CN220602608U - Flow sensor and water supply equipment - Google Patents

Abstract

The utility model belongs to the technical field of flow detection, and particularly discloses a flow sensor and water supply equipment. The flow sensor comprises a water receiving pipe with a restriction port structure, a main shell with a mounting cavity, a diaphragm unit and an electromagnetic induction assembly. The diaphragm unit is used for sealing and separating the mounting cavity into a first cavity and a second cavity, the first cavity is communicated with the restriction orifice structure or the downstream of the restriction orifice structure, and the second cavity is communicated with the upstream of the restriction orifice structure; the electromagnetic induction assembly comprises an excitation piece, an induction coil and a circuit board, wherein the excitation piece is arranged on the diaphragm unit, the induction coil is arranged on the main shell, and the fluid pressure difference of the first cavity and the second cavity can push the diaphragm unit to act along a first direction so as to change the interval between the excitation piece and the induction coil; the elastic member is used for applying an elastic force against the fluid pressure difference to the diaphragm unit. The water supply device comprises the flow sensor. The flow sensor disclosed by the utility model can improve the detection accuracy and the service life of the flow sensor.

Description

Flow sensor and water supply equipment

Technical Field

The utility model relates to the technical field of flow detection, in particular to a flow sensor and water supply equipment.

Background

In the use process of the water heater, the cold water inflow or the hot water outflow needs to be detected in real time so as to better regulate and control the operation of the water heater.

The existing flow sensor applied to the water heater is usually a vortex flowmeter, a rotor with a magnet is arranged in the middle of a waterway of the vortex flowmeter, and blades are arranged on the rotor; the detection shell on the side face of the rotor is provided with a Hall element. When water flows through the rotor, the rotor rotates, the Hall element cuts the rotating magnetic field of the rotor magnet, generates periodically changing frequency, and transmits the periodically changing frequency to the main board of the water heater. The faster the water flow speed through the water path, the higher the rotational speed at which the rotor rotates, and thus the higher the output frequency. And the main board reads the flow data according to the calibrated frequency, so that the corresponding heat load is matched.

The prior art adopts vortex flowmeter to detect flow, has following problems:

1. the rotor rotates when water flows through, so that the rotor rotates for a long time, further blades are worn to influence accuracy, the accuracy of detection is difficult to maintain for a long time, and periodic verification is needed;

2. because the rotor and the blades are arranged in the waterway, the requirements on the cleanliness of water flow are high, if the water flow encounters strip-shaped foreign matters such as hair, adhesive tapes and the like, the strip-shaped foreign matters are easy to wind on the rotor, and the normal and reliable use of the rotor is influenced;

3. The change of the flow velocity of the water flow can cause the change of the rotating speed of the rotor, so that the output frequency of the vortex flowmeter is greatly influenced by the fluctuation of the water flow, and the vortex flowmeter is not suitable for the occasion of rapid change of the flow or the flow velocity.

Disclosure of Invention

One of the technical problems to be solved by the utility model is to provide a flow sensor, which can effectively solve the problems that the long-term use precision of the existing flow sensor cannot be guaranteed, the requirement on the cleanliness of water flow is high, and the flow speed and the flow rate are not applicable to the rapid change scene due to the fact that the existing flow sensor is easy to wear during long-term movement, improve the long-term use precision of the flow sensor, reduce the requirement on water quality, and improve the universality of the flow sensor and the applicability of different use scenes.

The second technical problem to be solved by the utility model is to provide the water using equipment, which can effectively solve the problem of inaccurate flow detection caused by long-term use, low water flow cleanliness or severe water flow change of the existing water using equipment, improve the reliability and accuracy of flow detection, and improve the use reliability of the water using equipment.

The first technical problem is solved by the following technical scheme:

a flow sensor, comprising:

The water receiving pipe comprises a through water receiving channel, wherein the water receiving channel is partially narrowed to form a flow limiting port structure and is used for generating a pressure difference of fluid flowing through the water receiving channel;

the main shell is arranged at one side of the water receiving pipe and is provided with an installation cavity;

the diaphragm unit is arranged in the mounting cavity and is used for sealing and separating the mounting cavity into a first cavity and a second cavity which are arranged side by side in a first direction, the first cavity is communicated with the downstream of the restriction port structure, and the second cavity is communicated with the upstream of the restriction port structure;

the electromagnetic induction assembly comprises an excitation piece, an induction coil and a circuit board, wherein the excitation piece is arranged on the diaphragm unit and is positioned in the first cavity, the induction coil is arranged on the outer side wall of the main shell, which is away from the second cavity, the circuit board is arranged on the main shell and is electrically connected with the induction coil, and the diaphragm unit can be pushed by the fluid pressure difference of the first cavity and the second cavity to act along a first direction so as to change the interval between the excitation piece and the induction coil;

and the elastic piece is positioned in the first cavity and is used for applying elastic force against the fluid pressure difference to the diaphragm unit.

Compared with the background technology, the flow sensor has the following beneficial effects:

through arranging the restriction port structure at the water receiving pipe, when fluid flows through the restriction port structure, pressure difference is formed at two sides of the restriction port structure, the pressure difference can push the diaphragm unit to act, and then the distance between the exciting piece and the induction coil is changed, so that the inductance value of the induction coil is changed, and the inductance value can be converted into a calibrated flow value through detection of the inductance value, so that the detection of flow is realized; when the pressure at two sides of the diaphragm unit is balanced, the diaphragm unit stops moving, so that the diaphragm unit only changes when the flow rate of water flows, keeps standing when no water flows or the water flows pass through the diaphragm unit with constant flow, effectively reduces the movement frequency of the diaphragm unit, reduces abrasion, and the induction coil is not contacted with the fluid, thus the service life of the flow sensor can be prolonged, and the flow sensor can keep better precision in long-term use;

because the detection main body formed by the main shell, the diaphragm unit, the electromagnetic induction component and the elastic piece is arranged on the outer side of the water receiving pipe, only the water receiving pipe is connected into the detection waterway, and the structures in the detection main body are all arranged outside the detection waterway, so that the condition that impurities or foreign matters in the waterway influence the detection main body can be effectively improved, and the use reliability and the detection precision of the flow sensor are ensured;

The flow detection of the detection waterway can be realized only by connecting the two ends of the water receiving pipe into the detection waterway, so that the convenience in mounting, dismounting and maintaining the flow sensor can be effectively improved;

moreover, as the pressure of the water receiving pipe is led to the two sides of the diaphragm unit, the pressure difference of the two sides of the diaphragm unit is insensitive to transient flow, thereby avoiding the action of the diaphragm unit caused by transient flow change, leading the output signal not to be easy to severely fluctuate, and having high signal output stability, namely higher detection reliability and detection precision.

