JP2019098519A - Dry ice injection device - Google Patents

Abstract

To provide a dry ice injection device capable of injecting dry ice particles at a stable flow rate even if the flow rate of injected dry ice particles is extremely small.SOLUTION: A dry ice injection device comprises: a liquefied carbon dioxide supply path 6 for supplying liquefied carbon dioxide; a carrier gas supply path 7 for supplying a carrier gas; an ejection hole 16 for ejecting the liquefied carbon dioxide supplied from the liquefied carbon dioxide supply path 6; an expansion space 10a for expanding the liquefied carbon dioxide ejected from the ejection holes 16 to produce dry ice particles; a merging space 11 for merging the carrier gas supplied from the carrier gas supply path 7 with the dry ice particles produced in the expansion space 10a; and an injection path 18 formed from the merging space 11 to the injection port 17. A gas-liquid separator 15 is provided in the middle of the liquefied carbon dioxide supply path 6, and the flow path length of the liquefied carbon dioxide supply path 6 from a downstream end of the gas-liquid separator 15 to the ejection hole 16 is 200 mm or less.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a dry ice jetting apparatus that cleans the surface of a target by jetting dry ice particles toward the target.

  Conventionally, an apparatus is known which injects dry ice particles generated by adiabatically expanding liquefied carbon dioxide into a carrier gas flow (see, for example, Patent Document 1).

  In the apparatus disclosed in Patent Document 1, liquefied carbon dioxide supplied from a liquefied carbon dioxide gas container to a dry ice jet nozzle is inside a dry ice generating pipe (referred to as "dry ice supply pipe" in the same document). Adiabatically expand at this point to produce dry ice, and use the produced dry ice as a flow of carrier gas (referred to as "acceleration gas" in the same document) supplied from the liquid nitrogen storage tank to the dry ice jet nozzle. Introduce and inject.

Unexamined-Japanese-Patent No. 2003-145429

  By the way, in this type of apparatus which performs processing (washing etc.) of the surface of the object by jetting dry ice particles toward the object, the flow rate of the dry ice particles to be jetted is usually a flow rate suitable for the object . For example, if the object is a delicate item that is weak to impact, such as an electronic component, dry ice particles must be jetted at a very low flow rate.

  However, in the conventional apparatus for injecting dry ice particles, when the flow rate of the dry ice particles to be injected is extremely reduced, it becomes impossible to inject the dry ice particles at a stable flow rate. That is, when the flow rate of the dry ice particles to be injected is extremely reduced, the influence of carbon dioxide gas vaporized by heat penetration in the piping before adiabatic expansion becomes large, and dry ice particles are intermittently generated in the dry ice formation pipe It will be. As a result, the state in which dry ice particles are injected from the injection port and the state in which only the carrier gas containing no dry ice particles is injected are alternately repeated to uniformly process (clean, etc.) the surface of the object. It will not be possible.

  The present invention has been made in view of the above problems, and provides a dry ice jetting device capable of jetting dry ice particles at a stable flow rate even if the flow rate of the dry ice particles to be jetted is extremely small. With the goal.

  A dry ice injection device according to one aspect of the present invention comprises a liquefied carbon dioxide supply passage for supplying liquefied carbon dioxide, a carrier gas supply passage for supplying a carrier gas, and liquefied carbon dioxide supplied from the liquefied carbon dioxide supply passage. And an expansion space for expanding the liquefied carbon dioxide ejected from the injection hole to generate dry ice particles, a carrier gas supplied from the carrier gas supply path, and an expansion space And a jet passage formed from the merge space to the injection port. And, a gas-liquid separator is provided in the middle of the liquefied carbon dioxide supply passage, and the flow passage length of the liquefied carbon dioxide supply passage from the downstream end of the gas-liquid separator to the jet hole is 200 mm or less. It is characterized by

  The dry ice jetting apparatus having the above configuration may include a discharge path for discharging the gas accumulated in the upper part in the gas-liquid separator to the outside, and a valve for opening and closing the discharge path.

  In the dry ice jetting apparatus having the above configuration, preferably, the liquefied carbon dioxide supply path downstream of the gas-liquid separator is formed in the vertical direction.

  In the dry ice injection device having the above configuration, it is preferable that an on-off valve is provided midway in the liquefied carbon dioxide supply path downstream of the gas-liquid separator, and the on-off valve is a ball valve.

