CN212275004U - Electromagnetic flowmeter, sprinkler and movable platform - Google Patents

Abstract

The utility model discloses an electromagnetic flowmeter, a spraying device and a movable platform, wherein the electromagnetic flowmeter comprises a shell, at least two detection electrodes and a signal amplifying circuit in the shell; the signal amplifying circuit comprises at least two amplifying circuits and a differential amplifying circuit; the input ends of the amplifying circuits are respectively connected with one detection electrode, and the amplifying circuits amplify electrode signals of the detection electrodes; at least two input ends of the differential amplifying circuit are respectively connected to the output end of one amplifying circuit, and the output end of the differential amplifying circuit outputs a voltage signal. The electrode signals of the detection electrodes are amplified through the amplifying circuits, then the signals amplified by the at least two amplifying circuits are subjected to differential amplification through the differential amplifying circuits, the signals are subjected to two-stage amplification and can be converted into higher voltage signals, the common mode rejection ratio is higher, and the influence of space power frequency electromagnetic field interference on the measurement precision of the electromagnetic flowmeter can be effectively reduced.

Description

Electromagnetic flowmeter, sprinkler and movable platform

Technical Field

This description relates to flow detection technical field, especially relates to an electromagnetic flow meter, sprinkler and movable platform.

Background

The electromagnetic flowmeter is a new type of flow measuring instrument which is developed rapidly along with the development of electronic technology, and the electromagnetic induction principle is applied to the instrument for measuring the flow of a conductive fluid according to the electromotive force induced when the conductive fluid passes through an external magnetic field.

The electrode type electromagnetic flowmeter is a commonly used electromagnetic flowmeter, but is easily interfered by electromagnetic signals in the environment, such as power frequency signals, to cause inaccurate measurement results.

SUMMERY OF THE UTILITY MODEL

Based on this, this specification provides an electromagnetic flowmeter, sprinkler and movable platform, aims at solving current electromagnetic flowmeter and receives electromagnetic signal interference among the environment easily and arouses technical problem such as measuring result inaccuracy.

In a first aspect, the present specification provides an electromagnetic flowmeter comprising a housing, at least two sensing electrodes, and a signal amplification circuit within the housing;

wherein the signal amplification circuit includes:

the input ends of the amplifying circuits are respectively connected to one detection electrode, and the amplifying circuits amplify electrode signals of the detection electrodes;

at least two input ends of the differential amplification circuit are respectively connected to the output end of one amplification circuit, and the output end of the differential amplification circuit outputs a voltage signal.

In a second aspect, the present specification provides a spray device comprising:

a liquid supply tank;

the water pump is used for pumping liquid from the liquid supply tank;

the spray head is communicated with the water pump, and the water pump conveys liquid to the spray head and sprays the liquid out through the spray head;

the electromagnetic flowmeter is communicated between the liquid supply tank and the water pump, and is used for detecting the flow and/or the flow velocity of the liquid flowing into the water pump from the liquid supply tank.

In a third aspect, the present specification provides a moveable platform comprising:

a movable body;

the spraying device is arranged on the movable main body.

The embodiment of the specification provides an electromagnetic flowmeter, a spraying device and a movable platform, wherein electrode signals of a detection electrode are amplified through an amplifying circuit, then signals amplified by at least two amplifying circuits are subjected to differential amplification through a differential amplifying circuit, the signals can be converted into higher voltage signals after being subjected to two-stage amplification, the common-mode rejection ratio is higher, and the influence of space power frequency electromagnetic field interference on the measurement accuracy of the electromagnetic flowmeter can be effectively reduced.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure as claimed.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present disclosure, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts.

FIG. 1 is a schematic structural diagram of a movable platform provided in an embodiment of the present disclosure;

FIG. 2 is a schematic block diagram of an electromagnetic flow meter provided in an embodiment of the present description;

FIG. 3 is a circuit diagram of a signal amplification circuit according to an embodiment;

FIG. 4 is a schematic view of an angle of an electromagnetic flowmeter according to an embodiment;

FIG. 5 is a schematic view of an alternative angle of an electromagnetic flowmeter according to an embodiment;

FIG. 6 is an exploded schematic view of an electromagnetic flow meter in one embodiment;

FIG. 7 is a schematic cross-sectional view of an angle of an electromagnetic flowmeter according to an embodiment;

FIG. 8 is a schematic cross-sectional view of an angle of an electromagnetic flowmeter according to an embodiment;

FIG. 9 is a schematic cross-sectional view of an angle of an electromagnetic flowmeter according to an embodiment;

FIG. 10 is a schematic cross-sectional view of an angle of an electromagnetic flowmeter according to an embodiment;

FIG. 11 is a schematic view of a housing of an electromagnetic flow meter in one embodiment.

