Dry ice snow cleaning device

Abstract

To provide a dry ice snow cleaning device that can prevent dew condensation and freezing from occurring due to a decrease in temperature of an injection nozzle, can inject a mixed gas containing dry ice snow at a wide angle and a high speed, and has excellent cleaning efficiency.SOLUTION: A dry ice snow cleaning device includes: a liquefied carbon dioxide gas supply path that supplies a liquefied carbon dioxide gas G1 while adjusting the pressure and temperature of the gas; an assist gas supply path that supplies an inert gas or compressed air as an assist gas G3; a jet nozzle 2 which is located at an outlet side of the liquefied carbon dioxide gas supply path, jets a mixed gas G4 obtained by combining dry ice snow G2 generated from the liquefied carbon dioxide gas G1 and the assist gas G3 from a jet port 43a to the object to be cleaned. The jet nozzle 2 includes a slit flow passage 25 having a multi-pipe structure with double or more pipes and communicating with an injection port 43a to restrict the injection direction of the mixed gas G4, and jets the mixed gas G4 from the slit flow passage 25 in a flat plate shape.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a dry ice snow cleaning device. [Background technology]

[0002] Conventionally, for example, an apparatus as shown in Patent Document 1 has been disclosed as a dry ice snow cleaning apparatus including a cleaning nozzle for spraying dry ice snow onto objects to be cleaned, such as machine parts such as gears and chains, and molds.

[0003] In addition, as a nozzle for spraying a jet of dry ice particles merged with a carrier gas at a wide angle, and a dry ice snow cleaning device equipped with the same, for example, an apparatus as shown in Patent Document 2 has been disclosed. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2022-061177 [Patent Document 2] JP 2019-209414 A Summary of the Invention [Problem to be solved by the invention]

[0005] When cleaning an object to be cleaned using the conventional devices disclosed in Patent Documents 1 and 2, the cleaning nozzle may be cooled, condensed, or frozen because a mixed gas containing dry ice snow is sprayed from the tip of the cleaning nozzle. Therefore, when the devices of Patent Documents 1 and 2 are operated continuously for a long period of time, the spray state of the mixed gas may become unstable, and the cleaning efficiency of the object to be cleaned may decrease.

[0006] The present invention has been made in consideration of the above problems, and provides a dry ice snow cleaning device that can prevent the temperature of the spray nozzle from dropping and causing condensation or freezing even when operated for a long period of time, and can spray mixed gas containing dry ice snow at a wide angle and at high speed, thereby achieving excellent cleaning efficiency. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention includes the following aspects. [1] A dry ice snow cleaning device that cleans an object by spraying dry ice snow toward the object, a liquefied carbon dioxide gas supply path for delivering liquefied carbon dioxide gas stored in a liquefied carbon dioxide gas supply source or liquefied carbon dioxide gas contained in a liquefied carbon dioxide gas cylinder; An assist gas supply path for supplying an inert gas or compressed air as an assist gas; A spray nozzle is provided at the outlet side of the liquefied carbon dioxide gas supply path, and sprays a mixed gas obtained by mixing the dry ice snow generated from the liquefied carbon dioxide gas and the assist gas from a spray nozzle onto the object to be cleaned. The dry ice snow cleaning device is characterized in that the injection nozzle has a multi-tube structure with two or more pipes, and is equipped with a slit flow path that communicates with the injection port and limits the injection direction of the mixed gas, and the mixed gas is injected in a flat plate shape from the slit flow path. [2] The injection nozzle is The dry ice snow cleaning device described in [1] above is characterized in that it includes, in this order from the liquefied carbon dioxide supply path side, an orifice section that regulates the flow path area of ​​the liquefied carbon dioxide supplied from the liquefied carbon dioxide supply path, and a granulation section that adiabatically expands the liquefied carbon dioxide sprayed from the orifice section and granulates it to generate dry ice snow of a predetermined particle size, and has a liquefied carbon dioxide flow path arranged on the central axis of the spray nozzle. [3] The injection nozzle is a first assist gas flow path that is arranged so as to surround the liquefied carbon dioxide gas flow path, and that has a large diameter section, a throttle section, and a small diameter section arranged in this order from the assist gas supply path side, and into which the assist gas is introduced from the large diameter section side; a second assist gas flow passage disposed so as to surround the first assist gas flow passage, the small diameter portion of the first assist gas flow passage has a through hole through which the assist gas flows toward the second assist gas flow passage, The dry ice snow cleaning device described in [2] above, characterized in that the second assist gas flow passage has an assist gas injection port that injects the assist gas from around the slit flow passage in parallel with the mixed gas injected from the slit flow passage. [4] The injection nozzle is The dry ice snow cleaning device described in [2] or [3] above, characterized in that the granulation section in the liquefied carbon dioxide gas flow path is structured so that a granulation injection port for injecting the dry ice snow is positioned at a position corresponding to the small diameter section in the first assist gas flow path, thereby enabling a negative pressure to be maintained within the granulation section. Effect of the Invention

