CN112254243B

CN112254243B - Micropore humidifying device

Info

Publication number: CN112254243B
Application number: CN202010961473.3A
Authority: CN
Inventors: 朱怀照; 刘标奇; 杨坤; 刘轶; 张燕燕
Original assignee: Dongguan Weijie Industrial Co ltd
Current assignee: Shenzhen Lexin Technology Service Co ltd
Priority date: 2020-09-14
Filing date: 2020-09-14
Publication date: 2021-08-27
Anticipated expiration: 2040-09-14
Also published as: CN112254243A

Abstract

The application relates to a micropore humidifying device, which relates to the technical field of atomization and humidification, and comprises a water bottle and a humidifier arranged on the water bottle, wherein a water replenishing pipe communicated with the humidifier is arranged in the water bottle, the humidifier comprises a shell, a water tank, an atomization component and a water delivery part, the shell is connected with the water bottle, the water tank, the atomization component and the water delivery part are all positioned in the shell, the water tank is provided with a water replenishing end and a water guide end, the water delivery part is communicated with the water replenishing pipe and the water replenishing end of the water tank, the atomization component is provided with a water inlet end and a mist outlet end, the water inlet end is communicated with the water guide end, the height position of the water guide end is higher than that of the water inlet end, so that water in the water tank can flow into the atomization component from the water guide end to the water inlet end under the action of self gravity, the atomization component atomizes the part of water and discharges the atomized water from the mist outlet end, therefore, the micropore humidifying device solves the problem of insufficient atomization amount caused by self-priming of traditional capillary in a self-weight water guide way, thereby improving the atomization amount of the micropore humidifying device.

Description

Micropore humidifying device

Technical Field

The application relates to the technical field of atomization humidification, in particular to a micropore humidification device.

Background

A humidifier is an electrical device that increases the humidity of the surrounding environment by delivering water in an atomized form.

The mainstream humidifiers in the market are all piezoelectric ceramic plates which vibrate at the bottom of a water tank at high frequency to generate water mist, and the water mist is blown out through a fan. Such humidifiers consume significant energy (typically 20-40 watts) and are costly, and require a dedicated power adapter.

In order to reduce the cost, another mode of atomizing water by the micropore humidifying device is to adopt a micropore atomizing sheet, namely a mode of vibrating piezoelectric ceramics. The humidifier drives the piezoelectric ceramics to vibrate, and dense small holes (generally 4-6 um) formed in the piezoelectric ceramics can throw water out, so that dense water mist is formed. The microporous atomization sheet has the advantages of low cost and low power consumption (generally 3-5 watts), and can be powered by a battery.

With respect to the related art among the above, the inventors consider that the following drawbacks exist: the microporous atomizing sheet needs to be closely attached to water, so a cotton swab is generally used in the industry, and the cotton swab is conveyed to the microporous atomizing sheet through the capillary self-absorption principle of the cotton swab. However, the atomization amount of water in the mode is small (generally 30ml/h-50 ml/h), and the requirement of the universal humidifier atomization amount in the industry (generally 250ml/h-350 ml/h) is far from being met.

Disclosure of Invention

In order to solve the problem that the atomization amount of the micropore humidifying device is insufficient, the application aims to provide the micropore humidifying device.

The application provides a micropore humidification device adopts following technical scheme:

the utility model provides a micropore humidification device, include the water-jug with set up in the humidifier of water-jug, be provided with the intercommunication in the water-jug the moisturizing pipe of humidifier, the humidifier includes shell, water tank, atomizing component and send water spare, the shell with the water-jug is connected, the water tank atomizing component with send water spare all to be located in the shell, the water tank has moisturizing end and water guide end, send water spare intercommunication moisturizing pipe with the moisturizing end of water tank, atomizing component has into water end and play fog end, intake the end with water guide end intercommunication, the high position of water guide end is higher than the high position of end of intaking.

Through adopting above-mentioned technical scheme, send the water supply in the water part extraction water-jug and enter into the water tank, and because the high position of water guide end is higher than the high position of the end of intaking, so that water in the water tank can be through water guide end under the effect of self gravity to the end flow entering atomization component that intakes, this part water of atomization component atomizing and with the atomizing water from the end discharge of fog, therefore, make this micropore humidification device solve the problem that traditional capillary is from inhaling the atomizing volume that leads to not enough through the mode of dead weight water guide, thereby improve this micropore humidification device's atomizing volume.

