JP2012013265A - Circulation type spray drying equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively prevent the external leakage of circulating gas and a solvent contained in a raw material solution.SOLUTION: Spray drying equipment includes: a spray drying tower which dries a mist of the raw material solution sprayed from a nozzle and turns it into particulates; a powder recovery unit which separates the particulates dried by the spray drying tower from the circulating gas so as to recover them; a condenser which separates the solvent of the raw material solution by cooling the circulating gas; and a gas compressor for pressurizing the circulating gas from which the solvent is separated so as to supply it to the nozzle of the spray drying tower. The gas compressor comprises a piston shaft 43 which performs a linear motion in the reciprocation direction of a piston 41 by a piston-type forced transfer machine 4A reciprocating the piston 41 in a cylinder 40, and a reciprocation mechanism 34 which reciprocates the piston shaft 43. An opening on the side of the reciprocation mechanism 34 of the cylinder 40 is closed by a closing plate 47, and the closing plate 47 airtightly closes a surface of the slidably-penetrating piston shaft 43 by a seal 48.

Description

  The present invention relates to a spray drying apparatus that sprays a raw material solution into a spray drying tower in the form of a mist and dries the sprayed mist to form fine particles, and in particular, a circulating gas for atomizing the raw material solution in a closed loop. The present invention relates to a circulating spray drying apparatus.

  A circulation type spray drying apparatus using an inert gas, in which powder is obtained by spraying and drying a liquid raw material using an organic solvent as a solvent, has been put into practical use. (See Patent Document 1)

  In a conventional circulation type spray drying apparatus, a liquid raw material sprayed by a sprayer is instantaneously dried and powdered by a spray drying tower equipped with a sprayer by a circulating gas such as an inert gas heated by a heater. Collect with a powder collector such as The circulating gas that has passed through the powder recovery device is passed through the condenser to condense and recover the solvent contained in the gas, and is sent to a heater by a circulation device for circulation.

  A conventional circulation spray drying apparatus is shown in FIG. This spray drying apparatus uses nitrogen gas as a circulating gas. Nitrogen gas is heated by the heater 107 and supplied to the spray drying tower 101. The heated nitrogen gas dries the mist sprayed from the nozzle 105 into the spray drying tower 101 to form fine particles. The nitrogen gas discharged from the spray drying tower 101 is supplied to the cyclone 102 to separate the fine particles. The circulating gas from which the fine particles have been separated is cooled by the condenser 103 to separate the solvent contained in the circulating gas. For example, when the solvent of the raw material solution sprayed from the nozzle is alcohol, alcohol vaporized into nitrogen gas in a state where the mist is dried and fine particles are separated is included. The condenser 103 cools the circulating gas and separates alcohol as a solvent contained in the raw material solution. The circulating gas from which the solvent has been separated is circulated to the spray drying tower 101 by the blower 106. The spray drying apparatus shown in the figure has a blower 106 connected as a circulator between two-stage condensers 103.

  The spray drying apparatus shown in FIG. 1 uses a nozzle of a type that does not use compressed gas from the outside. Such nozzles generally use a rotating plate system utilizing centrifugal force, but it is difficult to obtain a micron order or submicron order powder by this system.

In addition, devices have been developed that include nozzles that spray pressurized gas and liquid together. (See Patent Document 2)
The nozzle described in Patent Document 2 is shown in FIG. The nozzle 205 can spray the liquid by crushing it into fine particles with a pressurized gas flow. This nozzle 205 needs to supply not only the raw material solution but also pressurized gas. The circulation type spray drying apparatus can use the circulation gas circulating in the spray drying tower 201 as the gas supplied to the nozzle 205. However, since the circulating gas supplied to the nozzle 205 can increase the pressure of the supplied gas and reduce the average particle diameter of the mist to be sprayed, it is necessary to pressurize the circulating gas with a gas compressor 204 such as a compressor.

  However, when the sprayer is a nozzle type that uses compressed gas, the compressed gas is supplied from the outside and discharged after passing through the condenser by the amount supplied to the nozzle, and the gas after passing through the condenser is compressed by the compressor. There is a form of suction and supply to the nozzle. The former requires a large amount of inert gas, which increases the running cost. Also, since the solvent cannot be completely recovered even by the condenser, the gas in which the solvent remains is discharged to the outside. It is impossible to obtain a recovery rate. In the latter case, unlike the former, the amount of residual gas discharged to the outside is suppressed, but a compressor that reciprocates a commonly used piston has a sealing structure only in the piston, so that it is completely airtight. It is difficult to produce, and the gas in which the solvent remains is discharged to the outside during the discharge process that pressurizes and extrudes the gas, and it is necessary to supply an inert gas to maintain the internal pressure in the device. It is difficult to get a rate. In addition, like a compressor for compressing refrigerant used in a general cooling device, it may be possible to casing related members such as a motor as a single unit to ensure airtightness. It is difficult to suppress completely with the seal of the piston portion, and oil is mixed in the compressed gas. Therefore, it cannot be used as the gas to be supplied depending on the type of raw material and the field of application of the powder.

  Further, the same can be said for a blower used for a circulator that forcibly blows circulating gas. In general, a propeller type or roots type blower is often used as the circulation machine. However, in both cases, it is difficult to seal the rotating shaft and the bearing that rotate at high speed in a completely airtight state, and it is difficult to achieve complete airtightness.

  In order to condense the solvent from the gas, the higher the gas pressure, the higher the condensation efficiency, that is, the recovery efficiency. Therefore, it is desirable to arrange a circulator upstream of the condenser and blow the circulated gas to the condenser in a pressurized state. However, if the circulator is low in airtightness, the concentration of the solvent before condensation is high. As a result, the circulator is often installed on the downstream side of the condenser, and the ratio of the solvent remaining in the circulating gas is high.

JP 2002-143669 A JP-A-4-11901

  The blower of the apparatus of FIG. 1 and the gas compressor of the apparatus shown in FIG. 2 are difficult to eliminate gas leakage from the sliding part, and there is a problem that circulating gas leaks to the outside. The blower cannot completely seal the bearing, and the compressor, which is a piston-type gas compressor, cannot completely eliminate the leakage of circulating gas from between the piston and the cylinder. Therefore, for example, in a compressor having a discharge pressure of 0.6 MPa at a flow rate of 100 liters / minute, as much as 50 liters of gas leaks per hour. The piston has a piston ring on its outer periphery to improve airtightness, but it is impossible to eliminate a slight gas leak generated between the piston ring and the cylinder. Furthermore, since the piston ring expands along the inner surface of the cylinder and closes the gap with the cylinder, the both end faces cannot always adhere closely to each other, and gas leakage from this gap cannot be eliminated at all. An apparatus in which circulating gas leaks from the compressor needs to be supplemented with circulating gas in order to keep the internal pressure in the apparatus constant. In addition, since the condenser cannot completely recover the solvent, the solvent also leaks to the outside together with the circulating gas.

  As described above, the gas leakage of the compressor can be eliminated by a structure in which related members such as a motor are integrated in an airtight casing like a compressor for refrigerant compression used in a general cooling device. However, this structure cannot be used for a compressor that pressurizes the circulating gas because the oil in the compressor flows into the circulating gas.

  In order to prevent mixing of the lubricating oil, the compressor cannot store both the motor and the cylinder in an airtight case. For this reason, the gas compressor used in the circulation type spray drying apparatus cannot completely eliminate the circulation gas to be circulated and the solvent contained in the raw material solution to the outside, and a slight leakage occurs. For this reason, it is necessary to supply the circulating gas during operation, and there is a problem that the environment where the solvent such as alcohol leaks to the outside is deteriorated.

  The present invention has been developed for the purpose of solving this drawback. An important object of the present invention is to provide a circulation type spray drying apparatus capable of effectively preventing external leakage of a solvent contained in a circulation gas or a raw material solution.

Means for Solving the Problems and Effects of the Invention

In summary, the spray drying apparatus of the present invention includes a spray drying tower incorporating a sprayer from the upstream side, a powder recovery unit for recovering the dried powder, a condenser for recovering the solvent, and a gas compressor to be further equipped, and The circulator uses a reciprocating motion mechanism that converts the rotational motion of a crank mechanism or the like into the reciprocating motion of the piston, but also adds a unique mechanism that converts the reciprocating motion into a linear reciprocating motion, It is characterized by a linear reciprocating drive or a diaphragm system.
The spray drying apparatus of the present invention has a unique structure in which the gas compressor and the circulator to be used convert the reciprocating motion to the linear reciprocating motion while converting the reciprocating motion to the reciprocating motion of the piston. It is characterized by driving.
As described above, in the conventional reciprocating type gas compressor, the sealing of the compressed gas can be performed only by the piston. However, the gas compressor and circulator used in the spray drying apparatus of the present invention converts the rotary motion obtained by a rotating machine such as a motor into a reciprocating motion using a mechanism such as a crank, and further converts the reciprocating motion into a linear reciprocating motion. The piston shaft is sealed in motion, and the piston shaft can be sealed, which was impossible with the conventional reciprocating system.

The above-mentioned circulation type spray drying device is markedly different from a conventional piston-type forced transfer machine that seals only between the piston and the cylinder because the piston shaft can be sealed. It is possible to obtain a gas compressor and a circulator having high airtightness.
Moreover, the spray drying apparatus of this invention is realizable also with the gas compressor and circulator to be used with a diaphragm system.

Similarly, it is possible to obtain a gas compressor and a circulator having high hermeticity by the diaphragm method. A circulation type spray drying apparatus equipped with such a gas compressor and a circulator is in a completely sealed state, and product powder can be obtained by spray drying without releasing circulating gas and solvent to the outside. And a spray drying device with low operating costs.
The above spray drying apparatus is a piston-type forced transfer machine that reciprocates the piston in the cylinder and pressurizes and feeds the circulating gas while preventing external leakage of the solvent contained in the circulating gas and the raw material solution. Since the pressure of the circulating gas supplied to the nozzle from the gas compressor can be increased, the fine particles produced by reducing the average particle diameter of the mist sprayed to the spray drying tower can be made smaller if necessary. There is also. Furthermore, the piston-type forced transfer machine seals the sliding portion between the surface of the piston shaft and the through-hole of the closing plate to form an airtight structure. It is possible to improve the airtightness by narrowing the sealing area. As described above, the circulation type spray drying apparatus of the present invention minimizes the leakage of the circulating gas circulated by the gas compressor and the solvent contained in the raw material solution to the outside, so that the supply of the circulating gas is minimized. However, it is possible to effectively prevent the solvent such as alcohol from leaking to the outside and deteriorating the installation environment.

  In particular, the spray drying device of the present invention can also be provided with an oil seal on the piston shaft. By adopting this structure, oil and grease used for the rotating shaft and the like are prevented from flowing into the circulating gas. Is possible. This exerts a tremendous effect particularly when producing powders for medical use in which contamination from foreign substances is strictly prohibited.

  As described above, in order to condense the solvent from the gas, the higher the gas pressure, the higher the condensation efficiency, that is, the recovery efficiency. Therefore, it is desirable to place a circulator upstream of the condenser and blow the circulated gas to the condenser in a pressurized state. However, if the circulator is low in airtightness, a gas containing a high concentration of solvent before condensation is In general, the circulator is often installed on the downstream side of the condenser because the solvent recovery rate is significantly impaired. However, since the circulator used in the circulation type spray drying apparatus of the present invention is highly airtight and has almost no outflow of gas, it is possible to arrange the circulator upstream of the condenser. As a result, it is possible to achieve condensation with a high gas pressure, that is, condensation with a high recovery rate.

