Flow sensor

Abstract

The utility model provides a flow sensor. The flow sensor comprises a first fan blade, an inductance coil and a pulse output circuit. Wherein the first fan blade is provided with more than two first blades which are circumferentially arranged at intervals, and the first fan blade rotates under the driving of fluid, so that the first blades and the inductance coil can be dynamically and alternately close to or far away from each other, and the inductance value of the inductance coil is changed. And the pulse output circuit is electrically connected with the inductance coil. Compared with an existing condition that a first pulse signal and a second pulse signal are respectively output when two adjacent first blades sequentially cut a magnetic induction line by utilizing a Hall effect principle, the first pulse signal can be output when the first blades are close to an inductance coil; and when the preset position (such as the middle position of the two adjacent blades) between the two adjacent first blades is close to the inductance coil, the second pulse signal is output, so that the number of pulse signals output in unit time can be multiplied, and the measurement sensitivity is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of flow sensors, and particularly relates to a flow sensor. BACKGROUND

[0002] A flow sensor is a kind of detection instrument for detecting the flow parameter of a medium such as liquid or gas and converting it into other forms of signals for output. The flow sensor has many advantages such as small volume, light weight, intuitive and clear reading, high reliability, and no pressure loss, and therefore has been widely applied in many fields such as environmental monitoring, safety protection, medical health, and trade settlement.

[0003] In the related art, a flow sensor can detect the rotating speed of turbine blades by using the Hall effect, so as to indirectly measure the flow of fluid. Specifically, when fluid flows, the internal turbine is driven to rotate, the magnetic blades on the turbine cut the magnetic induction lines, a changing magnetic field is generated, and then the Hall element generates a corresponding Hall voltage. In this scheme, the adjacent blades generally have alternating magnetic poles (for example, the north and south poles are arranged alternately), so that the two adjacent blades can output a first pulse signal and a second pulse signal, respectively, when they cut the magnetic induction lines in turn. For example, if the number of turbine blades is 4, only 4 pulse signals are output when the turbine blades rotate one circle. When the fluid flow changes slightly, it cannot quickly respond to the change of the flow, and the measurement sensitivity is not enough. SUMMARY

[0004] One purpose of the present application is to provide a flow sensor which detects the flow by using the principle that the first blades are close to or away from the inductor coil, so that the inductance of the inductor coil changes. The first pulse signal can be output when the blades are close to the inductor coil, and the second pulse signal can be output when the preset position (such as the middle position of the adjacent two blades) between the adjacent two blades is close to the inductor coil. Therefore, the number of pulse signals output per unit time can be increased, and the measurement sensitivity can be improved.

[0005] To solve the above technical problems, the present application adopts the following technical solutions:

[0006] The technical solution of the first aspect of the present application provides a flow sensor, which comprises:

[0007] A first fan blade, the first fan blade has two or more first blades arranged in a circumferential direction;

[0008] An inductor coil, wherein the first fan blade is used to rotate under the driving of fluid, so that the first blades dynamically alternately approach and move away from the inductor coil, so that the inductance of the inductor coil changes;

[0009] The pulse output circuit is electrically connected with the inductor coil, and is configured to output alternating first pulse signals and second pulse signals, wherein the first pulse signals are signals corresponding to the output when the first vane is close to the inductor coil, and the second pulse signals are signals corresponding to the output when a preset position between two adjacent first vanes is close to the inductor coil.

[0010] In an embodiment of the present application, the pulse output circuit comprises a conversion circuit, a signal amplification circuit and a voltage comparison circuit; wherein the conversion circuit is electrically connected with the inductor coil, the signal amplification circuit is electrically connected with the conversion circuit, and the voltage comparison circuit is electrically connected with the signal amplification circuit.

[0011] The conversion circuit is configured to convert into different pulse signals based on the change of the inductance of the inductor coil.

[0012] The signal amplification circuit is configured to amplify the different pulse signals.

[0013] The voltage comparison circuit is configured to compare the amplified pulse signals with a reference voltage to output alternating first pulse signals and second pulse signals.

[0014] In an embodiment of the present application, at least a part of each first vane is provided as a magnetic core part, and the magnetic core part is made of soft magnetic material. Correspondingly, the inductor coil comprises a wire coil, and the end faces of the wire coil at the two axial ends are respectively a first side and a second side. The first side is configured as a spiral coil. The wire coil is arranged at one side of the first vane in the radial direction, and the first side is spaced apart from the first vane. The first vane is used to rotate relative to the wire coil under the drive of the fluid, so that the first vane and the wire coil dynamically and alternately approach and move away from each other.

[0015] In an embodiment of the present application, each first vane is provided as the magnetic core part as a whole; or a part of each first vane is provided as the magnetic core part, wherein the first vane comprises a vane body part and the magnetic core part, and the magnetic core part is fixed to the vane body part.

[0016] In an embodiment of the present application, at least a part of each first vane is provided as a conductive part; correspondingly, the inductor coil can generate mutual inductance with at least a part of the first vane in a charged state.

[0017] In an embodiment of the present application, the first vane comprises a vane body part and the conductive part, the vane body part is an insulator, and the conductive part is embedded in the vane body part.

[0018] In one embodiment of the present application, the conductive part is a conductive non-magnetic material.

[0019] In one embodiment of the present application, the flow sensor further comprises a frequency reduction circuit, which is electrically connected with the pulse output circuit, and is configured to receive the pulse signal output by the pulse output circuit and perform frequency reduction processing to reduce the frequency of the pulse signal.

[0020] In one embodiment of the present application, the flow sensor further comprises a frequency output circuit, which is electrically connected with the pulse output circuit, and is configured to output the frequency of the pulse signal based on the first pulse signal and the second pulse signal output by the pulse output circuit.

[0021] In the technical scheme provided in the embodiments of the present application, the flow sensor comprises a first fan blade, an inductor coil and a pulse output circuit. The first fan blade has two or more first blades arranged in a circumferential direction at intervals. The first fan blade rotates under the driving of the fluid, and can make the first blades dynamically alternately approach and move away from the inductor coil, so as to change the inductance of the inductor coil. The pulse output circuit is electrically connected with the inductor coil, so that the pulse output circuit can output the first pulse signal and the second pulse signal alternately based on the change of the inductance of the inductor coil. The first pulse signal is the signal corresponding to the output when the first blade approaches the inductor coil, and the second pulse signal is the signal corresponding to the output when the preset position between the adjacent two first blades approaches the inductor coil. Compared with the case that the first pulse signal and the second pulse signal are respectively output when the adjacent two first blades cut the magnetic induction line in turn according to the principle of Hall effect, the present application can output the first pulse signal when the first blade approaches the inductor coil, and output the second pulse signal when the preset position (such as the middle position of the adjacent two blades) between the adjacent two first blades approaches the inductor coil according to the principle that the inductance of the inductor coil changes when the first blade approaches or moves away from the inductor coil. Therefore, the number of pulse signals output per unit time can be doubled, and the measurement sensitivity can be improved.

[0022] It should be understood that the above general description and the following detailed description are only exemplary and cannot limit the present application. BRIEF DESCRIPTION OF DRAWINGS

[0023] The above and other objects, features and advantages of the present application will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

[0024] Figure 1 is an exploded structural schematic view of the flow sensor of Embodiment One of the present application.

[0025] Figure 2is a partial sectional structure schematic view of the flow sensor of the embodiment one of the present application.

[0026] Figure 3 is Figure 2 is an enlarged structure schematic view of A part shown in

[0027] Figure 4 is a side structure schematic view of the flow sensor of the embodiment one of the present application.