[0008] According to the dry ice snow cleaning device of the present invention, as described above, a configuration is adopted in which a spray nozzle having a multi-tube structure is provided, which sprays the mixed gas obtained by merging the dry ice snow and the assist gas in a flat shape from the slit flow path. In this way, first, by making the spray nozzle a multi-tube structure, it is possible to optimize the arrangement relationship between the flow path of the liquefied carbon dioxide gas and the flow path of the assist gas, so that even if the device is operated for a long time, the temperature drop of the spray nozzle caused by the dry ice snow is suppressed, and condensation and freezing can be prevented. In addition, by spraying the mixed gas made by mixing with the assist gas in a flat shape from the slit flow path, it is possible to spray the mixed gas containing the dry ice snow at a wide angle and at high speed. Therefore, it is possible to clean the object to be cleaned with excellent cleaning efficiency regardless of the operation time, etc. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram illustrating a dry ice snow cleaning device according to one embodiment of the present invention, and is a system diagram showing the overall configuration of the dry ice snow cleaning device. [Diagram 2] FIG. 2 is a schematic diagram illustrating a dry ice snow cleaning device according to one embodiment of the present invention, and is a cross-sectional view taken along the axial direction of a spray nozzle showing an example of a spray nozzle that can be applied to the dry ice snow cleaning device shown in FIG. [Diagram 3] FIG. 2 is a schematic diagram illustrating a dry ice snow cleaning device according to one embodiment of the present invention, and is a cross-sectional view taken along the axial direction of the spray nozzle, showing a modified example of a spray nozzle that can be applied to the dry ice snow cleaning device shown in FIG. [Figure 4] FIG. 2 is a schematic diagram illustrating a dry ice snow cleaning device according to one embodiment of the present invention, and is a cross-sectional view taken along the axial direction of the spray nozzle, showing a modified example of a spray nozzle that can be applied to the dry ice snow cleaning device shown in FIG. [Diagram 5] FIG. 2 is a schematic diagram illustrating a dry ice snow cleaning device according to another embodiment of the present invention, and is a cross-sectional view taken along the axial direction of a jet nozzle, showing an example of a jet nozzle that can be applied to the dry ice snow cleaning device shown in FIG. [Figure 6] FIG. 2 is a schematic diagram illustrating a dry ice snow cleaning device according to another embodiment of the present invention, and is a cross-sectional view taken along the axial direction of the spray nozzle, showing a modified example of a spray nozzle that can be applied to the dry ice snow cleaning device shown in FIG. [Figure 7] FIG. 2 is a schematic diagram illustrating a dry ice snow cleaning device according to another embodiment of the present invention, and is a cross-sectional view taken along the axial direction of the spray nozzle, showing a modified example of a spray nozzle that can be applied to the dry ice snow cleaning device shown in FIG. [Figure 8]8A to 8C are diagrams for illustrating a dry ice snow cleaning device according to one embodiment of the present invention, and each of Figs. 8A to 8C is a plan view showing an example of an injection nozzle having a structure shown in the cross-sectional view of any one of Figs. 2, and 4 to 8, as viewed from the tip side. [Figure 9] 9A and 9B are schematic diagrams illustrating a dry ice snow cleaning device according to one embodiment of the present invention, and are perspective views each showing an example of a spray nozzle having the structure shown in the cross-sectional view of FIG. 2. [Figure 10] 10A and 10B are schematic diagrams illustrating a dry ice snow cleaning device according to one embodiment of the present invention, and are perspective views each showing an example of a spray nozzle having the structure shown in the cross-sectional view of FIG. 3. [Figure 11] 11A and 11B are diagrams for illustrating a dry ice snow cleaning device according to one embodiment of the present invention, and are perspective views each showing an example of a spray nozzle having the structure shown in the cross-sectional view of FIG. 4. [Figure 12] 12A and 12B are schematic diagrams illustrating a dry ice snow cleaning device according to another embodiment of the present invention, in which FIG. 12A is a plan view showing an example of a spray nozzle seen from the tip side, FIG. 12B is a perspective view showing an example of a spray nozzle having the planar shape shown in FIG. 12A, and FIGS. 12C and 12D are perspective views showing other modified examples. [Figure 13] FIG. 2 is a schematic diagram illustrating a dry ice snow cleaning device according to another embodiment of the present invention, and is a cross-sectional view taken along the axial direction of a jet nozzle, showing an example of a jet nozzle that can be applied to the dry ice snow cleaning device shown in FIG. [Figure 14] FIG. 2 is a schematic diagram illustrating a dry ice snow cleaning device according to another embodiment of the present invention, and is a cross-sectional view taken along the axial direction of the spray nozzle, showing a modified example of a spray nozzle that can be applied to the dry ice snow cleaning device shown in FIG. [Figure 15]FIG. 2 is a schematic diagram illustrating a dry ice snow cleaning device according to another embodiment of the present invention, and is a cross-sectional view taken along the axial direction of the spray nozzle, showing a modified example of a spray nozzle that can be applied to the dry ice snow cleaning device shown in FIG. [Figure 16] 16A to 16C are diagrams for typically explaining a dry ice snow cleaning device according to another embodiment of the present invention, and are plan views each showing an example of the injection nozzle shown in the cross-sectional view of any one of FIGS. 13 to 16, as viewed from the tip side. [Figure 17] 17A and 17B are diagrams for typically explaining a dry ice snow cleaning device according to another embodiment of the present invention, and are perspective views each showing an example of the structure of the injection nozzle shown in the cross-sectional view of FIG. 13. [Figure 18] 18A and 18B are schematic views illustrating a dry ice snow cleaning device according to another embodiment of the present invention, and are perspective views each showing an example of the structure of the injection nozzle shown in the cross-sectional view of FIG. [Figure 19] 19A and 19B are schematic diagrams illustrating a dry ice snow cleaning device according to another embodiment of the present invention, and are perspective views each showing an example of the structure of the injection nozzle shown in the cross-sectional view of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] A dry ice snow cleaning device according to an embodiment of the present invention will be described below with reference to Figures 1 to 19. The drawings used in the following description may show characteristic parts in an enlarged scale for the sake of convenience in order to make the characteristics easier to understand, and the dimensional ratios of each component may not necessarily be the same as in reality. In addition, the materials exemplified in the following description are merely examples, and the present invention is not limited to them, and may be modified as appropriate within the scope of the present invention.

[0011] The dry ice snow cleaning device according to the present invention cleans the object by spraying dry ice snow toward it. Examples of such objects include mechanical structural parts such as gears and chains, as well as objects such as molds that require removal of foreign matter from the surface to maintain normal operation. In addition, the dry ice snow cleaning device according to the present invention can also be used to cool the object to be cleaned by spraying dry ice snow toward the object.

[0012] <Overall configuration of dry ice snow cleaning device> The overall configuration of the dry ice snow cleaning device of this embodiment will be described with reference to the drawings.

[0013] Fig. 1 is a system diagram showing the overall configuration of a dry ice snow cleaning device (hereinafter, sometimes simply referred to as a cleaning device) 1 of this embodiment. Fig. 2 is a cross-sectional view taken along the axial direction of the injection nozzle 2, showing an example of an injection nozzle 2 applicable to the cleaning device 1 shown in Fig. 1. 8(a) to (c) are plan views showing examples of the injection nozzle 2 having the structure shown in the cross-sectional view of FIG. 2 (or any one of FIGS. 3 to 8), as viewed from the tip 22 side. 9(a) and 9(b) are perspective views each showing a schematic configuration of the injection nozzle 2 having the structure shown in the cross-sectional view of FIG.

[0014] As shown in FIG. 1, the cleaning device 1 of this embodiment is generally configured to include a liquefied carbon dioxide gas supply path L1, an assist gas supply path L2, an injection nozzle 2, an solenoid valve 5, a liquefied carbon dioxide gas supply source 6, and an assist gas supply source 9.

[0015] In the cleaning device 1 of this embodiment, the spray nozzle 2 is located on the outlet side of the liquefied carbon dioxide gas supply path L1, and a mixed gas G4 obtained by combining dry ice snow G2 generated from liquefied carbon dioxide gas G1 and assist gas G3 is sprayed from the spray nozzle 43a through the slit flow path 25 onto the object to be cleaned (not shown). As shown in FIG. 2, the injection nozzle 2 has a multiple pipe structure having a double pipe or more, and in the illustrated example, it has a triple pipe structure consisting of a second assist gas flow path 4B, a first assist gas flow path 4A, and a liquefied carbon dioxide gas flow path 3 from the injection nozzle main body 21 side, the details of which will be described later.

[0016] In this embodiment, a slit flow path 25 is provided so that the injection nozzle 2 communicates with an injection port 43a provided on the downstream tip 22 side in the gas flow direction, and although detailed illustration is omitted, the mixed gas G4 is injected in a flat plate shape from the slit flow path 25.

[0017] The liquefied carbon dioxide gas supply path L1 is disposed between the liquefied carbon dioxide gas supply source 6 and the injection nozzle 2, and is a liquid delivery path for supplying the liquefied carbon dioxide gas G1 derived from the liquefied carbon dioxide gas supply source 6 to the injection nozzle 2, the details of which will be described later. Specifically, one end of the liquefied carbon dioxide gas supply path L1 is connected to the liquefied carbon dioxide gas supply source 6, and the other end is connected to a liquefied carbon dioxide gas inlet flow path 23 that communicates with the liquefied carbon dioxide gas flow path 3 of the injection nozzle 2. As the liquefied carbon dioxide gas supply path L1, for example, a pipe made of a material having low gas permeability and excellent pressure resistance, such as a stainless steel material or a resin material, can be used.

[0018] The liquefied carbon dioxide gas supply path L1 has an inner space that serves as a liquid delivery path for the liquefied carbon dioxide gas. Here, in this embodiment, the flow path area of ​​the liquefied carbon dioxide gas supply path L1 and the liquid delivery path for the liquefied carbon dioxide gas G1 inside the injection nozzle 2 refers to the cross-sectional area of ​​the liquid delivery path for the liquefied carbon dioxide gas G1 in the liquid delivery direction, i.e., in the direction perpendicular to the central axis J of the injection nozzle 2.