  The dry ice injection apparatus having the above configuration includes a dry ice generating pipe whose inside is the expansion space, and the carrier gas supply path is formed to supply the carrier gas toward the dry ice generating pipe. The dry ice generating pipe is an inner pipe that internally expands liquefied carbon dioxide ejected from the ejection holes to generate dry ice particles, and an outer pipe provided outside the inner pipe with a gap. Preferably, it comprises a tube.

  A dry ice injection device according to another aspect of the present invention comprises a liquefied carbon dioxide reservoir storing liquefied carbon dioxide at a pressure of 2 Mpa ± 0.2 Mpa or less, and liquefied carbon dioxide at the pressure from the liquefied carbon dioxide reservoir. A liquefied carbon dioxide supply passage for supplying carbon dioxide, a carrier gas supply passage for supplying a carrier gas, an ejection hole for ejecting liquefied carbon dioxide supplied from the liquefied carbon dioxide supply passage, and liquefied carbon dioxide ejected from the ejection hole An expansion space for expanding carbon to generate dry ice particles, a merging space for merging carrier gas supplied from the carrier gas supply path, and dry ice particles generated in the expansion space, and the merging space And an injection path formed up to the injection port. And, a gas-liquid separator is provided in the middle of the liquefied carbon dioxide supply passage, and the flow passage length of the liquefied carbon dioxide supply passage from the downstream end of the gas-liquid separator to the jet hole is 400 mm or less. It is characterized by

  The dry ice injection device having the above configuration includes the dry ice supply pipe having the expansion space inside and supplying the dry ice particles generated in the expansion space toward the merging space, the dry ice At least a portion of the supply pipe may be configured using a flexible tube, and at least a portion of the carrier gas supply path may also be configured using a flexible tube.

  According to the dry ice injection device of the present invention, even if the flow rate of dry ice particles to be injected is extremely small, the dry ice particles can be injected at a stable flow rate.

It is a fragmentary sectional view showing an important section of a dry ice injection device concerning a 1st embodiment. It is an air piping systematic diagram of the whole dry ice injection device concerning a 1st embodiment. It is an air piping system diagram of the dry ice injection device concerning the modification of a 1st embodiment. However, illustration of the carrier gas supply unit is omitted. It is a systematic diagram of piping etc. of the whole dry ice injection device concerning a 2nd embodiment. It is a schematic cross section which shows the orifice board which concerns on 2nd Embodiment, and its vicinity.

  Hereinafter, a dry ice injection device according to a first embodiment of the present invention will be described with reference to the drawings. As shown in FIGS. 1 and 2, the dry ice injection device 1 includes an injection device main body 2, a liquefied carbon dioxide supply unit 3, a carrier gas supply unit 4, a control panel 5 and the like.

  As shown in FIG. 1, the injection device main body 2 includes a merging member 8, a nozzle 9, a dry ice production pipe 10 and the like.

  The merging member 8 internally includes a merging space 11 in which the carrier gas supplied through the carrier gas supply path 7 and the dry ice particles flowing out from the dry ice generating tube 10 described later merge. In the present embodiment, dry air is used as a carrier gas. As the carrier gas, a gas having a low dew point temperature can be used, and in addition to the above-described dry air, a nitrogen gas, a carbon dioxide gas, or the like may be used.

  Further, as shown in FIG. 1, a dry ice generating pipe 10 formed of a double pipe is provided in the merging member 8. The dry ice generating tube 10 is connected at its base end to the liquefied carbon dioxide supply path 6 via the orifice plate 13.

  The orifice plate 13 is a thin plate (e.g., plate thickness) in which one or a plurality of ejection holes 16 (in this embodiment, two or more ejection holes 16 with an inner diameter of 0.1 mm to 0.2 mm are formed) are formed. 1 mm disc). The orifice plate 13 is provided at the boundary between the downstream end of the liquefied carbon dioxide supply path 6 and the dry ice production pipe 10.

  The ejection holes 16 formed in the orifice plate 13 eject the liquefied carbon dioxide supplied from the liquefied carbon dioxide supply path 6. The liquefied carbon dioxide is low temperature liquefied carbon dioxide.

  The dry ice production pipe 10 includes an inner pipe 101 and an outer pipe 102 provided on the outer side of the inner pipe 101 with a gap. The tip end portion 101 a of the inner pipe 101 is located on the tip end side of a predetermined length from the tip end portion 102 a of the outer pipe 102. In the present embodiment, the proximal end portion of the outer pipe 102 is fixed to the outer peripheral surface of the inner pipe 101.

