CN111054567A

CN111054567A - Protein water solution spraying equipment

Info

Publication number: CN111054567A
Application number: CN201911335272.6A
Authority: CN
Inventors: 吉训明; 高原; 李明; 尹志臣; 丁玉川; 鲍路姿; 姜缪文; 李思颉; 吴隆飞; 吴川杰
Original assignee: Suzhou Innovation Research Institute Of Beijing University Of Aeronautics And Astronautics; Xuanwu Hospital
Current assignee: Suzhou Innovation Research Institute Of Beijing University Of Aeronautics And Astronautics; Xuanwu Hospital
Priority date: 2019-12-23
Filing date: 2019-12-23
Publication date: 2020-04-24
Anticipated expiration: 2039-12-23
Also published as: CN111054567B

Abstract

The invention relates to the field of biomedical material processing and preparation, and provides a protein-based aqueous solution spraying equipment. The spraying equipment comprises a sealed tank, a humidity adjustment device and a first temperature adjustment device are arranged on the sealed tank, a liquid storage tank and a spraying equipment are arranged in the sealed tank, and a first filter screen and a second temperature adjustment device are arranged on the liquid storage tank , the sealing tank is provided with a first driving device; the spraying device includes a spray head and a second driving device. The application ensures that the storage and spraying process of the protein aqueous solution are in a constant temperature and humidity environment, and a small amount of denatured protein is filtered out through the first filter screen to avoid the phenomenon of nozzle blockage. The inorganic material is separated to ensure the spraying effect. At the same time, the protein aqueous solution is evenly sprayed on the sample through the nozzle to ensure the smoothness of the coating surface. Floor.

Description

Protein aqueous solution spraying equipment

Technical Field

The invention relates to the field of biomedical material processing and preparation, in particular to a protein aqueous solution spraying device.

Background

The silk fibroin is extracted from silk or spider silk, has wide source, convenient and diverse processing, and excellent mechanical property, biocompatibility and biodegradability of the product. The silk fibroin is easy to denature under the influence of temperature, humidity, stress and concentration, so that the preparation method of the coating is limited. The silk fibroin film is usually prepared by sol-gel method, spin coating method, coating-evaporation method, etc.

Due to the changeability of silk fibroin, basically all the coating methods of silk fibroin coatings are biased to simply coat the silk fibroin aqueous solution on the surface of a sample. However, these methods inevitably have several disadvantages: (1) firstly, the film layer is not easy to accurately control the thickness due to the adoption of the modes of coating, casting, soaking and the like, and the film layer obtained by the method is easy to crack and fall off; (2) if the vertical lifting mode is adopted for dip coating, the uniform coverage of the coating is difficult to achieve due to the influence of gravity and the surface tension of the liquid; (3) because the coating raw material is liquid and directly contacts the surface of the sample, the coating raw material is difficult to achieve finer texture, and meanwhile, the coating raw material is remained on the surface of the sample by depending on the viscosity of the liquid, and the defects can be further amplified in the coating process aiming at the unconventional plane sample; (4) the coating solution is easily influenced by temperature and humidity, and is easy to generate a gel phenomenon in the using or storing process, so that the preparation efficiency is reduced; (5) in the forming stage of the coating, the water evaporation of the silk fibroin solution sprayed on is slow, the natural airing takes long time, and the silk fibroin solution is not suitable for mass production.

Spraying is a common coating preparation technology and is widely applied in industry, but in spraying of a silk fibroin coating, the silk fibroin solution is influenced by temperature, humidity and drastic airflow change in a spray gun, so that the silk fibroin structure is easily changed, flocculent precipitates or gel substances are generated, and liquid stored in a spray gun tank is often denatured into gel due to the influence of humidity and temperature, so that pipelines are blocked. Meanwhile, when an inorganic material is added into the silk fibroin solution to realize a specific function, the inorganic material and the silk fibroin solution are fused in a physical state, so that the inorganic material is separated from the silk fibroin solution under long-time precipitation, and the obtained coating cannot achieve the expected effect.

Disclosure of Invention

In order to solve the above technical problems or at least partially solve the above technical problems, the present invention provides a protein-based aqueous solution spraying apparatus.

