JP2018143927A - Rotary atomizer and spray dryer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary atomizer which can effectively cool bearings without using a lubricant.SOLUTION: A rotary atomizer 1 sprays an undiluted solution by a disc 18 which rotates at high speed and includes: a base plate 13; a motor 11 attached onto the base plate 13; a shaft 16 which penetrates through the base plate 13 and in which an upper end is coupled to the motor 11 and the disc 18 is attached to a lower end; a shaft cover 17 covering the shaft 16; bearings 20, 30 which receive the shaft 16; a jacket skirt 15 which includes a substantially tapered wall part provided at the base plate 13 and forms a space including the shaft cover 17 in an area from the base plate 13 to the disc 18; a pipeline 14 in which outlets 14a, 14b are disposed near the bearings 20, 30; and a blower 40 which sends air for cooling the upper and lower bearings 20, 30 to the pipeline 14.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a rotary atomizer capable of cooling a bearing without using lubricating oil, and a spray dryer provided with the same.

  A spray dryer is a drying facility that instantly generates particles by spraying a stock solution into a drying chamber and continuously contacting the solution with hot air. As a spraying method, a nozzle method or a rotary atomizer method is generally adopted. Hereinafter, the configuration of a conventional spray dryer will be described as an example. FIG. 4 is a schematic diagram showing a spray dryer facility according to the applicant's existing technology.

  A spray dryer facility 100 shown in FIG. 4 includes a drying chamber 101 and a cyclone 102. This spray dryer equipment 100 employs a two-point collection method, and generated particles are collected at two points, a lower part of the drying chamber 101 and a lower part of the cyclone 102. In the drying chamber 101, particles having excellent fluidity are generated. The particles fall inside the drying chamber 101 and are collected in the lower part thereof. On the other hand, relatively light particles and fine particles are sucked out of the drying chamber 101 by the blower and collected by the cyclone 102.

  Next, the configuration of the drying chamber 101 will be described with reference to FIGS. 5 (a) and 5 (b). In FIG. 5A, the drying chamber 101 has a wall portion having a cylindrical shape in the upper portion and an inverted conical shape in the lower portion. An air disperser 110 is installed on the ceiling of the drying chamber 101. A rotary atomizer 120 is attached to the center of the air disperser 110. On the other hand, on the wall surface of the drying chamber 101, a pipe-shaped air bloom 130 that is bent along the shape of the wall surface is disposed oppositely.

  As shown in FIG. 5B, the air disperser 110 includes a housing 111 and a lower part 112. The housing 111 has a donut-shaped outer shape whose center is opened in a circular shape. An annular air passage is formed inside the housing 111. This air passage surrounds the opening at the center of the housing 111. The hot air supplied to the air passage inside the housing 111 swirls along the shape of the air passage and is discharged toward the outer peripheral surface of the lower part 112.

  The lower part 112 mainly includes an inverted conical wall portion. The lower part 112 is suspended in the opening at the center of the housing 111. The tapered outer peripheral surface of the lower part 112 is exposed to the hot air swirling flow from the housing 111.

  A rotary atomizer 120 is suspended from the lower end opening of the lower part 112. The rotary atomizer 120 includes a disk (disk) that rotates at high speed by a motor. When the stock solution is supplied to the disk that rotates at high speed, the stock solution is accelerated on the disk surface and scattered at high speed from the periphery of the disk. As a result, the stock solution is sprayed into the drying chamber 101 in the form of a mist. The stock solution sprayed into the drying chamber 101 comes into contact with the hot air swirl flow supplied from the air disperser 110 into the drying chamber 101 and is instantaneously dried and granulated.

JP-A-8-052387 Japanese Patent Laid-Open No. 7-328489 JP 2008-207096 A

<Deterioration of bearing>
Generally, hot air exceeding 200 ° C. is supplied into the drying chamber of the spray dryer, and the temperature becomes extremely high. Depending on the type of particles to be produced, the drying chamber may exceed 600 ° C. The rotary atomizer rotates the disk at a high speed (for example, 10,000 to 20,000 rpm) while being exposed to such a high temperature in the drying chamber. For this reason, the conventional rotary atomizer has a problem in that the bearing that receives the shaft is severely deteriorated and its life is short. For this reason, the deteriorated bearing had to be replaced frequently.