[0019] 1 and 2, the flow path area of ​​the liquefied carbon dioxide gas supply path L1 is constant up to the connection with the liquefied carbon dioxide gas inlet flow path 23 of the injection nozzle 2. Therefore, in the liquefied carbon dioxide gas supply path L1 constituting the liquefied carbon dioxide gas G1 delivery path, the liquefied carbon dioxide gas G1 does not undergo adiabatic expansion and dry ice snow G2 is not generated, thereby suppressing blockage of the flow path.

[0020] 1, a solenoid valve 5 is disposed in the liquefied carbon dioxide gas supply path L1 between the liquefied carbon dioxide gas supply source 6 and the injection nozzle 2. According to the cleaning device 1 of the present embodiment, the open / close state of the liquefied carbon dioxide gas supply path L1 can be selected by operating the solenoid valve 5.

[0021] 2, the injection nozzle 2 has an injection nozzle body 21. The injection nozzle 2 in the illustrated example injects mixed gas G4 containing dry ice snow (dry ice) G2 generated in a granulation unit 32 (to be described later) constituting the liquefied carbon dioxide gas flow path 3 from an injection port 43a through a slit flow path 25 of the injection nozzle body 21.

[0022] The injection nozzle body 21 is, for example, a cylindrical member having openings on both ends. Inside the injection nozzle body 21, a liquefied carbon dioxide gas flow path 3 including a granulation section 32 is provided, into which liquefied carbon dioxide gas G1 is introduced from a liquefied carbon dioxide gas inlet flow path 23 on the base end side (upstream side of the gas flow). Meanwhile, the tip 22 side of the injection nozzle body 21 is formed as a slit flow path 25 for injecting a mixed gas G4 including dry ice snow G2. In addition, a liquefied carbon dioxide gas supply path L1, the details of which will be described later, is connected to the liquefied carbon dioxide gas inlet flow path 23.

[0023] The shape of the slit flow passage 25 is not particularly limited as long as the cross-sectional shape of the slit flow passage 25 in a direction perpendicular to the central axis J1 of the injection nozzle body 21 is slit-shaped and the mixed gas G4 containing the dry ice snow G2 can be injected.

[0024] FIG. 2 shows an example in which the tip 22 has a tapered, pointed shape with the outlet 25a of the slit flow passage 25 as the apex (see also the perspective views in FIG. 9(a) and the like).

[0025] 8(a) to (c) show examples of the shapes of the slit flow passage 25 and the assist gas ejection ports (44a, 44b, 44c) shown in Fig. 2 when viewed from the tip 22. As shown in Fig. 8(a) to (c), the slit flow passage 25 is formed so as to be cut into the side surface (body portion) of the ejection nozzle body 21.

[0026] Also, Fig. 8(a) shows an example in which the assist gas ejection port 44a is composed of multiple tubular flow paths. Fig. 8(b) shows an example in which two assist gas ejection ports 44b, which are arc-shaped in plan view and formed along the side surface of the ejection nozzle body 21, are provided. Fig. 8(c) shows an example in which two assist gas ejection ports 44c, which are linear in plan view and formed parallel to the slit flow path 25, are provided.

[0027] 9(a) and (b) show examples of the shape of the injection nozzle 2 having the structure shown in the cross-sectional view of Fig. 2, in a perspective view. That is, Fig. 9(a) shows an example in which the assist gas injection port 44a is composed of a plurality of tubular flow paths, as shown in the cross-sectional view of Fig. 2 and the plan view of Fig. 8(a). Fig. 9(b) shows an example in which two assist gas injection ports 44c are provided, which are linear in plan view and parallel to the slit flow path 25, as shown in the plan view of Fig. 8(c).

[0028] The slit width S7 of the slit flow passage 25 shown in Fig. 2, i.e., the dimension of the short side in the above-mentioned cross-sectional shape, is not particularly limited, but from the viewpoint of increasing the injection speed of the mixed gas G4 containing the dry ice snow G2 to a predetermined value or more, it is preferable to set it in the range of, for example, 0.25 to 1 mm, and more preferably about 0.5 mm. In the example shown in Fig. 1, the slit width S7 of the slit flow passage 25 is set to a dimension slightly larger than the dimension of the injection port 43a in the direction along the slit width S7.

[0029] Furthermore, the length S4 of the slit flow passage 25 is not particularly limited either, but is preferably in the range of 5 to 25 mm, and more preferably in the range of 10 to 15 mm, for example.

[0030] The internal space of the injection nozzle 2, i.e., the internal space of the injection nozzle body 21 shown in Fig. 2, is configured to be a substantially cylindrical space from the base end side, i.e., the liquefied carbon dioxide gas inlet passage 23 toward the tip 22. The injection nozzle body 21 is also provided with an assist gas inlet passage 24 for supplying an assist gas G3 to a first assist gas passage 4A, the details of which will be described later. An assist gas supply path L2, the details of which will be described later, is connected to this assist gas inlet passage 24.

[0031] The inner diameter of the liquefied carbon dioxide gas inlet passage 23 is not particularly limited, but is selected to be larger than the inner diameter of the orifice portion 31 of the liquefied carbon dioxide gas passage 3, the details of which will be described later, and to be a size that allows the liquefied carbon dioxide gas G1 to flow at approximately 600 g / min without any particular hindrance.

[0032] In addition, as described above, the tip of the injection nozzle 2, i.e., the tip 22 of the injection nozzle body 21, is provided with the slit flow path 25 communicating with the injection port 43a. The injection nozzle 2 injects the mixed gas G4, which is the mixture of the dry ice snow G2 generated in the liquefied carbon dioxide gas flow path 3 and the assist gas G3, from the slit flow path 25 in a generally flat shape.

[0033] According to the injection nozzle 2 provided in the cleaning device 1 of this embodiment, the injection nozzle 2 is provided with the slit flow passage 25 having the above-mentioned configuration, and is provided with a configuration for injecting the mixed gas G4 containing the dry ice snow G2 in a flat plate shape toward the object to be cleaned from the slit flow passage 25, so that the mixed gas G4 can be injected at a wide angle and at high speed. This improves the cleaning efficiency of the object to be cleaned to which the mixed gas G4 is injected. 8(a) to 8(c), when the slit flow path 25 is cut into the side (body) of the injection nozzle body 21, the mixed gas G4 containing the dry ice snow G2 can be injected at a wider angle. This increases the area of ​​injection of the mixed gas G4 onto the object to be cleaned, thereby improving the cleaning efficiency.

[0034] As described above, inside the injection nozzle body 21, the second assist gas flow path 4B, the first assist gas flow path 4A, and the liquefied carbon dioxide gas flow path 3 are arranged in this order from the injection nozzle body 21 side, forming a triple pipe structure.

[0035] 2, the liquefied carbon dioxide gas flow path 3 includes an orifice portion 31 that regulates the flow path area of ​​the liquefied carbon dioxide gas G1 supplied from the liquefied carbon dioxide gas supply path L1, and a granulation portion 32 that adiabatically expands the liquefied carbon dioxide gas G1 sprayed from the orifice portion 31, granulates it, and generates dry ice snow G2 of a predetermined particle size. The orifice portion 31 and the granulation portion 32 are disposed in this order from the liquefied carbon dioxide gas supply path L1 side, i.e., from the liquefied carbon dioxide gas inlet flow path 23 side. The liquefied carbon dioxide gas flow path 3 is disposed on the central axis J of the spray nozzle 2.

