Orifice plate flowmeter and method of use thereof

Abstract

The application relates to the technical field of flow meters, and discloses an orifice flow meter and an application method thereof, which comprise a rear-end pipe, an orifice and a front-end pipe, wherein the rear-end pipe comprises a rear pipe body, a positioning ring and an inner hem; the positioning ring is fixedly arranged in the rear pipe body; the inner hem is arranged in the rear pipe body, one end of the inner hem is integrally formed with one end of the rear pipe body and is continuously arranged; the orifice is fixedly arranged between the positioning ring and the inner hem; the front-end pipe is coaxially arranged with the rear pipe body, and one end of the front-end pipe is welded and fixed on the outer side of the inner hem. The rear-end pipe is arranged to comprise the rear pipe body, the positioning ring and the inner hem, the orifice and the rear-end pipe are fixed first, and then the rear pipe body and the front-end pipe are connected, so that the orifice flow meter is conveniently assembled, the installation precision of the orifice is guaranteed, and the detection precision of the orifice flow meter is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of flow meters, in particular to an orifice flow meter and an application method thereof. BACKGROUND

[0002] The orifice flow meter is a differential pressure flow measuring instrument based on the throttling principle. When fluid flows through the throttling device (orifice) in the pipeline, the flow beam will form a local contraction at the orifice, thereby increasing the flow rate and reducing the static pressure, generating a certain pressure difference before and after the orifice. By measuring this pressure difference and combining the known geometric parameters of the pipeline and the orifice and the physical property parameters of the fluid, the flow rate of the fluid can be calculated.

[0003] The orifice flow meter has the advantages of simple structure, wide adaptability and high standardization, and is widely used in the fields of petroleum chemical industry, power, metallurgy, heating and heating, etc. For example, the welding orifice flow meter with ring chamber pressure taking disclosed in the patent with the publication number CN112113623B sets the orifice between the front clamping ring and the rear clamping ring, and sets the pressure taking pipes on both sides of the orifice. The pressure difference on both sides of the orifice is measured by the cooperation of the two pressure taking pipes and the pressure difference measuring equipment, so as to detect the flow rate of the medium in the measuring pipe.

[0004] In the above technical solution, in order to fix the orifice, the front clamping ring and the rear clamping ring need to be welded and fixed, and the welding positions of the front clamping ring and the rear clamping ring need to avoid the position of the orifice. However, this technical solution also needs to set the front ring chamber, the rear ring chamber and the groove for communication, which not only leads to relatively large processing difficulty of the front clamping ring, the rear clamping ring and the orifice, but also is not easy to guarantee the processing precision of the front clamping ring, the rear clamping ring and the orifice, which is not conducive to improving the detection precision of the orifice flow meter. SUMMARY

[0005] Therefore, the present application provides an orifice flow meter and an application method thereof, which can not only reduce the processing difficulty of the rear end pipe and the front end pipe, but also improve the installation precision of the orifice, so as to guarantee the detection precision of the orifice flow meter.

[0006] The technical solution of the present application is realized in the following way. On the one hand, the present application provides an orifice flow meter, which comprises a rear end pipe, an orifice and a front end pipe. The rear end pipe comprises a rear pipe body, a positioning ring and an inner hem. The positioning ring is fixedly arranged in the rear pipe body. The inner hem is arranged in the rear pipe body, one end of the inner hem is integrally formed and continuously arranged with one end of the rear pipe body. The orifice is fixed between the positioning ring and the inner hem. The front end pipe is coaxially arranged with the rear pipe body, and one end of the front end pipe is welded and fixed on the outer side of the inner hem.

[0007] On the basis of the above technical scheme, preferably, the inner flange is in a spiral shape in cross section, and the inner flange abuts against the inner wall of the rear pipe body.

[0008] More preferably, the inner flange and the rear pipe body form a winding cavity, and a plurality of communication grooves are formed in the end of the inner flange away from the rear pipe body, and the winding cavity and the interior of the rear pipe body are connected through the communication grooves.

