Dry ice blasting equipment

Abstract

To provide a dry ice injection device which suppresses blockage of a liquid feeding path of liquefied carbon dioxide gas and can be continuously operated for a long time.SOLUTION: A dry ice injection device comprises: a liquefied carbon dioxide gas supply path L1 for supplying liquefied carbon dioxide gas; an orifice 4a which is positioned in the liquefied carbon dioxide gas supply path L1, and regulates a flow channel of the liquefied carbon dioxide gas; a granulation part 3 which is positioned on a secondary side of the orifice 4a; and an injection nozzle 2 for injecting dry ice. In a liquid feeding path of the liquefied carbon dioxide gas from the liquefied carbon dioxide gas supply path L1 to the orifice 4a, a flow channel area of the liquid feeding path is constant or decreases toward the secondary side from a primary side.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] Patent Document 1 discloses a dry ice spraying device including a cleaning nozzle for spraying dry ice snow. Furthermore, Patent Document 2 discloses a dry ice spraying device that can spray dry ice snow in a pulsed manner from a spray nozzle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4578644 [Patent Document 2] Patent No. 5065078 Summary of the Invention [Problem to be solved by the invention]

[0004] In the conventional dry ice spraying devices disclosed in Patent Documents 1 and 2, when operated continuously for a long period of time, there was a problem in that the liquefied carbon dioxide gas would adiabatically expand midway along the liquefied carbon dioxide gas delivery path, producing dry ice and causing the liquefied carbon dioxide gas delivery path to become blocked.

[0005] The present invention has been made in consideration of the above circumstances, and its object is to provide a dry ice spraying device that can prevent blockage of the liquefied carbon dioxide gas delivery path and can operate continuously for long periods of time. [Means for solving the problem]

[0006] In order to achieve the above object, the present invention employs the following configuration. [1] a liquefied carbon dioxide gas supply line for supplying liquefied carbon dioxide gas; an orifice located in the liquefied carbon dioxide gas supply path and regulating a flow path of the liquefied carbon dioxide gas; a granulation unit located on the secondary side of the orifice and communicating with the liquefied carbon dioxide gas supply path via the orifice; a spray nozzle for spraying the dry ice, A dry ice spraying device, wherein the flow path area of ​​the liquefied carbon dioxide gas supply path from the liquefied carbon dioxide gas supply path to the orifice is the same or decreases from the primary side to the secondary side. [2] The liquefied carbon dioxide gas supply path further includes an electromagnetic valve located on the primary side of the orifice, The dry ice spraying device described in [1], wherein the flow path area of ​​the liquid supply path, including the flow path inside the solenoid valve, is the same or decreases from the primary side to the secondary side. [3] The dry ice spraying device described in [1] or [2], wherein the tip of the granulation unit is located in the space inside the spray nozzle. [4] Further comprising a compressed gas supply path for supplying compressed gas; the compressed gas supply path is connected to the injection nozzle; The dry ice spraying device according to any one of [1] to [3], wherein the dry ice is sprayed from the spray nozzle together with the compressed gas. [5] A dry ice spraying device as described in [4], in which a chemical agent is supplied to the space inside the spray nozzle together with the compressed gas. [6] A dry ice spraying device according to any one of [1] to [5], wherein a needle valve is used as the orifice. [Effects of the Invention]

[0007] The dry ice spraying device of the present invention prevents clogging of the liquefied carbon dioxide gas delivery path and is capable of continuous operation for long periods of time. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a system diagram showing the configuration of a dry ice spraying device according to an embodiment of the present invention. [Figure 2] 1 is an enlarged cross-sectional view of the periphery of a needle valve of a dry ice spraying device according to an embodiment of the present invention. [Figure 3] 10 is a schematic diagram showing another configuration of the dry ice spraying device according to an embodiment of the present invention. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] The dry ice spraying device according to one embodiment of the present invention will be described in detail below with reference to the drawings. Note that the drawings used in the following description may show characteristic parts enlarged for convenience in order to make the characteristics easier to understand, and the dimensional proportions of each component may not necessarily be the same as those in reality.

[0010] First, the configuration of a dry ice spraying device according to one embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a system diagram showing a dry ice spraying device 1 according to one embodiment of the present invention. Fig. 2 is an enlarged cross-sectional view of the needle valve and its surroundings of the dry ice spraying device shown in Fig. 1.