  As a matter of course, in the circulation type spray drying apparatus, both the gas compressor and the circulator include a gas compressor and a circulator of a piston-type forced transfer machine, or a gas compressor composed of a diaphragm-type forced transfer machine and It is ideal to use either of the circulators, but the gas of the piston-type forced transfer machine and the circulator, or the gas of the diaphragm-type gas compressor is used for either the gas compressor or the circulator. Since the outflow can be reduced outside by using a compressor and a circulator, a great effect can be expected. Therefore, in the circulation type spray drying apparatus, the present invention is effective even when a piston type forced transfer machine or a diaphragm type forced transfer machine is provided in either one of the gas compressor and the circulation machine.

  In addition, even in a circulation type spray drying apparatus equipped with a rotating plate type nozzle using a centrifugal force, the nozzle used in the circulation type spray dryer does not use compressed gas. Since there is a requirement that the gas flow out as little as possible, it is a matter of course that the present invention which proposes a circulation type spray drying apparatus equipped with a highly airtight circulator is very effective.

The first circulation type spray drying apparatus of the present invention comprises a spray drying tower 1 for drying a mist of a raw material solution sprayed from a nozzle 5 through a pressurized circulation gas into fine particles, and the spray drying tower. The powder recovery device 2 that separates and collects the fine particles dried in 1 from the circulating gas, and the condensation that cools the circulating gas from which the fine particles have been separated by the powder recovery device 2 to liquefy and separate the solvent of the raw material solution And a gas compressor 4 that pressurizes the circulating gas from which the solvent has been separated by the condenser 3 and supplies the pressurized gas to the nozzle 5 of the spray drying tower 1.
The gas compressor 4 is a piston-type forced transfer machine 4A that reciprocates the piston 41 in the cylinder 40 to pressurize and circulate the circulating gas, and this piston-type forced transfer machine 4A is the reciprocating direction of the piston 41. And a piston shaft 43 that linearly moves in the reciprocating direction of the piston 41, and reciprocating mechanisms 34 and 24 that reciprocate the piston shaft 43. Further, the openings on the reciprocating mechanism 34, 24 side of the cylinder 40 are closed by a closing plate 47 having a through hole 47A through which the piston shaft 43 slidably passes. The closing plate 47 includes a seal 48 that seals the surface of the piston shaft 43 that is slidably passed through the through hole 47A in an airtight structure. The circulation type spray drying apparatus pressurizes the circulation gas by the piston type forced transfer machine 4A and supplies it to the nozzle 5, and atomizes the raw material solution into fine mist from the nozzle 5.

  The second circulation type spray drying apparatus of the present invention comprises a spray drying tower 1 for drying a mist of a raw material solution sprayed from a nozzle 5 through a pressurized circulation gas into fine particles, and the spray drying tower. The powder recovery device 2 that separates and collects the fine particles dried in 1 from the circulating gas, and the condensation that cools the circulating gas from which the fine particles have been separated by the powder recovery device 2 to liquefy and separate the solvent of the raw material solution And a gas compressor 4 that pressurizes the circulating gas from which the solvent has been separated by the condenser 3 and supplies the pressurized gas to the nozzle 5 of the spray drying tower 1. The gas compressor 4 is a diaphragm type forced transfer machine 4B. This spray drying apparatus pressurizes the circulating gas with this diaphragm-type forced transfer device 4B and supplies it to the nozzle 5, and atomizes the raw material solution into fine mist from the nozzle 5.

  In the above circulation type spray drying apparatus, since the gas compressor is a diaphragm type forced transfer machine, external leakage of the solvent contained in the circulation gas and the raw material solution in the gas compressor can be surely prevented. For this reason, this spray drying apparatus pressurizes the circulating gas to a high pressure with a gas compressor and supplies it to the nozzle, reducing the average particle diameter of the mist sprayed on the spray drying tower, and producing smaller fine particles, External leakage of the solvent contained in the circulating gas and the raw material solution can be prevented.

  The third circulation type spray drying apparatus of the present invention is the circulation type spray drying apparatus according to the first or second aspect, and includes a circulation path 8 for circulating the circulation gas to the spray drying tower 1. . The circulation path 8 includes a main circulation path 8A that circulates the gas discharged from the spray drying tower 1, and a first branch path 8B and a second branch path 8C that are connected to the discharge side of the main circulation path 8A. The first branch path 8B is connected to the gas compressor 4 and the tip thereof is connected to the nozzle 5, and the second branch path 8C is connected to the spray drying tower 1 without passing through the nozzle 5. Yes. Further, the main circulation path 8A or the second branch path 8C is connected to a circulation machine 6 for circulating the circulation gas. The circulator 6 is a piston-type forced transfer machine 6A that circulates circulating gas by reciprocating the piston 41 in the cylinder 40. This piston-type forced transfer machine 6A includes a piston shaft 43 that extends in the reciprocating direction of the piston 41 and linearly moves in the reciprocating direction of the piston 41, and reciprocating mechanisms 34 and 24 that reciprocate the piston shaft 43. I have. Further, the openings on the reciprocating mechanism 34, 24 side of the cylinder 40 are closed by a closing plate 47 having a through hole 47A through which the piston shaft 43 slidably passes. The closing plate 47 includes a seal 48 that seals the surface of the piston shaft 43 that is slidably passed through the through hole 47A in an airtight structure. The spray drying apparatus circulates the circulating gas to the spray drying tower 1 with the circulator 6 of the piston type forced transfer device 6A.

  The above-mentioned circulation type spray drying apparatus includes a circulation path for circulating the circulation gas to the spray drying tower, and a circulation machine for circulating the circulation gas is connected to the circulation path so that the circulation machine has a unique structure. Thus, there is a feature that the external leakage of the solvent contained in the circulating gas or the raw material solution can be effectively prevented. This circulator is a piston-type forced transfer machine that circulates the circulating gas by reciprocating the piston in the cylinder. The piston shaft extends in the reciprocating direction of the piston and linearly moves the piston in the reciprocating direction. Equipped with a reciprocating mechanism for reciprocating the shaft, the opening on the reciprocating mechanism side of the cylinder is closed with a closing plate that penetrates the piston shaft, and the surface of the piston shaft that slidably passes through the closing plate is sealed with a seal Sealed to the structure. In this structure, the piston shaft that reciprocates in the direction of the central axis of the cylinder moves linearly along the inner surface of the seal provided in the through hole of the closing plate, and the surface of the piston shaft is moved to the inner surface of the seal. Slide in an airtightly sealed state. For this reason, the gas leak in the sliding part of a piston shaft and the obstruction | occlusion plate can be reduced extremely. Further, since the circulating machine is sealed in an airtight structure at the sliding portion between the surface of the piston shaft and the through hole of the closing plate, the sealing area to be hermetically sealed can be narrowed, thereby improving the airtightness. Therefore, the spray drying apparatus that circulates the circulating gas through the circulator can effectively prevent external leakage of the solvent contained in the circulating gas and the raw material solution.

  A fourth circulation type spray drying apparatus of the present invention is the circulation type spray drying apparatus according to the first or second aspect, and includes a circulation path 8 for circulating a circulation gas to the spray drying tower 1. . The circulation path 8 includes a main circulation path 8A that circulates the gas discharged from the spray drying tower 1, and a first branch path 8B and a second branch path 8C that are connected to the discharge side of the main circulation path 8A. The first branch path 8B is connected to the gas compressor 4 and the tip thereof is connected to the nozzle 5, and the second branch path 8C is connected to the spray drying tower 1 without passing through the nozzle 5. Yes. Further, the main circulation path 8A or the second branch path 8C is connected to a circulation machine 6 for circulating the circulation gas. The circulation machine 6 is a diaphragm type forced transfer machine 6B, and the circulating gas is circulated to the spray drying tower 1 by the diaphragm type forced transfer machine 6B.

  The above circulation type spray drying apparatus includes a circulation path for circulating the circulation gas to the spray drying tower, and a circulation machine for circulating the circulation gas is connected to the circulation path so that the circulation machine is a diaphragm type. Since it is a forced transfer machine, the external leakage of the solvent contained in the circulating gas and raw material solution in the circulating machine can be reliably prevented. For this reason, this spray drying apparatus can prevent external leakage of the solvent contained in the circulating gas and the raw material solution while circulating the circulating gas to the spray drying tower with a circulator.

  The fifth circulation type spray drying apparatus of the present invention circulates the spray drying tower 1 that dries the mist of the raw material solution sprayed from the sprayer 9 to form fine particles, and the fine particles dried in the spray drying tower 1. A powder recovery unit 2 that separates and recovers from the gas, a condenser 3 that cools the circulating gas from which fine particles have been separated by the powder recovery unit 2 to liquefy and separate the solvent of the raw material solution, and a spray drying tower 1 A circulation path 8 that circulates the circulation gas discharged from the gas to the spray drying tower 1 via the powder recovery device 2 and the condenser 3, and a circulation device 6 that is connected to the circulation path 8 and circulates the circulation gas in the circulation path 8. And. The circulator 6 is a piston-type forced transfer machine 6A that circulates circulating gas by reciprocating the piston 41 in the cylinder 40. The circulator 6 includes a piston shaft 43 that extends in the reciprocating direction of the piston 41 and linearly moves in the reciprocating direction of the piston 41, and reciprocating mechanisms 34 and 24 that reciprocate the piston shaft 43. Further, the openings on the reciprocating mechanism 34, 24 side of the cylinder 40 are closed by a closing plate 47 having a through hole 47A through which the piston shaft 43 slidably passes. The closing plate 47 includes a seal 48 that seals the surface of the piston shaft 43 that is slidably passed through the through hole 47A in an airtight structure. The spray-drying apparatus circulates the circulating gas to the spray-drying tower 1 with the circulator 6 that is the above-described piston-type forced transfer machine 6A.

  The above-described circulation type spray drying apparatus has a unique structure in which the raw material solution sprayed from the sprayer is dried in the form of fine particles in the spray drying tower, and the circulating gas discharged from the spray drying tower is connected to the circulation path. By circulating to the spray-drying tower via a circulator, external leakage of the solvent contained in the circulating gas or the raw material solution can be effectively prevented. This circulator is a piston-type forced transfer machine that circulates the circulating gas by reciprocating the piston in the cylinder. The piston shaft extends in the reciprocating direction of the piston and linearly moves the piston in the reciprocating direction. Equipped with a reciprocating mechanism for reciprocating the shaft, the opening on the reciprocating mechanism side of the cylinder is closed with a closing plate that penetrates the piston shaft, and the surface of the piston shaft that slidably passes through the closing plate is sealed with a seal Sealed to the structure. The piston type forced transfer machine of this structure is such that the piston shaft that reciprocates in the direction of the center axis of the cylinder moves linearly along the inner surface of the seal provided in the through hole of the closing plate, and moves the surface of the piston shaft. Slide in an airtight seal on the inner surface of the seal. For this reason, the gas leak in the sliding part of a piston shaft and the obstruction | occlusion plate can be reduced extremely. Furthermore, since the piston-type forced transfer machine is hermetically sealed at the sliding portion between the surface of the piston shaft and the through hole of the closing plate, the hermetically sealed region can be narrowed, thereby improving the hermeticity. Therefore, the spray drying apparatus that circulates the circulating gas through the circulator composed of the piston-type forced transfer device can effectively prevent external leakage of the solvent contained in the circulating gas and the raw material solution.

