阅读说明：本技术 一种用于提高生鲜食品货架期的等离子体装置 (Plasma device for prolonging shelf life of fresh food ) 是由 梅丹华 张鹏 陈慧敏 刘诗筠 方志 于 2021-08-18 设计创作，主要内容包括：本发明提供了一种用于提高生鲜食品货架期的等离子装置,柜体中设有载物台,载物台被透明玻璃罩盖住,透明玻璃罩内上方设有轨道,移动处理罩在轨道上移动,移动处理罩包括罩体和连接端,连接端和轨道连接,连接端上端侧边设有进风口、顶端设有进线孔,进风口通过气道和风机连接,罩体内壁设有柔性电极,柔性电极和高压电源模块连接,高压线和低压线通过进线孔进入到罩体和柔性电极连接。本发明可以以直接和间接方式对生鲜食品进行杀菌处理,不消耗任何惰性气体,直接在空气中产生低温等离子体,柔性电极提高了等离子体的均匀性；另外,考虑了对尾气的吸收,增加了对生鲜上可能附带废液的回收装置,半衰期较长的活性粒子可对废液进行杀菌消毒。(The invention provides a plasma device for improving the shelf life of fresh food, wherein an object stage is arranged in a cabinet body, the object stage is covered by a transparent glass cover, a track is arranged above the inside of the transparent glass cover, a movable processing cover moves on the track, the movable processing cover comprises a cover body and a connecting end, the connecting end is connected with the track, the side edge of the upper end of the connecting end is provided with an air inlet, the top end of the connecting end is provided with a wire inlet hole, the air inlet is connected with a fan through an air passage, the inner wall of the cover body is provided with a flexible electrode, the flexible electrode is connected with a high-voltage power supply module, and a high-voltage wire and a low-voltage wire enter the cover body through the wire inlet hole and are connected with the flexible electrode. The invention can sterilize fresh food in direct and indirect modes, does not consume any inert gas, directly generates low-temperature plasma in the air, and improves the uniformity of the plasma by the flexible electrode; in addition, the absorption to tail gas has been considered, has increased the recovery unit to the subsidiary waste liquid of probably going up living fresh, and the longer active particle of half-life period can disinfect the disinfection to the waste liquid.)

1. The utility model provides a plasma device for improving give birth to bright food shelf life, includes the cabinet body (13), be equipped with objective table (3) in the cabinet body (13), objective table (3) are covered its characterized in that by clear glass cover (2): the upper side is equipped with track (1) in transparent glass cover (2), removes to handle cover (8) and moves on track (1), it includes the cover body (8-1) and link (8-2) to remove to handle cover (8), link (8-2) with track (1) are connected, link (8-2) upper end side is equipped with air intake (702), the top is equipped with entrance hole (801), air intake (702) are connected with fan (11) through air flue (9), the cover body (8-1) inner wall is equipped with flexible electrode (804), flexible electrode (804) and high voltage power supply module (12) are connected, and high-voltage line and low-voltage line enter into the cover body (8-1) and are connected with flexible electrode (804) through entrance hole (801).

2. The plasma apparatus for improving the shelf life of fresh food as claimed in claim 1, wherein: the track (1) comprises two fixing surfaces (1-1) arranged on two sides of the top in a transparent glass cover (2), each fixing surface (1-1) comprises a first surface connected with the top of the transparent glass cover (2) and a bottom surface provided with a first track (1-2), the two sides of the first surface and the bottom surface are connected through a second surface, a pulley frame (1-4) is further arranged, each pulley frame (1-4) comprises two pulleys (401) and a support (404), the first pulleys (401) are connected with the first tracks (1-2) and can slide back and forth on the first tracks (1-2), each support (404) is connected with a support interface (301) corresponding to a movable track (1-3), the top of the movable processing cover (8) is connected with the movable tracks (1-3) through U-shaped pulley frames (1-5), the U-shaped pulley frame (1-5) comprises a second pulley (501), and the second pulley (501) is connected with the movable track (1-3) and can slide left and right on the second track (302) of the movable track (1-3).

3. The plasma apparatus for improving the shelf life of fresh food as set forth in claim 1 or 2, wherein: the connecting end (8-2) is a telescopic moving pipe, a steel wire rope is arranged on the telescopic moving pipe, and the length of the telescopic moving pipe is adjusted by pulling the steel wire rope up and down.