Above-mentioned protein class aqueous solution spraying equipment includes the seal pot, is equipped with humidity control device and a temperature regulation apparatus on the seal pot, is equipped with in the seal pot:

the liquid storage tank comprises a feed inlet for water solution to enter, a first filter screen is arranged in the liquid storage tank along the cross section direction of the inflow of the water solution, a second temperature adjusting device is arranged on the liquid storage tank, and a first driving device for driving the liquid storage tank to reciprocate is arranged on the sealing tank so as to enable the water solution to shake;

the spraying equipment comprises a spray head and second driving equipment, wherein the spray head is used for spraying the aqueous solution in the liquid storage tank towards the direction of the sample, and the second driving equipment is used for driving the spray head to move along the length direction of the sample.

Optionally, the first driving device comprises:

the driving plate is hinged on the liquid storage tank and connected with the liquid storage tank, and a hinge shaft of the driving plate is superposed with the central line;

the first driving mechanism comprises two first electric push rods symmetrically arranged along the hinge shaft, one end of each first electric push rod is arranged on the inner wall of the sealing tank, the other end of each first electric push rod is hinged with the driving plate, and the two first electric push rods are perpendicular to the driving plate in a natural state.

Optionally, the second driving device comprises:

the first slideway is arranged along the length direction of the sample, and a first base for placing a spray head is arranged on the first slideway;

and the second driving mechanism is used for driving the first base to move along the length direction of the first slide way.

Optionally, the first slide includes a first screw rod and a guide rod arranged along the length direction of the sample, the first base is provided with a through hole in sliding fit with the guide rod and a first screw hole matched with the first screw rod, and the second driving mechanism includes a motor for driving the first screw rod to rotate.

Optionally, the spray head is hinged to the first base, so that the spray head can swing along a direction perpendicular to the first slideway.

Optionally, the spraying device further comprises a third driving device, the third driving device comprises two second slides arranged in parallel, second bases are arranged on the two second slides in a sliding mode, two ends of the first slide are arranged on the two second bases respectively, and a third driving mechanism used for driving the second bases to slide is arranged on one of the second slides, so that the first slide is close to or far away from the sample.

Optionally, one of the second sliding ways is a second screw rod, a second screw hole matched with the second screw rod is formed in the second base, and the third driving mechanism comprises a motor for driving the second screw rod to rotate.

Optionally, the liquid storage tank is arranged along the vertical direction, and the liquid level of the aqueous solution in the liquid storage tank is higher than the first filter screen.

Alternatively, after the aqueous solution mixed with the inorganic material is precipitated, the position of the first filter may be adapted to the position where the aqueous solution and the inorganic material are separated.

Optionally, a second filter screen is arranged in the liquid storage tank, the second filter screen is arranged between the first filter screen and the feed inlet, and the aperture of the first filter screen is smaller than that of the second filter screen.

Compared with the prior art, the technical scheme provided by the embodiment of the application has the following advantages:

this application guarantees that the storage of protein class aqueous solution and spraying process are all in constant temperature and humidity environment, reduce the conversion rate of protein, filter a small amount of denatured protein through first filter screen simultaneously, avoid appearing the phenomenon that the shower nozzle blockked up, rock through the liquid storage pot, avoid protein class aqueous solution and inorganic material separation, make the mixture more even, ensure the spraying effect, and simultaneously, evenly spray protein class aqueous solution on the sample through the shower nozzle, increase spraying efficiency, ensure the planarization on coating surface, and can change the thickness of coating according to shower nozzle reciprocating motion's number of times, obtain the coating that satisfies the demand.

Drawings

FIG. 1 is a schematic view of an apparatus for spraying an aqueous protein solution according to an embodiment of the present invention;

fig. 2 is a schematic view of a spray coating device in an embodiment of the present invention.

Reference numerals:

1. sealing the tank; 11. a humidity adjusting device; 12. a first temperature adjustment device; 2. a liquid storage tank; 21. a first filter screen; 22. a second temperature adjustment device; 23. a second filter screen; 3. a spray head; 31. an air pump; 4. a drive plate; 41. hinging a shaft; 42. a first electric push rod; 5. a first lead screw; 51. a guide bar; 52. a first base; 6. a second slideway; 61. a second base; 62. and a second screw rod.