  The sixth circulation type spray drying apparatus of the present invention circulates the spray drying tower 1 which dries the mist of the raw material solution sprayed from the sprayer 9 into fine particles, and the fine particles dried in the spray drying tower 1. A powder recovery unit 2 that separates and recovers from the gas, a condenser 3 that cools the circulating gas from which fine particles have been separated by the powder recovery unit 2 to liquefy and separate the solvent of the raw material solution, and a spray drying tower 1 A circulation path 8 that circulates the circulation gas discharged from the gas to the spray drying tower 1 via the powder recovery device 2 and the condenser 3, and a circulation device 6 that is connected to the circulation path 8 and circulates the circulation gas in the circulation path 8. And. The circulation machine 6 is a diaphragm type forced transfer machine 6B, and the diaphragm type forced transfer machine 6B circulates the circulating gas to the spray drying tower 1.

  The above circulation type spray drying apparatus dries the raw material solution sprayed from the sprayer into a fine particle form in the spray drying tower, and the circulation type exhaust gas connected from the spray drying tower is connected to the circulation path. Since it is circulated to the spray drying tower by the transfer device, external leakage of the solvent contained in the circulating gas and the raw material solution in the circulator can be reliably prevented. For this reason, this spray drying apparatus can prevent external leakage of the solvent contained in the circulating gas and the raw material solution while circulating the circulating gas to the spray drying tower with a circulator.

A seventh circulation type spray drying apparatus of the present invention is the circulation type spray drying apparatus according to any one of the first, third, and fifth aspects, and reciprocates between the gas compressor 4 and the circulator 6. The movement mechanisms 34 and 24 include a crank arm 42 that reciprocates the piston shaft 43, a connecting rod 46 that is formed by connecting the crank arm 42 to the piston shaft 43, and a drive mechanism 45 that rotates a rotating shaft 42A of the crank arm 42. Or a cam 26 that reciprocates the piston 41 and a drive mechanism 25 that rotates the cam 26.
The spray drying apparatus described above has a crank arm that is rotated by a drive mechanism as a reciprocating mechanism of a gas compressor or a circulator connected to a piston shaft via a connecting rod, or via a cam that is rotated by a drive mechanism. Since the piston shaft is reciprocated, the piston can be reciprocated by moving the piston shaft linearly in the axial direction of the cylinder with a simple mechanism.

The eighth circulation type spray drying apparatus of the present invention is the circulation type spray drying apparatus according to any one of the first, third, and fifth aspects, and includes piston type forced transfer machines 4A, 6A. The inside of the cylinder 40 is divided into a top dead center chamber 40X on the top dead center side of the piston 41 and a bottom dead center chamber 40Y on the bottom dead center side of the piston 41, and the top dead center chamber 40X and bottom dead center A path 39 that connects the point chamber 40Y is provided, and a check valve 38 that closes in the discharge stroke is provided in the path 39.
In the forced transfer machine described above, the circulation type spray drying device is surely closed while the path is blocked by a check valve in the discharge stroke for pressurizing the top dead center chamber, while pressurizing the circulating gas in the top dead center chamber. In the expansion stroke of the top dead center chamber, the circulating gas in the bottom dead center chamber can be passed through the path and moved to the top dead center chamber to prevent pressure from being applied to the bottom dead center chamber. Therefore, it is possible to reliably prevent the solvent contained in the circulating gas and the raw material solution from leaking to the outside.

A ninth circulation type spray drying apparatus of the present invention is the circulation type spray drying apparatus according to the eighth aspect, wherein the piston type forced transfer machines 4A and 6A are blocked from the bottom dead center of the cylinder 40. The exhaust port 40B is provided on the plate 47 side, the suction port 40A is provided on the closed end 40H side from the top dead center of the cylinder 40, or the suction port 40A is provided on the closed plate 47 side from the bottom dead center of the cylinder 40. The exhaust port 40B is provided on the closed end 40H side of the top dead center of the cylinder 40.
In the above circulation type spray drying apparatus, gas is sucked into the expanding chamber from the suction port in the exhaust stroke in which the chamber provided with the exhaust port is pressurized and the circulating gas is pushed out, so that the negative pressure is applied to the chamber provided with the suction port. Is effectively prevented, and the load acting on the piston can be reduced.

A tenth circulation type spray drying apparatus of the present invention is the circulation type spray drying apparatus according to any one of the first to ninth aspects, wherein the piston type forced transfer machines 4A and 6A are a plurality of cylinders. 40.
Since the above forced transfer machine includes a plurality of cylinders, the circulation amount of the circulating gas can be increased.

  An eleventh circulation type spray drying apparatus of the present invention is the circulation type spray drying apparatus according to any one of the third to tenth aspects, wherein the circulation unit 6 is arranged on the supply side of the condenser 3. ing.

  A twelfth circulation type spray drying apparatus of the present invention is the circulation type spray drying apparatus according to any one of the first to eleventh aspects, wherein the circulation gas is any one of nitrogen, helium, argon, and carbon dioxide gas. I am trying.

  A thirteenth circulation type spray drying apparatus of the present invention is the circulation type spray drying apparatus according to any one of the first to twelfth aspects, wherein the solvent of the raw material solution is alcohol.

 A fourteenth circulation type spray drying apparatus of the present invention is the circulation type spray drying apparatus according to any one of the first to thirteenth aspects, and guides the piston shaft 43 to the piston shaft 43 in a linear motion. The linear motion mechanism 60 is connected.

It is a schematic block diagram of the conventional circulation type spray-drying apparatus. It is a schematic block diagram of the other conventional circulation type spray-drying apparatus. It is a schematic block diagram of the circulation type spray-drying apparatus concerning one Example of this invention. It is a schematic block diagram which shows an example of a piston type forced transfer machine. It is a schematic block diagram which shows another process of the piston type forced transfer machine shown in FIG. It is a schematic block diagram which shows another example of a piston type forced transfer machine. It is a schematic block diagram which shows another process of the piston type forced transfer machine shown in FIG. It is a schematic block diagram which shows another example of the reciprocation mechanism of a piston type forced transfer machine. It is a schematic block diagram which shows another process of the reciprocating mechanism shown in FIG. It is a schematic block diagram which shows an example of a diaphragm type forced transfer machine. It is an expanded sectional view showing an example of a nozzle. It is a schematic block diagram of the circulation type spray-drying apparatus concerning the other Example of this invention. It is a schematic perspective view which shows an example of a sprayer.

  Embodiments of the present invention will be described below with reference to the drawings. However, the embodiment shown below exemplifies a circulation type spray drying apparatus for embodying the technical idea of the present invention, and the present invention does not specify the circulation type spray drying apparatus as follows. . Further, this specification does not limit the members shown in the claims to the members of the embodiments.

The circulation type spray drying apparatus shown in FIG. 3 is a spray drying tower 1 that dries the mist of the raw material solution sprayed from the nozzle 5 through the circulation gas to form fine particles, and the fine particles dried in the spray drying tower 1. Is recovered from the circulating gas, the condenser 3 that cools the circulating gas from which the fine particles have been separated by the powder collector 2 to liquefy and separate the solvent of the raw material solution, and the condensation The gas compressor 4 that pressurizes the circulating gas from which the solvent has been separated in the vessel 3 and supplies the pressurized gas to the nozzle 5 of the spray drying tower 1, the circulator 6 that circulates the gas, and the circulating gas that is sent to the spray drying tower 1 is heated And a pressure adjusting mechanism 16 for adjusting the circulating gas pressure. These spray drying apparatuses pressurize the circulating gas discharged from the condenser 3 by the gas compressor 4 and supply the pressurized gas to the nozzle 5, and use the circulating gas supplied to the nozzle 5 to feed the raw material solution into the spray drying tower 1. The sprayed mist is dried into fine particles by the spray drying tower 1 to form fine particles.
In the circulation type spray drying apparatus, the circulator 6 is intended to circulate the gas. Therefore, if the gas can be circulated, the place where the circulator 6 is installed is not specified. Thus, it is generally arranged before and after the condenser 3.

  The spray drying apparatus shown in FIG. 3 includes a circulation path 8 that circulates a circulating gas to the spray drying tower 1 and a pressure adjustment mechanism 16 that is connected to the circulation path 8. The circulation path 8 in the figure includes a main circulation path 8A for circulating the gas discharged from the spray drying tower 1, and a first branch path 8B and a second branch path connected to the discharge side of the main circulation path 8A. 8C is provided.

  The main circulation path 8A connects the pressure adjustment mechanism 16 to control the pressure of the circulating gas to be circulated. The pressure adjustment mechanism 16 adjusts the pressure in the main circulation path 8A so that the discharge side of the circulator 6 is at atmospheric pressure or the suction side is at atmospheric pressure.

  The main circulation path 8A is arranged on the discharge side of the spray drying tower 1 to connect the powder recovery unit 2 and the condenser 3, and on the discharge side of the condenser 3, the first branch path 8B and the second branch path 8A are connected. The branch path 8C is connected. The main circulation path 8 </ b> A in the figure is connected to a circulation machine 6 that circulates a circulation gas through the circulation path 8 on the discharge side of the powder recovery unit 2 and on the supply side of the condenser 3. However, the circulator can also be connected to the discharge side of the condenser. The first branch path 8 </ b> B and the second branch path 8 </ b> C are arranged on the discharge side of the condenser 3 and on the supply side of the spray drying tower 1. The first branch path 8 </ b> B connects the gas compressor 4 and connects the tip thereof to the nozzle 5. The second branch path 8 </ b> C is connected to the spray drying tower 1 without passing through the nozzle 5. The second branch 8 </ b> C in the figure includes a heater 7 that heats the circulating gas supplied to the spray drying tower 1. This spray drying apparatus circulates the circulating gas discharged from the spray drying tower 1 and circulated in the circulation path 8 to the spray drying tower 1 via the circulator 6, and further the circulating gas discharged from the condenser 3. A part is pressurized by the gas compressor 4 and supplied to the nozzle 5 of the spray drying tower 1.

  The spray drying tower 1 includes a closed chamber 10, and a nozzle 5 that atomizes the raw material solution into a mist and sprays the upper portion of the chamber 10. The spray-drying tower 1 shown in the figure is provided with a chamber 10 that is closed as a taper that narrows the lower part of the cylinder downward, and has a discharge port 11 that discharges dried fine particles and circulating gas at the lower end. Provided. The spray drying tower 1 shown in FIG. 3 is provided with a partition wall 12 that divides the chamber 10 up and down in the upper part of the chamber 10, and a drying chamber that dries mist sprayed from the nozzle 5 below the partition wall 12. 10A, and the upper part of the partition wall 12 is a reflux chamber 10B to which a circulating gas circulated by the circulator 6 is supplied. The spray-drying tower 1 has a through hole 12A opened at the center of the partition wall 12, and the nozzle 5 is disposed downward in the center of the through hole 12A. This spray drying tower 1 dries the mist of the raw material solution sprayed from the nozzle 5 to the drying chamber 10A with the heated circulating gas flowing into the drying chamber 10A from the through-hole 12A of the partition wall 12 into fine particles, The fine particles are discharged together with the circulating gas from the discharge port 11 at the lower end. The spray drying tower 1 shown in FIG. 3 heats the circulating gas supplied from the circulator 6 with a heater 7 and efficiently dries the mist of the raw material solution in the drying chamber 10 </ b> A with the heated circulating gas. To make fine powder. As shown in FIG. 3, the spray drying apparatus for circulating the circulating gas heated by the heater 7 to the spray drying tower 1 can be heated by providing a heater in the chamber, although not shown.

