Double-screw flowmeter

Abstract

The utility model belongs to the technical field of measuring instruments, and particularly relates to a double-screw flowmeter which comprises a shell, a cavity is arranged in the shell, an inlet end and an outlet end are arranged at the two ends of the cavity respectively, an inlet fixing plate is arranged at the inlet end, a positioning seat is arranged at the outlet end, and an outlet fixing plate is arranged between the inlet fixing plate and the outlet fixing plate. The positioning seat is clamped with the outlet fixing plate; the double-screw assembly is located in the cavity and comprises a driving screw and a driven screw which are arranged side by side and meshed with each other, the two ends of the driving screw are rotationally connected to the inlet fixing plate and the positioning seat respectively, and the two ends of the driven screw are rotationally connected to the inlet fixing plate and the outlet fixing plate respectively; the magnetic assembly is arranged on the driving screw in a sleeving manner; and the detection assembly is arranged on the shell and at least comprises an inductor corresponding to the magnetic assembly. The structure is simple, the assembly process is simplified, the number of assembly parts is reduced, assembly procedures are reduced, and the whole structure is small, compact and light.

Description

Technical Field

[0001] The utility model belongs to the technical field of measuring instruments, in particular to a twin-screw flow meter. Background Art

[0002] Flowmeter is an instrument used to indicate the flow rate of the measured medium and the total amount of fluid in a selected time interval. It is usually used to measure the flow rate of fluid medium transported in pipelines or open channels. There are many types of flowmeters. Among them, the volumetric flowmeter has high measurement accuracy and high cost performance. As a type of volumetric flowmeter, the twin-screw flowmeter has been widely used in many fields due to its high accuracy, fast response speed and ability to measure small flow rates of high-viscosity fluid media.

[0003] However, existing twin-screw flow meters often have complex structures and a large number of parts, which leads to cumbersome assembly processes, large overall size, high cost, and are not suitable for scenarios in small spaces. Utility Model Content

[0004] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide a twin-screw flowmeter for solving the technical problems of the twin-screw flowmeter in the prior art in that the assembly structure is complex and the assembly process is cumbersome.

[0005] In order to achieve the above-mentioned purpose and other related purposes, the technical solution of the utility model is as follows:

[0006] A twin-screw flow meter, comprising:

[0007] The shell has a cavity inside, the two ends of the cavity are respectively an inlet end and an outlet end, the inlet end is provided with an inlet fixing plate, the outlet end is provided with a positioning seat, an outlet fixing plate is provided between the inlet fixing plate and the outlet fixing plate, and the positioning seat is clamped with the outlet fixing plate;

[0008] A twin screw assembly is located in the cavity, and includes a pair of active screws and driven screws arranged side by side and meshing with each other, wherein two ends of the active screw are rotatably connected to the inlet fixing plate and the positioning seat respectively, and two ends of the driven screw are rotatably connected to the inlet fixing plate and the outlet fixing plate respectively;

[0009] A magnetic component is sleeved on the active screw; and

[0010] The detection component is arranged on the housing and at least comprises a sensor arranged corresponding to the magnetic component.

[0011] Optionally, a cavity anti-rotation structure is provided inside the cavity near the inlet end and the outlet end, and the inlet fixing plate and the outlet fixing plate are both provided with a fixing plate anti-rotation structure adapted to the corresponding cavity anti-rotation structure.

[0012] Optionally, the cavity anti-rotation structure includes a cavity anti-rotation portion abutting against the inner wall of the cavity, a cavity through hole is opened on the cavity anti-rotation portion, and the cavity through hole is in an 8-shaped structure. The cavity anti-rotation portion is provided with cavity notches on both sides of the cavity through hole, and the cavity notches are connected to the cavity through hole.

[0013] Optionally, the fixed plate anti-rotation structure includes a plate body and a boss portion protruding from the plate body, the boss portion is in an 8-shaped structure, and fixed plate notches are relatively arranged on both sides of the plate body at the boss portion, and the fixed plate notches are correspondingly connected to the cavity notches, the boss portion is adapted to the cavity through hole, and there is a gap between the boss portion and the cavity notch.

[0014] Optionally, the positioning seat includes a positioning body and two extension parts extending toward the outlet fixed plate, the two extension parts are arranged opposite to each other and are clamped in the notch of the fixed plate, and a liquid-passing notch is provided on the positioning body, and the liquid-passing notch is connected to the notch of the fixed plate.