<Hygiene issues>
In order to prevent deterioration of the bearing due to high temperature, for example, Patent Documents 1 and 2 disclose a rotary atomizer configured to circulate lubricating oil and cool the bearing. Patent Document 3 discloses a rotary atomizer configured to cover a rotary atomizer with a double protective case and to circulate cooling water in the double protective case. However, the rotary atomizer is placed in a drying chamber where the particles are produced. In the unlikely event that the lubricating oil or cooling water circulating inside the rotary atomizer leaks, foreign matter will be mixed into the manufactured particles. Foreign matter contamination not only degrades the quality of the product particles, but also an accident that must not be sanitary if the particles are food, pharmaceuticals and cosmetics.

<Deterioration of bearing housing>
The conventional rotary atomizer has a problem that the bearing housing deteriorates together with the bearing. The bearing housing is a part for fixing the bearing to the shaft. The bearing housing has a size that accommodates the entire bearing, and is made of, for example, stainless steel or nickel chrome steel having excellent corrosion resistance and wear resistance. The bearing becomes high temperature exceeding 100 ° C. as it deteriorates, and transmits the vibration of the shaft to the bearing housing. For this reason, the part which contacts a bearing among bearing housings deteriorates. Conventionally, the entire bearin housing in which the portion in contact with the bearing has deteriorated is discarded and replaced with a new bearing housing. Discarding the entire bearing housing with only a partial deterioration is contrary to modern social demands for effective use of resources.

<Object of invention>
The present invention has the following objects.
・ Provide a rotary atomizer that can cool the bearing effectively and prevent deterioration of the bearing without the possibility of contamination of the product particles. ・ Deteriorated part of the bearing housing To provide a rotary atomizer that can be replaced only.-To provide a spray dryer equipped with the above rotary atomizer.

(1) In order to achieve the above object, a rotary atomizer of the present invention is a rotary atomizer in which a stock solution is sprayed by a disk that rotates at high speed, and includes a base plate, a motor mounted on the base plate, and the base plate. A shaft having a top end coupled to the motor and having the disk attached to the bottom end, a shaft cover covering the shaft, at least one bearing for receiving the shaft, and a substantially tapered shape provided on the base plate. A jacket skirt that includes a wall portion and forms a space including the shaft cover between the base plate and the disk; a pipe line having an outlet disposed in the vicinity of the bearing; and for cooling the bearing Blower that sends air into the pipe , A configuration equipped with.

(2) Preferably, in the rotary atomizer of (1) above, the bearing is provided below the center of the shaft and is located in the space of the jacket skirt, and the outlet of the conduit is the base plate It is good to set it as the structure distribute | arranged in the space of the said jacket skirt via.

(3) Preferably, in the rotary atomizer of the above (1), a cooling chamber capable of ventilation is provided between the base plate and the motor, and the bearing is provided above the center of the shaft, and It is good to set it as the structure located in the said cooling chamber, and the exit of the said pipe line connected to the said cooling chamber.

(4) Preferably, in the rotary atomizer of (1) above, a cooling chamber capable of ventilation is provided between the base plate and the motor, and the bearing is provided below the center of the shaft, and A lower bearing located in the space of the jacket skirt, and an upper bearing provided above the center of the shaft and located in the cooling chamber, wherein the pipe line has at least two outlets, One outlet may be arranged in the space of the jacket skirt through the base plate, and the other outlet may be communicated with the cooling chamber.

(5) Preferably, in the rotary atomizer according to any one of (1) to (4), the jacket skirt includes a substantially tapered double wall portion, and a heat insulating material is provided between the double wall portions. It is good to make the structure filled with.

(6) Preferably, in the rotary atomizer of the above (5), a vacuum pump for sucking air from between the double wall portions of the jacket skirt may be provided.

(7) Preferably, in the rotary atomizer according to any one of the above (1) to (6), a bearing housing for fixing the bearing to the shaft is provided, and the bearing housing includes an inner part that contacts the bearing; The inner part may be configured to include an outer part that is exchangeably coupled.

(8) In order to achieve the above object, a spray dryer according to the present invention includes the rotary atomizer according to any one of the above (1) to (7).

