JP2011167822A - Injection nozzle for dry ice snow washing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide improved generating efficiency and washing efficiency of dry ice snow used for a dry ice snow washing device. <P>SOLUTION: A mixture chamber 22 for mixing the dry ice snow W and compressed air Y is provided in the inside, and a nozzle body 21 is formed by respectively communicating an ice supply passage 23, an air supply passage 24, and an injection passage 25 with the mixture chamber. On the ice supply passage 23 side of the nozzle body 21, a generating tube 28 in which the dry ice snow W is generated by injecting liquefied carbon dioxide X, and an orifice tube 30 having an injection hole 31 through which the liquefied carbon dioxide X is injected into the generating tube and a plurality of gas holes 32 provided on the injection hole periphery having the same axial center are continuously provided. An acceleration tube 35 that synchronously injects the dry ice snow W and the compressed air Y that are mixed in the mixture chamber 22 of the nozzle body 21 from a discharge port 38 is attached to the injection passage 25 side of the nozzle body 21. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an improvement in an injection nozzle that efficiently generates and injects dry ice snow in a cleaning apparatus that uses dry ice snow and compressed air.

  Conventionally, a cleaning device using dry ice is cleaned using a cleaning device that pulverizes and pelletizes dry ice that has been solidified in advance, and dry ice snow in which liquefied carbon dioxide is formed into powder. Devices are known. Dry ice has the property of not sublimating at the same time as it collides with the object to be cleaned, so it is difficult to damage the object to be cleaned, and dry ice is non-toxic and non-flammable. Since it is difficult to cause damage due to wear or the like, it is widely used for cleaning electronic parts and OA equipment, removing deposits from a film forming apparatus, and the like.

JP 2009-248236 A JP 2001-259555 A

  The dry ice cleaning apparatus for pulverizing and cleaning the dry ice uses solidified dry ice, so it cannot be washed for a long time, and has a personnel for supplying dry ice. Since it is necessary, there is a problem that work efficiency is poor.

  The latter type of cleaning apparatus using dry ice snow is very uneconomical because of its low generation efficiency because dry ice snow has very fine particles and is likely to sublime when exposed to heat. Therefore, liquefied carbon dioxide and compressed air, which is an injection material, are provided in separate circuits, and both are mixed in the vicinity of the injection nozzle, gasified, and injected to improve production efficiency.

  However, the dry ice snow cleaning device has a distance to pump the dry ice snow generated by adiabatic expansion of the fed liquefied carbon dioxide to the injection nozzle. Since it evaporates, the cleaning efficiency is poor, a lot of liquefied carbon dioxide must be used, and there are many problems such as high cost and uneconomical.

  The present invention produces small and hard dry ice snow in an injection nozzle to improve the production efficiency of dry ice, thereby reducing the amount of liquefied carbon dioxide used and improving the economic effect. The purpose is to increase the cleaning effect by spraying ice snow onto the object to be cleaned.

   In order to solve the above problems, the present invention is provided with a mixing chamber 22 for mixing dry ice snow W and compressed air Y therein, and a supply path 23, an air supply path 24, and an injection path 25 are communicated with the mixing chamber. A production pipe 28 for injecting liquefied carbon dioxide X into the pipe to generate dry ice snow W is attached to the supply passage 23 of the nozzle body 21 formed in this way, and the liquefied carbon dioxide in the central axis direction is upstream of the production pipe. An injection hole 31 for injecting X is provided, an orifice pipe 30 provided with a plurality of gas holes 32 on the same circumference at the periphery of the injection hole is connected, and the dry ice is provided on the injection path 25 side of the nozzle body 21. An air hose 16 in which an acceleration pipe 35 provided with an injection port 38 for simultaneously injecting snow W and compressed air Y is connected, and one end of the nozzle body 21 is connected to the compressor 15 is connected to the air supply path 24 of the nozzle body 21. Ligated, characterized by comprising connecting the other end of the hose 13 on the upstream side was connected at one end to the liquefied carbon dioxide container 12 X was housed in the orifice tube 30. Further, the inner diameter D of the generation tube 28 is 1.0 to 30.0 mm, and the length L of the generation tube is 15 to 500 mm. Further, the orifice pipe 30 is provided with an injection hole 31 for injecting the liquefied carbon dioxide X into the generation pipe 28 in the direction of the central axis, and a plurality of gas holes are formed on the same circumference at the periphery of the injection hole. It is characterized by being arranged in a heavy or double ring shape. Furthermore, the inner diameter d of the injection hole 31 provided at the center of the orifice pipe 30 is 0.1 to 1.5 mm, and the inner diameters of the plurality of gas holes 32 provided at the periphery of the injection hole are each about 0.1 mm. It is formed to be 1 to 0.3 mm.