[0011] As shown in Figure 1, the dry ice spraying device 1 of this embodiment is generally configured to include a liquefied carbon dioxide gas supply path L1, a compressed gas supply path L2, a spray nozzle 2, a granulation section 3, a needle valve 4, an electromagnetic valve 5, a liquefied carbon dioxide gas supply source 6, and a compressed gas supply source 9.

[0012] The liquefied carbon dioxide gas supply path L1 is located between the liquefied carbon dioxide gas supply source 6 and the needle valve 4, and is a liquid transfer path for supplying the liquefied carbon dioxide gas derived from the liquefied carbon dioxide gas supply source 6 to the needle valve 4, 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 second flow path 4b of the needle valve 4, which will be described later. A pipe made of a material with low gas permeability and excellent pressure resistance can be used as the liquefied carbon dioxide gas supply path L1.

[0013] 2, the inner space of the liquefied carbon dioxide gas supply path L1 serves as a path for transferring liquefied carbon dioxide gas. In this embodiment, the flow path area Dp of the liquefied carbon dioxide gas transfer path in the liquefied carbon dioxide gas supply path L1 is the cross-sectional area of ​​the liquefied carbon dioxide gas transfer path in a direction perpendicular to the transfer direction.

[0014] In this embodiment, the flow path area Dp of the liquefied carbon dioxide gas delivery path in the liquefied carbon dioxide gas supply path L1 is constant up to the connection point with the solenoid valve 5. Therefore, in the liquefied carbon dioxide gas supply path L1 that constitutes the carbon dioxide gas delivery path, the liquefied carbon dioxide gas does not undergo adiabatic expansion and dry ice is not produced, so clogging of the flow path can be suppressed.

[0015] 1, a solenoid valve 5 is located in the liquefied carbon dioxide gas supply path L1 on the upstream side of a needle valve 4. According to the dry ice spraying device 1 of this embodiment, the solenoid valve 5 can select whether the liquefied carbon dioxide gas supply path L1 is open or closed.

[0016] 2, the solenoid valve 5 has a liquefied carbon dioxide gas transfer path inside. Here, in this embodiment, the flow path area Dv of the liquefied carbon dioxide gas transfer path in the solenoid valve 5 is the cross-sectional area of ​​the liquefied carbon dioxide gas transfer path in a direction perpendicular to the transfer direction.

[0017] In this embodiment, the flow path area Dv of the liquefied carbon dioxide gas transfer path in the solenoid valve 5 is constant. Therefore, in the solenoid valve 5 that constitutes the carbon dioxide gas transfer path, the liquefied carbon dioxide gas does not undergo adiabatic expansion and dry ice is not produced, so blockage of the flow path can be suppressed.

[0018] Furthermore, in this embodiment, when the flow path area Dp of the liquefied carbon dioxide gas supply path L1 constituting the liquefied carbon dioxide gas transfer path is compared with the flow path area Dv of the solenoid valve 5, the flow path area Dv on the secondary side is smaller than the flow path area Dp on the primary side of the liquid transfer path. In other words, the flow path area of ​​the liquid transfer path decreases from the primary side to the secondary side. Therefore, at the connection portion between the liquefied carbon dioxide gas supply path L1 and the solenoid valve 5, the liquefied carbon dioxide gas does not adiabatically expand and dry ice is not generated, thereby suppressing blockage of the flow path.

[0019] As shown in Figures 1 and 2, the needle valve 4 is located in the liquefied carbon dioxide gas supply path L1 on the secondary side of the solenoid valve 5. The needle valve 4 functions as an orifice (a restrictor portion of the flow path, hereinafter also simply referred to as "restrictor portion") for adiabatically expanding the liquefied carbon dioxide gas to generate dry ice snow, and also as a flow rate control valve for adjusting the flow rate of the liquefied carbon dioxide gas. In this embodiment, the needle valve 4 is not particularly limited as long as it performs the function of an orifice (restrictor portion) among the above functions. As the needle valve 4, a known needle valve used for liquefied gas can be applied. An example of the configuration of the needle valve 4 will be described below.

[0020] As shown in FIG. 2, the needle valve 4 has a cylindrical internal space 4A extending in one direction, a first flow path 4a and a second flow path 4b communicating with each other via the internal space 4A, a shaft portion 4B located in the internal space 4A and slidable in the axial direction (one direction) of the internal space 4A, and a tip portion 4C located at the tip of the shaft portion 4B and inserted into the inside of the first flow path 4a from the internal space 4A side to regulate the opening area of ​​the first flow path 4a.