4. The plasma apparatus for improving the shelf life of fresh food as set forth in claim 1 or 2, wherein: the flexible electrode (804) comprises multiple layers, and a first insulating layer (8041), a metal electrode layer (8042), a second insulating layer (8043), a metal layer (8044) and a third insulating layer (8045) are arranged from top to bottom, wherein a high-voltage metal electrode strip (8046) on the first insulating layer (8041) is used for connecting the metal electrode layer (8042) with a high-voltage line, and a low-voltage metal electrode strip (8048) on the second insulating layer (8045) is used for connecting the metal layer (8044) with a low-voltage line.

5. The plasma apparatus for improving the shelf life of fresh food as claimed in claim 4, wherein: the metal electrode layer (8042) is characterized in that hexagons with the same copper engraving side length on the front side are uniformly and alternately arranged, and copper is fully paved on the back side.

6. The plasma apparatus for improving the shelf life of fresh food as claimed in claim 4, wherein: the bending angle of the flexible electrode (804) is changed within the range of 0-170 degrees, wherein the metal electrode layer (8042) and the metal layer (8044) are always kept parallel to each other.

7. The plasma device for improving the shelf life of fresh food as claimed in any one of claims 1 to 2 and 5 to 6, wherein: the utility model discloses an article table, including objective table (3) below, activated carbon device (5) are fixed on the cabinet body (11) including stationary plane (503) and through stationary plane (503), the shell of activated carbon device (5) includes first micropore face (501) and second micropore face (502), the unilateral of first micropore face (501) can be opened and closed, and second micropore face (502) are facing to water course (4), and the waste liquid enters into through water course (4) in waste liquid collection box (6) of activated carbon device (5) below.

8. The plasma apparatus for improving the shelf life of fresh food as claimed in claim 7, wherein: the waste liquid recovery box (6) comprises a water inlet (601) and a waste liquid storage box (603), and waste liquid enters the waste liquid storage box (603) from the water inlet (601).

9. The plasma apparatus for improving the shelf life of fresh food as claimed in claim 8, wherein: the waste liquid storage tanks (603) are symmetrically arranged, a transparent pull ring (602) is arranged on each waste liquid storage tank (603), and the transparent pull ring (602) is arranged on one side facing outwards.

10. The plasma apparatus for improving the shelf life of fresh food as claimed in any one of claims 1 to 2, 5 to 6, and 8 to 9, wherein: the high-voltage power supply module (12) and the fan (11) are arranged in the cabinet body (13).

Technical Field

The invention relates to a device for improving the shelf life of fresh food, in particular to a plasma device for improving the shelf life of the fresh food.

Background

The fresh food is fresh agricultural product which is formed by planting, picking, culturing and catching, is not processed or is primarily processed and can be eaten by human beings. Livestock and poultry are the main sources of meat in 'fresh three-product fruits and vegetables, aquatic products and meat' and are also the main sources of protein ingested by human beings. Due to the unique nutritional ingredients, high water activity and moderate pH, meats and meat products are good growth media for a variety of microorganisms and are identified as common carriers for food-borne diseases. Spoilage bacteria can cause degradation of proteins, carbohydrates, fats and other components, resulting in off-flavors, discoloration, pH changes, mucus formation and meat softening, thereby greatly reducing the shelf life of the product. More seriously, eating meat products contaminated with pathogenic bacteria may induce serious food-borne diseases and even death, causing serious health problems and economic losses. How to continuously and effectively inactivate bacteria on the fresh surface is the key to prolonging the shelf life of the fresh food.

The plasma is the fourth state of matter, and is considered to be a novel molecular activation means by virtue of the fact that the system contains a large amount of active components such as high-energy electrons, ions, excited-state atoms, free radicals and the like. The atmospheric pressure low-temperature plasma is a non-equilibrium plasma generated by utilizing gas discharge under the atmospheric pressure condition, and because the electron temperature in the system is far higher than the temperature of heavy particles, the high chemical activity can be obtained while the gas temperature close to room temperature is maintained, and the atmospheric pressure low-temperature plasma is taken as an efficient dry process link and is widely applied to the fields of material surface modification, environmental protection, new energy preparation, food sterilization and disinfection and the like.

