Piston type dynamic flowmeter with magnetic guide rail structure

Abstract

The invention provides a piston type dynamic flowmeter of a magnetic guide rail structure, which comprises a cylinder body, a piston capable of reciprocating along the axial direction is arranged in the cylinder body, and the piston is connected with a driving structure used for driving the piston to rotate along the circumferential direction while reciprocating along the axial direction; the driving structure comprises at least one cylinder body magnetic guide rail with magnetism and at least one piston magnetic guide rail with magnetism, and when the piston moves in the axial direction, the piston magnetic guide rail is separated from the corresponding cylinder body magnetic guide rail, so that magnetic attraction force is formed between the curved surface of the piston magnetic guide rail and the corresponding cylinder body magnetic guide rail. The magnetic attraction force can force the piston to synchronously rotate in the circumferential direction when the piston moves in the axial direction; due to the fact that the piston is driven by magnetic force to rotate, friction pairs are reduced, metering errors caused by friction and abrasion are avoided, and accuracy and long-term stability of the flowmeter are improved.

Description

Technical Field

[0001] This invention relates to the field of flow meter technology, and in particular to a piston-type dynamic flow meter with a magnetic guide rail structure. Background Technology

[0002] Unlike conventional piston flow meters, the two-dimensional piston flow meter has a piston with two degrees of freedom: rotation and linear motion. It features a rolling friction pair consisting of a cam guide and rollers. When the measured oil pushes the piston in a linear motion, the piston can also rotate under the combined action of the cam guide and rollers. The linear motion is responsible for measuring the oil, while the rotation changes the communication area between the grooves on the piston surface and the windows on the cylinder, thus creating a flow distribution function.

[0003] However, the cam guide rail and the roller experience rolling friction. After long-term operation, friction and wear will occur on the contour surface of the cam guide rail and the surface of the roller, which will affect the piston operation and thus affect the working accuracy and service life of the flow meter.

[0004] Therefore, the above-mentioned prior art has at least the following technical problems: the two-dimensional piston flow meter in the prior art uses a cam guide rail and a roller to drive the piston to rotate. After long-term operation, wear will occur, affecting the piston operation, which will lead to a decrease in the flow meter's measurement accuracy and service life. Summary of the Invention

[0005] This application provides a piston-type dynamic flow meter with a magnetic guide rail structure, which solves the problem in the prior art where two-dimensional piston flow meters use a cam guide rail and roller to drive the piston to rotate. After long-term operation, wear will occur, affecting the piston's operation and thus leading to a decrease in the flow meter's measurement accuracy and service life.

[0006] To solve the above technical problems, this application provides a piston-type dynamic flow meter with a magnetic guide rail structure. The flow meter includes a cylinder. The axial direction is defined as the direction along or parallel to the central axis of the cylinder. The radial direction is the direction in which the diameter of the cross-section of the cylinder is located. The circumferential direction is the direction around the axial direction.

[0007] The cylinder body is provided with a piston that can reciprocate along the axial direction, and the piston is connected to a drive structure for driving the piston to reciprocate along the axial direction and rotate along the circumferential direction at the same time.

[0008] The driving structure comprises cylinder magnetic force assemblies symmetrically arranged on the left and right ends of the cylinder with respect to the cross section of the cylinder and piston magnetic force assemblies symmetrically arranged on the left and right ends of the piston with respect to the cross section of the piston, the cylinder magnetic force assembly comprises at least one cylinder magnetic force guide rail with magnetism, the piston magnetic force assembly comprises at least one piston magnetic force guide rail with magnetism, the piston magnetic force guide rail and the cylinder magnetic force guide rail both extend along the circumferential direction and correspond to each other along the radial direction, and the polarities of the corresponding cylinder magnetic force guide rail and the piston magnetic force guide rail are opposite.

[0009] The piston magnetic force guide rail is an axial annular curved surface, the curved surface undulates uniformly along the axial direction, the projection of the curved surface in the direction of the central axis is a circular ring, the curved surface has two highest points and two lowest points, the highest points and the lowest points are located on two mutually perpendicular diameters of the circular ring respectively, and the curved surface is symmetrical with respect to the two diameters.

[0010] The cylinder magnetic force guide rail comprises a pair of cylinder guide rail bodies symmetrically arranged on the cylinder, and each cylinder guide rail body is in the shape of an arc extending along the circumferential direction, and the central angle of the cylinder guide rail body along the circumferential direction is not greater than 90°.

[0011] When the piston moves along the axial direction, the piston magnetic force guide rail is separated from the corresponding cylinder magnetic force guide rail, so that the curved surface of the piston magnetic force guide rail and the corresponding cylinder magnetic force guide rail form a magnetic attraction force, which forces the piston to rotate along the circumferential direction while moving along the axial direction.

[0012] The piston divides the cylinder into a left volume cavity and a right volume cavity, the cylinder is provided with a liquid inlet channel and a liquid outlet channel respectively, and the left volume cavity and the right volume cavity are alternately connected to the liquid inlet channel and the liquid outlet channel in the process of reciprocating movement along the axial direction and rotation along the circumferential direction, so that the left volume cavity and the right volume cavity alternately take in liquid and discharge liquid to measure the volume of liquid.

[0013] Further, the central angle of each cylinder guide rail body is 90°, which is the same as the central angle between the adjacent highest points and the lowest points.

[0014] Further, the spacing between any two adjacent piston magnetic force guide rails and / or any two adjacent cylinder magnetic force guide rails is the same.

[0015] Further, the two ends of the cylinder are respectively provided with a pair of magnetic ring fixing grooves, the pair of magnetic ring fixing grooves are symmetrically arranged on the cylinder, the cylinder magnetic force assembly is fixed on the magnetic ring fixing groove, and the piston magnetic force guide rail is coaxially fixed on the piston.

[0016] Further, the magnetic ring fixing groove is in the shape of a frame, and the cylinder guide rail body is clamped into the frame for fixation.

[0017] Further, the cylinder magnetic assembly comprises three cylinder magnetic guide rails, and the three cylinder magnetic guide rails are respectively N-pole, S-pole and N-pole along the radial direction inwardly.

[0018] The piston magnetic assembly comprises three piston magnetic guide rails, and the three piston magnetic guide rails are respectively S-pole, N-pole and S-pole along the radial direction outwardly.