Reference numerals: 1000. a movable platform; 100. a movable body; 200. a spraying device; 10. a liquid supply tank; 20. a water pump; 30. a spray head; 40. an electromagnetic flow meter;

41. a housing; 411. a housing; 412. a conductive layer; 42. a main body support; 43. a catheter; 44. a detection electrode assembly; 441. a detection electrode;

45. a signal acquisition component; 450. a signal amplification circuit; 4501. an amplifying circuit; 4502. a differential amplifier circuit; 4503. a conditioning circuit;

46. a coil assembly; 461. a coil; 462. an iron core; 463. a fixed mount; 47. a control panel;

484. a first ground electrode; 485. a second ground electrode; 494. an electric plug.

Detailed Description

The technical solutions in the embodiments of the present disclosure will be clearly and completely described below with reference to the drawings in the embodiments of the present disclosure, and it is obvious that the described embodiments are some, but not all, of the embodiments of the present disclosure. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments in the present specification without any creative effort belong to the protection scope of the present specification.

The flow diagrams depicted in the figures are merely illustrative and do not necessarily include all of the elements and operations/steps, nor do they necessarily have to be performed in the order depicted. For example, some operations/steps may be decomposed, combined or partially combined, so that the actual execution sequence may be changed according to the actual situation.

Some embodiments of the present description will be described in detail below with reference to the accompanying drawings. The embodiments described below and the features of the embodiments can be combined with each other without conflict.

Fig. 1 is a schematic structural diagram of a movable platform 1000 according to an embodiment of the present disclosure.

Referring to fig. 1, the movable platform 1000 includes a movable body 100 and a spraying device 200, and the spraying device 200 is mounted on the movable body 100.

In some embodiments, the movable platform 1000 is used in the agricultural industry for liquid spraying operations of agricultural products, forest trees, and the like, with pesticides, water, and the like.

For example, the movable body 100 may perform movements such as moving, rotating, turning, and the like, and the movable body 100 may move the spraying device 200 to different positions or different angles to perform a spraying operation in a predetermined area.

For example, the movable platform 1000 may include an agricultural spray truck, an agricultural drone, or a human powered spray device, etc.; or the movable platform 1000 in one form is one of an agricultural spray vehicle, an agricultural drone or a human spray device, and in another form is another of an agricultural spray vehicle, an agricultural drone or a human spray device.

The following description will be given by taking an example in which the movable platform 1000 is an agricultural unmanned aerial vehicle and the spraying liquid is a liquid medicine. It is to be understood that the particular form of the movable platform 1000 is not limited to agricultural drones and is not intended to be limiting herein.

Referring to fig. 1, in some embodiments, a spraying device 200 includes a liquid supply tank 10, a water pump 20, a spray head 30, and an electromagnetic flow meter 40.

Illustratively, the supply tank 10 contains a liquid to be sprayed. The water pump 20 is used to pump liquid from the liquid supply tank 10. The nozzle 30 is connected to the water pump 20, and the water pump 20 supplies the liquid to the nozzle 30 and sprays the liquid through the nozzle 30, thereby performing a spraying operation.

Specifically, the electromagnetic flowmeter 40 is connected between the liquid supply tank 10 and the water pump 20. When the water pump 20 pumps the liquid from the liquid supply tank 10, the liquid in the liquid supply tank 10 flows to the water pump 20 through the electromagnetic flow meter 40, and at this time, the electromagnetic flow meter 40 can detect the flow rate and/or the flow velocity of the liquid flowing from the liquid supply tank 10 into the water pump 20.

It will be appreciated that the number of water pumps 20 may be designed according to the actual requirements, for example one, two, three or more. In some embodiments, the number of the water pumps 20 is plural, for example, two, three, four or more, and the electromagnetic flow meter 40 can detect the flow rate and/or the flow velocity of the liquid flowing from the liquid supply tank 10 into each water pump 20. The water pumps 20 can work simultaneously; one or more of the water pumps 20 can be selected to operate according to actual requirements, and the rest of the water pumps 20 do not operate.