[0036] The orifice portion 31 is a tubular portion disposed on the inlet side of the liquefied carbon dioxide gas G1 in the liquefied carbon dioxide gas flow path 3 and provided so as to communicate with the liquefied carbon dioxide gas inlet flow path 23 to which the liquefied carbon dioxide gas supply path L1 is connected. That is, as shown in Fig. 2, the orifice portion 31 is configured to have a smaller diameter than the liquefied carbon dioxide gas inlet flow path 23, and after compressing the liquefied carbon dioxide gas G1 introduced from the inlet port 31a, the liquefied carbon dioxide gas G1 is discharged from the outlet port 31b toward the granulation portion 32 configured to have a larger diameter than the orifice portion 31. As a result, the liquefied carbon dioxide gas G1 is adiabatically expanded, and dry ice snow G2 is generated.

[0037] The inner diameter of the orifice portion 31 is not particularly limited as long as it is smaller than the liquefied carbon dioxide gas inlet passage 23 and the downstream granulation portion 32, but can be appropriately selected within the range of, for example, 0.1 to 2.5 mm. If the inner diameter of the orifice portion 31 is within this range, the liquefied carbon dioxide gas G1 can be effectively adiabatically expanded in the downstream granulation portion 32, and dry ice snow G2 can be efficiently produced.

[0038] Furthermore, the orifice portion 31 is not limited to a tubular one as in the illustrated example, but can be, for example, a metal plate (not shown) having a through hole of the same dimensions as the above-mentioned range of inner diameters, or a needle valve structure that can arbitrarily adjust the flow rate of the liquefied carbon dioxide gas G1.

[0039] The granulation section 32 is disposed so as to communicate with the discharge port 31b of the orifice section 31, and is a tubular member extending in the same direction as the orifice section 31. The granulation section 32 adiabatically expands the liquefied carbon dioxide gas G1 discharged from the discharge port 31b of the orifice section 31, granulates the gas into particles of a predetermined particle size to generate dry ice snow G2, and then continuously sprays the gas from the granulation injection port 32a into the inside of a small diameter section 43 of the first assist gas flow passage 4A, which will be described later.

[0040] The inner diameter S5 of the granulation section 32 is not particularly limited as long as it is larger than the inner diameter of the above-mentioned orifice section 31, and may be appropriately selected, for example, in the range of 0.3 to 2.5 mm, more preferably in the range of 1 to 2.2 mm, and larger than the inner diameter of the orifice section 31. If the inner diameter of the granulation section 32 is within this range, the liquefied carbon dioxide gas G1 introduced from the orifice section 31 can be effectively adiabatically expanded, and dry ice snow G2 having any particle size can be effectively granulated and generated.

[0041] The first assist gas flow passage 4A is disposed so as to surround the liquefied carbon dioxide gas flow passage 3, and the assist gas G3 flows through it. The first assist gas flow passage 4A in the example shown in Fig. 2 is configured to include a large diameter section 41, a throttle section 42, and a small diameter section 43 in this order from the assist gas supply path L2 side shown in Fig. 1. That is, the first assist gas flow passage 4A is configured so that the large diameter section 41 disposed on the base end side, the small diameter section 43 disposed on the tip 22 side of the injection nozzle main body 21, and the throttle section 42 disposed between the large diameter section 41 and the small diameter section 43 are each in communication with each other.

[0042] In the illustrated example, the first assist gas flow passage 4A is provided in the small diameter portion 43 with a through hole 43b for passing the assist gas G3 toward the second assist gas flow passage 4B, the details of which will be described later.

[0043] The large diameter portion 41 is a cylindrical space extending from the base end side toward the tip 22 side of the injection nozzle body 21. The granulation portion 32 constituting the above-mentioned liquefied carbon dioxide gas flow path 3 is arranged in the large diameter portion 41 so as to penetrate from the base end side toward the tip 22 side.

[0044] An assist gas inlet passage 24 provided in the injection nozzle body 21 is disposed at the position of the large diameter portion 41 in the first assist gas passage 4A. As a result, the first assist gas passage 4A is connected to the assist gas supply path L2 via the assist gas inlet passage 24. As a result, the assist gas G3 is introduced into the first assist gas passage 4A from the large diameter portion 41 side.

[0045] The small diameter portion 43 is a cylindrical space extending from the tip 22 side to the base end side of the injection nozzle main body 21. The granulation injection port 32a of the granulation section 32 constituting the above-mentioned liquefied carbon dioxide gas flow path 3 is opened in the small diameter portion 43. The tip side of the small diameter portion 43 is formed as an injection port 43a from which a mixed gas G4 of dry ice snow G2 and assist gas G3 is injected, and the slit flow path 25 in the injection nozzle main body 21 is arranged to communicate with this injection port 43a.

[0046] The small diameter portion 43 has a tapered shape in which the diameter gradually decreases near the connection with the injection port 43a, i.e., near the connection with the slit flow path 25, toward the slit flow path 25. The taper angle A1 of this portion is not particularly limited, but can be appropriately selected from the range of 90 to 120° about the central axis J, taking into consideration the injection speed of the mixed gas G4 from the injection port 43a, etc.

[0047] With the above-described configuration, the small diameter section 43 uniformly mixes the granulated dry ice snow G2 and the assist gas G3 injected from the granulation injection port 32a of the granulation section 32, and injects the mixture toward the slit flow path 25 from the injection port 43a.

[0048] The narrowed portion 42 is a tapered space formed so as to gradually reduce in diameter from the base end side to the tip end 22 side of the injection nozzle body 21. Through such narrowed portion 42, the large diameter portion 41 and the small diameter portion 43 described above communicate with each other.

[0049] As shown in Fig. 2, the cross-sectional area of ​​the small diameter portion 43 in the direction perpendicular to the central axis J of the injection nozzle 2 (injection nozzle body 21) is smaller than that of the large diameter portion 41. The cross-sectional area of ​​the throttle portion 42 continuously decreases from the large diameter portion 41 side toward the small diameter portion 43 side. In other words, when viewed in cross section on a plane parallel to the central axis J and including the central axis J in the internal space of the injection nozzle body 21, the diameter of the cylindrical space is smaller in the small diameter portion 43 than in the large diameter portion 41. When the throttle portion 42 is viewed in cross section in the same manner as the large diameter portion 41 and the small diameter portion 43, the diameter of the throttle portion 42 continuously decreases from the large diameter portion 41 side toward the small diameter portion 43 side.

[0050] The diameter S8 of the large diameter portion 41 is not particularly limited, and can be set appropriately depending on the inner diameter of the injection nozzle body 21. Further, the diameter S6 of the small diameter portion 43 is not particularly limited either, and may be appropriately selected so long as it is larger than the outer diameter of the granulation portion 32 constituting the liquefied carbon dioxide gas flow path 3 and is within the range of, for example, 20 mm or less.

[0051] As described above, the second assist gas flow passage 4B is disposed so as to surround the periphery of the first assist gas flow passage 4A in the triple-pipe structure injection nozzle 2. The assist gas G3 is introduced into the second assist gas flow passage 4B from the first assist gas flow passage 4A through the through-hole 43b provided in the small diameter section 43 of the first assist gas flow passage 4A.

[0052] 2, the second assist gas flow passage 4B has an assist gas ejection port 44a on the tip 22 side of the injection nozzle 2, which ejects an assist gas G3 from the periphery of the slit flow passage 25 in parallel with the mixed gas G4 ejected from the ejection port 43a through the slit flow passage 25. In the illustrated example, the assist gas G3 is ejected from the assist gas ejection port 44a which is the tip of the assist gas ejection passage 44.

