A differential pressure flowmeter

Abstract

The application relates to the technical field of fluid metering, and discloses a differential pressure flowmeter which comprises a flow guide pipe, the two ends of the flow guide pipe are provided with variable-diameter pipes in a whole casting mode, liquid natural gas enters the inside of the flow guide device from a transportation pipeline during transportation, when passing through the left variable-diameter pipe, because the left end of the communication pipe is connected with the flow guide device close to the transportation pipeline, and the right end of the communication pipe is connected with the flow guide device close to the middle of the flow guide device, the pressure generated in the process that the fluid passes through the left and right ends of the communication pipe is different, under the fluid conduction in the communication pipe, different pressures act on the two sides of the pressure sensing sheet, the pressure difference is output from the output end of the pressure sensing sheet and connected with the input end of a flow display in data mode, so that the flow display can identify the pressure size borne by the pressure sensing sheet, calculate the flow speed and the flow, and the variable-diameter pipe in the shape of a circular truncated cone can slow down the resistance to the liquid natural gas and minimize the pressure loss.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fluid metering, in particular to a differential pressure flowmeter. BACKGROUND

[0002] The flowmeter is a kind of device used to measure the volume of liquid or gas passing through the pipeline per unit time, which plays a very important role in metallurgical chemical industry, medical equipment, construction, water conservancy and natural gas transportation. Commonly used flowmeters for pipeline transportation include differential pressure flowmeters, rotameters, ultrasonic flowmeters, vortex flowmeters and various types of flowmeters. Among them, the differential pressure flowmeter is the most widely used due to its simple structure.

[0003] The principle of the differential pressure flowmeter is to use a throttling device, a pressure taking device and a differential pressure conversion instrument. When the transported medium passes through the throttling device, it is subjected to resistance, and the pressure sensitive resistor of the pressure taking device is deformed under the action of the resistance, so that the pressure data is converted into flow data by the differential pressure conversion instrument and displayed. The whole process takes a short time, requires a small number of workpiece components, and reduces the cost of use and maintenance.

[0004] Although the existing differential pressure flowmeter has the above-mentioned many advantages, but in the actual use process still has certain limitation, because the orifice plate in the throttling device has small diameter, causes its to the pipeline inside transported medium flow obvious hindering effect, causes the pressure loss to be big, has the influence to the transportation efficiency of the transported medium, because the throttling device has small diameter, has higher request to the size of the impurities carried in the transported medium, has certain use limitation, and the fluid flow rate improves and forms vortex behind the orifice plate, thereby affecting the accuracy of the pressure taking device. To this end, the present application proposes a differential pressure flowmeter to solve the above-mentioned problems. SUMMARY

[0005] The present application proposes a differential pressure flowmeter, which has the advantage of small pressure loss of fluid in the pipeline, to solve the problem of large fluid resistance of traditional differential pressure flowmeter affecting the transportation efficiency.

[0006] In order to achieve the above object, the technical scheme adopted by the present application is as follows: a differential pressure flowmeter, comprising a flow guide device, both ends of the flow guide device are fixedly sleeved with a conveying pipeline through shaft hole matching, the outer surface of the conveying pipeline is provided with a connecting groove through lathe milling slot at a position close to one end, the outer surface of the connecting groove is provided with a mounting groove through lathe milling slot, the inside of the mounting groove is sleeved with a sealing ring, the outer surface of the conveying pipeline is provided with a connecting ring through integral casting at a position close to the connecting groove, the outer surface of the connecting ring is provided with a thread, and the thread is matched with the flow guide device, the top of the outer surface of the flow guide device is fixedly installed with a detection device through welding, the detection device is communicated with the inner cavity of the flow guide device, the left end of the detection device is close to the conveying pipeline at the communication position of the flow guide device, the right end of the detection device is close to the middle of the flow guide device at the communication position of the flow guide device, and the inside of the flow guide device is movably installed with a rotating device through sliding matching.