[0028] Figure 5 is Figure 4 is a sectional structure schematic view of B-B part shown in

[0029] Figure 6 is a partial sectional structure schematic view of the flow sensor of the embodiment one of the present application.

[0030] Figure 7 is a structure schematic view of the first vane relative to the wire disc in the first position in the embodiment one of the present application.

[0031] Figure 8 is Figure 7 is a side structure schematic view of the first vane and the wire disc shown in

[0032] Figure 9 is a structure schematic view of the first vane relative to the wire disc in the second position in the embodiment one of the present application.

[0033] Figure 10 is a structure schematic block view of the pulse output circuit in the embodiment one of the present application.

[0034] The reference signs are as follows:

[0035] 1, first vane; 11, first blade; 111, first inclined surface; 112, second inclined surface; 12, first center part; 13, shaft body;

[0036] 2, inductance coil; 21, wire disc; 22, wire;

[0037] 3, first shell; 31, side wall; 311, groove part; 3111, bottom wall; 32, stop step; 33, fence part; 34, first liquid inlet; 35, second liquid outlet;

[0038] 4, flow guide member; 41, flow guide blade; 42, flow guide member center part; 43, connecting groove; 44, ring body;

[0039] 5, rotor cover body; 51, notch;

[0040] 6, support; 61, shaft hole;

[0041] 7, outer cover;

[0042] 8, circuit board; 81, connection terminal; 82, pulse output circuit; 821, conversion circuit; 822, signal amplification circuit; 823, voltage comparison circuit. DETAILED DESCRIPTION

[0043] While the application can be susceptible to various modifications and alternative forms, only some specific embodiments have been shown by way of example in the drawings and will be described in detail herein. It should be understood however that the description intended to be illustrative only and not restrictive of the application as claimed.

[0044] Thus, one feature that is described in the specification is used to illustrate one feature of an embodiment of the application and not that every embodiment of the application must have that described feature. Furthermore, it should be noted that the specification describes many features. Although certain features can be combined together to show a possible system design, these features can also be used in other combinations that are not explicitly described. Thus, the described combinations are not intended to be limiting unless otherwise specified.

[0045] In the embodiments shown in the drawings, the indications of direction are used to explain the structure and movement of various elements of the application are not absolute but relative. These indications are appropriate when the elements are in the position shown in the drawings. If the position of the elements is changed, the indications of direction are changed accordingly.

[0046] Example embodiments will now be described more fully with reference to the accompanying drawings. Example embodiments, however, can be implemented in many different forms and should not be construed as limited to the examples set forth herein; rather, these example embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the inventive concept to those skilled in the art. The accompanying drawings are included to provide a further understanding of the application and are incorporated into and constitute a part of this specification. The drawings are not intended to be to scale with one another. Like reference numerals designate corresponding parts throughout the several views. Descriptions of the same or similar elements are not repeated in descriptions of the several figures.

[0047] In the related art, a flow sensor can detect the rotating speed of turbine blades by using the Hall effect, thereby indirectly measuring the flow of fluid. Specifically, when fluid flows, it drives the internal turbine to rotate, and the magnetic blades on the turbine cut the magnetic induction lines to generate a changing magnetic field, which in turn causes the Hall element to generate a corresponding Hall voltage. In this scheme, adjacent blades generally have alternating magnetic poles (for example, north and south poles are arranged alternately), so that when two adjacent blades cut the magnetic induction lines in turn, they can output first and second pulse signals, respectively. For example, if the number of turbine blades is 4, only 4 pulse signals are output when the turbine blades rotate one revolution. When the fluid flow changes slightly, it will not be able to respond quickly to the change in flow, and the measurement sensitivity is not enough.

[0048] Based on this, the embodiment of the present application proposes a flow sensor. The flow sensor utilizes the principle that the inductance of the inductance coil changes when the first blade is close to or far away from the inductance coil to detect the flow. The first pulse signal can be output when the first blade is close to the inductance coil, and the second pulse signal can be output when the preset position between the adjacent two first blades is close to the inductance coil. Thus, the number of pulse signals output per unit time can be increased, and the measurement sensitivity can be improved.

[0049] Specifically, the flow sensor includes a first fan blade, an inductance coil, and a pulse output circuit. The first fan blade has two or more first blades arranged at a circumferential interval. The first fan blade is used to rotate under the driving of the fluid, so that the first blades dynamically and alternately close to and away from the inductance coil, so that the inductance of the inductance coil changes. The pulse output circuit is electrically connected with the inductance coil, and the pulse output circuit is configured to output alternately changing first pulse signals and second pulse signals. The first pulse signal is a signal corresponding to the output when the first blade is close to the inductance coil, and the second pulse signal is a signal corresponding to the output when the preset position between the adjacent two first blades is close to the inductance coil. In the embodiment of the present application, compared with the case that the first pulse signal and the second pulse signal are respectively output when the adjacent two first blades cut the magnetic induction line in turn according to the principle of the Hall effect, the present application utilizes the principle that the inductance of the inductance coil changes when the first blade is close to or far away from the inductance coil, and the first pulse signal can be output when the first blade is close to the inductance coil, and the second pulse signal can be output when the preset position between the adjacent two first blades is close to the inductance coil. Thus, the number of pulse signals output per unit time can be doubled, and the measurement sensitivity can be improved. For example, for the flow sensor for flow measurement according to the principle of the Hall effect, if the first fan blade has four first blades arranged at a circumferential interval, the first fan blade can output four pulse signals per revolution. However, the flow sensor provided by the embodiment of the present application utilizes the principle that the inductance of the inductance coil changes when the first blade is close to or far away from the inductance coil to measure the flow, and if the first fan blade has four first blades arranged at a circumferential interval, the first fan blade can output eight pulse signals per revolution. It can be seen that the flow sensor provided by the embodiment of the present application can double the number of pulse signals output per unit time. Since the number of pulses output per unit time and the cumulative number of pulses output can calculate the instantaneous flow and the cumulative flow, increasing the number of output pulse signals means that more pulses are generated in the same time, which can improve the response speed and the measurement accuracy of the flow sensor to the flow, that is, the measurement sensitivity can be improved.

[0050] Embodiment one

[0051] See Figure 1The embodiment one of the present application provides a flow sensor for detecting the flow of fluid.

[0052] For example, the flow sensor comprises a first vane 1, an inductor coil 2, a first housing 3, a flow guide 4, a rotor cover 5, a bracket 6, an outer cover 7, a circuit board 8, etc.

[0053] The first vane 1 can also be referred to as a rotor in the art, and the first vane 1 has two or more first blades 11 arranged circumferentially at intervals, at least a part of each first blade 11 is arranged as a magnetic core part, and the magnetic core part is a soft magnetic material.

[0054] The inductor coil 2 comprises a coil 21, an end face of an axial one end of the coil 21 is a first side face, and an end face of an axial other end of the coil 21 is a second side face, and the first side face is configured as a planar spiral coil.

[0055] Optionally, the coil 21 of the electromagnetic coil can be configured to have a certain axial thickness, and the axial direction of the coil 21 can be the thickness direction of the coil 21.

[0056] Optionally, the first side face can be configured as a planar spiral coil. For example, the end face of the axial one end of the coil 21 is configured as a planar spiral coil, or the coil 21 can be a planar spiral coil as a whole.