[0053] In the above-mentioned first assist gas flow passage 4A, the center-to-center distance S1 from the assist gas inlet flow passage 24 to the through hole 43b in the direction along the central axis J is smaller than the distance S2 from the center of the assist gas inlet flow passage 24 to the granulation nozzle 32a of the granulation section 32, and is preferably set appropriately in the range of 5 to 30 mm. By setting the center-to-center distance S1 from the assist gas inlet flow passage 24 to the through hole 43b in the above range, the assist gas G3 can be efficiently introduced from the through hole 43b located in the small diameter section 43 toward the second assist gas flow passage 4B.

[0054] Furthermore, the distance S2 from the center of the assist gas inlet flow passage 24 to the granulation nozzle 32a of the granulation section 32 in the direction along the central axis J is preferably smaller than the distance S3 from the center of the assist gas inlet flow passage 24 to the nozzle 43a at the tip of the small diameter section 43, and is appropriately set within the range of 30 to 150 mm. By setting the distance S2 within the above range, it becomes possible to uniformly mix the dry ice snow G2 and the assist gas G3 sprayed from the granulation nozzle 32a in the small diameter section 43 of the first assist gas flow passage 4A.

[0055] In this embodiment, it is preferable that the granulation nozzle 32a provided in the granulation section 32 of the liquefied carbon dioxide gas flow path 3 for spraying the granulated dry ice snow G2 is arranged at a position corresponding to the small diameter section 43 in the first assist gas flow path 4A, thereby making it possible to maintain a negative pressure inside the granulation section 32. As described above, by arranging the granulation nozzle 32a of the granulation section 32 in the small diameter section 43 of the first assist gas flow path 4A, it is possible to achieve a structure that can maintain a negative pressure inside the granulation section 32 by the so-called Venturi effect. This makes it possible to prevent blockage of the inside of the granulation section 32 by the dry ice snow G2.

[0056] The assist gas supply path L2 is located between the assist gas supply source 9 and the injection nozzle 2, and is a path for supplying the assist gas derived from the assist gas supply source 9 to the injection nozzle 2. As the assist gas supply path L2, for example, a pipe made of a material having low gas permeability and excellent pressure resistance can be used.

[0057] Specifically, one end of the assist gas supply path L2 is connected to the assist gas supply source 9, and the other end is connected to the assist gas inlet flow path 24 in the injection nozzle body 21. This allows the assist gas G3 to be supplied to the first assist gas flow path 4A and the second assist gas flow path 4B in the injection nozzle 2, and the mixed gas G4 of the dry ice snow G2 and the assist gas G3 can be injected from the injection port 43a through the slit flow path 25.

[0058] The type of gas used as the assist gas G3 is not particularly limited, but may be, for example, an inert gas or compressed air. In addition, the assist gas G3 may be nitrogen gas, which is an inert gas.

[0059] 1, an electromagnetic valve 7 and an adjustment valve 8 are disposed in the assist gas supply path L2. In the cleaning device of this embodiment, the electromagnetic valve 7 can select the open / close state of the assist gas supply path L2, and the adjustment valve 8 can adjust the supply amount of the assist gas G3.

[0060] According to the cleaning device 1 of this embodiment, as described above, first, by making the injection nozzle 2 have a multiple pipe structure, it becomes possible to arrange the liquefied carbon dioxide gas flow path 3 on the central axis J side and arrange the first assist gas flow path 4A and the second assist gas flow path 4B on the outside thereof. This makes it possible to suppress a decrease in temperature of the injection nozzle 2 caused by the dry ice snow G2, and to prevent condensation and freezing, even when the device is operated for a long period of time. In addition, the dry ice snow G2 mixed with the assist gas G3 to form the mixed gas G4 is sprayed in a flat plate shape from the slit flow path 25, so that the mixed gas G4 containing the dry ice snow G2 can be sprayed at a wide angle and high speed. Therefore, the object to be cleaned can be cleaned with excellent cleaning efficiency regardless of the operation time, etc.

[0061] In addition, as in the example described in this embodiment, when the mixed gas G4 injected from the slit flow path 25 is restricted from diffusing in the vertical direction from the slit flow path 25 by the assist gas G3 injected from the assist gas injection port 44a, the injection speed of the mixed gas G4 is accelerated, and the cleaning power of the object to be treated is enhanced. In particular, as in the example shown in Fig. 8(c), when the assist gas injection port 44c, which is linear in plan view, is arranged parallel to the slit flow path 25 and is provided at two locations on either side of the slit flow path 25, the mixed gas G4 injected from the slit flow path 25 is easily accelerated, and the mixed gas G4 is less likely to diffuse in the up-down direction (vertical direction) in Fig. 8(c), which is preferable from the viewpoint of further enhancing the cleaning power of the object to be treated.

[0062] In addition, by adopting a configuration in which the assist gas G3 is injected from the assist gas injection port 44a, it is possible to prevent condensation in the slit flow path 25 that injects the mixed gas G4 of the dry ice snow G2 and the assist gas G3.

[0063] <How to operate the dry ice snow cleaning device> Hereinafter, a method of operating the cleaning device 1 for cleaning an object to be cleaned using the dry ice snow cleaning device 1 of this embodiment will be described with reference to the same drawings as above.

[0064] In operating the cleaning device 1 of this embodiment, first, the solenoid valve 5 is operated to open the liquefied carbon dioxide gas supply path L1. As a result, the liquefied carbon dioxide gas derived from the liquefied carbon dioxide gas supply source 6 is supplied to the liquefied carbon dioxide gas inlet passage 23 of the injection nozzle 2 via the liquefied carbon dioxide gas supply path L1.

[0065] As a result, the liquefied carbon dioxide G1 supplied from the liquefied carbon dioxide supply path L1 to the injection nozzle 2 becomes at the same pressure as that of the liquefied carbon dioxide supply source 6 in the orifice portion 31, and is injected into the inside of the granulation portion 32. The temperature of the liquefied carbon dioxide gas G1 introduced into the orifice portion 31 is preferably adjusted to be equal to or lower than the saturation temperature at the pressure of the liquefied carbon dioxide gas G1 to be sent. Also, it is preferable that the liquefied carbon dioxide gas G1 introduced into the orifice portion 31 is not in a gas-liquid mixed state.

[0066] The liquefied carbon dioxide gas G1 sprayed from the orifice section 31 into the inside of the granulation section 32 undergoes adiabatic expansion in the granulation section 32 and is granulated to an arbitrary particle size to produce dry ice snow G2, which is continuously sprayed from the granulation injection port 32a side into the small diameter section 43 of the first assist gas flow path 4A.

[0067] The flow rate of the dry ice snow G2 sprayed from the granulation nozzle 32a into the small diameter portion 43 can be appropriately adjusted according to, for example, the outlet area (opening area) of the nozzle 22a of the spray nozzle 2. Specifically, the flow rate of the dry ice snow G2 is preferably in the range of a flow rate when the flow rate of the liquefied carbon dioxide gas G1 is about 10 to 500 g / min.

[0068] Next, the supply amount of the assist gas G3 introduced into the injection nozzle 2 is adjusted. Specifically, the solenoid valve 7 is operated to open the assist gas supply path L2, and the supply pressure of the compressed assist gas G3 is adjusted by the adjustment valve 8. The supply pressure of the assist gas G3 is preferably adjusted to, for example, 0.2 MPaG or more. As a result, the assist gas G3 derived from the assist gas supply source 9 is supplied at a required pressure through the assist gas supply path L2 into the large diameter portion 41 of the first assist gas flow path 4A, which is the space inside the injection nozzle main body 21.

[0069] Next, the assist gas G3 introduced into the large diameter section 41 of the first assist gas flow passage 4A is transferred from the base end side of the injection nozzle 2 toward the tip end 22 side. That is, the assist gas G3 is transferred in the first assist gas flow passage 4A inside the injection nozzle body 21 from the large diameter section 41 to the narrowed section 42, and from the narrowed section 42 to the small diameter section 43, successively.