Detailed Description

In order that the above objects, features and advantages of the present invention can be more clearly understood, the present invention will be further described in detail with reference to the accompanying drawings and examples. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. The specific embodiments described herein are merely illustrative of the invention and are not to be construed as limiting the invention. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the invention, are within the scope of the invention.

As shown in fig. 1, the protein aqueous solution spraying apparatus provided in the embodiment of the present application includes a sealed tank 1, and a humidity control device 11 and a first temperature control device 12 are provided on the sealed tank 1. Humidity control device 11 can set up on the outer wall of seal pot 1, through the inside intercommunication of pipeline with seal pot 1, through the inside humidity of humidity control device 11 regulation seal pot 1, and can guarantee the inside and outside pressure balance of seal pot 1. The first temperature adjusting device 12 is provided on the inner wall of the hermetic vessel 1, and its specific installation position is not limited, and the temperature inside the hermetic vessel 1 is adjusted by the first temperature adjusting device 12. The humidity and the temperature of the inner space of the sealing tank 1 are changed through the humidity adjusting device 11 and the first temperature adjusting device 12, so that the requirement for conventional storage of protein is met, the sealing tank 1 is sealed, the inner constant temperature and humidity are realized, and the phenomenon of denaturation of the protein is avoided. A liquid storage tank 2 and spraying equipment are arranged in the sealed tank 1, wherein the liquid storage tank 2 is used for introducing or storing aqueous solution, and the spraying equipment is used for spraying the aqueous solution in the liquid storage tank 2 to form a coating on the surface of a sample. The sealing of the sealing can 1 does not mean that the sealing can 1 cannot be opened, but means that after the liquid storage tank 2, the spraying equipment and other devices are placed in the sealing can 1, the opening of the sealing can 1 is closed, and then the internal space and the external space of the sealing can 1 are isolated.

The liquid storage tank 2 comprises a feed inlet through which water solution can enter, wherein the feed inlet is an opening formed in the liquid storage tank 2, the water solution enters the liquid storage tank 2 through the feed inlet, the opening is convenient for keeping the pressure balance between the inside of the liquid storage tank 2 and the sealing tank 1, and spraying equipment is convenient for spraying the water solution in the liquid storage tank 2. The aqueous solution may be an aqueous solution of a protein or an aqueous solution of a protein to which an inorganic material is added. The first filter 21 is disposed in the reservoir 2 along a cross-sectional direction of the inflow of the aqueous solution, and the cross-sectional direction is perpendicular to a flow direction of the aqueous solution, so that a small amount of denatured protein can be filtered by the first filter 21. The second temperature adjusting device 22 is arranged on the liquid storage tank 2, the second temperature adjusting device 22 is arranged on the side wall of the liquid storage tank 2, the temperature in the liquid storage tank 2 is controlled through the second temperature adjusting device 22, and the phenomenon of protein denaturation is avoided. Be equipped with on the seal pot 1 and be used for driving liquid storage pot 2 and make reciprocating motion's first drive arrangement to make aqueous solution rock, make the aqueous solution in the seal pot 1 be in the state of rocking all the time, avoid aqueous solution and inorganic material separation.

The spraying apparatus includes a head 3 for spraying the aqueous solution in the reservoir 2 toward the sample. Specifically, the spray head 3 is connected with the liquid storage tank 2 through a pipeline, an air pump 31 is arranged on the outer side of the seal tank 1, the spray head 3 is connected with the air pump 31 through a pipeline, and the air pump 31 conveys air flow towards the spray head 3 through a pipeline. When the device is used, the air pump 31 generates high-pressure air to flow into the spray head 3, the air flowing at high speed generates low pressure at the spray head 3, and the aqueous solution in the liquid storage tank 2 flows to the spray head 3 through the pipeline under the action of air pressure, so that the aqueous solution is sprayed out through the spray head 3. Or a pump body is arranged on a pipeline between the spray head 3 and the liquid storage tank 2, and the water solution in the liquid storage tank 2 is pumped to the spray head 3 through the pump body and then is sprayed out through the spray head 3.

