Small-diameter differential pressure type flowmeter for narrow space

Abstract

The invention discloses a small-diameter differential pressure type flowmeter for a narrow space, and belongs to the technical field of flowmeters.The small-diameter differential pressure type flowmeter comprises a shell, a conveying pipe is arranged in the shell, a flow instrument is arranged on the shell, a connecting rod is arranged on the bottom face of the flow instrument, the bottom end of the connecting rod penetrates through the shell to be inserted into the conveying pipe, and connecting pipes are fixed to the two ends of the conveying pipe; the two ends of the shell are fixed to the connecting piece, a through opening is formed in the side face of the connecting piece, the through opening is communicated with the connecting pipe, and a pipe fitting is fixed to the end face, away from the connecting pipe, of the connecting piece, and is characterized in that a mounting groove is formed in the inner side face of the through opening, and a blocking plate used for adjusting the size of the through opening is vertically and slidably arranged in the mounting groove; the connecting piece is provided with a driving mechanism used for driving the blocking plate to move in the vertical direction. The device has the effect of conveniently fixing the adjusted position of the plugging plate.

Description

Technical Field

[0001] The invention relates to the technical field of flow meters, in particular to a small-diameter differential pressure flow meter for a narrow space. Background Art

[0002] The differential pressure flowmeter is based on the throttling principle of fluid flow and realizes flow measurement by utilizing the pressure difference generated when the fluid flows through the throttling device. It is one of the most mature and commonly used methods for measuring flow in production. It is usually composed of a throttling device that can convert the measured flow into a pressure differential signal and a differential pressure gauge and display instrument that can convert the pressure differential into the corresponding flow value for display. In the unit combination instrument, the pressure differential signal generated by the throttling device is often converted into a corresponding standard signal (electrical or pneumatic) through a differential pressure transmitter for display, recording or control.

[0003] In the related art, a Chinese utility model patent with announcement number CN218765412U discloses a differential pressure flowmeter, including a detection mechanism and a fixed structure; connecting structures are respectively installed at both ends of the detection mechanism, and the interior of the connecting structure is movably connected with a reciprocating structure and a control mechanism, and the control mechanism is fitted with the reciprocating structure, and the reciprocating structure includes a lap block, a slider and a guide rod, the lap blocks are arranged in three groups, and the bottoms of the three groups of lap blocks are respectively fixedly connected with sliders, and the sliders are slidably connected to the guide rods; the fixed structure is fixedly connected to the top of the connecting structure, and the fixed structure is movably connected to the control mechanism at the same time.

[0004] With respect to the above-mentioned related technologies, the movement of the overlapping blocks is controlled by a control mechanism so that after the overlapping blocks are fitted together, the overlapping blocks can form a whole, and the liquid can enter the interior of the delivery pipe after passing through the hollow groove, and the hollow groove B and the reserved groove are arranged in a stepped shape, so that the water flow in the delivery pipe can be adjusted by the overlapping blocks. When the control mechanism adjusts the position of the overlapping blocks, the control mechanism is fixed by the fixed structure, so that the adjusted position of the overlapping blocks is fixed, and then the fixing of the adjusted overlapping blocks is more cumbersome. Summary of the invention

[0005] In order to improve the problem of complicated adjustment and fixation of the overlap blocks, the present application provides a small-diameter differential pressure flowmeter for use in a narrow space.

[0006] The present application provides a small diameter differential pressure flow meter for narrow space using the following technical solution: A small-diameter differential pressure flowmeter for a narrow space comprises a shell, a delivery pipe is arranged in the shell, a flow meter is arranged on the shell, a connecting rod is arranged on the bottom surface of the flow meter, the bottom end of the connecting rod passes through the shell and is inserted into the delivery pipe, connecting pipes are fixed at both ends of the delivery pipe, both ends of the shell are fixed to a connecting piece, a through opening is provided on the side of the connecting piece, the through opening is communicated with the connecting pipe, a pipe fitting is fixed on the end surface of the connecting piece away from the connecting pipe, and the characteristic is that: an installation groove is provided on the inner side surface of the through opening, a sealing plate for adjusting the size of the through opening is vertically slidably arranged in the installation groove, and a driving mechanism for driving the sealing plate to move vertically is provided on the connecting piece.

[0007] By adopting the above technical solution, when it is necessary to adjust the water flow in the delivery pipe, the driving mechanism drives the sealing plate to move vertically to adjust the size of the opening, thereby adjusting the size of the water flow in the delivery pipe. When the size of the water flow is adjusted, there is no need to fix the driving mechanism, thereby making it easier to adjust and fix the position of the sealing plate.