[0019] Further, the cylinder magnetic assembly comprises three cylinder magnetic guide rails, and the three cylinder magnetic guide rails are respectively N-pole, S-pole and N-pole along the radial direction inwardly.

[0020] The piston magnetic assembly comprises three piston magnetic guide rails, and only the middle one of the three piston magnetic guide rails has magnetism, and the middle one is N-pole along the radial direction outwardly.

[0021] Further, the cylinder magnetic assembly comprises three cylinder magnetic guide rails, and only the middle one of the three cylinder magnetic guide rails has magnetism, and the middle one is N-pole along the radial direction inwardly.

[0022] The piston magnetic assembly comprises three annular piston magnetic guide rails, and only the middle one of the three piston magnetic guide rails has magnetism, and the middle one is S-pole along the radial direction outwardly.

[0023] Further, the piston is provided with a shaft shoulder, and the left and right ends of the cylinder and the piston are provided with two sink sleeves for sealing, and the two sink sleeves and the shaft shoulder form left and right volume cavities in the cylinder respectively.

[0024] Two axially symmetrical left axial grooves and two axially symmetrical right axial grooves are formed on the outer surface of the shaft shoulder of the piston, and the left axial grooves and the right axial grooves are alternately arranged at equal angles along the circumferential direction on the outer surface of the piston, wherein the left axial grooves are in communication with the left volume cavity, and the right axial grooves are in communication with the right volume cavity.

[0025] The left end of the cylinder is provided with a left annular groove, and the wall surface of the left end of the cylinder is further provided with two axially symmetrical left liquid inlet holes, one end of the left liquid inlet hole is in communication with the left annular groove, and the other end is in communication with the left axial groove or the right axial groove.

[0026] The right end of the cylinder is provided with a right annular groove, and the wall surface of the right end of the cylinder is further provided with two axisymmetric right liquid outlet holes, one end of the right liquid outlet hole is communicated with the right annular groove, and the other end is used for being communicated with the left axial groove or the right axial groove;

[0027] The projections of the left liquid inlet hole and the right liquid outlet hole on the cross section of the cylinder are alternately arranged at equal angles along the circumference;

[0028] The left annular groove and the left liquid inlet hole are sequentially communicated to form a liquid inlet channel, and the right annular groove and the right liquid outlet hole are sequentially communicated to form a liquid outlet channel;

[0029] In the process of axial reciprocating movement and axial rotation of the piston, the left volume cavity, the right volume cavity, the left axial groove, the right axial groove, the liquid inlet channel and the liquid outlet channel have the following corresponding relationship:

[0030] In the first state:

[0031] The measured liquid drives the piston to move along the axial direction to the right, and the piston rotates along the circumferential direction under the magnetic force between the cylinder magnetic guide rail and the piston magnetic guide rail; the left axial groove is aligned with the left liquid inlet hole, the right axial groove is aligned with the right liquid outlet hole, the left volume cavity is liquid-in through the left axial groove and the liquid inlet channel, and the right volume cavity is liquid-out through the right axial groove and the liquid outlet channel;

[0032] In the second state:

[0033] The piston is located at the rightmost end of the axial stroke, the left axial groove is not communicated with the left liquid inlet hole and the right liquid outlet hole, the right axial groove is not communicated with the left liquid inlet hole and the right liquid outlet hole, the left volume cavity neither liquid-in nor liquid-out, and the right volume cavity neither liquid-in nor liquid-out;

[0034] In the third state:

[0035] The measured liquid drives the piston to move along the axial direction to the left, and the piston rotates along the circumferential direction under the magnetic force between the cylinder magnetic guide rail and the piston magnetic guide rail; the right axial groove is aligned with the left liquid inlet hole, and the left axial groove is aligned with the right liquid outlet hole; the left volume cavity is liquid-out through the left axial groove and the liquid outlet channel, and the right volume cavity is liquid-in through the right axial groove and the liquid inlet channel;

[0036] In the fourth state:

[0037] The piston is located at the leftmost end of the axial stroke, the left axial groove is not communicated with the left liquid inlet hole and the right liquid outlet hole, the right axial groove is not communicated with the left liquid inlet hole and the right liquid outlet hole, the left volume cavity neither admits liquid nor discharges liquid, and the right volume cavity neither admits liquid nor discharges liquid.

[0038] Further, the flow meter further comprises a linear velocity sensor connected with the piston, and the linear velocity sensor is used for detecting the axial moving speed of the piston to measure the liquid flow based on the axial moving speed and the liquid volume.

[0039] The one or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages:

[0040] (1) The piston type dynamic flow meter with the magnetic guide rail structure disclosed in the present application utilizes the magnetic force acting between the cylinder magnetic guide rail and the piston magnetic guide rail to make the piston rotate circumferentially while moving axially. Since the magnetic force is used to drive the piston to rotate, the friction pair is reduced, the friction and wear in the flow meter are improved, the manufacturing difficulty and cost are reduced, the measurement error caused by friction and wear is avoided, and the accuracy and long-term stability of the flow meter are improved. In addition, for complex working conditions, such as high viscosity and fluid containing particles, the magnetic transmission can make the piston work stably and is not affected by the properties of the fluid, thereby helping to ensure the accuracy of measurement, and effectively solving the problem that the cam guide rail and the roller are used to drive the piston to rotate in the two-dimensional piston flow meter in the prior art, which will cause wear after long-time operation, thereby affecting the operation of the piston and leading to the decrease of the measurement accuracy and service life of the flow meter.

[0041] (2) The present application obtains the measurement of flow by reading the axial moving speed of the piston. Since the obtained moving speed is a continuous signal, instantaneous measurement is realized, the linearity is high, the response frequency is high, the accuracy of dynamic measurement of the flow meter is greatly improved, and the technical problem of poor measurement accuracy of the flow data measured by the volumetric flow meter in the prior art is effectively solved. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 It is a schematic diagram of the overall structure of the piston type flow meter in the embodiments of the present application;

[0043] Figure 2 It is a structure sectional view of the piston type flow meter when the piston moves axially from left to right in an embodiment of the present application;

[0044] Figure 3 It is a partial structure sectional view of the piston when the piston moves axially from left to right in the embodiments of the present application;

[0045] Figure 4The structure sectional view of the piston magnetic guide rail and the cylinder magnetic guide rail after the piston rotates in the embodiment of the present application;

[0046] Figure 5 The structure sectional view when the piston moves axially from right to left in the embodiment of the present application;

[0047] Figure 6 The structure schematic diagram of the cylinder in the embodiment of the present application;

[0048] Figure 7 The structure schematic diagram of the cylinder magnetic assembly in the embodiment of the present application;

[0049] Figure 8 The structure schematic diagram of the piston in the embodiment of the present application;

[0050] Figure 9 The magnetic pole distribution schematic diagram of the cylinder magnetic guide rail and the piston magnetic guide rail in the embodiment of the present application. DETAILED DESCRIPTION

[0051] The embodiment of the present application provides a piston type dynamic flowmeter with a magnetic guide rail structure, and solves the problem that the two-dimensional piston flowmeter in the prior art uses a cam guide rail and a roller to cooperate to drive the piston to rotate, and long-time operation will cause wear to affect the operation of the piston, thereby causing the measurement accuracy and service life of the flowmeter to decrease.