As shown in fig. 2, the spraying apparatus further includes a second driving means for moving the spray head 3 in the lengthwise direction of the sample. Specifically, a table on which a sample is placed may be provided inside the airtight can 1, wherein the sample does not simply mean a shape having a significant length and width, and the length direction means a direction in which the spray head 3 moves so that the area covered with the aqueous solution sprayed on the sample is maximized. In addition, aiming at the guide pipe or other structures needing non-single plane spraying, a rotating device can be arranged on the workbench, and the axis of the rotating device is vertically arranged, so that the rotating device rotates along the direction vertical to the horizontal plane to further drive the spray head 3 to rotate for spraying. The rotation speed of the rotating device is set to 100-200rpm, preferably 107rpm or 200rpm, and non-planar spraying is realized.

In some embodiments, the reservoir 2 is vertically oriented, and the level of the aqueous solution within the reservoir 2 is higher than the first filter 21. When in use, the aqueous solution mixed with the inorganic material is guided into the liquid storage tank 2, so that the liquid level of the aqueous solution is higher than that of the first filter screen 21. In the shaking process of the liquid storage tank 2, the aqueous solution drives the inorganic material to pass through the first filter screen 21 in a reciprocating manner, so that the first filter screen 21 serves as a stirring device to ensure that the aqueous solution and the inorganic material are uniformly mixed. Further preferably, the position of the first filter 21 is adapted to the position where the aqueous solution mixed with the inorganic material is separated from the inorganic material after the aqueous solution is precipitated. The adaptive position means that the position of the first filter screen 21 is higher or lower than the position where the aqueous solution and the inorganic material are separated, so that the aqueous solution and the inorganic material can both pass through the first filter screen 21 and be effectively mixed in the shaking process of the liquid storage tank 2. Further optimally, the first filter 21 may be a plurality of horizontally arranged filters, wherein the position of one first filter 21 is adapted to the position of the separation of the aqueous solution and the inorganic material. The plurality of first filters 21 act as a stirring device in cooperation with the first driving device to ensure uniform mixing of the aqueous solution and the inorganic material.

This application guarantees that the storage of protein class aqueous solution and spraying process are all in constant temperature and humidity environment, reduce the conversion rate of protein, filter a small amount of denatured protein through first filter screen 21 simultaneously, avoid appearing the phenomenon that shower nozzle 3 blockked up, rock through liquid storage pot 2, avoid protein class aqueous solution and inorganic material separation, make the mixture more even, ensure the spraying effect, and simultaneously, through shower nozzle 3 with the even spraying of protein class aqueous solution on the sample, increase spraying efficiency, ensure the planarization on coating surface, and can change the thickness of coating according to 3 reciprocating motion's of shower nozzle number, obtain the coating that satisfies the demand. The spraying equipment for the protein aqueous solution can be used for spraying the protein aqueous solution such as silk fibroin, which is greatly influenced by temperature and humidity and is easy to convert in structure.

In some embodiments, as shown in fig. 1, the first drive apparatus of the present application comprises a drive plate 4 and a first drive mechanism. The driving plate 4 is hinged to the liquid storage tank 2, the driving plate 4 is connected with the liquid storage tank 2, the liquid storage tank 2 moves along with the driving plate 4, and the hinged shaft 41 of the driving plate 4 is overlapped with the central line, so that the driving plate 4 can swing along the hinged shaft 41. The first driving mechanism comprises two first electric push rods 42 symmetrically arranged along the hinge shaft 41, one end of each first electric push rod 42 is arranged on the inner wall of the seal tank 1, the other end of each first electric push rod 42 is hinged with the driving plate 4, and in a natural state, the two first electric push rods 42 are perpendicular to the driving plate 4. Wherein, the two first electric push rods 42 have opposite moving directions, that is, when one of the first electric push rods 42 extends, the other first electric push rod 42 retracts to reciprocate, so that the liquid storage tank 2 is shaken along the hinge shaft 41, and the separation of the aqueous solution and the inorganic material is avoided.

Taking the embodiment in fig. 1 as an example, the liquid storage tank 2 is vertically arranged in the sealed tank 1, and the first filter screen 21 is horizontally arranged in the liquid storage tank 2. Wherein, the bottom of liquid storage pot 2 is equipped with the mounting hole, and drive plate 4 rotates to set up in the mounting hole, and two first electric putter 42 set up along vertical direction to the symmetry sets up in the both sides of articulated shaft 41, makes under the natural state, and drive plate 4 is on a parallel with the bottom of liquid storage pot 2, through the flexible of two first electric putter 42, drives liquid storage pot 2 and rocks.