Preferably, the water guide end is connected with a damping pipe, and the end part of the damping pipe is communicated with the water inlet end.

Through adopting above-mentioned technical scheme, the damping pipe is through the liquid resistance in the control tube in order to reduce water pressure to the realization is to the rivers flow control of water tank internal flow to atomizing component, and control is stable.

Preferably, the atomizing subassembly including install in the fog seat of shell with install in the fog lid of fog seat, the end of intaking is located on the fog seat, install the intercommunication in the fog seat the nozzle of end of intaking, be provided with on the nozzle with the micropore atomizing piece that the fog seat is connected, the opening terminal surface slope of nozzle sets up, micropore atomizing piece with the opening of nozzle corresponds the slope.

Through adopting above-mentioned technical scheme, the water in the water tank is carried for micropore atomizing piece via the nozzle, and micropore atomizing piece still can the air of breathing in when shaking atomizing water, and micropore atomizing piece slope is so that the micropore opening face slope of micropore atomizing piece this moment to destroy micropore open-ended pressure so that optimize the carminative effect of micropore, from this, make this micropore humidification device can effectively solve the exhaust problem.

Preferably, the micropore atomization sheet inclines towards the direction far away from the water inlet end, and the inclination angle alpha of the micropore atomization sheet is 15-30 degrees.

By adopting the technical scheme, when the inclination angle alpha of the micropore atomization sheet is 15-30 degrees, the air in the micropores is discharged more efficiently under the vibration effect, so that the exhaust effect of the micropore humidification device is better.

Preferably, the installation platform has in the fog seat, install the briquetting on the fog seat, the briquetting with be formed with the intake antrum between the installation platform bottom, the nozzle is located the intake intracavity, micropore atomizing piece is located the briquetting is close to the one side of nozzle.

Through adopting above-mentioned technical scheme, the opening of nozzle is less so that area of contact between nozzle and the micropore atomizing piece is less, and the inlet chamber is filled earlier with water transport to the nozzle, and the water of back inlet chamber is large tracts of land and micropore atomizing piece contact to increase the water yield that can atomize in the micropore atomizing piece unit time, from this, improve this micropore humidification device's atomizing volume.

Preferably, the pressing block is provided with a high end and a low end, the pressing block is provided with a mist outlet matched with the micropore atomization sheet, the high end of one side, far away from the water inlet cavity, of the pressing block is provided with a water retaining edge and a water outlet hole, the water retaining edge is wound on the mist outlet hole, the water outlet hole is located on one side, far away from the mist outlet hole, of the water retaining edge, and the water outlet hole is communicated with the water inlet cavity.

Through adopting above-mentioned technical scheme, the setting of apopore can be higher than the peak of micropore atomizing piece so that the intracavity retaining water level of intaking to guarantee the water acquisition volume of micropore atomizing piece, and manger plate is along blockking the rivers income fog outlet that spills over from the apopore, avoids this partial water to hinder micropore atomizing piece and produces water smoke.

Preferably, the bottom of the fog seat is provided with a recovery hole, and the recovery hole is communicated with the water bottle.

Through adopting above-mentioned technical scheme, the water that overflows from the apopore and the water that the fog lid condensed the backward flow flows back to the water-jug so that this partial hydroenergy can reuse through retrieving the hole, and avoids this partial hydroenergy to pile up in the fog seat and the water that leads to deteriorate smellily.

Preferably, the mounting table is provided with a small hole communicated with the water inlet cavity, and the small hole is positioned at the lower end of the water inlet cavity.

Through adopting above-mentioned technical scheme, when this micropore humidification device was out of work for a long time, the water of storage in the intracavity of intaking can flow out slowly through the aperture, avoids the intracavity of intaking to store water for a long time and produces the water rotten, smelly scheduling problem.

Preferably, the fog base is provided with an air supply part for blowing air into the fog base.

Through adopting above-mentioned technical scheme, the air supply part is bloied so that the atomizing water in the fog seat can flow to the play fog end smoothly to improve this micropore humidification device's play fog volume so that the humidification function stably realizes in the fog seat.