[0015] Optionally, both ends of the active screw rod are axially abutted against the inlet fixing plate and the positioning seat via limiting balls, and both ends of the driven screw rod are axially abutted against the inlet fixing plate and the outlet fixing plate via limiting balls.

[0016] Optionally, the active screw and the driven screw are both sleeved with shaft sleeves, and are rotatably connected to the inlet fixing plate and the outlet fixing plate respectively through the shaft sleeves.

[0017] Optionally, the magnetic component includes a disk body, a magnet and a magnetic shell, the magnetic shell is covered outside the disk body, a plurality of mounting holes are opened on the disk body along its circumferential side wall, a magnet is arranged in each mounting hole, and the magnetic poles of adjacent magnets are arranged alternately.

[0018] Optionally, it also includes an inlet end cover and an outlet end cover, the inlet end cover is arranged at the inlet end of the cavity and presses the inlet fixing plate, the outlet end cover is arranged at the outlet end of the cavity and presses the positioning seat, and the inlet end cover and the outlet end cover are both provided with joint holes; sealing members are both provided between the inlet end cover and the inlet end, and between the outlet end cover and the outlet end.

[0019] Optionally, the detection component further includes a junction box, a main detection board and a sub-detection board which are arranged in the junction box and electrically connected to each other, and the sensor is mounted on the sub-detection board.

[0020] As described above, the twin-screw flowmeter of the utility model has the following beneficial effects:

[0021] By arranging the inlet fixing plate and the positioning seat at the inlet end and the outlet end of the cavity, and arranging the outlet fixing plate and the positioning seat for clamping connection, the rotation connection and positioning of the twin-screw assembly can be realized through the cooperation of the inlet fixing plate, the outlet fixing plate and the positioning seat. The structure is simple, the assembly process is simplified, the number of assembly parts is reduced, the assembly process is reduced, and the overall structure is small, compact and lightweight, which is suitable for application in small flow dispensing occasions. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the external structure of a twin-screw flowmeter according to an embodiment of the utility model;

[0023] Figure 2 A cross-sectional view of a twin-screw flowmeter according to an embodiment of the present utility model;

[0024] Figure 3 A partial internal structure diagram of a twin-screw flowmeter according to an embodiment of the present utility model;

[0025] Figure 4 for Figure 3 A cross-sectional view of

[0026] Figure 5 The structure of the housing of the utility model is shown in FIG. Figure 1 (entrance end);

[0027] Figure 6 The structure of the housing of the utility model is shown in FIG. Figure 2 (Export end);

[0028] Figure 7 A cross-sectional view of a housing of an embodiment of the utility model;

[0029] Figure 8 A side view of a housing according to an embodiment of the present utility model;

[0030] Fig. 9 It is a schematic diagram of the assembly of the inlet fixing plate and the housing of an embodiment of the utility model;

[0031] Fig.10 It is a schematic diagram of the assembly of the outlet fixing plate and the housing of an embodiment of the utility model;

[0032] Fig.11 This is a schematic structural diagram of an inlet fixing plate according to an embodiment of the utility model;

[0033] Fig.12 This is a schematic structural diagram of an outlet fixing plate according to an embodiment of the utility model;

[0034] Fig.13 It is a structural schematic diagram of a positioning seat according to an embodiment of the utility model.

[0035] Description of Reference Numerals

[0036] 10-housing; 11-cavity; 12-cavity anti-rotation part; 121-cavity through hole; 122-cavity notch;

[0037] 21-inlet fixing plate; 211-first accommodating hole; 22-outlet fixing plate; 221-second accommodating hole; 222-positioning hole; 201-plate body; 202-boss; 203-fixing plate notch;

[0038] 23-positioning seat; 231-positioning body; 232-extension portion; 233-liquid notch; 234-third accommodating hole;

[0039] 30-twin screw assembly; 31-active screw; 32-driven screw; 33-limiting ball; 34-shaft sleeve;

[0040] 40-magnetic component; 41-disk body; 42-magnetic steel; 43-magnetic shell;

[0041] 50-detection component; 51-junction box; 52-main detection board; 53-secondary detection board; 54-sensor;

[0042] 60-inlet end cover; 61-connector hole;

[0043] 70- outlet end cover; 71- connector hole;

[0044] 80-Seal. DETAILED DESCRIPTION

[0045] The following is a specific embodiment of the present invention. People familiar with the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. The details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0046] It should be noted that the diagrams provided in the present embodiment are only used to illustrate the basic concept of the present invention in a schematic manner, so the diagrams only show the components related to the present invention rather than being drawn according to the number, shape and size of the components in actual implementation. The form, quantity and proportion of each component in actual implementation can be changed at will, and the layout of the components may also be more complicated. It should be noted that the structure, proportion, size, etc. shown in the drawings attached to this specification are only used to match the content disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions that the present invention can be implemented, so they have no technical substantive significance. Any modification of the structure, change in the proportional relationship or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the effect and purpose that the present invention can produce. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" cited in this specification are only for the convenience of description and are not used to limit the scope of the implementation of the present utility model. Changes or adjustments to their relative relationships should be regarded as the scope of the implementation of the present utility model without substantially changing the technical content.

