JPS62196575A - Frozen-grain production unit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is an apparatus for producing frozen particles such as fine ice particles that are suitably used as abrasive grains, polishing materials, etc. for ice blasting. , in particular, by spraying and dripping the liquid to be frozen onto the refrigerant liquid surface from a spray nozzle provided at the upper part of the refrigerant storage container, heat exchange is performed with the refrigerant to produce fine frozen particles. This is a 1:1 improvement to manufacturing equipment.

(Prior art) In general, in this type of frozen particle production apparatus, the liquid to be frozen is sprayed from a spray nozzle toward the refrigerant liquid surface while being diffused in a substantially conical shape, so that the fine particles of the sprayed liquid to be frozen are It is inevitable that some of the refrigerant will not reach the refrigerant liquid level and will collide with and adhere to the inner wall surface of the frozen granule manufacturing container, and will be frozen as it is. The frozen matter that adheres to the inner wall grows large in a relatively short time by continuously spraying the liquid to be frozen, so the effective production area of frozen particles, that is, the liquid to be frozen is sprayed and dropped This results in a significant reduction in the effective area on the liquid surface of the refrigerant, resulting in a significant decrease in the production efficiency of frozen particles. Because it will be used for ice blasting etc. along with the original fine frozen particles,
This also causes inconvenience in precision ice blasting, etc., which requires the use of frozen particles of fine and uniform particle size.

Conventionally, the solution to this problem was to periodically stop the operation of the equipment and remove the inside of the frozen grain manufacturing container. Either remove the frozen matter adhering to the surface (hereinafter referred to as the "first solution"), or make the spray angle of the spray nozzle smaller than usual, so that the spray area is in contact with the largest area in plan view, that is, the refrigerant liquid surface. The area of the refrigerant liquid surface should be smaller than the total area of the refrigerant liquid surface to a certain extent to prevent the sprayed particles of the liquid to be frozen from scattering in the direction of colliding with the inner wall surface of the container (hereinafter referred to as "No. (hereinafter referred to as the "Third Solution"), or by causing a refrigerant to flow down along the inner wall surface of the frozen grain production container to prevent the generation of frozen matter on the inner wall surface (hereinafter referred to as the "Third Solution"). 0 (Problem to be solved by the invention) However, with the first solution, the continuous operation time of the device is inevitably shortened, which not only reduces the production efficiency of frozen particles but also causes loss of refrigerant. The disadvantage was that the rate was high.

In addition, in the second solution, the effective production area for frozen grains has to be made considerably smaller, and it is natural to feel that the production area for frozen grains is very small compared to the diameter and volume of the container. Although it is possible to lengthen the continuous operation time, it cannot be a method with good equipment efficiency.

In the third solution, the refrigerant flowing down the inner wall of the container is
Since it adds to the refrigerant sprayed from the nozzle and provides the cooling energy necessary for freezing as a whole, the amount of refrigerant introduced from each path must be controlled by making subtle adjustments. In practice, it is extremely difficult to effectively prevent the formation of frozen matter on the inner wall surface of a container using a limited amount of flowing refrigerant, and this is far from being an effective solution.

The present invention has been made as a result of intensive research to solve this problem by paying attention to the above-mentioned situation. It is an object of the present invention to provide a frozen granule manufacturing apparatus that can be operated continuously over a period of 20 to 30 minutes, thereby significantly improving the production efficiency of frozen granules and the efficiency of the apparatus.

(Means for Solving the Problems) The frozen grain production apparatus of the present invention has the following features:
In particular, gas injection holes are arranged in the refrigerant storage container so as to form a gas curtain surrounding the area where the liquid to be frozen is sprayed by the injection nozzle.

On the right, a gas curtain is a curtain (
This means forming a curtain in the form of a curtain, and the air in the so-called air curtain is expanded into gas in general for use.