In some embodiments, as shown in fig. 2, the electromagnetic flow meter 40 includes a housing 41, at least two detection electrodes 441, and a signal amplification circuit 450 within the housing 41.

For example, the detection electrode 441 may contact the liquid flowing from the liquid supply tank 10 into each water pump 20. Specifically, the liquid is a conductive fluid, and a polarization voltage is generated between the detection electrode 441 of the electromagnetic flow meter 40 and the conductive fluid. For example, when the conductive fluid flows, a polarization voltage is generated between the detection electrode 441 and the conductive fluid under the action of the magnetic field. Thus, the electrode signal of the detection electrode 441 can be detected by the signal amplification circuit 450.

Specifically, as shown in fig. 3, the signal amplifier circuit 450 includes at least two amplifier circuits 4501, input terminals of the amplifier circuits 4501 are connected to one detection electrode 441, respectively, and the amplifier circuits 4501 amplify electrode signals of the detection electrodes 441.

Illustratively, as shown in fig. 3, the signal amplification circuit 450 includes two amplification circuits 4501, each of which is connected to one of the detection electrodes 441, wherein one of the amplification circuits 4501 amplifies the electrode signal of the detection electrode 441 connected thereto, and the other amplification circuit 4501 also amplifies the electrode signal of the detection electrode 441 connected thereto.

Since the polarization voltage of the detection electrode 441 is weak, a strong signal can be obtained by amplification by the amplifier circuit 4501.

In some embodiments, the amplification of at least two of the amplification circuits 4501 is the same.

Illustratively, the amplification factor of the two amplification circuits 4501 connected to the two detection electrodes 441 of the same pair is the same, and the two detection electrodes 441 of the same pair contact the liquid flowing from the liquid supply tank 10 to a water pump 20.

Illustratively, the amplification factor of the amplifying circuit 4501 may be 3-10 times, for example, 6 times. It is possible to prevent the power frequency interference signal from being too strong due to the too large amplification factor of the amplifying circuit 4501.

Specifically, as shown in fig. 3, the signal amplification circuit 450 further includes a differential amplification circuit 4502, at least two input terminals of the differential amplification circuit 4502 are respectively connected to an output terminal of one amplification circuit 4501, and an output terminal of the differential amplification circuit 4502 outputs a voltage signal.

For example, as shown in fig. 3, two input terminals of the differential amplifier circuit 4502 are connected to one amplifier circuit 4501, and the amplified signals output from the two amplifier circuits 4501 are differentially amplified, so that a differential mode signal between the two amplifier circuits 4501 can be amplified, and a common mode signal between the two amplifier circuits 4501 can be suppressed.

Specifically, the interference of the power frequency (e.g., 50 ± 1Hz or 60 ± 1Hz) signal is applied to the two detection electrodes 441 and/or the amplifying circuit 4501 in fig. 2 and 3; the signals received by the two input ends of the differential amplification circuit 4502 both include interference of a power frequency signal, and when the signals received by the two input ends are differentially amplified, the differential amplification circuit 4502 inhibits amplification of interference of the power frequency signal, so that influence of the power frequency interference can be reduced, and detection precision is improved.

Specifically, when the amplification factors of the amplifying circuits 4501 are the same, the power frequency signal interference at the two input ends of the differential amplifying circuit 4502 can be cancelled, and the differential amplifying circuit 4502 only amplifies the difference part of the signals output by the two amplifying circuits 4501, so that the common mode rejection ratio of the signal amplifying circuit 450 can be kept at a higher level, and the spatial power frequency interference to which the detection electrode 441 and the like are coupled is prevented from affecting the performance of the electromagnetic flowmeter 40.

The difference in the signals output by the two amplification circuits 4501 is partially amplified by the different polarization voltages of the two detection electrodes 441. Further, by further amplifying the differential amplifier circuit 4502, the output voltage signal of the differential amplifier circuit 4502 becomes stronger, and the detection accuracy improves.

Specifically, the flow rate detected by the detection electrode 441 can be determined based on the output voltage signal of the output terminal of the differential amplification circuit 4502. For example, the higher the voltage output from the output terminal of the differential amplifier circuit 4502, the higher the flow rate detected by the detection electrode 441 can be determined. It will be appreciated that the electromagnetic flow meter 40 is capable of detecting the flow rate and/or velocity of the liquid flowing from the supply tank 10 into the water pump 20.