[0009] More preferably, the rear end pipe further comprises a plurality of abutting portions, the plurality of abutting portions correspond to the plurality of communication grooves one by one, one end of the abutting portion is integrally formed in the communication groove, and the abutting portion is continuously arranged with the inner flange, and the abutting portion abuts against the hole plate.

[0010] More preferably, a limiting groove is formed in the hole plate, and the side surface of the abutting portion is clamped with the limiting groove.

[0011] More preferably, the limiting groove comprises an arc surface and an inclined surface, the inclined surface and the arc surface are both inner walls of the limiting groove, and both abut against the abutting portion; the inclined surface is located on the side of the arc surface away from the rear pipe body, the inclined surface is tangent to the arc surface, the minimum distance between the inclined surface and the positioning ring is a, the minimum distance between the arc surface and the positioning ring is b, and a < b.

[0012] More preferably, the front end pipe comprises a front pipe body and an arc-shaped closing portion, one end of the arc-shaped closing portion is integrally formed in the end of the front pipe body and continuously arranged with the same, and the other end of the arc-shaped closing portion abuts against the abutting portion; the circumferential side of the arc-shaped closing portion abuts against the inner flange, and the two form a V-shaped welding groove, and the rear end pipe and the front end pipe are fixedly connected through the welding material in the welding groove.

[0013] On the basis of the above technical scheme, preferably, a positioning structure is arranged between the hole plate and the positioning ring.

[0014] On the basis of the above technical scheme, preferably, two pressure taking pipes are further included, and the two pressure taking pipes are respectively fixedly arranged in the rear end pipe and the front end pipe.

[0015] In a second aspect, the present application provides a method for using the orifice plate flowmeter, comprising the following steps: S1, connecting the rear end pipe and the front end pipe to the pipeline to be measured; S2, connecting the two pressure tapping pipes to the differential pressure measuring device; S3, conducting the pipeline to be measured, allowing the medium in the pipeline to pass through the orifice plate, and calculating the flow rate of the medium in the pipeline by the differential pressure measuring device; S4, cutting off the pipeline to be measured, emptying the medium in the pipeline, and removing the differential pressure measuring device, and spraying cleaning gas or protective oil onto the orifice plate through the two pressure tapping pipes.

[0016] The orifice plate flowmeter and the method for using the same have the following beneficial effects over the prior art:

[0017] (1) By setting the rear end pipe to include a rear pipe body, a positioning ring, and an inner flange, the orifice plate and the rear end pipe can be fixed first, and then the rear end pipe and the front end pipe can be connected, which facilitates the assembly of the orifice plate flowmeter and ensures the installation accuracy of the orifice plate, thereby improving the detection accuracy of the orifice plate flowmeter.

[0018] (2) By setting the inner flange to be spiral-shaped, the heat deformation of the inner flange can strengthen the fixing firmness of the orifice plate when the inner flange is welded to the front end pipe, and by setting the abutting portion and the limiting groove, the rotation or shaking of the orifice plate during use can be avoided, thereby ensuring the fixing stability and firmness of the orifice plate.

[0019] (3) By opening the communication groove, the winding cavity can be connected to the inside of the rear pipe body, thereby avoiding the problem of inaccurate detection caused by the existence of air bubbles in the winding cavity.

[0020] (4) By setting the front end pipe to include a front pipe body and an arc-shaped closing portion, the arc-shaped closing portion and the inner flange can be combined to form a V-shaped welding groove, thereby improving the welding convenience and quality of the front end pipe and the rear end pipe. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0022] Figure 1 is a sectional view of the orifice plate flowmeter of the present application.

[0023] Figure 2 is Figure 1 is an enlarged view of A in FIG.

[0024] Figure 3 isometric view of the back pipe body in the orifice flowmeter of the present application.