[0070] Here, in the space inside the injection nozzle body 21, i.e., in the first assist gas flow passage 4A, the cross-sectional area in the direction perpendicular to the axial direction of the injection nozzle body 21 is smaller in the small diameter section 43 than in the large diameter section 41, and in the constricted section 42, it gradually becomes smaller from the large diameter section 41 side toward the small diameter section 43 side. As a result, the flow velocity of the assist gas G3 introduced into the large diameter section 41 of the injection nozzle body 21 increases toward the small diameter section 43.

[0071] For example, by setting the supply pressure of the assist gas G3 to 0.2 MPaG or more, the pressure of the space inside the granulation section 32 that opens into the inside of the small diameter section 43 is adjusted to 0.05 to 0.09 MPa abs. This effectively prevents the granulation section 32 from being blocked when the dry ice snow G2 is generated.

[0072] Next, inside the small diameter portion 43 of the first assist gas flow passage 4A, the dry ice snow G2 sprayed from the granulation nozzle 32a of the granulation section 32 and the assist gas G3 join together to form a mixed gas G4. As a result, the flow rate of the mixed gas G4 containing the dry ice snow G2 is accelerated by the action of the assist gas G3, and the mixed gas G4 is sprayed from the nozzle 22a into the slit flow passage 25 at a required flow rate, and is sprayed from this slit flow passage 25 onto the object to be cleaned.

[0073] The flow velocity of the dry ice snow G2 is adjusted by the supply pressure and flow rate of the assist gas G3, but is preferably adjusted to be approximately 120 m / sec or more. Moreover, it is more preferable to adjust the temperature of the assist gas G3 to be equal to or higher than the outside air temperature (the temperature of the environment in which the cleaning device 1 is installed) before the assist gas G3 reaches the small diameter portion 43 where the assist gas G3 joins the dry ice snow G2.

[0074] Furthermore, in this embodiment, the assist gas G3 is introduced into the second assist gas flow passage 4B through the through hole 43b provided in the small diameter portion 43 of the first assist gas flow passage 4A, so that the assist gas G3 can be ejected from the assist gas ejection port 44a simultaneously with the ejection of the mixed gas G4 from the slit flow passage 25. At this time, on the tip 22 side of the injection nozzle 2, the assist gas G3 is ejected from the assist gas ejection port 44a in parallel with the mixed gas G4 ejected from the ejection port 43a via the slit flow passage 25.

[0075] In the cleaning device 1 of this embodiment, for example, a flow path may be provided for supplying a chemical agent to the space inside the injection nozzle 2 together with the assist gas G3. Specifically, the chemical agent is supplied together with the assist gas G3 to the space inside the injection nozzle body 21, for example, to the large diameter portion 41 of the first assist gas flow path 4A.

[0076] The above-mentioned agent is not particularly limited, but may be any one or more of water with a freezing temperature of −78° C. or higher, an antibacterial agent, a disinfectant, and a surfactant. The agent is preferably added in a liquid state to the assist gas G3 and is then attached to the dry ice snow G2 and frozen. In addition, the agent is preferably a liquid or one having a viscosity or fluidity similar to that of a liquid.

[0077] As described above, in the cleaning device 1 of this embodiment, when a configuration for supplying a chemical agent is further provided, the chemical agent can be applied (added) to the particle surface of the dry ice snow G2 at the same time as the acceleration of the dry ice snow G2 due to the Venturi effect using the assist gas G3 as a driving fluid. That is, by supplying the chemical agent to the first assist gas flow path 4A of the injection nozzle 2 together with the assist gas G3, the chemical agent can be attached to the particle surface of the dry ice snow G2 and injected.

[0078] In addition, in the cleaning device 1 of the present embodiment, the solenoid valve 5 is provided in the liquefied carbon dioxide gas supply path L1, and the solenoid valve 7 is provided in the assist gas supply path L2, but there is no particular limitation as long as it is a means for selecting the open / closed state of the flow path. For example, a manual valve or the like may be provided instead of the solenoid valve.

[0079] <Another example of a spray nozzle provided in a dry ice snow cleaning device> Below, other examples of spray nozzles applicable to the dry ice snow cleaning apparatus 1 of this embodiment will be described with appropriate reference to Figures 3 to 24 (if necessary, also refer to the various drawings cited in the description of the overall configuration of the dry ice snow cleaning apparatus 1 as appropriate). In addition, in the description of other examples (variations) of the injection nozzle below, the same symbols may be given to components that are the same or similar in terms of shape or function, etc., and detailed descriptions of these components may be omitted.

[0080] 3 to 7 are cross-sectional views taken along the axial direction of each of the jet nozzles 2A to 2E, which are modifications of the jet nozzle applicable to the cleaning apparatus 1 shown in FIG. 10(a) and (b) are respectively perspective views showing an example of an injection nozzle 2A having the structure shown in the cross-sectional view of FIG. 3, and FIGS. 11(a) and (b) are respectively perspective views showing an example of an injection nozzle 2B having the structure shown in the cross-sectional view of FIG. 4. Figure 12(a) is a plan view showing an example of an injection nozzle 2F seen from the tip side, Figure 12(b) is an oblique view showing an example of an injection nozzle 2F having the planar view shape shown in Figure 12(a), and Figures 12(c) and (d) are oblique views showing modified examples of the injection nozzle 2F. 13 to 15 are cross-sectional views taken along the axial direction of the jet nozzles 2G, 2H, and 2J, showing examples of jet nozzles applicable to the cleaning apparatus 1 shown in FIG. 16(a) to (c) are plan views showing an example of any one of the injection nozzles 2G, 2H, and 2J shown in the cross-sectional views of FIGS. 13 to 15, viewed from the tip end side. Figures 17(a) and (b) are respectively oblique views showing an example of the structure of the injection nozzle 2G shown in the cross-sectional view of Figure 13, Figures 18(a) and (b) are respectively oblique views showing an example of the structure of the injection nozzle 2H shown in the cross-sectional view of Figure 14, and Figures 19(a) and (b) are respectively oblique views showing an example of the structure of the injection nozzle 2J shown in the cross-sectional view of Figure 15.

[0081] First, the outline of the shapes of the jet nozzles 2A to 2E shown in Figs. 3 to 7 will be described. An injection nozzle 2A shown in FIG. 3 differs from the injection nozzle 2 having a tapered tip 22 as shown in FIG. 2 in that a tip 22A is flat. In addition, the injection nozzle 2B shown in FIG. 4 differs from the injection nozzle 2 having a tapered tip 22 as shown in FIG. 2 in that the tip 22B has a shape that expands from the outlet 25a of the slit flow path 25B as a starting point.

[0082] In addition, the injection nozzle 2C shown in FIG. 5 differs from the injection nozzle 2 shown in FIG. 2 in that the tip 22C has a tapered shape with the slit flow passage 25 as an apex, while the assist gas injection path 44C has a shape that is bent toward the central axis (see central axis J in FIG. 1) on the path toward the downstream side, so that the assist gas injection port 44 is positioned close to the outlet 25a of the slit flow passage 25. In addition, the injection nozzle 2D shown in FIG. 6 differs from the injection nozzle 2 shown in FIG. 2 in that the tip 22D is flat and the assist gas injection path 44D is bent toward the central axis (see central axis J in FIG. 1) on the path toward the downstream side, thereby positioning the assist gas injection port 44 close to the outlet 25a of the slit flow path 25. 7 differs from the injection nozzle 2 shown in FIG. 2 in that the injection nozzle 2E shown in FIG. 7 is shaped to expand from the exit 25a of the slit flow path 25B as a starting point, and further, the assist gas injection path 44E is shaped to bend toward the central axis (see central axis J in FIG. 1) on the path toward the downstream side, thereby positioning the assist gas injection port 44 close to the exit 25a of the slit flow path 25. As shown in the example in Figures 5 to 7, by arranging the assist gas ejection port 44 close to the outlet 25a of the slit flow path 25, the mixed gas G4 is prevented from diffusing in the up-down direction (vertical direction) in Figures 5 to 7, and the ejection speed of the mixed gas G4 is accelerated, thereby further improving the cleaning power of the workpiece.