  The inside of the inner pipe 101 of the dry ice generating pipe 10 functions as an expansion space 10a. Also, the cross-sectional area of the upstream portion in the dry ice forming tube 10 is an orifice so that liquefied carbon dioxide ejected from the ejection holes 16 of the orifice plate 13 into the expansion space 10a is adiabatically expanded to form hard dry ice particles. The cross-sectional area of the ejection holes 16 formed in the plate 13 is set to be somewhat large.

  The liquefied carbon dioxide supply unit 3 includes, as shown in FIG. 2, a liquefied carbon dioxide supply passage 6, a liquefied carbon dioxide storage unit 14, a gas-liquid separator 15, and the like. In addition, as liquefied carbon dioxide storage part 14, a cryogenic container (LGC), a storage tank (CE: cold evaporator) etc. are used, for example.

  The liquefied carbon dioxide supply passage 6 is formed by piping and the like from the liquefied carbon dioxide storage unit 14 to the ejection holes 16 formed in the orifice plate 13, and the liquefied carbon dioxide is expanded in the expansion space 10 a in the dry ice generating tube 10. Supply to On the liquefied carbon dioxide supply passage 6, the on-off valve 19, the filter 20, the pressure gauge P1, the safety valve 21, the on-off valve SV1, the gas-liquid separator 15, which are attached to the liquefied carbon dioxide storage 14 sequentially from the upstream side A ball valve CV1 is provided.

  The gas-liquid separator 15 is provided at a position close to the injection device main body 2 (orifice plate 13). In the present embodiment, the gas-liquid separator 15 includes a container 15a, a gas discharge passage 15b, and a liquid level adjustment valve SV4 that opens and closes the gas discharge passage 15b.

  The upper side of the vessel 15a of the gas-liquid separator 15 is connected to the upstream side of the liquefied carbon dioxide supply path 6, from which liquefied carbon dioxide is supplied into the vessel 15a. The downstream side of the liquefied carbon dioxide supply passage 6 is connected to the bottom of the vessel 15a, and liquefied carbon dioxide from which the gas has been removed flows out of the vessel 15a to the downstream side of the liquefied carbon dioxide supply passage 6. In the present embodiment, the volume of the container 15a is, for example, in the range of 0.1 L to 1.5 L, and the length of the liquefied carbon dioxide supply passage 6 from the downstream end of the container 15a to the ejection hole 16 is , 200 mm or less (preferably 100 mm or less, more preferably 50 mm or less). The liquefied carbon dioxide supply passage 6a provided downstream of the gas-liquid separator 15 is formed in the vertical direction including the flow passage in the ball valve CV1.

  The gas discharge passage 15 b is provided to discharge the carbon dioxide gas accumulated in the upper part of the container 15 a to the outside. The liquid level adjustment valve SV4 is provided to adjust the liquid level in the container 15a. Specifically, when the liquid level in the container 15a is not high, the liquid level adjustment valve SV4 repeats the opening / closing operation of the gas discharge path 15b at predetermined intervals (for example, every 10 seconds). When the liquid level rises and liquefied carbon dioxide flows out from the gas discharge passage 15b, a drop in fluid temperature is detected by the temperature detector T3 provided in the gas discharge passage 15b, and the control panel 5 detects the liquid surface The closing time of the gas discharge passage 15b of the adjusting valve SV4 is set to be longer than the opening time. After that, when the temperature of the fluid from which the liquefied carbon dioxide flows out from the gas discharge passage 15b rises to a predetermined value by the temperature detector T3, the control panel 5 causes the liquid level adjustment valve SV4 to once again generate a predetermined time interval (for example 10 Control is performed so as to repeat the opening / closing operation of the gas discharge passage 15b every second).

  The carrier gas supply passage 7 is configured of an internal carrier gas supply passage 7 a formed inside the merging member 8 and an external carrier gas supply passage 7 b formed outside the merging member 8.

  The internal carrier gas supply passage 7 a is formed to supply the carrier gas toward the dry ice generating tube 10. In the present embodiment, the internal carrier gas supply passage 7a forms a linear flow passage, and supplies the carrier gas at a predetermined acute angle toward the straight dry ice tube 10. In other words, the angle of the center line of the internal carrier gas supply passage 7a with respect to the center line of the dry ice generating tube 10 is a predetermined acute angle (30 ° in the example of FIG. 2). The angle between the center lines is preferably a predetermined acute angle, but may be approximately 90 ° or a predetermined obtuse angle.