[0052] In order to better understand the above technical solutions, the above technical solutions will be described in detail below in combination with the drawings and specific embodiments.

[0053] One or more embodiments of the present application provide a piston type dynamic flowmeter with a magnetic guide rail structure, which is described below in combination with the drawings.

[0054] As Figure 1 , Figure 2 , Figures 6 to 9As shown, the piston type dynamic flowmeter with the magnetic guide rail structure in the embodiment of the present application comprises a cylinder 11, the axial direction along the central axis of the cylinder 11 or parallel to the central axis of the cylinder 11 is defined as the axial direction, the circumferential direction around the central axis of the cylinder 11 is defined as the circumferential direction, the axial symmetry is defined as the symmetry with the central axis of the cylinder 11, the radial direction is defined as the direction of the diameter of the cross section of the cylinder 11, one end along the axial direction is the left end, the opposite end is the right end, the position close to the center of the cylinder 11 is the inner position, and the position far away from the center of the cylinder 11 is the outer position. The following description is made according to the above reference orientation, and the description will not be repeated. However, it should be noted that the above orientation or position relationship terms are based on the orientation or position relationship shown in the drawings, and are only used for the convenience of describing the present application and simplifying the description, and thus cannot be understood as indicating or implying that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as limiting the embodiment of the present application.

[0055] The cylinder 11 is provided with a piston 23 which can reciprocate along the axial direction, and the piston 23 is connected with a driving structure for driving the piston 23 to rotate along the circumferential direction while reciprocating along the axial direction;

[0056] The driving structure comprises a cylinder magnetic force assembly 15 which is symmetrically arranged at the left and right ends of the cylinder 11 with respect to the cross section of the cylinder 11, and a piston magnetic force assembly 21 which is symmetrically arranged at the left and right ends of the piston 23 with respect to the cross section of the piston 23, the cylinder magnetic force assembly 15 at least comprises one cylinder magnetic force guide rail 151 with magnetism, the piston magnetic force assembly 21 at least comprises one piston magnetic force guide rail 22 with magnetism, the piston magnetic force guide rail 22 and the cylinder magnetic force guide rail 151 both extend along the circumferential direction, and correspond to each other along the radial direction, and the polarities of the corresponding cylinder magnetic force guide rail 151 and the piston magnetic force guide rail 22 are opposite;

[0057] The piston magnetic force guide rail 22 is an axial annular curved surface, the curved surface undulates uniformly along the axial direction, the projection of the curved surface in the central axis direction is a circular ring, the curved surface of the piston magnetic force guide rail 22 has two highest points 221 and two lowest points 222, the highest points 221 and the lowest points 222 are respectively located on two diameters of the circular ring which are perpendicular to each other, and the curved surface is symmetrical with respect to the two diameters;

[0058] The cylinder magnetic force guide rail 151 comprises two cylinder guide rail bodies b which are symmetrically arranged on the cylinder 11, and each cylinder guide rail body b is an arc shape extending along the circumferential direction, and the central angle of the cylinder guide rail body b along the circumferential direction is not greater than 90°, so as not to exceed the area between the adjacent highest points 221 and the lowest points 222;

[0059] When the piston 23 moves along the axial direction, the piston magnetic guide rail 22 is separated from the corresponding cylinder magnetic guide rail 151, so that the curved surface of the piston magnetic guide rail 22 and the corresponding cylinder magnetic guide rail 151 form a magnetic attraction force, which forces the piston 23 to rotate along the circumferential direction while moving along the axial direction.

[0060] The piston 23 divides the cylinder 11 into a left volume cavity D and a right volume cavity I, and the cylinder 11 is respectively provided with a liquid inlet channel and a liquid outlet channel. During the reciprocating movement of the piston 23 along the axial direction and the rotation of the piston 23 along the circumferential direction, the left volume cavity D and the right volume cavity I are alternately connected to the liquid inlet channel and the liquid outlet channel, so that the left volume cavity D and the right volume cavity I alternately receive liquid and discharge liquid to measure the volume of the liquid.

[0061] Specifically, when the piston 23 is stationary, the piston magnetic guide rail 22 and the corresponding cylinder magnetic guide rail 151 are radially opposite, and when the piston 23 moves along the axial direction under the action of hydraulic pressure, the piston magnetic guide rail 22 and the cylinder magnetic guide rail 151 are forced to separate, as shown in Figure 3 、 4 As shown, the curved surface generates an attractive force F 总 , F 总 can be divided into an axial force Fx along the axial direction, a circumferential force Fy along the circumferential direction, and a radial force Fz along the radial direction, wherein the two radial forces Fz cancel each other out, the circumferential force Fy drives the piston 23 to rotate, until the piston magnetic guide rail 22 and the cylinder magnetic guide rail 151 are again radially opposite, and the axial force Fx hinders the movement of the piston 23 along the axial direction.

[0062] Since the piston magnetic guide rail 22 undulates uniformly along the axial direction, the area between the adjacent lowest point 222 and the highest point 221 on any piston magnetic guide rail 22 constitutes a movement interval, and the corresponding central angle of each movement interval is 90°. In each movement interval, the piston 23 realizes one axial movement in one direction.

[0063] During the rotation of the piston magnetic guide rail 22 along the circumferential direction, the direction of the magnetic attraction force between the curved surface and the cylinder magnetic guide rail 151 changes, thereby ensuring that the piston 23 can rotate 90° in the same direction (counterclockwise or clockwise) when moving linearly in one direction (left or right) to the bottom, thereby providing a basis for subsequent distribution.