[0008] Preferably, a through hole is provided on the inner top surface of the mounting groove, and the driving mechanism includes a moving rod fixed to the top surface of the sealing plate, the top end of the moving rod passes through the through hole, a driving tube is rotatably installed on the top surface of the connecting piece, the top end of the moving rod is inserted in the driving tube, the moving rod is threadedly connected to the driving tube, and a driving component for driving the driving tube to rotate is provided on the connecting piece.

[0009] By adopting the above technical solution, when it is necessary to adjust the size of the water flow in the connecting pipe, the driving component is started, the driving component drives the driving pipe to rotate, the driving pipe drives the moving rod to move vertically, and the moving rod drives the sealing plate to move vertically, thereby adjusting the size of the opening, and then adjusting the size of the water flow in the connecting pipe.

[0010] Preferably, an installation box is fixed to the top surface of the connecting member, the driving tube is located in the installation box, the driving assembly includes a bevel gear 1 arranged on the driving tube, a rotating shaft is passed through the side of the installation box, the rotating shaft is rotatably connected to the installation box, a bevel gear 2 is arranged at one end of the rotating shaft close to the bevel gear 1, the bevel gear 1 is meshed with the bevel gear 2, and a rotating block is fixed to one end of the rotating shaft away from the installation box.

[0011] By adopting the above technical solution, the rotating block is rotated, the rotating block drives the rotating shaft to rotate, the rotating shaft drives the second bevel gear to rotate, the second bevel gear drives the first bevel gear to rotate, the first bevel gear drives the driving tube to rotate, the driving tube drives the moving rod to move vertically, and the moving rod drives the blocking plate to move vertically, so as to facilitate the adjustment of the size of the opening. Since the driving tube is threadedly connected with the moving rod, when the rotating block stops rotating, the moving rod and the driving tube are self-locking, so that it is easier to fix the blocking plate after the position adjustment is completed.

[0012] Preferably, a plurality of scale lines are arranged on the side of the installation box, and the plurality of scale lines are arranged at equal intervals along the circumference of the rotating shaft, and an indicator needle is fixed to the side of the rotating block close to the installation box.

[0013] By adopting the above technical solution, a pointer is set on the rotating block. When the rotating block stops rotating, the pointer on the rotating block points to the scale line, so that the staff can adjust the sizes of the openings on both sides of the connecting pipe to be consistent.

[0014] Preferably, an annular groove 1 is formed on the inner circumferential surface of the pipe, and a filter screen is arranged in the annular groove 1.

[0015] By adopting the above technical solution, a filter screen is arranged in the pipe fitting to filter the water flowing into the connecting pipe from the pipe fitting, thereby reducing the influence of impurities in the water on the use of the flow meter.

[0016] Preferably, a through groove is provided on the outer circumferential surface of the pipe fitting, an arc-shaped plate 1 is arranged in the through groove, the arc-shaped plate 1 is arranged in the through groove, an annular groove 2 is provided on the inner circumferential surface of the arc-shaped plate 1, the edge of the upper half of the filter screen is inserted in the annular groove 2, and a fixing part for fixedly connecting with the arc-shaped plate 1 is provided on the pipe fitting.

[0017] By adopting the above technical solution, when the filter plate needs to be cleaned, the fixings between the pipe fitting and the arc plate 1 are removed, and the arc plate 1 is removed from the pipe fitting, thereby facilitating the removal of the filter net from the pipe fitting to clean impurities.

[0018] Preferably, the fixing member includes two fixing blocks 1 fixed on the outer circumferential surface of the pipe fitting, a stud is fixed on the top surface of the fixing block 1, an arc plate 2 is fixed on the outer circumferential surface of the arc plate 1, two fixing blocks 2 are fixed on the outer circumferential surface of the arc plate 2, the two fixing blocks 2 are respectively located at two ends of the arc plate 2, a circular hole is opened on the top surface of the fixing block 2, the top end of the stud passes through the circular hole, a nut is sleeved on the stud, the nut is threadedly connected to the stud, and the bottom surface of the nut abuts against the top surface of the fixing block 2.

[0019] By adopting the above technical solution, when the filter is installed in the arc groove one, the arc plate one is aligned with the through groove, the circular hole on the fixing plate two is aligned with the stud, the arc plate one is installed in the through groove, the outer peripheral surface of the upper half of the filter is inserted in the arc groove two, the top of the stud passes through the circular hole, and then the nut is sleeved on the stud, and the nut is rotated so that the bottom surface of the nut abuts against the top surface of the fixing plate two, thereby fixing the arc plate one on the round tube.