  In the merging space 11, the carrier gas supplied from the carrier gas supply path 7 and the dry ice particles generated in the inner pipe 101 of the dry ice generating pipe 10 merge. The injection path 18 is formed in the nozzle 9 from the merging space 11 to the injection port 17 at the tip of the nozzle 9 of the jetting device main body 2, and the dry ice particles merged with the carrier gas in the merging space 11 are the carrier gas The acceleration is carried on the flow of the air from the injection port 17 toward the object.

  The external carrier gas supply passage 7 b is formed from the air pressure source 22 to the joining member 8, and is configured to supply the carrier gas into the joining member 8 of the injection device main body 2. As shown in FIG. 2, on the external carrier gas supply passage 7b, the filter 23, the pressure reducing valve RV1, the on-off valve SV2, the flow switch 24, the pressure detector P2, the temperature detector T1 before the heater, in order from the upstream side. A heater 25 for raising the temperature of the carrier gas, a temperature detector T2 after the heater, and the like are provided.

  Immediately after the filter 23, a branch passage 26 for supplying operating air to the ball valve CV1, which is an air-operated valve, is formed. A pressure reducing valve RV2 and an on-off valve SV3 are provided on the branch passage 26.

  The control panel 5 has a ball valve CV1 and open / close valves SV1 to SV3 based on various information input from temperature detectors T1 to T3, flow switch 24, pressure detectors P1 and P2, etc., and various operation instructions from the user. And, opening and closing control of the liquid level adjustment valve SV4 and temperature control of the heater 25 are performed.

  In the dry ice injection device 1 having the above configuration, when the on-off valve 19 is opened and a predetermined operation for starting operation is performed in the control panel 5, liquefied carbon dioxide is an orifice through the liquefied carbon dioxide supply path 6. The liquid carbon dioxide is sent to the jet holes 16 of the plate 13, and the liquefied carbon dioxide is jetted from the jet holes 16 to the expansion space 10 a in the inner pipe 101 of the dry ice production pipe 10. And liquefied carbon dioxide adiabatically expands in expansion space 10a, and becomes dry ice particles. At the same time, the carrier gas heated to a predetermined temperature by the heater 25 is supplied toward the outer tube 102 of the dry ice production pipe 10 through the carrier gas supply path 7 and is injected from the injection port 17 through the injection path 18. Be done. The dry ice particles flowing out from the inner pipe 101 of the dry ice generating pipe 10 are mixed in the carrier gas flowing toward the injection port 17 in the merging space 11, and are accelerated in the injection path 18 on the carrier gas flow. After that, the fuel is injected from the injection port 17 toward the object X.

  According to the dry ice jetting device 1 described above, the following effects are achieved.

(1) Vaporized carbon dioxide gas is removed by the gas-liquid separator 15 provided in the middle of the liquefied carbon dioxide supply passage 6. Moreover, since the flow path length of the liquefied carbon dioxide supply path 6 from the downstream end of the gas-liquid separator 15 to the ejection port 16 is extremely short (200 mm or less), the liquefied carbon dioxide supplied to the ejection port 16 There is almost no carbon dioxide gas vaporized to carbon. For this reason, dry ice particles are continuously generated in the dry ice production pipe 10, and even if the flow rate of the dry ice particles to be jetted is extremely small, the dry ice particles are jetted from the injection port 17 at a stable flow rate. Is possible.
(2) Since the liquefied carbon dioxide supply passage 6 on the downstream side of the gas-liquid separator 15 is formed in the vertical direction, heat permeation in the liquefied carbon dioxide supply passage 6 on the downstream side of the gas-liquid separator 15 Even if carbon dioxide gas is generated, the generated carbon dioxide gas floats upward and is captured by the gas-liquid separator 15. As a result, the generated carbon dioxide gas is prevented from flowing into the injection holes 16, and it becomes possible to inject the dry ice particles at a more stable flow rate.
(3) Since the on-off valve CV1 provided in the middle of the liquefied carbon dioxide supply path 6 downstream of the gas-liquid separator 15 is a ball valve, air bubbles are generated in the valve by heat intrusion from the outside of the valve However, the air bubbles do not easily stay in the valve. When air bubbles stay in the valve, the possibility that the air bubbles gradually grow grow and flow into the ejection holes 16 is increased, but such problems are less likely to occur by employing the ball valve.
(4) In the dry ice jetting apparatus of the type in which the carrier gas is sprayed to the dry ice producing pipe 10 as in the dry ice jetting apparatus disclosed in Patent Document 1, the dry ice producing pipe 10 is warmed by the carrier gas Because of this, the hardness of the dry ice particles flowing in the dry ice forming tube 10 is reduced, and the effect of cleaning the surface of the object is reduced. Furthermore, when the flow rate of the liquefied carbon dioxide ejected from the ejection holes 16 is extremely small, the dry ice forming tube 10 is further easily warmed, and the hardness of the dry ice particles may be further reduced. However, according to the present embodiment, since the dry ice generating pipe 10 has a double pipe structure, the carrier gas supplied from the carrier gas supply path 7 directly contacts the inner pipe 101 covered with the outer pipe 102. In addition, since a gap functioning as a heat insulating layer is interposed between the outer pipe 102 and the inner pipe 101, hard dry ice particles are easily generated in the inner pipe 101 of the dry ice generating pipe 10. .
(5) In the present embodiment, since the opening / closing control of the gas discharge passage 15b is performed based on the temperature of the fluid flowing through the gas discharge passage 15b, the liquid level adjustment in the gas-liquid separator 15 is performed, The liquid level height in the gas-liquid separator 15 can be adjusted with a simple and inexpensive configuration.