  As described above, the spray nozzle 20 according to the present invention sprays the liquefied carbon dioxide X from the gas hole 32 of the orifice pipe 30 into the production pipe 28 to form the diffusion suppression cylindrical film portion S, and the inside of the diffusion suppression cylindrical film portion. Similarly, by injecting the liquefied gas X from the injection hole 31 of the orifice pipe 30, it is possible to efficiently generate small and hard dry ice snow, so that the amount of liquefied carbon dioxide used can be reduced, which is very economical. Further, the dry ice snow W is mixed with the compressed air Y in the mixing chamber 21 of the nozzle body 21 and accelerated by the accelerating pipe 35 and sprayed from the injection port 38 onto the object to be cleaned, thereby causing a thermal shock on the surface of the object to be cleaned. Therefore, it is possible to efficiently clean with the expansion energy when dry ice snow enters into the crack, so that the cleaning cost can be suppressed and it is economical.

It is the schematic which shows one Example of the dry ice snow washing | cleaning apparatus of this invention. It is a principal part expanded sectional view of an injection nozzle. It is the principal part expanded sectional view of the orifice pipe | tube which produces | generates dry ice snow, and a production | generation pipe | tube. FIG. 4 is a cross-sectional view taken along line AA in FIG. 3. It is a characteristic diagram which shows the relationship between the cross-sectional area D / d of an orifice pipe and a production | generation pipe | tube, and the length L of a production | generation pipe | tube. It is a principal part expanded sectional view of the orifice pipe | tube and production | generation pipe | tube which comprise the conventional injection nozzle. FIG. 7 is a sectional view taken along line BB in FIG. 6.

  FIG. 1 is a schematic view showing an example of a dry ice snow cleaning apparatus, FIG. 2 is an enlarged sectional view of a main part of an injection nozzle, and FIG. 3 generates dry ice snow. FIG. 4 is an AA line cross-sectional view of FIG. The cleaning device 10 is provided with a liquefied carbon dioxide X (hereinafter referred to as liquefied gas) fed from a container 12 containing liquefied carbon dioxide in the mixing chamber 22 provided in the nozzle body 21 on the rear side of the nozzle body 21. The dry ice snow W is generated by being injected into the generating pipe 28, and the dry ice snow and the compressed air Y sent from the compressor 15 are mixed in the nozzle body 21 and provided on the front side of the nozzle body. In addition, cleaning is performed for dirt such as a film sprayed from the injection port 38 provided at the tip of the acceleration tube 35 and adhered to the surface of the object to be cleaned.

  The container 12 stores liquefied carbon dioxide X pressurized to 2.0 MPa. The liquefied gas is fed to the injection nozzle 20 through the gas hose 13, and an open / close valve is provided in the middle of the gas hose 13. 14 is attached. On the other hand, the compressed air Y is pressurized to about 0.6 to 0.8 MPa by the compressor 15, and the other end of the air hose 16 having one end connected to the compressor 15 is connected to the injection nozzle 20. An open / close valve 17 is attached.

  As shown in FIGS. 2 and 3, a mixing chamber 22 in which dry ice snow W and compressed air Y are mixed is provided in the center of the nozzle body 21 located at an intermediate portion of the injection nozzle 20. A rear-side supply path 23 communicating with the chamber and a front-side injection path 25 are formed in a straight line, and the air supply path 24 is positioned between the two to form a T-shape. It is. The air supply path 24 communicated with the mixing chamber 22 may be formed at an acute angle of more than 90 degrees with respect to the injection direction on the tip end side of the injection nozzle 20.

  The nozzle body 21 has a generation pipe 28 that adiabatically expands the liquefied gas X to generate dry ice snow W on the supply path 23 provided on the rear side that is one side of the mixing chamber 22, and generates the liquefied gas X. An orifice tube 30 to be injected into the tube 28 is connected, and the surface is cleaned by simultaneously spraying dry ice snow W and compressed air Y to the injection path 25 side located on the front side of the mixing chamber 22. For this purpose, an acceleration tube 35 is attached.