[0020] Preferably, the inner circumference of the arc plate 2 is in contact with the outer circumference of the pipe fitting, the outer circumference of the pipe fitting is provided with an annular groove 3, the annular groove 3 is located on the circumferential side of the through groove, the inner circumference of the arc plate 2 is provided with an annular groove 4, a sealing ring is fixed in the annular groove 3, and the top end of the sealing ring is inserted in the annular groove 4.

[0021] By adopting the above technical solution, when the arc plate 1 is fixed on the pipe fitting, the inner circumference of the arc plate 2 fits with the outer circumference of the pipe fitting, and the sealing ring is inserted into the annular groove 4, thereby sealing the connection between the arc plate 1 and the pipe fitting, thereby reducing the possibility of water leakage at the connection between the arc plate 1 and the pipe fitting.

[0022] Preferably, a plurality of round rods are fixed to the side of the filter screen away from the blocking plate.

[0023] By adopting the above technical solution, a plurality of round rods are fixed on the side of the filter screen away from the sealing plate. When the filter screen filters impurities, the impurities are clamped between adjacent round rods, thereby facilitating the removal of the filter screen from the pipe fitting and reducing the possibility of impurities falling into the pipe fitting, thereby facilitating the cleaning of the impurities.

[0024] In summary, the present application includes at least one of the following beneficial technical effects: 1. When the water flow in the connecting pipe needs to be adjusted, the rotating block is rotated, the rotating block drives the rotating shaft to rotate, the rotating shaft drives the second bevel gear to rotate, the second bevel gear drives the first bevel gear to rotate, the first bevel gear drives the driving pipe to rotate, the driving pipe drives the moving rod to move vertically, the moving rod drives the blocking plate to move vertically, so as to adjust the size of the opening to adjust the water flow in the connecting pipe. Since the driving pipe and the moving rod are threadedly connected, when the rotating block stops rotating, the moving rod and the driving pipe are self-locked, so that it is easier to fix the blocking plate after the position adjustment is completed; 2. When installing the filter in the arc groove 1, align the arc plate 1 with the through groove, align the round hole on the fixing plate 2 with the stud, install the arc plate 1 in the through groove, insert the outer peripheral surface of the upper half of the filter into the arc groove 2, and let the top of the stud pass through the round hole. Then put the nut on the stud, turn the nut, make the bottom surface of the nut abut against the top surface of the fixing plate 2, and fix the arc plate 1 on the round tube; 3. Fix several round rods on the side of the filter away from the blocking plate. When the filter filters impurities, the impurities are clamped between adjacent round rods, which makes it easier to remove the filter from the pipe and reduces the possibility of impurities falling into the pipe, making it easier to clean the impurities. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the overall structure of a small-diameter differential pressure flowmeter for narrow spaces according to an embodiment of the present application.

[0026] Figure 2 It is a cross-sectional view of the shell in the embodiment of the present application.

[0027] Figure 3 It is a cross-sectional view of the connecting member in the embodiment of the present application.

[0028] Figure 4 It is a schematic diagram of the structure of the pipe fitting in the embodiment of the present application.

[0029] Figure 5 It is a schematic diagram of the structure of the sealing ring in the embodiment of the present application.

[0030] Figure 6 It is a schematic diagram of the structure of the arc plate 2 in the embodiment of the present application.

[0031] 1. Shell; 11. Delivery pipe; 12. Connecting pipe; 13. Flow meter; 14. Connecting rod; 2. Connecting piece; 21. Through port; 22. Mounting groove; 23. Sealing plate; 24. Through hole; 25. Moving rod; 26. Driving pipe; 3. Mounting box; 31. Bevel gear one; 32. Rotating shaft; 33. Bevel gear two; 34. Rotating block; 35. Scale line; 36. Indicator needle; 4. Pipe fitting; 41. Annular groove one; 42. Filter screen; 43. Round rod; 44. Through groove; 45. Arc plate one; 46. Annular groove two; 5. Annular groove three; 51. Sealing ring; 52. Annular groove four; 53. Fixed block one; 54. Fixed block two; 55. Round hole; 56. Stud; 57. Nut; 58. Arc plate two. DETAILED DESCRIPTION

[0032] The following is combined with Figure 1-6 This application is described in further detail.