  The nozzle 5 injects the pressurized circulating gas supplied from the gas compressor 4 to atomize the raw material solution into mist and spray it. In the spray drying apparatus shown in the figure, a solution tank 14 storing a raw material solution is connected to a nozzle 5 of a spray drying tower 1 via a pump 15, and the pump 15 is operated to feed the raw material from the solution tank 14 to the nozzle 5. Supplying liquid. Further, the nozzle 5 is connected to the gas compressor 4. The nozzle 5 atomizes the raw material liquid supplied from the solution tank 14 into mist with the pressurized circulating gas supplied from the gas compressor 4 and sprays it into the spray drying tower 1.

  The mist of the raw material solution sprayed from the nozzle 5 is vaporized into the fine particles by evaporating the solvent of the raw material solution in the spray drying tower 1. The solvent of the raw material solution is an alcohol such as ethanol. However, the solvent of the raw material solution may be other than alcohol. In the spray drying tower 1, the fine particles obtained by vaporizing the solvent of the raw material solution are transferred to the powder recovery unit 2 together with the circulating gas. In the spray drying tower 1, it is not always necessary to completely dry all the mist sprayed from the nozzle 5 into fine particles. In the powder recovery device 2, which is the next step, undried mist is removed. Dry to fine particles. Accordingly, a part of the mist that is in an undried state in the spray drying tower 1 is also transferred to the powder recovery unit with the circulating gas together with the dried fine particles.

The powder collector 2 collects the fine particles dried in the spray drying tower 1 by separating them from the circulating gas. The powder collector 2 shown in the figure is a cyclone 20. The cyclone 20 in the figure is cylindrical, and the lower part of the cylinder is a tapered part that narrows downward. The cyclone 20 has an exhaust port 21 for discharging circulating gas at the center of the top plate, and an exhaust port 22 for discharging fine particles separated from the circulating gas at the lower end of the tapered portion. The cyclone 20 rotates the supplied circulating gas in a horizontal plane to centrifuge the fine particles from the circulating gas. Accordingly, the cyclone 20 opens the inlet 23 through which the circulating gas containing fine particles flows in the tangential direction. The fine particles that flow in from the inlet 23 and rotate inside the cyclone 20 are accelerated outward by receiving centrifugal force, fall along the inner surface of the cyclone 20, and are discharged from the lower discharge port 22. The circulating gas is discharged from the upper exhaust port 21. Furthermore, the powder recovery device 2 which is the cyclone 20 dries the mist in an undried state contained in the circulating gas discharged from the spray drying tower 1 and vaporizes the solvent to form fine particles. The vaporized solvent is exhausted from the upper exhaust port 22 together with the circulating gas.
The powder recovery device 2 can also be implemented using a filter such as a bag filter.
In the present invention, the powder recovery device is intended to separate the powder from the circulating gas. Therefore, if the powder can be separated from the circulating gas, the present invention is carried out even if the method used is other than the above. There is no problem in doing.

  The condenser 3 is connected to the discharge side of the powder recovery unit 2 and separates the vaporized solvent contained in the circulation gas from which fine particles have been separated by the powder recovery unit 2 from the circulation gas. The condenser 3 cools the circulating gas discharged from the powder recovery unit 2 and liquefies and separates the solvent of the raw material solution in a gaseous state. The condenser 3 shown in the figure incorporates a cooling heat exchanger 30 for cooling the circulating gas. The cooling heat exchanger 30 has fins (not shown) fixed to the heat exchange pipe 31. A cooling refrigerant or cooling water is circulated through the heat exchange pipe 31 to cool the cooling heat exchanger 30. In the mist of the raw material solution sprayed from the nozzle 5, the solvent is vaporized into fine particles, and the vaporized solvent is turned into a gas and circulated together with the circulating gas. The solvent in the gaseous state contained in the circulating gas is cooled and liquefied by the cooling heat exchanger 30 of the condenser 3, and the liquefied droplets are aggregated and collected. The circulating gas from which the solvent has been separated by the condenser 3 is circulated again to the spray drying tower 1.

  The purpose of the condenser 3 is to collect the vaporized solvent from the circulating gas, so that the heat exchanger to be used is not limited to the above type as long as the solvent can be condensed. Also, as a condensation method, depending on the type of solvent to be recovered, a method such as absorption by activated carbon or silica gel, or a method of absorbing it by dissolving in a liquid can be considered. Even if it exists, there is no problem in implementing the present invention.

  The gas compressor 4 pressurizes the circulating gas from which the solvent has been separated by the condenser 3 and supplies the pressurized gas to the nozzle 5 of the spray drying tower 1. This gas compressor 4 is a piston-type forced transfer machine 4A. However, instead of the piston-type forced transfer machine, a diaphragm-type forced transfer machine, which will be described later, can also be used. Enlarged sectional views of the piston-type forced transfer machine 4A are shown in FIGS.

  A compressor, which is a conventional piston-type gas compressor, converts a rotary motion of a motor or the like into a reciprocating motion by a crank and a connecting rod, and reciprocates the piston up and down. With this construction, the hermetic seal is performed at the piston portion. In the present invention, piston-type forced transfer machines 4A and 6A used for the gas compressor 4 and the circulator 6 have a piston shaft 43 that linearly moves in the longitudinal direction between the piston 41 and the connecting rod 46. Yes. Furthermore, the piston type forced transfer machines 4 </ b> A and 6 </ b> A shown in the drawing connect the linear motion mechanism 60 to the piston shaft 43.

  The linear motion mechanism 60 includes a pair of guide rods 61 fixed to the closing plate 47 of the cylinder 40 and a slide base 62 that reciprocates along the guide rods 61. The guide rods 61 are on both sides of the piston shaft 43 and are fixed in the reciprocating motion direction of the piston shaft 43. The slide base 62 is fixed to the lower end of the piston shaft 43 and connected so that the upper end of the connecting rod 46 can be tilted. The slide base 62 is connected so as to be movable along the guide rod 61 via a linear motion bearing 63 or a sliding metal.

  In the piston-type forced transfer machines 4A and 6A described above, the reciprocating motion generated in the crank mechanism including the crank arm 42, the crank pin 42B, and the connecting rod 46 as the rotating shaft 42A is rotated by the motor 45 causes the piston shaft 43 to move. This is transmitted to the piston shaft 43 through a linear motion mechanism 60 composed of a guide rod 61 and a slide base 62, and moves the piston 41 up and down. Unlike the conventional piston type compressor, the above-mentioned forced transfer machine linearly moves the piston shaft 43 connected to the piston 41. Since the piston shaft 43 moves linearly, unlike the conventional piston type compressor, as shown in FIG. 5, in addition to the piston portion, the piston shaft 43 can also be sealed.

  The seal of the piston shaft 43 includes a pressure seal 48B on the piston side and an oil seal 48A on the rotating shaft 42A side, and is attached to a closing plate 47 that closes the lower portion of the cylinder 40. The linear motion mechanism 60 that guides the piston shaft 43 in a linear motion is not limited to a mechanism that causes the guide rod 61 to reciprocate the slide base 62, but may be any mechanism that linearly moves the piston shaft.

  The gas compressor 4 of the piston type forced transfer machine 4A described above can seal the piston shaft 43 in an airtight manner and prevent leakage of circulating gas. Since the diameter of the piston shaft 43 can be made significantly smaller than that of the piston 41, the seal used for the piston shaft 43 can be realized in a very narrow region. Since the piston shaft 43 can be sealed in a narrow region and leakage of the circulating gas can be prevented, the above-mentioned forced transfer machine can obtain a high sealing effect, and as a result, a very high airtightness can be realized.

  The piston type forced transfer machine 4A shown in FIGS. 4 to 7 reciprocates the piston 41 in the cylinder 40 to transfer the circulating gas. The piston-type forced transfer machine 4 </ b> A shown in the drawing reciprocates in and out of the cylinder 40, which sucks circulating gas through the check valve 44 and discharges the sucked circulating gas through the check valve 44. A piston 41 that moves, a piston shaft 43 that extends in the reciprocating direction of the piston 41, linearly moves in this direction, and reciprocates the piston 41, and a reciprocating mechanism 34 that reciprocates the piston shaft 43 are provided. ing.

  The cylinder 40 has a top dead center chamber 40X on the top dead center side of the piston 41 and a bottom dead center chamber 40Y on the opposite side of the top dead center chamber 40X and on the bottom dead center side of the piston 41. In addition, it is partitioned by a piston 41. In the illustrated cylinder 40, the end on the top dead center chamber side is closed with a closed end 40H, and the end on the bottom dead center chamber side is closed with a closing plate 47 having a through hole 47A through which the piston shaft 43 passes. . 4 and 5 extrudes the circulating gas in the top dead center chamber 40X and sucks the circulating gas in the bottom dead center chamber 40Y. 6 and 7 sucks the circulating gas in the top dead center chamber 40X and pushes the circulating gas out in the bottom dead center chamber 40Y.

  The cylinder 40 has a vent hole on the closed end 40H side from the top dead center of the piston 41 that reciprocates and on the closed plate 47 side from the bottom dead center. In the cylinder 40 of FIGS. 4 and 5, the vent hole of the top dead center chamber 40X is an exhaust port 40B, and the vent hole of the bottom dead center chamber 40Y is an inlet port 40A. In the cylinder 40 of FIGS. 6 and 7, the vent hole of the top dead center chamber 40X is an intake port 40A, and the vent hole of the bottom dead center chamber 40Y is an exhaust port 40B. The suction port 40A is connected to a suction valve 44A, which is a check valve 44 that allows the circulating gas to pass through the cylinder 40 in the direction of sucking the circulating gas. The exhaust port 40B is connected to a discharge valve 44B, which is a check valve 44 that allows the circulating gas to pass only in the direction of discharging the circulating gas from the cylinder 40. The cylinder 40 of the gas compressor 4 connects the suction port 40A to the discharge side of the condenser 3 via the suction valve 44A, and connects the exhaust port 40B to the nozzle 5 via the discharge valve 44B.

  The piston 41 has a cylindrical shape that reciprocates within the cylinder 40. The piston 41 has a piston shaft 43 connected to the center of the cylinder 40 on the closing plate 47 side, and reciprocates through the piston shaft 43. In the illustrated piston 41, the piston ring 41B is disposed on the outer periphery of the piston 41 to improve the airtightness of the cylinder 40 in order to reduce the leakage of circulating gas from the cylinder 40.

  Further, the piston 41 is provided with a path 39 for connecting the top dead center chamber 40X and the bottom dead center chamber 40Y in order to prevent pressure on the closing plate 47 in a state of reciprocating in the cylinder 40. Yes. A check valve 38 is provided in this path 39. The check valve 38 shown in FIGS. 4 and 5 is closed in the stroke in which the piston 41 moves from the bottom dead center toward the top dead center, that is, in the discharge stroke of the top dead center chamber 40X. The valve is opened in the intake stroke that moves from the bottom to the bottom dead center.

  4 and 5, as shown in a partial cross-sectional view, a through hole penetrating in the axial direction is provided as a path 39. The piston 41 shown in the drawing is provided with a valve body 38A for closing the opening of the path 39 so as to be openable and closable on the end surface on the top dead center chamber 40X side, so that the gas passes only toward the top dead center chamber 40X. The valve 38 is used. As shown by an arrow B in FIG. 5, the check valve 38 opens the valve body 38A to open the valve body 38A from the top dead center toward the bottom dead center. The gas in the bottom dead center chamber 40Y on the side is moved to the top dead center chamber 40X to prevent the bottom dead center chamber 40Y from being pressurized. For this reason, it is possible to reliably prevent the solvent contained in the circulating gas and the raw material solution from leaking to the outside from the seal portion of the piston shaft 43 in the suction stroke in which the piston 41 is lowered.

