CN212007357U - Flow meter - Google Patents

Abstract

A flow meter (1) comprising: a measuring tube (10) providing a channel (11) for receiving a fluid to be measured; a measuring electrode (20) which penetrates through the pipe wall of the middle part of the measuring pipe (10) and can be contacted with the fluid to be measured in the channel (11) for generating an electromotive force signal related to the flow rate of the fluid to be measured; the circuit board (30) is electrically connected with the measuring electrode (20) and is used for receiving the electromotive force signal and determining the flow information of the fluid to be measured according to the electromotive force signal; and at least one grounding electrode (40), wherein a first pole of the at least one grounding electrode (40) is embedded in the pipe wall of the end part of the measuring pipe (10) and can be contacted with the fluid to be measured in the channel (11), and a second pole of the at least one grounding electrode (40) is fixedly connected with a power ground of a circuit board (30) and can enable the fluid to be measured flowing through the end part of the measuring pipe (10) to be grounded.

Description

Flow meter

Technical Field

The present disclosure relates to the field of electronic technology, and more particularly, to a flow meter.

Background

Along with the development of unmanned aerial vehicle technology, unmanned aerial vehicle's application is more and more extensive, if unmanned aerial vehicle has used in transportation and agricultural field. In order to improve the control accuracy of spraying and the accuracy of calculation of the sprayed amount, a flow meter is used.

Because the signal detected by the flowmeter is a differential signal, the flowmeter needs a potential reference point and needs to be grounded, namely, the circuit board is connected with the water flow, and the existing grounding modes comprise a metal joint grounding mode and an electrode grounding mode. However, both grounding methods cannot satisfy the requirements of users on production cost and detection reliability at the same time.

SUMMERY OF THE UTILITY MODEL

In view of this, the present disclosure provides a flow meter comprising a measurement tube, a measurement electrode, a circuit board, and at least one ground electrode. Wherein the measurement tube provides a channel for receiving a fluid to be measured; the measuring electrode penetrates through the pipe wall in the middle of the measuring pipe and can be contacted with the fluid to be measured in the channel, and the measuring electrode is used for generating an electromotive force signal related to the flow of the fluid to be measured; the circuit board is electrically connected with the measuring electrode and used for receiving the electromotive force signal and determining the flow information of the fluid to be measured according to the electromotive force signal; in the detection process, a first pole of at least one grounding electrode is embedded in the pipe wall of the end part of the measuring pipe and can be contacted with the fluid to be detected in the channel, and a second pole of the grounding electrode is fixedly connected with a power ground of a circuit board, so that the fluid to be detected flowing through the end part of the measuring pipe is grounded.

In some embodiments of the present disclosure, the ground electrode is a plate-like structure.

In some embodiments of the present disclosure, the ground electrode comprises a stamped metal plate.

In some embodiments of the present disclosure, the measurement tube is a plastic tube, and the ground electrode is fixed to the measurement tube by means of in-mold injection.

In some embodiments of the present disclosure, the material of the ground electrode comprises a corrosion resistant metallic material.

In some embodiments of the present disclosure, the circuit board is fixed on the ground electrode by a fixing member.

In some embodiments of the present disclosure, the fixing member includes at least one of a screw member or a snap member.

In some embodiments of the present disclosure, at least one of the ground electrodes comprises a first ground electrode and a second ground electrode; and a first contact position of the first ground electrode and a second contact position of the second ground electrode are respectively located on both sides of a portion where the measuring electrode is inserted into the measuring pipe, the first contact position being a position where one pole of the first ground electrode is fitted into the passage, and the second contact position being a position where one pole of the second ground electrode is fitted into the passage.

In some embodiments of the present disclosure, the measuring electrodes include a first measuring electrode and a second measuring electrode disposed in pairs, the first measuring electrode and the second measuring electrode penetrating through a pipe wall of the measuring pipe and separately disposed at both sides of the measuring pipe for forming an electromotive force signal proportional to a flow rate of the fluid to be measured.

In some embodiments of the present disclosure, the flow meter further comprises: and the magnetic field generating structure is arranged on the outer side of the measuring pipe and used for generating a magnetic field, and an included angle between the direction of the magnetic field and the direction of a connecting line of the first measuring electrode and the second measuring electrode is less than or equal to 10 degrees.

In some embodiments of the present disclosure, the direction of the magnetic field is substantially parallel to the direction of the line connecting the first measuring electrode and the second measuring electrode.

In some embodiments of the present disclosure, the magnetic field generating structure comprises: an excitation coil or an excitation coil and at least one of: a coil bobbin and an iron core.

In some embodiments of the present disclosure, a direction of the connecting line, an axial direction of the exciting coil, and an axial direction of the measuring pipe are orthogonal to each other.

In some embodiments of the present disclosure, the circuit board comprises: an electrode plate and a main plate. The electrode plate is electrically connected with the measuring electrode and used for arranging the measuring electrode and determining an output signal by processing an electromotive force signal collected by the measuring electrode; the main board is electrically connected with the electrode plate and used for processing the output signal to determine the flow information of the fluid to be detected.

In some embodiments of the present disclosure, an interface is disposed on the motherboard.

In some embodiments of the present disclosure, the main board is plugged onto the electrode plate through a plug connector.

In some embodiments of the present disclosure, the measurement electrodes comprise a first measurement electrode and a second measurement electrode arranged in pairs; and the electrode plate comprises a first sub-electrode plate and a second sub-electrode plate which are arranged in pair and electrically connected with each other, the first measuring electrode is arranged on the first sub-electrode plate, and the second measuring electrode is arranged on the second sub-electrode plate.

In some embodiments of the present disclosure, the first sub-electrode plate and the second sub-electrode plate are connected by a flexible circuit to form a signal detection loop.