In one embodiment, the main housing comprises a first housing and a second housing which are connected in a buckled manner, the first housing and the second housing surround to form the installation cavity, and the periphery of the diaphragm unit is clamped between the first housing and the second housing; the water receiving pipes extend along a second direction, the second shell is located between the first shells and connected with the water receiving pipes, and the second direction is perpendicular to the first direction.

In one embodiment, the diaphragm unit includes a diaphragm, the diaphragm is made of an elastic material, the diaphragm includes a moving portion, a deformation portion and an installation portion, the moving portion, the deformation portion and the installation portion are sequentially connected from the center to the periphery, the installation portion is clamped between the first shell and the second shell in a sealing manner, the moving portion can move along the first direction relative to the installation portion through deformation of the deformation portion, and the exciting element is installed on the moving portion.

In one embodiment, the outer wall of the water receiving pipe is connected with a drainage pipe part, an inner cavity of the drainage pipe part forms a first drainage channel, a first end of the first drainage channel is in sealing connection with the downstream of the restriction port structure, the drainage pipe part penetrates through the second shell and the periphery of the diaphragm unit, the second end of the drainage pipe part is inserted into the first shell, and the second end of the first drainage channel is in sealing communication with the first cavity.

In one embodiment, the second housing is provided with a second drainage channel, the second drainage channel extends along the first direction, two ends of the second drainage channel are respectively communicated with the second cavity and the upstream of the restriction port structure, the diaphragm unit is provided with a guide part extending along the first direction, and the guide part is inserted into the second drainage channel.

In one embodiment, the flow sensor further comprises a cover body, wherein the cover body is detachably arranged on one side, away from the second shell, of the first shell, and an electric cavity is formed by surrounding the cover body and the first shell; the induction coil and the circuit board are both installed in the electric cavity.

In one embodiment, the first shell is provided with a mounting cylinder part protruding outwards along a first direction, an inner cavity of the mounting cylinder part forms a containing cavity, a first end of the containing cavity is communicated with the mounting cavity, and a second end of the containing cavity is closed;

The exciting piece part stretches into the accommodating cavity, and the induction coil is sleeved on the outer side of the mounting cylinder part.

In one embodiment, the outer side surface of the first shell is convexly provided with a separation ring part, the separation ring part is coaxial with the mounting cylinder part and is sleeved at intervals, and the induction coil is mounted between the separation ring part and the mounting cylinder part;

and/or the mounting cylinder part penetrates out of the cover body.

In one embodiment, the mounting cylinder is internally threaded with an adjusting plug, the adjusting plug seals the second end of the accommodating cavity, and two ends of the elastic piece are respectively abutted to the adjusting plug and the diaphragm unit.

The second technical problem is solved by the following technical scheme:

a water supply apparatus comprising a flow sensor as described above.

Compared with the background technology, the water supply equipment has the following beneficial effects: by adopting the flow sensor, the water supply equipment provided by the utility model can improve the flow detection reliability, simplify the structure and improve the use reliability of the water supply equipment.

Drawings

FIG. 1 is a schematic diagram of a flow sensor according to a first embodiment of the present utility model;

Fig. 2 is a schematic diagram of a split structure of a flow sensor according to a first embodiment of the present utility model;

FIG. 3 is a cross-sectional view of a flow sensor according to a first embodiment of the present utility model;

FIG. 4 is an enlarged view of a portion of the portion I of FIG. 3;

FIG. 5 is a schematic diagram of a waterway of a flow sensor according to an embodiment of the present utility model in a detection state;

FIG. 6 is a schematic structural diagram of a diaphragm unit according to a first embodiment of the present utility model;

fig. 7 is a schematic structural diagram of a first housing according to a first embodiment of the present utility model;

FIG. 8 is a partial cross-sectional view of a water receiving pipe according to a second embodiment of the present utility model;

fig. 9 is a partial cross-sectional view of a water receiving tube according to a third embodiment of the present utility model.

Description of the reference numerals:

1. a main housing; 11. a first housing; 111. a first main housing portion; 1111. a first cavity; 1112. drainage grooves; 1113. drainage holes; 112. a mounting cylinder part; 1121. a receiving chamber; 113. a mounting ring portion; 1131. a clamping groove; 114. a spacer ring portion; 12. a second housing; 121. a second cavity; 122. a second drainage channel; 13. a drainage tube part; 131. a first drainage channel; 14. a threaded fastener;

2. a diaphragm unit; 21. a diaphragm; 211. a mounting part; 212. a deformation section; 213. a moving part; 214. a guide part; 215. a clamping convex part; 216. a boss; 217. a lug part; 22. a mounting base; 221. a main board section; 2211. a step hole; 222. a connecting tube part; 2221. a notch; 2222. a mounting groove; 223. a hook part; 224. an edge portion; 225. positioning convex parts;

3. An electromagnetic induction assembly; 31. an exciting member; 32. an induction coil; 33. a circuit board; 34. a signal transmission line;

4. a water receiving pipe; 41. a water receiving channel; 411. a restriction orifice structure; 4111. a first mouth; 4112. a second mouth; 4113. a transition flow chamber; 4114. a restriction orifice; 412. a high pressure flow chamber; 413. a low pressure flow chamber; 42. an orifice plate portion; 5. an elastic member; 6. adjusting a plug; 61. mounting a head; 62. sealing the head; 63. a post section; 64. a mounting groove; 7. a seal ring;

8. a cover body; 81. a cover body; 82. a coaming part; 83. a convex clamping part; 84. an electrical cavity.

Detailed Description

The following description of the embodiments of the present application will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all, of the embodiments of the present application. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are within the scope of the present disclosure.

In the description of the present application, it should be understood that the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like indicate orientations or positional relationships based on the orientation or positional relationships shown in the drawings, merely to facilitate description of the present application and simplify the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present application.

The terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present application, unless otherwise indicated, the meaning of "a plurality" is two or more.

In the description of the present application, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the terms in this application will be understood by those of ordinary skill in the art in a specific context.

The embodiment provides a flow sensor, and it utilizes the pressure difference that produces when fluid flows through the throttle structure to realize flow measurement based on the throttle principle of fluid flow, and flow sensor's measurement accuracy is high, simple to operate.

As shown in fig. 1 to 3, in particular, the flow sensor includes a water receiving pipe 4 and a detection body. The water receiving pipe 4 is used for being in butt joint with a waterway to be detected, the water receiving pipe 4 is provided with a through water receiving channel 41, the water receiving channel 41 is locally contracted to form a restriction port structure 411, the water passing area of the restriction port structure 411 is smaller than the cross-sectional area of the rest positions of the water receiving channel 41, and therefore when water flow in the waterway flows through the restriction port structure 411, pressure difference can be generated between the upstream and the downstream of the restriction port structure 411. The detecting body is located at one side of the water receiving pipe 4, and is used for detecting the pressure difference between the upstream and downstream of the restriction structure 411, thereby detecting the water flow passing through the water receiving pipe 4.