[0021] According to the needle valve 4, by moving the stem 4B in the axial direction of the internal space 4A and separating the tip 4C from the inside of the first flow path 4a, the opening area of ​​the first flow path 4a communicating with the internal space 4A can be increased, which means that the flow rate of the liquefied carbon dioxide gas can be increased.

[0022] In contrast, by moving the shaft portion 4B in the axial direction of the internal space 4A and inserting the tip portion 4C into the inside of the first flow path 4a, the opening area of ​​the first flow path 4a communicating with the internal space 4A can be reduced, which means that the flow rate of the liquefied carbon dioxide gas can be reduced.

[0023] In the dry ice spraying device 1 of this embodiment, it is preferable that the second flow path 4b of the needle valve 4 is connected to the liquefied carbon dioxide gas supply path L1, and the first flow path 4a of the needle valve 4 is connected to the granulation unit 3. As a result, the liquefied carbon dioxide gas supplied to the needle valve 4 from the liquefied carbon dioxide gas supply path L1 via the solenoid valve 5 is transferred from the second flow path 4b to the internal space 4A, and from the internal space 4A to the first flow path 4a, and then led to the granulation unit 3.

[0024] 2, in this embodiment, the liquefied carbon dioxide gas transfer path is composed of the second flow path 4b, the internal space 4A, and the first flow path 4a located inside the needle valve 4. In this embodiment, the flow path area of ​​the liquefied carbon dioxide gas transfer path in the needle valve 4 is the cross-sectional area of ​​the liquefied carbon dioxide gas transfer path in a direction perpendicular to the transfer direction.

[0025] In this embodiment, it is preferable that the flow path area of ​​the liquefied carbon dioxide gas supply path in the needle valve 4 is the same or decreases from the primary side to the secondary side. Specifically, in the liquefied carbon dioxide gas supply path in the needle valve 4, the flow path area of ​​the second flow path 4b located on the primary side is the largest. Next, the flow path area of ​​the internal space 4A located between the second flow path 4b and the first flow path 4a is the same as or smaller than the flow path area of ​​the second flow path 4b. Furthermore, the flow path area of ​​the first flow path 4a located on the most secondary side among these is smaller than the flow path area of ​​the internal space 4A. Therefore, in the liquefied carbon dioxide gas supply path in the needle valve 4, the liquefied carbon dioxide gas does not undergo adiabatic expansion and dry ice is not produced, thereby suppressing blockage of the flow path.

[0026] Furthermore, in this embodiment, when the flow path area Dv of the solenoid valve 5 constituting the liquefied carbon dioxide gas transfer path is compared with the flow path area of ​​the needle valve 4, the flow path area of ​​the needle valve 4 located on the secondary side is smaller than the flow path area Dv of the solenoid valve 5 located on the primary side of the liquid transfer path. In other words, the flow path area of ​​the liquid transfer path decreases from the primary side to the secondary side. Therefore, at the connection portion between the solenoid valve 5 and the needle valve 4, the liquefied carbon dioxide gas does not adiabatically expand and dry ice is not generated, thereby suppressing blockage of the flow path.

[0027] In this embodiment, the liquefied carbon dioxide gas supply path extends from the first flow path 4a located at the rearmost stage of the liquid supply path inside the needle valve 4. In other words, the first flow path 4a, whose opening area is regulated by the tip portion 4C, constitutes an orifice (throttling portion) in the liquefied carbon dioxide gas supply path.

[0028] In this embodiment, the liquefied carbon dioxide gas transfer path is configured such that the flow path area Dp of the liquefied carbon dioxide gas supply path L1, the flow path area Dv of the solenoid valve 5, and the flow path area Dc of the orifice (first flow path 4a) satisfy the relationship Dp ≧ Dv > Dc. Therefore, in this embodiment, the pressure of the liquefied carbon dioxide gas is maintained in the liquid transfer path, the liquefied carbon dioxide gas does not expand adiabatically, and dry ice is not produced, thereby preventing blockage of the flow path.

[0029] More specifically, this can be achieved by, for example, setting the flow path area of ​​the fitting of the storage container used as the liquefied carbon dioxide gas supply source 6 to φ10, setting the inner diameter of the hose used as the liquefied carbon dioxide gas supply path L1 to φ8 to 10, setting the flow path of the solenoid valve 5 to φ2 to φ6, and setting the first flow path 4a of the needle valve 4, which serves as the orifice, to φ0.5 to 1.5.