[0033] The embodiment of the present application discloses a small-diameter differential pressure flow meter for use in a narrow space.

[0034] Reference Figure 1 and Figure 2 A small-diameter differential pressure flowmeter for a narrow space includes a housing 1, a delivery pipe 11 is arranged in the housing 1, and connecting pipes 12 are fixed at both ends of the delivery pipe 11. The connecting pipe 12 is a tapered pipe, and the outer periphery of the connecting pipe 12 is fixedly connected to the inner periphery of the housing 1.

[0035] Reference Figure 2 and Figure 3 , connectors 2 are fixed at both ends of the housing 1, a through hole 21 is opened on the side of the connector 2, the through hole 21 is connected to the connecting pipe 12, and a pipe fitting 4 is fixed on the end face of the connector 2 away from the connecting pipe 12. A flow meter 13 is arranged above the housing 1, and connecting rods 14 are fixed on both sides of the bottom surface of the flow meter 13, and the bottom end of the connecting rod 14 passes through the housing 1 and is inserted into the delivery pipe 11.

[0036] Reference Figure 2 and Figure 3 The inner circumference of the through hole 21 is provided with a mounting groove 22, a blocking plate 23 is vertically slidably arranged in the mounting groove 22, a through hole 24 is provided in the inner top surface of the mounting groove 22, a moving rod 25 is fixed to the top surface of the blocking plate 23, and the top end of the moving rod 25 passes through the through hole 24. A driving tube 26 is rotatably mounted on the outer circumference of the connecting member 2, the top end of the moving rod 25 is inserted into the driving tube 26, and the driving tube 26 is threadedly connected to the moving rod 25.

[0037] Reference Figure 2 and Figure 3 The outer circumferential surface of the connecting member 2 is fixed with the installation box 3, and the driving tube 26 is located in the installation box 3. The top of the driving tube 26 is sleeved with a bevel gear 1 31, and a rotating shaft 32 is penetrated on the side of the installation box 3 away from the flow meter 13. The rotating shaft 32 is rotatably connected with the installation box 3. The end of the rotating shaft 32 close to the driving tube 26 is sleeved with a bevel gear 2 33, and the bevel gear 1 31 is meshed with the bevel gear 2 33. A rotating block 34 is fixed on the end of the rotating shaft 32 away from the installation box 3. A plurality of scale lines 35 are fixed on the side of the installation box 3 close to the rotating block 34, and the plurality of scale lines 35 are arranged at equal intervals along the circumference of the rotating shaft 32. An indicating needle 36 is fixed on the side of the rotating block 34 close to the installation box 3.

[0038] When it is necessary to adjust the water flow in the delivery pipe 11, the rotating block 34 is rotated, the rotating block 34 drives the rotating shaft 32 to rotate, the rotating shaft 32 drives the bevel gear 2 33 to rotate, the bevel gear 2 33 drives the bevel gear 1 31 to rotate, the bevel gear 1 31 drives the driving pipe 26 to rotate, the driving pipe 26 drives the moving rod 25 to move vertically, and the moving rod 25 drives the sealing plate 23 to move vertically to adjust the size of the opening 21, thereby facilitating the adjustment of the water flow in the delivery pipe 11.

[0039] Reference Figure 2 and Figure 4The inner circumference of the pipe 4 is provided with an annular groove 1 41, in which a filter screen 42 is inserted, and a plurality of round rods 43 are fixed on the side of the filter screen 42 away from the connecting pipe 12. The outer circumference of the pipe 4 is provided with a through groove 44, which is connected with the annular groove 1 41. An arc plate 1 45 is arranged in the through groove 44, and the outer side surface of the arc plate 1 45 is in contact with the inner side surface of the through groove 44, and the arc plate 1 45 is used to block the through groove 44. The inner circumference of the arc plate 1 45 is provided with an annular groove 2 46, and the edge of the upper half of the filter screen 42 is inserted in the annular groove 2 46.