The detection main body comprises a main shell 1, a diaphragm unit 2, an electromagnetic induction assembly 3 and an elastic piece 5. The main housing 1 has a mounting cavity in which the diaphragm unit 2 is movably mounted in the first direction and hermetically separates the mounting cavity into a second cavity 121 and a first cavity 1111 arranged side by side in the first direction, the first cavity 1111 being in communication with the restriction structure 411 or downstream of the restriction structure 411, the second cavity 121 being in communication with upstream of the restriction structure 411; the electromagnetic induction assembly 3 comprises an exciting element 31, an induction coil 32 and a circuit board 33, wherein the exciting element 31 is arranged on the diaphragm unit 2 and is positioned in the first cavity 1111, the induction coil 32 is arranged on the outer side wall of the main shell 1, which is far away from the second cavity 121, the circuit board 33 is arranged on the main shell 1 and is electrically connected with the induction coil 32, and the fluid pressure difference between the first cavity 1111 and the second cavity 121 can push the diaphragm unit 2 to act along the first direction so as to change the interval between the exciting element 31 and the induction coil 32; the elastic member 5 is used to apply an elastic force against the fluid pressure difference to the diaphragm unit 2.

When water flows through the water receiving pipe 4, as the water receiving pipe 4 is internally provided with the restriction port structure 411, according to the Bernoulli principle, the speed is increased and the pressure is reduced when the water flows through the restriction port structure 411, so that a relatively high-pressure flow area is formed at the upstream of the restriction port structure 411, a relatively low-pressure flow area is formed at the downstream of the restriction port structure 411 and a pressure difference is generated at the upstream and downstream of the restriction port structure 411. Because the second cavity 121 is in sealing communication with the upstream of the restriction 411, the first cavity 1111 is in sealing communication with the restriction 411 or the downstream of the restriction 411 such that the pressure in the second cavity 121 is the same as the pressure at which the high pressure flow region is in communication with the second cavity 121, the pressure in the first cavity 1111 is the same as the pressure at which the low pressure flow chamber is in communication with the first cavity 1111, and there is a fluid pressure differential between the second cavity 121 and the first cavity 1111; the fluid pressure difference acts on the diaphragm unit 2 to push the diaphragm unit 2 to act along a first direction, so that the exciting element 31 is pushed to move along a direction towards the induction coil 32, the distance between the exciting element 31 and the induction coil 32 is changed, the magnetic field of the induction coil 32 is changed, and the inductance value of the induction coil 32 is changed; the change in inductance value of the induction coil 32 is transmitted to the circuit board 33, so that the frequency of the output signal changes after the circuit board 33 processes.

That is, the frequency value output by the circuit board 33 corresponds to the interval between the induction coil 32 and the exciting member 31, and the interval corresponds to the fluid pressure difference between the second cavity 121 and the first cavity 1111, which corresponds to the flow rate of the fluid flowing through the water pipe 4, and the detected flow rate value can be obtained by calibrating the relationship between the frequency and the flow rate at the time of design through the frequency value output by the circuit board 33.

According to the flow sensor provided by the embodiment, the flow limiting structure 411 is arranged at the water receiving pipe 4, so that the pressure difference at two sides of the flow limiting structure 411 can push the diaphragm unit 2 to act, the distance between the exciting piece 31 and the induction coil 32 is changed, flow detection is realized, and when the pressure at two sides of the diaphragm unit 2 is balanced, the diaphragm unit 2 stops moving, so that the diaphragm unit 2 keeps still when no water flow or constant flow of water passes, the diaphragm unit 2 does not need to keep a moving state when the flow passes, the moving frequency of the diaphragm unit 2 is effective, abrasion is reduced, the service life of the flow sensor is prolonged, and the flow sensor can keep good precision in long-term use; because the detection main body is arranged at the outer side of the water receiving pipe 4, only the water receiving pipe 4 is connected into the detection waterway, and the structures in the detection main body are all outside the detection waterway, so that the influence of impurities or foreign matters in the detection waterway on the detection main body can be effectively avoided, the detection failure caused by the foreign matters is avoided, and the use reliability and the detection precision of the flow sensor are ensured; the flow detection of the detection waterway can be realized only by connecting the two ends of the water receiving pipe 4 into the detection waterway, so that the convenience in mounting, dismounting and maintaining the flow sensor can be effectively improved; moreover, as the pressure of the water receiving pipe 4 is led to the two sides of the diaphragm unit 2, the pressure difference of the two sides of the diaphragm unit 2 is insensitive to instantaneous flow, so that the action of the diaphragm unit 2 caused by the instantaneous flow change is avoided, the output signal is not easy to severely fluctuate, and the signal output stability is high, namely the detection reliability and the detection precision are higher; furthermore, since the exciting element 31 is mounted on the diaphragm unit 2 and the induction coil 32 is mounted on the main housing 1, the problem that the connecting wires between the induction coil 32 and the circuit board 33 are pulled due to the fact that the diaphragm unit 2 drives the induction coil 32 to act can be avoided, and the use reliability of the electromagnetic induction assembly 3 is improved.

In an embodiment, the water receiving tube 4 preferably extends along a second direction, and the second direction is perpendicular to the first direction, so as to improve convenience in draining the fluid in the water receiving tube 4 into the first cavity 1111 and the second cavity 121, and facilitate the arrangement of the parts of the detecting body. In other embodiments, the water receiving pipe 4 may extend in the first direction or may extend in a direction inclined with respect to the first direction.

For convenience of description, the portion of the water receiving channel 41 located upstream of the restriction 411 will be referred to as a high pressure flow chamber 412, and the portion located downstream of the restriction 411 will be referred to as a low pressure flow chamber 413, but it will be understood that the low pressure flow chamber 413 and the high pressure flow chamber 412 refer only to the relative relationship of fluid pressures, and that the internal fluid pressure needs to be higher than a certain flow value or lower than a certain flow value; meanwhile, since the flow rate of the fluid is maximum and the fluid pressure is minimum when the fluid passes through the restriction structure 411, and the fluid pressure is gradually recovered when flowing downstream of the restriction structure 411, that is, the fluid pressure of the low pressure flow chamber 413 is not equal everywhere, but gradually increases in a direction away from the restriction structure 411, and is recovered to the same fluid pressure as the high pressure flow chamber 412 at the distal end of the low pressure flow chamber 413 or at the detection waterway.