[0064] As can be seen from the above description, the piston type dynamic flowmeter with the magnetic guide rail structure disclosed in the application utilizes the magnetic force between the cylinder magnetic guide rails 151 and the piston magnetic guide rails 22 to make the piston 23 rotate circumferentially while moving axially. Since the magnetic force is used to drive the rotation of the piston 23, the friction pair is reduced, the friction and wear in the flowmeter are improved, the manufacturing difficulty and cost are reduced, the measurement error caused by friction and wear is avoided, and the accuracy and long-term stability of the flowmeter are improved. In addition, for complex working conditions such as high viscosity and fluid containing particles, the magnetic transmission can make the piston 23 work stably and is not affected by the properties of the fluid, thereby helping to ensure the accuracy of measurement and effectively solving the problem that the two-dimensional piston flowmeter in the prior art uses a cam guide rail and a roller to drive the piston to rotate, which will cause wear after a long time of operation, thereby affecting the operation of the piston and leading to the decrease of the measurement accuracy and service life of the flowmeter.

[0065] In an embodiment of the application, as shown in Figures 1 to 5 , Figure 7 , 9 illustrated, the central angle of each of the cylinder guide rail bodies b is 90°, which is the same as the central angle between the adjacent highest points 221 and the lowest points 222, so as to ensure that a larger magnetic attraction force is generated between the cylinder guide rail bodies b and the piston magnetic guide rails 22.

[0066] Further, as shown in Figures 2 to 5 , Figures 7 to 9 illustrated, the cylinder magnetic guide rails 151 are equally spaced on the cylinder magnetic assembly 15, the piston magnetic guide rails 22 are equally spaced on the piston magnetic assembly 21, and the cylinder magnetic guide rails 151 and the piston magnetic guide rails 22 correspond to each other.

[0067] For example, in an embodiment of the application, the cylinder magnetic assembly 15 includes three cylinder magnetic guide rails 151 spaced along the axial direction, the piston magnetic assembly 21 includes three piston magnetic guide rails 22 spaced along the axial direction, and the cylinder magnetic guide rails 151 and the piston magnetic guide rails 22 are correspondingly arranged along the radial direction. For example, the magnetic pole distribution of the cylinder magnetic guide rails 151 and the piston magnetic guide rails 22 can include the following scenarios:

[0068] (1) As shown in Figure 9 , the three cylinder magnetic guide rails 151 are respectively N-pole, S-pole and N-pole along the radial direction inward, and the three piston magnetic guide rails 22 are respectively S-pole, N-pole and S-pole along the radial direction outward, and each of the cylinder magnetic guide rails 151 forms a magnetic attraction force with a corresponding one of the piston magnetic guide rails 22;

[0069] (2) three said cylinder magnetic guide rail 151 along the radial direction inward respectively N pole, S pole, N pole, three said piston magnetic guide rail 22, only in the middle of said piston magnetic guide rail 22 has magnetic properties, and the middle of said piston magnetic guide rail 22 along the radial direction outward N pole, form magnetic attraction.

[0070] (3) three said cylinder magnetic guide rail 151, only in the middle of said cylinder magnetic guide rail 151 has magnetic properties, and the middle of said cylinder magnetic guide rail 151 along the radial direction inward N pole; three said piston magnetic guide rail 22, only in the middle of said piston magnetic guide rail 22 has magnetic properties, and the middle of said piston magnetic guide rail 22 along the radial direction outward S pole, form magnetic attraction.

[0071] Through the above several described scenarios can be seen, cylinder magnetic guide rail 151 and piston magnetic guide rail 22 can one to one corresponding to form magnetic force adsorption, also can only through one or two corresponding to form magnetic force adsorption, as long as it can drive the piston 23 circumferential rotation.

[0072] It should be noted that the piston magnetic guide rail 22 and the cylinder magnetic guide rail 151 described in the present application have a gap, which should be set according to the magnetic properties of the magnetic guide rail, that is, the magnetic properties of the magnetic guide rail are larger, the gap can be adjusted accordingly, the magnetic properties of the magnetic guide rail are smaller, the gap can be adjusted, as long as the piston 23 can be subjected to magnetic adsorption and rotation, and the piston 23 is not in direct contact with the cylinder 11, so as to avoid wear with related transmission parts during rotation.

[0073] Further, as shown in Figure 6 , the cylinder 11 is provided with a pair of magnetic ring fixing grooves 12 at both ends, the pair of magnetic ring fixing grooves 12 are symmetrically arranged on the cylinder 11, the cylinder magnetic assembly 15 is clamped and fixed on the magnetic ring fixing groove 12, and the piston magnetic guide rail 22 is coaxially fixed on the piston 23.

[0074] Specifically, the magnetic ring fixing groove 12 is in the form of a frame, and the cylinder magnetic assembly 15 further comprises a base body 152, and the cylinder guide rail body b is arranged on the inner surface of the base body 152, wherein the cylinder guide rail body b is clamped into the frame for fixation, that is, the cylinder guide rail body b is fixed by abutting against the inner wall of the frame along the circumferential direction and along the axial direction.

[0075] In an embodiment of the present application, as shown in Figure 2 , 5 , 8, the piston 23 is provided with a shaft shoulder, and the left and right ends of the cylinder 11 and the piston 23 are provided with a sealing sink 3, and the two sink 3 and the shaft shoulder are respectively enclosed to form a left volume cavity D and a right volume cavity I in the cylinder 11.

[0076] Two axis-symmetrical left axial grooves 24 and two axis-symmetrical right axial grooves 25 are formed on the outer surface of the shaft shoulder of the piston 23, and the left axial grooves 24 and the right axial grooves 25 are alternately arranged on the outer surface of the piston 23 along the equiangular direction of the circumference, wherein the left axial grooves 24 are communicated with the left volume cavity D, and the right axial grooves 25 are communicated with the right volume cavity I;

[0077] The left end of the cylinder body 11 is provided with a left annular groove A, and the wall surface of the left end of the cylinder body 11 is further provided with two axis-symmetrical left liquid inlet holes 13, one end of the left liquid inlet hole 13 is communicated with the left annular groove A, and the other end is used for being communicated with the left axial groove 24 or the right axial groove 25;

[0078] The right end of the cylinder body 11 is provided with a right annular groove K, and the wall surface of the right end of the cylinder body 11 is further provided with two axis-symmetrical right liquid outlet holes 14, one end of the right liquid outlet hole 14 is communicated with the right annular groove K, and the other end is used for being communicated with the left axial groove 24 or the right axial groove 25;