In some embodiments of the present disclosure, an angle between a plane in which the signal detection loop is located and a direction of the magnetic field generated by the magnetic field generating structure is less than or equal to 10 degrees.

In some embodiments of the present disclosure, the plane of the signal detection loop is substantially parallel to the direction of the magnetic field generated by the magnetic field generating structure.

In some embodiments of the present disclosure, the measurement tube includes a plurality of channels.

In some embodiments of the present disclosure, each of the plurality of channels is configured with a measurement electrode.

In some embodiments of the present disclosure, the circuit board comprises a plurality of pairs of sub-electrode plates; the adjacent two pairs of sub-electrode plates are arranged in a mirror image mode.

In some embodiments of the present disclosure, the plurality of channels share the ground electrode.

In some embodiments of the present disclosure, the flow meter further comprises: and the sealing ring is arranged between the measuring electrode and the measuring pipe so as to realize the sealing connection between the measuring electrode and the measuring pipe.

In some embodiments of the present disclosure, the seal ring comprises: a flat pad, a spring pad or a rubber pad.

In some embodiments of the present disclosure, the flow meter further comprises: shell and foam. Wherein the housing is used for accommodating the measuring tube and the circuit board; the foam is arranged on at least one side in the shell.

In some embodiments of the present disclosure, the circuit board includes a flexible circuit against which the foam abuts.

In some embodiments of the present disclosure, the casing is further provided with an inlet pipe and an outlet pipe, wherein the inlet pipe and the outlet pipe are respectively communicated with the measuring pipe.

In some embodiments of the present disclosure, the circuit board includes a power circuit, an arithmetic circuit, and an amplifying circuit, and the power or the output signal is provided through the electrical connector.

In some embodiments of the present disclosure, a first pole of at least one ground electrode is embedded in a wall of the end portion of the measuring tube and is capable of contacting the fluid to be measured in the channel, and a second pole of the ground electrode is fixedly connected to a power ground of the circuit board, thereby achieving grounding of the fluid to be measured flowing through the end portion of the measuring tube. The above method adopts the grounding path of the fluid-grounding electrode-circuit board to be tested, and the grounding path is shorter, so that the fluid-grounding electrode-circuit board is not easy to be interfered and is reliably grounded. Meanwhile, the first pole of the grounding electrode is embedded in the pipe wall of the end part of the measuring pipe, so that the assembly difficulty of the grounding electrode and parts related to the grounding electrode in the related technology is effectively reduced, and the production cost of the flowmeter is reduced on the basis of improving the reliability of the flowmeter.

In some embodiments of the present disclosure, the fluid to be tested is directly connected to the power ground via the ground electrode, which helps to improve the reliability of the ground. The circuit board has no problems of galvanic corrosion, over-restraint and the like of a metal joint/shell, and the like, and also has no problems of electrode sealing and fixing, so that a sealing ring and a screw are saved, the material and assembly cost is reduced, and the structure is more compact.

Drawings

The above and other objects, features and advantages of the present disclosure will become more apparent from the following description of embodiments of the present disclosure with reference to the accompanying drawings, in which:

FIG. 1 schematically illustrates a cross-sectional view of a flow meter of the prior art;

FIG. 2 schematically illustrates a cross-sectional view of another flow meter of the prior art;

FIG. 3 schematically illustrates a schematic diagram of a measurement tube and ground electrode configuration according to an embodiment of the disclosure;

FIG. 4 schematically illustrates a schematic diagram of a ground electrode according to an embodiment of the present disclosure;

FIG. 5 schematically illustrates a structural schematic of a measurement tube and a ground electrode according to another embodiment of the present disclosure;

fig. 6 schematically illustrates a structural schematic of a ground electrode according to another embodiment of the present disclosure;

FIG. 7 schematically illustrates a perspective view of a flow meter according to an embodiment of the disclosure;

FIG. 8 schematically illustrates a front view of the flow meter of FIG. 7;

FIG. 9 schematically illustrates a cross-sectional view of the flow meter of FIG. 7 in the direction A-A';

FIG. 10 schematically illustrates a cross-sectional view of the flow meter of FIG. 7 in the direction B-B';

FIG. 11 schematically illustrates a cross-sectional view of the flow meter of FIG. 7 in the direction C-C';

FIG. 12 schematically illustrates a cross-sectional view of the flow meter of FIG. 7 in the direction D-D'; and

fig. 13 schematically shows a top view of the flow meter of fig. 7.

[ description of the drawings ]

1-a flow meter;

10-measuring tube; 11-a channel; 12-measuring electrode through holes; 13-a water inlet; 14-water inlet joint; 15-water outlet; 16-water outlet joint;

20-a measuring electrode; 21-a first measuring electrode; 22-a second measuring electrode;

30-a circuit board; 31-a main board; 32-an electrode plate; 33-an electrical connector; 34-a flexible circuit; 35-a sub-electrode plate; 36-a plug-in unit; 37-a shield; 38-waterproof plug; 39-electrode plate fixing screw;

40-a ground electrode; 41-a first ground electrode; 42-a second ground electrode; 43-a fixture;

50-a magnetic field generating structure; 51-an excitation coil; 52-a coil former; 53-iron core;

60-a housing; 61-upper cover; 62-lower cover; 63-foam cotton; 64-a gasket; 65-locking the nut; 66-flange nuts; 67-sealing ring; 68-union nut.

Detailed Description

Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. It should be understood that the description is illustrative only and is not intended to limit the scope of the present disclosure. One or more embodiments may be practiced without these specific details. In the following description, descriptions of well-known structures and techniques are omitted so as to not unnecessarily obscure the concepts of the present disclosure.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The terms "comprises," "comprising," and the like, as used herein, specify the presence of stated features and/or components, but do not preclude the presence or addition of one or more other features or components.

All terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art and are to be interpreted as having a meaning that is consistent with the context of this specification and not in an idealized or overly formal sense expressly so defined herein.

Where a convention analogous to "at least one of A, B and C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B and C" would include but not be limited to systems that have a alone, B alone, C alone, a and B together, a and C together, B and C together, and/or A, B, C together, etc.). The terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more features.

To facilitate understanding of the flow meter provided by the embodiments of the present disclosure, a flow meter in the related art is exemplarily described below with reference to fig. 1 to 2.

Along with plant protection unmanned aerial vehicle's popularization gradually, requirement to spraying the precision is higher and higher. The spraying flow is low, so that the spraying is leaked or the protection is not in place, and the high flow causes adverse effects such as seedling burning. In addition, the sprayed amount is an important parameter during plant protection operation, the precision of the existing liquid level meter is limited, and the statistical operation area of the flyer is influenced. In order to improve the control accuracy of spraying and the accuracy of calculation of the sprayed amount, a flow meter is used.

Since the signal detected by the flowmeter is a differential signal, the electromagnetic flowmeter needs a potential reference point and needs to be grounded, for example, a circuit board needs to be connected with a fluid to be tested (such as a liquid to be sprayed, the main component of which includes but is not limited to water) to realize the grounding of the fluid to be tested.

Fig. 1 schematically shows a cross-sectional view of a flow meter of the conventional art.

As shown in fig. 1, the grounding method adopted is a metal joint grounding method, and the grounding path of the fluid to be measured is as follows: fluid to be tested-metal connector-metal housing-circuit board. For example, the metal joint is contacted with water, the metal joint is also electrically connected with the metal shell, and the metal shell is conducted with the circuit board to realize water flow grounding.

This way of grounding the metal contacts has several disadvantages. For example, the grounding path is long and is susceptible to external interference, and if any one of the plurality of connections is abnormal, normal grounding cannot be performed. For another example, the inlet metal fittings, outlet metal fittings, cover and housing must be metal, adding to the weight and cost of the flowmeter. For example, galvanic corrosion is likely to occur at the joint between the metal joint and the metal case, which affects the grounding reliability. For example, the circuit board is connected to both the measuring tube and the metal housing, which requires high precision in manufacturing and assembly, and if errors occur, the circuit board will not touch or deform under stress and even be damaged. In summary, the conventional metal joint grounding method has the disadvantages of long grounding path, high possibility of interference, high weight and cost, unreliable grounding, high requirements on manufacturing and assembling precision and the like.

Fig. 2 schematically shows a cross-sectional view of another flow meter of the prior art.

As shown in fig. 2, the grounding method adopted is a metal joint grounding method, and the grounding path of the fluid to be measured is as follows: fluid to be tested-ground electrode-circuit board. For example, the metal electrode is in contact with water, and the metal electrode is also conducted with the circuit board, so that the water flow is communicated with the circuit. The grounding mode has the problems of difficult sealing of the grounding electrode, multiple fixing screws of the electrodes (including the grounding electrode and the measuring electrode), difficult assembly, inconvenient maintenance and the like. As shown in fig. 2, the flow meter includes: mainboard, plate electrode A, plate electrode B, detection electrode, delivery port telluric electricity field and water inlet telluric electricity field, in order to assemble these functional unit, use a plurality of fixed auxiliary members such as plate electrode A fixed screw, plate electrode B fixed screw, mainboard fixed screw, sealing washer, bring very big inconvenience for the equipment of flowmeter. In addition, the electrode grounding method has the problems of complicated structure, difficult assembly, water leakage risk and the like.

Based on the fact that the grounding technology cannot meet the user requirements in the existing flowmeter, the flowmeter provided by the disclosure solves many problems of an existing metal joint/shell indirect grounding mode and an electrode grounding mode by adopting a mode of grounding of an embedded metal sheet.

The flowmeter provided by the embodiment of the disclosure comprises: a measuring tube, a measuring electrode, a circuit board and a ground electrode. Wherein the measuring tube provides a passage for receiving a fluid to be measured. And the measuring electrode penetrates through the pipe wall in the middle of the measuring pipe and can be contacted with the fluid to be measured in the channel, and is used for generating an electromotive force signal related to the flow of the fluid to be measured. And the circuit board is electrically connected with the measuring electrode and is used for receiving the electromotive force signal and determining the flow information of the fluid to be measured according to the electromotive force signal. The first pole of at least one grounding electrode is embedded in the pipe wall of the end part of the measuring pipe and can be contacted with the fluid to be measured in the channel, and the second pole of the grounding electrode is fixedly connected with the power ground of the circuit board, so that the fluid to be measured flowing through the end part of the measuring pipe is grounded. Therefore, the grounding path of the fluid-grounding electrode-circuit board to be measured is short, interference is not prone to occurring, grounding is reliable, meanwhile, due to the fact that the first pole of the grounding electrode is embedded into the pipe wall of the end portion of the measuring pipe, assembly difficulty of the grounding electrode and parts related to the grounding electrode in the related technology is greatly reduced, and production cost of the flow meter is reduced on the basis of improving reliability of the flow meter.

The flow meter provided by the present disclosure will be described in detail below with reference to fig. 3 to 13.

Fig. 3 schematically illustrates a structural schematic of a measurement tube and a ground electrode according to an embodiment of the disclosure.

As shown in fig. 3, the measurement tube 10 may comprise one or more channels 11, at least one end of the measurement tube 10 being provided with a ground electrode 40. When the measurement pipe 10 includes a plurality of passages 11, the inlet and outlet of each of the plurality of passages 11 may be used individually, or the inlet or outlet of the plurality of passages 11 may be shared. The channel 11 is used for containing a fluid to be tested, and the fluid to be tested is a fluid with certain conductivity, including but not limited to: electrolyte, water, diluted pesticides, liquid fire extinguishing agents, and the like.