[0083] Next, the outline of the shape of the injection nozzle 2A shown in FIGS. 10(a) and 10(b) will be described. FIG. 10(a) shows an example in which the tip 22A is configured in a flat shape, the assist gas ejection path is configured from multiple cylindrical flow paths, and multiple assist gas ejection ports 44a are arranged in an arc shape. FIG. 10(b) shows an example in which the assist gas ejection path is composed of two slit-shaped flow paths, and an assist gas ejection port 44c that is linear in plan view is formed in parallel to the slit flow path 25A.

[0084] Next, the outline of the shape of the injection nozzle 2B shown in FIGS. 11(a) and 11(b) will be described. Figure 11(a) shows an example in which the tip 22B is shaped to expand from the exit 25a of the slit flow path 25B as the starting point, and the assist gas injection path is composed of multiple cylindrical flow paths, and multiple assist gas injection ports 44a are arranged in an arc shape. FIG. 11(b) shows an example in which the assist gas ejection path is composed of two slit-shaped flow paths, and an assist gas ejection port 44c that is linear in plan view is formed in parallel to the slit flow path 25B.

[0085] Next, the outline of the shape of the injection nozzle 2F shown in Figs. 12(a) to (d) will be described. 12(a) to (d) show an example in which the assist gas injection path is composed of two slit-shaped flow paths at the nozzle tip, and an assist gas injection port 44c that is linear in plan view is formed parallel to the slit flow path 25F. Also, the assist gas injection port 44c in the illustrated example is formed so as to be cut into the side surface (body portion) of the injection nozzle main body 21, similar to the slit flow path 25. Figure 12(a) shows an example in which the nozzle tip is flat, Figure 12(b) shows an example in which the nozzle tip is tapered with the outlet 25a of the slit flow path 25F as its apex, and Figure 12(c) shows an example in which the nozzle tip is shaped to widen from the outlet 25a of the slit flow path 25F as its starting point.

[0086] Next, the outline of the shapes of the jet nozzles 2G, 2H, and 2J shown in Figs. 13 to 15 and Figs. 16(a) to (c), respectively, will be described. 13, the tip 22G is flat, and the assist gas injection path 45G is bent toward the central axis (see the central axis J in FIG. 1) in the path toward the downstream side, while the assist gas injection path 44G is linear. That is, the injection nozzle 2G has two systems of assist gas injection paths 44G, 45G.

[0087] 14, the tip 22H is tapered with the outlet 25a of the slit flow path 25H as the apex, and the assist gas injection path 45G is bent toward the central axis (see the central axis J in FIG. 1) in the path toward the downstream side, while the assist gas injection path 44G is linear. That is, the injection nozzle 2H also has two systems of assist gas injection paths 44H, 45H.

[0088] 15, the tip 22J is shaped to expand from the outlet 25a of the slit flow path 25J as a starting point, and the assist gas injection path 45J is shaped to bend toward the central axis (see the central axis J in FIG. 1) in the path toward the downstream side, while the assist gas injection path 44J is configured in a straight line. That is, the injection nozzle 2J also has two systems of assist gas injection paths 44J, 45J.

[0089] The injection nozzles 2G, 2H, 2J having two systems of assist gas injection paths as shown in Figures 13 to 15 may have planar shapes as shown in Figures 16(a) to 16(c) when viewed from the tip side. In the following, the planar shape of the injection nozzle G shown in Figure 13 as viewed from the tip 22G side will be described as an example. First, as shown in FIG. 16(a), the injection nozzle 2G can be configured in a planar view in which assist gas injection ports 44a are arranged at a total of 10 locations along the outer edge of the tip 22G, and a pair of assist gas injection ports 45a are arranged via a slit flow path 25G. Also, as shown in FIG. 16(b), it can be configured in a planar view having assist gas ejection ports 44b (corresponding to assist gas ejection ports 44a shown in FIG. 13) arranged at a total of two locations along the outer edge of the tip 22G, and a pair of assist gas ejection ports 45b (corresponding to assist gas ejection ports 45a shown in FIG. 13) arranged via a slit flow path 25G. Furthermore, as shown in Figure 16 (c), the nozzle can be configured in a planar shape in which two linear assist gas ejection ports 45c (corresponding to the assist gas ejection port 45a shown in Figure 13) are arranged parallel to the slit flow path 25G, and a pair of assist gas ejection ports 44c (corresponding to the assist gas ejection port 44a shown in Figure 13) are arranged opposite each other on the outside of the two linear assist gas ejection ports 45c (corresponding to the assist gas ejection port 44a shown in Figure 13).

[0090] In addition, the injection nozzles 2G, 2H, and 2J having two systems of assist gas injection paths as shown in Figures 13 to 15 have the structures shown in the oblique views of Figures 17(a) and (b), Figures 18(a) and (b), or Figures 19(a) and (b), respectively. For example, as shown in Fig. 17(a), the injection nozzle 2G shown in Fig. 13 has a flat tip 22G, and each assist gas injection path is composed of multiple cylindrical flow paths. The injection nozzle 2G shown in Fig. 17(a) has a structure in which multiple assist gas injection ports 44a are arranged in an arc shape along the outer edge of the tip 22G, and a pair of assist gas injection ports 45a are arranged via a slit flow path 25G. Alternatively, as shown in Fig. 17(b), the injection nozzle 2G may have a configuration in which the assist gas injection path is composed of two slit-shaped flow paths and a pair of cylindrical flow paths. The injection nozzle 2G shown in Fig. 17(b) has a structure in which a pair of linear assist gas injection ports 45a in a plan view are arranged in parallel to the slit flow path 25G, and a pair of assist gas injection ports 44a are arranged via the slit flow path 25G and the pair of assist gas injection ports 45a.

[0091] 14, for example, as shown in Fig. 18(a), the tip 22H is tapered with the outlet 25a of the slit flow passage 25H as the apex, and each assist gas injection passage is composed of a plurality of cylindrical flow passages. The injection nozzle 2H shown in Fig. 18(a) has a structure in which a plurality of assist gas injection ports 44a are arranged in an arc shape along the outer edge of the tip 22H, and a pair of assist gas injection ports 45a are arranged via the slit flow passage 25H. Alternatively, the injection nozzle 2H may have a configuration in which the assist gas injection path is composed of two slit-shaped flow paths and a pair of cylindrical flow paths, as shown in Fig. 18(b). The injection nozzle 2H shown in Fig. 18(b) has a structure in which a pair of linear assist gas injection ports 45a in a plan view are arranged in parallel to the slit flow path 25H, and a pair of assist gas injection ports 44a are arranged via the slit flow path 25H and the pair of assist gas injection ports 45a.