[0057] For example, the coil 21 is a structure formed by winding a wire (such as a flat wire or a circular wire, etc.), and the end face of the axial one end of the coil 21 is a planar spiral coil. For example, the coil 21 is a single-layer planar spiral coil as a whole, or the coil 21 is a multi-layer planar spiral coil arranged axially in a superposed manner, each layer of the planar spiral coil is a planar structure formed by spirally winding the wire from the center to the outside (or from the outside to the inside). Alternatively, the coil 21 is a shape formed by sequentially nesting a plurality of cylindrical coils inward (or outward), and the end portions of the plurality of cylindrical coils are substantially located in the same plane, thereby configuring the feature that the end face of the axial one end of the coil 21 is a planar spiral coil.

[0058] It can be understood that in the art, the planar spiral coil can also be referred to as a planar spiral type coil or a planar solenoid or a flat inductor. It should be noted that the planar in the planar spiral, or the flat in the planar spiral coil / flat inductor, does not specifically mean that the surface of each layer of the planar spiral coil is an absolute plane, but should be understood in an open manner that each layer of the planar spiral coil of the present application can be arranged as a plane or a curved surface (such as a concave surface or a convex surface) with a certain arc according to the needs, or can appropriately contain the reasonable deviation that each layer of the planar spiral coil is manufactured to be a curved surface (such as a concave surface or a convex surface) with a slight arc.

[0059] Of course, the present application is not limited thereto, in other embodiments, the first side can be configured as a slightly concave spiral coil, or the first side can be configured as a slightly convex spiral coil.

[0060] The use of the coil 21 comprising a spiral coil enables the coil 21 to more sensitively sense the magnetic core portion of the first vane when the first vane is close to the coil 21. In this way, as the first vane 11 approaches or moves away from the coil 21, the coil 21 more sensitively responds to the change in the size of the inductance formed, thereby enabling the change frequency of the inductance of the coil 21 to more truly and sensitively reflect the rotational speed of the first vane 1, so as to more accurately express the flow rate of the fluid.

[0061] The coil 21 is arranged on the radial side of the first vane 1, and the two sides of the coil 21 in the axial direction correspondingly form a first side and a second side. The first side of the coil 21 is spaced apart from the first vane 1, and correspondingly, the second side of the coil 21 is arranged opposite to the first vane 1. The first vane 1 is used to rotate relative to the coil 21 under the drive of the fluid, so that the first vane 11 and the coil 21 dynamically alternately approach and move away from each other. Correspondingly, the magnetic core portion of the first vane 11 and the coil 21 dynamically alternately approach and move away from each other. It can be understood that when the first vane 11 and the coil 21 relatively approach each other, the coil 21 responds to the approach of the magnetic core portion and thereby generates a relatively large inductance, and when the first vane 11 and the coil 21 relatively move away from each other, the coil 21 responds to the moving away of the magnetic core portion and thereby generates a relatively small inductance or no inductance. In this way, by dynamically alternately approaching and moving away from each other between the first vane 11 and the coil 21, the coil 21 of the inductance coil 2 induces an alternating change in the size of the inductance, so as to reflect the rotational speed of the first vane 1 by using the change in the size of the inductance, and further reflect the flow rate of the fluid used to drive the first vane 1 to rotate, thereby achieving the purpose of flow rate detection.

[0062] In the inductance sensor, the first blade 11 is provided with a magnetic core part, the magnetic core part is made of soft magnetic material, the end surface of the axial one end of the coil 21 of the inductance coil 2 is provided with a spiral coil, and the coil 21 is located at the radial side of the first blade 1 and is spaced apart from the first blade 1. By using the spiral coil to induct the magnetic core part of the soft magnetic material, when the first blade 11 of the first blade 1 approaches the coil 21, the coil 21 can more sensitively induct the magnetic core part of the first blade 11 to form an inductance change. Correspondingly, when the first blade 1 rotates relative to the coil 21 under the driving of the fluid, the magnetic core part of the first blade 11 and the coil 21 dynamically alternately approach and move away from each other. In this way, the coil 21 responds to the approach and movement away of the first blade 11 to more sensitively form an alternating change of the inductance. Therefore, the rotation speed of the first blade 1 can be more sensitively identified by the frequency of the inductance change, and the fluid flow rate can be more accurately identified by the rotation speed of the first blade 1, so as to achieve the purpose of more accurate and more sensitive flow detection. Moreover, since the magnetic core part is made of soft magnetic material, there is no magnetic field around the soft magnetic material. Therefore, while achieving the above-mentioned purpose of flow detection by mutual inductance between the magnetic core part and the coil 21, the problem of the first blade 1 adsorbing iron filings in the fluid is avoided, the risk of the first blade 1 being stuck is greatly reduced, and the reliability of the product for long-term use is better ensured. Moreover, compared with the scheme using a Hall element, since the Hall element is cancelled, the cost of the product is reduced, the problem of high failure rate caused by high damage rate of the Hall element is avoided, and the product is more conducive to promotion.

[0063] When the first side surface of the coil 21 is a planar spiral coil, the inductance sensor has higher sensitivity to the approach and movement away of the magnetic core part of the first blade.

[0064] The soft magnetic material can be further selected from a soft magnetic poor conductor material, such as a soft magnetic non-conductive material or a soft magnetic non-metallic material (such as a ceramic material) or a soft magnetic high-resistivity alloy material (such as an iron-aluminum alloy, an iron-silicon alloy, an iron-silicon-aluminum alloy, etc.). The soft magnetic material itself has excellent magnetic permeability, so that the inductance of the coil can be affected by approaching and moving away from the coil, such as increasing the inductance of the coil by approaching the coil and reducing the inductance of the coil by moving away from the coil. The soft magnetic poor conductor material has high resistivity in addition to excellent magnetic permeability, which can further prevent the magnetic core part from generating eddy current loss under the influence of the magnetic field of the coil.

[0065] For example, the magnetic core part is a soft magnetic ferrite (also known as a non-metallic ferrimagnetic soft magnetic material), and it can be understood that the soft magnetic material has no magnetic field around it, so it will not adsorb iron filings in the fluid. Ferrite can be a "functional ceramic material" sintered by mixing iron oxide with other metal oxides together, which has good magnetic conductivity and small residual magnetism after the external current is removed compared with general metals. For a more detailed example, the soft magnetic ferrite can be specifically manganese-zinc ferrite, nickel-zinc ferrite, barium-zinc ferrite, magnesium-zinc ferrite, etc. Of course, in other embodiments, the magnetic core part can be other soft magnetic materials other than soft magnetic ferrite, such as nanomaterials containing FeCoNiCrAL alloy and / or NiZnCuFe oxide, ceramic materials, amorphous soft magnetic alloys, etc.

[0066] Optionally, in combination with Figure 1 and Figure 7 It can be understood that the first fan blade 1 specifically includes a first central part 12 and two or more first blades 11, each first blade 11 extending radially outward from the edge of the first central part 12. The first central part 12 and the two or more first blades 11 are optionally provided in an integrated structure, and both are made of soft magnetic material, that is, the first fan blade 1 as a whole is a magnetic core part of soft magnetic material. In this way, the first central part 12 and the two or more first blades 11 are integrally formed, which is more efficient in processing, and the first blades 11 are less likely to break or come off, and the product has better reliability, and each first blade 11 itself as a whole is a magnetic core part, so it is easier to ensure that the minimum distance between the magnetic core part of each first blade 11 and the coil 21 is substantially uniform among the plurality of first blades 11 of the first fan blade 1. Therefore, when each first blade 11 is at the minimum distance from the coil 21, the inductance amplitude on the coil 21 fluctuates little, and the identification of the inductance frequency can be more accurate.