As shown in fig. 2, the second driving apparatus of the present application includes a first slide and a second driving mechanism. The first slide way is arranged along the length direction of the sample, the first base 52 for placing the spray head 3 is arranged on the first slide way, and the second driving mechanism is used for driving the first base 52 to move along the length direction of the first slide way. The moving speed of the first base 52 can be controlled by the second driving mechanism, and then the moving speed of the spray head 3 is controlled, so that the spraying efficiency is increased, and meanwhile, the consistency and uniformity of spraying can be effectively increased by adopting a mechanical control mode.

In some embodiments, the second driving mechanism includes a second electric push rod disposed at the end of the first slide, the second electric push rod extends along the length direction of the first slide, and the end of the second electric push rod is connected to the first base 52. Specifically, the both ends setting of first slide is on the mount pad, and second electric putter's drive division sets up on the mount pad, and the pars contractilis is connected with first base 52, can drive first base 52 through second electric putter's flexible and slide, simple structure, and occupation space is little.

In other embodiments, the first slide includes a first screw 5 and a guide rod 51 arranged along the length direction of the sample, the first base 52 is provided with a through hole in sliding fit with the guide rod 51 and a first screw hole matched with the first screw 5, and the second driving mechanism includes a motor for driving the first screw 5 to rotate. Specifically, both ends of the first lead screw 5 and the guide rod 51 can be arranged on the mounting seats, the both ends of the first lead screw 5 and the mounting seats are rotatably arranged, and the motor is arranged on one of the mounting seats. The first lead screw 5 is driven to rotate by the rotation of the motor, and meanwhile, the degree of freedom of the first base 52 in the circumferential direction of the first lead screw 5 is limited by the guide rod 51, so that the first base 52 moves along the length direction of the first lead screw 5.

The spray head 3 of the present application is hinged on the first base 52 so that the spray head 3 swings in a direction perpendicular to the first slideway for adjusting the angle of the water solution spraying. Specifically, a motor may be disposed on the first base 52, an output shaft of the motor is disposed along a length direction of the first slideway, and the spray head 3 is disposed on the output shaft of the motor, and the spray head 3 is driven to swing by rotation of the motor. Also can set up two risers on first base 52, wear to be equipped with the pivot on two risers, the pivot sets up along the length direction of first slide. One end of the rotating shaft is fixed on one of the vertical plate supports, the other end of the rotating shaft penetrates through the other vertical plate, a thread is arranged at the extending end of the rotating shaft, a nut is arranged on the periphery of the thread, the spray head 3 is rotatably arranged on the rotating shaft, and after the position of the spray head 3 is adjusted, the vertical plate is clamped through the rotating nut, and then the position of the spray head 3 is limited.

Wherein, be equipped with two operation holes on the seal pot 1, and two operation hole position departments are sealed to have gloves, and the equipment in the operator accessible gloves operation seal pot 1. Specifically, when the angle of the nozzle 3 needs to be changed during the spraying process, an operator can enter and exit the glove with two hands to perform operation, so that the sealing performance of the space in the sealed tank 1 is ensured.

As shown in fig. 2, the spraying apparatus further includes a third driving apparatus, the third driving apparatus includes two second slideways 6 arranged in parallel, the two second slideways 6 are provided with second bases 61 in a sliding manner, the second bases 61 at this position are equivalent to the mounting seats, that is, two ends of the first slideway are respectively arranged on the two second bases 61. And a third driving mechanism for driving the second base 61 to slide is arranged on one of the second slide ways 6, so that the first slide way is close to or far away from the sample. The third driving mechanism drives the second base 61 to move along the length direction of the second slide 6, so as to drive the whole first slide to move along the direction, further adjust the distance between the spray head 3 and the sample, and achieve the ideal spraying effect.

In some embodiments, the third driving mechanism includes a third electric push rod disposed at the end of the second slideway 6, the third electric push rod extends and retracts along the length direction of the second slideway 6, and the end of the third electric push rod is connected with the second base 61. Specifically, third electric putter's output shaft sets up on second base 61, and the length direction that can drive second base 61 along second slide 6 through third electric putter's flexible removes, and the mechanism is simple, and positioning accuracy is high.