  The modification of this embodiment is mentioned below.

  In this embodiment, although the number of injection device bodies 2 provided in the dry ice injection device 1 is one, in order to expand the injection range of the dry ice particles, as shown in FIG. It may be a plurality. In this case, a branched passage 28 is provided between the ball valve CV1 and the orifice plate 13 to supply liquefied carbon dioxide to the added injection device main body 2. Although the carrier gas supply unit 4 is not shown in FIG. 3, the carrier gas is supplied from the carrier gas supply unit 4 to each injection device main body 2.

  In the present embodiment, the ball valve CV1 is provided on the downstream side of the gas-liquid separator 15, but it is also possible to apply another type of valve instead of the ball valve CV1. That is, even if other types of valves are applied, the effect by installing the gas-liquid separator 15 can be obtained.

  Hereinafter, a dry ice injection device according to a second embodiment of the present invention will be described with reference to FIG. The dry ice jetting apparatus 201 according to the second embodiment has a configuration capable of jetting dry ice particles while the nozzle 209 and the like move relative to the object X.

  The dry ice injection device 201 according to the second embodiment includes an injection device main body 202, a liquefied carbon dioxide supply unit 203, a carrier gas supply unit 204, a control panel 205, a housing 300, and the like.

  The injection device main body 202 includes a merging member 208, a nozzle 209, a dry ice supply pipe 210, and the like.

  The merging member 208 internally includes a merging space 211 in which the carrier gas supplied through the carrier gas supply path 207 and the dry ice particles supplied from the dry ice supply pipe 210 merge. The injection path 218 is formed in the nozzle 209 from the junction space 211 to the injection port 217 at the tip of the nozzle 209, and dry ice particles joined with the carrier gas in the junction space 211 are accelerated by the flow of the carrier gas. Then, the fuel is injected from the injection port 217 toward the object X. As the carrier gas supplied through the carrier gas supply path 207, the same carrier gas as that in the first embodiment can be used.

  The dry ice supply pipe 210 is connected at its base end to the liquefied carbon dioxide supply path 206 via the orifice plate 213. In this embodiment, a part of the dry ice supply pipe 210 is configured using a flexible tube so that the merging member 208 and the nozzle 209 can move relative to the object X. For example, a Teflon (registered trademark) tube can be used as the flexible tube. The joining member 208 and the nozzle 209 are used, for example, by being attached to a nozzle moving device that moves relative to the surface of the object X. A robot arm and an XY stage can be exemplified as the nozzle moving device.

  The orifice plate 213 is formed of, for example, a thin plate in which one or more ejection holes 216 (in this embodiment, the ejection holes 216 having an inner diameter of 0.1 mm to 0.6 mm are formed at one position). ing. The orifice plate 213 is provided at the boundary between the downstream end of the liquefied carbon dioxide supply path 206 and the dry ice supply pipe 210, as shown in FIG.

  The ejection holes 216 formed in the orifice plate 213 eject the liquefied carbon dioxide supplied from the liquefied carbon dioxide supply path 206 at a pressure of 2 MPa ± 0.2 MPa or less. The three arrows in FIG. 5 indicate the direction in which the liquefied carbon dioxide is ejected from the ejection holes 216.