The side wall of the water receiving channel 41 is provided with a high-pressure drainage port and a low-pressure drainage port, the high-pressure drainage port is communicated with the high-pressure flow cavity 412 and the second cavity 121, and the low-pressure drainage port is communicated with the restriction port structure 411 or the low-pressure flow cavity 413. The spacing between the high pressure vent and the restriction structure 411 is preferably greater than the first spacing so that the fluid pressure at the high pressure vent is as high as possible at the inlet end of the water conduit 4, the spacing between the low pressure vent and the restriction structure 411 is preferably less than the second spacing, and the fluid pressure at the high pressure vent is greater than the fluid pressure at the low pressure vent.

The first and second intervals should be specifically determined according to the ratio of the minimum flow area of the restriction structure 411 to the cross-sectional area of the water receiving channel 41, the feedback speed and the detection accuracy required by the flow sensor, and the like, so long as the fluid pressure of the high-pressure drainage port is ensured to be higher than the fluid pressure at the low-pressure drainage port.

It should be noted that, when the dimensions of the water receiving channel 41 and the restriction structure 411 are determined, the further the low pressure drainage port is from the restriction structure 411, the smaller the fluid differential pressure between the low pressure drainage port and the high pressure drainage port is, i.e. the smaller the fluid differential pressure between the first cavity 1111 and the second cavity 121 is at the beginning of the detection; when the spacing between the high pressure vent and the low pressure vent and the restriction structure 411 is determined, the greater the ratio of the minimum flow area of the restriction structure 411 to the cross-sectional area of the water receiving channel 41, the greater the fluid differential pressure between the high pressure vent and the low pressure vent at the same flow rate.

The sensitivity of the flow sensor is related to the fluid pressure difference and the elastic force of the elastic member 5 at the beginning, when the elastic force of the elastic member 5 at the beginning is unchanged, the smaller the minimum fluid pressure difference required for pushing the diaphragm unit 2 to move, i.e. the smaller the flow change generating the fluid pressure difference, the higher the sensitivity of the flow sensor.

If the inner diameter of the water receiving channel 41 is D, and the inner diameter of the restriction 411 is D, the relationship between the pressure difference and the aperture ratio can be obtained according to bernoulli equation:

wherein Δp is the pressure differential; q is water flow; beta is the ratio of D to D; ρ is the density of the fluid.

In one embodiment, the restriction 411 is a cylindrical hole, and the cross-sectional areas of the high pressure flow chamber 412 and the low pressure flow chamber 413 are equal everywhere to simplify the processing of the water receiving tube 4. Further, the inner wall of the water receiving pipe 4 is vertically connected with an orifice portion 42, and the orifice portion 42 is provided with the restriction structure 411.

The distance from the high-pressure drainage port and the low-pressure drainage port to the pore plate part 42 can be selected according to actual detection requirements, so long as detection can be completed; in one embodiment, the water receiving channel 41 has an inner diameter D, a distance l1=d from the low pressure vent to the orifice plate 42, and a distance l2=d/2 from the high pressure vent to the orifice plate 42.

In order to improve the convenience of the water receiving pipe 4 in accessing the detection waterway, in an embodiment, the two ends of the water receiving pipe 4 are provided with external threads, so that the water receiving pipe 4 can be conveniently connected with the pipeline of the detection waterway in a threaded manner, the connection convenience and reliability of the water receiving pipe 4 are improved, and the tightness after connection is easier to ensure.

In order to facilitate the disassembly and assembly of the structures such as the diaphragm unit 2 and the electromagnetic induction assembly 3, in an embodiment, the main housing 1 comprises a first housing 11 and a second housing 12 which are buckled and connected along a first direction, a mounting cavity is formed around the first housing 11 and the second housing 12, and the periphery of the diaphragm unit 2 is clamped between the first housing 11 and the second housing 12 in a sealing manner. This arrangement facilitates the disassembly and assembly of the diaphragm unit 2, the elastic member 5, and the electromagnetic induction assembly 3 by the disassembly and assembly of the second casing 12 and the first casing 11.

In an embodiment, the second housing 12 is located between the first housing 11 and the water receiving pipe 4, and the second housing 12 is connected to the water receiving pipe 4, the second housing 12 and the first housing 11 enclose a mounting cavity, and the second cavity 121 is located between the first cavity 1111 and the water receiving channel 41. Namely, the water receiving pipe 4, the second shell 12 and the first shell 11 are arranged side by side in the first direction, so that the connection between the main shell 1 and the water receiving pipe 4 is simplified, only the second shell 12 is connected with the water receiving pipe 4, and the reliability and the sealing performance after the connection are ensured; at the same time, the structural size of the flow sensor in the first direction is also reduced.

The second housing 12 is provided with a first drainage channel 131 communicating the high pressure drainage port with the first cavity 1111 and a second drainage channel 122 communicating the low pressure drainage port. In an embodiment, the second housing 12 is welded or integrally formed with the water receiving tube 4 to ensure the connection stability of the water receiving tube 4 and the second housing 12, so as to facilitate the sealing arrangement of the first drainage channel 131 and the second drainage channel 122, reduce the probability of fluid leakage, and avoid the need of providing a sealing structure between the second housing 12 and the water receiving tube 4. In other embodiments, the second housing 12 and the water receiving tube 4 may be detachably connected by screws. The second drainage channel 122 and the first drainage channel 131 preferably both extend in the first direction, whereby the ease of opening of the first drainage channel 131 and the second drainage channel 122 can be improved.

The second housing 12 is preferably connected to the first housing 11 using threaded fasteners 14 to ensure the connection stability of the second housing 12 and the first housing 11, the threaded fasteners 14 preferably being provided in a plurality of spaced apart relation around the mounting cavity. In one embodiment, the first housing 11 and the second housing 12 are integrally formed in a square structure, and fastening screws are provided at four corners of each of the first housing 11 and the second housing 12. In other embodiments, the first housing 11 and the second housing 12 may also have a disc-type structure, and a plurality of fastening screws are provided at intervals along the circumferential direction of the first housing 11.

In an embodiment, when the first cavity 1111 and the second cavity 121 have a fluid pressure difference, the fluid pressure difference pushes the diaphragm unit 2 to move in the first direction toward the exciting member 31 and the sensing coil 32, so that the larger the fluid pressure difference is, the smaller the distance between the exciting member 31 and the sensing coil 32 is, the larger the frequency output by the circuit board 33 is, so that the frequency size corresponds to the flow size better, and the convenience and reliability of signal identification are improved.