  As shown in FIGS. 2 and 3, the generating pipe 28 is screwed or fixedly connected to the ice supply path 23 located on the rear side of the nozzle body 21 and has a circular inner diameter. The inner diameter D and the length L of the generation pipe 28 are formed in a relative relationship with the inner diameter d of the injection hole 31 provided in the orifice pipe 30 connected to the upstream side of the generation pipe.

  As shown in FIGS. 3 and 4, the orifice pipe 30 is connected to the rear side of the generation pipe 28, and connects the front end of the gas hose 13 having the rear end connected to the container 12 storing the liquefied gas X on the upstream side. It is. An injection hole 31 for injecting the liquefied gas X into the production pipe 28 in the central axis direction of the orifice pipe 30 and a plurality of, preferably eight gas holes 32 on the same circumference at the periphery of the injection hole. Are arranged in a ring shape at equal intervals. When the liquefied gas X is injected into the production pipe 28 from each gas hole 32, a cylindrical gas film (hereinafter referred to as a diffusion suppressing cylinder film portion) S is formed in the downstream direction of the inner peripheral surface of the production pipe 28. .

  The inner diameter of the injection hole 31 provided at the center of the orifice pipe 30 is 0.1 to 1.5 mm, and the inner diameter of each gas hole 32 provided annularly around the injection hole 31 is 0.1 to 1.5 mm. When 0.3 mm, the inner diameter of the production tube 28 is 1.0 to 30.0 mm, and the length is formed in the range of 15 to 500 mm.

The above relationship shows the range in which dry ice snow W (0.2 to 0.5 mm) having a small particle size and hard as shown in FIG. Assuming that the inner diameter of the generating tube 28 is D and the inner diameter of the injection hole 31 is d, the injection hole so that the cross-sectional area of the inner diameter / the total cross-sectional area ratio of the injection holes, D ² / d ² is in the range of 25 to 35 It is preferable to set the inner diameter of d.

  This is because if the inner diameter D of the production tube 28 is too large compared to the inner diameter d of the injection hole 31, the liquefied gas is excessively expanded and the rate of vaporization increases. To do. On the other hand, if the inner diameter D is too small, the liquefied gas is injected in a liquid state due to insufficient expansion, and clogging is likely to occur.

For example, if the inner diameter D of the production tube 28 is 2 mm and D ² / d ² is set to 30%, which is the above-mentioned central value, D ² / d ² = 30, so d ² = D ² / 30, d = D ² / √30 = ² / √30≈2 / 5, 5≈0.36, that is, the inner diameter d of the injection hole 31 is suitably 0.36 mm.

Conversely, the inner diameter d of the injection hole 31 can be determined to determine the inner diameter D of the production tube 28 (however, D ² / d ² has a width of 25 to 35, and the lower limit and the upper limit thereof are both about 5). Is allowed).

Characteristic diagram shown in FIG. 5, the an illustration of the relationship of ^{D 2 / d 2, D 2} / d 2 on the vertical ^axis, when the variable d taking D on the horizontal axis, the injection hole 31 The inner diameter d and the inner diameter D of the production tube 28 are obtained. For any inner diameter D, d can be easily determined so that D ² / d ² is in the range of 25 to 35.

  Therefore, when the relationship between the inner diameter d of the injection hole 31 and the inner diameter of the generating tube 28 is determined from FIG. 5 as described above, if D is set to 2 mm, the large diameter is too large when d is 0.5 mm. It can be seen that 0.3 mm is too small.

  On the other hand, the length L of the production tube 28 is 15 to 500 mm, preferably 20 to 200 mm, as described above. If this length is less than the lower limit value, the liquefied gas X is suddenly released into the atmosphere. Thus, the necessary pressure by the production tube 28 is not applied, and the produced dry ice does not become hard. Moreover, the jetted gas is scattered and the directionality is not determined. On the other hand, if the upper limit is exceeded, the production tube 28 is too long and is not practical and is likely to be clogged in the tube.

  As shown in FIG. 2, the accelerating tube 35 is connected to the downstream side of the injection passage 25 of the nozzle body 21 by screwing or fixing, and the rear portion of the internal passage 36 is provided with a taper-shaped diameter expansion at the tip side. The narrow diameter portion 37 is provided on the side to accelerate the flow velocity, and the dry ice snow W and the compressed air Y can be mixed and injected from the injection port 38 provided at the tip of the acceleration tube.