[0007] Further, the flow guide device comprises a flow guide pipe, both ends of the flow guide pipe are provided with a reducing pipe through integral casting, the shape of the reducing pipe is the same as that of a circular truncated cone, one end of the reducing pipe is fixedly installed with a connecting pipe through welding, the outer surface of the connecting pipe is provided with a sliding groove through lathe milling slot at a position close to one end, the outer surface of the sliding groove is movably sleeved with a connecting sleeve through shaft hole matching, the inner wall of the connecting sleeve is provided with a connecting thread, the inner wall of the flow guide pipe is fixedly installed with a fixed ring through welding at a position close to one end, one end of the fixed ring is fixedly installed with a limiting sleeve through welding, the outer surface of the limiting sleeve is provided with a flow guide hole through drilling bed drilling, the flow guide holes are distributed in an annular array, the outer surface of the flow guide holes is movably installed with a rotating device through sliding matching, and the outer surface of the limiting sleeve is provided with a stroke limiting ring through integral casting at a position close to one end.

[0008] Further, the detection device comprises a fixed pipe, the inner wall of the fixed pipe is fixedly installed with a pressure sensing sheet through clamping at a position close to the middle, the outer surface of the fixed pipe is fixedly sleeved with a flow display device through bolt connection, both ends of the fixed pipe are fixedly installed with a communication pipe through bolt connection, one end of the communication pipe is fixedly connected with the outer surface of the reducing pipe, the left end of the communication pipe is close to the conveying pipeline at the connection position of the flow guide device, and the right end of the communication pipe is close to the middle of the flow guide device at the connection position of the flow guide device.

[0009] Further, the output end of the pressure sensing sheet is connected with the input end of the flow display device in a wired signal connection mode.

[0010] Further, the rotating device comprises a stroke ring movably installed outside the limiting sleeve through a sliding fit, the outer side of the stroke ring is movably sleeved with a tapered rotating pipe through a bearing connection, the cross section shape of the tapered rotating pipe is the same as that of the variable diameter pipe, the outer surface of the tapered rotating pipe is provided with a communication hole through drilling, the tapered rotating pipe is fixedly installed with a brush at the position between the communication holes through clamping, the inner wall of the tapered rotating pipe is fixedly installed with a fan blade at the position between the communication holes through welding, one side of the stroke ring is fixedly installed with a spring through clamping, and one end of the spring is fixedly connected with the fixed ring through clamping.

[0011] Further, the spring is in a compressed state initially, and the stroke ring and the stop ring are in contact under the action of the spring.

[0012] Further, when the fluid flow rate inside the fixed pipe is slow, the friction between the stroke ring and the stop ring prevents the overall rotation of the rotating device, and when the fluid flow rate inside the fixed pipe is fast, the rotating device is displaced under the impact of the fluid, and the stroke ring and the stop ring are out of contact.

[0013] The application has the following beneficial effects.

[0014] 1. The fluid passes through the variable diameter pipe to change the flow rate, thereby forming a pressure difference and acting on both sides of the pressure sensing sheet to obtain the pressure value, and the flow rate is calculated by the pressure value to realize the metering effect. The variable diameter pipe is in the shape of a circular truncated cone, which can reduce the resistance to the fluid, and compared with the traditional orifice plate flowmeter, the pressure loss is minimized.

[0015] 2. In the case of low flow rate, the fluid can pass through the gap between the tapered rotating pipe and the variable diameter pipe and enter the inside of the flow guide pipe through the flow guide hole, so that the fluid can flow closer to the connection between the communication pipe and the variable diameter pipe during the flow process, ensuring that the pressure difference can be better transmitted to the pressure sensing sheet through the medium inside the fixed pipe. In the case of high flow rate, the stroke ring and the stop ring are out of contact, the rotating device rotates as a whole, and the outer surface of the brush will be in contact with the inner wall of the left variable diameter pipe, thereby continuously cleaning the inner wall.

[0016] 3. The brush will continuously contact the connection between the variable diameter pipe and the communication pipe, and will hinder the conduction of pressure during the contact, so that the pressure difference sensed by the pressure sensing sheet presents a periodic change. The shorter the cycle frequency detected by the rotating device, the larger the fluid flow in the pipeline, and vice versa. The detection result of the pressure difference can improve the accuracy of the final result.