[0079] The projections of the left liquid inlet hole 13 and the right liquid outlet hole 14 on the cross section of the cylinder body 11 are alternately arranged along the equiangular direction of the circumference;

[0080] The left annular groove A, the left liquid inlet hole 13 are sequentially communicated to form a liquid inlet channel, and the right annular groove K, the right liquid outlet hole 14 are sequentially communicated to form a liquid outlet channel;

[0081] In the process of axial reciprocating movement and circumferential rotation of the piston 23, the left volume cavity D, the right volume cavity I, the left axial groove 24, the right axial groove 25, the liquid inlet channel and the liquid outlet channel have the following corresponding relationship:

[0082] In the first state:

[0083] The measured liquid drives the piston 23 to move along the axial direction to the right, and the piston 23 rotates along the circumferential direction under the magnetic force action between the cylinder magnetic guide rail 151 and the piston magnetic guide rail 22; the left axial groove 24 is aligned with the left liquid inlet hole 13, the right axial groove 25 is aligned with the right liquid outlet hole 14, the left volume cavity D is filled with liquid through the left axial groove 24 and the liquid inlet channel connected therewith, and the right volume cavity I is drained through the right axial groove 25 and the liquid outlet channel connected therewith;

[0084] In the second state:

[0085] The piston 23 is located at the leftmost end of the axial stroke, the left axial groove 24 is not connected with the left inlet hole 13 and the right outlet hole 14, the right axial groove 25 is not connected with the left inlet hole 13 and the right outlet hole 14, the left volume cavity D neither admits liquid nor discharges liquid, and the right volume cavity I neither admits liquid nor discharges liquid.

[0086] In the third state:

[0087] The measured liquid drives the piston 23 to move leftward along the axial direction, and the piston 23 rotates along the circumferential direction under the magnetic force between the cylinder magnetic guide rail 151 and the piston magnetic guide rail 22; the right axial groove 25 is aligned with the left inlet hole 13, and the left axial groove 24 is aligned with the right outlet hole 14; the left volume cavity D discharges liquid through the left axial groove 24 and the liquid outlet channel connected therewith, and the right volume cavity I admits liquid through the right axial groove 25 and the liquid inlet channel connected therewith.

[0088] In the fourth state:

[0089] The piston 23 is located at the rightmost end of the axial stroke, the left axial groove 24 is not connected with the left inlet hole 13 and the right outlet hole 14, the right axial groove 25 is not connected with the left inlet hole 13 and the right outlet hole 14, the left volume cavity D neither admits liquid nor discharges liquid, and the right volume cavity I neither admits liquid nor discharges liquid.

[0090] As shown in FIG. 1, Figure 2 , 5 In the above embodiment, the left inlet hole 13 and the right outlet hole 14 are arranged obliquely relative to the cylinder 11, which can facilitate the smooth entry and exit of fluid into or out of the left volume cavity D or the right volume cavity I, especially in low-flow or high-viscosity fluid applications, which can help reduce dead zones and vortexes, thereby improving the measurement sensitivity and accuracy of the flowmeter.

[0091] As shown in FIG. 1, Figure 8 In the above embodiment, the left axial groove 24 and the right axial groove 25 are both in the shape of a “U”.

[0092] In the prior art, the Hall element is used in the traditional volumetric flowmeter to generate a pulse to accumulate a standard volume to measure dynamic flow when the piston rotates. Specifically, several magnetic steels are arranged at equal intervals in the circumferential direction on a rotating part (e.g., a piston), and a Hall element is arranged on a fixed part (a housing). The magnetic steels and the Hall element interact to emit a pulse signal. During circumferential rotation of the magnetic steels, the magnetic steels are aligned with the Hall element every certain angle of rotation, and the Hall element emits a voltage pulse signal in response to mark the number of unit volumes of liquid flow, thereby measuring the liquid flow. However, the number of magnetic steels is limited, so that the data measured by the flowmeter is discrete data, and the measurement accuracy is poor.

[0093] Therefore, in some embodiments of the present application, the flowmeter further comprises a linear velocity sensor connected with the piston 23 to detect the axial movement speed of the piston 23. By externally connecting a linear velocity sensor to the piston 23 to read the axial movement speed of the piston 23, and then obtaining the flow rate through the piston 23 when the piston 23 rotates one circle by experimental or calculated method, the measurement of dynamic flow can be converted by reading the axial movement speed of the piston 23.

[0094] Specifically, the flow rate can be calculated based on the axial movement speed of the piston 23 and the effective cross-sectional area of the piston 23, i.e., q = |v|·a, where q is the flow rate, v is the axial movement speed of the piston 23, and a is the effective cross-sectional area of the piston 23 (i.e., the cross-sectional area in contact with the measured liquid). Since the obtained movement speed is a continuous signal, instantaneous measurement is achieved, the linearity is high, the response frequency is high, and the accuracy of dynamic measurement of the flowmeter is greatly improved. The technical problem of the prior art that the flow data measured by the volumetric flowmeter is discrete and the measurement accuracy is poor is effectively solved.

[0095] The working principle of the flowmeter according to the embodiments of the present application is as follows:

[0096] In the present embodiment, the volumes of the left volume chamber D and the right volume chamber I change during the axial movement of the piston 23. When the piston 23 is located at the middle of its axial stroke, the volumes of the left volume chamber D and the right volume chamber I are equal. When the piston 23 is located at the leftmost end of its axial stroke, the volume of the left volume chamber D is at a minimum value (i.e., the minimum volume of the left volume chamber D), and the volume of the right volume chamber I is at a maximum value (i.e., the maximum volume of the right volume chamber I). When the piston 23 is located at the rightmost end of its axial stroke, the volume of the left volume chamber D is at a maximum value (i.e., the maximum volume of the left volume chamber D), and the volume of the right volume chamber I is at a minimum value (i.e., the minimum volume of the right volume chamber I).

[0097] In the embodiment, each motion interval has an intermediate point 223 between the highest point 221 and the lowest point 222. For example, in an embodiment, the corresponding central angle between the highest point 221 and the intermediate point 223 is 45°, and the corresponding central angle between the lowest point 222 and the intermediate point 223 is 45°.