In other embodiments, one of the second sliding ways 6 is a second screw 62, the second base 61 is provided with a second screw hole matched with the second screw 62, and the third driving mechanism includes a motor for driving the second screw 62 to rotate. The motor drives the second screw rod 62 to rotate, and then drives the second base 61 to move along the length direction of the second screw rod 62, so that the structure is simple, and the occupied space is small.

In other embodiments, both ends of the second slideway 6 are arranged on the bottom plate, a fourth electric push rod is arranged at the bottom of the bottom plate, the position of the spray head 3 in the vertical direction can be changed by stretching of the fourth electric push rod, and the use convenience is improved.

The utility model provides a liquid storage pot 2's inside is equipped with second filter screen 23, and second filter screen 23 sets up between first filter screen 21 and feed inlet, and the aperture of first filter screen 21 is less than the aperture of second filter screen 23. When inorganic materials are added into the aqueous solution, firstly, the inorganic materials are mixed with the aqueous solution and then poured into the liquid storage tank 2, the mixed aqueous solution firstly passes through the second filter screen 23, small blocks which are not fully dispersed are filtered through the second filter screen 23, then a small amount of denatured protein is filtered through the first filter screen 21, and the spray head 3 and the guide pipe of the spray head 3 are placed for blockage.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims

1. The utility model provides a protein class aqueous solution spraying equipment which characterized in that, includes the seal pot, be equipped with humidity control device and a temperature regulation device on the seal pot, be equipped with in the seal pot:

and the spraying equipment comprises a spray head for spraying the aqueous solution in the liquid storage tank towards the direction of the sample, and second driving equipment for driving the spray head to move along the length direction of the sample.

2. The aqueous proteinaceous solution spraying apparatus of claim 1, wherein the first drive apparatus comprises:

the driving plate is hinged to the liquid storage tank and connected with the liquid storage tank, and a hinge shaft of the driving plate is superposed with a central line;

the first driving mechanism comprises two first electric push rods which are symmetrically arranged along the hinge shaft, one end of each first electric push rod is arranged on the inner wall of the sealing tank, the other end of each first electric push rod is hinged to the driving plate, and the two first electric push rods are perpendicular to the driving plate in a natural state.

3. The aqueous proteinaceous solution spraying apparatus of claim 1, wherein the second drive apparatus comprises:

the first slideway is arranged along the length direction of the sample, and a first base for placing the spray head is arranged on the first slideway;

4. The protein aqueous solution spraying device according to claim 3, wherein the first slide way comprises a first screw rod and a guide rod which are arranged along the length direction of the sample, the first base is provided with a through hole in sliding fit with the guide rod and a first screw hole matched with the first screw rod, and the second driving mechanism comprises a motor for driving the first screw rod to rotate.

5. A proteinaceous aqueous solution spraying apparatus according to claim 3, wherein the spray head is hingedly arranged on the first base to oscillate the spray head in a direction perpendicular to the first slide.

6. The protein aqueous solution spraying device according to claim 3, further comprising a third driving device, wherein the third driving device comprises two second slide ways arranged in parallel, a second base is arranged on each of the two second slide ways in a sliding manner, two ends of the first slide way are respectively arranged on the two second bases, and a third driving mechanism for driving the second bases to slide is arranged on one of the second slide ways, so that the first slide way is close to or far away from the sample.

7. The aqueous proteinaceous solution spraying apparatus of claim 6, wherein one of the second slide rails is a second screw rod, the second base is provided with a second screw hole matched with the second screw rod, and the third driving mechanism comprises a motor for driving the second screw rod to rotate.

8. The apparatus according to claim 1, wherein said reservoir is arranged vertically, and the level of the aqueous solution in said reservoir is higher than said first filter.

9. The spraying apparatus for an aqueous protein solution according to claim 8, wherein the first filter is disposed at a position corresponding to a position where the aqueous solution and the inorganic material are separated from each other after the aqueous solution mixed with the inorganic material is precipitated.

10. The apparatus of claim 1, wherein a second filter is disposed inside the liquid storage tank, the second filter is disposed between the first filter and the feed inlet, and the aperture of the first filter is smaller than that of the second filter.