[0025] Figure 4 cross-sectional view of the inner bead in the orifice flowmeter of the present application.

[0026] Figure 5 isometric view of the inner bead in the orifice flowmeter of the present application.

[0027] Figure 6 isometric view of the back pipe body in the orifice flowmeter of the present application.

[0028] Figure 7 isometric view of the orifice plate in the orifice flowmeter of the present application.

[0029] Figure 8 cross-sectional view of the limiting groove in the orifice flowmeter of the present application.

[0030] Figure 9 isometric view of the positioning ring in the orifice flowmeter of the present application.

[0031] Figure 10 isometric view of the back pipe body in the orifice flowmeter of the present application.

[0032] Figure 11 isometric view of the front pipe body in the orifice flowmeter of the present application.

[0033] Figure 12 isometric view of the orifice flowmeter of the present application.

[0034] wherein: 1, back pipe body; 11, back pipe body; 12, positioning ring; 13, inner bead; 14, abutting part; 101, winding cavity; 102, communication groove; 2, orifice plate; 201, limiting groove; 2011, arc surface; 2012, inclined surface; 202, positioning structure; 3, front pipe body; 31, front pipe body; 32, arc-shaped closeout; 301, welding groove; 4, pressure tapping pipe. DETAILED DESCRIPTION

[0035] The technical solutions in the present application will be described clearly and completely below in conjunction with the specific embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those of ordinary skill in the art without creative work, fall within the protection scope of the present application.

[0036] As Figure 1 and Figure 12As shown, the orifice plate flowmeter of the present application comprises a rear-end pipe 1, an orifice plate 2, a front-end pipe 3 and two pressure taps 4. The rear-end pipe 1 and the front-end pipe 3 are of the same specification of circular pipe structure, coaxially arranged and sealingly communicated, combined into a sealed pipe structure; the end of the rear-end pipe 1 away from the front-end pipe 3 and the end of the front-end pipe 3 away from the rear-end pipe 1 are both provided with flanges so as to be connected with the pipeline to be measured.

[0037] The orifice plate 2 is of a circular ring plate structure, sealingly fixed in the rear-end pipe 1, and the two pressure taps 4 are respectively fixed in the rear-end pipe 1 and the front-end pipe 3. After the medium in the pipeline to be measured enters the front-end pipe 3, the medium flow will form a local contraction at the center hole of the orifice plate 2, so as to increase the flow rate of the medium and reduce the static pressure, and a certain pressure difference is generated before and after the orifice plate 2. The pressure difference and the flow rate of the fluid have a certain functional relationship. After the two pressure taps 4 are connected with the pressure difference detection equipment, the pressure difference can be measured, and the flow rate of the fluid can be calculated by using the pressure difference. The pressure difference detection equipment is the prior art, such as differential pressure transmitter.

[0038] The rear-end pipe 1 and the front-end pipe 3 provide a long enough passage for the medium flow, so that the flow of the medium in the pipeline to be measured is stable enough, and the throttling effect of the orifice plate 2 is guaranteed.

[0039] As shown in Figure 4 and Figure 5 The rear-end pipe 1 comprises a rear pipe body 11, a positioning ring 12 and an inner hem 13. The positioning ring 12 is of a circular ring plate structure, and its inner diameter is greater than that of the orifice plate 2. The positioning ring 12 is fixedly arranged in the rear pipe body 11, and the side surface of the positioning ring 12 is perpendicular to the axis of the rear pipe body 11.

[0040] After the orifice plate 2 is placed in the rear pipe body 11, the end of the rear pipe body 11 is hemmed by using a hemming machine, so as to bend the end of the rear pipe body 11 inwardly, forming the inner hem 13 in the rear pipe body 11. The inner hem 13 abuts against the orifice plate 2, so as to fixedly abut the orifice plate 2 between the positioning ring 12 and the inner hem 13.