In some embodiments, as shown in fig. 3, the electromagnetic flow meter 40 further includes a conditioning circuit 4503, and the conditioning circuit 4503 is connected to the output of the differential amplifying circuit 4502, and converts the voltage signal output from the output of the differential amplifying circuit 4502 into a digital signal.

Illustratively, the conditioning circuit 4503 may include an analog-to-digital converter that converts the voltage output by the differential amplifier circuit 4502 to a digital quantity from which the flow rate and/or flow rate of the fluid may be determined.

In some embodiments, as shown in fig. 3, the amplification circuit 4501 includes a first operational amplifier U1. It will be appreciated that the amplifier circuit 4501 may also be implemented by discrete components, such as semiconductor devices, resistors, and the like. The operation of the amplifier circuit 4501 can be more stable when implemented using an operational amplifier.

Illustratively, as shown in fig. 3, the non-inverting input terminal of the first operational amplifier U1 is connected to the detection electrode 441, and the output terminal of the first operational amplifier U1 is connected to the differential amplifier circuit 4502. The first operational amplifier U1 amplifies the electrode signal of the detection electrode 441, and the amplified signal is input to the differential amplifier circuit 4502 to be differentially amplified.

In some embodiments, as shown in fig. 3, the inverting input of the first operational amplifier U1 is connected to ground through a first resistor R1 and to the output of the amplifying circuit 4501 through a second resistor R2. The amplification factor of the amplifying circuit 4501 can be determined, for example, 6 times by the first resistor R1 and the second resistor R2.

Illustratively, as shown in fig. 3, the inverting input terminal of the first operational amplifier U1 is grounded through a first capacitor C1 and a first resistor R1, and the first capacitor C1 and the first resistor R1 are connected in series.

The first capacitor C1 can isolate the dc level and conduct the ac level, thereby implementing high-pass filtering and improving the amplification effect of the amplifier circuit 4501 on the electrode signal of the detection electrode 441.

Illustratively, as shown in fig. 3, the inverting input terminal of the first operational amplifier U1 is connected to the output terminal of the amplifying circuit 4501 through a second capacitor C2 and a second resistor R2, and the second capacitor C2 and the second resistor R2 are connected in parallel.

The second capacitor C2 can isolate the dc level and conduct the ac level, thereby implementing high-pass filtering and improving the amplification effect of the amplifier circuit 4501 on the electrode signal of the detection electrode 441.

Specifically, the first resistor R1, the second resistor R2, the first capacitor C1, and the second capacitor C2 may be high-precision low-temperature-drift components, so as to improve the precision and stable amplification effect of the amplification circuit 4501. And the amplification factor of the amplifying circuit 4501 is as same as possible.

In some embodiments, as shown in fig. 3, the differential amplifier circuit 4502 includes a second operational amplifier U2, and a non-inverting input terminal and an inverting input terminal of the second operational amplifier U2 are connected to an output terminal of one amplifier circuit 4501, respectively, so that output signals of the two amplifier circuits 4501 can be differentially amplified.

Illustratively, as shown in fig. 3, the non-inverting input terminal and the inverting input terminal of the second operational amplifier U2 are each connected to the corresponding amplifying circuit 4501 through the third capacitor C3.

The third capacitor C3 can isolate the dc level and switch on the ac level to achieve high-pass filtering and prevent unwanted signals from interfering with the differential amplifier 4502.

Illustratively, as shown in fig. 3, a first resistor circuit R3 and a second resistor circuit R4 are connected between the non-inverting input terminal and the inverting input terminal of the second operational amplifier U2, the first resistor circuit R3 and the second resistor circuit R4 are connected in series and have equal resistance, and the connection point of the first resistor circuit R3 and the second resistor circuit R4 is grounded through a fourth capacitor C4. The common mode rejection ratio of the differential amplification circuit 4502 can be improved.

According to the electromagnetic flowmeter, the spraying device and the movable platform provided by the embodiment of the specification, the electrode signals of the detection electrodes are amplified through the amplifying circuits, then the signals amplified by the at least two amplifying circuits are subjected to differential amplification through the differential amplifying circuits, the signals can be converted into higher voltage signals after being subjected to two-stage amplification, the common-mode rejection ratio is higher, and the influence of space power-frequency electromagnetic field interference on the measurement accuracy of the electromagnetic flowmeter can be effectively reduced.