(Function) According to this configuration, even if some of the sprayed particles of the liquid to be frozen are scattered toward the inner wall surface of the refrigerant storage container, the collision of the scattered particles with the inner wall surface of the container prevents the gas from flowing through the gas injection holes. This is reliably blocked by the gas curtain formed by the sprayed particles, and it is possible to prevent the trouble of the sprayed fine particles adhering to the inner wall surface of the container and freezing.

(Example) Hereinafter, the configuration of the present invention will be explained in more detail based on the example shown in FIGS. 1 and 2.

The frozen granule production apparatus shown in FIG. 1 includes a refrigerant storage container 1 having a rectangular cross section, which stores a predetermined amount of refrigerant 2 such as liquefied nitrogen, and a spray nozzle 3 disposed in the upper part of the container. .

The spray nozzle 3 has a mixer 4 in the center as shown in FIG.
A spray passage 5 is formed inside, and a spray passage 6 is formed on the outer periphery, and a spray lower which is connected to the spray passage 5 is opened on the lower surface, and which is connected to the injection passage 6 and surrounds the spray lower. An annular injection port 8 is provided. A supply pipe 9 for supplying a liquid to be frozen such as water or Freon liquid is connected to the spray passage 5, and an introduction pipe 9 for introducing a pressurized gas such as nitrogen gas or air pressurized to a predetermined pressure is connected to the spray passage 6. tube lO
Connect it. Although not shown, the injection passage 6 communicates with the mixer 4 via a known pressure reducing valve. Both the spray lower and the injection port 8 are formed in the shape of a truncated cone that expands downward, and both of them have the same downward expansion angle of 7°8.

Therefore, if this spray nozzle 3 is used, when the liquid to be frozen is supplied from the supply pipe 9 to the spray passage 5 and the pressurized gas is introduced from the introduction pipe 10 to the injection passage 6, the liquid to be frozen is It is mixed with a part of the pressurized gas (hereinafter referred to as "atomizing gas") introduced from the injection passage 5 via the pressure reducing valve, and then subjected to the action of this atomizing gas, is sprayed from the spray lower in the form of fine particles. Then, spray fine particles 12 a of the liquid to be frozen diffuse from the spray lower in a substantially conical shape and reach the refrigerant liquid surface 2 a.
Another part of the pressurized gas (hereinafter referred to as "gas curtain forming gas") is injected from the injection port 8 through the injection passage 6 to form the spray area 12. A substantially conical ring-shaped gas curtain 13 is formed which surrounds the entire surface in the vertical direction.

Incidentally, the lower angle of the spray lower, that is, the spray angle α is set so that the lower end of the spray region 12 can cover almost the entire surface of the refrigerant liquid surface 2a, that is, the effective production area of frozen particles is as large as possible. It is also desirable to set the aperture diameter of the spray lower according to the required particle size of the sprayed fine particles 12a, that is, the particle size of the frozen particles.

For example, the cross-sectional area of the refrigerant storage container 1, that is, the refrigerant liquid surface 2a
dimensions are 450 WMX 450 theory, the distance between the spray lower and the refrigerant liquid level 2a is within 700 mm, the required particle size of frozen particles is 50 to 100 μ, and the spray nozzle pressure is 21 (9/d).
G, the spray angle α of the spray lower is 30°
It is desirable to set the opening diameter to about 0.2 m.

Further, the atomized fine particles 12 a... by the gas curtain 13
In order to effectively exhibit the effect of preventing adhesion to the inner wall surface 1a of the container, the gas injection pressure from the injection port 8 must be at least 0.2 to 0.5 h/lower than the liquid spray pressure from the spray lower.
- It is desirable to set it to a certain degree.

Such a setting can be made by adjusting the pressure reducing valve when the pressurized gas introduced from the introduction pipe 10 is used both as the atomizing gas and the gas curtain forming gas as in this embodiment, and the atomizing gas and the gas curtain forming gas can be When the curtain forming gas and the curtain forming gas are introduced from different sources, the gas pressures may be adjusted separately.