[0030] 2, the spray nozzle 2 has a spray nozzle body 2A. The spray nozzle 2 sprays dry ice snow (dry ice) generated in a granulating unit 3 (described later) from a spray port 2B of the spray nozzle body 2A.

[0031] The spray nozzle body 2A is a cylindrical member with openings at both ends. The granulating unit 3 is inserted into the spray nozzle body 2A from the base end side opposite the needle valve 4. The opening at the base end of the spray nozzle body 2A is closed by the granulating unit 3. On the other hand, the tip side of the spray nozzle body 2A, i.e., the opening at the tip, forms an injection port 2B for the dry ice snow.

[0032] When the direction in which the injection nozzle body 2A extends is defined as the axial direction, the cross-sectional shape of the injection port 2B in the direction perpendicular to the axial direction (i.e., the cross-sectional shape of the small diameter portion 2b described below) is not particularly limited as long as it is a shape that can inject dry ice snow. Examples of such cross-sectional shapes include a circle, an ellipse, an oval, a square, a rectangle, etc.

[0033] The space inside the injection nozzle 2 (i.e., the space inside the injection nozzle body 2A) has a large diameter portion 2a located at the base end, a small diameter portion 2b located at the tip end, and a connecting portion 2c located between the large diameter portion 2a and the small diameter portion 2b.

[0034] The large diameter portion 2a is a cylindrical space extending from the base end of the injection nozzle main body 2A toward the tip end. The granulation section 3 passes through the large diameter portion 2a. An opening 2C is also located in the large diameter portion 2a. At the opening 2C, the compressed gas supply path L2 is connected to the injection nozzle main body 2A (injection nozzle 2).

[0035] The small diameter portion 2b is a cylindrical space extending from the tip of the injection nozzle body 2A toward the base end. The tip 3A of the granulation portion 3 opens into the small diameter portion 2b. The tip of the small diameter portion 2b is an injection port 2B.

[0036] The connecting portion 2c is a cylindrical space whose diameter gradually decreases from the base end side to the tip end side of the injection nozzle body 2A. The large diameter portion 2a and the small diameter portion 2b communicate with each other via the connecting portion 2c.

[0037] If the direction in which the injection nozzle body 2A extends is defined as the axial direction, the cross-sectional area in the direction perpendicular to the axial direction of the small diameter portion 2b is smaller than that of the large diameter portion 2a. Also, the cross-sectional area of ​​the connecting portion 2c in the direction perpendicular to the axial direction continuously decreases from the large diameter portion 2a side toward the small diameter portion 2b side. In other words, when viewed in cross section along a plane parallel to the axial direction and including the central axis of the space inside the injection nozzle body 2A, the diameter of the cylindrical space is smaller in the small diameter portion 2b than in the large diameter portion 2a. Furthermore, when the connecting portion 2c is viewed in cross section in the same way as the large diameter portion 2a and the small diameter portion 2b, the diameter of the connecting portion 2c continuously decreases from the large diameter portion 2a side toward the small diameter portion 2b side.

[0038] The pelletizing unit 3 is a pipe that extends in one direction and is located on the secondary side of a needle valve 4 used as an orifice. The pelletizing unit 3 communicates with a liquefied carbon dioxide gas supply path L1 via the needle valve (orifice) 4. Here, the cross-sectional area Dc of the pipe that constitutes the pelletizing unit 3 in the direction perpendicular to the extension direction is larger than the flow path area Do of the first flow path 4a that constitutes the needle valve 4. That is, in the pelletizing unit 3, the liquefied carbon dioxide gas supplied via the needle valve 4 undergoes adiabatic expansion to produce dry ice.

[0039] In the dry ice spraying device 1 of this embodiment, the direction in which the granulation unit 3 extends coincides with the central axis of the spray nozzle main body 2A (they are coaxial). That is, the spray nozzle 2 and the granulation unit 3 form a double-tube structure, with the spray nozzle main body 2A as the outer tube and the granulation unit 3 as the inner tube.