The grounding electrode 40 may penetrate through the wall of the measuring tube 10, or be disposed on at least one end of the measuring tube 10, so that when the fluid to be tested is subjected to a flow rate test, one pole of the grounding electrode 40 may contact the fluid to be tested, and the other pole is electrically connected to the grounding circuit of the circuit board 30, thereby grounding the fluid to be tested. The circuit board 30 may be fixed to the ground electrode 40 by a fixing member 43, such as a bolt, etc., and the circuit board 30 may be fixed to the T-shaped connecting end of the ground electrode 40, so that the circuit board 30 and the ground electrode 40 may be electrically connected to each other.

Fig. 4 schematically illustrates a structural schematic of a ground electrode according to an embodiment of the present disclosure.

As shown in fig. 4, the measuring tube 10 is a plastic tube, and the ground electrode 40 is fixed to the measuring tube 10 by means of in-mold injection. Specifically, the measurement pipe 10 may be manufactured by insert molding, such as placing the ground electrode 40 in a mold, and then forming the measurement pipe 10 in the mold by injection molding.

The plastic tubing may be made from synthetic resins, such as polyester. For example, thermoplastic or thermoset plastic tubes may be used, and materials that may be used include, but are not limited to: polyvinyl chloride, polyethylene, polypropylene, polyoxymethylene, phenolic plastic, and the like.

The material of the ground electrode 40 includes corrosion resistant metallic materials including, but not limited to: stainless steel, titanium alloy and other corrosion-resistant conductive materials. Can be made by stamping, forming, forging, etc.

When the measurement pipe 10 includes a plurality of passages 11, and the plurality of passages 11 share an inlet or an outlet, the ground electrode 40 may be disposed at a position offset from the passages 11 at one end in common to reduce the influence of the ground electrode 40 on the fluid to be measured in the passages 11. When the measurement pipe 10 includes a single or a plurality of passages 11, and each passage 11 individually uses an inlet and an outlet, the exposed length of the ground electrode 40 in each passage 11 is kept as uniform as possible, and the specific exposed length is not limited herein. For example, only the tip end surface of the ground electrode 40 is in contact with the fluid to be measured, or the ground electrode 40 having a prescribed length is in contact with the fluid to be measured, or the ground electrode 40 penetrates the entire measurement pipe 10.

In one embodiment, the measuring electrode 20 may extend through the wall of the middle portion of the measuring tube 10 and may be in contact with the fluid to be measured in the channel 11, for example, the measuring electrode 20 may extend through the wall of the measuring tube 10 through the through hole 12 of the measuring electrode 20. In addition, the measuring electrode 20 may be fixed in the measuring tube 10 by injection molding, which is not limited herein. The measuring electrode 20 is used to generate an electromotive force signal related to the flow rate of the fluid to be measured.

The circuit board 30 is electrically connected to the measuring electrode 20, and is configured to receive the electromotive force signal and determine flow information of the fluid to be measured according to the electromotive force signal. The circuit board 30 includes circuitry similar to conventional technology. It should be noted that the circuit board 30 may include a sub circuit board for processing a weak signal and a sub circuit board for processing a strong signal, and the sub circuit board for processing a weak signal and the sub circuit board for processing a strong signal may be integrally arranged or separately arranged. For example, the circuit board 30 includes a power supply circuit, an arithmetic circuit, and an amplification circuit, and supplies power or outputs signals through the electrical connector 33.

The printed circuit board 30 can be fastened to the ground electrode 40, to the housing 60 of the flowmeter 1, or to the measuring tube 10. In one embodiment, the circuit board 30 is secured to the ground electrode 40 by fasteners 43. Further, the fixing may be performed by welding or the like.

For example, the fixing member 43 includes at least one of a screw member and a snap member. The screw connector can be a screw, a screw rod and the like, and the clamping connector can be a clamp and the like which can generate certain elastic deformation. If the circuit board 30 is fixed to the ground electrode 40, the electrical connection between the circuit board 30 and the ground electrode 40 may be achieved by conductive fixing members 43, such as metal screws, and the like.

As shown in fig. 4, when a fixing structure is provided on the extension of the ground electrode 40 (referring to fig. 3, two through holes, such as screw holes, are provided on the T-shaped structure of the ground electrode 40), the circuit board 30 can be fixed by the fixing structure, for example, the circuit board 30 can be fixed on the ground electrode 40 by using the two through holes and screws.

In one embodiment, at least one of the ground electrodes 40 includes a first ground electrode 41 and a second ground electrode 42.

Fig. 5 schematically shows a schematic of the structure of a measurement tube and a ground electrode according to another embodiment of the present disclosure.

As shown in fig. 5, two ground electrodes 40 are provided on the measurement pipe 10: a first ground electrode 41 and a second ground electrode 42. A first contact position of the first ground electrode 41, where one pole of the first ground electrode 41 is fitted into the passage 11, and a second contact position of the second ground electrode 42, where one pole of the second ground electrode 42 is fitted into the passage 11, are located on both sides of a portion where the measurement electrode 20 is inserted into the measurement pipe 10, respectively. As shown in fig. 5, the first contact position and the second contact position are located on both sides of the measurement electrode through-hole 12, respectively. In one embodiment, the first contact location and the second contact location are located at both ends of one channel 11, respectively.

Fig. 6 schematically shows a structural schematic of a ground electrode according to another embodiment of the present disclosure.