[0017] 4, The device involved in the application has less obstruction to fluid flow, avoids the influence of the traditional differential pressure flowmeter and the vortex flowmeter on the detection results due to the small aperture or the obvious obstruction of the working member to the fluid, and improves the detection precision of the device. BRIEF DESCRIPTION OF DRAWINGS

[0018] The accompanying drawings, which form a part of the specification, illustrate the embodiments of the present application and serve to explain the principles of the present application.

[0019] The present disclosure can be more clearly understood and appreciated from the following detailed description, taken in conjunction with the following drawings, in which:

[0020] Figure 1 is a structural schematic diagram of the present application;

[0021] Figure 2 is a right view of the structure of the present application;

[0022] Figure 3 is a structural schematic diagram of the present application Figure 2 is a sectional view in the direction of A-A of the present application;

[0023] Figure 4 is a structural schematic diagram of the present application

[0024] Figure 5 is a structural schematic diagram of the present application

[0025] Figure 6 is a right view of the structure of the present application;

[0026] Figure 7 is a structural schematic diagram of the present application Figure 6 is a sectional view in the direction of B-B of the present application;

[0027] Figure 8 is a structural schematic diagram of the present application

[0028] Figure 9 is a right view of the structure of the present application;

[0029] Figure 10 is a structural schematic diagram of the present application Figure 9 is a sectional view in the direction of C-C of the present application;

[0030] Figure 11 is a structural schematic diagram of the present application

[0031] Figure 12 is a front view of the structure of the present application;

[0032] Figure 13 is a structural schematic diagram of the present application Figure 12 is a sectional view in the direction of D-D of the present application;

[0033] Figure 14 For the structure of the stroke ring and the matching connection diagram of the stop ring;

[0034] Figure 15 For the pressure-time relationship diagram obtained by the measurement experiment of pure water in a 35cm diameter pipeline at low flow rate and room temperature;

[0035] Figure 16 For the pressure-time relationship diagram obtained by the measurement experiment of pure water in a 35cm diameter pipeline at high flow rate and room temperature.

[0036] In the figure; 1, flow guide device; 11, flow guide pipe; 12, reducing pipe; 13, connecting pipe; 14, sliding groove; 15, connecting sleeve; 16, connecting thread; 17, fixing ring; 18, limiting sleeve; 19, flow guide hole; 101, stop ring; 2, transport pipeline; 3, connecting groove; 4, mounting groove; 5, sealing ring; 6, connecting ring; 7, detection device; 71, fixed tube; 72, pressure sensing sheet; 73, flow display; 74, communication pipe; 8, rotating device; 81, stroke ring; 82, conical rotating pipe; 83, communication hole; 84, brush; 85, fan blade; 86, spring. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0038] A differential pressure flowmeter, please refer to Figures 1-4 , including flow guide device 1, both ends of flow guide device 1 are fixedly sleeved with transport pipeline 2 through shaft hole matching mode, the outer surface of transport pipeline 2 is close to the position of one end and is provided with connecting groove 3 through lathe milling groove mode, the outer surface of connecting groove 3 is provided with mounting groove 4 through lathe milling groove mode, the inside of mounting groove 4 is sleeved with sealing ring 5, the outer surface of transport pipeline 2 is close to the position of connecting groove 3 and is provided with connecting ring 6 through integral casting mode, the outer surface of connecting ring 6 is provided with thread, and the thread is matched with flow guide device 1, the top of the outer surface of flow guide device 1 is fixedly installed with detection device 7 through welding mode, detection device 7 is communicated with the inner cavity of flow guide device 1, the left end of detection device 7 is close to transport pipeline 2 at the communication part of flow guide device 1, the right end of detection device is close to the middle of flow guide device 1 at the communication part of flow guide device, and rotating device 8 is movably installed in the inside of flow guide device 1 through sliding fit mode.