[0040] The base end 3B of the pelletizing unit 3 is connected to the first flow path 4a of the needle valve 4. The tip 3A of the pelletizing unit 3 is inserted from the base end side of the injection nozzle body 2A and is positioned in the space inside the injection nozzle body 2A. In other words, the tip 3A of the pelletizing unit 3 opens into the small diameter portion 2b of the injection nozzle body 2A. As a result, in the pelletizing unit 3, the liquefied carbon dioxide gas supplied to the pelletizing unit 3 from the first flow path 4a of the needle valve 4 adiabatically expands to produce dry ice. The produced dry ice is continuously discharged from the tip 3A of the pelletizing unit 3 to the small diameter portion 2b of the injection nozzle body 2A.

[0041] The compressed gas supply path L2 is located between the compressed gas supply source 9 and the injection nozzle 2, and is a path for supplying the compressed gas derived from the compressed gas supply source 9 to the injection nozzle 2. As the compressed gas supply path L2, a pipe made of a material with low gas permeability and excellent pressure resistance can be used.

[0042] Specifically, one end of the compressed gas supply path L2 is connected to the compressed gas supply source 9, and the other end is connected to the opening 2C of the injection nozzle main body 2A. As a result, according to the dry ice injection device 1 of this embodiment, compressed gas can be supplied from the base end side of the injection nozzle 2 to the inner space (i.e., the space between the injection nozzle main body 2A and the granulation unit 3), and dry ice can be injected together with the compressed gas from the injection port 2B of the injection nozzle 2.

[0043] The compressed gas is not particularly limited, and examples of the compressed gas that can be used include inert gases such as nitrogen gas and carbon dioxide gas, and dry air obtained using an air dryer or the like.

[0044] The compressed gas supply path L2 is provided with an electromagnetic valve 7 and an adjusting valve 8. According to the dry ice spraying device 1 of this embodiment, the electromagnetic valve 7 can select whether the compressed gas supply path L2 is open or closed, and the adjusting valve 8 can adjust the amount of compressed gas supplied.

[0045] The use of the dry ice spraying device 1 of this embodiment is not particularly limited as long as it can be achieved by spraying dry ice (dry ice snow). For example, the dry ice spraying device 1 of this embodiment can be used for cooling purposes as a cooling device that sprays dry ice snow to cool an object. Furthermore, the dry ice spraying device 1 of this embodiment can be used for cleaning purposes as a cleaning device that adjusts the particle size of the dry ice and the supply amount of compressed gas to blast clean an object.

[0046] Next, a method of operating the dry ice jetting device 1 of this embodiment when used as a cleaning device will be described with reference to FIGS. In the method of operating the dry ice spraying device 1 of this embodiment, first, the solenoid valve 5 is operated to open the liquefied carbon dioxide gas supply path L1, whereby the liquefied carbon dioxide gas delivered from the liquefied carbon dioxide gas supply source 6 is supplied to the needle valve 4 via the liquefied carbon dioxide gas supply path L1.

[0047] Next, the stem 4B of the needle valve 4 is moved in the axial direction of the internal space 4A to separate the tip 4C from the inside of the first flow path 4a, thereby connecting the internal space 4A with the first flow path 4a. At this time, the flow rate of the liquefied carbon dioxide gas can be adjusted by adjusting the position of the stem 4B and adjusting the opening area of ​​the first flow path 4a.

[0048] As a result, the liquefied carbon dioxide gas supplied to the needle valve 4 from the liquefied carbon dioxide gas supply path L1 is led to the granulation section 3 via the second flow path 4b, the internal space 4A, and the first flow path 4a.

[0049] Here, inside the needle valve 4, the first flow path 4a becomes an orifice (throttling portion) from the area including the boundary between the first flow path 4a, whose opening area is regulated by the tip portion 4C, and the internal space 4A.Therefore, among the flow paths for liquefied carbon dioxide inside the needle valve 4, the liquefied carbon dioxide expands adiabatically in the first flow path 4a from the tip portion 4C onwards, making it easier for dry ice to be produced.

[0050] The temperature of the liquefied carbon dioxide gas delivered to the needle valve 4 used as an orifice is preferably adjusted to be equal to or lower than the saturation temperature at the pressure of the liquefied carbon dioxide gas being delivered. Furthermore, it is preferable that the liquefied carbon dioxide gas delivered to the needle valve 4 is not in a gas-liquid mixed state.

[0051] Next, in the granulation section 3, the liquefied carbon dioxide gas undergoes further adiabatic expansion to produce dry ice. This adjusts the particle size of the dry ice (dry ice snow) in the granulation section 3. Next, the dry ice with the adjusted particle size is led from the tip 3A of the granulation section 3 to the small diameter section 2b, which is the space inside the injection nozzle main body 2A.