[0047] In order to describe the utility model in detail, the twin-screw flowmeter of the utility model is specifically described below:

[0048] Please combine Figures 1 to 4 As shown, the utility model provides a twin-screw flowmeter, including: a housing 10, a twin-screw assembly 30, a magnetic assembly 40 and a detection assembly 50, wherein the housing 10 has a cavity 11 inside, the two ends of the cavity 11 are respectively an inlet end and an outlet end, the inlet end is provided with an inlet fixing plate 21, the outlet end is provided with a positioning seat 23, an outlet fixing plate 22 is provided between the inlet fixing plate 21 and the outlet fixing plate 22, and the positioning seat 23 is clamped with the outlet fixing plate 22; the twin-screw assembly 30 is located in the cavity 11, including A pair of active screw 31 and driven screw 32 are arranged side by side and meshed with each other, the two ends of the active screw 31 are respectively rotatably connected to the inlet fixing plate 21 and the positioning seat 23, and the two ends of the driven screw 32 are respectively rotatably connected to the inlet fixing plate 21 and the outlet fixing plate 22; the magnetic component 40 is sleeved on the active screw 31; the detection component 50 is arranged on the housing 10, and at least includes a sensor 54 corresponding to the magnetic component 40, so as to convert the rotation angle signal of the magnetic component 40 into a pulse signal.

[0049] Specifically, the housing 10 is a cylindrical one-piece structure, and an inlet fixing plate 21, an outlet fixing plate 22 and a positioning seat 23 are sequentially arranged from the inlet end to the outlet end of the cavity 11 along the medium flow direction, wherein the inlet fixing plate 21 and the outlet fixing plate 22 are clamped on the cavity 11, and the positioning seat 23 is clamped with the outlet fixing plate 22, so that the position stability of the inlet fixing plate 21, the outlet fixing plate 22 and the positioning seat 23 in the cavity 11 can be ensured (without relying on additional fasteners for connection). The active screw 31 and the driven screw 32 are arranged in parallel and mesh with each other, and the total length of the active screw 31 is greater than the total length of the driven screw 32; the first end of the active screw 31 is rotatably connected to the inlet fixing plate 21, and the second end of the active screw 31 passes through the outlet fixing plate 22 and is rotatably connected to the positioning seat 23; the first end of the driven screw 32 is rotatably connected to the inlet fixing plate 21, and the second end of the driven screw 32 is rotatably connected to the outlet fixing plate 22. In this way, the cooperation of the inlet fixing plate, the outlet fixing plate 22 and the positioning seat 23 is conducive to quickly realizing the rotational connection and positioning of the twin-screw assembly 30. The overall structure is simple, which simplifies the assembly process, reduces the number of assembly parts, reduces the assembly process, and helps to make the overall structure small, lightweight, and more compact.

[0050] In some embodiments, the cavity 11 is provided with a cavity anti-rotation structure near the inlet end and the outlet end, and the inlet fixed plate 21 and the outlet fixed plate 22 are provided with a fixed plate anti-rotation structure adapted to the corresponding cavity anti-rotation structure. Specifically, the cavity 11 is divided into a first cavity and a second cavity connected to each other along the flow direction of the medium, and the inner diameter of the second cavity is larger than the inner diameter of the first cavity; the inlet fixed plate 21 is provided at the inlet end of the first cavity, and the outlet fixed plate 22 is provided at the outlet end of the first cavity, and the cavity anti-rotation structure is located at the inlet end and the outlet end of the first cavity. Through the cooperation of the cavity anti-rotation structure and the fixed plate anti-rotation structure, the anti-rotation connection between the inlet fixed plate 21 and the cavity 11 and the anti-rotation connection between the outlet fixed plate 22 and the cavity 11 can be achieved, thereby ensuring the anti-rotation property of the connection between the inlet fixed plate 21 and the outlet fixed plate 22 and the cavity 11, and further ensuring the installation reliability of the active screw 31 and the driven screw 32.