[0092] 15, the tip 22J is shaped to expand from the outlet 25a of the slit flow passage 25J as shown in Fig. 19(a), and the assist gas injection passage is composed of multiple tubular passages. The injection nozzle 2J shown in Fig. 19(a) has a structure in which multiple assist gas injection ports 44a are arranged in an arc shape along the outer edge of the tip 22J, and a pair of assist gas injection ports 45a are arranged via the slit flow passage 25J. Alternatively, as shown in Fig. 19(b), the injection nozzle 2J may have a configuration in which the assist gas injection path is composed of two slit-shaped flow paths and a pair of cylindrical flow paths. The injection nozzle 2J shown in Fig. 19(b) has a structure in which a pair of linear assist gas injection ports 45a in a plan view are arranged in parallel to the slit flow path 25J, and a pair of assist gas injection ports 44a are arranged via the slit flow path 25J and the pair of assist gas injection ports 45a.

[0093] Even when the spray nozzle of each of the above-mentioned modified examples is applied to the dry ice snow cleaning device of this embodiment, the temperature drop of the spray nozzle due to the dry ice snow is suppressed, preventing condensation and freezing, and by spraying the mixed gas containing the dry ice snow in a flat plate shape from the slit flow path, it is possible to spray at a wide angle and high speed.

[0094] <Action and effect> As described above, the dry ice snow cleaning device 1 of this embodiment employs a configuration including a jet nozzle 2 having a multiple tube structure that jets the mixed gas G4 obtained by merging the dry ice snow G2 and the assist gas G3 from the slit flow path 25 in a flat plate shape. In this way, first, by making the jet nozzle 2 have a multiple tube structure, it is possible to optimize the arrangement relationship between the flow path of the liquefied carbon dioxide gas G1 and the flow path of the assist gas G3, so that even if the device is operated for a long time, the temperature drop of the jet nozzle 2 caused by the dry ice snow G2 is suppressed, and condensation and freezing can be prevented. In addition, by jetting the mixed gas G4 obtained by mixing the dry ice snow G2 with the assist gas G3 in a flat plate shape from the slit flow path 25, it is possible to jet the mixed gas G4 containing the dry ice snow G2 at a wide angle and at high speed. Therefore, it is possible to clean the object to be cleaned with excellent cleaning efficiency regardless of the operation time, etc.

[0095] <Other forms> Although an example of the dry ice snow cleaning device according to the present invention has been described above by way of an embodiment, the present invention is not limited to the above embodiment. Each configuration and their combination in the above embodiment is merely an example, and addition, omission, substitution, and other modifications of the configuration are possible within the scope of the gist of the present invention.

[0096] For example, in the above-described embodiment, a dry ice snow cleaning device 1 configured using a spray nozzle 2 having a triple pipe structure has been described as an example, but the cleaning device according to the present invention also includes spray nozzles having other multiple pipe structures, such as a double pipe structure.

[0097] In addition, in the above-described embodiment, an example is shown in which liquefied carbon dioxide gas G1 is delivered and supplied from the liquefied carbon dioxide gas supply source 6 to the spray nozzle 2 via the liquefied carbon dioxide gas supply path L1, but the cleaning device according to the present invention also includes a configuration in which the liquefied carbon dioxide gas supply path L1 is directly attached to a liquefied carbon dioxide gas cylinder (not shown) and the liquefied carbon dioxide gas G1 is supplied to the spray nozzle 2.

[0098] In addition, in the examples shown in Figures 8(a) to (c), the slit flow path 25 is cut into the side (body) of the injection nozzle body, but for example, the slit flow path may not be cut into the side, and both ends of the slit flow path may be contained within the plane of the tip 22 of the injection nozzle. [Industrial Applicability]

[0099] The dry ice snow cleaning device of the present invention can prevent the temperature of the spray nozzle from dropping and causing condensation or freezing even when operated for a long period of time, and can spray mixed gas containing dry ice snow at a wide angle and at high speed, providing excellent cleaning efficiency. Therefore, the dry ice snow cleaning device of the present invention is very suitable for applications such as cleaning machine parts such as gears and chains, and molds. [Explanation of symbols]

[0100] 1. Dry ice snow cleaning device 2,2A,2B,2C,2D,2E,2F,2G,2H,2J,2K,2L,2M,2N,2P,2Q,2R…Injection nozzle 21…Injection nozzle body 22,22A,22B,22C,22D,22E,22F,22G,22H,22J,22K,22L,22M,22N,22P,22Q,22R…Tip 23...Liquefied carbon dioxide gas inlet passage 24...Assist gas inlet passage 25, 25A, 25B, 25C, 25D, 25E, 25F, 25G, 25H, 25J, 25K, 25L, 25M, 25N, 25P, 25Q, 25R...Slit flow path 25a...Exit 3...Liquefied carbon dioxide gas flow path 31...Orifice section 31a…Entrance 32...Granulation section 32a...Granulation injection port 4A…First assist gas flow path 41…Large diameter section 42…Through hole 43…Small diameter part 43a…Injection port 43b...Through hole 4B…Second assist gas flow path 44, 44C, 44D, 44E…Assist gas injection passage 44a, 44b, 44c, 45a, 45b, 45c...Assist gas nozzle 5...Solenoid valve 6...Liquid carbon dioxide gas supply source 7...Solenoid valve 8…Regulating valve 9…Assist gas supply source L1: Liquefied carbon dioxide gas supply route L2: Assist gas supply path J…Center axis G1: Liquefied carbon dioxide gas G2…Dry ice snow G3…Assist gas G4...Mixed gas (mixture of dry ice snow and assist gas)

Claims

1. A dry ice snow cleaning device that cleans an object by spraying dry ice snow toward the object, a liquefied carbon dioxide gas supply path for delivering liquefied carbon dioxide gas stored in a liquefied carbon dioxide gas supply source or liquefied carbon dioxide gas contained in a liquefied carbon dioxide gas cylinder; An assist gas supply path for supplying an inert gas or compressed air as an assist gas; A spray nozzle is provided at the outlet side of the liquefied carbon dioxide gas supply path, and sprays a mixed gas obtained by mixing the dry ice snow generated from the liquefied carbon dioxide gas and the assist gas from a spray nozzle onto the object to be cleaned. The dry ice snow cleaning device is characterized in that the injection nozzle has a multi-tube structure with two or more pipes, and is equipped with a slit flow path that communicates with the injection port and limits the injection direction of the mixed gas, and the mixed gas is injected in a flat plate shape from the slit flow path.

2. The injection nozzle is The dry ice snow cleaning device described in claim 1, characterized in that it includes, in this order from the liquefied carbon dioxide supply path side, an orifice section that regulates the flow path area of ​​the liquefied carbon dioxide supplied from the liquefied carbon dioxide supply path, and a granulation section that adiabatically expands the liquefied carbon dioxide sprayed from the orifice section and granulates it to generate dry ice snow of a predetermined particle size, and has a liquefied carbon dioxide flow path arranged on the central axis of the spray nozzle.

3. The injection nozzle is a first assist gas flow path that is arranged so as to surround the liquefied carbon dioxide gas flow path, and that has a large diameter section, a narrowed section, and a small diameter section arranged in this order from the assist gas supply path side, and into which the assist gas is introduced from the large diameter section side; a second assist gas flow passage disposed so as to surround the first assist gas flow passage, the small diameter portion of the first assist gas flow passage has a through hole through which the assist gas flows toward the second assist gas flow passage, The dry ice snow cleaning device according to claim 2, characterized in that the second assist gas flow passage has an assist gas injection port that injects the assist gas from around the slit flow passage in parallel with the mixed gas injected from the slit flow passage.

4. The injection nozzle is The dry ice snow cleaning device described in claim 2 or claim 3, characterized in that the granulation section in the liquefied carbon dioxide gas flow path is structured so that a granulation injection port for injecting the dry ice snow is positioned at a position corresponding to the small diameter portion in the first assist gas flow path, thereby enabling a negative pressure to be maintained within the granulation section.

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