[0098] In the zero position, the piston 23 is in the middle of the axial stroke, the left inlet hole 13 is aligned with the left axial groove 24, the right outlet hole 14 is aligned with the right axial groove 25, the intermediate point 223 of the left end of the piston magnetic guide rail 22 corresponds to the midpoint of the left end of the cylinder guide rail body b, and the intermediate point 223 of the right end of the piston magnetic guide rail 22 corresponds to the midpoint of the right end of the cylinder guide rail body b, as shown in Figure 2 When the high-pressure measured liquid enters the inlet hole 13 and exits the outlet hole 14, the flowmeter in the embodiment has the following working process in one working cycle (0-180°):

[0099] (1) When the piston 23 rotates from 0° to 45°

[0100] At 0°, the piston 23 is in the middle of the axial stroke, the left volume chamber D and the right volume chamber I have the same volume, the left axial groove 24 is completely aligned with the left inlet hole 13, the communication area is maximum, the right axial groove 25 is completely aligned with the right outlet hole 14, the communication area is maximum, the intermediate point 223 of the piston magnetic guide rail 22 corresponds to the midpoint of the cylinder guide rail body b, as shown in Figure 2

[0101] The measured liquid enters the left volume chamber D through the inlet channel and the left axial groove 24 in sequence, and pushes the piston 23 to move along the axial direction to the right end of the axial stroke, and in the process of moving the piston 23 along the axial direction to the right, the piston magnetic guide rail 22 and the cylinder magnetic guide rail 151 are forced to separate, the magnetic attraction between the piston magnetic guide rail 22 and the cylinder magnetic guide rail 151 forces the piston magnetic guide rail 22 to rotate (the rotation direction is counterclockwise as viewed from left to right), and simultaneously drives the piston 23 to rotate, and the piston magnetic guide rail 22 moves from the intermediate point 223 to the highest point 221 corresponding to the midpoint of the corresponding cylinder magnetic guide rail 151.

[0102] In the process of rotating the piston 23 from 0° to 45°, the communication area between the left axial groove 24 and the left inlet hole 13 gradually decreases from the maximum at 0° to zero, and the communication area between the right axial groove 25 and the right outlet hole 14 gradually decreases from the maximum at 0° to zero; the liquid enters the left volume chamber D through the inlet channel and the left axial groove 24 in sequence, so the volume of the left volume chamber D gradually increases to the maximum; under the extrusion of the piston 23, the volume of the right volume chamber I gradually decreases to the minimum, and the liquid in the right volume chamber I is sequentially discharged through the right axial groove 25 and the outlet channel.

[0103] ​(2) When the piston 23 rotates from 45° to 90°

[0104] When the piston 23 is at 45°, the left axial groove 24 and the right oil outlet hole 14 have a communication area of zero, the right axial groove 25 and the left inlet hole 13 have a communication area of zero, the left volume chamber D neither admits liquid nor discharges liquid, and the right volume chamber I neither admits liquid nor discharges liquid.

[0105] At this time, under the action of inertia, the piston 23 continues to rotate to realize the communication between the left axial groove 24 and the right oil outlet hole 14 and the communication between the right axial groove 25 and the left inlet hole 13. The measured liquid enters the right volume chamber I through the liquid inlet channel and the right axial groove 25 in sequence, and pushes the piston 23 to move axially to the left to the middle of the axial stroke. The magnetic attraction between the piston magnetic guide rail 22 and the cylinder magnetic guide rail 151 forces the piston magnetic guide rail 22 to continue to rotate and synchronously drive the piston to rotate. The piston magnetic guide rail 22 moves from the highest point 221 to the middle point 223 corresponding to the circumferential midpoint of the corresponding cylinder guide rail body b, as shown in Figure 5 ;

[0106] During the rotation of the piston 23 from 45° to 90°, the communication area between the left axial groove 24 and the right oil outlet hole 14 gradually increases from zero at 45° to a maximum, and the communication area between the right axial groove 25 and the left inlet hole 13 gradually increases from zero at 45° to a maximum. The liquid enters the right volume chamber I through the liquid inlet channel and the right axial groove 25 in sequence. The volume of the right chamber gradually increases, and under the extrusion action of the piston 23, the volume of the left volume chamber D gradually decreases. The liquid in the left volume chamber D is discharged through the left axial groove 24 and the liquid outlet channel in sequence.

[0107] (3) When the piston 23 rotates from 90° to 135°

[0108] When the piston 23 is at 90°, the left axial groove 24 and the right oil outlet hole 14 have a maximum communication area, the right axial groove 25 and the left inlet hole 13 have a maximum communication area, the left volume chamber D has a maximum liquid discharge flow, and the right volume chamber I has a maximum liquid inlet flow.

[0109] The measured liquid enters the right volume chamber I through the liquid inlet channel and the right axial groove 25 in sequence, and pushes the piston 23 to continue to move axially to the left to the left end of the axial stroke. The magnetic attraction between the piston magnetic guide rail 22 and the cylinder magnetic guide rail 151 forces the piston magnetic guide rail 22 to continue to rotate and synchronously drive the piston 23 to rotate. The piston magnetic guide rail 22 moves from the middle point 223 to the lowest point 222 corresponding to the circumferential midpoint of the corresponding cylinder guide rail body b.

[0110] In the process of the piston 23 rotating from 90° to 135°, the communication area of the left axial groove 24 with the right oil outlet hole 14 gradually decreases from the maximum at 90° to zero, and the communication area of the right axial groove 25 with the left liquid inlet hole 13 gradually decreases from the maximum at 90° to zero;

[0111] The liquid enters the right volume chamber I through the liquid inlet channel and the right axial groove 25 in sequence, and the volume of the right volume chamber I gradually increases to the maximum; the piston 23 presses the left volume chamber D to the left, and the volume of the left volume chamber D gradually decreases to the minimum, and the liquid in the left volume chamber D is discharged through the right axial groove 25 and the liquid outlet channel in sequence.