[0039] Please refer to Figures 5-7, the flow guide device 1 includes the flow guide pipe 11, both ends of the flow guide pipe 11 are provided with the reducing pipe 12 in a way of integral casting, fluid will enter the inside of the flow guide device 1 from the conveying pipe 2 in the process of transportation, in the process of passing through the left reducing pipe 12, due to the reduction of pipe diameter, the fluid flow rate is accelerated, the pressure on the inner wall of the left reducing pipe 12 is increased, in the process of passing through the right reducing pipe 12, due to the increase of pipe diameter, the fluid flow rate is slowed down, the pressure on the inner wall of the right reducing pipe 12 is reduced, the pressure acts on both sides of the pressure sensing sheet 72 through the communicating pipe 74, since the left end of the communicating pipe 74 is close to the conveying pipe 2 at the connection of the flow guide device 1, the right end of the communicating pipe 74 is close to the middle of the flow guide device 1 at the connection of the flow guide device 1, by Bernoulli's law and the influence of pipe diameter reduction on fluid pressure, it can be concluded that the fluid will form a pressure difference at both ends of the detection device 7 when passing through the reducing pipe 12 at both ends, the reducing pipe 12 has the same shape as a circular truncated cone, one end of the reducing pipe 12 is fixedly installed with the connecting pipe 13 in a way of welding, the outer surface of the connecting pipe 13 is close to one end and is provided with the sliding groove 14 in a way of lathe milling, the outer surface of the sliding groove 14 is movably sleeved with the connecting sleeve 15 in a way of shaft hole cooperation, the inner wall of the connecting sleeve 15 is provided with the connecting thread 16, the inner wall of the flow guide pipe 11 is close to one end and is fixedly installed with the fixed ring 17 in a way of welding, one end of the fixed ring 17 is fixedly installed with the limiting sleeve 18 in a way of welding, the outer surface of the limiting sleeve 18 is provided with the flow guide hole 19 in a way of drilling machine drilling, the flow guide hole 19 is distributed in a ring array, the outer surface of the flow guide hole 19 is movably installed with the rotating device 8 in a way of sliding cooperation, the outer surface of the limiting sleeve 18 is close to one end and is provided with the stroke ring 101 in a way of integral casting.

[0040] Please refer to Figure 3 , Figures 8-10 and Figure 14 , the detection device 7 includes the fixed pipe 71, the inner wall of the fixed pipe 71 is close to the middle and is fixedly installed with the pressure sensing sheet 72 in a way of clamping, the outer surface of the fixed pipe 71 is fixedly sleeved with the flow display 73 in a way of bolt connection, both ends of the fixed pipe 71 are fixedly installed with the communicating pipe 74 in a way of bolt connection, one end of the communicating pipe 74 is fixedly connected with the outer surface of the reducing pipe 12, the left end of the communicating pipe 74 is close to the conveying pipe 2 at the connection of the flow guide device 1, the right end of the communicating pipe 74 is close to the middle of the flow guide device 1 at the connection of the flow guide device 1, and the fluid in the communicating pipe 74 acts on both sides of the pressure sensing sheet 72, so that the pressure sensing sheet 72 is deformed, since the faster the flow rate of the fluid in the conveying pipe 2 and the flow guide device 1 is, the greater the force on the inner wall of the reducing pipe 12 is, the greater the pressure difference on both sides of the pressure sensing sheet 72 is, experimental data are as follows Figure 14The output end of the pressure sensing sheet 72 is connected to the input end of the flow display 73 through wired signal connection, so that the flow display 73 can identify the deformation degree of the pressure sensing sheet 72 and the pressure size, thereby calculating the specific flow rate and flow of the fluid. This measurement method avoids the large resistance to fluid and serious pressure loss caused by the small aperture of the traditional differential pressure flowmeter, which has a certain influence on the transportation effect. The variable diameter pipe 12 in the application can reduce the resistance to fluid, and compared with the traditional orifice plate flowmeter, the pressure loss can be minimized.

[0041] Please refer to Figure 10 The output end of the pressure sensing sheet 72 is connected to the input end of the flow display 73 through wired signal connection.