As shown in fig. 6, the ground electrode 40 may serve as a second ground electrode 42, and the second ground electrode 42 may have a plate-like structure. The plate-like structure may include a bent portion (shown with reference to fig. 5) to facilitate connection with the circuit board 30. The ground electrode 40 comprises a stamped metal plate. As shown in fig. 6, when the flow meter 1 includes a plurality of channels 11 and outlets of the plurality of channels 11 are separated from each other, a through hole may be provided on the ground electrode 40 for each channel 11 to pass the fluid to be measured. The first ground electrode 41 and the second ground electrode 42 cooperate to secure the circuit board 30 to the ground electrode 40 and to ground the fluid to be measured.

Fig. 7 schematically illustrates a perspective view of a flow meter according to an embodiment of the disclosure.

As shown in fig. 7, the flow meter 1 further includes: a housing 60. The housing 60 serves to accommodate the measuring tube 10 and the circuit board 30. The housing 60 may be a metal housing or a plastic housing. That is, since the ground path does not pass through the housing 60, the housing 60 may be electrically insulated. The housing 60 may include an upper cover 61 and a lower cover 62.

In addition, an interface, such as a pin, is provided on the main board 31 to facilitate quick connection of cables. Accordingly, the flow meter 1 may further include an electrical connector 33 for connecting to an external cable for outputting sensed flow information and receiving external power.

Fig. 8 schematically illustrates a front view of the flow meter of fig. 7.

As shown in fig. 8, a passage inlet is provided at an intermediate position of the upper cover 61, and the plurality of passages 11 share one inlet. The inlet may be connected to external piping by a water inlet fitting 14. The upper cover 61 may be fixed to the lower cover 62 by screws or the like.

The internal structure of the flow meter will be described below with reference to fig. 9 to 12.

FIG. 9 schematically illustrates a cross-sectional view of the flow meter of FIG. 7 in the direction A-A'. FIG. 10 schematically illustrates a cross-sectional view of the flow meter of FIG. 7 in the direction B-B'. FIG. 11 schematically illustrates a cross-sectional view of the flow meter of FIG. 7 in the direction C-C'. FIG. 12 schematically illustrates a cross-sectional view of the flow meter of FIG. 7 in the direction D-D'.

In one embodiment, the measuring electrode 20 includes a first measuring electrode 21 and a second measuring electrode 22 disposed in pairs, the first measuring electrode 21 and the second measuring electrode 22 penetrating through a pipe wall of the measuring pipe 10 and being separately disposed on both sides of the measuring pipe 10 for forming an electromotive signal proportional to a flow rate of the fluid to be measured.

In one embodiment, to reduce the interference of strong signals to weak signals, the circuits in the circuit board 30 related to strong signal processing and the circuits related to weak signal processing may be separately disposed. For example, the circuit board 30 includes: an electrode plate 32 and a main plate 31. The electrode plate 32 is electrically connected to the measuring electrode 20, and is configured to set the measuring electrode 20, and determine an output signal by processing the electromotive force signal collected by the measuring electrode 20, where the output signal may represent flow information of the fluid to be measured. The main board 31 is electrically connected to the electrode plate 32, for example, electrically connected through an electrical connector 33, and is configured to determine flow information of the fluid to be measured by processing the output signal.

For example, the main plate 31 is plugged to the electrode plate 32. Such as electrical connection between the main board 31 and the electrode plate 32 via the plug 36.

As shown in fig. 9, the wall of the measuring tube 10 is penetrated by the measuring electrode 20, and during the test, one pole of the measuring electrode 20 can contact with the fluid to be measured in the channel 11 to detect the electromotive force of the fluid to be measured. The measuring electrode 20 is fixed to the electrode plate 32 by an electrode plate fixing screw 39. The main plate 31 is fixedly provided on the first ground electrode 41 and the second ground electrode 42.

The first ground electrode 41 is in contact with the fluid to be measured at the inlet of the channel to ground the fluid to be measured at the inlet. A second ground electrode 42 is in contact with the fluid to be measured at the outlet of the channel to ground the fluid to be measured at the outlet. The arrangement mode of the double grounding electrodes 40 in the single channel 11 is beneficial to improving the flow detection precision, and residual charges can be eliminated at the outlet.

The inlet of the passage 11 may be connected to a water inlet joint 14 so that an external pipe communicates with the passage 11 through the water inlet joint 14. The outlet of the passage 11 may be connected to a water outlet connector 16 so that an external pipe communicates with the passage 11 through the water outlet connector 16.

In addition, in order to prevent the flowmeter 1 from being damaged by electric leakage or causing damage to a user, a waterproof plug 38 may be provided on the flowmeter 1.

As shown in fig. 10, a washer 64, a lock nut 65, a flange nut 66 and a seal ring 67 may be provided at the water inlet 13. Wherein the washer 64 reduces the probability of water leakage between the locking nut 65 and the water inlet joint 14. The packing 67 reduces the probability of water leakage between the flange nut 66 and the upper cover 61. A joint nut 68 and a sealing ring 67 can be arranged at the water outlet 15 to reduce the probability of water leakage at the water outlet joint 16.

In addition, a sealing ring 67 may be disposed between the upper cover 61 and the lower cover 62 to seal the housing 60.

In one embodiment, the flow meter 1 is an electromagnetic flow meter. The flow meter 1 further includes: a magnetic field generating structure 50, the magnetic field generating structure 50 being disposed outside the measuring tube 10 for generating a magnetic field, a direction of the magnetic field being at an angle of 80 degrees or more and 100 degrees or less to a direction of a line connecting the first measuring electrode 21 and the second measuring electrode 22. For example, the included angle is 81 °, 83 °, 84 °, 86 °, 88 °, 89 °, 90 °, 92 °, 95 °, 96 °, 98 °, or 99 °, etc. Optionally, the direction of the magnetic field and the direction of the line connecting the first measuring electrode 21 and the second measuring electrode 22 are perpendicular to each other. Ions in the water flow are deflected by the magnetic field to generate an electromotive force in the front-rear direction, and the magnitude of the electromotive force is detected by the first measuring electrode 21 and the second measuring electrode 22 which are provided in pair.