[0112] (4) When the piston 23 rotates from 135° to 180°

[0113] At 135°, the piston 23 is located at the leftmost end of the axial stroke, the communication area of the left axial groove 24 with the left liquid inlet hole 13 or the right oil outlet hole 14 is zero, and the communication area of the right axial groove 25 with the left liquid inlet hole 13 or the right oil outlet hole 14 is zero, and the left volume chamber D neither takes in liquid nor discharges liquid, and the right volume chamber I neither takes in liquid nor discharges liquid;

[0114] At this time, under the action of inertia, the piston continues to rotate to realize the communication of the left axial groove 24 with the left liquid inlet hole 13 and the communication of the right axial groove 25 with the right oil outlet hole 14, the measured liquid enters the left volume chamber D through the liquid inlet channel and the left axial groove 24 in sequence, and pushes the piston 23 to move to the right along the axial direction to the middle of the axial stroke, the magnetic attraction force between the piston magnetic guide rail 22 and the cylinder magnetic guide rail 151 forces the piston magnetic guide rail 22 to rotate, and synchronously drives the piston 23 to rotate, and the piston magnetic guide rail 22 moves from the lowest point 222 to the middle point 223 corresponding to the middle point of the corresponding cylinder magnetic guide rail 151 in the circumferential direction;

[0115] In the process of the piston 23 rotating from 135° to 180°, the communication area of the left axial groove 24 with the left liquid inlet hole 13 gradually increases from zero at 135° to the maximum, and the communication area of the right axial groove 25 with the left liquid inlet hole 13 or the right oil outlet hole 14 gradually increases from zero at 135° to the maximum;

[0116] The liquid enters the left volume chamber D through the liquid inlet channel and the left axial groove 24 in sequence, and the volume of the left volume chamber D gradually increases; the piston 23 presses the right chamber to the right, and the volume of the right volume chamber I gradually decreases, and the liquid in the right volume chamber I is discharged through the right axial groove 25 and the liquid outlet channel in sequence.

[0117] The above-mentioned cycle is repeated once per 180° rotation of the piston 23, and the piston 23 completes one reciprocating motion per 180° rotation, and the liquid passed is one unit volume, so that the piston 23 completes two reciprocating motions and discharges two unit volumes of liquid in the case of one rotation of 360°, so that the instantaneous flow rate can be converted according to the effective cross-sectional area of the piston 23 and the moving speed of the piston 23.

[0118] As can be seen from the above description, the piston 23 of the embodiment of the application completes two reciprocating motions and realizes two oil suction and discharge in the case of one rotation of 360°, while the conventional piston flowmeter can only perform one liquid intake and discharge, and the application can be miniaturized and the cost can be greatly reduced under the premise of the same measurement range.

[0119] It should be understood that although the quantity terms "first", "second", etc. can be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of the example embodiments.

[0120] The orientation terms such as outer, middle, inner, etc. mentioned or possibly mentioned in the present specification are defined with respect to the structure shown in the drawings, and are relative concepts, so it is possible to change accordingly according to different positions, different use states. Therefore, these or other orientation terms should not be interpreted as limiting terms.

[0121] The above description is only the preferred embodiment of the application, and is not any form and substantial limitation of the application. It should be noted that for ordinary skilled in the art, without departing from the method of the application, some improvements and supplements can also be made, which should be considered as the protection scope of the application. For those skilled in the art, without departing from the spirit and scope of the application, some changes, modifications and equivalent changes can be made according to the above disclosed technical content, which are equivalent embodiments of the application; at the same time, any equivalent changes, modifications and evolution of the above-mentioned embodiments according to the essential technology of the application are still within the scope of the technical solutions of the application.

Claims

1. A piston-type dynamic flowmeter of magnetic force track construction, characterized in that, The flow meter comprises a cylinder (11), the axial direction is defined as the direction along or parallel to the central axis of the cylinder (11), the radial direction is the direction of the diameter of the cross section of the cylinder (11), and the circumferential direction is the direction around the axial direction; The cylinder (11) is provided with a piston (23) reciprocally movable along the axial direction, and the piston (23) is connected with a driving structure for driving the piston (23) to rotate along the circumferential direction while reciprocally moving along the axial direction; The driving structure comprises cylinder magnetic force assemblies (15) symmetrically arranged at the left and right ends of the cylinder (11) with respect to the cross section of the cylinder (11) and piston magnetic force assemblies (21) symmetrically arranged at the left and right ends of the piston (23) with respect to the cross section of the piston (23), the cylinder magnetic force assembly (15) comprises at least one cylinder magnetic force guide rail (151) with magnetism, the piston magnetic force assembly (21) comprises at least one piston magnetic force guide rail (22) with magnetism, the piston magnetic force guide rail (22) and the cylinder magnetic force guide rail (151) both extend along the circumferential direction and correspond to each other along the radial direction, and the polarities of the corresponding cylinder magnetic force guide rail (151) and the piston magnetic force guide rail (22) are opposite; The piston magnetic force guide rail (22) is an axial annular curved surface, the curved surface undulates uniformly along the axial direction, the projection of the curved surface in the central axis direction is a circular ring, the curved surface has two highest points (221) and two lowest points (222), the highest points (221) and the lowest points (222) are located on two mutually perpendicular diameters of the circular ring respectively, and the curved surface is symmetrical with respect to the two diameters respectively; The cylinder magnetic force guide rail (151) comprises a pair of cylinder guide rail bodies (b) symmetrically arranged on the cylinder (11), and a single cylinder guide rail body (b) is in the shape of an arc extending along the circumferential direction, and the central angle of the cylinder guide rail body (b) along the circumferential direction is not greater than 90°; When the piston (23) moves along the axial direction, the piston magnetic force guide rail (22) is separated from the corresponding cylinder magnetic force guide rail (151), so that the magnetic attraction force is formed between the curved surface of the piston magnetic force guide rail (22) and the corresponding cylinder magnetic force guide rail (151), which forces the piston (23) to rotate along the circumferential direction while moving along the axial direction; The piston (23) divides the cylinder (11) into a left volume cavity (D) and a right volume cavity (I), the cylinder (11) is respectively provided with an inlet channel and an outlet channel, and the left volume cavity (D) and the right volume cavity (I) are alternately connected to the inlet channel and the outlet channel in the process of reciprocally moving along the axial direction and rotating along the circumferential direction, so that the left volume cavity (D) and the right volume cavity (I) alternately admit liquid and discharge liquid to measure the volume of liquid.

2. The piston-type dynamic flow meter of magnetic force track structure of claim 1, wherein, The central angle of the single cylinder guide rail body (b) is 90°, which is the same as the central angle between the adjacent highest point (221) and the lowest point (222).

3. The magnetic guideway structure piston dynamic flow meter of claim 1, wherein, The distance between any two adjacent piston magnetic guide rails (22) and / or any two adjacent cylinder magnetic guide rails (151) is the same.