[0042] Please refer to Figures 5-14 The rotating device 8 includes a stroke ring 81 which is movably installed on the outside of the limiting sleeve 18 through sliding fit, and the outside of the stroke ring 81 movably sheathes a conical rotating pipe 82 through bearing connection. The cross-sectional shape of the conical rotating pipe 82 is the same as that of the variable diameter pipe 12, and the outer surface of the conical rotating pipe 82 is provided with communication holes 83 through drilling. When the flow rate of the fluid in the flow guide device 1 and the transportation pipeline 2 is slow, the overall displacement of the rotating device 8 cannot be caused by the small thrust of the fluid, and the fluid can pass through the gap between the conical rotating pipe 82 and the variable diameter pipe 12 and enter the inside of the flow guide pipe 11 through the flow guide hole 19, so that the fluid can be closer to the connection between the communication pipe 74 and the variable diameter pipe 12 during flow, the pressure difference can be better transmitted to the pressure sensing sheet 72 through the medium in the fixed pipe 71, and the problem of inaccurate measurement caused by pressure loss is avoided. The outer surface of the conical rotating pipe 82 is fixedly installed with brushes 84 through clamping at the positions between the communication holes 83, and the inner wall of the conical rotating pipe 82 is fixedly installed with fan blades 85 through welding at the positions between the communication holes 83. One side of the stroke ring 81 is fixedly installed with a spring 86 through clamping, and one end of the spring 86 is fixedly connected with the fixed ring 17 through clamping. When the flow rate of the fluid in the flow guide device 1 and the transportation pipeline 2 is fast, the overall displacement of the rotating device 8 is caused by the thrust of the fluid, so that the stroke ring 81 is separated from the contact with the stop ring 101, and the fluid acts on the fan blades 85 to generate torque, thereby driving the overall rotation of the rotating device 8. In this process, the outer surface of the brush 84 will be in contact with the inner wall of the left variable diameter pipe 12, thereby continuously cleaning the inner wall, avoiding the problem of reduced pipe diameter at the connection between the communication pipe 74 and the variable diameter pipe 12 due to attachments, causing loss in the process of pressure conduction, thereby improving the stability of the device during operation.

[0043] Please refer to Figure 7And Figure 13 The spring 86 is initially in a compressed state, and the travel ring 81 is in contact with the stop ring 101 under the action of the spring 86.

[0044] Please refer to Figure 3 , Figure 7 , Figure 10 , Figure 13 And Figure 15 When the fluid flow rate in the fixed pipe 71 is slow, the friction between the travel ring 81 and the stop ring 101 prevents the rotation device 8 from rotating as a whole, and when the fluid flow rate in the fixed pipe 71 is fast, the rotation device 8 is displaced under the impact of the fluid, and the travel ring 81 and the stop ring 101 are out of contact. During the overall rotation of the rotation device 8, the brush 84 is in constant contact with the connection between the variable-diameter pipe 12 and the communication pipe 74, and hinders the conduction of pressure when in contact, so that the pressure difference sensed by the pressure sensing sheet 72 presents periodic changes. Since the rotation speed of the rotation device 8 is directly proportional to the fluid flow rate in the flow guide device 1 and the transport pipeline 2, as shown in the experimental data Figure 15 , the shorter the cycle frequency detected by the rotation device 8, the greater the fluid flow rate in the pipeline, and vice versa. The measured data can further calibrate the data measured by the differential pressure principle, avoid the decrease in measurement accuracy caused by travel vortex at high flow rate (the trigger threshold is related to the initial spring force of the spring, which can be determined according to different fluids and requirements during manufacturing. The principles of low flow rate and high flow rate in this paper are the same, and the effects are opposite. The results are that the travel ring and the stop ring remain in contact, and the torque cannot overcome the friction to drive the rotation device to rotate), and further improve the measurement accuracy of the device.

[0045] Among them, the device involved in the present application has less resistance to fluid flow, avoiding the influence of vortex formed after high-speed fluid passing due to small aperture or obvious resistance of working parts to fluid in traditional differential pressure flowmeter and vortex flowmeter, improving the detection accuracy of the device.