  According to the rotary atomizer of the present invention, it is possible to effectively cool the bearing without using a lubricant, and it is possible to prevent deterioration of the bearing without the possibility of foreign matter entering the product particles. Therefore, the rotary atomizer of the present invention has high hygiene reliability and the effect that the life of the bearing can be extended. Extending the life of the bearing leads to a reduction in the number of maintenance of the rotary atomizer. As a result, the spray dryer provided with the rotary atomizer of the present invention improves the particle production efficiency.

  Further, according to the rotary atomizer of the present invention, it is possible to replace only the deteriorated inner part in the bearing housing, and it is possible to use the outer part permanently.

FIG. 1 is an external view of a rotary atomizer according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the rotary atomizer. FIG. 3 shows a bearing housing provided in the rotary atomizer. FIG. 3 (a) is a plan view and FIG. 3 (b) is a cross-sectional view. FIG. 4 is a schematic diagram of a spray dryer facility according to the applicant's existing technology. FIG. 5 shows a drying chamber constituting the spray dryer equipment. FIG. 5 (a) is a schematic diagram of the entire drying chamber, and FIG. 5 (b) is a schematic diagram of an air disperser provided in the drying chamber. It is.

  Hereinafter, a rotary atomizer according to an embodiment of the present invention will be described with reference to FIGS.

<External structure>
As shown in FIG. 1, the rotary atomizer 1 of the present embodiment has a configuration in which a disk 19 is rotated at a high speed by a motor 11 and a stock solution is sprayed into a drying chamber (not shown). The motor 11 is fixed on the base plate 13 via the motor base 12. On the base plate 13, a cooling air outlet 13a and a pipe line 14 are provided. On the other hand, a jacket skirt 15 is fixed under the base plate 13. The jacket skirt 15 constitutes a substantially tapered wall portion whose diameter decreases from top to bottom. A disk 19 is rotatably attached to the lower end of the jacket skirt 15.

<Internal structure>
As shown in FIG. 2, the inside of the motor base 12 is a hollow cooling chamber 12a. The inside of the cooling chamber 12a can be ventilated through a punching mesh cover 12b (see FIG. 1) attached to the wall. In the cooling chamber 12 a, the rotating shaft of the motor 11 is coupled to the upper end of the shaft 16.

  The shaft 16 passes through the base plate 13, passes through the jacket skirt 15, and extends downward. The shaft 16 is covered with a shaft cover 17 in the jacket skirt 15. The lower end of the shaft 16 protruding from the shaft cover 17 passes through the liquid distributor 18 and is coupled to the disk 19. The liquid distributor 18 is fixed to the lower end of the shaft cover 17. The rotation of the motor 11 is transmitted to the shaft 16, and the disk 19 is rotated at a high speed below the liquid distributor 18.

  A stock solution pipe (not shown) is inserted into the base plate 13. The stock solution pipe passes through the jacket skirt 15 and is connected to the liquid distributor 18. A stock solution that is processed into particles by a spray dryer (not shown) flows through the stock solution pipe to the liquid distributor 18. The liquid distributor 18 supplies the stock solution to the center of the disk 19 that rotates at high speed.

  The shaft 16 is rotatably supported by the upper bearing 20 and the lower bearing 30. The upper bearing 20 is provided above the center of the shaft 16 and is located in the cooling chamber 12a. The upper bearing 20 is accommodated in the upper bearing housing 21. The upper bearing housing 21 is coupled to the upper end of the shaft cover 17. On the other hand, the lower bearing 30 is provided below the center of the shaft 16 and is located in the jacket skirt 15. The lower bearing 30 is accommodated in the lower bearing housing 31. The lower bearing housing 31 is fixed in the shaft cover 17.

<Bearing cooling structure>
Here, the rotary atomizer 1 of the present embodiment has a structure that cools the upper bearing 20 and the lower bearing 30 without using any lubricating oil (OIL-FREE). The bearing cooling structure of the present embodiment is mainly constituted by the cooling chamber 12 a of the motor base 12, the conduit 14, the jacket skirt 15, the blower 40 and the vacuum pump 50.

<< Forced air cooling >>
The pipe line 14 has a bifurcated structure having a first outlet 14a and a second outlet 14b. The first outlet 14a is connected to the motor base 12 and communicates with the cooling chamber 12a. The first outlet 14a is directed to the upper bearing 20 located in the cooling chamber 12a. On the other hand, the second outlet 14 b is disposed in the space formed by the jacket skirt 15 via the base plate 13. The second outlet 14 b is directed to the lower bearing 30 in the shaft cover 17.