Preferably, have high liquid level position and low liquid level position in the water tank, be provided with the control in the shell send the control part that water spare opened and close, the control part includes:

the high liquid level sensor is arranged at the high liquid level position of the water tank and senses whether water at the high liquid level position in the water tank exists or not so as to output a high liquid level detection signal;

the low liquid level sensor is arranged at the low liquid level position of the water tank and is used for sensing whether water at the low liquid level position in the water tank exists or not so as to output a low liquid level detection signal;

and the controller is arranged in the shell and responds to the high liquid level detection signal and the low liquid level detection signal to control the opening and closing of the water feeding piece.

By adopting the technical scheme, when the water level in the water tank is lower than the low liquid level position, the controller controls the water feeding piece to be started so as to convey water into the water tank, and when the water level in the water tank is higher than the low liquid level position but lower than the high and low liquid level positions, the water feeding piece keeps a starting state so as to continue to convey water into the water tank until the water level in the water tank is higher than the high liquid level position, and the controller controls the water feeding piece to be closed; the water in the water tank gradually decreases towards the atomization assembly, when the water level in the water tank is higher than the low liquid level position but lower than the high and low liquid level positions, the water feeding piece is kept in a closed state, and the controller controls the water feeding piece to be started until the water level in the water tank is lower than the low liquid level position; therefore, the water supply part can automatically supply water to keep the water quantity in the water tank stable, and the water supply part does not need to be started all the time to reduce the energy consumption of the micropore humidifying device.

In summary, the present application includes at least one of the following beneficial technical effects:

1. the water in the water bottle is pumped by the water feeding part and enters the water tank, and the height position of the water guide end is higher than that of the water inlet end, so that the water in the water tank can flow to the water inlet end through the water guide end under the action of self gravity and enter the atomization assembly, and the atomization assembly atomizes the part of water and discharges the atomized water from the mist outlet end, so that the problem of insufficient atomization amount caused by traditional capillary self-absorption is solved by the microporous humidifying device through a self-gravity water guide mode, and the atomization amount of the microporous humidifying device is increased;

2. the damping pipe reduces the water pressure by controlling the liquid resistance in the pipe, thereby realizing the flow control of the water flow flowing to the atomization assembly in the water tank and having stable control;

3. the water in the water tank is conveyed to the micropore atomization sheet through the nozzle, the micropore atomization sheet can suck air when vibrating atomized water, and the micropore atomization sheet inclines to incline the micropore opening surface of the micropore atomization sheet, so that the pressure of the micropore opening is damaged to optimize the micropore exhaust effect, and therefore, the micropore humidification device can effectively solve the exhaust problem;

4. the arrangement of the water outlet hole ensures that the water level of the stored water in the water inlet cavity can be higher than the highest point of the micropore atomization sheet, so that the water acquisition amount of the micropore atomization sheet is ensured, the water retaining edge can block water overflowing from the water outlet hole from flowing into the mist outlet, and the water in the water retaining edge is prevented from blocking the micropore atomization sheet to generate water mist;

5. when this micropore humidification device was out of work for a long time, the water of storage in the intracavity of intaking can flow out slowly through the aperture, avoids the intracavity of intaking to store water for a long time and produces the water rotten, smelly scheduling problem.

Drawings

FIG. 1 is a schematic diagram of the overall structure of an embodiment of the present application;

FIG. 2 is a schematic diagram of an exploded view of a humidifier according to an embodiment of the present application;

FIG. 3 is a schematic diagram of an exploded view of an atomizing assembly in accordance with an embodiment of the present disclosure;

FIG. 4 is a schematic top view of an atomizing assembly in accordance with an embodiment of the present disclosure;

fig. 5 is a schematic sectional view of a portion a-a in fig. 4.

In the figure, 1, a water bottle; 2. a humidifier; 21. a housing; 211. a base; 22. a water tank; 23. an atomizing assembly; 231. a fog cover; 232. a mist seat; 2321. a water inlet end; 2322. an installation table; 233. a nozzle; 234. a microporous atomizing sheet; 235. briquetting; 2351. a mist outlet; 2352. a water retaining edge; 236. a water inlet cavity; 2361. a water outlet hole; 2362. a small hole; 237. a recovery hole; 24. a water delivery member; 25. a damper tube; 26. an air supply member; 27. a controller; 3. a water replenishing pipe; .

Detailed Description

The present application is described in further detail below with reference to figures 1-5.

The embodiment of the application discloses micropore humidification device.