The publication numbers CN111671055A, CN112263115A and CN112586713A disclose traditional technical means such as ultraviolet sterilization and drug soaking, which, although inhibiting the diffusion and deterioration of bacteria to some extent, still need to be improved in terms of drug permeability, sterilization efficiency and convenience of use, and have a certain gap from the realization of complete inactivation of bacteria.

The patent publication nos. CN110731367A, CN110959661A and CN109006966A disclose that atmospheric low-temperature plasma is used for direct sterilization, and although research and practice have proved that it has positive effects in sterilization, disinfection and shelf life extension, the direct effect may cause certain damage to some heat-sensitive fresh foods, and affect the quality of the fresh foods.

Patent publication nos. CN211241514U, CN110235932A, and CN110731368A disclose indirect sterilization methods using plasma, and although the electrode structure using the indirect sterilization method is more flexible and suitable for heat-sensitive fresh food, the sterilization effect is far inferior to that of direct sterilization due to less active particles in indirect sterilization, and the same sterilization rate as that of direct sterilization cannot be ensured.

Patent publication nos. CN110897077A, CN111470593A and CN110734112A disclose methods for sterilizing activated water using plasma, which can satisfy the surface treatment requirements of objects of different shapes and provide favorable conditions for the diffusion of active particles into the deep part of the fresh food, but the plasma activated water is difficult to treat large-area and large-batch fresh food, generates a large amount of waste water, and partially cannot be soaked in water.

Disclosure of Invention

1. The technical problem to be solved is as follows:

effectively prolong the shelf life of fresh food.

2. The technical scheme is as follows:

in order to solve the problems, the invention provides a plasma device for improving the shelf life of fresh food, which comprises a cabinet body, wherein an object stage is arranged in the cabinet body, the object stage is covered by a transparent glass cover, a rail is arranged above the inside of the transparent glass cover, a movable processing cover moves on the rail, the movable processing cover comprises a cover body and a connecting end, the connecting end is connected with the rail, an air inlet is arranged on the side edge of the upper end of the connecting end, a wire inlet hole is arranged at the top end of the connecting end, the air inlet is connected with a fan through an air passage, a flexible electrode is arranged on the inner wall of the cover body, the flexible electrode is connected with a high-voltage power supply module, and a high-voltage wire and a low-voltage wire enter the cover body through the wire inlet hole and are connected with the flexible electrode.

The track includes that two stationary planes establish the both sides at the top in transparent glass cover, every the stationary plane includes the first face of being connected with transparent glass cover top and sets up first orbital bottom surface, the both sides of first face and bottom surface are passed through the second face and are connected, still are equipped with the pulley yoke, the pulley yoke includes two pulleys and support, first pulley with first track is connected to can slide around on first track, every the support interface connection that support and portable track correspond, U type pulley yoke and portable track connection are passed through to the top of cover are handled in the removal, U type pulley yoke includes the second pulley, second pulley and portable track connection to can be on portable orbital second track horizontal slip.

The connecting end is a telescopic moving pipe, a steel wire rope is arranged on the telescopic moving pipe, and the length of the telescopic moving pipe is adjusted by pulling the steel wire rope up and down.

The flexible electrode comprises a plurality of layers, wherein a first insulating layer, a metal electrode layer, a second insulating layer, a metal layer and a third insulating layer are arranged from top to bottom, a high-voltage metal electrode strip on the first insulating layer is used for connecting the metal electrode layer and a high-voltage wire, and a low-voltage metal electrode strip on the second insulating layer is used for connecting the metal layer and a low-voltage wire.

And hexagons with the same copper engraving side length on the front side of the metal electrode layer are uniformly and alternately arranged, and copper is fully paved on the back side of the metal electrode layer.

The bending angle of the flexible electrode is changed within the range of 0-170 degrees, wherein the metal electrode layer and the metal layer are always kept parallel to each other.

The objective table below is equipped with the active carbon device, the active carbon device includes the stationary plane and fixes on the cabinet body through the stationary plane, the shell of active carbon device includes first micropore face and second micropore face, the unilateral of first micropore face can be opened and closed, and the second micropore face is facing to the water course, and the waste liquid enters into through the water course in the waste liquid recovery case of active carbon device below.

Waste liquid recovery case includes water inlet and waste liquid bin, and the waste liquid is followed the water inlet gets into the waste liquid bin.

The waste liquid bin has two, and the symmetry is placed, is provided with transparent pull ring on every waste liquid bin, transparent pull ring is placed in one side outwards.