[0052] The flow rate of the dry ice (dry ice snow) discharged from the tip 3A of the granulation section 3 to the small diameter section 2b can be adjusted appropriately according to the outlet area (opening area) of the injection port 2B of the injection nozzle 2. Specifically, the flow rate of the dry ice (dry ice snow) is preferably 10 to 500 g / min.

[0053] Next, the supply amount of compressed gas introduced as auxiliary gas (assist gas) into the injection nozzle 2 is adjusted. Specifically, the solenoid valve 7 is operated to open the compressed gas supply path L2, and the supply pressure of the compressed gas is adjusted by the adjustment valve 8. The supply pressure of the compressed gas is preferably adjusted to 0.2 MPaG or higher. As a result, the compressed gas delivered from the compressed gas supply source 9 is supplied at the required pressure via the compressed gas supply path L2 to the large diameter portion 2a, which is the space inside the injection nozzle main body 2A.

[0054] Next, the compressed gas introduced into the large diameter portion 2a of the injection nozzle body 2A is transferred from the base end to the tip end of the injection nozzle 2. That is, inside the injection nozzle body 2A, the compressed gas is transferred sequentially from the large diameter portion 2a to the connecting portion 2c, and from the connecting portion 2c to the small diameter portion 2b.

[0055] In the space inside the injection nozzle body 2A, the cross-sectional area in the axial direction and perpendicular to the injection nozzle body 2A is smaller in the small diameter section 2b than in the large diameter section 2a, and at the connecting section 2c, it continuously decreases from the large diameter section 2a side to the small diameter section 2b side. As a result, the flow velocity of the compressed gas introduced into the large diameter section 2a of the injection nozzle body 2A increases toward the small diameter section 2b.

[0056] Next, in the injection nozzle 2, the dry ice (dry ice snow) discharged from the tip 3A of the granulation section 3 and the compressed gas used as an assist gas join together at the small diameter section 2b inside the injection nozzle main body 2A. As a result, the dry ice is accelerated by the compressed gas and is injected from the injection port 2B of the injection nozzle 2 at the required flow rate.

[0057] The flow rate of the dry ice (dry ice snow) is adjusted by the supply pressure and flow rate of the auxiliary gas, and is preferably set to approximately 120 m / sec or more. It is also preferable that the temperature of the compressed gas be adjusted to be equal to or higher than the outside air temperature (the temperature of the environment in which the dry ice jetting device 1 is installed) before it reaches the small diameter portion 2b where it meets the dry ice.

[0058] As described above, according to the dry ice spraying device 1 of this embodiment, in the liquefied carbon dioxide gas transfer path, the flow path area Dp of the liquefied carbon dioxide gas supply path L1, the flow path area Dv of the solenoid valve 5, and the flow path area Dc of the orifice (first flow path 4a) are configured to satisfy the relationship Dp ≧ Dv > Dc. This maintains the pressure of the liquefied carbon dioxide gas in the liquid transfer path, preventing the liquefied carbon dioxide gas from adiabatically expanding midway through the flow path and preventing the generation of dry ice, thereby suppressing blockage of the flow path. Therefore, the dry ice spraying device 1 of this embodiment allows for long-term continuous operation.

[0059] Furthermore, according to the dry ice spraying device 1 of this embodiment, the solenoid valve 5 and needle valve 4 are installed immediately before the granulation section 3 in the liquefied carbon dioxide gas delivery path, thereby shortening the time lag from the start of dry ice snow spraying to the start of cleaning, and enabling stable pulse cleaning, which involves repeated spray cleaning for a relatively short period of time.

[0060] Furthermore, according to the dry ice spraying device 1 of this embodiment, the cross-sectional area of ​​the injection nozzle main body 2A constituting the injection nozzle 2 in the axial direction and perpendicular to the direction of the injection nozzle 2 is configured to continuously decrease from the base end toward the tip end. Furthermore, the tip end 3A of the pelletizing unit 3 is configured to open into the small diameter portion 2b. As a result, the flow rate of the compressed gas introduced into the injection nozzle main body 2A increases from the large diameter portion 2a toward the small diameter portion 2b, and the Venturi effect makes it easier for dry ice snow to be ejected from the tip end 3A of the pelletizing unit 3. Therefore, according to the dry ice spraying device 1 of this embodiment, it is possible to prevent the pelletizing unit 3 from being clogged with dry ice.