[0041] In the above manner, the fixing of the orifice plate 2 and the rear-end pipe 1 can be realized before the welding and fixing of the front-end pipe 3 and the rear-end pipe 1, so as to guarantee the installation precision of the orifice plate 2.

[0042] The end of the inner hem 13 is integrally formed with and continuously arranged on the end of the rear pipe body 11. The inner hem 13 can be quickly processed by using the hemming of the rear pipe body 11. Compared with the prior art, the structure of the rear-end pipe 1 is simpler and can be quickly processed, so as to help improve the processing efficiency of the orifice plate flowmeter.

[0043] The connection between the orifice plate 2 and the rear-end pipe 1 is not a traditional welding fixation, and the orifice plate 2 can be disassembled, replaced or recycled by bending or cutting the inner curled edge 13, thereby improving the maintenance convenience and recycling performance of the orifice flowmeter.

[0044] After the orifice plate 2 is fixed in the rear-end pipe 1, the front-end pipe 3 is coaxial with the rear pipe body 11, and one end of the front-end pipe 3 is welded and fixed on the outside of the inner curled edge 13, thereby realizing the connection and fixation of the front-end pipe 3 and the rear-end pipe 1.

[0045] The cross section of the inner curled edge 13 is spiral-shaped, as shown in Figure 4 The inner curled edge 13 abuts against the inner wall of the rear pipe body 11, thereby improving the structural strength of the inner curled edge 13 and ensuring the fixing firmness of the orifice plate 2. Only 3 / 4 of the inner curled edge 13 is shown in the figure, and the end of the inner curled edge 13 abuts against the inner wall of the rear pipe body 11, which can ensure the structural strength of the inner curled edge 13. In actual production process, the number of turns of the inner curled edge 13 can be appropriately increased to avoid problems such as inward collapse of the inner curled edge 13 during assembly.

[0046] Since the welding position of the front-end pipe 3 and the rear pipe body 11 is not on the position of the orifice plate 2, the welding operation will not affect the orifice plate 2, and the welding seam can be conveniently detected to ensure the assembly quality of the orifice flowmeter.

[0047] At the same time, when the front-end pipe 3 and the rear pipe body 11 are welded, the inner curled edge 13 will be deformed after being heated, resulting in outward expansion of the inner curled edge 13, thereby further improving the abutting firmness of the inner curled edge 13 to the orifice plate 2.

[0048] As shown in Figure 5 The inner curled edge 13 and the rear pipe body 11 form a winding cavity 101, and during the processing of the inner curled edge 13, there will be a gap between the local inner curled edge 13 and the rear pipe body 11. During the use of the orifice flowmeter, the medium in the rear pipe body 11 will not quickly fill the winding cavity 101, resulting in the existence of a certain gas in the winding cavity 101. The gas will flow into the winding cavity 101 in the form of bubbles in an intermittent manner, affecting the detection accuracy of the orifice flowmeter.

[0049] In order to solve the above problems, a plurality of communication grooves 102 are arranged at the end of the inner curled edge 13 away from the rear pipe body 11, and the winding cavity 101 and the inside of the rear pipe body 11 are connected through the communication grooves 102. When the rear-end pipe 1 and the front-end pipe 3 are connected to the pipe to be measured, and the medium to be measured flows through the orifice flowmeter, the medium can quickly fill the winding cavity 101, avoiding the existence of bubbles to affect the detection accuracy of the orifice flowmeter.

[0050] In order to improve the efficiency of the medium filling the winding cavity 101, that is, improve the exhaust efficiency of the gas inside the winding cavity 101, at least one communication groove 102 should be located at the top of the inner curl 13.