The high-voltage power supply module and the fan are arranged in the cabinet body.

3. Has the advantages that:

the invention can directly generate low-temperature plasma in the air without consuming any inert gas, thereby improving the economy of the fresh shelf life. Compared with the existing plasma sterilization method, when the shelf life of the fresh food is prolonged by adopting the method, the uniformity of the plasma generated on the surface of the medium is improved and the safety of the plasma to the fresh food is ensured due to the adoption of the flexible printed circuit board technology, and in addition, the structure of the surface dielectric barrier discharge reactor is convenient to install, disassemble and replace. When the method is adopted to prolong the shelf life of the fresh food, because the mode of combining direct action and indirect action is considered, different action modes can be selected according to application objects, the distance between the flexible electrode and the surface of the fresh food is adjusted by using the telescopic moving pipe to change the plasma intensity and the active particle concentration acting on the surface of the fresh food, and the flexibility of sterilization of the fresh food is enhanced. Adopt this device when considering giving birth to bright shelf life, not only considered the absorption to tail gas, still increased the waste liquid recovery unit and retrieved the perhaps subsidiary waste liquid of giving birth to on the bright, the longer active particle of half-life period that low temperature plasma produced in addition can disinfect the disinfection to the waste liquid.

Drawings

FIG. 1 is a schematic view of the apparatus of the present invention.

Fig. 2 is a schematic structural diagram of a track.

Fig. 3 is a schematic structural view of the pulley frame.

Fig. 4 is a schematic view of the engagement of the movable process shield and the movable rail.

Fig. 5 is a schematic diagram of a movable track structure.

Fig. 6 is a schematic structural view of a U-shaped pulley yoke.

Fig. 7 is a schematic view of the structure of the movable processing hood.

Fig. 8 is a schematic structural view of an activated carbon device.

FIG. 9 is a schematic view of the structure of the waste liquid recovery apparatus.

FIG. 10 is a schematic diagram of a second embodiment of a moveable processing chamber.

Fig. 11 is a schematic diagram of a flexible electrode structure layer.

Fig. 12 is a schematic front and back view of a flexible electrode.

FIG. 13 is a graph showing the bactericidal effect of Escherichia coli.

FIG. 14 is a table showing the number of E.coli colonies as a function of sterilization time.

FIG. 15 is a graph comparing the direct and indirect bactericidal effect of E.coli.

Description of reference numerals: 1. a track; 2, a transparent glass cover; 3. an object stage; 4. a water channel; 5. an activated carbon device; 6. a waste liquid recovery device; 7. a glass cabinet door; 8. a movable process shield; 9. an airway; 10. an air inlet; 11. a fan; 12. a high voltage power supply module; 13. a cabinet body; 1-1, a fixed surface, 1-2, a first track; 1-3. a movable track; 1-4 pulley frames, 1-5U-shaped pulley frames, 1-6 trachea brackets; 301 a cradle interface; 302. a second track; 401. a pulley; 404. a support; 501. a first microporous surface; 502. a second microporous surface; 503. a fixed surface; 601. a water inlet; 602. a transparent circular pull ring; 603. a waste liquid storage tank; 702. an air inlet; 901. a main pipe; 902. a branch pipe; 903. a branch pipe; 8-1. a cover body; 8-2, connecting end; 801. a wire inlet hole; 804. a flexible electrode; 8041. a first insulating layer; 8042. a metal electrode layer; 8043. a second insulating layer; 8044 a metal layer; 8045. a third insulating layer; 8046. a metal electrode strip; 8047. a hexagon; 8048. a metal electrode strip.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings.

As shown in fig. 1, a plasma device for improving the shelf life of fresh food, comprises a cabinet body 13, wherein an object stage 3 is arranged in the cabinet body 13, the object stage 3 is covered by a transparent glass cover 2, a track 1 is arranged above the transparent glass cover 2, a movable processing cover 8 moves on the track 1, and the track 1 can allow the movable processing cover 8 to move freely in the transparent glass cover 2 and stop at any position.

As shown in fig. 7 and 10, the mobile processing cover 8 includes a cover body 8-1 and a connection end 8-2, the connection end 8-2 is connected to the rail 1, an air inlet 702 is disposed on a side edge of an upper end of the connection end 8-2, a wire inlet hole 801 is disposed at a top end of the connection end 8-2, the air inlet 702 is connected to the blower 11 through the air duct 9, a flexible electrode 804 is disposed on an inner wall of the cover body 8-1, the flexible electrode 804 is connected to the high voltage power module 12, and a high voltage wire and a low voltage wire enter the cover body 8-1 through the wire inlet hole 801 and are connected to the flexible electrode 804.