In some embodiments, since the influence of the interference of the space power frequency electromagnetic field on the measurement accuracy of the electromagnetic flowmeter is reduced by the signal amplification circuit, the electromagnetic flowmeter can omit a shielding case, or can adopt a smaller specification, such as a thinner shielding case, so as to reduce the volume and the weight of the electromagnetic flowmeter.

In some embodiments, referring to fig. 4-10, electromagnetic flow meter 40 includes a housing 41, a body support 42, a catheter 43, a detection electrode assembly 44, a signal acquisition assembly 45, and a coil assembly 46.

Referring to fig. 4 to 10, in some embodiments, the main body bracket 42 is connected to the housing 41. At least a portion of the body support 42 extends through the housing 41. The catheter 43 is provided on the main body frame 42. The detection electrode assembly 44 is partially inserted through the liquid guide tube 43 to contact the liquid flowing through the inside of each liquid guide tube 43. The signal acquisition assembly 45 and the coil assembly 46 are both disposed on the main body support 42. The signal collecting assembly 45 is electrically connected with the detection electrode assembly 44 and is used for collecting signals of the detection electrode assembly 44. The coil assembly 46 is used to generate an electromagnetic field.

Specifically, the signal acquisition assembly 45 is disposed within the housing 41.

In some embodiments, the detection electrode assembly 44 and the signal acquisition assembly 45 are both disposed within the housing 41. Illustratively, the housing 41 includes a conductive shell 411, and the housing 41 is grounded to enable the housing 41 to electromagnetically shield the detection electrode assembly 44 and the signal acquisition assembly 45.

Illustratively, the signal amplification circuit 450 may be disposed on the signal acquisition assembly 45, for example, on a circuit board of the signal acquisition assembly 45.

For example, the housing 41 includes a conductive shell 411 made of a first non-metallic material.

The casing 41 can play a role of electromagnetic shielding for the detection electrode assembly 44 and the signal acquisition assembly 45, under the condition that no additional electromagnetic shielding cover is added, the detection electrode assembly 44 and the signal acquisition assembly 45 can be prevented from receiving the interference of external signals by grounding the casing 41, the volume and the weight of the electromagnetic flowmeter 40 can not be increased by the way of realizing electromagnetic shielding by grounding the casing 41, and meanwhile, the cost for arranging the additional electromagnetic shielding cover is also saved. In addition, the housing 41 is the conductive housing 411 made of the first non-metallic material, and the housing 41 can be grounded to achieve electromagnetic shielding without using the metal housing 41, the density of the non-metallic material is generally lower than that of the metal material, and the price of the non-metallic material is generally lower than that of the metal material, so that the housing 41 made of the non-metallic material with conductivity can greatly reduce the weight of the electromagnetic flowmeter 40 and the cost of the electromagnetic flowmeter 40.

In some embodiments, the first non-metallic material includes at least one of carbon nanotubes, graphene, carbon fibers, conductive plastics, and other materials that are electrically conductive and relatively light in weight. The conductive plastic is thermoplastic plastic material doped with metal particles and/or conductive nano particles. In some embodiments, the housing 41 is formed by mixing plastic and conductive filler material. It will be appreciated that the conductive filler material is highly conductive and needs to be present in sufficient quantity to enable contact between the particles of filler material to thereby enable the shell 41 to conduct electricity. Wherein the plastic comprises at least one of polyethylene, polypropylene, polyvinyl chloride, polybutylene, polystyrene, and the like. The conductive filling material comprises at least one of carbon fiber, carbon black, metal conductive powder, metalized glass fiber, graphite fiber and the like.

In some embodiments, referring to fig. 11, the housing 41 includes a shell 411 and a conductive layer 412. The housing 411 is made of a non-conductive plastic, i.e., the housing 411 is made of any plastic that does not have electrical conductivity. The conductive layer 412 is provided on the outer surface of the housing 411. Illustratively, a conductive paint or an electroless metal layer is sprayed on the housing 411, so that all or part of the surface of the housing 411 can be conductive, and the housing 411 can be grounded to achieve electromagnetic shielding.

In some embodiments, body support 42 is a frame made of plastic to further reduce the weight of electromagnetic flow meter 40 and to reduce the cost of electromagnetic flow meter 40. Of course, the material of the body support 42 is not limited to plastic, and other lighter materials may be selected as desired.