[0051] As shown in Figure 2 , the rear-end tube 1 further comprises a plurality of abutting portions 14, which correspond one-to-one with the plurality of communication grooves 102. One end of the abutting portion 14 is integrally formed in the communication groove 102 and is continuously arranged with the inner curl 13, and the abutting portion 14 abuts against the orifice plate 2. As shown in Figure 6 , the abutting portion 14 is obtained by slotting and bending the inner curl 13, and the bending direction of the abutting portion 14 is opposite to the bending direction of the end of the inner curl 13 away from the rear tube body 11. The cooperation of the abutting portion 14 and the inner curl 13 can further increase the range of the orifice plate 2 being abutted, thereby helping to improve the fixing firmness of the orifice plate 2.

[0052] At the same time, the abutting portion 14 can also partially shield the communication groove 102, reducing the impact on the inner wall of the winding cavity 101 when the medium first flows into the winding cavity 101, thereby protecting the orifice plate flowmeter and the pipeline to be measured.

[0053] The pressure tapping pipe 4 on the front-end tube 3 can also be fixedly penetrated through the rear tube body 11, and the pressure tapping pipe 4 corresponds to the position of the winding cavity 101. During use of the device, the inner curl 13 can wrap and protect the end of the pressure tapping pipe 4, and the gap between the abutting portion 14 and the inner curl 13 not only forms a filtering structure to prevent impurities from entering the pressure tapping pipe 4, but also ensures the stability of the change of fluid pressure.

[0054] As shown in Figure 2 and Figure 7 , a limiting groove 201 is formed on the orifice plate 2, and the side surface of the abutting portion 14 is clamped with the limiting groove 201, thereby avoiding the rotation of the orifice plate 2 during use, so as to ensure the detection accuracy of the orifice plate flowmeter. The limiting groove 201 is also provided with a plurality of limiting grooves 201, and the plurality of limiting grooves 201 correspond one-to-one with the plurality of abutting portions 14.

[0055] Similarly, as shown in Figure 9 , a positioning structure 202 is arranged on the positioning ring 12, and a corresponding positioning structure 202 is arranged on the orifice plate 2. The two positioning structures 202 can be a recess and a protrusion clamped with each other. When the inner curl 13 is processed, the positioning structure 202 can prevent the orifice plate 2 from rotating relative to the positioning ring 12, thereby ensuring the installation accuracy of the orifice plate 2, so as to smoothly complete the subsequent assembly work.

[0056] The limiting groove 201 comprises an arc surface 2011 and an inclined surface 2012. The arc surface 2011 is a circular arc surface, and the inclined surface 2012 is a plane. The inclined surface 2012 is inclined to the side surface of the orifice plate 2.Figure 2 As shown, the inclined surface 2012 and the arc surface 2011 are inner walls of the limiting groove 201, and the inclined surface 2012 and the arc surface 2011 are in abutment with the abutting portion 14. Figure 8 As shown, the inclined surface 2012 is located on the side of the arc surface 2011 away from the rear pipe body 11, and the inclined surface 2012 is tangent to the arc surface 2011. Assuming that the minimum distance between the inclined surface 2012 and the positioning ring 12 is a, and the minimum distance between the arc surface 2011 and the positioning ring 12 is b, then a < b.

[0057] When installing the orifice plate 2, first, a slot is formed on the end of the rear pipe body 11, then the end of the rear pipe body 11 is crimped for a distance, then the abutting portion 14 is bent in the direction opposite to the bending direction of the inner crimping 13 by using a tool, and finally the end of the rear pipe body 11 is continuously crimped, so as to form the rear end pipe 1 as shown. Figures 2-6

[0058] In the above processing process, as shown, the end of the abutting portion 14 first extends into the limiting groove 201 from above the arc surface 2011, and the abutting portion 14 forms a bent structure through the guidance of the arc surface 2011. When the rear pipe body 11 is continuously crimped, the end of the abutting portion 14 first moves to the inclined surface 2012 and then moves out of the limiting groove 201. Figure 8

[0059] The above-mentioned arc surface 2011 and inclined surface 2012 will not hinder the movement of the end of the abutting portion 14, and the above-mentioned arc surface 2011 and inclined surface 2012 can adapt to abutting portions 14 of different lengths to avoid affecting the assembly of the orifice plate flowmeter. Of course, the end of the abutting portion 14 after processing is preferably extended out of the limiting groove 201.