The main housing 1 includes a drain tube portion 13, a first end of the drain tube portion 13 is vertically connected with an outer wall of the water receiving tube 4, the drain tube portion 13 passes through the second housing 12 and a second end protrudes out of an end face of the second housing 12, and the second end of the drain tube portion 13 is inserted into the first housing 11. The inner cavity of the drain tube portion 13 forms a first drain channel 131. Because the first cavity 1111 is located at a side of the diaphragm unit 2 away from the water receiving pipe 4, the above arrangement facilitates the implementation of the arrangement of the first drainage channel 131, and at the same time, the end face of the second housing 12 and the end face of the first housing 11 may be arranged in a fitting manner, so as to ensure the connection convenience and the tightness after the connection of the second housing 12 and the first housing 11. The drain tube portion 13 is preferably integrally formed with the first housing 11.

Further, a drainage groove 1112 is formed on the end face of the first housing 11, a drainage hole 1113 communicating with the first cavity 1111 is formed on a groove wall of one side of the drainage groove 1112, the drainage groove 1112 and the drainage hole 1113 are combined to form the switching flow passage, and the second end of the drainage tube portion 13 is inserted into the drainage groove 1112. That is, the low pressure drain port communicates with the first cavity 1111 through the first drain passage 131, the drain groove 1112, and the drain hole 1113.

In an embodiment, the diaphragm unit 2 comprises a diaphragm 21, the diaphragm 21 being made of an elastic material, the periphery of the diaphragm 21 being fixedly connected to the main housing 1, the central area of the diaphragm 21 being connected to the aforementioned excitation member 31, the diaphragm 21 having the ability to deform in the first direction. That is, when a fluid pressure difference exists on both sides of the diaphragm 21, the diaphragm 21 is pushed to deform in the first direction by the fluid pressure difference, so that the diaphragm unit 2 acts in the first direction. By the arrangement, the diaphragm 21 does not need to move along the first direction entirely, so that the boundaries of the second cavity 121 and the first cavity 1111 on the periphery are fixed, sealing between the first cavity 1111 and the second cavity 121 is realized more favorably, the leakage probability between the second cavity 121 and the first cavity 1111 is reduced, and the structural arrangement is simplified; meanwhile, as no moving contact exists between the diaphragm unit 2 and the main shell 1, abrasion to the diaphragm unit 2 is avoided, reliability and use precision of the diaphragm unit 2 in a long-term use process can be guaranteed more favorably, and detection precision of the flow sensor in the long-term use process can be guaranteed better.

In other embodiments, the diaphragm unit 2 may also be slidably connected to the wall of the mounting cavity, such that the diaphragm unit 2 moves entirely in the first direction within the main housing 1, wherein a moving seal is provided between the diaphragm unit 2 and the wall of the mounting cavity.

As shown in fig. 3, 4 and 6, the diaphragm 21 further includes a moving portion 213, a deforming portion 212 and an attaching portion 211 sequentially provided from the center to the periphery, the attaching portion 211 is sealed and fixedly connected to the main casing 1, the moving portion 213 is movable in the first direction relative to the attaching portion 211 by deformation of the deforming portion 212, and the exciting element 31 is attached to the moving portion 213. This arrangement allows the diaphragm 21 to deform only on the deformation portion 212, and the moving portion 213 can move entirely in the first direction, so that the directional accuracy of the movement of the exciting element 31 in the first direction, that is, the detection accuracy of the flow sensor, can be better ensured.

The thickness of the moving part 213 and the thickness of the mounting part 211 are both larger than the thickness of the deforming part 212, so that the deforming part 212 has smaller thickness and stronger flexibility, thereby being beneficial to concentrating the deformation of the diaphragm 21 to convenience, and the thicknesses of the moving part 213 and the mounting part 211 are relatively larger, being beneficial to increasing the overall structural strength and rigidity of the moving part 213, and ensuring that the moving part 213 can move integrally along the first direction; at the same time, the thickness of the mounting portion 211 is larger, which is more beneficial to ensuring the connection reliability of the mounting portion 211 and the main housing 1.

The thickness of the deformation portion 212, the moving portion 213 and the mounting portion 211 is gradually increased, and preferably, the thickness at the deformation portion 212 is 0.1mm to 1mm.

In an embodiment, the cross section of the deformation portion 212 is preferably an arc-shaped structure with an opening toward the second cavity 121, so as to ensure that the deformation portion 212 has a larger deformation capability, i.e. better ensures the movement stroke of the moving portion 213 along the first direction.

The mounting portion 211 is preferably interposed between the second housing 12 and the first housing 11, which is advantageous in improving the connection convenience of the mounting portion 211 and the main housing 1. Meanwhile, since the diaphragm 21 is made of an elastic material, the mounting portion 211 has elasticity, and the mounting portion 211 is clamped between the second housing 12 and the first housing 11, so that the tightness between the second housing 12 and the first housing 11 can be directly realized, and the joint of the second housing 12 and the first housing 11 is prevented from being additionally provided with other sealing structures. Preferably, the opposite surfaces of the second housing 12 and the first housing 11 are respectively provided with a mounting ring groove, two opposite sides of the mounting portion 211 are respectively inserted into the mounting ring grooves, and the mounting portion 211 is abutted with the groove walls of the mounting ring grooves.

The drain portion 13 preferably passes through the septum 21. Specifically, the mounting portion 211 is provided with a lug portion 217 protruding outward, the lug portion 217 is disposed opposite to the drain tube portion 13, a through hole is provided in the lug portion 217, and the drain tube portion 13 passes through the lug portion 217 through the through hole.

To better ensure the reliability of the movement of the moving portion 213 along the first direction, in an embodiment, a guide portion 214 is convexly disposed on a side of the moving portion 213 away from the exciting element 31, the guide portion 214 extends along the first direction, a guide hole is formed in the mounting cavity opposite to the cavity wall of the guide portion 214, and the guide portion 214 is inserted into the guide hole. By sliding the guide portion 214 in the guide hole, the movement of the moving portion 213 in the first direction is guided. The guide hole is preferably the second drainage channel 122, thereby enabling a simplified structure and reduced cost.

Further, the diaphragm 21 has a circular structure, and the moving portion 213, the deforming portion 212 and the mounting portion 211 are concentrically arranged, so that the overall stress balance of the diaphragm 21 can be improved, thereby ensuring the movement reliability of the moving portion 213 along the first direction and further ensuring the detection accuracy of the flow sensor. Further, the guide 214 is located in the center of the circular structure, thereby helping to ensure that the diaphragm unit 2 is centrally located and helping to provide positioning for the installation of the diaphragm unit 2. The first cavity 1111 and the second cavity 121 are both circular cavities.

In an embodiment, the side of the moving portion 213 facing away from the exciting element 31 is convexly provided with a plurality of protruding portions 216, and the protruding portions 216 are beneficial to avoiding the sticking together of the moving portion 213 and the cavity wall of the second cavity 121 without generating a vacuum adsorption effect, so as to ensure the normal use of the diaphragm unit 2.