[0040] Reference Figure 4 , Figure 5 and Figure 6 , an arc plate 2 58 is fixed to the outer circumference of the arc plate 1 45, and the inner circumference of the arc plate 2 58 is in contact with the outer circumference of the pipe fitting 4. An annular groove 3 5 is provided on the outer circumference of the pipe fitting 4, and the annular groove 3 5 is located on the circumferential side of the through groove 44, and a sealing ring 51 is fixed in the annular groove 3 5. An annular groove 4 52 is provided on the inner circumference of the arc plate 2 58, and the top of the sealing ring 51 is inserted in the annular groove 4 52. Two fixing blocks 1 53 are fixed to the outer circumference of the pipe fitting 4, and studs 56 are fixed to the top surface of the fixing blocks 1 53. Two fixing blocks 2 54 are fixed to the outer circumference of the arc plate 2 58, and the two fixing blocks 2 54 are respectively located at the two ends of the arc plate 1 45, and two circular holes 55 are provided on the top surface of the fixing blocks 2 54, and the circular holes 55 vertically penetrate the fixing blocks 2 54. The top end of the stud 56 passes through the circular hole 55 , and a nut 57 is sleeved on the outer circumference of the stud 56 . The nut 57 is threadedly connected to the stud 56 , and the bottom surface of the nut 57 abuts against the top surface of the fixing block 2 54 .

[0041] The water is filtered by setting the filter screen 42 so that the filtered impurities are clamped between two adjacent round rods 43. When the impurities on the filter screen 42 need to be cleaned, the nut 57 is rotated to disengage the nut 57 from the stud 56, and then the arc plate 2 58 is moved upward. The arc plate 2 58 drives the arc plate 1 45 to move upward, so that the arc plate 2 58 and the arc plate 1 45 are disengaged from the pipe fitting 4, thereby removing the filter screen 42 from the pipe fitting 4 through the through groove 44 to clean the impurities.

[0042] The implementation principle of a small-diameter differential pressure flowmeter for a narrow space in the embodiment of the present application is as follows: when it is necessary to adjust the water flow in the delivery pipe 11, the rotating block 34 is rotated, the rotating block 34 drives the rotating shaft 32 to rotate, the rotating shaft 32 drives the bevel gear 2 33 to rotate, the bevel gear 2 33 drives the bevel gear 1 31 to rotate, the bevel gear 1 31 drives the driving pipe 26 to rotate, the driving pipe 26 drives the moving rod 25 to move vertically, the moving rod 25 drives the blocking plate 23 to move vertically, so that the blocking plate 23 adjusts the size of the opening 21, and then adjusts the water flow in the delivery pipe 11. Since the moving rod 25 and the driving pipe 26 are threadedly connected, the moving rod 25 and the driving pipe 26 have a self-locking function through the thread, so that after the position of the blocking plate 23 is adjusted, there is no need to fix the blocking plate 23 through other fixing mechanisms, so that the blocking plate 23 is relatively simple to fix after adjustment. When the rotating block 34 rotates, the rotating block 34 drives the indicating needle 36 to rotate. When the rotating block 34 stops rotating, the indicating needle 36 points to the scale line 35 installed upward, so that the openings 21 at both ends of the conveying pipe 11 can be adjusted to the same size.

[0043] When water flows into the delivery pipe 11 through the pipe 4, impurities in the water are filtered through the filter 42, reducing the impact of impurities in the water on the use of the flow meter. When the filter 42 is used for a long time and needs to be cleaned, the nut 57 is rotated to disengage the nut 57 from the stud 56, and then the arc plate 2 58 is moved upward, and the arc plate 2 58 drives the arc plate 1 45 to move upward, so that the arc plate 2 58 and the arc plate 1 45 are separated from the pipe 4, thereby removing the filter 42 from the pipe 4 to clean the impurities. Then install the new filter screen 42 in the annular groove 1 41, then align the arc plate 1 45 with the through groove 44, install the arc plate 1 45 in the through groove 44, insert the edge of the upper half of the filter screen 42 into the annular groove 2 46, the inner circumference of the arc plate 2 58 fits the outer circumference of the pipe fitting 4, the top of the sealing ring 51 is inserted into the annular groove 4 52, the top of the stud 56 passes through the circular hole 55, and then the nut 57 is sleeved on the stud 56, and the nut 57 is rotated to make the bottom surface of the nut 57 abut against the top surface of the fixing plate 2, so that the arc plate 1 45 is fixed on the pipe fitting 4, and the connection between the arc plate 2 58 and the pipe fitting 4 is sealed by the sealing ring 51, thereby reducing the possibility of water leakage from the connection between the arc plate 2 58 and the pipe fitting 4.