  In addition, as shown by an arrow A in FIG. 4, the check valve 38 moves the piston 41 from the bottom dead center toward the top dead center, that is, in the discharge stroke, the valve body 38 </ b> A is an opening portion of the path 39. And the gas in the top dead center chamber 40X is discharged from the discharge valve 44B to the outside while being pressurized. In this exhaust stroke, the circulating gas is sucked into the bottom dead center chamber 40Y and is not decompressed, and gas leakage from the seal portion of the piston shaft 43 can be prevented also in this stroke.

  4A and 5B, the piston-type forced transfer machine 4A has a top dead center chamber on both sides of the piston 41 and on the closed end 40H side of the cylinder 40, instead of the piston path 39. A path 39 for connecting 40X and the bottom dead center chamber 40Y on the opening side may be provided outside the cylinder 40. This path 39 is also provided with a check valve 38. The path 39 is arranged so that one end is opened closer to the closed end 40H than the top dead center of the piston 41 and the other end is opened closer to the open end than the bottom dead center of the piston 41. The check valve 38 provided in this path 39 also permits the movement of gas from the bottom dead center chamber 40Y to the top dead center chamber 40X, but allows the movement of gas from the top dead center chamber 40X to the bottom dead center chamber 40Y. As a structure for blocking, that is, a structure that is closed when the top dead center chamber 40X is pressurized, pressure is prevented from being applied to the seal portion of the piston shaft 43 of the piston 41.

  The piston-type forced transfer machine 4A described above sucks the circulating gas through the check valve 44A during the discharge stroke in which the piston 41 rises. In the exhaust stroke, the circulating gas is sucked into the bottom dead center chamber 40Y. The gas sucked into the bottom dead center chamber 40Y is sent to the top dead center chamber 40X through the path 39 by opening the check valve 38 when the piston 41 descends. In the exhaust stroke in which the piston 41 rises again, the gas sent to the top dead center chamber 40X above the piston 41 is pressurized by the piston 41, passes through the check valve 44B, and is exhausted as compressed gas. It is sent to the nozzle 5.

  In the exhaust stroke in which the piston 41 rises, in the top dead center chamber 40X, the circulating gas is pressurized and the gas pressure rises, so that a large pressure is applied to the piston ring 41B. In contrast, in the bottom dead center chamber 40Y, even in the intake stroke in which the piston 41 descends, the internal gas passes through the check valve 38 opened with the passage 39 and escapes to the top dead center chamber 40X. Therefore, no large pressure is applied to the pressure seal 48B. Further, when the piston 41 moves up, gas is sucked into the bottom dead center chamber 40Y through the check valve 44A, so that a large negative pressure is not generated in the bottom dead center chamber 40Y. Therefore, as a result, a large positive and negative pressure does not act on the seal 48B between the piston shaft 43 and the closing plate 47, so that the gas compressor 4 can ensure high airtightness.

  The piston-type forced transfer machine 4A described above sucks the circulating gas into the bottom dead center chamber 40Y and discharges it from the top dead center chamber 40X. FIG. 6 and FIG. The forced transfer machine 6A is shown. The piston-type forced transfer machine 6A sucks the circulating gas into the top dead center chamber 40X and discharges it from the bottom dead center chamber 40Y. Therefore, the piston-type forced transfer machine 6A is provided with the suction port 40A in the top dead center chamber 40X and the exhaust port 40B in the bottom dead center chamber 40Y. This piston-type forced transfer machine 6A is provided with an exhaust port 40B on the opening end side of the bottom dead center of the piston 41 that reciprocates, and a discharge valve 44B is connected to the exhaust port 40B and the top dead center of the piston 41 A suction port 40A is provided closer to the closed end 40H than the point, and a suction valve 44A is connected to the suction port 40A.

  6 and 7 is provided with an exhaust port 40B at the opening end of the cylinder and an intake port 40A at the closed end 40H of the cylinder. Further, as shown in the partial cross-sectional view of the figure, the piston 41 is provided with a passage 39 that penetrates in the axial direction. The passage 39 is a check valve that is closed when the bottom dead center chamber 40X is pressurized. 38 is provided. The illustrated piston 41 is provided with a valve body 38A that can be opened and closed so that the opening on the bottom dead center chamber 40Y side of the path 39 can be opened and closed. The piston-type forced transfer machine 6A causes the piston 41 to discharge the gas in the bottom dead center chamber 40Y from the exhaust port 40B during the exhaust stroke in which the piston 41 is moved from the top dead center to the bottom dead center. The gas is sucked into the top dead center chamber 40X from the suction port 40A. Further, this piston-type forced transfer machine 6A raises the piston 41 from the bottom dead center toward the top dead center, and in the top dead center chamber 40X during the suction stroke of sucking the circulating gas into the bottom dead center chamber 40Y. Gas is allowed to flow into the bottom dead center chamber 40Y via the path 39.

  In the piston-type forced transfer machine 6A, in the discharge stroke in which the piston 41 is lowered, the passage 39 is closed by the check valve 38, the gas in the bottom dead center chamber 40Y is discharged by the piston 41, and the piston 41 is discharged. In the ascending suction stroke, the gas in the top dead center chamber 40X is passed through the path 39 and flows into the bottom dead center chamber 40Y.

  The piston-type forced transfer machine 6A described above is provided with a path 39 having a check valve 38 in the piston 41 to prevent the ascending piston 41 from depressurizing the bottom dead center chamber 40Y. Instead of this, a path 39 can be provided outside the cylinder 40 as shown by the broken line in the figure. The path 39 is provided with a check valve 38. The check valve 38 transfers the circulating gas only from the top dead center chamber 40X toward the bottom dead center chamber 40Y. The path 39 has one end connected to the top dead center chamber 40X and the other end connected to the bottom dead center chamber 40Y. The connecting portion that connects the path 39 to the top dead center chamber 40X is always connected to the top dead center chamber 40X even when the piston 41 reciprocates, that is, the closed end 40H side from the top dead center of the piston 41. Is located. In addition, the connecting portion that connects the path 39 to the bottom dead center chamber 40Y is always connected to the bottom dead center chamber 40Y even when the piston 41 reciprocates, that is, the closing plate is located at a position lower than the bottom dead center of the piston 41. 47 side.

  In the piston type forced transfer machine 6A, the check valve 38 is closed in the discharge stroke in which the piston 41 descends, and the piston 41 discharges the gas in the bottom dead center chamber 40Y from the exhaust port 40B. Gas is sucked into the top dead center chamber 40X from the suction port 40A. Further, in the piston type forced transfer machine 6A, in the process of raising the piston 41 in the drawing, the check valve 38 of the path 39 is opened, and the gas in the top dead center chamber 40X is passed through the path 39. Flow into the bottom dead center chamber 40Y. In the piston-type forced transfer machine 6A, the bottom dead center chamber 40Y is not decompressed during the upward stroke of the piston 41. For this reason, it is used in a state where the pressure on the discharge side of the bottom dead center chamber 40Y is set to atmospheric pressure, and there is a feature that the leakage of the seal portion of the piston shaft 43 can be reliably prevented. Therefore, the above-described piston-type forced transfer machine 6A is used in a state where the pressure on the discharge side is atmospheric pressure, and gas leakage can be effectively prevented.

  The piston shaft 43 is disposed at the center of the cylinder 40 so as to extend in the reciprocating direction of the piston 41, and the front end is connected and fixed to the piston 41, and the rear end is passed through the closing plate 47 and pulled out from the cylinder 40. ing. The piston shaft 43 slidably passes through a through hole 47A of a closing plate 47 that closes the opening of the cylinder 40. The closing plate 47 includes a seal 48 that seals the surface of the piston shaft 43 in an airtight structure. The seal 48 includes an oil seal 48A and a pressure seal 48B which are arranged in parallel in two rows, and the oil seal 48A is provided on the crank side and the pressure seal 48B is provided on the bottom dead center chamber 40Y side. The seal 48 is a rubber-like elastic O-ring. The O-ring seal 48 is disposed in the through hole 47A of the closing plate 47, and slidably penetrates the piston shaft 43. The seal 48 is a rubber-like elastic body such as Teflon (registered trademark), silicon, natural or synthetic rubber. The seal 48 is in close contact with the surface of the piston shaft 43, and the piston shaft 43 is reciprocated in a sliding state so that the sliding portion of the piston shaft 43 has an airtight structure, and the circulating gas leaks from this portion. Stop. However, a metal seal obtained by processing a metal such as copper, shinchu, aluminum, and stainless steel into a ring shape can also be used for the seal. The above-described piston shaft 43 is driven by the reciprocating mechanism 34 and linearly moves in the reciprocating direction of the piston 41 while holding the surface of the piston shaft 43 in a state of being hermetically sealed in the through hole 47 </ b> A via the seal 48. The piston shaft 43 is guided to linearly move by the linear motion mechanism 60.

  The linear motion mechanism 60 includes a pair of guide rods 61 fixed to the closing plate 47 of the cylinder 40 and a slide that reciprocates along the guide rods 61 in the same manner as the forced transfer machine shown in FIGS. And a base 62. The guide rods 61 are on both sides of the piston shaft 43 and are fixed in the reciprocating motion direction of the piston shaft 43. The slide base 62 is fixed to the lower end of the piston shaft 43 and connected so that the upper end of the connecting rod 46 can be tilted. The slide base 62 is connected so as to be movable along the guide rod 61 via a linear motion bearing 63 or a sliding metal.

  The reciprocating mechanism 34 reciprocates the slide base 62 that connects and fixes the rear end of the piston shaft 43 to reciprocate the piston shaft 43. A reciprocating mechanism 34 shown in FIGS. 6 and 7 includes a crank arm 42 that reciprocates a slide base 62 to which a piston shaft 43 is fixed, and the crank arm 42 connected to the piston shaft 43 via the slide base 62. A connecting rod 46 and a drive mechanism 45 for rotating the rotating shaft 42A of the crank arm 42. The crank arm 42 is connected to one end of the connecting rod 46 via a crank pin 42B. The connecting rod 46, one end of which is connected to the crank arm 42, is connected to the slide base 62, to which the piston shaft 43 is fixed, so that the other end can be tilted via a tilting shaft 43A. The drive mechanism 45 is a motor that rotates the rotating shaft 42 </ b> A that fixes the crank arm 42. As shown in FIGS. 4 and 5, the reciprocating mechanism 34 described above rotates the crank arm 42 with the drive mechanism 45, and reciprocates the slide base 62 in a straight line via the connecting rod 46 in the vertical direction in the figure. Let

  The piston shaft 43, which is guided by the linear motion mechanism 60 and reciprocated, is guided in the linear motion direction by the guide rod 61, and does not shake or vibrate except in the linear motion direction. For this reason, an unreasonable load does not act on the seal 48 and the piston ring 41B of the piston shaft 43, and the life of the seal 48 and the piston ring 41A can be extended to maximize the sealing effect. However, the present invention is not specified as a mechanism for reciprocating the piston shaft 43 via the linear motion mechanism 60, and is connected to one end of the crank arm so as to be able to rotate via a pin to linear motion mechanism. It is also possible to adopt a structure in which the piston shaft is reciprocated by the crank arm without going through.