[0051] See also Figures 5 to 8 In the above embodiment, the cavity anti-rotation structure includes a cavity anti-rotation portion 12 abutting against the inner wall of the cavity 11, and a cavity through hole 121 is opened on the cavity anti-rotation portion 12, and the cavity through hole 121 is in an 8-shaped structure (see Figure 8), cavity notches 122 are arranged on both sides of the cavity through hole 121 on the cavity anti-rotation portion 12, and the cavity notches 122 are connected with the cavity through hole 121. Specifically, the cavity anti-rotation portion 12 extends from the inlet end of the first cavity to the outlet end of the first cavity, the cavity through hole 121 axially penetrates the cavity anti-rotation portion 12, and the cavity through hole 121 is connected with the second cavity; the cavity through hole 121 is in an 8-shaped structure, which is convenient for accommodating the active screw 31 and the driven screw 32, and the cavity notch 122 is connected with the cavity through hole 121, which is convenient for the fluid medium to flow in the cavity 11.

[0052] See also Figures 9 to 12 In the above embodiment, the fixed plate anti-rotation structure includes a plate body 201 and a boss 202 protruding from the plate body 201, the boss 202 is in an 8-shaped structure, the plate body 201 is provided with fixed plate notches 203 on both sides of the boss 202, and the fixed plate notches 203 are correspondingly connected with the cavity notches 122, the boss 202 is adapted to the cavity through hole 121, and there is a gap between the boss 202 and the cavity notch 122. Specifically, the boss 202 is in an 8-shaped structure, which is conducive to adapting to the 8-shaped structure of the cavity through hole 121, thereby playing an anti-rotation role; the fixed plate notch 203 is connected with the cavity notch 122, and there is a gap between the boss 202 and the cavity notch 122, which is conducive to the fluid medium to communicate between the fixed plate notch 203, the cavity notch 122, and the cavity through hole 121. The boss portion 202 of the inlet fixing plate 21 is adapted to the inlet end of the cavity through hole 121 , and the boss portion 202 of the outlet fixing plate 22 is adapted to the outlet end of the cavity through hole 121 .

[0053] See also Fig.13 In the above embodiment, the positioning seat 23 includes a positioning body 231 and two extensions 232 extending toward the outlet fixed plate 22. The two extensions 232 are arranged opposite to each other and are clamped in the fixed plate notch 203. The positioning body 231 is provided with a liquid-passing notch 233, and the liquid-passing notch 233 is connected with the fixed plate notch 203. Specifically, the connection between the positioning seat 23 and the outlet fixed plate 22 is achieved by the two extensions 232 and the fixed plate notch 203 on the outlet fixed plate 22. In addition, the two oppositely arranged extensions 232 can make way for the magnetic assembly 40 to avoid connection interference. The outer wall of the extension 232 is adapted to the inner wall of the second cavity of the cavity 11. The liquid-passing notch 233 corresponds to the driven screw 32. The liquid-passing notch 233 is connected with the fixed plate notch 203 on the outlet fixed plate 22, which is conducive to the fluid medium being connected between the fixed plate notch 203 and the liquid-passing notch 233.

[0054] See also Figure 4It can be understood that both ends of the active screw 31 are axially abutted against the inlet fixing plate 21 and the positioning seat 23 through the limiting balls 33, and both ends of the driven screw 32 are axially abutted against the inlet fixing plate 21 and the outlet fixing plate 22 through the limiting balls 33. Specifically, two first accommodating holes 211 for accommodating limiting balls 33 are provided on the side of the inlet fixing plate 21 facing the inside of the cavity 11, and the first end of the active screw 31 and the first end of the driven screw 32 are axially abutted against the inlet fixing plate 21 through the limiting balls 33; a second accommodating hole 221 for accommodating limiting balls 33 is provided on the side of the outlet fixing plate 22 facing the inlet fixing plate 21, and the second end of the driven screw 32 is axially abutted against the outlet fixing plate 22 through the limiting balls 33; the outlet fixing plate 22 is also provided with an axially through positioning hole 222, and a third accommodating hole 234 for accommodating limiting balls 33 is provided on the positioning seat 23 on the side facing the inside of the cavity 11, and the second end of the active screw 31 passes through the positioning hole 222 and axially abuts against the positioning seat 23 through the limiting balls 33. The limiting ball 33 abuts against the ends of the active screw 31 and the driven screw 32 , thereby facilitating the smoothness of rotation of the active screw 31 and the driven screw 32 .