  The inside of the dry ice supply pipe 210 functions as an expansion space 210a. Further, the cross-sectional area of the upstream portion in the dry ice supply pipe 210 is an orifice so that the liquefied carbon dioxide ejected from the ejection holes 216 of the orifice plate 213 into the expansion space 210a is adiabatically expanded to form hard dry ice particles. The cross-sectional area of the ejection holes 216 formed in the plate 213 is set to be somewhat large.

  As shown in FIG. 4, the liquefied carbon dioxide supply unit 203 includes a liquefied carbon dioxide supply path 206, a liquefied carbon dioxide storage unit 214, a gas-liquid separator 215, and the like.

  The liquefied carbon dioxide storage unit 214 is a low pressure storage unit that stores liquefied carbon dioxide at a low pressure of 2 MPa ± 0.2 MPa or less. Low temperature liquefied carbon dioxide is supplied from the liquefied carbon dioxide storage unit 214 to the liquefied carbon dioxide supply path 206 at a pressure of 2 MPa ± 0.2 MPa or less. As the liquefied carbon dioxide storage unit 214, for example, a cryogenic container (LGC), a storage tank (CE: cold evaporator) or the like is used.

  The liquefied carbon dioxide supply passage 206 is formed by piping or the like from the liquefied carbon dioxide storage unit 214 to the ejection holes 216 formed in the orifice plate 213. On the liquefied carbon dioxide supply passage 206, a safety valve 221, a strainer 222, an on-off valve CV2, a pressure sensor P3, a gas-liquid separator 215, and an on-off valve CV3 are provided in this order from the upstream side.

  The gas-liquid separator 215 is provided at a position close to the orifice plate 213. In the present embodiment, the gas-liquid separator 215 includes a container 215a, a gas discharge passage 215b, a liquid level adjustment valve CV4 that opens and closes the gas discharge passage 215b, and a flow rate adjustment valve 225.

  The upstream side 206 a of the liquefied carbon dioxide supply path 206 is connected to the upper portion of the vessel 215 a of the gas-liquid separator 215, and liquefied carbon dioxide is supplied from here into the vessel 215 a. The downstream side 206b of the liquefied carbon dioxide supply passage 206 is connected to the bottom of the vessel 215a, and liquefied carbon dioxide from which the gas is removed flows out of the vessel 215a to the downstream side 206b of the liquefied carbon dioxide supply passage 6 . In the present embodiment, the volume of the container 215a is, for example, in the range of 0.1 L or more and 1.5 L or less, and the flow path length of the liquefied carbon dioxide supply passage 206 from the downstream end of the container 215a to the ejection hole 216 is , 400 mm or less (preferably 200 mm or less, more preferably 100 mm or less).

  The gas discharge passage 215b is provided to discharge the carbon dioxide gas accumulated at the top of the container 215a. The liquid level adjustment valve CV4 is provided to adjust the liquid level in the container 215a. Specifically, when the liquid level in the container 215a is not high, the liquid level adjustment valve CV4 repeats the open / close operation of the gas discharge path 215b at regular intervals (for example, every 10 seconds). When the liquid level rises and liquefied carbon dioxide flows from the container 215a into the gas discharge passage 215b, a drop in fluid temperature is detected by the temperature detector T4 provided in the gas discharge passage 215b, and the control panel 205 The closing time of the gas discharge passage 215b of the liquid level adjustment valve CV4 is set to be longer than the opening time. After that, when the temperature of the fluid flowing through the gas discharge passage 215b rises to a predetermined value by the temperature detector T4, the control panel 205 again discharges the gas at every predetermined time (for example, every 10 seconds). Control is performed to repeat the opening and closing operation of the path 215b.

  In addition, a helical pipe having a relatively small inner diameter is used for part of the gas discharge passage 215b. By this piping, a pressure loss is given to the gas discharge path 215b, and the pressure fluctuation in the container 215a is suppressed. As a result, the flow rate of the liquefied carbon dioxide ejected from the ejection holes 216 to the expansion space 210a is stabilized, and the flow rate of the dry ice particles ejected from the nozzle 209 to the object X is also stabilized. In the present embodiment, the pressure (about 2 MPa in the present embodiment) at which liquefied carbon dioxide is ejected from the ejection holes 216 and the supply pressure of the carrier gas supplied to the merging space 211 (about 0.3 MPa in the present embodiment) In order to stabilize the flow rate of the dry ice particles jetted from the nozzle 209 to the object X, it is preferable to suppress the pressure fluctuation in the container 215a.