[0060] Compared with the cuboid-shaped groove body, the limiting groove 201 can adapt to the excessively long abutting portion 14 to avoid that the excessively long abutting portion 14 cannot extend out of the limiting groove 201. Compared with the arc-shaped groove body, the limiting groove 201 can increase the span of the abutting portion 14 in the radial direction of the orifice plate 2 in the limiting groove 201, thereby improving the connection reliability of the limiting groove 201 and the orifice plate 2.

[0061] As shown in Figure 2 , Figure 4 ,and Figure 11 ,the front end pipe 3 comprises a front pipe body 31 and an arc-shaped closing portion 32. The arc-shaped closing portion 32 can be obtained by necking the end of the front pipe body 31, so that one end of the arc-shaped closing portion 32 is integrally formed on the end of the front pipe body 31 and is continuously arranged with the end of the front pipe body 31.

[0062] As shown in Figure 2 ,​​​As shown, the arc-shaped closing 32 is in abutment with the abutting portion 14 away from the one end of the front pipe body 31, so that the abutting portion 14 can be extruded and fixed, and the fixing firmness of the abutting portion 14 and the hole plate 2 is improved.

[0063] As shown, Figure 2 and Figure 4 As shown, the arc-shaped side wall of the arc-shaped closing 32 is in partial abutment with the arc-shaped side wall of the inner hem 13, so that the connection sealing property and the connection stability of the front end pipe 3 and the rear end pipe 1 can be effectively improved.

[0064] As shown, Figure 4 and Figure 12 As shown, the arc-shaped closing 32 and the inner hem 13 further form a V-shaped welding groove 301, and the rear end pipe 1 and the front end pipe 3 are fixedly connected through the welding material in the welding groove 301, and the V-shaped welding groove 301 can improve the welding convenience of the rear end pipe 1 and the front end pipe 3, so that the molten material of the welding material can quickly fill the welding groove 301, thereby helping to improve the welding efficiency and the welding quality of the rear end pipe 1 and the front end pipe 3.

[0065] As shown, Figure 1 As shown, the inner diameter of the arc-shaped closing 32 gradually decreases from right to left, and the inner wall is smooth and continuous, so that the medium can be well guided to maintain the flow stability of the medium.

[0066] The use method of the hole plate flowmeter and the application method thereof is as follows:

[0067] S1, the flanges of the rear end pipe 1 away from the hole plate 2 and the front end pipe 3 away from the hole plate 2 are respectively installed in the to-be-measured pipeline, so that the rear end pipe 1 and the front end pipe 3 are in sealed communication with the to-be-measured pipeline.

[0068] S2, the two pressure taking pipes 4 are connected with the differential pressure measuring device, so that the two detection ends of the differential pressure measuring device are respectively in communication with the inside of the rear end pipe 1 and the inside of the front end pipe 3.

[0069] S3, the to-be-measured pipeline is conducted, so that the medium in the to-be-measured pipeline enters the front end pipe 3 and the rear end pipe 1 and flows through the hole plate 2, at this time, the hole plate 2 partially shrinks the medium flow, so that the medium at both sides of the hole plate 2 forms a pressure difference, and through the measurement of the differential pressure measuring device and the functional relationship between the pressure difference and the flow, the flow of the medium in the to-be-measured pipeline can be calculated.

[0070] S4, when the medium in the pipeline to be measured stops conveying, there will be some medium residues or stains on the surface of the orifice plate 2, if not cleaned in time, it will cause the surface of the orifice plate 2 to rust, adhere to solid impurities and other problems, affect the detection accuracy of the orifice plate 2. Therefore, after cutting off the pipeline to be measured, the medium in the pipeline to be measured is first emptied, then the differential pressure measuring device connected with the two pressure tapping pipes 4 is disassembled, and finally clean gas or protective oil is sprayed on the orifice plate 2 through the two pressure tapping pipes 4 to flush and protect the orifice plate 2, thereby prolonging the service life of the orifice plate 2.