  However, the reciprocating mechanism is not limited to the above structure, and as shown in FIGS. 8 and 9, the reciprocating mechanism includes a cam 26 that reciprocates the piston shaft 43 and a drive mechanism 25 that rotates the cam 26. You can also. The drive mechanism 25 is a motor that rotates the cam 26. The reciprocating mechanism 24 shown in the drawing reciprocates the piston shaft 43 with the cam 26 via the slide base 62. The rotating cam 26 reciprocates the slide base 62 and reciprocates the piston shaft 43 with the slide base 62. In the illustrated reciprocating mechanism 24, the cam 26 reciprocates the piston shaft 43 via the slide base 62. In order to elastically press the slide base 62 against the surface of the cam 26, an elastic body 27 is provided. The elastic body 27 is a pressing spring of the coil spring 27 </ b> A and is between the slide base 62 and the closing plate 47 and elastically presses the slide base 62 toward the cam 26. The elastic body of the coil spring can be provided between the closing plate and the slide base so as to pass through the guide rod. The reciprocating mechanism 24 having this structure moves the rear end of the piston shaft 43 along the outer peripheral surface of the cam 26 rotated by the motor that is the driving mechanism 25 to reciprocate the piston shaft 43.

  In the piston-type forced transfer machines 4A and 6A described above, the piston shaft 43 reciprocated by the reciprocating mechanisms 34 and 24 causes the piston 41 in the cylinder 40 to reciprocate. In the piston-type forced transfer machines 4A and 6A, when the piston 41 reciprocates in the cylinder 40, the circulating gas is sucked into the cylinder 40 through the suction valve 44A and is circulated in the cylinder 40 through the discharge valve 44B. The gas is discharged under pressure. The piston-type forced transfer machine 4 </ b> A that is the gas compressor 4 includes a rotation speed adjustment mechanism 49 that changes the pressure of the circulating gas blown to the nozzle 5. A rotation speed adjustment mechanism 49 shown in the drawing is an inverter that controls the operation of the motors that are the drive mechanisms 45 and 25. The rotation speed adjustment mechanism 49 controls the rotation speed of the motor with an inverter to adjust the pressure of the circulating gas supplied to the nozzle 5 by the piston-type forced transfer machine 4 </ b> A that is the gas compressor 4.

  Further, the piston type forced transfer machines 4A and 6A described above do not cause the piston shaft 43 to be laterally shaken with respect to the through hole 47A of the closing plate 47, that is, along the inner surface of the seal 48 provided in the through hole 47A. The surface of the piston shaft 43 is slid in a state of being hermetically sealed with the inner surface of the seal 48. For this reason, the gas leak in the sliding part of the piston shaft 43 and the obstruction | occlusion plate 47 can be reduced extremely. Further, the piston type forced transfer machines 4A and 6A described above are sealed in an airtight structure at the sliding portion between the surface of the piston shaft 43 and the through hole 47A of the closing plate 47. Compared with a structure in which the outer peripheral surface of the piston 41 is sealed in an airtight structure, the airtightly sealed region can be narrowed, thereby improving the airtightness. Therefore, by using this piston-type forced transfer machine 4A as the gas compressor 4, external leakage of the solvent contained in the circulating gas and the raw material solution can be effectively prevented.

  The piston-type forced transfer machines 4A and 6A described above include a cylinder 40 of one cylinder. However, the piston-type forced transfer machine can also include a plurality of cylinders, that is, two or more cylinders 40.

  The gas compressor 4 described above is a piston-type piston-type forced transfer machine 4A, but the gas compressor 4 may be a diaphragm-type forced transfer machine 4B. A diaphragm type forced transfer machine 4B is shown in FIG. A diaphragm-type forced transfer machine 4B shown in this figure includes a cavity 50 that sucks circulating gas through a check valve 54 and discharges the sucked circulating gas through the check valve 54, and the inside of the cavity 50 And a drive mechanism 55 for reciprocating the diaphragm 51.

  The diaphragm type forced transfer machine 4B shown in the drawing divides the inside of the cavity 50 into two parts, and fixes the diaphragm 51 between the two cavities 50X and 50Y. One cavity 50X has air inlets at two locations at the bottom, and is provided with an inlet 50A and an outlet 50B. The suction port 50A is connected to a suction valve 54A that is a check valve 54 that allows the circulating gas to pass in the direction of sucking the circulating gas into the cavity 50X. The exhaust port 50B is connected to a discharge valve 54B that is a check valve 54 that allows the circulating gas to pass only in the direction of discharging the circulating gas from the cavity 50A. The cavity 50 </ b> A connects the suction valve 54 </ b> A to the discharge side of the condenser 3 and connects the discharge valve 54 </ b> B to the supply side of the nozzle 5.

  The diaphragm 51 is arranged between the two cavities 50X and 50Y so that the inside of the cavity 50 is hermetically defined and can reciprocate inside the cavity 50. The diaphragm-type forced transfer machine 4B shown in the drawing has a drive mechanism 55 as an electromagnet 56, and controls the electromagnet 56 to be turned on and off, and a state in which the electromagnet 56 magnetically attracts the diaphragm 51 and a state in which the diaphragm 51 is restored to its original position. Repeatedly inhales and exhausts circulating gas. This drive mechanism 55 controls the on / off of the electromagnet with the control circuit 57 to adjust the vibration period of the diaphragm, and adjusts the pressure of the circulating gas supplied to the nozzle 5 by the diaphragm type forced transfer machine 4B. However, the drive mechanism for reciprocating the diaphragm is not specified as an electromagnet. As the drive mechanism, any other mechanism that can reciprocate the diaphragm can be used. Since the diaphragm type forced transfer machine 4B does not have a sliding portion like the piston type forced transfer machine 4A, it can be discharged while pressurizing the circulating gas while reliably preventing the circulating gas from leaking.

  As shown in FIG. 3, the circulator 6 is arranged in the circulation path 8 to circulate the circulation gas to the circulation path 8. As the circulator 6, the same structure as the air compressor 4 shown in FIGS. 4 to 10 can be used. That is, the circulator 6 can be a piston-type forced transfer machine 6A shown in FIGS. 4 to 9, or a diaphragm-type forced transfer machine 6B as shown in FIG.

The circulation machine 6 is intended to circulate the gas in the circulation type spray drying apparatus. Therefore, if the gas can be circulated, the place to be installed is not specified. Downstream of the condenser 3 and before and after the condenser 3.
In order to condense the solvent from the gas, the higher the gas pressure, the higher the condensation efficiency, that is, the recovery efficiency. Therefore, it is desirable to arrange the circulator 6 on the upstream side of the condenser 3 and to blow the circulating gas to the condenser 3 in a pressurized state. However, if the circulator 6 has low airtightness, the concentration of the solvent before condensation is low. Since the high gas flows out to the outside and the solvent recovery rate is significantly impaired, the circulator is preferably installed downstream of the condenser. However, since the circulator 6 used in the circulation type spray drying apparatus of the present invention is highly airtight and has almost no outflow of gas, the circulator 6 can be disposed upstream of the condenser 3. As a result, condensation with a high gas pressure, that is, condensation with a high recovery rate can be realized.

The circulator 6 in the figure can change the flow rate of the circulating gas blown to the circulation path 8 by adjusting the rotation speed of the crankshaft which is the rotation shaft 42A of the crank arm 42. The piston-type forced transfer machine 6A shown in FIGS. 4 to 9 is provided with a rotation speed adjusting mechanism 49 that adjusts the flow rate and pressure of the circulating gas by adjusting the rotation speed of the crankshaft. The piston-type forced transfer device 6A used for the circulator 6 can control the flow rate of the circulating gas by adjusting the rotational speed of the crankshaft by the rotational speed adjusting mechanism 49. Therefore, the forced transfer machine of the circulator 6 can use the rotation speed adjustment mechanism 49 as a flow rate adjustment mechanism.
The flow rate adjustment mechanism of the rotation speed adjustment mechanism 49 controls the rotation speed of the motor with an inverter to adjust the flow rate of the circulating gas that the circulator 6 circulates in the circulation path 8.

  The circulating machine 6 sets the flow rate of the circulating gas to 5 to 20 times, preferably 10 to 15 times the flow rate of the air compressor 4. The circulator can adjust not only the number of rotations of the motor, which is a drive mechanism, but also the flow rate by variously designing the inner diameter of the cylinder and the stroke for reciprocating the piston.

  The circulator 6 including the piston-type forced transfer machine 6A described above can circulate the circulating gas while effectively preventing external leakage of the solvent contained in the circulating gas and the raw material solution.

Since the circulation type spray drying equipment has the feature that the solvent is not leaked to the outside by spraying the liquid raw material with the organic solvent as the solvent, the inert gas is used as the circulation gas to explode or burn the volatilized organic solvent. To prevent. Therefore, when operating a circulation type spray drying apparatus, the pressure of the suction port portion of the circulator 6 where the internal pressure of the circulating gas is the lowest is large in order to prevent outside air from being sucked into the circulating gas. The pressure in the circulation path 8 is adjusted by the pressure adjusting mechanism 16 so as not to drop below the atmospheric pressure. In such a case, the circulation machine 6 has a structure on the premise that the discharge pressure becomes a positive pressure as shown in FIGS.
On the other hand, although it is very rare, the powder to be spray-dried and the liquid raw material are special, and it is not necessarily the case that the conditions for spray-drying have to be performed at a negative pressure rather than an atmospheric pressure. In such a case, the circulator 6 is required to have a structure that eliminates atmospheric suction rather than outflow of the circulating gas. In this case, since the absolute value of the suction negative pressure is larger than the discharge pressure, the airtight structure on the suction side is important. Therefore, in the piston-type forced transfer machine 6A having the structure shown in FIGS. 4 and 5, the top dead center chamber 40X has high airtightness.
As shown in FIGS. 6 and 7, the circulator 6, which is a piston-type forced transfer machine 6A used for this purpose, draws a circulating gas lower than the atmospheric pressure into the top dead center chamber 40X and lowers it. As a structure for discharging from the dead center chamber 40Y, it is possible to more reliably prevent air from being sucked into the circulating gas.

  Furthermore, instead of the piston-type forced transfer machine 6A, a diaphragm-type forced transfer machine 6B can be used as the circulation machine 6. As the diaphragm type forced transfer machine 6B, a forced transfer machine having the same structure as the structure shown in FIG. The circulator 6 including the diaphragm type forced transfer device 6B does not have a sliding portion like the piston type forced transfer device 6A, and therefore can circulate the circulating gas while reliably preventing the circulating gas from leaking.

  As shown in FIG. 3, the heater 7 is disposed on the discharge side of the circulator 6, and heats the circulating gas refluxed to the spray drying tower 1 via the circulator 6. The heater 7 shown in FIG. 3 is an electric heater that controls the temperature at which the circulating gas is heated by controlling the power supplied by the control circuit 35. The spray drying apparatus shown in FIG. 3 has a temperature detection unit 36 connected to the circulation path 8 on the discharge side of the heater 7, and the temperature detection unit 36 detects the temperature of the circulating gas returned to the spray drying tower 1. Yes. The control circuit 35 controls the heater 7 based on the input signal from the temperature detection unit 36 to control the temperature of the circulating gas to the optimum temperature. However, the heater is not limited to an electric heater, and can be any other mechanism capable of heating the circulating gas circulated in the circulation path.