[0046] The use method of the present application is as follows:

[0047] During use, the connection between the flow guide device 1 and the transport pipeline 2 is achieved by the rotation of the connecting sleeve 15 and the effect of the threaded connection with the connecting ring 6, and the sealing ring 5 can ensure the sealing of the connection between the flow guide device 1 and the transport pipeline 2. During the transportation of the fluid, the fluid enters the inside of the flow guide device 1 from the transport pipeline 2, and during the process of passing through the left reducing pipe 12, the fluid flow rate increases due to the decrease in pipe diameter, and the pressure on the inner wall of the left reducing pipe 12 increases. During the process of passing through the right reducing pipe 12, the fluid flow rate decreases due to the increase in pipe diameter, and the pressure on the inner wall of the left reducing pipe 12 decreases. The pressure acts on both sides of the pressure sensing sheet 72 through the communication pipe 74. Since the left communication is close to the transport pipeline 2, and the right communication is close to the middle of the flow guide device 1, according to Bernoulli's law and the influence of pipe diameter change on fluid pressure, it can be concluded that when the fluid passes through the two end reducing pipes 12, a pressure difference will be formed at both ends of the detection device 7, and the fluid inside the communication pipe 74 will act on both sides of the pressure sensing sheet 72, causing the pressure sensing sheet 72 to deform. Since the faster the fluid flow rate inside the transport pipeline 2 and the flow guide device 1 is, the greater the force acting on the inner wall of the reducing pipe 12, the greater the pressure difference on both sides of the pressure sensing sheet 72, and the output end of the pressure sensing sheet 72 is connected to the input end of the flow display 73 through a wired signal connection, so that the flow display 73 can recognize the deformation degree of the pressure sensing sheet 72 and calculate the specific flow rate and flow of the fluid. When the fluid flow rate inside the flow guide device 1 and the transport pipeline 2 is slow, the overall thrust of the rotating device 8 is small, which cannot cause the rotating device 8 to displace, and the fluid can pass through the gap between the tapered rotating pipe 82 and the reducing pipe 12 and enter the inside of the flow guide pipe 11 through the flow guide hole 19, so that the fluid flow process can be closer to the connection between the communication pipe 74 and the reducing pipe 12, ensuring that the pressure difference can be better transmitted to the pressure sensing sheet 72 through the medium inside the fixed pipe 71. When the fluid flow rate inside the flow guide device 1 and the transport pipeline 2 is fast, the overall rotating device 8 displaces under the push of the fluid, causing the travel ring 81 to disengage from the contact with the stop ring 101, and the fluid acts on the fan blade 85 to generate torque, thereby driving the overall rotating device 8 to rotate. In this process, the outer surface of the brush 84 will be in contact with the inner wall of the left reducing pipe 12, thereby continuously cleaning the inner wall. During the overall rotation of the rotating device 8, the brush 84 will continuously contact the connection between the reducing pipe 12 and the communication pipe 74, and hinder the conduction of pressure during the contact, thereby causing the pressure difference sensed by the pressure sensing sheet 72 to be periodic. Since the rotational speed of the overall rotating device 8 is directly proportional to the fluid flow rate inside the flow guide device 1 and the transport pipeline 2, if the period frequency detected by the rotating device 8 is shorter, it means that the fluid flow rate in the pipeline is larger, and vice versa. The measured data can further calibrate the data measured by the pressure difference principle at high flow rates.