  Hereinafter, the operation of the embodiment of the dry ice snow cleaning device 10 of the present invention will be described. The liquefied gas X is sent from the container 12 to the orifice pipe 30 through the gas on-off valve 14 attached to the gas hose 13 at a pressure of about 2 MPa. Liquid is injected from the injection hole 31 of the orifice pipe 30 into the production pipe 28, and adiabatic expansion occurs in the production pipe to generate dry ice snow W.

  As shown in FIG. 3, the liquefied gas X fed from the container 12 is injected into the production pipe 28 from the injection hole 31 of the orifice pipe 30, and is concentrically surrounded with the injection hole 31 in the production pipe. The liquefied gas X is also ejected from the plurality of gas holes 32 provided in a double manner, and a diffusion suppression cylindrical film portion S is formed on the inner peripheral surface of the generation tube 28 in the downstream direction.

  Since the inside of the diffusion suppression cylindrical film portion S formed in the generation pipe 28 is formed in a low temperature atmosphere of −78 ° C., the liquefied gas X injected from the injection holes 31 in the low temperature atmosphere does not vaporize. As it passes through the triple point as it is, it can be crystallized to produce 0.2 to 0.5 mm dry ice snow W that is small and hard.

  When the small and hard dry ice snow W is mixed with the compressed air Y in the mixing chamber 22 of the nozzle body 21, the sublimation loss that the dry ice snow vaporizes due to the heat of the compressed air can be reduced. It is possible to improve the mixing ratio of the dry ice snow W that is sprayed from the injection port 38 to the object to be cleaned. Therefore, it is easy to generate micro cracks due to thermal shock on the surface of the object to be cleaned, and dry ice snow can penetrate into the generated cracks and can be efficiently cleaned with expansion energy.

  The orifice tube 30 gasifies the liquefied gas X injected from the peripheral gas hole 32 by making the inner injection holes 31 and the peripheral gas holes 32 have different inner diameters and different injection pressures, thereby causing a diffusion suppression cylinder film. The portion S is formed, and the liquefied gas X is injected into the diffusion suppression cylindrical membrane portion S from the injection hole 31 so that the dry ice snow W can be efficiently formed.

  If the particle size is too small, the dry ice snow W has a high sublimation rate and the generation efficiency of the dry ice snow is poor. Also, if the hardness is insufficient, the dry ice snow W is sublimated by external heat (compressed air), resulting in a large loss. It is bad and uneconomical. Moreover, if the particle size is too large, dry ice snow will not easily enter the gaps between the generated microcracks, and the cleaning efficiency will decrease.

  Therefore, when the inner diameter of the injection hole 31 provided in the orifice pipe 30 is 0.1 to 1.5 mm and the inner diameter of the gas hole 32 is 0.1 to 0.3 mm, the inner diameter of the generation pipe 28 is It is formed within a range of 1.0 to 30.0 mm and a length of 15 to 500 mm.

  Since the diameter of the injection hole 31 of the orifice pipe 30 is reduced to, for example, about 0.1 to 1.5, the generation of static electricity generated at the time of injection can be reduced as much as possible. Economical.

  In the embodiment, the ring formed by a plurality of gas holes 32 provided annularly on the peripheral edge of the orifice pipe 30 is formed by double each, but the number of gas holes forming this ring and The single or double number of rings is not limited to the present embodiment.

  Next, the dry ice snow W generated in the generating pipe 28 flows down in the direction of the mixing chamber 22 of the nozzle body 21, and is agitated and mixed with the compressed air Y pumped from the compressor 15 in the mixing chamber 22 to be uniformized. The cleaning efficiency can be increased by spraying the object to be cleaned from the injection port 38 of the acceleration tube 35.

  The conventional production tube 65 shown in FIGS. 6 and 7 cannot form the diffusion suppressing cylindrical membrane portion S in the cylinder, and therefore cannot block the heat transmitted from the outer periphery, and the temperature in the cylinder is −78 ° C. It took time to create a low-temperature atmosphere, and during that time, the liquefied gas X had to be discharged unnecessarily, which was uneconomical because the production cost was high. The diffusion suppressing cylindrical membrane portion S can be quickly formed from the gas hole 32 in the production tube 28, and the low temperature atmosphere of -78 ° C. can be quickly formed in the cylinder by blocking the heat transmitted from the outside. Therefore, the liquefied gas X injected into the low-temperature atmosphere in the generation pipe 28 has an advantage that the dry ice snow W can be generated efficiently because there is little influence transmitted from the outside.