In some embodiments, the catheter 43 is made of a second non-metallic material to further reduce the weight of the electromagnetic flow meter 40 and to reduce the cost of the electromagnetic flow meter 40. The second non-metal material may be an insulating plastic, or any other material that is light and has no electrical conductivity. Insulating plastic refers to non-conductive plastic, i.e., plastic that does not have electrical conductivity. The insulating plastic includes at least one of Liquid Crystal Polymer (LCP), Polyphthalamide (PPA), or other non-conductive plastic.

In some embodiments, the catheter 43 is integrally formed with the body mount 42 to reduce assembly steps and improve manufacturing efficiency of the electromagnetic flow meter 40. In other embodiments, the catheter 43 and the main body frame 42 may be provided separately.

Referring to fig. 6 to 10 again, in some embodiments, the detection electrode assembly 44 includes two detection electrodes 441, and the two detection electrodes 441 are respectively disposed through two opposite sides of the catheter 43.

Specifically, the detection ends of the detection electrodes 441 are each capable of passing through the liquid guide tube 43 to be in contact with the liquid flowing through the inside of the liquid guide tube 43, and the detection ends of the two detection electrodes 441 are disposed opposite to each other. In order to enable the two detection electrodes 441 to better generate induced electromotive force, the two detection electrodes 441 are coaxially disposed, i.e., the detection ends of the two detection electrodes 441 are opposite to each other.

In some embodiments, the detecting electrode 441 is made of a third non-metallic material with conductivity, and the electromagnetic flow meter 40 can detect the flow rate and/or the flow velocity of the liquid in the liquid guide tube 43 without using a metal electrode, thereby further effectively reducing the weight of the electromagnetic flow meter 40 and the cost of the electromagnetic flow meter 40. The third non-metallic material includes at least one of carbon nanotubes, graphene, carbon fibers, conductive plastics, and other materials that are electrically conductive and relatively light in weight. Illustratively, the sensing electrode 441 is formed using a mixture of plastic and conductive filler material. It will be appreciated that the conductive filler material has a high conductivity and needs to be present in sufficient quantity to enable contact between the particles between the filler material to enable the detection electrode 441 to be conductive. Wherein the plastic comprises at least one of polyethylene, polypropylene, polyvinyl chloride, polybutylene, polystyrene, and the like. The conductive filling material comprises at least one of carbon fiber, carbon black, metal conductive powder, metalized glass fiber, graphite fiber and the like.

It is understood that when the housing 41 and the detection electrode 441 are both formed by mixing plastic and conductive filling material, the third non-metallic material may be the same as or different from the first non-metallic material, and is not limited herein.

In some embodiments, the detecting electrode 441 has a multi-segment cylindrical structure, and the detecting electrode 441 is in clearance fit with the catheter 43, so as to facilitate the assembly and disassembly of the detecting electrode 441. In order to improve the sealing performance between the detection electrode 441 and the catheter 43, a radial sealing ring is further arranged between the detection electrode 441 and the catheter 43, compared with end face sealing, the end face of the detection electrode 441 in the embodiment of the present disclosure does not need too much pressing force to ensure the sealing effect between the detection electrode 441 and the catheter 43, and prevents liquid in the catheter 43 from flowing from a gap between the detection electrode 441 and the catheter 43 to a gap between the catheter 43 and the housing 41, thereby preventing the signal acquisition assembly 45 or other components from being damaged due to water.

In some embodiments, detection electrode 441 is in intimate contact with signal acquisition assembly 45, and a conductive copper layer is disposed around the electrode hole of signal acquisition assembly 45 to facilitate electrical connection of signal acquisition assembly 45 to detection electrode 441. The signal collection member 45 and the detection electrode 441 may be additionally soldered, thereby improving contact reliability between the signal collection member 45 and the detection electrode 441. In order to improve solderability of the detection electrode 441, the surface of the detection electrode 441 may be plated with tin.