Wherein the magnetic field generating structure 50 includes: the excitation coil 51 or the excitation coil 51 and at least one of: a bobbin 52 and a core 53. For example, the exciting coil 51 is disposed outside the measuring pipe 10, and the direction of the generated magnetic field is perpendicular to the axial center of the measuring electrode 20. For another example, in order to facilitate fixing of the excitation coil 51, a coil former 52 may be provided, and the coil former 52 may be fixed to the measurement pipe 10. For another example, in order to reduce the influence of the leakage flux on the test accuracy, the iron core 53 may be provided in the bobbin 52. The iron core 53 can restrict the magnetic field direction and effectively reduce the magnetic leakage.

In one embodiment, the direction of the line connecting the first measuring electrode 21 and the second measuring electrode 22, the axial direction of the exciting coil 51, and the axial direction of the measuring pipe 10 are orthogonal to each other. For example, the detection principle of electromagnetic induction is adopted, the magnetic field, the measuring tube 10 and the measuring electrode 20 are orthogonally distributed, the induced electromotive force is in direct proportion to the magnetic field intensity and the water flow speed, and the voltage is detected by the measuring electrode 20 to reversely push the water flow. The water flow direction is from the inlet to the outlet. The magnetic field is generated by the exciting coil 51, and the direction of the magnetic field is perpendicular to the direction of the water flow.

As shown in fig. 11, the first sub-electrode plate and the second sub-electrode plate are connected by a Flexible Circuit 34 (FPC) to form a signal detection loop.

In order to reduce the influence of the magnetic field on the signal detection loop, the angle between the plane of the signal detection loop and the direction of the magnetic field generated by the magnetic field generating structure 50 may be less than or equal to 10 degrees. For example, the included angle is 0 °, 1 °, 2 °, 3 °, 5 °, 6 °, 8 °, 9 °, or 10 °, etc. Optionally, the plane of the signal detection loop and the direction of the magnetic field generated by the magnetic field generating structure 50 are parallel to each other. In addition, in order to further reduce signal interference, such as interference from the outside world to the sub-electrode plate 35 or interference from a strong signal of the main board 31 to a weak signal of the sub-electrode plate 35, a shielding cover 37 may be further disposed on the sub-electrode plate 35.

In addition, in order to reduce the vibration of the FPC relative to the magnetic field caused by external vibration and the like, and further to reduce the influence of induced electromotive force generated by the cutting magnetic field on the measurement result, the flowmeter 1 may further include foam 63 disposed on at least one side in the casing 60 to provide mechanical support for the FPC. Optionally, the circuit board 30 includes a flexible circuit 34, and the foam 63 abuts against the flexible circuit 34 to reduce the vibration amplitude of the flexible circuit 34, so as to reduce the induced electromotive force generated by the cutting magnetic field and improve the measurement accuracy.

In one embodiment, in order to avoid water leakage in the gap between the measuring electrode 20 and the measuring tube 10, a sealing ring 67 may be provided at the measuring electrode 20. The flow meter 1 may further include: and a seal 67. A sealing ring 67 may be arranged between the measuring electrode 20 and the measuring tube 10 to achieve a sealed connection between the measuring electrode 20 and the measuring tube 10. Wherein the seal ring 67 includes but is not limited to: a flat pad, a spring pad or a rubber pad.

Along with plant protection unmanned aerial vehicle's popularization gradually, requirement to spraying the precision is higher and higher. The spraying flow is low, so that the spraying is leaked or the protection is not in place, and the high flow causes adverse effects such as seedling burning. In addition, the sprayed amount is an important parameter during plant protection operation, the precision of the existing liquid level meter is limited, and the statistical operation area of the flyer is influenced. In order to improve the control accuracy of spraying and the accuracy of calculation of the sprayed amount, a flow meter is used. However, the current flow meter is a single channel, the number of water pumps is generally multiple, one flow meter can only measure the total flow of multiple pumps, and the flow of each pump cannot be measured. Because of the difference between the water separator and the water pump, the flow rate of each pump at the same rotating speed is different. To ensure uniformity of the spray, a flow calibration for each pump is required. Calibration operations are time consuming and labor intensive, affecting user experience. In order to improve the flow control accuracy of a single pump and the uniformity of flow among a plurality of spray heads and simultaneously remove calibration operation, a good solution is provided by developing a multi-channel flow meter matched with the number of water pumps.

In one embodiment, the measurement pipe 10 includes a plurality of channels 11, such as 2 channels, 3 channels, 4 channels, 6 channels, 8 channels or more, and the like. As shown in fig. 10, the channels may be arranged in parallel, and a plurality of channels may share one water inlet 13.

Accordingly, each of the plurality of channels 11 is configured with a measuring electrode 20, and each measuring electrode 20 is used for measuring the flow of the fluid to be measured in the channel 11 in which it is located.

In one embodiment, the circuit board 30 includes a plurality of pairs of sub-electrode plates 35. Accordingly, two adjacent pairs of sub-electrode plates 35 are arranged in a mirror image. For example, each sub-electrode plate 35 of each pair of sub-electrode plates 35 is disposed on opposite sides of one channel 11. One sub-measuring electrode is provided on each sub-electrode plate 35.

In one embodiment, in order to determine that the measurement results of the channels 11 have the same measurement reference and improve the accuracy of the measurement results, the ground electrode 40 is shared by the channels 11, for example, one sub-ground electrode is shared at the inlet of each channel 11 and one sub-ground electrode is shared at the outlet of each channel 11.