[0055] Continue reading Figure 4 In the above embodiment, the driving screw 31 and the driven screw 32 are both sleeved with shaft sleeves 34, and are rotatably connected to the inlet fixing plate 21 and the outlet fixing plate 22 respectively through the shaft sleeves 34. Specifically, the two ends of the driving screw 31 are sleeved with shaft sleeves 34, and the two ends of the driven screw 32 are also sleeved with shaft sleeves 34. The driving screw 31 and the driven screw 32 are both rotatably connected to the inlet fixing plate 21 and the outlet fixing plate 22 through the shaft sleeves 34, and cooperate with the limiting balls 33 abutting at the ends, which is beneficial to axial positioning and reduces friction, and ensures the smooth rotation of the driving screw 31 and the driven screw 32.

[0056] See also Figure 4 It should be noted that the magnetic component 40 includes a disk body 41, a magnet 42 and a magnetic shell 43. The magnetic shell 43 is coated on the outside of the disk body 41. The disk body 41 is provided with a plurality of mounting holes along its own circumferential side wall. A magnet 42 is arranged in each mounting hole, and the magnetic poles of adjacent magnets 42 are arranged alternately. Specifically, the magnetic component 40 is arranged at one end of the active screw 31 close to the positioning seat 23. The plurality of mounting holes are evenly distributed on the circumferential side wall of the disk body 41. The magnetic shell 43 covers each mounting hole to protect the magnet 42. The magnetic poles of adjacent magnets 42 are arranged alternately, which is conducive to realizing the detection of the angle change of the magnetic component 40 by the sensor 54 when the magnetic component 40 rotates with the active screw 31. The magnetic component 40 is made of the magnet 42. Since the magnet 42 is strong and durable, has high temperature adaptability, excellent magnetic properties, and strong penetration, it is conducive to improving the detection accuracy of the magnetic component 40.

[0057] See also Figure 2 In the above embodiment, an inlet end cover 60 and an outlet end cover 70 are further included. The inlet end cover 60 is arranged at the inlet end of the cavity 11 and presses the inlet fixing plate 21. The outlet end cover 70 is arranged at the outlet end of the cavity 11 and presses the positioning seat 23. Joint holes are provided on the inlet end cover 60 and the outlet end cover 70. A sealing member 80 is provided between the inlet end cover 60 and the inlet end, and between the outlet end cover 70 and the outlet end. Specifically, the inlet end cover 60 and the outlet end cover 70 can be connected to the housing 10 through fasteners (such as screws). The inlet fixing plate 21 is axially pressed by the inlet end cover 60, and the positioning seat 23 is axially pressed by the outlet end cover 70. The positioning seat 23 then axially presses the outlet fixing plate 22, thereby realizing the axial positioning of the inlet fixing plate 21, the outlet fixing plate 22 and the positioning seat 23. In addition, a joint hole 61 is formed on the inlet end cover 60 and a joint hole 71 is formed on the outlet end cover 70. The joint hole 61 of the inlet end cover 60 is connected to the fixing plate notch 203 on the inlet fixing plate 21, and the joint hole 71 of the outlet end cover 70 is connected to the liquid passing notch 233 on the positioning seat 23.

[0058] Continue reading Figure 2 It can be understood that the detection component 50 also includes a junction box 51, a main detection board 52 and a sub-detection board 53 which are arranged in the junction box 51 and are electrically connected to each other, and the sub-detection board 53 is installed with the sensor 54. Specifically, the junction box 51 is arranged on one side of the housing 10, and the housing 10 is provided with a sensing hole corresponding to the sensor 54. The sensor 54 extends into the sensing hole but does not contact the magnetic component 40. The non-contact detection is achieved through the magnetic induction between the sensor 54 and the magnetic component 40. In addition, a wiring plug is also connected to the junction box 51, and the wiring plug faces the side of the inlet cover 60, and the inlet cover 60 has a yielding surface corresponding to the wiring plug to avoid the wiring plug.

[0059] The twin-screw flowmeter can be used for accurate measurement of the flow of high-viscosity liquid media. Its working principle is to encapsulate the mutually meshing active screw 31 and driven screw 32 in the cavity 11. The liquid medium flows under the impetus of the inlet and outlet pressure difference, thereby driving the active screw 31 and the driven screw 32 to rotate. The sensor 54 performs magnetic induction on the magnetic component 40 to generate a pulse signal to facilitate the measurement output.