In an embodiment, the diaphragm unit 2 further includes a mounting seat 22, the mounting seat 22 is connected to a side of the moving portion 213 away from the water receiving pipe 4, the exciting member 31 is mounted on the mounting seat 22, and the material hardness of the mounting seat 22 is greater than that of the diaphragm 21, so that the structure of the moving portion 213 of the diaphragm unit 2 can be thickened, and the moving portion 213 is ensured to move integrally only along the first direction without deformation in other directions; at the same time, the arrangement of the mounting seat 22 is also beneficial to increasing the supporting performance of the central area of the diaphragm unit 2, and ensures that the exciting element 31 can be stably and reliably mounted on the diaphragm unit 2.

In one embodiment, the diaphragm 21 is made of a silicone material and the mount 22 is made of a rigid plastic.

In order to improve the convenience of assembling and disassembling the diaphragm 21 and the mounting seat 22, the mounting seat 22 is in clamping connection with the diaphragm 21, so that the problems of sealing difficulty and processing difficulty increase caused by the fact that holes or grooves are formed in the diaphragm 21 are avoided. In an embodiment, a plurality of clamping protrusions 215 are convexly arranged on one side of the moving portion 213, which faces away from the water receiving pipe 4, bayonets are arranged on the mounting base 22, the clamping protrusions 215 are arranged in a one-to-one correspondence with the bayonets, and the clamping protrusions 215 are clamped in the bayonets. Thereby ensuring the structural integrity of the diaphragm 21 and thus the tightness between the second cavity 121 and the first cavity 1111. The engaging protrusion 215 is provided in plurality around the guide 214 at intervals.

The clamping protrusion 215 includes a clamping head portion and a connecting portion, the clamping head portion has a truncated cone structure, a large end of the clamping head portion faces the moving portion 213, and the connecting portion is connected between the clamping head portion and the moving portion 213. The large diameter of the clamping head part is larger than the aperture of the bayonet, the connecting part is arranged in the bayonet in a penetrating way, and the large end face of the clamping head part is abutted with the mounting seat 22. In an embodiment, the mounting seat 22 is provided with the step holes 2211, the step holes 2211 are arranged in one-to-one correspondence with the clamping head parts, the small hole parts of the step holes 2211 are positioned on one side of the large hole parts facing the moving part 213, the small hole parts of the step holes 2211 form bayonets, and the end surfaces of the clamping head parts are abutted on the step surfaces between the small hole parts and the large hole parts, so that the clamping head parts partially extend into the small hole parts, and the height dimension of the protruding moving parts 213 of the clamping convex parts 215 is reduced on the basis that the whole thickness of the mounting seat 22 is unchanged.

The mounting base 22 includes a main plate 221 and a connecting tube 222 protruding from the main plate 221, the main plate 221 and the connecting tube 222 are coaxially disposed, the main plate 221 is attached to the moving portion 213, and the main plate 221 is provided with the stepped hole 2211. The exciting piece 31 is of an annular structure, and the exciting piece 31 is sleeved on the connecting cylinder part 222, so that the connecting cylinder part 222 provides positioning for the installation of the exciting piece 31, and the installation convenience of the exciting piece 31 is improved; meanwhile, the arrangement is beneficial to realizing that the exciting element 31 is arranged at the center of the diaphragm unit 2, and ensures the stress stability and the movement reliability of the diaphragm unit 2. The exciting member 31 may be made of a metal material or may be made of a magnet.

In an embodiment, in order to prevent the exciting element 31 from being separated from the connecting cylinder portion 222, a hook portion 223 is extended from one end of the connecting cylinder portion 222 away from the main board 221, and two ends of the exciting element 31 are respectively abutted with the hook portion 223 and the connecting ring portion, that is, the hook portion 223 is hooked to the exciting element 31, so that the mounting position of the exciting element 31 and the mounting seat 22 in the first direction can be limited, and the mounting stability of the exciting element 31 on the mounting seat 22 is ensured. The cross section of the hook 223 is a right triangle, and a right-angle side of the right triangle abuts against the end surface of the exciting element 31 to provide guidance for the hook 223 to pass through the center hole of the exciting element 31.

Further, the connection tube portion 222 is provided with a mounting groove 2222 with an opening deviating from the main board portion 221, a notch 2221 is formed in a penetrating manner in the groove side wall of the mounting groove 2222, the notch 2221 extends to the end face of the connection tube portion 222, a plurality of notches 2221 are arranged at intervals along the circumferential direction of the connection tube portion 222, and elastic hooks are formed at the portions between two adjacent notches 2221, so that the excitation piece 31 can be sleeved on the connection tube portion 222, and meanwhile the excitation piece 31 can be fastened on the mounting seat 22 through the elastic hooks, and the assembly efficiency of the excitation piece 31 on the diaphragm unit 2 is improved.

The peripheral edge of the main plate 221 is provided with a protruding edge 224 along a direction away from the diaphragm 21, and the edge 224 is beneficial to enhancing the overall structural strength of the mounting seat 22 and reducing the probability of deformation and damage of the mounting seat 22.

In an embodiment, the flow sensor further includes a cover 8, the cover 8 is detachably disposed on the outer side of the main housing 1, and an electrical cavity 84 is formed around the cover 8 and the main housing 1, and the induction coil 32 and the circuit board 33 are both mounted in the electrical cavity 84. This arrangement is advantageous in that the circuit board 33 and the induction coil 32 are prevented from being exposed to the environment with water, and the electrical safety of the electromagnetic induction assembly 3, i.e., the electrical safety of the flow sensor, is further improved.

As shown in fig. 3, 4 and 7, in one embodiment, the main housing 1 has a mounting cylinder 112 protruding in a first direction, an inner cavity of the mounting cylinder 112 forms a receiving cavity 1121, a first end of the receiving cavity 1121 communicates with the mounting cavity, and a second end of the receiving cavity 1121 is closed; the exciting element 31 partially extends into the accommodating cavity 1121, and the induction coil 32 is sleeved outside the mounting cylinder 112. By the arrangement, the size of the mounting cavity in the first direction can be reduced while the mounting space of the exciting element 31 and the elastic element 5 is ensured, so that the size of the whole detection main body is reduced, and the compactness of the structure is improved; meanwhile, the arrangement can reduce the radial dimensions of the induction coil 32 and the exciting element 31, so that the exciting element 31 can extend into the inner side of the induction coil 32 when the exciting element 31 moves along the direction close to the induction coil 32, thereby increasing the induction quantity of the induction coil 32 and increasing the sensitivity; furthermore, the induction coil 32 is sleeved on the mounting tube 112, which is also beneficial to realizing the mounting and positioning of the induction coil 32 and improving the mounting convenience of the induction coil 32.

