JP7534762B2 - Freezing Granulation Equipment - Google Patents

Description

The present invention relates to a spray mechanism for a freeze granulation device, and more specifically, to a spray mechanism for a freeze granulation device that obtains frozen microparticles by spraying a sample liquid toward a low-temperature liquid.

The so-called spray freeze-drying granulation method is a known technique in which a suspension is sprayed into a low-temperature liquid in a pre-step to freeze the granules, and then the process proceeds to a freeze-drying step to obtain the granules (see, for example, Patent Document 1).

Japanese Patent Application Publication No. 1-293128

To obtain frozen microparticles, a low-temperature liquid is usually stored in a processing vessel, and the tip of the spray nozzle is held away from the liquid surface. In this state, a suspension of water or alcohol is sprayed from the spray nozzle to obtain frozen microparticles. However, while the suspension is being sprayed, the tip of the spray nozzle freezes and becomes blocked in a short time due to the rapid freezing using the low-temperature liquid, so the freeze granulation process can only be performed in very small batches. In addition, maintaining a constant distance between the liquid surface and the tip of the nozzle has a significant effect on the diameter and recovery rate of the microparticles, but when a commercially available product such as a muffed clamp is used to fix the spray nozzle, the nozzle position is difficult to determine, and the position of the spray nozzle must be adjusted manually, which lacks stability and quantitativeness, and a ruler is required separately to measure the spray distance, making it difficult to perform a stable freeze granulation process.

The present invention aims to provide a spray mechanism for a freeze granulation device that improves quantitative accuracy and reproducibility when producing frozen microparticles.

In order to achieve the above object, the freeze granulation apparatus of the present invention is a freeze granulation apparatus comprising a heat- insulating treatment vessel having an opening at the top, and a spray mechanism for spraying a sample liquid toward the liquid surface of a low-temperature liquid stored in the treatment vessel, the spray mechanism comprising a spray nozzle, a lid for covering the opening, a cylindrical metallic nozzle storage section which penetrates the lid in the vertical direction to communicate between the inside and the outside of the treatment vessel and which supports the spray nozzle by inserting therein, and a nozzle heating means which is embedded in the nozzle storage section and transfers heat to the spray nozzle, the lid has a nozzle support member for supporting the spray nozzle by inserting therein, and a nozzle heater for connecting the spray nozzle to the nozzle storage section. An operating means is provided for moving the nozzle storage section in a direction toward or away from the liquid surface of the cryogenic liquid, and the operating means comprises a rotating shaft having an operating knob on its upper end, a base member provided on the upper surface of the lid body and rotatably supporting the rotating shaft, and a guide member provided in the nozzle storage section and having an axial hole through which the rotating shaft passes, the axial hole being provided with a female threaded portion which screws into a male threaded portion provided on the rotating shaft to move the nozzle storage section up and down in accordance with the rotation of the operating knob, and the base member is provided with a scale indicating the amount of movement of the nozzle storage section .

According to the spray mechanism of the freeze granulation device of the present invention, the spray nozzle is inserted and supported by the nozzle storage section that penetrates the lid of the processing vessel, and further, the heat generated by the nozzle heating means embedded in the nozzle storage section is transferred to the spray nozzle, so that the tip of the spray nozzle can be kept at a temperature that does not freeze even during spraying, and frozen microparticles can be produced continuously. In addition, the nozzle storage section can be adjusted to a height position corresponding to the desired scale by simply turning the operating knob, due to the screw engagement between the rotating shaft and guide member that constitute the operating means. This makes it easy to maintain a constant spray distance from the liquid surface of the low-temperature liquid, thereby achieving stable freeze granulation processing.

FIG. 1 is a plan view of a freeze granulation apparatus showing an example of an application of a spray mechanism of the freeze granulation apparatus of the present invention. This is a cross-sectional view of FIG. FIG. 2 is a cross-sectional view taken along line III-III of FIG.

Figures 1 to 3 show an example of the application of the present invention to a freeze granulation device used to carry out the spray freeze drying granulation method. As shown in Figures 1 and 2, the freeze granulation device 11 includes a heat-insulating processing vessel 12 having an opening 12a at the top, a removable lid 13 that covers the opening 12a of the processing vessel 12, a cylindrical nozzle storage section 14 that vertically penetrates the lid 13 to communicate the inside and outside of the processing vessel 12, and a spray nozzle 15 that is inserted and supported in the nozzle storage section 14. The spray nozzle 15 sprays a sample liquid (suspension) toward the liquid surface L of the low-temperature liquid (e.g., liquid nitrogen) stored in the processing vessel 12.