  A blower 40 is connected to the inlet of the conduit 14. The blower 40 sends air into the pipe line 14. The air sent into the pipe line 14 is discharged from the first outlet 14a and the second outlet 14b through the pipe line 14 and forcibly cools the upper bearing 20 and the lower bearing 30.

<< Vacuum insulation >>
The lower bearing 30 located in the space of the jacket skirt 15 is exposed to a high temperature in a drying chamber of a spray dryer (not shown). For this reason, it is necessary to suppress the heat transfer from the drying chamber into the space of the jacket skirt 15 and keep the temperature around the lower bearing 30 low. Therefore, in this embodiment, the jacket skirt 15 is provided with a function of vacuum insulation.

  The jacket skirt 15 is composed of a first wall portion 15a and a second wall portion 15b that are substantially tapered. These 1st and 2nd wall parts 15a and 15b are formed with SUS316 which is stainless steel material with high corrosion resistance, for example. A gap is formed between the first wall portion 15a and the second wall portion 15b, and this gap is filled with a heat insulating material 15c. The material of the heat insulating material 15c is not particularly limited. As long as it is excellent in heat resistance, for example, the heat insulating material 15c made of any material of fiber type or foam type may be used.

  A gap between the first wall portion 15a and the second wall portion 15b is connected to the vacuum pump 50 through a pipe. One end of the pipe communicates with the gap between the first wall portion 15a and the second wall portion 15b via the second wall portion 15b. The other end of the pipe is connected to the vacuum pump 50 through the base plate 13 from the space of the jacket skirt 15. The vacuum pump 50 sucks air from the gap between the first wall portion 15a and the second wall portion 15b, and places the gap in a vacuum state.

<< Operational effects of bearing cooling structure >>
The upper bearing 20 is forcibly air-cooled by the air sent from the blower 40 in the cooling chamber 12 a of the motor base 12. Thereby, during operation of the rotary atomizer 1, the temperature of the upper bearing 20 is maintained within the range of 50 to 90 ° C. Moreover, the air sent from the air blower 40 is discharged | emitted outside from the cooling chamber 12a through the punching mesh cover 12b.

  On the other hand, the lower bearing 30 is forcibly air-cooled by the air sent from the blower 40 in the space thermally insulated by the jacket skirt 15. That is, heat conduction from the drying chamber of a spray dryer (not shown) is suppressed by the heat insulating material 15c filled in the gap between the first wall portion 15a and the second wall portion 15b. Further, the gap between the first wall portion 15a and the second wall portion 15b is brought into a vacuum state by the vacuum pump 50, so that heat conduction and convection due to the presence of air hardly occur. In such a vacuum-insulated environment, the lower bearing 30 is forcibly cooled by the air sent from the blower 40. As a result, during operation of the rotary atomizer 1, the temperature of the lower bearing 30 is maintained within a range of 50 to 90 ° C. Further, the air sent from the blower 40 is discharged to the outside of the jacket skirt 15 through the cooling air outlet 13a.

  According to the above-described bearing cooling structure of the present embodiment, the upper and lower bearings 20 and 30 can be effectively cooled without using a lubricant. It is possible to prevent deterioration of the lower bearings 20 and 30. Therefore, the rotary atomizer 1 of the present embodiment has high hygiene reliability, and has an effect that the life of the upper and lower bearings 20 and 30 can be extended. Extending the service life of the upper and lower bearings 20 and 30 leads to a reduction in the number of maintenances of the rotary atomizer 1. As a result, the spray dryer provided with the rotary atomizer 1 of the present embodiment improves the particle production efficiency.

<Bearing housing>
Next, the structure of the upper bearing housing 21 of this embodiment is demonstrated, referring FIG.2 and FIG.3. The lower bearing housing 31 has the same configuration as the upper bearing housing 21 described below, but detailed description thereof is omitted.

  As shown in FIG. 2, when the upper bearing 20 deteriorates due to its life, the shaft 16 starts to vibrate, and this vibration is transmitted to the upper bearing housing 21. For this reason, the part which contacts the upper bearing 20 among the upper bearing housing 21 also deteriorates. The upper bearing housing 21 is a large component that accommodates the entire upper bearing 20 and is made of a metal material having excellent corrosion resistance and wear resistance. Therefore, discarding the entire upper bearing housing 21 with only a partial deterioration is contrary to modern social demands for effective use of resources.