Referring to fig. 6 to 8 again, in some embodiments, the coil assembly 46 includes a coil 461, a core 462 and a fixing frame 463, wherein the coil 461 is wound on the core 462. The iron core 462 is disposed on the fixing frame 463 for restricting the magnetic field direction and reducing the magnetic flux leakage. The fixing frame 463 is attached to the main body frame 42 or the catheter 43. Any suitable connection between the fixing frame 463 and the main body frame 42 or between the fixing frame 463 and the catheter 43 may be used, as desired, for example, by integral molding, or by detachable connection via screws, bolts, snaps, etc. Alternatively, the axial direction of the detection electrode 441 is perpendicular to the axial direction of the coil assembly 46, that is, the axial direction of the detection electrode 441 is perpendicular to the length extension direction of the iron core 462, so that the detection electrode 441 better generates induced electromotive force.

The number of coil assemblies 46 can be set according to practical requirements, for example, one, two or more coil assemblies can be designed, as long as the magnetic field can be generated to generate the induced electromotive force for detection in the catheter 43. When the number of the liquid guide pipes 43 is multiple and the number of the coil assemblies 46 is multiple, the multiple coil assemblies 46 are symmetrically distributed in the middle of each liquid guide pipe 43, so that the magnetic field intensity at the target position in each liquid guide pipe 43 is basically consistent, and the flow detection precision is ensured. The target location is the location in each of the catheters 43 where the sensing end or measuring plane of the electrode assembly 44 is located.

Referring to fig. 6 to 8 again, the number of the liquid guiding tubes 43 is four, and the liquid guiding tubes 43a, 43b, 43c, and 43d are arranged in parallel, and the liquid flowing direction is from top to bottom. The two detection electrodes 441 are disposed in the front-rear direction. The number of the coil assemblies 46 is two, and the coil assemblies are symmetrically arranged in the middle of the four liquid guide pipes 43, namely between the liquid guide pipes 43a and 43b and between the liquid guide pipes 43c and 43d, and the magnetic field direction is in the left-right direction and is perpendicular to the liquid flow. The ions of the liquid flowing through the liquid guide tube 43 are deflected by the electromagnetic field to generate an electromotive force in the front-rear direction, and the magnitude of the electromotive force can be detected by the detection electrode assembly 44. This electromagnetic flowmeter 40 adopts electromagnetic induction's detection principle, and the electromagnetic field, catheter 43 and two detection electrode 441 arrange the three and be the orthogonal distribution, and electromotive force and magnetic field intensity are all in direct proportion with water velocity, thereby the size of the backward thrust rivers flow through detection electrode 441 detection voltage.

Illustratively, the number of the detection electrode assemblies 44 is the same as that of the liquid guide tubes 43, and each liquid guide tube 43 is provided with the detection electrode assembly 44 correspondingly. The number of coil assemblies 46 may be the same as or different from that of the catheters 43, and is not limited herein. Alternatively, when the number of the coil assemblies 46 is plural, the plural coil assemblies 46 are coaxially arranged so that the detection electrode 441 better generates induced electromotive force.

Referring to fig. 6, 8-10, in some embodiments, electromagnetic flow meter 40 further includes a control board 47. The control board 47 is electrically connected to the signal acquisition assembly 45 for acquiring the flow rate and/or velocity of the liquid flowing through the liquid guide tube 43 according to the signal acquired by the signal acquisition assembly 45. The control board 47 may be disposed at both sides of the body frame 42 opposite to the coil assembly 46.

In some embodiments, the housing 41 may be grounded by directly contacting the signal acquisition assembly 45, or the housing 41 may be grounded by electrically connecting the housing 41 and the signal acquisition assembly 45 through a ground connector, which is not limited herein, and of course, the housing 41 may also be grounded by directly contacting the control board 47, or the housing 41 may be grounded by electrically connecting the housing 41 and the control board 47 through a ground connector, which is not limited herein.

Referring to fig. 6, 7, 9 and 10, in order to improve the flow rate detection accuracy, the electromagnetic flowmeter 40 further includes a first ground electrode 484 and a second ground electrode 485, and the first ground electrode 484 and the second ground electrode 485 can partially penetrate through the liquid guide tube 43 to contact the liquid flowing through the liquid guide tube 43. The first grounding electrode 484 and the second grounding electrode 485 are both electrically connected with the signal acquisition assembly 45 or the control panel 47, so that the liquid potential in the liquid guide tube 43 is zero, and the two detection electrodes 441 both detect electromotive force by using the zero potential of the liquid as a reference, thereby improving the flow detection precision.