The processing vessel 12 is a metal insulated vessel with an insulating layer formed between the outer vessel 12b and the inner vessel 12c, and the outer vessel 12b and the inner vessel 12c are integrally formed by welding the opening edges of each vessel. The lid 13 is a thick metal disk with a pair of handles 13a, 13a on both sides of the upper surface, and when the body 13b is fitted into the opening 12a of the processing vessel 12, the flange-shaped peripheral portion 13c is engaged with the upper end peripheral portion of the processing vessel 12 via a packing 16. The lid 13 also has a through hole 13d in the center that allows the nozzle storage portion 14 to slide, and an exhaust port 13e is provided at a position away from the through hole 13d.

The nozzle storage section 14 is a metallic cylinder long enough to store the nozzle body 17 of the spray nozzle 15, and a pair of electric heaters 18, 18 are embedded in both sides of the nozzle storage space S as nozzle heating means. The electric heater 18 is electrically connected to the power supply control section 19, and is arranged so that when energized, the heat generated by the heat generating section (energized heat generating resistive layer) is transferred to the nozzle body 17 via the nozzle storage section 14.

The spray nozzle 15 atomizes and sprays the sample liquid by continuously supplying two fluids, the sample liquid and pressurized air, and specifically comprises the nozzle body 17 with a nozzle hole 17a at the lower end and a piping connection part 20 connected to the upper end of the nozzle body 17. In addition, when the nozzle body 17 is inserted into the nozzle storage space S and the piping connection part 20 is in a storage position abutting the upper end 14a of the nozzle storage part 14, the nozzle hole 17a is held in an inner position slightly retracted from the lower end 14b of the nozzle storage part 14. As a result, the pressurized sample liquid and air are mixed in the pipeline of the piping connection part 20, and then sprayed from the nozzle hole 17a through the nozzle body 17.

The freeze granulation device 11 is provided with an operating means 21 in a spray mechanism that combines a lid body 13, a nozzle storage section 14, and a spray nozzle 15, and by operating the operating means 21, the nozzle storage section 14 and the spray nozzle 15 can be moved up and down integrally with respect to the lid body 13.

3, the operating means 21 includes a rotating shaft 23 with an operating knob 22 at its upper end, a base member 24 that rotatably supports the rotating shaft 23, and a guide member 25 having an axial hole through which the rotating shaft 23 passes. The base member 24 is a roughly U-shaped member consisting of a support 26 with a scale 26a indicating the amount of vertical movement of the nozzle storage section 14 and a pair of upper and lower bearing members 27, 28, and is provided on the upper surface of the cover 13 and in the vicinity of the through hole 13d. The guide member 25 is a plate piece provided on the outer periphery of the upper end of the nozzle storage section 14, and is engaged and held between the two bearing members 27, 28 with the rotating shaft 23 passing through the axial hole.

The rotating shaft 23 is provided with a male threaded portion 23a of a length equivalent to the span between the two bearing members 27, 28, and functions as a grip bolt (thumb screw) integral with the operating knob 22. Meanwhile, the shaft hole of the guide member 25 is provided with a female threaded portion 25a that screws into the male threaded portion 23a. As a result, when the operating knob 22 is rotated, the rotational motion of the rotating shaft 23 is converted into linear motion of the guide member 25 by the meshing of the threaded portions 23a, 25a. That is, the nozzle storage portion 14 moves vertically relative to the lid 13, and accordingly, the spray nozzle 15 moves in a direction approaching or receding from the liquid surface L of the cryogenic liquid while maintaining the storage position.

To carry out the spray freeze-drying granulation method using the freeze granulation apparatus 11 thus constructed, frozen microparticles are produced in a process prior to the drying process. First, a preset amount of low-temperature liquid is stored in the processing vessel 12 based on the type of sample liquid and the processing amount. One method for stirring the low-temperature liquid is to use a magnetic stirrer as a mounting base for the processing vessel 12, and to stir the low-temperature liquid by rotating a stirrer inserted in the processing vessel 12 using magnetic force.

Next, for the spray nozzle 15, the corresponding hoses (not shown) are connected to the sample liquid hose joint 20a and the air hose joint 20b of the piping connection part 20, respectively, and then the nozzle body 17 is inserted into the nozzle storage part 14, and in this provisionally assembled state, the lid body 13 is placed over the opening 12a of the processing vessel 12. This seals the opening 12a and keeps the internal area of the inner tank 12c under an extremely low temperature atmosphere. Now, by rotating the operating knob 22, for example, the guide member 25, which is at its upper limit position, is lowered to the desired position of the scale 26a. As a result, the spray distance at the initial operation, i.e., the distance between the liquid surface L of the low-temperature liquid and the nozzle hole 17a of the spray nozzle 15, is kept constant, and processing is possible.