[0071] The above merely describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An orifice flow meter characterized by: It comprises a rear end pipe (1), a hole plate (2) and a front end pipe (3), wherein, The rear end pipe (1) comprises a rear pipe body (11), a positioning ring (12) and an inner hem (13), the positioning ring (12) is fixedly arranged in the rear pipe body (11); the inner hem (13) is arranged in the rear pipe body (11), one end of the inner hem (13) is integrally formed with one end of the rear pipe body (11) and is continuously arranged; The hole plate (2) is fixedly arranged between the positioning ring (12) and the inner hem (13); The front end pipe (3) is coaxially arranged with the rear pipe body (11), and one end of the front end pipe (3) is welded and fixed on the outer side of the inner hem (13); The cross section of the inner hem (13) is spiral, and the inner hem (13) abuts against the inner wall of the rear pipe body (11); The inner hem (13) and the rear pipe body (11) form a winding cavity (101); a plurality of communication grooves (102) are formed in the end of the inner hem (13) away from the rear pipe body (11), and the winding cavity (101) and the inside of the rear pipe body (11) are connected through the communication grooves (102); The rear end pipe (1) further comprises a plurality of abutting portions (14), the plurality of abutting portions (14) correspond to the plurality of communication grooves (102) one by one, one end of the abutting portion (14) is integrally formed in the communication groove (102) and is continuously arranged with the inner hem (13), and the abutting portion (14) abuts against the hole plate (2); A limiting groove (201) is formed in the hole plate (2), the side surface of the abutting portion (14) is clamped with the limiting groove (201); The limiting groove (201) comprises an arc surface (2011) and an inclined surface (2012), the inclined surface (2012) and the arc surface (2011) are both inner walls of the limiting groove (201) and abut against the abutting portion (14); the inclined surface (2012) is located on the side of the arc surface (2011) away from the rear pipe body (11), the inclined surface (2012) is tangent to the arc surface (2011), the minimum distance between the inclined surface (2012) and the positioning ring (12) is a, the minimum distance between the arc surface (2011) and the positioning ring (12) is b, and a < b; The front end pipe (3) comprises a front pipe body (31) and an arc-shaped closing portion (32), one end of the arc-shaped closing portion (32) is integrally formed at the end of the front pipe body (31) and is continuously arranged, the other end of the arc-shaped closing portion (32) abuts against the abutting portion (14); the circumferential side of the arc-shaped closing portion (32) abuts against the inner hem (13), and they form a V-shaped welding groove (301), and the rear end pipe (1) and the front end pipe (3) are fixedly connected through the welding material in the welding groove (301).

2. An orifice plate flow meter as claimed in claim 1, wherein: A positioning structure (202) is arranged between the hole plate (2) and the positioning ring (12).

3. An orifice plate flow meter as claimed in claim 1, wherein: Two pressure tapping pipes (4) are further included, and the two pressure tapping pipes (4) are respectively fixed on the rear end pipe (1) and the front end pipe (3).

4. The method of using an orifice plate flow meter of claim 3, wherein, The method comprises the following steps: S1, one end of the rear end pipe (1) and one end of the front end pipe (3) away from the orifice plate (2) are communicated and arranged in a pipeline to be measured; S2, two pressure tapping pipes (4) are connected with a differential pressure measuring device; S3, the pipeline to be measured is conducted, the medium in the pipeline to be measured passes through the orifice plate (2), and the flow of the medium in the pipeline to be measured is calculated through the differential pressure measuring device; S4, the pipeline to be measured is cut off, the medium in the pipeline to be measured is emptied, and the differential pressure measuring device is removed, and clean gas or protective oil is sprayed on the orifice plate (2) through the two pressure tapping pipes (4).

Images