4. The magnetic guideway structure piston dynamic flow meter of claim 1, wherein, The cylinder (11) is provided with a pair of magnetic ring fixing grooves (12) at both ends, the pair of magnetic ring fixing grooves (12) are symmetrically arranged on the cylinder (11), the cylinder magnetic force assembly is fixed on the magnetic ring fixing groove (12), and the piston magnetic guide rail (22) is coaxially fixed on the piston (23).

5. The piston dynamic flow meter of claim 4, wherein, The magnetic ring fixing groove (12) is in the form of a frame, and the cylinder guide rail body (b) is clamped into the frame for fixation.

6. The magnetic guideway structure piston dynamic flow meter of claim 1, wherein, The cylinder magnetic force assembly (15) includes three cylinder magnetic guide rails (151), and the three cylinder magnetic guide rails (151) are respectively N-pole, S-pole and N-pole along the radial direction inwardly. The piston magnetic force assembly (21) includes three piston magnetic guide rails (22), and the three piston magnetic guide rails (22) are respectively S-pole, N-pole and S-pole along the radial direction outwardly.

7. The magnetic guideway structure piston dynamic flow meter of claim 1, wherein, The cylinder magnetic force assembly (15) includes three cylinder magnetic guide rails (151), and the three cylinder magnetic guide rails (151) are respectively N-pole, S-pole and N-pole along the radial direction inwardly. The piston magnetic force assembly (21) includes three piston magnetic guide rails (22), and only the piston magnetic guide rail (22) located in the middle has magnetism, and the piston magnetic guide rail (22) located in the middle is N-pole along the radial direction outwardly.

8. The magnetic guideway structure piston dynamic flow meter of claim 1, wherein, The cylinder magnetic force assembly (15) includes three cylinder magnetic guide rails (151), and only the cylinder magnetic guide rail (151) located in the middle has magnetism, and the cylinder magnetic guide rail (151) located in the middle is N-pole along the radial direction inwardly. The piston magnetic force assembly (21) includes three annular piston magnetic guide rails (22), and only the piston magnetic guide rail (22) located in the middle has magnetism, and the piston magnetic guide rail (22) located in the middle is S-pole along the radial direction outwardly.

9. The magnetic guideway structure piston dynamic flow meter of claim 1, wherein, The piston (23) is provided with a shaft shoulder, and the left and right ends of the cylinder (11) and the piston (23) are provided with a sealing sink (3), and the two sink (3) and the shaft shoulder are respectively enclosed to form a left volume cavity (D) and a right volume cavity (I) in the cylinder (11). The outer surface of the shaft shoulder of the piston (23) is provided with two axisymmetric left axial grooves (24) and two axisymmetric right axial grooves (25), the left axial grooves (24) and the right axial grooves (25) are alternately arranged on the outer surface of the piston (23) along the circumferential direction at equal angles, wherein the left axial grooves (24) are communicated with the left volume cavity (D), and the right axial grooves (25) are communicated with the right volume cavity (I). The left end of the cylinder (11) is provided with a left annular groove (A), and the wall surface of the left end of the cylinder (11) is further provided with two axisymmetric left liquid inlet holes (13), one end of the left liquid inlet hole (13) is communicated with the left annular groove (A), and the other end is used for being communicated with the left axial groove (24) or the right axial groove (25); The right end of the cylinder (11) is provided with a right annular groove (K), and the wall surface of the right end of the cylinder (11) is further provided with two axisymmetric right liquid outlet holes (14), one end of the right liquid outlet hole (14) is communicated with the right annular groove (K), and the other end is used for being communicated with the left axial groove (24) or the right axial groove (25); The projection of the left liquid inlet hole (13) and the right liquid outlet hole (14) on the cross section of the cylinder (11) is arranged alternately along the equal angle of the circumference; The left annular groove (A), the left liquid inlet hole (13) are sequentially communicated to form a liquid inlet channel; the right annular groove (K), the right liquid outlet hole (14) are sequentially communicated to form a liquid outlet channel; In the process of reciprocating movement and rotation along the axial direction of the piston (23), the left volume cavity (D), the right volume cavity (I), the left axial groove (24), the right axial groove (25), the liquid inlet channel and the liquid outlet channel have the following corresponding relationship: In the first state: The measured liquid drives the piston (23) to move along the axial direction to the right, and the piston (23) rotates along the circumferential direction under the magnetic force between the cylinder magnetic guide rail (151) and the piston magnetic guide rail (22); the left axial groove (24) is aligned with the left liquid inlet hole (13), the right axial groove (25) is aligned with the right liquid outlet hole (14), the left volume cavity (D) is liquid-in through the left axial groove (24) and the liquid inlet channel in communication, and the right volume cavity (I) is liquid-out through the right axial groove (25) and the liquid outlet channel in communication; In the second state: The piston (23) is located at the rightmost end of the axial stroke, the left axial groove (24) is not communicated with the left liquid inlet hole (13) and the right liquid outlet hole (14), the right axial groove (25) is not communicated with the left liquid inlet hole (13) and the right liquid outlet hole (14), the left volume cavity (D) neither liquid-in nor liquid-out, and the right volume cavity (I) neither liquid-in nor liquid-out; In the third state: The measured liquid drives the piston (23) to move along the axial direction to the left, and the piston (23) rotates along the circumferential direction under the magnetic force between the cylinder magnetic guide rail (151) and the piston magnetic guide rail (22); the right axial groove (25) is aligned with the left liquid inlet hole (13), and the left axial groove (24) is aligned with the right liquid outlet hole (14); the left volume cavity (D) is liquid-out through the left axial groove (24) and the liquid outlet channel in communication, and the right volume cavity (I) is liquid-in through the right axial groove (25) and the liquid inlet channel in communication; In the fourth state: The piston (23) is located at the leftmost end of the axial stroke, the left axial groove (24) is not communicated with the left liquid inlet hole (13) and the right liquid outlet hole (14), the right axial groove (25) is not communicated with the left liquid inlet hole (13) and the right liquid outlet hole (14), the left volume cavity (D) neither admits liquid nor discharges liquid, and the right volume cavity (I) neither admits liquid nor discharges liquid.

10. The magnetic guideway structure piston dynamic flow meter of claim 1, wherein, The flowmeter further comprises a linear velocity sensor connected with the piston (23), and the linear velocity sensor is used for detecting the axial moving speed of the piston (23) to measure the liquid flow based on the axial moving speed and the liquid volume.

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