[0060] To sum up, the twin-screw flowmeter provided by the utility model is arranged at the inlet end and the outlet end of the cavity 11 through the inlet fixing plate 21 and the positioning seat 23, and the outlet fixing plate 22 is arranged to be clamped with the positioning seat 23. The rotation connection and positioning of the twin-screw assembly 30 can be achieved through the cooperation of the inlet fixing plate 21, the outlet fixing plate 22 and the positioning seat 23. It has a simple structure, simplifies the assembly process, reduces the number of assembly parts, reduces the assembly process, and is conducive to making the overall structure small, lightweight, and more compact, and is suitable for use in small flow dispensing occasions.

[0061] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the technology may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed in the present invention shall still be covered by the claims of the present invention.

Claims

1. A twin-screw flow meter, characterized in that: include: The shell has a cavity inside, the two ends of the cavity are respectively an inlet end and an outlet end, the inlet end is provided with an inlet fixing plate, the outlet end is provided with a positioning seat, an outlet fixing plate is provided between the inlet fixing plate and the outlet fixing plate, and the positioning seat is clamped with the outlet fixing plate; A twin screw assembly is located in the cavity, and includes a pair of active screws and driven screws arranged side by side and meshing with each other, wherein two ends of the active screw are rotatably connected to the inlet fixing plate and the positioning seat respectively, and two ends of the driven screw are rotatably connected to the inlet fixing plate and the outlet fixing plate respectively; A magnetic component, sleeved on the active screw; as well as The detection component is arranged on the housing and at least comprises a sensor arranged corresponding to the magnetic component.

2. The twin-screw flowmeter according to claim 1, characterized in that: The cavity is provided with cavity anti-rotation structures near the inlet end and the outlet end, and the inlet fixing plate and the outlet fixing plate are both provided with fixing plate anti-rotation structures adapted to the corresponding cavity anti-rotation structures.

3. The twin-screw flowmeter according to claim 2, characterized in that: The cavity anti-rotation structure includes a cavity anti-rotation portion abutting against the inner wall of the cavity, a cavity through hole is opened on the cavity anti-rotation portion, and the cavity through hole is in an 8-shaped structure. The cavity anti-rotation portion is provided with cavity notches on both sides of the cavity through hole, and the cavity notches are connected to the cavity through hole.

4. The twin-screw flowmeter according to claim 3, characterized in that: The fixed plate anti-rotation structure includes a plate body and a boss portion protruding from the plate body, the boss portion is in an 8-shaped structure, and fixed plate notches are relatively arranged on both sides of the plate body at the boss portion, and the fixed plate notches are correspondingly connected to the cavity notches, the boss portion is adapted to the cavity through hole, and there is a gap between the boss portion and the cavity notch.

5. The twin-screw flowmeter according to claim 4, characterized in that: The positioning seat includes a positioning body and two extensions extending toward the outlet fixed plate. The two extensions are arranged opposite to each other and are clamped in the notch of the fixed plate. A liquid-excess notch is provided on the positioning body, and the liquid-excess notch is communicated with the notch of the fixed plate.

6. The twin-screw flowmeter according to claim 1, characterized in that: Both ends of the active screw rod are axially abutted against the inlet fixing plate and the positioning seat through limiting balls, and both ends of the driven screw rod are axially abutted against the inlet fixing plate and the outlet fixing plate through limiting balls.

7. The twin-screw flowmeter according to claim 6, characterized in that: The active screw and the driven screw are both sleeved with shaft sleeves, and are rotatably connected to the inlet fixing plate and the outlet fixing plate respectively through the shaft sleeves.

8. The twin-screw flowmeter according to claim 1, characterized in that: The magnetic assembly includes a disk body, a magnet and a magnetic shell. The magnetic shell is covered outside the disk body. The disk body is provided with a plurality of mounting holes along its circumferential side wall. A magnet is arranged in each mounting hole, and the magnetic poles of adjacent magnets are arranged alternately.

9. The twin-screw flowmeter according to claim 1, characterized in that: It also includes an inlet end cover and an outlet end cover, wherein the inlet end cover is arranged at the inlet end of the cavity and presses the inlet fixing plate, and the outlet end cover is arranged at the outlet end of the cavity and presses the positioning seat, and joint holes are provided on the inlet end cover and the outlet end cover; sealing members are provided between the inlet end cover and the inlet end, and between the outlet end cover and the outlet end.

10. The twin-screw flowmeter according to claim 1, characterized in that: The detection assembly further comprises a junction box, a main detection board and a secondary detection board which are arranged in the junction box and are electrically connected to each other, and the sensor is mounted on the secondary detection board.

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