[0067] Optionally, in combination with Figure 1 and Figure 7 It can be understood that each first blade 11 of the first fan blade 1 is radially distributed outward relative to the center of the first fan blade 1, that is, each first blade 11 extends linearly radially outward; and the root of each first blade 11 is arranged parallel to the axial direction of the first fan blade 1, that is, the junction position of each first blade 11 and the first central part 12 is arranged in a straight line substantially parallel to the axial direction of the first fan blade 1. Through the first fan blade 1 of this shape, by rotating the first fan blade 1 relative to the coil 21, the first blade 11 and the coil 21 form a more distinct state switching between the corresponding state (as shown in Figure 7 and the misalignment state (as shown in Figure 9 ), that is, the first blade 11 and the coil 21 switch from the corresponding state shown in Figure 7 to the misalignment state shown in Figure 9In the misalignment state shown, the transition angle of the part of the first vane 11 corresponding to the wire coil 21 and the part of the first vane 11 misaligned with the wire coil 21 is smaller, and correspondingly, the time length of the intermediate transition state of the part of the first vane 11 corresponding to the wire coil 21 and the part of the first vane 11 misaligned with the wire coil 21 is shorter, so that the size of the inductance on the wire coil 21 alternately changes more clearly, so as to more accurately identify the change frequency of the inductance, and further improve the detection accuracy of the fluid flow. Of course, the present application is not limited thereto, and in other embodiments, the first vane 11 can be provided with a certain degree of curvature in the circumferential direction, and / or the root of the first vane 11 (i.e. the intersection position of the first vane 11 and the first central portion 12) can be provided with a certain degree of helicity in the axial direction of the first central portion 12.

[0068] Optionally, as shown, Figure 1 The first fan leaf 1 further comprises a shaft body 13, which is connected with the first central portion 12 and protrudes towards both sides in the axial direction relative to the first central portion 12. The shaft body 13 is used for the rotational connection of the first fan leaf 1. Further optionally, the shaft body 13 and the first central portion 12 are two components of different materials, for example, the shaft body 13 can be a plastic shaft, and the first central portion 12 is provided with an axial through shaft hole, and the shaft body 13 is inserted into the shaft hole of the first central portion 12 for connection, and the plastic shaft is used for the rotational connection of the first fan leaf 1, which can be beneficial to reduce the rotational friction of the first fan leaf 1, thereby further improving the accuracy of the product in detecting the fluid flow. Still further optionally, the shaft body 13 can be provided in a two-segment structure, for example, the shaft body 13 is divided into a first shaft segment and a second shaft segment, and each of the first shaft segment and the second shaft segment is provided with a shaft shoulder stop piece, wherein one end of the first shaft segment is rotatably connected, for example, the one end of the first shaft segment is inserted into the connecting groove 43 of the flow guide 4, one end of the second shaft segment is rotatably connected, for example, the one end of the second shaft segment is inserted into the shaft hole 61 of the bracket 6, and the other end of the first shaft segment and the other end of the second shaft segment are inserted into the shaft hole of the first central portion 12 from both ends of the shaft hole of the first central portion 12, wherein the shaft hole of the first central portion 12 is provided as a polygonal hole, and correspondingly, the part of the first shaft segment inserted into the first central portion 12 and the part of the second shaft segment inserted into the first central portion 12 are provided as polygonal surface profiles, so that the first shaft segment and the second shaft segment are rotated together with the first fan leaf 1. The two of the first shaft segment and the second shaft segment are provided with a protruding column at one end close to each other, and the other is provided with a recess, so that the one end of the first shaft segment and the second shaft segment close to each other is inserted and matched. The first fan leaf 1 is located between the shaft shoulder stop piece of the first shaft segment and the shaft shoulder stop piece of the second shaft segment, thereby achieving the axial limiting of the first fan leaf 1 at both axial ends. Of course, the present application is not limited thereto, and in other embodiments, the shaft body 13 can also be made of soft magnetic material and integrated with the first central portion 12, or in other embodiments, the shaft body 13 can also be a metal shaft.

[0069] Optionally, the wire coil 21 is wound by self-adhesive enameled wire. It can be understood that the surface of the self-adhesive enameled wire has a glue layer, which melts when exposed to high temperature, which is conducive to the adhesion of adjacent two turns of the wire coil 21, and also conducive to the adhesion and fixation of the whole wire coil 21, and the fixation and processing of the wire coil 21 are more convenient.

[0070] Optionally, as shown in Figure 1 the surface of the wire coil 21 is set to have a certain length and width. Of course, the present application is not limited thereto, and in other embodiments, the surface of the wire coil 21 can be set to be elliptical, circular, etc.

[0071] Optionally, the wire coil 21 has a through hole in the center, and the wires of the wire coil 21 are spirally wound around the periphery of the through hole, and the wall thickness direction of the wire coil 21 is consistent with the penetration direction of the through hole. In this way, the same length of wire can achieve a larger surface area of the wire coil 21, to further improve the detection accuracy of the flow of the fluid. Of course, the present application is not limited thereto, and in other embodiments, the center of the wire coil 21 can also not be provided with a through hole, and the wire coil 21 as a whole is a solid structure.

[0072] It can be understood that the inductor coil 2 generates a change in inductance that increases in response to the approach between the first blade 11 and the wire coil 21, and generates a change in inductance that decreases in response to the separation between the first blade 11 and the wire coil 21. Optionally, the flow sensor is configured such that during the rotation of the first fan blade 1 relative to the wire coil 21, the maximum inductance L1 of the inductor coil 2 and the minimum inductance L2 of the inductor coil 2 satisfy: 0.5%≤(L1-L2) / L1≤10%. In this way, the inductance change frequency of the wire coil 21 can be more accurately identified, so that the flow detection accuracy of the flow sensor is higher.

[0073] Further optionally, the ratio of the absolute value of the difference between L1 and L2 to L1 is greater than or equal to 1% and less than or equal to 10%. While achieving more accurate and sensitive identification of the inductance change frequency of the wire coil 21, the size of the wire coil 21 can also be better considered.

[0074] Optionally, the distance between the first side surface and one of the first vanes 11 is less than or equal to 5 mm and greater than or equal to 0.5 mm. The distance between the first side surface and one of the first vanes 11 is less than or equal to 5 mm, so that the magnetic core of the first vane 11 can be more sensitive to the mutual inductance with the coil 21 when the first vane 11 is closest to the coil 21, thereby more obviously increasing the inductance of the coil 21, so that the change range of the inductance of the coil 21 is larger, and the frequency of the change of the inductance of the coil 21 is more accurately identified, thereby more accurately measuring the flow rate. The distance between the first side surface and one of the first vanes 11 is greater than or equal to 0.5 mm, so that the distance between the first vane 11 and the coil 21 can be more easily configured, and the cost of the product is reduced while ensuring the smooth rotation of the first vane 1.

[0075] Optionally, the rotation of the first vane 1 relative to the coil 21 includes a first position and a second position; as shown in Figure 7 and Figure 8 When the first vane 1 rotates to the first position, the smallest distance is formed between the coil 21 and one of the first vanes 11, and at this time, the inductance of the coil 21 is the largest because the distance between the magnetic core of the first vane 11 and the coil 21 is the smallest; as shown in Figure 9 When the first vane 1 rotates to the second position, the angle position between the coil 21 and two adjacent first vanes 11 is corresponding, and at this time, no first vane 11 on the first vane 1 is opposite to the coil 21, and the inductance of the coil 21 is the smallest. With the clockwise or counterclockwise rotation of the first vane 1 relative to the coil 21, the first vane 1 alternately switches between the first position and the second position, so that the inductance of the coil 21 periodically fluctuates, thereby forming the frequency expression of the change of the inductance of the coil 21, and the rotation speed of the first vane 1 can be detected through the frequency of the change of the inductance, thereby identifying the flow rate of the fluid.