When the sample liquid is sprayed from the nozzle hole 17a and the electric heater 18 is energized at the same time, the nozzle storage section 14, which is a thermal conductor, quickly transfers the heat generated by the electric heater 18 to the nozzle body 17. This heats the tip of the nozzle body 17, including the nozzle hole 17a, and the temperature is maintained at 0°C or higher, that is, at a temperature at which the nozzle hole 17a does not freeze and become blocked. Meanwhile, the sprayed fine particles are instantly frozen by the cold air of the low-temperature liquid, and are deposited as frozen fine particles at the bottom of the processing vessel 12. At this time, the power supply control section 19 sets off a timer at a set time, for example, when the low-temperature liquid has completely evaporated, and ends the energization of the electric heater 18. In this way, the temperature rise inside the processing vessel 12 is suppressed.

In this way, according to the spray mechanism of the freeze granulation device 11, the spray nozzle 15 is inserted and supported by the nozzle storage section 14 that penetrates the lid 13 of the processing container 12, and further, the heat generated by the electric heater 18 embedded in the nozzle storage section 14 is transferred to the spray nozzle 15. Therefore, even during spraying, it is possible to maintain the tip of the spray nozzle 15 at a temperature that does not freeze, and frozen fine particles can be continuously produced. In addition, by screwing the rotating shaft 23 and the guide member 25 that constitute the operating means 21 together, the nozzle storage section 14 can be adjusted to a height position corresponding to the desired scale 26a by simply turning the operating knob 22. This makes it easy to keep the spray distance of the spray nozzle 15 constant from the liquid surface L of the low-temperature liquid, thereby achieving stable freeze granulation processing.

The present invention is not limited to the above-mentioned embodiment, and the nozzle heating means is not particularly limited as long as it is a heater capable of heating the nozzle body, but from the viewpoint of manufacturing costs, it is preferable that it is an electric heater. In addition, the operating means has an advantage of being able to stably raise and lower the nozzle storage section by adopting a screw meshing structure, but it is sufficient to hold the guide member on the lid body, and various structures can be adopted, such as a structure in which blocks are stacked to hold the guide member at a desired height. Furthermore, adjustment by the operating means can be performed at any time, and can also be adjusted before attachment to the lid body. In addition, each material can be appropriately selected taking into consideration heat transfer, insulation, strength, moldability, etc., and is not particularly limited.

11...freeze granulation device, 12...processing container, 12a...opening, 12b...outer tank, 12c...inner tank, 13...lid, 13a...handle, 13b...body, 13c...periphery, 13d...through hole, 13e...exhaust port, 14...nozzle storage section, 14a...upper end, 14b...lower end, 15...spray nozzle, 16...packing, 17...nozzle body, 17a...nozzle hole, 18...electric heater, 19...power supply control section, 20...piping connection section, 20a...sample liquid hose joint, 20b...air hose joint, 21...operation means, 22...operation knob, 23...rotating shaft, 23a...male threaded section, 24...base member, 25...guide member, 25a...female threaded section, 26...support, 26a...scale, 27, 28...bearing member

Claims (1)

A freeze granulation apparatus comprising a heat-insulating treatment vessel having an opening at the top and a spray mechanism for spraying a sample liquid toward a liquid surface of a low-temperature liquid stored in the treatment vessel,
The spray mechanism includes:
A spray nozzle;
A cover for covering the opening;
a cylindrical metal nozzle storage section that passes through the lid in the vertical direction to communicate between the inside and the outside of the treatment vessel and that supports the spray nozzle therein;
a nozzle heating means embedded in the nozzle housing portion to transfer heat to the spray nozzle;
the cover is provided with an operating means for moving the spray nozzle inserted and supported by the nozzle storage portion in a direction toward or away from a liquid surface of the cryogenic liquid ,
the operating means includes a rotating shaft having an operating knob at an upper end thereof, a base member provided on an upper surface of the lid body and rotatably supporting the rotating shaft, and a guide member provided in the nozzle storage section and having an axial hole through which the rotating shaft passes;
The freeze granulation apparatus is characterized in that the axial hole is provided with a female thread portion which screws into a male thread portion provided on the rotating shaft to move the nozzle storage portion up and down in accordance with the rotation operation of the operating knob, and the base member is provided with a scale which indicates the amount of movement of the nozzle storage portion .

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