Referring to fig. 1, a microporous humidifying device includes a water bottle 1 and a humidifier 2 disposed on the water bottle 1, and the water bottle 13 is a water bottle 1 commonly used in the market and is not described herein again. In this embodiment, the water bottle 1 and the humidifier 2 are detachably connected by a screw or a snap. A water replenishing pipe 3 communicated with the humidifier 2 is arranged in the water bottle 1, and the humidifier 2 extracts water in the water bottle 1 through the water replenishing pipe 3 to atomize.

Referring to fig. 2, the humidifier 2 includes a housing 21, a water tank 22, an atomizing assembly 23, and a water delivery member 24. One end of the housing 21 close to the water bottle 1 is provided with a base 211, and the base 211 is detachably connected with the water bottle 1. The water tank 22, the atomization assembly 23 and the water feeding piece 24 are all located in the shell 21, and the water tank 22, the atomization assembly 23 and the water feeding piece 24 are all installed on the base 211. In this embodiment, the water supply member 24 may be a water pump, and the water supply pipe 3 passes through the base 211 to enter the housing 21, and then is connected to the water supply member 24. The power supply of the water feeding member 24 may be an upper battery provided on the base 211, or may be an external power supply through a power adapter.

Referring to fig. 2 and 3, the water tank 22 has a replenishing end and a water guiding end, and the replenishing end communicates with the water feeding member 24 so that the water feeding member 24 can replenish the water in the water bottle 1 into the water tank 22. Correspondingly, the atomizing assembly 23 has a water inlet end 2321 and a mist outlet end, and the height position of the water guide end is higher than that of the water inlet end 2321. The water guide end is connected with a damping pipe 25, and the end part of the damping pipe 25 is communicated with the water inlet end 2321. In the present embodiment, the damping tube 25 is a slender common water guiding tube, and the diameter and length of the damping tube 25 need to be matched with the actual water delivery amount. The damping tube 25 reduces the water pressure by controlling the fluid resistance in the tube, and the water in the water tank 22 can flow into the atomizing assembly 23 through the water guiding end to the water inlet end 2321 under the action of the self gravity.

Specifically, referring to fig. 3, the atomizing assembly 23 includes a mist seat 232 mounted to the housing 21 and a mist cover 231 mounted to the mist seat 232, wherein the water inlet 2321 is located on the mist seat 232, and the mist outlet is located on the mist cover 231. A recovery hole 237 is formed at the bottom of the mist seat 232, and the recovery hole 237 penetrates through the base 211 downwards to communicate with the water bottle 1, so that the redundant water in the mist seat 232 can flow back into the water bottle 1 through the recovery hole 237.

Referring to fig. 4 and 5, the mist seat 232 has a mounting table 2322 therein, the mounting table 2322 has a pressing block 235 mounted at a position near the center of the mist seat 232, and the pressing block 235 is inclined downward in a direction near the center of the mist seat 232 such that the pressing block 235 has a high end and a low end. An inlet cavity 236 is formed between the pressing block 235 and the bottom of the mounting table 2322. The water inlet end 2321 is located in the water inlet chamber 236 and the water inlet end 2321 is located below the high end of the pressure block 235. The inlet chamber 236 is provided with a nozzle 233 communicated with the inlet 2321. The opening of the nozzle 233 faces upward, and the opening end surface of the nozzle 233 is lower than the water guide end of the water tank 22. The opening end face of the nozzle 233 is inclined, and the fine pore atomizing sheet 234 is inclined corresponding to the opening of the nozzle 233. The nozzle 233 fed from the damping tube 25 can be ejected through the nozzle 233 to fill the inlet chamber 236.

The side of the pressing block 235 close to the nozzle 233 is provided with a microporous atomization sheet 234, and the microporous atomization sheet 234 is positioned on the side of the pressing block 235 close to the nozzle 233. The micro-porous atomization sheet 234 vibrates to draw water from the water intake chamber 236 for atomization. The micro-porous atomization sheet 234 is attached to the pressing block 235 so that the micro-porous atomization sheet 234 is inclined downwards in the direction away from the water inlet end 2321. Correspondingly, the pressing block 235 is provided with a mist outlet 2351 matched with the micro-pore atomizing sheet 234, and atomized water generated by the micro-pore atomizing sheet 234 can move from the mist outlet 2351 to the mist cover 231 and is finally discharged through the storage opening. In this embodiment, the angle of inclination α of the microporous atomization sheet 234 is 15 ° to 30 °.