[0076] More specifically, as shown in Figure 9 The coil 21 has a first direction Y perpendicular to the axial arrangement of the first vane 1, and the maximum distance W4 between the magnetic cores of the circumferentially adjacent first vanes 11 is greater than the width value W3 of the coil 21 along the first direction Y. In this way, the state that the angle between the coil 21 and the adjacent first vanes 11 of the first vane 1 is corresponding and no first vane 11 is opposite to the coil 21 can be reliably formed, that is, the second position of the rotation of the first vane 1 can be more reliably formed, so that the smallest inductance of the coil 21 is smaller, and the difference between the largest inductance and the smallest inductance of the coil 21 is larger, thereby more accurately identifying the frequency of the change of the inductance of the coil 21.

[0077] Optionally, as shown in Figure 8As shown, the wire coil 21 has a second direction X parallel to the axial arrangement of the first vane 1, wherein the width value W2 of the wire coil 21 along the second direction X is greater than or equal to the axial length W1 of the first vane 1. In this way, the wire coil 21 can cover the first vane 11 to the greatest extent, so that when the first vane 11 corresponds to the wire coil 21 (for example, when the first vane 1 is in the first position), a greater maximum inductance value can be formed on the wire coil 21, so that the difference between the maximum inductance value and the minimum inductance value on the wire coil 21 is greater, so that the inductance variation frequency of the wire coil 21 can be more accurately identified.

[0078] Optionally, the width value W2 of the wire coil 21 along the second direction X is greater than the width value W3 of the wire coil 21 along the first direction Y. When the first vane 1 reaches the first position, the first vane 11 corresponds to the wire coil 21, and since the width value W2 of the wire coil 21 along the second direction X is designed to be larger, the corresponding area of the first vane 11 and the wire coil 21 is also larger, so that the maximum inductance value on the wire coil 21 is also larger in value, so as to form a more distinct inductance variation frequency, thereby improving the detection accuracy. Since the width value W3 of the wire coil 21 along the first direction Y is designed to be smaller, the first vane 11 can be arranged with a smaller spacing W4 to ensure that the wire coil 21 accurately falls into the second position, so that more first vanes 11 can be arranged on the first vane 1, so that more inductance frequency variation samples can be obtained when the first vane 1 rotates one revolution, so that the detection accuracy of the fluid flow is also higher. In combination with the foregoing, by designing the width value W2 of the wire coil 21 along the second direction X to be greater than the width value W3 of the wire coil 21 along the first direction Y, the detection accuracy of the inductance variation frequency and the sample amount of the inductance frequency variation corresponding to one revolution of the first vane 1 are taken into account, so as to improve the flow detection reliability and detection accuracy of the product.

[0079] Of course, the present application is not limited thereto, and in fact, the width of the wire coil 21 along the first direction and the width along the second direction can have various configuration relationships, and are not limited to the case where W2 is greater than W3. In other embodiments, W2 can be designed to be less than W3, or W2 can be designed to be equal to W3.

[0080] Optionally, the first vane 1 can be designed as Figure 1 and Figure 7The first fan blade 1 is provided with four first vanes 11, which are arranged in a cross shape with an equal interval along the circumference of the first central part 12, and form an angle of 90 degrees between any two adjacent first vanes 11. Of course, the present application is not limited thereto, and in other embodiments, the four first vanes 11 can be arranged in a non-uniform interval along the circumference of the first central part 12, for example, in a form of a Chinese character, so that the four first vanes 11 form two angles of more than 90 degrees and two angles of less than 90 degrees. Correspondingly, the first fan blade 1 rotates under the driving of the fluid, and the first vanes 11 and the coil disc 21 dynamically alternately approach and move away from each other, so that the inductance of the coil disc 21 changes. Specifically, when the first vanes 11 approach the coil disc 21, the corresponding inductance of the coil disc 21 is maximum, and the pulse output circuit can convert the sensed inductance into a first pulse signal and output. When the preset position (such as the middle position of the adjacent two vanes) between the adjacent two first vanes 11 approaches the coil disc 21, the corresponding inductance of the coil disc 21 is minimum, and the pulse output circuit can convert the sensed inductance into a second pulse signal and output.

[0081] Optionally, the first side of the coil disc 21 is arranged in a concave arc shape and is spaced apart from the first fan blade 1, and the second side is arranged in a convex arc shape and faces away from the first fan blade 1. As shown in Figure 7 and Figure 9 By arranging the coil disc 21 in an arc shape, the coil disc 21 has a larger surface area under the condition of the same length and width, and at the same time, when the first vanes 11 approach the coil disc 21, the radially adjacent coils of the coil disc 21 are closer to the first vanes 11, so as to more sensitively sense the magnetic core part of the first vanes 11. The response accuracy and sensitivity of the inductance of the coil disc 21 to the distance of the magnetic core part of the first vanes 11 can be further improved, so as to improve the accuracy and sensitivity of the flow detection. Of course, the present application is not limited thereto, and in other embodiments, the coil disc can also be planar.

[0082] Optionally, in combination with Figure 1 , Figure 2 , Figure 3 It can be understood that the first housing 3 has a side wall 31 arranged along the circumference to enclose a fluid channel penetrating through the two axial ends. The first fan blade 1 is rotatably arranged in the fluid channel, and is used to rotate relative to the first housing 3 under the driving of the fluid in the fluid channel. The coil disc 21 is arranged outside the side wall 31, and the surface of one side of the coil disc 21 is opposite to the outer surface of the side wall 31. The coil disc 21 is separated from the first fan blade 1 by the side wall 31. In this way, the coil disc 21 does not contact the fluid in the fluid channel, and water vapor isolation can be better achieved, and the risk of product failure can be reduced.

[0083] Optionally, the outer surface of the side wall 31 corresponding to the position of the coil 21 is provided as a convex arc surface, and the coil 21 is provided as a concave arc surface as a whole, so that the first side surface is substantially a concave arc surface, the curvature of the first side surface is substantially consistent with the curvature of the convex arc surface of the side wall 31 corresponding to the position of the coil 21, and the second side surface is substantially a convex arc surface. The first side surface of the coil 21 faces the side of the first vane 1 and abuts against the convex arc surface of the side wall 31. That is, the coil 21 is abutted against the arc surface of the side wall 31, and the arc coil 21 is arranged corresponding to the first vane 1 through the concave arc first side surface. Under the condition of the same length and width, the coil 21 has a larger surface area, and the response accuracy and sensitivity of the inductance of the coil 21 to the distance of the magnetic core part of the first vane 11 can be further improved.

[0084] Optionally, in combination with Figure 2 and Figure 3 It can be understood that the side wall 31 is provided with a groove 311 corresponding to the position of the coil 21, the coil 21 is accommodated in the groove 311, the groove 311 protrudes away from the side wall 31 around the groove 311 towards the direction away from the coil 21, and the groove 311 is located on the radial side of the first vane 1 and forms a gap with the first vane 1. By arranging the coil 21 in the groove 311, the structure of the groove 311 protruding into the fluid channel can make the coil 21 closer to the first vane 1 in the fluid channel, thereby reducing the minimum distance between the first vane 11 and the coil 21. That is, as shown in Figure 5 , when the first vane 1 reaches the first position, the distance between the first vane 11 and the coil 21 is h1, and the normal distance between the first vane 11 at the end of the first vane 1 away from the coil 21 and the outer surface of the side wall 31 of the first housing 3 is h2. By arranging the groove 311 to protrude into the fluid channel relative to the inner surface of the side wall 31, the value of h1 is smaller than h2. Compared with the case where the distance between the first vane 11 and the coil 21 is h2, the coil 21 can more sensitively sense the approach of the first vane 11 to improve the inductance, thereby improving the accuracy of flow detection. The structure of the coil 21 accommodated in the groove 311 can also be beneficial to the installation and positioning of the coil 21, and can better ensure the accuracy of the assembly and positioning of the coil 21 and the first vane 1, thereby improving the product quality consistency.