Furthermore, a flow inlet pipe and a flow outlet pipe are provided on the housing 60, wherein the flow inlet pipe and the flow outlet pipe are respectively communicated with the measuring pipe 10.

As shown in fig. 12 and 13, the main board 31 is connected to the ground of the power line, so that the fluid to be tested can be connected to the power ground, and the fluid to be tested is grounded.

The following description will be given by taking a four-channel electromagnetic flowmeter as an example for detecting the water flow rate.

This four-channel electromagnetic flowmeter adopts electromagnetic induction's detection principle, and wherein, magnetic field direction, survey buret 10 axial and measuring electrode 20 three are the orthogonal distribution, and the induced electromotive force is directly proportional with magnetic field intensity and water velocity, can calculate the size of rivers flow through measuring electrode 20 detection voltage.

Four circular pipes (from left to right in fig. 11, pipes 1#, 2#, 3#, and 4#) are arranged in parallel, and the water flow direction is from the water inlet 13 to the water outlet 15. The magnetic field is generated by two groups of magnet exciting coils 51, the two groups of coils are symmetrically arranged in the respective middle parts of the four round pipelines, and are respectively arranged between the pipelines 1# and 2# and between the pipelines 3# and 4#, and the direction of the magnetic field is vertical to the direction of water flow. The coil is composed of a coil rack 52, an iron core 53 and an enameled wire, the iron core 53 is used for restraining the direction of a magnetic field and reducing magnetic leakage, and the coil rack 52 is fixed on the measuring tube 10 through screws. As the coils are symmetrically arranged, the calculation shows that the magnetic field intensity at the centers of the four circular pipelines is basically consistent, and the measurement precision is ensured.

The ions in the water flow are deflected under the action of the magnetic field, an electromotive force along the ion deflection direction is generated, and the magnitude of the electromotive force is detected by adopting a pair of sub-measuring electrodes. The sub-measuring electrodes are arranged along the direction orthogonal to the magnetic field direction and the axial direction of the circular pipeline, and four pairs of sub-measuring electrodes are arranged at the centers of the four circular pipelines in total and are consistent with the quantity of the pipelines. The front and rear sub-electrode plates 35 are pressed on the sub-measuring electrodes. During the measurement, one pole of the sub-measuring electrode is in contact with the water flow, and the other pole is in contact with the circuit board 30. A main board 31 is disposed above one sub-electrode plate 35 for power supply and signal operation and amplification. Pins are arranged on the main board 31 for a quick-plug connection of the flowmeter 1 to a line plug.

The flowmeter 1 includes two types of circuit boards: an electrode plate 32 and a main plate 31. The detection circuit is arranged on the electrode plate 32, and the signal is relatively weak; the power signal and the processing circuit are arranged on the main board 31, the signals are relatively strong, interference of strong signals to weak signals is avoided, and therefore detection accuracy is guaranteed.

The two sub-electrode plates 35 are connected through the FPC to form a signal detection loop, and the FPC wiring ensures that the plane of the signal loop is parallel to the direction of the magnetic field, so that the signal loop is not interfered by the alternating magnetic field. Damping foam 63 is adhered to the FPC to prevent the PFC from vibrating to generate electromagnetic interference.

The inlet and outlet of the electromagnetic flowmeter need to be grounded (connected with water), and the grounding path is water flow-grounding electrode-circuit board. The water current contacts the ground electrode 40, and the ground electrode 40 contacts the circuit board 30, so that the current flows.

The grounding electrode 40 is made of corrosion-resistant metal materials such as stainless steel and titanium alloy, and the grounding electrode 40 is of a plate-shaped structure and can be formed by stamping, so that the cost is low. The grounding electrode 40 is directly molded into the measuring tube 10 in an injection mode, and the grounding electrode 40 is in close contact with the measuring tube 10 to ensure sealing without adding an additional sealing ring. The grounding electrode 40 is provided with a threaded hole which is tightly contacted with the circuit board 30 through a screw, and a conductive copper sheet is arranged around the hole of the circuit board 30, so that the grounding electrode 40 is electrically connected with the circuit board 30.

Two sub-plate electrodes 35 are connected through two left and right FPC, and the connector is arranged in the middle of sub-plate electrodes 35, has guaranteed pipeline 1#, pipeline 2#, and pipeline 3#, pipeline 4# detection return circuit length difference is not big, improves and detects the precision, because annular FPC makes the difficulty, breaks off in the middle of sub-plate electrodes 35 one side, is buckled by a FPC flexible flat board and encircles, then pastes two front and back stiffening plates and forms.

The flowmeter 1 provided by the embodiment of the disclosure adopts the mode of embedding the grounding electrode 40 in the measuring pipe 10 to directly ground the fluid to be measured, and has the advantages of short grounding path, strong anti-interference capability and reliable grounding. In addition, the circuit board 30 has no galvanic corrosion, over-constraint and other problems of the metal joint/shell, and no sealing and fixing problems of the sub-measuring electrodes, so that sealing rings and screws are saved, the material and assembly cost is reduced, and the structure is more compact.

The above is a preferred embodiment of the present disclosure, which should be explained only for understanding the present disclosure and not for limiting the scope of the present disclosure. Furthermore, the features of the preferred embodiments, unless otherwise specified, are applicable to both the method embodiments and the apparatus embodiments, and technical features that may be present in the same or different embodiments may be used in combination without conflict with each other.

It is to be understood that the above definitions of various elements are not limited to the specific structures or shapes mentioned in the embodiments, and that the substitution thereof is easily made by those skilled in the art, and the above described specific embodiments, further detailed description of the purpose, technical solution and advantages of the present disclosure, it is to be understood that the above described are only specific embodiments of the present disclosure and are not to be construed as limiting the present disclosure, and any modification, equivalent substitution, improvement and the like made within the spirit and principle of the present disclosure should be included in the protection scope of the present disclosure.