  The above spray drying apparatus preferably uses an inert gas such as nitrogen, helium or argon as the circulating gas. In this spray drying apparatus, particulates separated from the raw material solution and alteration of the solvent are prevented by the inert circulating gas. For this reason, fine particles can be collected in a higher quality state. However, carbon dioxide gas or air can also be used as the circulating gas. As shown in FIG. 3, the circulating gas is supplied to the circulation path 8 via the pressure adjustment mechanism 16.

  Although not shown, the pressure adjusting mechanism 16 includes a pressure sensor for measuring the gas pressure of the circulating gas, a pressure reducing control valve for discharging and reducing the pressure of the circulating gas, and an inert gas supply means such as an inert gas cylinder. It is implemented by a control means comprising an introduction control valve for controlling the introduction amount of the inert gas and a decompression control valve, a sequencer for controlling the introduction control valve or a microcomputer according to the value of the pressure sensor.

  The above spray-drying apparatus supplies the circulating gas pressurized from the gas compressor 4 to the nozzle 5, and the nozzle 5 atomizes the raw material solution into the mist and sprays it. As this nozzle 5, one having the structure shown in FIG. 11 can be used. The nozzle 5 in FIG. 11 is provided with a supply port 82 for injecting the raw material liquid in a ring shape. The nozzle 5 is provided with an inner ring 91, an intermediate ring 92, and an outer ring 93 in order from the center. The nozzle 5 is provided with an injection path 94 for circulating gas inside the inner ring 91, a solution path 96 for raw material solution between the inner ring 91 and the intermediate ring 92, and between the intermediate ring 92 and the outer ring 93. Also, a circulation gas injection path 95 is provided. The injection paths 94 and 95 and the solution path 96 are ring-shaped, the circulating gas is injected from the injection paths 94 and 95, and the raw material solution is injected from the intermediate solution path 96 in a ring shape. The raw material solution injected from the solution path 96 is atomized into mist by circulating gas injected from both sides. In particular, the nozzle 5 has a sharp shape with the inner peripheral surface of the inner ring 91 and the inner peripheral surface of the intermediate ring 92 as a smooth surface, and a circulating gas is allowed to flow at a high speed on both the inner and outer surfaces. Collide with circulating gas. For this reason, the raw material solution supplied from the solution path 96 is crushed into fine mist at the tips of the inner ring 91 and the intermediate ring 92. The nozzle 5 brings the raw material solution and the circulating gas into contact in an ideal state at the gas-liquid interface at the tip portions of the inner ring 91 and the intermediate ring 92 and quickly atomizes the raw material solution into fine particles.

  The inner ring 91 has a cylindrical outer shape, the intermediate ring 92 has an inner shape processed into a cylindrical shape, and a slit-shaped solution path 96 having a predetermined width is provided between the inner ring 91 and the intermediate ring 92. The solution path 96 is formed in a ring shape, and the slit width is designed such that the raw material solution is not clogged. The nozzle 5 does not need to send out the raw material solution from the solution path 96 as a thin film. This is because the raw material solution is thinly stretched on the smooth surface 87 and sprayed as fine particles. Therefore, the slit width of the solution path 96 is designed to an optimum value in consideration of the flow rate of the raw material solution to be delivered, the length of the smooth surface 87, the flow rate of the circulating gas injected onto the smooth surface 87, the inner diameter of the solution path 96, and the like. Is done.

  The diameter of the solution path 96 is designed to an optimum value in consideration of the flow rate of the raw material solution to be injected, the dimension of the slit width, and the like. The diameter of the solution path 96 is designed to be, for example, about 50 mmφ in the nozzle 5 that injects a raw material solution of 1000 g / min. The solution path 96 is designed to have a larger diameter when the flow rate is larger, and smaller when the flow rate is smaller.

  The tip surfaces of the inner ring 91 and the intermediate ring 92 are cut into a tapered shape to form a smooth surface 87. The smooth surfaces 87 of the inner ring 91 and the intermediate ring 92 are flush with each other so that the flowing air injected along the smooth surface 87 of the inner ring 91 is not turbulent at the boundary between the inner ring 91 and the intermediate ring 92. Is formed. The smooth surface 87 of the inner ring 91 and the intermediate ring 92 is flush with the smooth surface 87 of the inner ring 91 and the intermediate ring 92, and the smooth surface 87 of the intermediate ring 92 from the smooth surface 87 of the inner ring 91. This means a state in which air flows linearly. Thus, in order to process the smooth surface 87 of the inner ring 91 and the intermediate ring 92 into a tapered shape on the same plane, the inner ring 91 and the intermediate ring 92 may be connected and tapered. Further, the smooth surface 87 is a smooth surface 87 along the flow direction of the raw material solution so that the raw material solution flowing along the surface does not become a turbulent flow. The smooth surface 87 of the nozzle 5 shown in FIG.

  By providing the smooth surface 87 on the inner ring 91 and the intermediate ring 92, the solution path 96 is opened in the middle of the smooth surface 87. The inclination angle α of the smooth surface 87 provided on the inner ring 91 and the intermediate ring 92 is, for example, 100 to 170 degrees, preferably 120 to 160 degrees, so that the angle of the solution path 96 with respect to the smooth surface 87 is obtuse. It is preferably designed at 140 to 160 degrees, and most preferably about 150 degrees. The larger the inclination angle α, the more stable the liquid outflow. However, the optimum value of the inclination angle α varies depending on the slit width. The inclination angle α is preferably designed so that the opening width of the solution path 96 in the smooth surface 87 does not exceed 2 mm.

  A center ring 90 is disposed at the tip of the inner ring 91, and an injection port 81 is opened between the tip of the center ring 90 and the inner ring 91. The center ring 90 has an outer peripheral surface processed into a tapered shape along the smooth surface 87 of the inner ring 91. An injection port 81 formed between the center ring 90 and the inner ring 91 has a slit shape, from which pressurized air is injected into a laminar flow state and flows at a high speed along the smooth surface 87.

  The injection path 94 of the inner ring 91 is connected to the air compressor 4. The supply port 82 injects a circulating gas that flows along the smooth surface 87. The air compressor 4 supplies, for example, 3 to 20 kg / cm 2, preferably 4 to 15 kg / cm 2, more preferably 4 to 10 kg / cm 2, and most preferably about 6.5 kg / cm 2 to the supply port 82. When the gas pressure of the circulating gas is increased, the flow rate of the circulating gas flowing at a high speed along the smooth surface 87 is increased, and the raw material solution can be more effectively thinned to make the raw material solution a mist of small fine particles.

  Furthermore, the nozzle 5 shown in FIG. 11 also injects the circulating gas from the outer periphery of the smooth surface 87. The circulating gas is injected from a circulating gas injection port 83 provided between the intermediate ring 92 and the outer ring 93. However, it is not always necessary to inject this reaction gas. This is because the raw material solution can be injected as fine particle mist with the circulating gas from the inner injection port without injecting the reaction gas from the outer injection port. The nozzle 5 that injects the circulating gas from both sides can collide the circulating gas at the edge 88 of the smooth surface 87 and more effectively chemically react the components contained in the raw material solution with the circulating gas. This is because the mist can be made into finer particles, and the raw material solution and the circulating gas can collide violently at the gas-liquid interface.

  In the nozzle 5 that injects two circulating gases and collides at the tip, the tip of the smooth surface 87 has a sharp edge 88. The intermediate ring 92 is provided with a smooth surface 87 at the tip surface, and the outer periphery of the tip is processed into a cylindrical shape, and an edge 88 is provided at the tip of the smooth surface 87. The intermediate ring 92 having this shape can form a sharp edge 88 (180 degrees−inclination angle α) at the tip of the smooth surface 87. However, although the nozzle is not shown, the outer periphery of the intermediate ring can be tapered to adjust the edge angle.

The nozzle 5 shown in FIG. 11 injects the raw material solution as a fine particle raw material solution in the following state.
(1) Supplying pressurized circulating gas to the injection path 94 provided between the center ring 90 and the inner ring 91 and the injection path 95 provided between the intermediate ring 92 and the outer ring 93, The raw material solution is sent out from the solution path 96 provided between the intermediate rings 92 to the smooth surface 87.
(2) The raw material solution supplied to the smooth surface 87 is thinly stretched by a circulating gas that flows at high speed along the smooth surface 87 to form a thin film flow.
For example, if the circulating gas is caused to flow along the smooth surface 87 at a flow rate of Mach 1.5 to feed the raw material solution into the solution path 96 and the flow rate at the tip of the thin film flow is 1/20 of the circulating gas, 30 5 m / s. If the diameter of the edge 88 provided at the tip of the smooth surface 87 is 50 mm, the raw material solution is supplied at 1 liter / min, and the film pressure of the thin film flow is 4 μm.

(3) The thin film flow of 4 μm is too thin after the edge 88 of the smooth surface 87 to be in a film state, and is broken into pieces by the surface tension to become fine particle mist.
(4) The fine particle mist collides with the circulating gas from both sides at the edge 88 and rubs and vibrates to make the mist even smaller.
(5) The mist of fine particles is conveyed radially by the circulating gas from both sides. This state is called a holocorn. The cone angle of the hollow cone is determined by the angle of the smooth surface 87, but can also be adjusted by the injection pressure of each circulating gas.

  Further, although not shown, the nozzle may be structured such that two different liquids are mixed to form fine particles of fine particles. In this nozzle, for example, the intermediate ring has a double tube structure of an inner intermediate ring and an outer intermediate ring, and a second liquid supply port can be provided between the inner intermediate ring and the outer intermediate ring. This nozzle can separate and collect fine particle powder formed by mixing two different liquids.

  In the above spray drying apparatus, the circulating gas discharged from the spray drying tower 1 is pressurized by the gas compressor 4 and supplied to the nozzle 5, and the raw material solution is atomized into the mist and sprayed by the nozzle 5. However, the spray drying apparatus of the present invention does not specify a mechanism for atomizing the raw material solution into a mist and spraying the nozzle and the gas compressor. As shown in FIG. 12, the spray drying apparatus arranges a sprayer 9 for atomizing the raw material solution into a mist in the spray drying tower 1, and the mist sprayed into the spray drying tower 1 by the sprayer 9. It can also be dried into fine particles in the spray drying tower 1.

  The spray drying apparatus shown in FIG. 12 has a sprayer 9 disposed at the upper part of the spray drying tower 1, and the raw material solution supplied from the solution tank 14 is atomized into mist by the sprayer 9. 1 is sprayed. As shown in FIG. 13, the sprayer 9 includes a rotating plate 36 that is rotated at a high speed by a motor 35 and a supply pipe 37 that supplies a fixed amount of raw material solution to the rotating plate 36. The sprayer 9 supplies a raw material solution from a ring-shaped supply pipe 37 to a rotating plate 36 that rotates at high speed, and crushes and diffuses the droplets of the raw material solution into fine mist by the centrifugal force of the rotating plate 36 that rotates at high speed. Spray. However, the sprayer is not specified as a structure in which the raw material solution is atomized into a mist with a rotating plate and sprayed. Any other structure capable of atomizing the raw material solution supplied from the solution tank into a mist and spraying can be used for the sprayer.

  The circulation type spray drying apparatus shown in FIG. 12 is a spray drying tower 1 that dries the raw material solution sprayed from the sprayer 9 into fine particles, and the circulating gas discharged from the spray drying tower 1 is supplied to the spray drying tower 1. A circulation path 8 for circulation is provided, and a circulation device 6 that is connected to the circulation path 8 and circulates the circulation gas in the circulation path 8. Further, in the spray drying apparatus of FIG. 12, the fine particle dried in the spray drying tower 1 is separated in the circulation path 8 from the circulating gas and recovered, and the fine particle is separated in the powder recovery device 2. A condenser 3 for cooling the circulating gas to liquefy and separate the solvent of the raw material solution and a heater 7 for heating the circulating gas from which the solvent has been separated by the condenser 3 are provided.