[0085] Optionally, in combination with Figure 4 , Figure 5 and Figure 6It can be understood that the bottom wall 3111 of the groove portion 311 separates the coil 21 from the first vane 1, wherein the wall thickness of the bottom wall 3111 of the groove portion 311 is smaller than the wall thickness of the side wall 31 around the groove portion 311. In this way, the minimum distance between the first vane 1 and the first blade 11 can be further reduced, so that the coil 21 can more sensitively sense the approach of the first blade 11 to increase the inductance, so as to correspondingly improve the accuracy of flow detection.

[0086] Optionally, as shown in Figure 3 , the flow guide 4 is fixed in the fluid channel, the flow guide 4 is arranged on the axial side of the first vane 1, and the flow guide 4 is used to guide the fluid, so that the fluid guided by the flow guide 4 can drive the first vane 1 to rotate. In this way, the driving efficiency of the fluid on the first vane 1 can be improved, thereby improving the detection accuracy of the fluid flow.

[0087] Optionally, in combination with Figure 1 , Figure 2 and Figure 3 It can be understood that the first housing 3 is provided with a first liquid inlet 34 and a first liquid outlet 35 which communicate with the fluid channel, the first liquid inlet 34 and the first liquid outlet 35 are arranged on the axial sides of the first vane 1, and the flow guide 4 is arranged between the first liquid inlet 34 and the first vane 1. When the liquid enters the first housing 3 from the first liquid inlet 34 and flows axially along the first housing 3, the flow guide 4 is used to guide the fluid, which can ensure that the fluid more efficiently drives the first vane 1 to rotate.

[0088] Optionally, in combination with Figure 3 and Figure 8 It can be understood that in the first vane 1, the end of each first blade 11 axially close to the flow guide 4 is respectively provided with a first inclined surface 111. In this way, for the fluid flowing axially towards the first blade 11, it can be guided by the first inclined surface 111 to the side surface of the first blade 11, thereby reducing the impact and jamming between the fluid and the first blade 11, so that the fluid flows more smoothly, which is beneficial to reduce the resistance loss of the fluid, so that the fluid more efficiently drives the first vane 1 to rotate, thereby improving the flow measurement accuracy.

[0089] Of course, the present application is not limited thereto, and in other embodiments, only a part of the first blades 11 of the first vane 1 can be provided with the first inclined surface 111, and the remaining first blades 11 are not provided with the first inclined surface 111.

[0090] Optionally, in combination with Figure 3 and Figure 8It is understood that in the first blade 1, each first blade 11 has a second inclined surface 112 at the end away from the guide member 4 along the axial direction. In this way, the fluid leaving the first blade 11 along the axial direction can be guided by the second inclined surface 112 and leave the first blade 11 more quickly, making the fluid flow smoother. This helps to reduce the fluid resistance loss and also reduces the rotational resistance of the first blade 11, thereby improving the flow measurement accuracy.

[0091] Of course, this application is not limited to this. In other embodiments, only a portion of the first blades 11 of the first fan blade 1 may be provided with the second inclined surface 112, while the remaining first blades 11 may not be provided with the second inclined surface 112.

[0092] As a further example, the flow guide 4 includes a central portion 42 and a plurality of flow guide blades 41 arranged circumferentially at intervals along the central portion 42. The flow guide blades 41 have a certain helical curvature along the axial direction, so that the fluid moving axially in the fluid channel carries a circumferential component velocity after passing through the flow guide blades 41. In this way, when the fluid carrying the circumferential component velocity flows through the first blade 11, it will drive the first fan blade 1 to rotate.

[0093] Optionally, the guide vane 41 also has a certain helical curvature in the circumferential direction, which can further improve the guiding effect on the fluid.

[0094] Optionally, such as Figure 3 As shown, the flow guide 4 also includes a ring body 44, with multiple flow guide blades 41 and a flow guide center 42 nested inside the ring body 44. One end of the flow guide blade 41 is connected to the flow guide center 42, and the other end of the flow guide blade 41 is connected to the ring body 44. This can improve the strength and stability of the flow guide blade 41, making it less prone to vibration under fluid impact, thereby reducing the flow resistance generated by the flow guide blade 41 and improving the accuracy of flow detection.

[0095] Optionally, the flow guide 4 can be configured as a one-piece injection-molded plastic component, which reduces the cost of the flow guide 4 and further lowers the product cost. Of course, in other embodiments, the flow guide 4 can also be made of materials other than plastic.

[0096] Optionally, the rotor cover 5 is connected within the fluid channel. A bracket 6 is provided at one axial end of the rotor cover 5, and a shaft hole 61 is provided on the bracket 6. The guide member 4 is connected to the end of the rotor cover 5 away from the bracket 6. The first fan blade 1 is located inside the rotor cover 5, between the guide member 4 and the bracket 6. A connecting groove 43 is provided on the center part 42 of the guide member 4. One axial end of the shaft 13 of the first fan blade 1 extends into the connecting groove 43 and can rotate within the connecting groove 43. The other axial end of the shaft 13 passes through the shaft hole 61 on the bracket 6 and can rotate within the shaft hole 61. In this way, the first fan blade 1, the guide member 4, and the bracket 6 are positioned and assembled using the rotor cover 5 as a carrier, which facilitates the positioning between the first fan blade 1 and the guide member 4 and avoids problems such as misinstallation or reverse installation of the first fan blade 1 and the guide member 4.

[0097] Alternatively, the rotor cover 5 can be configured as follows: Figure 1 The rotor cover 5, shown as a cylindrical structure extending through both ends axially, has an axially penetrating notch 51 on one radial side. The rotor cover 5 is housed within a fluid channel, with a groove 311 extending into the notch 51. This interlocking of the groove 311 and the notch restricts the rotor cover 5's rotation within the fluid channel. A stop step 32 is provided on the inner surface of the sidewall 31. The groove 311 extends axially away from the stop step 32. One end of the rotor cover 5, equipped with a support 6, abuts against the stop step 32, and a flow guide 4 axially abuts against the end of the groove 311 away from the stop step 32. The end of the rotor cover 5 with the support 6 axially abuts against the stop step 32, and the end of the rotor cover 5 with the flow guide 4 axially abuts against the groove 311, thus restricting the rotor cover 5's axial movement within the fluid channel. This achieves a fixed connection of the rotor cover 5 within the fluid channel.

[0098] With this structural design, when assembling the flow sensor, the notch 51 of the rotor cover 5 can be aligned with the groove 311, and the rotor cover 5 can be pushed into the first housing 3 from one end of the mounting bracket 6 until the end of the rotor cover 5 mounted on the mounting bracket 6 axially abuts against the stop step 32. Then, the first fan blade 1 is installed into the rotor cover 5, so that the shaft 13 of the first fan blade 1 is embedded in the shaft hole 61 of the bracket 6. Then, the flow guide 4 is connected to the end of the rotor cover 5 away from the bracket 6, and the rotor cover 5 is axially locked by the axial abutment of the flow guide 4 against the groove 311. This design has the advantage of convenient assembly.

[0099] Optionally, the connection between the flow guide 4 and the rotor cover 5 can be a snap-fit ​​type, such as having a buckle on the ring 44 of the flow guide 4 to snap into the rotor cover 5, to further improve assembly convenience. Of course, in other embodiments, the flow guide 4 and the rotor cover 5 can also be connected using screws or other connecting parts.