With continued reference to fig. 4 and 5, in order to ensure the water amount in the water inlet chamber 236, a water blocking edge 2352 and a water outlet hole 2361 are arranged at the high end of the pressing block 235 on the side away from the water inlet chamber 236, the water blocking edge 2352 extends around the mist outlet 2351 and towards the direction close to the mist outlet 2351, the water outlet hole 2361 is positioned at the side where the water blocking edge 2352 is away from the mist outlet 2351, and the water outlet hole 2361 is communicated with the water inlet chamber 236. After the inlet chamber 236 is filled, the excess water will flow out of the outlet 2361 and return to the water bottle 1 through the recycling hole 237.

With continued reference to fig. 4 and 5, to avoid deterioration and odor caused by the accumulation of water in the inlet chamber 236 for a long time, the mounting block 2322 is provided with a small hole 2362 communicating with the inlet chamber 236, and the small hole 2362 is located at the lower end of the inlet chamber 236. The apertures 2362 are small in size to allow only the water in the inlet chamber 236 to slowly permeate therethrough.

With continued reference to fig. 4 and 5, in order to increase the efficiency of discharging the atomized water, the mist seat 232 is provided with a blowing member 26 for blowing air into the mist seat 232. The air supply member 26 may be a fan or an air pump. The blowing member 26 blows air into the mist seat 232 to accelerate the air flow in the mist seat 232, so that the atomized water in the mist seat 232 can smoothly flow to the mist outlet end.

It should be noted that, in order to reduce energy consumption, the water supply member 24 can automatically supply water according to the actual water tank 22 in the water tank 22, and a control portion for controlling the opening and closing of the water supply member 24 may be disposed in the housing 21. Specifically, the tank 22 has a high level position and a low level position therein. The control section includes a high level sensor, a low level sensor and a controller 27. The high level sensor is disposed at a high level position of the water tank 22 and the end portion thereof extends into the water tank 22, and the low level sensor is disposed at a low level position of the water tank 22 and the end portion thereof extends into the water tank 22. The controller 27 is disposed within the housing 21.

The high level sensor senses the presence of water at a high level position in the tank 22 to output a high level detection signal, and the high level sensor is electrically connected to a first input of the controller 27 to transmit the high level detection signal to the controller 27. The low level sensor senses the presence or absence of water at a low level within the tank 22 to output a low level detection signal. The low level sensor is electrically connected to a second input of the controller 27 to provide a low level detection signal to the controller 27. The controller 27 is responsive to the high level detection signal and the low level detection signal to control the opening and closing of the water feed member 24. Specifically, when the water level in the water tank 22 is lower than the low liquid level position, the controller 27 controls the water feeding member 24 to be activated to feed water into the water tank 22, and when the water level in the water tank 22 is higher than the low liquid level position but lower than the high and low liquid level positions, the water feeding member 24 keeps an activated state to continue to feed water into the water tank 22 until the water level in the water tank 22 is higher than the high liquid level position, and the controller 27 controls the water feeding member 24 to be closed; the water in the water tank 22 gradually decreases toward the atomization assembly 23, when the water level in the water tank 22 is higher than the low liquid level position but lower than the high and low liquid level positions, the water feeding member 24 keeps a closed state, and the controller 27 controls the water feeding member 24 to start until the water level in the water tank 22 is lower than the low liquid level position; thereby, the water feeding member 24 is enabled to automatically supply water to stabilize the amount of water in the water tank 22, and the water feeding member 24 does not need to be always activated to reduce the power consumption of the micro-pore humidifying apparatus.

The implementation principle of the micropore humidifying device in the embodiment of the application is as follows: fill water in water bottle 1, then send water spare 24 to extract the water in the water bottle 1 via moisturizing pipe 3 to carry water to in the water tank 22, the water in the water tank 22 fills intake chamber 236 through damping tube 25 under the effect of self gravity, micropore atomizing piece 234 vibrations produce the atomizing water, the atomizing water leaves intake chamber 236 via a fog outlet 2351, air supply 26 starts to drive the atomizing water with higher speed and discharges from the fog end, thereby atomizes the humidification to the environment around this micropore humidifier 2.