  In the circulation path 8, the circulating gas discharged from the spray drying tower 1 is passed through the powder collector 2, the condenser 3, and the heater 7 to be circulated through the spray drying tower 1. However, the spray drying apparatus does not necessarily need to arrange a heater in the circulation path. This is because a heater can be disposed in the spray drying tower 1. Further, the circulation path 8 shown in the figure is connected to the circulation side 6 for circulating the circulation gas to the circulation path 8 on the discharge side of the powder collector 2 and on the supply side of the condenser 3. In this spray drying apparatus, the circulating gas discharged from the spray drying tower 1 and circulated in the circulation path 8 is circulated to the spray drying tower 1 via the circulator 6. However, the circulator can also be placed on the discharge side of the condenser.

  As the circulator 6, one having the same structure as the above circulator can be used. That is, the circulator 6 can be a piston-type forced transfer machine 6A as shown in FIGS. 4 to 9, or a diaphragm-type forced transfer machine 6B as shown in FIG. it can.

DESCRIPTION OF SYMBOLS 1 ... Spray drying tower 2 ... Powder recovery device 3 ... Condenser 4 ... Gas compressor 4A ... Piston type forced transfer machine
4B ... Diaphragm type forced transfer machine 5 ... Nozzle 6 ... Circulator 6A ... Piston type forced transfer machine
6B ... Diaphragm type forced transfer machine 7 ... Heater 8 ... Circuit 8A ... Main circuit
8B ... First branch
8C ... Second branch 9 ... Sprayer 10 ... Chamber 10A ... Drying room
DESCRIPTION OF SYMBOLS 10B ... Recirculation | reflux chamber 11 ... Discharge port 12 ... Partition wall 12A ... Through-hole 14 ... Solution tank 15 ... Pump 16 ... Pressure adjustment mechanism 20 ... Cyclone 21 ... Exhaust port 22 ... Discharge port 23 ... Inlet port 24 ... Reciprocating motion mechanism 25 ... Drive mechanism 26 ... Cam 27 ... Elastic body 27A ... Coil spring 28 ... Stopper 30 ... Cooling heat exchanger 31 ... Heat exchange pipe 34 ... Reciprocating motion mechanism 35 ... Motor 36 ... Rotating plate 37 ... Supply pipe 38 ... Check valve 38A ... Valve 39 ... Path 40 ... Cylinder 40A ... Suction port
40B ... Exhaust port
40H ... closed end
40X… Top dead center chamber
40Y ... Bottom dead center chamber 41 ... Piston 41B ... Piston ring 42 ... Crank arm 42A ... Rotating shaft
42B ... Crank pin 43 ... Piston shaft 43A ... Tilt shaft 44 ... Check valve 44A ... Suction valve
44B ... Drain valve 45 ... Drive mechanism 46 ... Connecting rod 47 ... Blocking plate 47A ... Through hole 48 ... Seal 48A ... Oil seal
48B ... Pressure seal 49 ... Rotational speed adjustment mechanism 50 ... Cavity 50A ... Suction port
50B ... Exhaust port
50X ... cavity
50Y ... Cavity 51 ... Diaphragm 54 ... Check valve 54A ... Suction valve
54B ... Exhaust valve 55 ... Drive mechanism 56 ... Electromagnet 57 ... Control circuit 60 ... Linear motion mechanism 61 ... Guide rod 62 ... Slide base 63 ... Linear motion bearing 81 ... Injection port 82 ... Supply port 83 ... Injection port 87 ... Smooth surface 88 ... Edge 90 ... Center ring 91 ... Inner ring 92 ... Intermediate ring 93 ... Outer ring 94 ... Injection path 95 ... Injection path 96 ... Solution path 101 ... Spray drying tower 102 ... Cyclone 103 ... Condenser 105 ... Nozzle 106 ... Blower 107 ... Heater 201 ... spray drying tower 204 ... gas compressor 205 ... nozzle

Claims (14)

A spray-drying tower that dries the mist of the raw material solution sprayed from the nozzle through a pressurized circulating gas to form fine particles, and a powder recovery that separates and collects the fine particles dried in this spray-drying tower from the circulating gas And a condenser that cools the circulating gas from which fine particles have been separated by the powder recovery device to liquefy and separate the solvent of the raw material solution, and pressurizes and sprays the circulating gas from which the solvent has been separated by the condenser A gas compressor for supplying to the nozzle of the drying tower,
The gas compressor is a piston-type forced transfer machine that reciprocates the piston in the cylinder and pressurizes and transfers the circulating gas. The piston-type forced transfer machine extends in the reciprocating direction of the piston and moves the piston. A piston shaft that linearly moves in the reciprocating direction of the reciprocating motion, and a reciprocating motion mechanism that reciprocates the piston shaft,
Further, the opening on the reciprocating mechanism side of the cylinder is closed by a closing plate having a through hole through which the piston shaft passes slidably. The closing plate penetrates slidably. It has a seal that seals the surface of the piston shaft in a through hole with an airtight structure,
A circulation-type spray-drying apparatus, wherein the piston-type forced transfer machine is configured to pressurize a circulating gas and supply the pressurized gas to the nozzle to spray the raw material solution onto the mist from the nozzle. A spray-drying tower that dries the mist of the raw material solution sprayed from the nozzle through a pressurized circulating gas to form fine particles, and a powder recovery that separates and collects the fine particles dried in this spray-drying tower from the circulating gas And
A condenser that cools the circulating gas from which the fine particles have been separated by this powder recovery device to liquefy and separate the solvent of the raw material solution, and pressurizes the circulating gas from which the solvent has been separated by this condenser to A gas compressor to be supplied to the nozzle,
The gas compressor is a diaphragm type forced transfer machine, and this diaphragm type forced transfer machine pressurizes the circulating gas and supplies it to the nozzle so that the raw material solution is sprayed from the nozzle onto the mist. Spray drying equipment. A circulation path for circulating the circulation gas to the spray drying tower is provided. The circulation path is connected to a main circulation path for circulating the gas discharged from the spray drying tower and a discharge side of the main circulation path. The first branch path is connected to a gas compressor and the tip is connected to a nozzle, and the second branch path is connected to the spray drying tower without a nozzle. Consolidated
Furthermore, a circulating machine for circulating a circulating gas is connected to the main circulation path or the second branch path, and the circulating machine reciprocates a piston in a cylinder to circulate the circulating gas. This piston type forced transfer machine includes a piston shaft that extends in the reciprocating direction of the piston and linearly moves in the reciprocating direction of the piston, and a reciprocating mechanism that reciprocates the piston shaft. ,
Further, the opening on the reciprocating mechanism side of the cylinder is closed by a closing plate having a through hole through which the piston shaft passes slidably. The closing plate penetrates slidably. It has a seal that seals the surface of the piston shaft in a through hole with an airtight structure,
The circulating spray drying apparatus according to claim 1 or 2, wherein a circulating gas is circulated to the spray drying tower by a circulator of the piston type forced transfer device. A circulation path for circulating the circulation gas to the spray drying tower is provided. The circulation path is connected to a main circulation path for circulating the gas discharged from the spray drying tower and a discharge side of the main circulation path. The first branch path is connected to a gas compressor and the tip is connected to a nozzle, and the second branch path is connected to the spray drying tower without a nozzle. Consolidated
Further, the main circulation path or the second branch path is connected to a circulation machine for circulating a circulating gas, and this circulation machine is a diaphragm type forced transfer machine, and this diaphragm type forced transfer machine, The circulating spray drying apparatus according to claim 1 or 2, wherein circulating gas is circulated to the spray drying tower. A spray-drying tower that dries the mist of the raw material solution sprayed from the sprayer into fine particles, a powder recovery device that separates and recovers the fine particles dried in the spray-drying tower from the circulating gas, and this powder recovery device A condenser for cooling the circulating gas from which the fine particles have been separated to liquefy and separate the solvent of the raw material solution, and the circulating gas discharged from the spray drying tower through the powder recovery unit and the condenser for spraying. A circulation path that circulates in the drying tower, and a circulator that is connected to the circulation path and circulates the circulation gas in the circulation path,
The circulator is a piston-type forced transfer machine that circulates a circulating gas by reciprocating a piston in a cylinder, and the piston-type forced transfer machine extends in the reciprocating direction of the piston to reciprocate the piston. And a reciprocating mechanism for reciprocating the piston shaft.
Further, the opening on the reciprocating mechanism side of the cylinder is closed by a closing plate having a through hole through which the piston shaft passes slidably. The closing plate penetrates slidably. It has a seal that seals the surface of the piston shaft in a through hole with an airtight structure,
A circulation type spray drying apparatus configured to circulate a circulating gas to the spray drying tower with the piston type forced transfer machine. A spray-drying tower that dries the mist of the raw material solution sprayed from the sprayer into fine particles, a powder recovery device that separates and recovers the fine particles dried in the spray-drying tower from the circulating gas, and this powder recovery device A condenser for cooling the circulating gas from which the fine particles have been separated to liquefy and separate the solvent of the raw material solution, and the circulating gas discharged from the spray drying tower through the powder recovery unit and the condenser for spraying. A circulation path that circulates in the drying tower, and a circulator that is connected to the circulation path and circulates the circulation gas in the circulation path,
A circulation type spray drying apparatus in which the circulation machine is a diaphragm type forced transfer machine and the diaphragm type forced transfer machine circulates a circulating gas to the spray drying tower.   The reciprocating mechanism of the piston-type forced transfer machine includes a crank arm that reciprocates the piston shaft, a connecting rod that connects the crank arm to the piston shaft, and a drive mechanism that rotates the crank arm. Or the circulation type spray-drying apparatus described in any one of Claims 1, 3, and 5 provided with the cam which reciprocates the said piston, and the drive mechanism which rotates this cam.   The piston-type forced transfer machine divides the inside of the cylinder into a top dead center chamber pressurized by the piston and a bottom dead center chamber, and the top dead center chamber and the bottom dead center chamber The circulation type spray drying apparatus according to any one of claims 1, 3, and 5, wherein a connecting path is provided, and a check valve that is closed in a discharge stroke is provided in the path. The piston-type forced transfer machine is provided with an exhaust port on the closed plate side from the bottom dead center of the cylinder, and a suction port is provided on the closed end side with respect to the top dead center of the cylinder,
Alternatively, the circulation type spray drying according to claim 8, wherein an inlet is provided closer to the closing plate than the bottom dead center of the cylinder, and an exhaust outlet is provided closer to the closing end than the top dead center of the cylinder. apparatus.   The circulating type of the piston type forced transfer machine or the diaphragm type forced transfer machine includes a plurality of cylinders. Spray drying equipment.   The circulating spray dryer according to any one of claims 3 to 10, wherein the circulator is disposed on a supply side of the condenser.   The circulating spray drying apparatus according to any one of claims 1 to 11, wherein the circulating gas is any one of nitrogen, helium, argon, and carbon dioxide.   The circulation type spray drying apparatus according to claim 1, wherein the solvent of the raw material solution is alcohol.   The circulating spray drying apparatus according to any one of claims 1 to 13, wherein a linear motion mechanism that guides the piston shaft to linear motion is connected to the piston shaft.

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