[0100] Optionally, the rotor cover 5 and the bracket 6 can be integrally formed, for example, the rotor cover 5 and the bracket 6 are integrally injection molded, so that the connection reliability between the bracket 6 and the rotor cover 5 is higher, so that the first fan blade 1 can be more reliably and stably supported, and the assembly steps of the rotor cover 5 and the bracket 6 are saved, and the product assembly time is saved.

[0101] Optionally, as shown in Figure 3 The outer cover 7 is located outside the side wall 31, the outer cover 7 is connected with the side wall 31 to form an accommodation space, and the coil 21 is located in the accommodation space; the circuit board 8 is located in the accommodation space, and the circuit board 8 is located on the side of the coil 21 away from the first fan blade 1, and the inductor coil 2 further includes a lead wire 22 extending from the coil 21, and the lead wire 22 is connected with the circuit board 8. In this way, the circuit board 8 and the coil 21 are packaged, which can further prevent the circuit board 8 and the coil 21 from contacting water vapor, prolong the service life of the product, and make the product applicable to high-temperature and high-humidity environments such as water heaters.

[0102] Further optionally, as shown in Figure 3 The fence part 33 is provided on the side wall 31 and protrudes relative to the outer surface of the side wall 31, the fence part 33 is distributed around the groove part 311, so that the groove part 311 and the fence part 33 jointly define an accommodation space similar to a stepped groove, the coil 21 is located in the groove part 311, the circuit board 8 is located in the area surrounded by the fence part 33 and is supported on the transition step between the groove part 311 and the fence part 33, and the outer cover 7 is covered on the side of the circuit board 8 away from the coil 21 to package the circuit board 8 and the coil 21 in the accommodation space. In this way, the circuit board 8 can further limit the coil 21, and the product is more compact in assembly, thereby saving the volume of the product.

[0103] Optionally, as shown in Figure 5 The flow sensor further includes a connection terminal 81, one end of the connection terminal 81 extends into the accommodation space and is connected with the circuit board 8, and the other end of the connection terminal 81 extends out of the accommodation space for external connection of the circuit board 8.

[0104] Optionally, as shown in Figure 10As shown, a pulse output circuit 82 is configured on the circuit board 8. The pulse output circuit 82 is connected to the inductor coil 2 (i.e., coil 21) via wires. The pulse output circuit 82 can detect changes in the inductance of the inductor coil 2 and convert these changes into different pulse signals and output them. Specifically, when the first blade 11 approaches the inductor coil 2, the pulse output circuit 82 can output a corresponding first pulse signal. When the first blade 11 approaches the inductor coil 2 at a preset position between two adjacent first blades 11, the pulse output circuit 82 can output a corresponding second pulse signal. The first pulse signal can be high-level, and the second pulse signal can be low-level. Alternatively, the first pulse signal can be low-level, and the second pulse signal can be high-level.

[0105] Optionally, such as Figure 10 As shown, the pulse output circuit 82 includes a conversion circuit 821, a signal amplification circuit 822, and a voltage comparison circuit 823. The conversion circuit 821 is electrically connected to the inductor coil 2 (i.e., the coil 21), and the conversion circuit 821 is also connected to the signal amplification circuit 822. The signal amplification circuit 822 is connected to the voltage comparison circuit 823.

[0106] The conversion circuit 821 can convert changes in the inductance of the inductor coil 2 into different pulse signals. Specifically, the conversion circuit 821 can generate an oscillating current, and the oscillation frequency output by the conversion circuit 821 can change with the change in the inductance of the inductor coil 2. Specifically, the oscillation frequency output by the conversion circuit 821 can be negatively correlated with the inductance of the inductor coil 2. That is, as the inductance of the inductor coil 2 increases, the oscillation frequency output by the conversion circuit 821 decreases, and as the inductance of the inductor coil 2 decreases, the oscillation frequency output by the conversion circuit 821 increases. At the same time, the conversion circuit 821 can also convert different pulse signals accordingly based on the detected magnitude of the inductance of the inductor coil 2.

[0107] The signal amplification circuit 822 can amplify different pulse signals output by the conversion circuit 821, facilitating subsequent signal processing. In this embodiment, the pulse signal can be a level signal. The conversion circuit 821 can convert the different inductance values ​​of the induced inductor coil 2 into different level signals, which are then amplified by the signal amplification circuit 822.

[0108] The voltage comparison circuit 823 can compare the pulse signals amplified by the signal amplification circuit 822 with a reference voltage to output first and second pulse signals that alternate. Specifically, the voltage comparison circuit 823 can compare the pulse signals amplified by the signal amplification circuit 822 (i.e., the level signals) with a reference voltage, for example, can take the pulse signals greater than or equal to the reference voltage as high-level signals, and select the maximum level signal from all the high-level signals as the first pulse signal and output; take the pulse signals less than the reference voltage as low-level signals, and select the minimum level signal from all the low-level signals as the second pulse signal and output. The voltage comparison circuit 823 can also take the pulse signals greater than or equal to the reference voltage as high-level signals, and select the maximum level signal from all the high-level signals as the second pulse signal and output; take the pulse signals less than the reference voltage as low-level signals, and select the minimum level signal from all the low-level signals as the first pulse signal and output.

[0109] The pulse output circuit 82 provided by the embodiments of the present application can output the first pulse signal when the first vane 11 is close to the inductor coil 2 (the inductance is maximum), and output the second pulse signal when the preset position between two adjacent first vanes 11 is close to the inductor coil 2 (the inductance is minimum). Thus, the first and second pulse signals that alternate can be output.

[0110] Specifically, the formula for calculating the inductance of the inductor coil is as follows:

[0111] L = μN 2 A / λ, where L represents the inductance of the inductor coil, μ represents the magnetic permeability, N represents the number of turns, A represents the winding area, and λ represents the winding length. It can be seen that the inductance L of the inductor coil is positively correlated with the magnetic permeability μ. When the first vane 1 rotates under the driving of the fluid, so that the first vane 11 (the magnetic core part) is close to the coil disc 21, the magnetic permeability μ becomes larger and the inductance L of the inductor coil becomes larger because the magnetic permeability of air is smaller than that of the first vane 11 (the magnetic core part). When the first vane 1 rotates under the driving of the fluid, so that the first vane 11 (the magnetic core part) is away from the coil disc 21, i.e., the preset position between two adjacent first vanes 11 is close to the coil disc 21, the magnetic permeability μ becomes smaller and the inductance L of the inductor coil becomes smaller because the magnetic permeability of the first vane 11 (the magnetic core part) is smaller than that of air. That is, when the first vane 1 rotates under the driving of the fluid, so that the first vane 11 (the magnetic core part) is close to the coil disc 21, the coil disc 21 generates a high inductance signal. When the first vane 1 rotates under the driving of the fluid, so that the preset position between two adjacent first vanes 11 is close to the coil disc 21, the coil disc 21 generates a low inductance signal.

[0112] Optionally, the flow sensor further comprises a frequency reduction circuit, i.e., the frequency reduction circuit can also be configured on the circuit board 8. The frequency reduction circuit is electrically connected with the pulse output circuit 82, and the frequency reduction circuit is configured to receive the pulse signal output by the pulse output circuit 82 and perform frequency reduction processing to reduce the frequency of the pulse signal. Considering that the flow sensor provided in the embodiment of the present application can multiply the number of output pulse signals in a unit of time compared with the existing flow sensor, thereby improving the measurement sensitivity, in order to be able to adapt to the existing equipment electrically connected with the existing flow sensor, the frequency reduction circuit can be arranged on the circuit board, the pulse signal output by the pulse output circuit 82 can be subjected to frequency reduction processing, so that the frequency of the pulse signal finally output by the flow sensor provided in the embodiment of the present application is the same as the frequency of the pulse signal output by the existing flow sensor.