[0061] The technical scope of the present invention is not limited to the above-described embodiment, and includes designs within the scope of the present invention. For example, the dry ice spraying device 1 of the above-described embodiment may be configured so that a chemical agent is supplied to the space inside the spray nozzle 2 together with compressed gas. Specifically, the chemical agent is supplied to the space inside the spray nozzle main body 2A (large diameter portion 2a) together with compressed gas.

[0062] The agent is not particularly limited, but may be 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 to the compressed gas in a liquid state and adheres to the dry ice snow to freeze. The agent is preferably liquid or has a viscosity and flowability similar to that of a liquid.

[0063] According to the dry ice spraying device 1 of the above-described embodiment, the Venturi effect using compressed gas as the driving fluid allows the dry ice snow to be accelerated and at the same time a chemical agent to be applied (added) to the surface of the dry ice snow. That is, by supplying the chemical agent to the space inside the spray nozzle 2 together with the compressed gas, the chemical agent can be attached to the surface of the dry ice snow and sprayed.

[0064] In addition, although the dry ice spraying device 1 of the above-described embodiment has been described as an example of a configuration using a spray nozzle 2 with a double pipe structure, a configuration using a spray nozzle with a multiple pipe structure may also be used. For example, by using a spray nozzle with a nozzle cover on the outside of the spray nozzle body and circulating compressed gas used as assist gas in the space between the spray nozzle body and the nozzle cover, condensation on the spray nozzle caused by cooling with dry ice can be prevented.

[0065] Furthermore, in the dry ice spraying device 1 of the above-described embodiment, a configuration using a needle valve 4 as an orifice has been described as an example, but this is not limiting. As shown in Fig. 3, a configuration using an orifice member 24 having an orifice (throttling portion) 24a may be used instead of the needle valve 4. When the opening area (flow path area) Do of the orifice 24a satisfies the relationship Dp ≥ Dv > Dc, the liquefied carbon dioxide gas does not adiabatically expand in the liquid delivery path, and dry ice is not produced, thereby suppressing blockage of the flow path.

[0066] In addition, in the dry ice spraying device 1 of the above-described 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 compressed gas supply path L2. However, there is no particular limitation as long as it is possible to select the open / closed state of the flow path. For example, a manual valve may be used instead of the solenoid valve. [Explanation of symbols]

[0067] 1 dry ice blaster 2 spray nozzles 2A spray nozzle body 2B injection port 3 Granulation section 3A tip 3B Proximal end 4 needle valve 4a First flow path (orifice) 4A Interior Space 4b Second flow path 4B Shaft 4C Tip 5. Solenoid valve 24 Orifice member 24a Orifice (throttling part) L1 Liquefied carbon dioxide gas supply route L2 compressed gas supply line

Claims

1. A liquefied carbon dioxide gas supply path for supplying liquefied carbon dioxide gas from a liquefied carbon dioxide gas supply source; an orifice located in the liquefied carbon dioxide gas supply path and regulating the flow path of the liquefied carbon dioxide gas; a granulating unit located on the secondary side of the orifice and communicating with the liquefied carbon dioxide gas supply path via the orifice; a spray nozzle for spraying dry ice; A dry ice spraying device in which the flow path area of ​​the liquefied carbon dioxide gas supply path decreases from one end connected to the liquefied carbon dioxide gas supply source of the liquefied carbon dioxide gas supply path to the orifice, from the primary side to the secondary side.

2. The liquefied carbon dioxide gas supply path further includes an electromagnetic valve located on the primary side of the orifice, The dry ice spraying device according to claim 1 , wherein a flow path area of ​​the liquid supply path including the flow path inside the electromagnetic valve decreases from the primary side toward the secondary side.

3. The dry ice spraying device according to claim 1 or 2, wherein a tip of the granulating unit is located in a space inside the spray nozzle.

4. a compressed gas supply path for supplying compressed gas; the compressed gas supply path is connected to the injection nozzle; The dry ice spraying device according to claim 1 , wherein the dry ice is sprayed from the spray nozzle together with the compressed gas.

5. The dry ice spraying device according to claim 4 , wherein a chemical agent is supplied to the space inside the spray nozzle together with the compressed gas.

6. The dry ice spraying device according to claim 1 , wherein a needle valve is used as the orifice.

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