintained, the first bolt 11 is loosened first, and then the pressure tapping pipe 7 is removed from the ball valve 6 and the fixed pipe 4. During the removal of the pressure tapping pipe 7, first, the bottom of the pressure tapping pipe 7 is controlled to be located in the sealing pipe 5, and after the ball valve 6 is closed, the fixed pipe 4 is blocked, and then the bottom of the pressure tapping pipe 7 is pulled out from the sealing pipe 5, so as to be maintained.

[0031] Through the sealing of the outer side of the pressure tapping pipe 7 by the sealing pipe 5, the leakage of the medium transported by the pipeline one 1 and the pipeline two 2 from the outer side of the pressure tapping pipe 7 is avoided, and by using the ball valve 6, after the pressure tapping pipe 7 is taken out from the ball valve 6, the ball valve 6 is closed to block the fixed pipe 4, so as to avoid the leakage phenomenon, so as to take out the pressure tapping pipe for maintenance, and at the same time, the influence caused by the medium transportation is avoided, so as to improve the stability of the medium transportation.

[0032] The above-mentioned embodiments are only preferred embodiments of the present application, and are not limited to the scope of the present application. Any equivalent changes or modifications made according to the structure, features and principles described in the patent range of the present application should be included in the patent range of the present application.

Claims

1. A differential pressure flow meter comprising a conduit one (1), a conduit two (2) and an orifice (3) disposed between the conduit one (1) and the conduit two (2), characterised in that: The side wall of the pipeline one (1) and the pipeline two (2) is respectively provided with a fixed pipe (4), the bottom of the fixed pipe (4) is communicated with the pipeline one (1) or the pipeline two (2), the upper portion of the fixed pipe (4) is provided with a sealing pipe (5), the ball valve (6) is arranged between the sealing pipe (5) and the fixed pipe (4), the sealing pipe (5) is communicated with the fixed pipe (4) through the ball valve (6), the fixed pipe (4) is sleeved with a pressure taking pipe (7), the pressure taking pipe (7) is sleeved in the ball valve (6), the pressure taking pipe (7) is movably sleeved in the sealing pipe (5), the upper portion of the pressure taking pipe (7) is provided with a differential pressure transmitter (8), the differential pressure transmitter (8) and the pressure taking pipe (7) are provided with a three-valve group (9), and the differential pressure transmitter (8) is connected with the pressure taking pipe (7) through the three-valve group (9).

2. The differential pressure flow meter of claim 1, wherein: The two ends of the ball valve (6) are respectively mounted on the fixed pipe (4) and the sealing pipe (5), the ball valve (6) is connected with the pipeline one (1) or the pipeline two (2) through the fixed pipe (4), a plurality of threaded holes (10) are formed in the side wall of the sealing pipe (5) away from the ball valve (6), the threaded holes (10) are evenly formed in the side wall of the sealing pipe (5) along the circumferential direction of the sealing pipe (5), and the first bolt (11) is threadedly sleeved in the threaded hole (10).

3. The differential pressure flow meter of claim 2, wherein: The first pressure ring (12) is threadedly sleeved in the sealing pipe (5), the first pressure ring (12) is located below the threaded hole (10), one side of the second pressure ring (14) is in contact with the ball valve (6), the filler ring (13) is pressed between the first pressure ring (12) and the second pressure ring (14), and the pressure taking pipe (7) is movably sleeved in the sealing pipe (5) through the filler ring (13); the top of the first pressure ring (12) is provided with a limiting groove (15), and the limiting groove (15) has a cross groove structure.

4. The differential pressure flow meter of claim 1, wherein: The number of the fixed pipe (4), the ball valve (6), the sealing pipe (5) and the pressure taking pipe (7) is two, the two pressure taking pipes (7) are connected with the two ends of the three-valve group (9), the two sealing pipes (5) are mounted on one side of the two fixed pipes (4) through the two ball valves (6), the two pressure taking pipes (7) are sleeved in the two fixed pipes (4), the other side of the two fixed pipes (4) is mounted on the side wall of the pipeline one (1) and the pipeline two (2), the pipeline one (1) and the pipeline two (2) are provided with a sleeve hole (16), the fixed pipe (4) is communicated with the pipeline one (1) or the pipeline two (2) through the sleeve hole (16), the sleeve hole (16) has a stepped hole structure, the hole diameter of the side of the sleeve hole (16) away from the fixed pipe (4) is not greater than the hole diameter of the side of the sleeve hole (16) close to the fixed pipe (4), the bottom of the pressure taking pipe (7) is sleeved in the side of the sleeve hole (16) close to the fixed pipe (4), and the outer diameter of the pressure taking pipe (7) is consistent with the hole diameter of the side of the sleeve hole (16) close to the fixed pipe (4).

5. The differential pressure flow meter of claim 4, wherein: The pipeline one (1) and the pipeline two (2) are respectively provided with a sealing hole (17), the sealing hole (17) is communicated with the sleeve hole (16) on the side close to the fixed pipe (4), the center of the sealing hole (17) and the center of the sleeve hole (16) are on the same axial line, the aperture of the sealing hole (17) is not less than the aperture of the sleeve hole (16), the sealing ring (18) made of elastic material is arranged in the sealing hole (17) in an interference fit, and the sealing ring (18) is movably sealed on the pressure tapping pipe (7).

6. The differential pressure flow meter of claim 1, wherein: The pipeline one (1) and the pipeline two (2) are respectively provided with a sealing hole (17), the sealing hole (17) is communicated with the sleeve hole (16) on the side close to the fixed pipe (4), the center of the sealing hole (17) and the center of the sleeve hole (16) are on the same axial line, the aperture of the sealing hole (17) is not less than the aperture of the sleeve hole (16), the sealing ring (18) made of elastic material is arranged in the sealing hole (17) in an interference fit, and the sealing ring (18) is movably sealed on the pressure tapping pipe (7).

7. The differential pressure flow meter of claim 1, wherein: The pipeline one (1) and the pipeline two (2) are respectively provided with a sealing hole (17), the sealing hole (17) is communicated with the sleeve hole (16) on the side close to the fixed pipe (4), the center of the sealing hole (17) and the center of the sleeve hole (16) are on the same axial line, the aperture of the sealing hole (17) is not less than the aperture of the sleeve hole (16), the sealing ring (18) made of elastic material is arranged in the sealing hole (17) in an interference fit, and the sealing ring (18) is movably sealed on the pressure tapping pipe (7). The pipeline one (1) and the pipeline two (2) are respectively provided with a sealing hole (17), the sealing hole (17) is communicated with the sleeve hole (16) on the side close to the fixed pipe (4), the center of the sealing hole (17) and the center of the sleeve hole (16) are on the same axial line, the aperture of the sealing hole (17) is not less than the aperture of the sleeve hole (16), the sealing ring (18) made of elastic material is arranged in the sealing hole (17) in an interference fit, and the sealing ring (18) is movably sealed on the pressure tapping pipe (7).

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