[0113] Optionally, the flow sensor further comprises a frequency output circuit. That is, the frequency output circuit can also be configured on the circuit board 8, and the frequency output circuit is electrically connected with the pulse output circuit 82. The frequency output circuit is configured to output the frequency of the pulse signal based on the alternately changed first pulse signal and second pulse signal output by the pulse output circuit. The frequency of the pulse signal refers to the number of times of period change of the pulse signal in a unit of time. Assuming that the period of the pulse signal is T, the frequency f of the pulse signal is 1 / T, that is, the smaller the period, the greater the frequency. It can be seen that since the flow sensor provided in the embodiment of the present application can multiply the number of output pulse signals in a unit of time, that is, the period T of the pulse signal can be reduced, thereby increasing the output frequency. Compared with the existing flow sensor, the output frequency can be multiplied.

[0114] The flow sensor provided in the first embodiment has the advantages of low cost, small size and low failure rate. Moreover, the principle of changing the inductance of the inductor coil by approaching or moving away the first blade (magnetic core part) from the inductor coil is used for flow detection. Compared with the case that the first pulse signal and the second pulse signal are respectively output when the two adjacent first blades are sequentially cut by the magnetic induction line according to the principle of Hall effect, the principle of changing the inductance of the inductor coil by approaching or moving away the first blade from the inductor coil is used to output the first pulse signal when the first blade approaches the inductor coil, and output the second pulse signal when the preset position (such as the middle position of the adjacent two blades) between the two adjacent first blades approaches the inductor coil, thereby multiplying the number of output pulse signals in a unit of time, thereby improving the measurement sensitivity.

[0115] Embodiment two

[0116] The second embodiment of the present application provides a flow sensor for detecting the flow of fluid.

[0117] The difference from the above-mentioned embodiment one includes: at least a part of each first blade 11 is set as a conductive part; correspondingly, the inductive coil 2 can generate mutual inductance with at least a part of the first blade 11 in the charged state. That is, by setting the first blade 11 as a conductive part, the influence degree of mutual inductance generated by the conductive part close to or away from the inductive coil 2 on the inductance of the inductive coil 2 is different, so as to make the inductance of the inductive coil 2 different to detect the flow. Specifically, the inductive coil 2 generates a magnetic field when powered, and the first blade 11 generates eddy current in the magnetic field generated by the inductive coil 2 by cutting the magnetic induction line during the rotation close to the inductive coil 2, and the magnetic field generated by the eddy current is mutually inductive with the inductive coil 2, thereby affecting the inductance of the inductive coil 2. Similarly, the pulse output circuit 82 is connected with the inductive coil 2 through a wire. The pulse output circuit 82 can identify the change of the inductance of the inductive coil 2, and convert the change of the inductance of the inductive coil 2 into different pulse signals and output, wherein the pulse output circuit 82 can output a corresponding first pulse signal when the first blade 11 is close to the inductive coil 2, and output a corresponding second pulse signal when the inductive coil 2 is close to the preset position between the adjacent two first blades 11. Wherein, the first pulse signal can be high level, and the second pulse signal can be low level. The first pulse signal can also be low level, and the second pulse signal can also be high level.

[0118] Optionally, the first blade 11 includes a blade body part and a conductive part, the blade body part is an insulator, and the conductive part is embedded in the blade body part. Exemplarily, the conductive part can be a metal sheet. The metal sheet is embedded in the blade body part, so that the eddy current generated by cutting the magnetic induction line of the metal sheet can be controlled not to flow out of the blade, and the duration of the eddy current can be prevented from being too short to effectively interact with the charged inductive coil 2. Moreover, the blade body part is set as an insulator, so that the magnetic field can be prevented from attracting impurities.

[0119] Optionally, the conductive part is a conductive non-magnetic material, so that the metal impurities can be prevented from being attracted.

[0120] Although the present application has been described with reference to several exemplary embodiments, it is understood that the terms used are illustrative and not restrictive terms. Since the present application can be embodied in various forms without departing from the spirit or essential characteristics thereof, it should be understood that the above-described embodiments are not limited to any of the aforementioned details, but are to be construed broadly within the spirit and scope of the appended claims, and all changes and modifications that fall within the metes and bounds of the claims, or equivalents of such metes and bounds, are therefore intended to be embraced by the appended claims.

Claims

1. A flow sensor, characterized by The flow sensor comprises: a first fan having two or more first blades arranged circumferentially at intervals; an inductive coil, wherein the first fan is configured to rotate under the driving of fluid, so that the first blades and the inductive coil dynamically alternately approach and move away from each other, so that the inductance of the inductive coil changes; a pulse output circuit electrically connected to the inductive coil, the pulse output circuit being configured to output alternating first and second pulse signals, wherein the first pulse signal is a signal corresponding to the output when the first blades approach the inductive coil, and the second pulse signal is a signal corresponding to the output when a preset position between two adjacent first blades approaches the inductive coil.

2. The flow sensor of claim 1, wherein, The pulse output circuit comprises a conversion circuit, a signal amplification circuit and a voltage comparison circuit; wherein the conversion circuit is electrically connected to the inductive coil, the signal amplification circuit is electrically connected to the conversion circuit, and the voltage comparison circuit is electrically connected to the signal amplification circuit; The conversion circuit is configured to convert the change in inductance of the inductive coil into different pulse signals; The signal amplification circuit is configured to amplify different pulse signals; The voltage comparison circuit is configured to compare the amplified pulse signals with a reference voltage to output alternating first and second pulse signals.

3. The flow sensor of claim 1, wherein, At least a portion of each first blade is arranged as a magnetic core portion, which is a soft magnetic material. Correspondingly, the inductive coil comprises a wire coil, the end faces of the wire coil at the two axial ends are respectively a first side and a second side, the first side is configured as a spiral coil, the wire coil is arranged on one side of the first fan in the radial direction, the first side is spaced apart from the first fan, and the first fan is configured to rotate relative to the wire coil under the driving of fluid, so that the first blades and the wire coil dynamically alternately approach and move away from each other.

4. The flow sensor of claim 3, wherein, Each first blade is arranged as a whole as the magnetic core portion; or a portion of each first blade is arranged as a magnetic core portion, wherein the first blade comprises a blade body portion and the magnetic core portion, and the magnetic core portion is fixed to the blade body portion.

5. The flow sensor of claim 1, wherein, At least a portion of each first blade is arranged as a conductive portion; correspondingly, the inductive coil can generate mutual inductance with at least a portion of the first blade in a charged state.

6. The flow sensor of claim 5, wherein, The first blade comprises a blade body portion and the conductive portion, the blade body portion is an insulator, and the conductive portion is embedded in the blade body portion.

7. The flow sensor of claim 5 or 6, wherein, The conductive portion is a conductive non-magnetic material.

8. The flow sensor of claim 1, wherein, The flow sensor further comprises a frequency reduction circuit electrically connected to the pulse output circuit, the frequency reduction circuit being configured to receive the pulse signal output by the pulse output circuit and perform frequency reduction processing to reduce the frequency of the pulse signal.

9. The flow sensor of claim 1, wherein, The flow sensor further comprises a frequency output circuit electrically connected to the pulse output circuit, the frequency output circuit being configured to output the frequency of the pulse signal based on the alternating first and second pulse signals output by the pulse output circuit.

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