In some embodiments, first ground electrode 484 and second ground electrode 485 may be positioned at any suitable location as desired, so long as detection electrode assembly 44 is positioned between first ground electrode 484 and second ground electrode 485. Specifically, the first ground electrode 484, the detection electrode assembly 44, and the second ground electrode 485 are sequentially provided at intervals in the extending direction of the catheter 43. More specifically, a first ground electrode 484 and a second ground electrode 485 are provided at the inlet end and the outlet end of the liquid guide tube 43, respectively.

Referring to fig. 6 and 10, in some embodiments, electromagnetic flow meter 40 further includes an electrical connector 494, wherein electrical connector 494 is configured to be connected to an external power source to electrically operate electromagnetic flow meter 40.

It should also be understood that the term "and/or" as used in this specification and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

The above description is only for the specific embodiments of the present disclosure, but the scope of the present disclosure is not limited thereto, and any person skilled in the art can easily conceive various equivalent modifications or substitutions within the technical scope of the present disclosure, and these modifications or substitutions should be covered within the scope of the present disclosure. Therefore, the protection scope of the present specification shall be subject to the protection scope of the claims.

Claims (15)

1. An electromagnetic flowmeter, comprising a housing, at least two sensing electrodes, and a signal amplification circuit within the housing;

wherein the signal amplification circuit includes:

the input ends of the amplifying circuits are respectively connected to one detection electrode, and the amplifying circuits amplify electrode signals of the detection electrodes;

at least two input ends of the differential amplification circuit are respectively connected to the output end of one amplification circuit, and the output end of the differential amplification circuit outputs a voltage signal.

2. The electromagnetic flowmeter of claim 1 wherein the amplification circuit comprises a first operational amplifier.

3. The electromagnetic flowmeter of claim 2 wherein a non-inverting input of the first operational amplifier is coupled to the sensing electrode and an output of the first operational amplifier is coupled to the differential amplifier circuit.

4. The electromagnetic flowmeter of claim 3 wherein the inverting input of the first operational amplifier is connected to ground through a first resistor and to the output of the amplifying circuit through a second resistor.

5. The electromagnetic flowmeter of claim 4 wherein said inverting input of said first operational amplifier is connected to ground through a first capacitor and said first resistor, said first capacitor and said first resistor being connected in series.

6. The electromagnetic flowmeter of claim 4 or 5 wherein the inverting input of the first operational amplifier is connected to the output of the amplifying circuit through a second capacitor and a second resistor, the second capacitor and the second resistor being connected in parallel.

7. An electromagnetic flowmeter according to any of claims 1-5 wherein the amplification of at least two of said amplification circuits is the same.

8. An electromagnetic flowmeter according to any of claims 1-5 wherein a polarizing voltage is generated between a sensing electrode of said electromagnetic flowmeter and a conductive fluid, said polarizing voltage being amplified by said amplifying circuit.

9. An electromagnetic flowmeter according to any of claims 1-5 wherein said differential amplifier circuit comprises a second operational amplifier having its non-inverting input connected to the output of one of said amplifier circuits.

10. The electromagnetic flowmeter of claim 9 wherein the non-inverting input and the inverting input of the second operational amplifier are each connected to a corresponding amplification circuit through a third capacitor.

11. The electromagnetic flow meter according to claim 9, wherein a first resistance circuit and a second resistance circuit are connected between the non-inverting input terminal and the inverting input terminal of the second operational amplifier, the first resistance circuit and the second resistance circuit are connected in series and have equal resistance values, and a connection point of the first resistance circuit and the second resistance circuit is grounded through a fourth capacitor.

12. The electromagnetic flowmeter of any of claims 1-5 further comprising a conditioning circuit coupled to the output of the differential amplifier circuit to convert the voltage signal output by the output of the differential amplifier circuit to a digital signal.

13. A spraying device, comprising:

a liquid supply tank;

the water pump is used for pumping liquid from the liquid supply tank;

the spray head is communicated with the water pump, and the water pump conveys liquid to the spray head and sprays the liquid out through the spray head;

the electromagnetic flow meter according to any of claims 1-12, being in communication between the supply tank and the water pump, the electromagnetic flow meter being adapted to detect the flow and/or velocity of the liquid flowing from the supply tank into the water pump.

14. A movable platform, comprising:

a movable body;

the spray device of claim 13 mounted on said movable body.

15. The movable platform of claim 14, wherein the movable platform comprises:

at least one of an agricultural unmanned aerial vehicle, an agricultural spray vehicle and a manpower spraying device.

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