  The carrier gas supply path 207 is formed from the air pressure source 223 to the merging space 211 in the merging member 208. As shown in FIG. 4, on the carrier gas supply path 207, in order from the upstream side, the pressure reducing valve RV3, the pressure gauge PG, the flow rate adjusting valve 224, the flow switch 226, the on-off valve SV6, the pressure detector P4, the heater A temperature detector T5, a heater 227 for raising the temperature of the carrier gas, a temperature detector T6 after the heater, and the like are provided. In the present embodiment, the air pressure source 223 is constituted by a compressor, and the original pressure supplied from the compressor is reduced to a first predetermined pressure by the pressure reducing valve RV3 and supplied into the merging member 208 by the carrier gas supply passage 207. The flow control valve 224 throttles the flow rate so that the pressure becomes a second predetermined pressure. In the present embodiment, the second predetermined pressure is within 0.3 MPa 0.1 MPa.

  In the present embodiment, a part of the portion of the carrier gas supply passage 207 which is out of the case 300 is configured using a flexible tube so that the merging member 208 and the nozzle 209 can move relative to the object X. ing. A branch path 228 for supplying operating air to the air operated valve is formed immediately after the pressure reducing valve RV3. In the present embodiment, a ball valve of an air operated valve is used as the open / close valve CV2, the open / close valve CV3, and the liquid level adjustment valve CV4.

  The control panel 205 controls the on-off valves CV2, CV3 and SV6 and the liquid based on various information input from the temperature detectors T4 to T6, the flow switch 226, the pressure detectors P3 and P4, etc., and various operation instructions from the user. The opening and closing control of the surface adjustment valve CV4 and the temperature control of the heater 227 are performed.

  In the housing 300, at least a portion from the middle portion 206P1 to the downstream end portion 206P2 of the liquefied carbon dioxide supply path 206, a gas-liquid separator 215, and a control panel 205 are installed. In the present embodiment, an intermediate portion (from the middle portion 207P1 to the middle portion 207P2) of the carrier gas supply path 207 is further provided in the housing 300. In addition, a pipe joint 228 is provided in the middle portion 206P1 and the downstream end portion 206P2 of the liquefied carbon dioxide supply path 206. In addition, a pipe joint 228 is provided in the middle portions 206P1 and 206P2 of the carrier gas supply path 207. Also, a pipe joint 228 is provided at the downstream end of the gas discharge passage 215b. Each pipe joint 228 is exposed from the housing 300, so that connection work such as piping can be easily performed from the outside of the housing 300.

  In the dry ice jetting apparatus 201 having the above configuration, when the control panel 205 performs a predetermined operation for starting operation, liquefied carbon dioxide is fed to the ejection holes 216 of the orifice plate 213 through the liquefied carbon dioxide supply path 206. Be liquid. The liquefied carbon dioxide is ejected from the ejection holes 216 into the expansion space 210 a in the dry ice supply pipe 210. And liquefied carbon dioxide adiabatically expands in the expansion space 210a, and becomes dry ice particles. At the same time, the carrier gas heated to a predetermined temperature by the heater 227 is supplied into the merging member 208 through the carrier gas supply path 207. The carrier gas supplied to the merging member 208 merges with the dry ice particles flowing out from the downstream side of the dry ice supply pipe 210, and is then jetted from the injection port 217 toward the object X.

  According to the dry ice jet apparatus 201 described above, the following effects are achieved.

(1) Vaporized carbon dioxide gas is removed by the gas-liquid separator 215 provided in the middle of the liquefied carbon dioxide supply path 206. Moreover, since the flow path length of the liquefied carbon dioxide supply path 206 from the downstream end of the gas-liquid separator 215 to the ejection hole 216 is extremely short (400 mm or less), the liquefied carbon dioxide supplied to the ejection hole 216 There is almost no carbon dioxide gas vaporized to carbon. Therefore, dry ice particles are continuously generated in the dry ice supply pipe 210, and even if the flow rate of the dry ice particles to be injected is extremely small, the dry ice particles are injected from the injection port 217 at a stable flow rate. Is possible. In particular, when a low pressure liquefied carbon dioxide storage unit 214 such as LGC or CE is adopted, the influence of heat intrusion on liquefied carbon dioxide flowing through piping becomes large, but from the downstream end of the gas-liquid separator 215 to the ejection hole 216 Since the flow path length of the liquefied carbon dioxide supply path 206 is extremely short, the influence of heat penetration can be almost eliminated, and it becomes possible to jet dry ice particles at a stable flow rate.
(2) Also, even when using a low pressure and large volume carbon dioxide reservoir 214 such as LCG, CE, etc., dry ice particles can be jetted at a very small flow rate and a stable flow rate. It becomes possible to carry out continuous cleaning for a long time on a weak delicate object X.