However, the pressure of the gas curtain forming gas is
In terms of the consumption amount, it is not preferable to increase the amount more than necessary, and there is no need to do so.

In the above embodiment, the spray nozzle 3 has a special structure as shown in FIG. 2, and is formed into a substantially conical ring shape so that the gas curtain 13 completely surrounds the spray area 12 (up and down). However, the atomized fine particles 12
The adhesion of a... to the inner wall surface 1a of the container is due to the fact that the spray area 12 has a substantially conical shape that expands downward, so that the refrigerant liquid level 2
Taking into consideration the fact that particles are particularly likely to be generated in the vicinity of a, the atomized fine particles 12 a...
By forming it so as to surround only the N location, that is, the lower end portion of the spray area 12, the effect of preventing the spray particles 12a from attaching can be sufficiently effectively exhibited. can.

Therefore, for example, as understood from the longitudinal cross-sectional view shown in FIG. 3 and the cross-sectional view shown in FIG.
A rectangular annular gas injection pipe 14 attached to the inner wall surface 1a of the container is fixedly installed near the upper part of the gas injection pipe 14, and pressure is applied from a large number of injection holes 14a formed on the lower surface of the gas injection pipe 14. By injecting gas, it may be configured to form a gas curtain 13 that surrounds the lower part of the spray area 12 in the vertical direction. In this case, injection hole 1.4
The injection pressure from a... does not need to be higher than necessary as in the previous embodiment, but usually],, OKg
If it is about /d or more, there is no problem and it is within a desirable range. In addition, in FIG. 3, 3 is a usual spray nozzle, and 15 is a pressurized gas introduction pipe connected to the ejection pipe 14.

(Effects of the Invention) When operating the frozen particle manufacturing apparatus of the present invention, since the area where the liquid to be frozen is sprayed by the spray nozzle is surrounded by a gas curtain formed by gas injection, the sprayed fine particles of the liquid to be frozen are directed to the inner wall surface of the container. The adhesion of frozen substances to the inner wall surface of the container can be virtually completely avoided.

Therefore, if the frozen granule manufacturing apparatus of the present invention is used, the continuous operation time can be extended indefinitely, and together with the fact that there is no need to make the spray angle of the spray nozzle smaller than necessary, the production efficiency of frozen granules can be improved. can be significantly improved, and equipment efficiency can also be improved. Furthermore, since there is virtually no need to perform the work of removing frozen matter adhering to the inner wall surface of the container, there is no loss of refrigerant associated with this work, which is extremely advantageous economically.

In addition, since frozen particles attached to the inner wall of the container do not fall into the refrigerant, the uniformity of frozen particles recovered from the refrigerant can be maintained, which can be used even when ice blasting, etc., which requires particularly high precision is required. No problems 0 The device of the present invention is effective when applied to a wide range of general frozen grain manufacturing equipment, but especially when applied to the fine frozen grain manufacturing equipment described in Japanese Patent Application No. 60-258496. , is extremely effective in producing uniform micro-frozen grains.

[Brief explanation of drawings]

FIG. 1 is a schematic longitudinal sectional side view showing an embodiment of the frozen granule manufacturing apparatus according to the present invention, FIG. 2 is an enlarged longitudinal sectional side view of the same essential parts, and FIG. FIG. 4 is an enlarged sectional view taken along the TV--TV line in FIG. 3. 1... Refrigerant storage container, 1a Container inner wall surface, 2 Refrigerant, 2
a... Refrigerant liquid level, 3.3'... Spray nozzle 8.14a
Gas injection hole, 12. Spray area, 12a. Spray fine particles, 13. Gas curtain.

Claims (1)

[Claims] By spraying and dripping the liquid to be frozen onto the refrigerant liquid surface from a spray nozzle installed at the top of the refrigerant storage container,
In the frozen particle production apparatus configured to produce fine frozen particles, gas injection holes are arranged in the refrigerant storage container so as to form a gas curtain surrounding the spray area of the liquid to be frozen by the spray nozzle. Features of frozen grain production equipment.