  Therefore, in this embodiment, as shown in FIGS. 3A and 3B, the upper bearing housing 21 is composed of two parts, an outer part 21a and an inner part 21b. As shown in FIG.3 (b), the internal thread of the upper part of the outer part 21a is provided with the internal thread. On the outer peripheral surface of the inner part 21b, a male screw that is screwed into the female screw of the outer part 21a is provided. As shown in FIG. 3A, the upper surface of the inner part 21b is provided with two holes into which a tool (not shown) is inserted, and the inner part 21b can be replaced using the tool. The inner diameter of the inner part 21b is substantially equal to the outer diameter of the upper bearing 20 shown in FIG. 2, and the upper bearing 20 is accommodated in the inner part 21b screwed to the outer part 21a. The outer peripheral surface of the upper bearing 20 contacts only the inner peripheral surface of the inner part 21b.

  Such outer part 21a and inner part 21b are formed of the same metal material. For example, the outer part 21a and the inner part 21b may be formed of stainless steel or nickel chrome steel excellent in corrosion resistance and wear resistance.

<Function and effect of bearing housing>
According to the upper bearing housing 21 of the present embodiment, since the outer peripheral surface of the upper bearing 20 contacts only the inner peripheral surface of the inner part 21b, only the inner part 21b deteriorates even when subjected to vibration of the shaft 16, The outer part 21a does not deteriorate. Therefore, the outer part 21a can be used permanently by exchanging only the deteriorated inner part 21b.

DESCRIPTION OF SYMBOLS 1 Rotator atomizer 11 Motor 12 Motor base 12a Cooling chamber 12b Punching mesh cover 13 Base plate 13a Cooling air outlet 14 Pipe line 14a First outlet 14b Second outlet 15 Jacket skirt 15a First wall 15b Second wall 15c Thermal insulation 16 Shaft 17 Shaft cover 18 Liquid distributor 19 Disc 20 Upper bearing 21 Upper bearing housing 30 Lower bearing 31 Lower bearing housing 40 Blower 50 Vacuum pump

Claims (8)

A rotary atomizer that sprays stock solution with a high-speed rotating disk,
A base plate;
A motor mounted on the base plate;
A shaft penetrating the base plate, having an upper end coupled to the motor and having the disk attached to the lower end;
A shaft cover covering the shaft;
At least one bearing for receiving the shaft;
A jacket skirt having a substantially tapered wall portion provided on the base plate, and forming a space including the shaft cover between the base plate and the disk;
A conduit having an outlet disposed in the vicinity of the bearing;
A blower for sending air to cool the bearing into the pipe;
A rotary atomizer characterized by comprising: The bearing is provided below the center of the shaft and located in the space of the jacket skirt;
The rotary atomizer according to claim 1, wherein an outlet of the pipe line is disposed in the space of the jacket skirt through the base plate. A ventilated cooling chamber is provided between the base plate and the motor,
The bearing is provided above the center of the shaft and is located in the cooling chamber;
The rotary atomizer according to claim 1, wherein an outlet of the conduit communicates with the cooling chamber. A ventilated cooling chamber is provided between the base plate and the motor,
A lower bearing located below the center of the shaft and located in the space of the jacket skirt; an upper bearing located above the center of the shaft and located in the cooling chamber; Including,
The pipe line has at least two outlets, one outlet is disposed in the space of the jacket skirt through the base plate, and the other outlet is in communication with the cooling chamber. The described rotary atomizer.   The rotary atomizer according to any one of claims 1 to 4, wherein the jacket skirt includes a substantially tapered double wall portion, and a heat insulating material is filled between the double wall portions.   The rotary atomizer according to claim 5, further comprising a vacuum pump for sucking air from between the double walls of the jacket skirt.   The bearing housing for fixing the said bearing to the said shaft, The said bearing housing contains the inner part which contacts the said bearing, and the outer part to which the said inner part is couple | bonded so that replacement | exchange is possible. The rotary atomizer according to any one of the above.   The spray dryer provided with the rotary atomizer of any one of Claims 1-7.