The movable processing cover 8 slides on the track 1 to the position above the fresh food, the flexible electrode 804 is electrified, plasma discharges, nitrogen, oxygen and a small amount of water vapor in the air can be ionized near the flexible electrode, and rich OH and H can be generated₂O₂、HO₂、O₃NO and N₂And O active particles which are diffused to the surface of the fresh food can be used for inactivating bacteria and prolonging the shelf life of the fresh food.

In one embodiment, the fan 11 is turned on while the flexible electrode 804 is powered on to perform plasma discharge, air enters the guest mobile processing cover 8 from the air inlet 702, and the flexible electrode 804 generates active substances to sterilize the fresh surface under the driving of the fan 11. And the user can make corresponding adjustment to the processing mode according to the fresh volume, the shape, the heat sensitivity and the like.

As shown in fig. 2-6, the track 1 comprises two fixing surfaces 1-1 arranged on two sides of the top in the transparent glass cover 2, each fixing surface 1-1 comprises a first surface connected with the top of the transparent glass cover 2 and a bottom surface provided with a first track 1-2, the two sides of the first surface and the bottom surface are connected through a second surface, a pulley frame 1-4 is further arranged, the pulley frame 1-4 comprises two pulleys 401 and a bracket 404, the first pulley 401 is connected with the first track 1-2 and can slide back and forth on the first track 1-2, each bracket 404 is connected with a corresponding bracket interface 301 of the movable track 1-3, the top of the movable treatment cover 8 is connected with the pulley frame 1-4 through a U-shaped pulley frame 1-5 and the movable track 1-3 to slide in the first track 1-2, the movable rails 1-3 are driven to slide, thereby driving the movable processing cover 8 to slide back and forth.

The U-shaped pulley frame 1-5 includes a second pulley 501, and the second pulley 501 is connected to the movable rail 1-3 and can slide left and right on the second rail 302 of the movable rail 1-3, so as to drive the movable processing hood 8 to slide left and right.

In one embodiment, the connecting end 8-2 is a telescopic moving pipe, a steel wire rope is arranged on the telescopic moving pipe, and the length of the telescopic moving pipe is adjusted by pulling the steel wire rope up and down. This kind of structure can be through adjusting the distance of portable processing cover 8 and giving birth to bright food, at flexible electrode 804 discharge process, adjusts flexible removal pipe 802 to cover giving birth to bright the messenger flexible electrode 804 to portable processing cover 8 and close to giving birth to bright completely. The movable processing hood 8 covers the fresh food to form a relatively closed processing space, and active ingredients in the plasma are prevented from being dissipated. Under the effect that the fan 11 passes through the air, can be according to giving birth to bright volume, shape and heat sensitivity etc. change the distance of flexible electrode 804 to giving birth to bright surface, can adjust the concentration of these active particle effects and giving birth to bright, realize the sterilization of different intensity and reduce the temperature rise on giving birth to bright surface.

The concentration of the active particles can be adjusted by changing the electrical parameters of the high-voltage power supply module 12, so that sterilization treatment with different intensities can be realized. In addition, in the sterilization process, the plasma sterilization effect can be adjusted by regulating and controlling the parameters of the high-voltage power supply module 12. The voltage waveform, the voltage amplitude and the voltage frequency output by the high-voltage power supply module 12 can be changed by a user according to the fresh volume, the shape, the heat sensitivity and the like to regulate the discharge intensity and the plasma density. The user can also change high frequency alternating voltage into intermittent type formula alternating voltage, reduces the temperature rise on flexible plasma device and the fresh surface, suitably reduces plasma's sterilization rate. In addition, if the user changes high frequency alternating voltage into microsecond impulse voltage or nanosecond impulse voltage, can reduce the temperature rise on device and the fresh surface on the basis of improving the sterilization rate.

In one embodiment, as shown in fig. 11 to 12, the flexible electrode 804 includes multiple layers, from top to bottom, a first insulating layer 8041, a metal electrode layer 8042, a second insulating layer 8043, a metal layer 8044 and a third insulating layer 8045, wherein a high-voltage metal electrode strip 8046 on the first insulating layer 8041 is used for connecting the metal electrode layer 8042 and a high-voltage line, and a low-voltage metal electrode strip 8048 on the second insulating layer 8045 is used for connecting the metal layer 8044 and a low-voltage line.