Specifically, the first housing 11 includes a first main housing portion 111 and an installation tube portion 112, a first cavity 1111 is opened on a side of the first main housing portion 111 facing the second housing 12, and the first main housing portion 111 is fastened to the second housing 12. The mounting cylinder 112 is disposed at a side of the first main housing portion 111 remote from the first cavity 1111.

In an embodiment, the installation tube portion 112 is internally and threadedly connected with the adjusting plug 6, the adjusting plug 6 plugs the second end of the accommodating cavity 1121, and two ends of the elastic member 5 are respectively abutted against the adjusting plug 6 and the diaphragm unit 2. Namely, in the present embodiment, the second end of the accommodating cavity 1121 is sealed by adjusting the plug 6, so that the processing of the first housing 11 can be simplified; meanwhile, as the adjusting plug 6 is in threaded connection with the mounting tube 112, the distance between the adjusting plug 6 and the diaphragm unit 2 in the initial state can be adjusted by adjusting the screwing depth of the screw thread of the plug 6 relative to the mounting tube 112, so that the compression degree of the elastic piece 5 in the initial state can be adjusted, namely, the output frequency can be adjusted by adjusting the pretightening force applied by the elastic piece 5 on the diaphragm unit 2 in the initial state.

To facilitate the installation of the elastic member 5, the first end of the elastic member 5 extends into the installation groove 2222 of the connection cylinder portion 222 and abuts against the groove bottom of the installation groove 2222. Preferably, the bottom of the mounting groove 2222 is convexly provided with a positioning convex part 225, and the first end of the elastic piece 5 is sleeved on the positioning convex part 225. The positioning protrusion 225 is preferably a truncated cone with a small end facing the adjustment plug 6.

The adjusting plug 6 has a mounting groove 64 towards one end of the exciting element 31, a convex column portion 63 is convexly arranged at the bottom of the mounting groove 64, the second end of the elastic element 5 is sleeved on the convex column portion 63, and the second end of the elastic element 5 is abutted with the bottom of the mounting groove 64. This makes it unnecessary for the elastic member 5 to be connected to the adjustment plug 6, and at the same time, it is possible to ensure that the elastic member 5 deforms in the extending direction of the boss portion 63.

The adjusting plug 6 includes a mounting head portion 61 and a sealing head portion 62 connected in the axial direction, and the mounting head portion 61 is provided with an external thread, a mounting groove 64, and a boss portion 63. The sealing head 62 is located the one side that the installation head 61 kept away from the excitation piece 31, and the sealing groove has been seted up to the installation head 61 lateral wall, is provided with sealing washer 7 in the sealing groove, and sealing washer 7 extrudees between the inner wall of holding chamber 1121 and the tank bottom of sealing groove, can realize adjusting the leakproofness between end cap 6 and the first casing 11 better from this.

In an embodiment, the mounting cylinder 112 penetrates the cover 8, so that the adjusting plug 6 is exposed outside the main casing 1, and the adjusting plug 6 can be screwed without disassembling the main casing 1, so that the position of the adjusting plug 6 is adjusted. Further, a knife groove is formed in the exposed end face of the adjusting plug 6, and the knife groove can be in a cross shape or a straight line shape and the like, so that the wrench is conveniently adopted to screw the adjusting plug 6, and screwing convenience of the adjusting plug 6 is improved.

To improve the convenience of the installation of the induction coil 32 in the electric chamber 84, the outer side surface of the main casing 1 is provided with a spacer ring portion 114, the spacer ring portion 114 is coaxial with the installation tube portion 112 and is sleeved at a distance, and the induction coil 32 is installed between the spacer ring portion 114 and the installation tube portion 112. The isolation ring 114 is beneficial to providing positioning and limiting for the installation of the induction coil 32, and avoiding the radial shaking of the induction coil 32; meanwhile, the isolation ring 114 is beneficial to isolating the induction coil 32 from the electric devices on the circuit board 33, so as to improve the induction reliability of the induction coil 32 to the exciting element 31. Preferably, the side wall of the isolating ring 114 is provided with an opening, and the connecting wire of the induction coil 32 and the circuit board 33 passes through the opening.

The electromagnetic induction assembly 3 further comprises a signal transmission line 34, a first end of the signal transmission line 34 is electrically connected with the circuit board 33, and a second end of the signal transmission line 34 penetrates out of the cover body 8.

In order to improve the connection convenience between the first housing 11 and the cover 8, an end of the first main housing portion 111 facing away from the housing is provided with a mounting ring portion 113. The cover body 8 comprises a cover body 8 part and a coaming part 82 arranged on the periphery of the cover body 8 part, the coaming part 82 is matched with the mounting part 211 in shape, the mounting ring part 113 is inserted into the inner side of the cover body 8, and the mounting ring part 113 is connected with the cover body 8. The provision of the mounting ring portion 113 is advantageous in providing a location for the mounting of the cover 8 on the first housing 11.

One of the mounting ring portion 113 and the coaming portion 82 is provided with a clamping groove 1131, the other one is provided with a clamping convex portion 83, the clamping convex portions 83 are in one-to-one correspondence with the clamping grooves 1131, and the clamping convex portions 83 are clamped in the clamping grooves 1131, so that clamping connection between the mounting ring portion 113 and the cover body 8 is realized, namely clamping connection between the first shell 11 and the cover body 8 is realized.

In one embodiment, the cover 8 has a rectangular structure, the mounting ring portion 113 has a rectangular annular structure, and at least two opposite sides of the mounting ring portion 113 are clamped with the corresponding coaming portions 82. An avoidance port for outputting a signal transmission line is formed in the mounting ring portion 113 and the corresponding coaming portion 82.

The embodiment also provides water supply equipment, which comprises the flow sensor. The water supply equipment provided by the embodiment can improve the flow detection reliability of the water supply equipment by adopting the flow sensor, simplify the structure of the water supply equipment and improve the use reliability of the water supply equipment. The water supply device can be a water heater, a tap, a water purifier and the like.

Example two

As shown in fig. 8, the present embodiment provides a flow sensor and a water supply device, and the flow sensor and the water supply device provided in the present embodiment are substantially the same as those in the foregoing embodiments, and only the arrangement of the water receiving pipe 4 is different, so that the present embodiment will not be repeated for the same structure as the foregoing embodiments.

In the present embodiment, the restriction structure 411 includes a first port portion 4111 and a second port portion 4112 communicating in the flow direction, the cross-sectional area of the first port portion 4111 gradually decreases in the direction toward the second port portion 4112, and the cross-sectional area of the second port portion 4112 is the same as the minimum cross-sectional area of the first port portion 4111. By the arrangement, the flow limiting port structure 411 forms a nozzle structure, so that the flow velocity flowing through the flow limiting port structure 411 can be further increased, the fluid pressure difference between the upstream and the downstream of the flow limiting port structure 411 is increased, and the detection sensitivity of the flow sensor is improved.