  As shown in FIG. 6, the conventional orifice pipe 60 has no gas holes, and therefore has no gas holes around the injection hole 61 located in the center. Therefore, external heat affects the generation pipe 65, When the liquefied gas in the generating pipe 65 having a large inner diameter is ejected from the injection hole, a swirl flow is generated in the pipe, and the dry ice snow W generated in the pipe comes into contact with the inner wall surface of the generating pipe by the swirl flow. As a result, the production loss of the dry ice snow W is large and the efficiency may be deteriorated. However, since the present invention can quickly form the diffusion suppressing cylindrical membrane portion S on the inner surface of the production tube 28, the generation of the spiral flow is prevented, the loss of sublimation in contact with the inner wall surface is prevented, and the production efficiency is improved. Improvements can be made.

  Compressed air Y as a pressurized fluid is pressurized to about 0.6 to 0.8 MPa by a compressor and increases the flow velocity by passing through a narrow path 37 formed in a tapered shape in the acceleration pipe 35. It sprays on the surface of a to-be-cleaned object from the injection port 38. The dry ice snow sprayed from the injection port 38 generates micro cracks due to thermal shock on the surface of the object to be cleaned, and the surface can be cleaned efficiently by the expansion energy when the dry ice snow enters the crack. It is.

DESCRIPTION OF SYMBOLS 10 Cleaning apparatus 12 Liquefied carbon dioxide container 13 Gas hose 14 On-off valve 15 Compressor 16 Air hose 17 On-off valve 20 Injection nozzle 21 Nozzle body 22 Mixing chamber 23 Supply path 24 Air supply path 25 Injection path 28 Generation pipe 30 Orifice pipe 31 Injection hole 32 Gas Hole 35 Accelerating tube 36 Flow path 38 Injection port S Diffusion control cylindrical membrane part W Dry ice snow X Liquefied carbon dioxide Y Compressed air

Claims (4)

A mixing chamber (22) for mixing dry ice snow (W) and compressed air (Y) is provided inside, and a supply path (23), an air supply path (24), and an injection path (25) are respectively provided in the mixing chamber. A production pipe (28) for injecting liquefied carbon dioxide (X) into the pipe to generate dry ice snow (W) is attached to the supply passage (23) side of the nozzle body (21) formed in communication. An injection hole (31) for injecting liquefied carbon dioxide (X) in the central axis direction is provided upstream of the production pipe, and a plurality of the same is used to inject liquefied carbon dioxide (X) on the same circumference of the periphery of the injection hole. An orifice pipe (30) provided with a gas hole (32) is connected, and the dry ice snow (W) and the compressed air (Y) are jetted simultaneously onto the jet passage (25) side of the nozzle body (21). Acceleration tube (35) with outlet (38) at the tip is connected Becomes Te,
An air hose (16) having one end connected to a compressor (15) is connected to the air supply path (24) of the nozzle body (21), and liquefied carbon dioxide (X) is accommodated upstream of the orifice pipe (30). A spray nozzle for a dry ice snow cleaning apparatus, wherein the other end of a gas hose (13) having one end connected to the container 12 is connected.   The spray nozzle for a dry ice snow cleaning device according to claim 1, wherein the inner diameter D of the production pipe (28) is 1.0 to 30.0 mm, and the length L of the production pipe is 15 to 500 mm. .   The orifice pipe (30) is formed by arranging a plurality of gas holes (32) in a single or double ring shape on the same circumference of the peripheral edge of the injection hole (31) provided in the central axial direction. The spray nozzle for a dry ice snow cleaning device according to claim 1.   The orifice pipe (30) has an inner diameter d of an injection hole (31) provided at the center of 0.1 to 1.5 mm, and an inner diameter of a plurality of gas holes (32) provided at the periphery of the injection hole. 4. The spray nozzle for a dry ice snow cleaning apparatus according to claim 1, wherein the spray nozzle is formed to have a thickness of 0.1 to 0.3 mm.

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