Repeated side-length hexagons 8047 are etched on the metal electrode layer 8042 with copper. This pattern covers a surface with a minimum total perimeter and allows atmospheric plasma to be generated along the edges of the hexagonal grid. In order to ensure the uniformity of the plasma generated on the surface of the metal electrode layer 8042, the hexagons on the metal electrode layer 8042 are uniformly staggered. The pad is opened with copper for connecting high voltage and low voltage electrodes, wherein the high voltage metal electrode strip 8046 on the first insulating layer 8041 is used for connecting the high voltage electrode 8042 and a high voltage line, and the low voltage metal electrode strip 8048 on the third insulating layer 8045 is used for connecting the low voltage electrode 8044 and a low voltage line. The black areas of the metal electrode layer 8042 and the metal layer 8044 are fully coated with copper.

The first insulating layer 8041, the metal electrode layer 8042, the second insulating layer 8043, the metal layer 8044, and the third insulating layer 8045 all have excellent flexibility, and the bending angle varies within a range of 0 to 170 °. No matter how the flexible electrode is bent, the high-voltage metal electrode layer 8042 and the low-voltage metal electrode layer 8044 are always parallel to each other, so that the flexible plasma device can discharge uniformly all the time.

In one embodiment, an average bacteria count of 294 × 10 is selected⁶The Escherichia coli culture solution was subjected to a sterilization test. The Escherichia coli is subjected to a treatment voltage of 5 kV,the frequency is 3 kHz, the treatment time is 0-30 s, and the sterilization effect of the Escherichia coli is shown in figure 13. It can be seen from table 1 of fig. 14 that the direct treatment bactericidal effect varies significantly between 5 and 10 s, and the number of escherichia coli colonies is sporadically present by 10 s. The sterilization effect of the plasma active substance generated by the flexible electrode on the escherichia coli is more obvious.

In one embodiment, an average bacteria count of 294 × 10 is selected⁶The Escherichia coli culture solution was subjected to a sterilization test. The Escherichia coli was treated at a treatment voltage of 5 kV and a frequency of 3 kHz for 30 s, and the bactericidal effect of the Escherichia coli was as shown in FIG. 15. It can be observed from fig. 15 that the number of colonies of escherichia coli after indirect treatment is significantly reduced, which indicates that the sterilization effect of the plasma active substance generated by the flexible electrode indirect method on escherichia coli is significant, and the flexible electrode indirect method can be used for fresh sterilization.

In one embodiment, an activated carbon device 5 is arranged below the object stage 2, the activated carbon device 5 comprises a fixing surface 503 and is fixed on the cabinet body 11 through the fixing surface 503, a shell of the activated carbon device 5 comprises a first microporous surface 501 and a second microporous surface 502, one side of the first microporous surface 501 can be opened and closed, the second microporous surface 502 faces the water channel 4, and waste liquid enters a waste liquid recovery box 6 below the activated carbon device 5 through the water channel 4.

When the fan 11 drives the gas in the glass to flow, the gas enters the activated carbon device through the micropores with the diameter of 2 mm in the first micropore surface 501 and the second micropore surface 502, and the activated carbon adsorbs the waste gas. The first microporous surface 501 is switchable on one side for filling and replacing activated carbon particles. The upper half of the second microporous surface 502 corresponds to the outlet of the water tank in the water channel 4, and the waste liquid is purified by activated carbon and then flows into the waste liquid recovery device 6 from the lower part. The activated carbon device is fixed on the cabinet 13 by the fixing surface 503.

In one embodiment, the waste recovery tank 6 includes a water inlet 601 and a waste storage tank 603, and waste enters the waste storage tank 603 from the water inlet 601. The transparent circular pull ring 602 facilitates replacement of the waste liquid recovery device and observation of the level of waste liquid in the waste liquid recovery device. The waste liquid storage tanks 603 are symmetrically arranged, each waste liquid storage tank 603 is provided with a transparent pull ring 602, and the transparent pull rings 602 are arranged on one side facing outwards.

Although the present invention has been described with reference to the preferred embodiments, it should be understood that various changes and modifications can be made therein by those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.