DESCRIPTION OF SYMBOLS 1 dry ice injection apparatus 6 liquefied carbon dioxide supply path 7 carrier gas supply path 10 dry ice production pipe 101 inner pipe 102 outer pipe 10 a expansion space 11 merging space 15 gas-liquid separator 15 b discharge path 16 injection hole 17 injection port 18 injection path 214 Liquefied Carbon Dioxide Reservoir 206 Liquefied Carbon Dioxide Supply Path 207 Carrier Gas Supply Path 210 Dry Ice Supply Pipe 210a Expansion Space 211 Confluence Space 215 Gas-Liquid Separator 216 Jet Hole 217 Injection Port 218 Injection Path CV1 Ball Valve SV4 Open or Close Discharge Path On-off valve

Claims (7)

A liquefied carbon dioxide supply path for supplying liquefied carbon dioxide;
A carrier gas supply path for supplying a carrier gas,
An ejection hole for ejecting liquefied carbon dioxide supplied from the liquefied carbon dioxide supply path;
An expansion space for expanding the liquefied carbon dioxide ejected from the ejection holes to generate dry ice particles;
A merging space in which the carrier gas supplied from the carrier gas supply path and the dry ice particles generated in the expansion space are merged;
An injection path formed from the merging space to the injection port;
A dry ice injection device comprising
A gas-liquid separator is provided in the middle of the liquefied carbon dioxide supply passage, and the flow passage length of the liquefied carbon dioxide supply passage from the downstream end of the gas-liquid separator to the ejection port is 200 mm or less. Dry ice injection device. In the dry ice injection device according to claim 1,
A discharge path for discharging the gas accumulated in the upper part in the gas-liquid separator to the outside;
A valve for opening and closing the discharge passage;
A dry ice injection device comprising: In the dry ice injection device according to claim 1 or 2,
The liquefied carbon dioxide supply passage downstream of the gas-liquid separator is formed in the vertical direction.
An apparatus for injecting dry ice characterized by In the dry ice jet apparatus according to any one of claims 1 to 3.
An on-off valve is provided in the middle of the liquefied carbon dioxide supply passage downstream of the gas-liquid separator, and the on-off valve is a ball valve.
An apparatus for injecting dry ice characterized by In the dry ice jet apparatus according to any one of claims 1 to 4.
It is equipped with a dry ice production tube whose inside is the expansion space,
The carrier gas supply passage is formed to supply the carrier gas toward the dry ice generating pipe,
The dry ice generating pipe includes an inner pipe which internally expands liquefied carbon dioxide ejected from the ejection holes to generate dry ice particles, and an outer pipe provided outside the inner pipe with a gap. Including
A dry ice injection device characterized by A liquefied carbon dioxide reservoir that stores liquefied carbon dioxide at a pressure of 2 Mpa ± 0.2 Mpa or less,
A liquefied carbon dioxide supply path for supplying liquefied carbon dioxide at the pressure from the liquefied carbon dioxide storage unit;
A carrier gas supply path for supplying a carrier gas,
An ejection hole for ejecting liquefied carbon dioxide supplied from the liquefied carbon dioxide supply path;
An expansion space for expanding the liquefied carbon dioxide ejected from the ejection holes to generate dry ice particles;
A merging space in which the carrier gas supplied from the carrier gas supply path and the dry ice particles generated in the expansion space are merged;
An injection path formed from the merging space to the injection port;
A dry ice injection device comprising
A gas-liquid separator is provided in the middle of the liquefied carbon dioxide supply path, and the flow path length of the liquefied carbon dioxide supply path from the downstream end of the gas-liquid separator to the ejection port is 400 mm or less. Dry ice injection device. In the dry ice injection device according to claim 6,
It has the said expansion space inside, and the dry ice supply pipe which supplies the dry ice particle | grains produced | generated in the said expansion space to the said confluence space is provided,
At least a portion of the dry ice supply tube is configured using a flexible tube,
At least one part of the said carrier gas supply path is also comprised using a flexible tube, The dry ice injection apparatus characterized by the above-mentioned.

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