Claims (30)

1. A flow meter, comprising:

a measuring tube providing a channel for receiving a fluid to be measured;

the measuring electrode penetrates through the pipe wall in the middle of the measuring pipe and can be contacted with the fluid to be measured in the channel, and the measuring electrode is used for generating an electromotive force signal related to the flow of the fluid to be measured;

the circuit board is electrically connected with the measuring electrode and used for receiving the electromotive force signal and determining the flow information of the fluid to be measured according to the electromotive force signal; and

at least one grounding electrode, at least one of which the first pole is embedded in the pipe wall of the end part of the measuring pipe and can be contacted with the fluid to be measured in the channel, and the second pole of the grounding electrode is fixedly connected with the power ground of the circuit board and can lead the fluid to be measured flowing through the end part of the measuring pipe to be grounded.

2. The flowmeter of claim 1 wherein said ground electrode is a plate-like structure.

3. The flowmeter of claim 1 wherein said ground electrode comprises a stamped metal plate.

4. The flowmeter of claim 1 wherein said measurement tube is a plastic tube and said ground electrode is secured to said measurement tube by in-mold injection.

5. The flowmeter of claim 1 wherein the material of said ground electrode comprises a corrosion resistant metallic material.

6. The flowmeter of claim 1 wherein said circuit board is secured to said ground electrode by a fastener.

7. The flowmeter of claim 6, wherein the fixing member comprises at least one of a threaded member or a snap-fit member.

8. The flowmeter of claim 1 wherein at least one of said ground electrodes comprises a first ground electrode and a second ground electrode; and

a first contact position of the first ground electrode and a second contact position of the second ground electrode are respectively located on both sides of a portion where the measurement electrode is inserted into the measurement pipe, the first contact position being a position where one pole of the first ground electrode is fitted into the passage, and the second contact position being a position where one pole of the second ground electrode is fitted into the passage.

9. The flowmeter of claim 1, wherein said measuring electrodes comprise a first measuring electrode and a second measuring electrode arranged in pairs, said first measuring electrode and said second measuring electrode extending through a wall of said measuring tube and being separately arranged on both sides of said measuring tube for forming an electromotive force signal proportional to a flow rate of said fluid to be measured.

10. The flowmeter of claim 9, further comprising:

and a magnetic field generating structure disposed outside the measuring tube and generating a magnetic field having an angle of 80 degrees or more and 100 degrees or less with respect to a direction of a line connecting the first measuring electrode and the second measuring electrode.

11. The flowmeter of claim 10 wherein the direction of said magnetic field is perpendicular to the direction of the line connecting said first measuring electrode and said second measuring electrode.

12. The flowmeter of claim 10, wherein the magnetic field generating structure comprises: an excitation coil or an excitation coil and at least one of: a coil bobbin and an iron core.

13. The flowmeter of claim 12 wherein the direction of said connecting line, the axial direction of said exciter coil, and the axial direction of said measurement pipe are orthogonal to each other.

14. The flowmeter of claim 1, wherein said circuit board comprises:

the electrode plate is electrically connected with the measuring electrode and used for arranging the measuring electrode and determining an output signal by processing an electromotive force signal collected by the measuring electrode; and

and the main board is electrically connected with the electrode plate and is used for processing the output signal to determine the flow information of the fluid to be detected.

15. The flowmeter of claim 14 wherein said motherboard has an interface disposed thereon.

16. The flowmeter of claim 14, wherein said main plate is attached to said electrode plate by a connector.

17. The flowmeter of claim 14 wherein said measuring electrodes comprise a first measuring electrode and a second measuring electrode arranged in pairs; and

the electrode plate comprises a first sub-electrode plate and a second sub-electrode plate which are arranged in pair and electrically connected with each other, the first measuring electrode is arranged on the first sub-electrode plate, and the second measuring electrode is arranged on the second sub-electrode plate.

18. The flowmeter of claim 17, wherein said first sub-electrode plate and said second sub-electrode plate are connected by a flexible circuit to form a signal sensing loop.

19. The flowmeter of claim 18 wherein the angle between the plane of the signal sensing loop and the direction of the magnetic field generated by the magnetic field generating structure is less than or equal to 10 degrees.

20. The flowmeter of claim 18 wherein the plane of the signal sensing loop and the direction of the magnetic field generated by the magnetic field generating structure are parallel to each other.

21. The flowmeter of claim 1 wherein said measurement tube comprises a plurality of channels.

22. The flowmeter of claim 21 wherein each channel of said plurality of channels is configured with a measurement electrode.

23. The flowmeter of claim 22 wherein said circuit board comprises a plurality of pairs of sub-electrode plates;

the adjacent two pairs of sub-electrode plates are arranged in a mirror image mode.

24. The flowmeter of claim 21 wherein said plurality of channels share said ground electrode.

25. The flowmeter of claim 1, further comprising:

and the sealing ring is arranged between the measuring electrode and the measuring pipe so as to realize the sealing connection between the measuring electrode and the measuring pipe.

26. The flowmeter of claim 25 wherein said seal ring comprises: a flat pad, a spring pad or a rubber pad.

27. The flowmeter of claim 1, further comprising:

a housing for accommodating the measurement pipe and the circuit board;

and the foam is arranged on at least one side in the shell.

28. The flowmeter of claim 27, wherein said circuit board comprises a flexible circuit, said foam abutting said flexible circuit.

29. The flowmeter of claim 27 wherein said housing further comprises an inlet tube and an outlet tube, wherein said inlet tube and said outlet tube are in communication with said measurement tube, respectively.

30. The flowmeter of claim 1 wherein said circuit board comprises power circuitry, operational circuitry, amplification circuitry, and power or output signals are provided via electrical connectors.

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