Claims

1. A differential pressure flow meter, characterized in that, The device includes a flow guiding device (1), on the top of the outer surface of the flow guiding device (1) a detection device (7) is fixedly installed, the detection device (7) is connected to the inner cavity of the flow guiding device (1), the end of the detection device (7) near the fluid inlet is connected to the flow guiding device (1) near the transport pipe (2), the end of the detection device (7) away from the fluid inlet is connected to the flow guiding device (1) near the middle of the flow guiding device (1), a rotating device (8) is movably installed inside the flow guiding device (1), the flow guiding device (1) includes a flow guiding pipe (11), both ends of the flow guiding pipe (11) are provided with reducing pipes (12), the other end of the reducing pipe (12) is fixedly installed with a connecting pipe (13), ... The diameter pipe (12) has the same shape as a truncated cone. A fixing ring (17) is fixedly installed on the inner wall of the guide pipe (11) near the fluid inlet. A limiting sleeve (18) is fixedly installed on the end of the fixing ring (17) facing the fluid inlet. The outer surface of the limiting sleeve (18) is provided with guide holes (19) that are connected inside and outside. The guide holes (19) are distributed in a ring array. A rotating device (8) is movably installed on the side of the guide holes (19) near the inner wall of the diameter pipe (12). A stop ring (101) is provided on the outer surface of the limiting sleeve (18) near the fluid inlet. The rotating device (8) includes a stroke ring (81). The stroke ring (81) is movably installed on the limiting sleeve. (18) On the outside of the stroke ring (81), a conical rotating tube (82) is movably sleeved on the outside of the stroke ring (81). The cross-section of the conical rotating tube (82) through the axis has the same shape as the cross-section of the variable diameter tube (12) through the axis. A connecting hole (83) is opened on the outer surface of the conical rotating tube (82) and the inner and outer surfaces are connected. A brush (84) is fixedly installed on the outer surface of the conical rotating tube (82) at the position between the connecting holes (83). A fan blade (85) is fixedly installed on the inner wall of the conical rotating tube (82) at the position between the connecting holes (83). A spring (86) is fixedly installed on one side of the stroke ring (81). One end of the spring (86) is fixedly connected to the fixed ring (17). The spring (86) is initially in the position of In the compressed state, the stroke ring (81) and the stop ring (101) come into contact under the action of the spring (86). During the rotation of the rotating device (8), the brush (84) will continuously come into contact with the connection between the reducer (12) and the connecting pipe (74), and will hinder the transmission of pressure when in contact, so that the pressure difference sensed by the pressure sensor (72) will show a periodic change. Since the rotation speed of the rotating device (8) is directly proportional to the fluid flow rate inside the guide device (1) and the transport pipe (2), if the period frequency detected by the rotating device (8) is shorter, it means that the fluid flow rate in the pipe is larger, and vice versa. The measured data can be further calibrated for the data measured by the differential pressure principle.

2. A differential pressure flow meter according to claim 1, characterized in that, The detection device (7) includes a fixed tube (71), a pressure sensor (72) is fixedly installed on the inner wall of the fixed tube (71) near the middle, a flow display (73) is fixedly sleeved on the outer surface of the fixed tube (71), and connecting tubes (74) are fixedly installed at both ends of the fixed tube (71). One end of the connecting tube (74) is fixedly connected to the outer surface of the reducing pipe (12). The connection point between the end of the connecting tube (74) near the fluid inlet and the flow guiding device (1) is close to the transport pipe (2), and the connection point between the end of the connecting tube (74) away from the fluid inlet and the flow guiding device (1) is close to the middle of the flow guiding device (1). Both ends of the flow guiding device (1) are fixedly sleeved with transport pipes (74). 2) A connecting groove (3) is provided on the outer surface of the transport pipe (2) near the end of the flow guiding device (1). An installation groove (4) is provided on the outer surface of the connecting groove (3). A sealing ring (5) is fitted inside the installation groove (4). A connecting ring (6) is provided on the outer surface of the transport pipe (2) near the connecting groove (3). The outer surface of the connecting ring (6) is provided with a thread, and the thread cooperates with the flow guiding device (1). A sliding groove (14) is provided on the outer surface of the connecting pipe (13) away from the reducing pipe (12). A connecting sleeve (15) is movably fitted on the outer surface of the sliding groove (14). A connecting thread (16) is provided on the inner wall of the connecting sleeve (15).

3. A differential pressure flow meter according to claim 2, characterized in that, The output end of the pressure sensor (72) is connected to the input end of the flow display (73) via a wired signal connection.

4. A differential pressure flow meter according to claim 1, characterized in that, The spring (86) is initially in a compressed state, and the stroke ring (81) and the stop ring (101) come into contact under the action of the spring (86).

5. A differential pressure flow meter according to claim 2, characterized in that, When the fluid flow rate inside the fixed pipe (71) is slow, the friction between the stroke ring (81) and the stop ring (101) prevents the rotating device (8) from rotating as a whole. When the fluid flow rate inside the guide pipe (11) is fast, the rotating device (8) is displaced under the action of fluid impact, and the stroke ring (81) and the stop ring (101) disengage.

Images