Further, the inner wall of the water receiving pipe 4 is convexly provided with a hole plate portion 42, the hole plate portion 42 is convexly provided with a boss portion along the flow direction, and the restriction orifice structure 411 penetrates through the boss portion and the hole plate portion 42 to reduce the thickness of the hole plate portion 42 while ensuring the opening size of the restriction orifice structure 411.

Example III

As shown in fig. 9, the present embodiment provides a flow sensor and a water supply device, and the flow sensor and the water supply device provided in the present embodiment are substantially the same as those in the foregoing embodiments, and only the arrangement of the water receiving pipe 4 is different, and the present embodiment will not be repeated for the same structure as the foregoing embodiments.

In this embodiment, the restriction structure 411 adopts a venturi structure, which is beneficial to realizing uniform transition of flow velocity and pressure of water flow and reducing turbulence degree, thereby reducing noise generated by flow.

In the present embodiment, the venturi is formed with two transition flow chambers 4113, and a restriction 4114 between the two transition flow chambers 4113, the cross-sectional area of the transition flow chamber 4113 gradually decreases in a direction toward the restriction 4114, and the maximum cross-sectional area of the transition flow chamber 4113 is the same as the cross-sectional areas of the corresponding high-pressure flow chamber 412 and low-pressure flow chamber 413, respectively.

In this embodiment, the low pressure drain is provided on the side wall of the restriction 4114.

In the specific content of the above embodiment, any combination of the technical features may be performed without contradiction, and for brevity of description, all possible combinations of the technical features are not described, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The foregoing detailed description of the embodiments presents only a few embodiments of the present utility model, which are described in some detail and are not intended to limit the scope of the present utility model. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the utility model, which are all within the scope of the utility model. Accordingly, the scope of protection of the present utility model is to be determined by the appended claims.

Claims (10)

1. A flow sensor, comprising:

a water receiving pipe (4) comprising a through water receiving channel (41), wherein the water receiving channel (41) is locally narrowed to form a restricted port structure (411) for generating a pressure difference of fluid flowing through the water receiving channel (41);

a main housing (1) arranged at one side of the water receiving pipe (4) and provided with an installation cavity;

a diaphragm unit (2) arranged in the mounting cavity and used for sealing and separating the mounting cavity into a first cavity (1111) and a second cavity (121) which are arranged side by side in a first direction, wherein the first cavity (1111) is communicated with the downstream of the restriction structure (411), and the second cavity (121) is communicated with the upstream of the restriction structure (411);

the electromagnetic induction assembly (3) comprises an excitation piece (31), an induction coil (32) and a circuit board (33), wherein the excitation piece (31) is installed on the diaphragm unit (2) and is located in the first cavity (1111), the induction coil (32) is installed on the outer side wall of the main shell (1) deviating from the second cavity (121), the circuit board (33) is installed on the main shell (1) and is electrically connected with the induction coil (32), and the fluid pressure difference between the first cavity (1111) and the second cavity (121) can push the diaphragm unit (2) to act along a first direction so as to change the interval between the excitation piece (31) and the induction coil (32);

-an elastic member (5), said elastic member (5) being located in said first cavity (1111) for applying an elastic force against said fluid pressure difference to said membrane unit (2).

2. The flow sensor according to claim 1, characterized in that the main housing (1) comprises a first housing (11) and a second housing (12) which are connected in a snap-fit manner, the first housing (11) and the second housing (12) enclosing to form the mounting cavity, the periphery of the diaphragm unit (2) being sandwiched between the first housing (11) and the second housing (12); the water receiving pipes (4) extend along a second direction, the second shell (12) is located between the first shells (11) and connected with the water receiving pipes (4), and the second direction is perpendicular to the first direction.

3. The flow sensor according to claim 2, wherein the diaphragm unit (2) includes a diaphragm (21), the diaphragm (21) is made of an elastic material, the diaphragm (21) includes a moving portion (213), a deforming portion (212) and a mounting portion (211) which are sequentially connected from the center to the outer periphery, the mounting portion (211) is sealingly sandwiched between the first housing (11) and the second housing (12), the moving portion (213) is movable in the first direction relative to the mounting portion (211) by deformation of the deforming portion (212), and the exciting member (31) is mounted to the moving portion (213).

4. The flow sensor according to claim 2, characterized in that the outer wall of the water receiving tube (4) is connected with a drainage tube portion (13), an inner cavity of the drainage tube portion (13) forms a first drainage channel (131), a first end of the first drainage channel (131) is in sealing communication with a downstream of the restriction opening structure (411), the drainage tube portion (13) passes through the second housing (12) and a periphery of the diaphragm unit (2) and the second end is inserted into the first housing (11), and a second end of the first drainage channel (131) is in sealing communication with the first cavity (1111).

5. The flow sensor according to claim 2, characterized in that the second housing (12) is provided with a second drainage channel (122), the second drainage channel (122) extends along the first direction, two ends of the second drainage channel are respectively communicated with the second cavity (121) and the upstream of the restriction structure (411), the diaphragm unit (2) is provided with a guide part (214) extending along the first direction, and the guide part (214) is inserted into the second drainage channel (122).

6. The flow sensor according to any one of claims 2-5, further comprising a cover (8), wherein the cover (8) is detachably arranged on a side of the first housing (11) facing away from the second housing (12), and wherein an electrical cavity (84) is formed by the cover (8) surrounding the first housing (11); the induction coil (32) and the circuit board (33) are both mounted to the electrical cavity (84).

7. The flow sensor according to claim 6, wherein the first housing (11) has a mounting cylinder portion (112) protruding in a first direction, an inner cavity of the mounting cylinder portion (112) forming a receiving cavity (1121), a first end of the receiving cavity (1121) being in communication with the mounting cavity, a second end of the receiving cavity (1121) being closed;

the exciting element (31) partially extends into the accommodating cavity (1121), and the induction coil (32) is sleeved outside the mounting cylinder (112).

8. The flow sensor according to claim 7, wherein an outer side surface of the first housing (11) is convexly provided with a spacer ring portion (114), the spacer ring portion (114) is coaxial with the mounting tube portion (112) and is sleeved at a distance, and the induction coil (32) is mounted between the spacer ring portion (114) and the mounting tube portion (112);

and/or the mounting cylinder (112) penetrates out of the cover (8).

9. The flow sensor according to claim 7, characterized in that the mounting cylinder (112) is internally threaded with an adjusting plug (6), the adjusting plug (6) plugs the second end of the accommodating cavity (1121), and two ends of the elastic piece (5) are respectively abutted with the adjusting plug (6) and the diaphragm unit (2).

10. A water supply apparatus comprising a flow sensor as claimed in any one of claims 1 to 9.