[0044] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A small-diameter differential pressure flowmeter for a narrow space, comprising a housing (1), a delivery pipe (11) being arranged in the housing (1), a flow meter (13) being arranged on the housing (1), a connecting rod (14) being arranged on the bottom surface of the flow meter (13), the bottom end of the connecting rod (14) passing through the housing (1) and inserted into the delivery pipe (11), connecting pipes (12) being fixed at both ends of the delivery pipe (11), both ends of the housing (1) being fixed to a connecting piece (2), a through opening (21) being provided on the side surface of the connecting piece (2), the through opening (21) being connected to the connecting pipe (12), a pipe fitting (4) being fixed on the end surface of the connecting piece (2) away from the connecting pipe (12), and characterized in that: The inner side surface of the through opening (21) is provided with a mounting groove (22), a blocking plate (23) for adjusting the size of the through opening (21) is vertically slidably arranged in the mounting groove (22), and a driving mechanism for driving the blocking plate (23) to move vertically is arranged on the connecting member (2).

2. A small diameter differential pressure flow meter for narrow space according to claim 1, characterized in that: A through hole (24) is provided on the inner top surface of the mounting groove (22); the driving mechanism comprises a moving rod (25) fixed to the top surface of the blocking plate (23); the top end of the moving rod (25) passes through the through hole (24); a driving tube (26) is rotatably mounted on the top surface of the connecting member (2); the top end of the moving rod (25) is inserted into the driving tube (26); the moving rod (25) is threadedly connected to the driving tube (26); and a driving component for driving the driving tube (26) to rotate is provided on the connecting member (2).

3. A small diameter differential pressure flow meter for narrow space according to claim 2, characterized in that: A mounting box (3) is fixed on the top surface of the connecting member (2), the driving tube (26) is located in the mounting box (3), the driving assembly comprises a bevel gear 1 (31) arranged on the driving tube (26), a rotating shaft (32) is passed through the side of the mounting box (3), the rotating shaft (32) is rotatably connected to the mounting box (3), a bevel gear 2 (33) is arranged at one end of the rotating shaft (32) close to the bevel gear 1 (31), the bevel gear 1 (31) is meshed with the bevel gear 2 (33), and a rotating block (34) is fixed at one end of the rotating shaft (32) away from the mounting box (3).

4. A small diameter differential pressure flow meter for narrow space according to claim 3, characterized in that: A plurality of scale lines (35) are arranged on the side of the installation box (3), and the plurality of scale lines (35) are arranged at equal intervals along the circumference of the rotating shaft (32). An indicating needle (36) is fixed to the side of the rotating block (34) close to the installation box (3).

5. A small diameter differential pressure flow meter for narrow space according to claim 4, characterized in that: The inner circumferential surface of the pipe (4) is provided with an annular groove (41), and a filter screen (42) is arranged in the annular groove (41).

6. A small diameter differential pressure flow meter for narrow space according to claim 5, characterized in that: The outer circumferential surface of the pipe (4) is provided with a through groove (44), an arc-shaped plate (45) is arranged in the through groove (44), the arc-shaped plate (45) is arranged in the through groove (44), an annular groove (46) is provided on the inner circumferential surface of the arc-shaped plate (45), the upper edge of the filter screen (42) is inserted in the annular groove (46), and a fixing piece for fixing with the arc-shaped plate (45) is arranged on the pipe (4).

7. A small diameter differential pressure flow meter for narrow space according to claim 6, characterized in that: The fixing member comprises two fixing blocks (53) fixed on the outer circumference of the pipe (4), a stud (56) being fixed on the top surface of the fixing block (53), an arc plate (58) being fixed on the outer circumference of the arc plate (45), two fixing blocks (54) being fixed on the outer circumference of the arc plate (58), the two fixing blocks (54) being respectively located at two ends of the arc plate (58), a circular hole (55) being opened on the top surface of the fixing block (54), the top end of the stud (56) passing through the circular hole (55), a nut (57) being sleeved on the stud (56), the nut (57) being threadedly connected to the stud (56), the bottom surface of the nut (57) being in contact with the top surface of the fixing block (54).

8. A small diameter differential pressure flow meter for narrow space according to claim 7, characterized in that: The inner circumference of the second arc plate (58) is in contact with the outer circumference of the pipe fitting (4); the outer circumference of the pipe fitting (4) is provided with an annular groove (5); the annular groove (5) is located on the circumferential side of the through groove (44); the inner circumference of the second arc plate (58) is provided with an annular groove (52); a sealing ring (51) is fixed in the annular groove (5), and the top end of the sealing ring (51) is inserted in the annular groove (52).

9. A small diameter differential pressure flow meter for narrow space according to claim 5, characterized in that: A plurality of round rods (43) are fixed to the side of the filter screen (42) away from the blocking plate (23).

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