The embodiments of the present invention are preferred embodiments of the present application, and the protection scope of the present application is not limited thereby, wherein like parts are denoted by like reference numerals. It should be noted that the terms "front," "back," "left," "right," "upper" and "lower" used in the following description refer to directions in the drawings, and the terms "inner" and "outer" refer to directions toward and away from, respectively, the geometric center of a particular component. Therefore, the method comprises the following steps: all equivalent changes made according to the structure, shape and principle of the present application shall be covered by the protection scope of the present application.

Claims

1. A micropore humidifying device comprises a water bottle (1) and a humidifier (2) arranged on the water bottle (1), a water replenishing pipe (3) communicated with the humidifier (2) is arranged in the water bottle (1), characterized in that the humidifier (2) comprises a shell (21), a water tank (22), an atomization component (23) and a water delivery piece (24), the shell (21) is connected with the water bottle (1), the water tank (22), the atomization assembly (23) and the water feeding piece (24) are all positioned in the shell (21), the water tank (22) is provided with a water replenishing end and a water guiding end, the water feeding piece (24) is communicated with the water replenishing pipe (3) and the water replenishing end of the water tank (22), the atomization assembly (23) is provided with a water inlet end (2321) and a mist outlet end, the water inlet end (2321) is communicated with the water guide end, and the height position of the water guide end is higher than that of the water inlet end (2321);

atomization component (23) including install in fog seat (232) of shell (21) with install in fog lid (231) of fog seat (232), it is located to intake end (2321) on fog seat (232), install the intercommunication in fog seat (232) intake nozzle (233) of end (2321), be provided with on nozzle (233) with micropore atomizing piece (234) that fog seat (232) are connected, the opening terminal surface slope of nozzle (233) sets up, micropore atomizing piece (234) with the opening of nozzle (233) corresponds the slope.

2. A microporous humidification device as claimed in claim 1 wherein the water conducting end is connected with a damping tube (25), the end of the damping tube (25) is connected with the water inlet end (2321).

3. A microporous humidification device as claimed in claim 1 wherein the microporous atomization sheet (234) is inclined away from the water inlet end (2321) and the angle of inclination α of the microporous atomization sheet (234) is 15 ° to 30 °.

4. A microporous humidification device according to claim 1, wherein the fog base (232) has a mounting table (2322) therein, the fog base (232) is mounted with a pressing block (235), an inlet chamber (236) is formed between the pressing block (235) and the bottom of the mounting table (2322), the nozzle (233) is located in the inlet chamber (236), and the microporous atomization sheet (234) is located on a surface of the pressing block (235) close to the nozzle (233).

5. A microporous humidification device as claimed in claim 4 wherein the briquetting (235) has a high end and a low end, the briquetting (235) is provided with a mist outlet (2351) matching with the microporous atomization sheet (234), the high end of the briquetting (235) far away from one side of the water inlet chamber (236) is provided with a water retaining edge (2352) and a water outlet hole (2361), the water retaining edge (2352) is wound around the mist outlet (2351), the water outlet hole (2361) is located on the side of the water retaining edge (2352) far away from the mist outlet (2351), and the water outlet hole (2361) is communicated with the water inlet chamber (236).

6. A microporous humidifying device as claimed in claim 5, characterized in that the bottom of the mist seat (232) is opened with a recovery hole (237), the recovery hole (237) is communicated with the water bottle (1).

7. A microporous humidification device as claimed in claim 4 wherein the mounting table (2322) is provided with a small hole (2362) communicating with the inlet chamber (236), the small hole (2362) is located at the lower end of the inlet chamber (236).

8. A microporous humidifying device according to claim 1, characterized in that the mist seat (232) is provided with a blowing member (26) for blowing air into the mist seat (232).

9. A microporous humidification device as claimed in claim 1 wherein the water tank (22) has a high liquid level and a low liquid level, the housing (21) has a control part for controlling the water supply member (24) to open and close, the control part comprises:

the high liquid level sensor is arranged at the high liquid level position of the water tank (22) and senses whether water at the high liquid level position in the water tank (22) exists or not so as to output a high liquid level detection signal;

the low liquid level sensor is arranged at the low liquid level position of the water tank (22) and senses whether water at the low liquid level position in the water tank (22) exists or not so as to output a low liquid level detection signal;

the controller (27) is arranged in the shell (21), and the controller (27) responds to a high liquid level detection signal and a low liquid level detection signal to control the opening and closing of the water feeding piece (24).