JP2011038581A - Liquefied gas injecting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquefied gas injecting device capable of effectively injecting low temperature liquified gas in a liquid state to an object to be cooled. <P>SOLUTION: The liquefied gas injecting device includes a cylindrical heat insulating storage tank 11, a cooling tank 12 disposed in the heat insulating storage tank 11, an injection nozzle 13 provided in a bottom of the heat insulating storage tank, a needle 14 for opening and closing the injection nozzle, a seal gas injection part 15 surrounding the injection nozzle, an injection liquid nitrogen supply pipe 16 for supplying injection liquid nitrogen with a pressure exceeding the atmosphere pressure into the heat insulating storage tank, a cooling liquid nitrogen supply pipe 17 for supplying cooling liquid nitrogen in the saturated state at the atmosphere pressure or lower into the cooling tank, a nitrogen gas discharge pipe 18 for discharging the nitrogen gas vaporized in the cooling tank to the outside, a seal gas supply pipe 19 for supplying the seal gas to the seal gas injection part, and a needle driving device 20 for opening and closing the needle 14. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a liquefied gas injection apparatus, and more particularly to an apparatus for injecting a low-temperature liquefied gas such as liquid nitrogen.

  In order to inject a low-temperature liquefied gas, for example liquid nitrogen, into a predetermined area, a predetermined pressure is required, but the low-temperature liquefied gas is accompanied by flash evaporation when injected into the atmosphere from a high pressure state. Part of it gasifies. Also, stable control is difficult due to pulsation due to gasification immediately before the nozzle. As a countermeasure, it is known to supply a supercooled liquefied gas (for example, see Patent Document 1).

  On the other hand, when the on-off valve is outside the liquefied gas, there is a problem that the temperature of the liquefied gas after supercooling rises or gasifies due to heat intrusion. A valve structure for suppressing temperature rise or gasification is known (for example, see Patent Document 2).

Japanese Patent Publication No. 6-88574 Japanese Patent Laid-Open No. 11-294696

  However, the one described in Patent Document 1 has a complicated structure and requires a large amount of low-temperature liquefied gas, and cannot be used for jetting liquefied gas. Moreover, in what was described in patent document 2, since it aimed at injecting low temperature liquefied gas in the mist form of a gas-liquid mixture state, even if a part of low temperature liquefied gas which came out of the nozzle vaporizes, it is a problem. However, it has been difficult to apply to a use in which a low-temperature liquefied gas is injected into an object to be cooled as a liquid.

  Accordingly, an object of the present invention is to provide a liquefied gas injection device capable of efficiently injecting a low-temperature liquefied gas into a cooled object in a liquid state.

  In order to achieve the above object, a liquefied gas injection device according to the present invention includes an adiabatic storage tank that stores liquefied gas at an injection pressure, and cooling that is provided in the adiabatic storage tank and cools the liquefied gas at the injection pressure to an overcooled state. A cooling tank for storing fluid; an injection nozzle for injecting the liquefied gas which is provided at the bottom of the heat insulation storage tank and cooled to a supercooled state; opening and closing means for opening and closing the injection nozzle; and A liquefied gas supply pipe for supplying a liquefied gas, a cooling fluid supply pipe for supplying the cooling fluid into the cooling tank, and a vaporized gas discharge pipe for discharging the cooling fluid gas vaporized in the cooling tank, The cooling tank is formed so that heat can be exchanged between the cooling fluid in the cooling tank and the liquefied gas in the heat insulating tank, and the opening / closing means is arranged in the liquefied gas.

  Further, in the liquefied gas injection device of the present invention, the liquefied gas at the injection pressure is liquid nitrogen having a pressure exceeding atmospheric pressure, the cooling fluid is liquid nitrogen saturated at atmospheric pressure or lower, and the seal gas is It is characterized by nitrogen gas. In addition, a seal gas injection unit that injects seal gas from the periphery of the injection nozzle, the cooling tank includes a heat transfer fin that comes into contact with the liquefied gas, and the opening and closing means includes a needle, The needle includes a stirrer that generates a turbulent flow in the flow of the liquefied gas in the cooling tank.

  According to the liquefied gas injection device of the present invention, since the liquefied gas to be injected can be kept in a supercooled state, flash vaporization at the time of injection can be suppressed, and the liquefied gas is injected into the object to be cooled as a liquid. can do. Further, by injecting the sealing gas so as to surround the nozzle, it is possible to prevent the atmosphere from being entrained in the nozzle portion, and to prevent moisture in the atmosphere from condensing and condensing in the nozzle portion. Furthermore, heat transfer efficiency can be improved by providing heat transfer fins or a stirring bar, and the liquefied gas to be injected can be effectively brought into a supercooled state.

It is a section front view showing an example of one form of a liquefied gas injection device of the present invention. It is a cross-sectional front view of the principal part which shows an example of a seal gas injection part. FIG. 3 is a sectional view taken along line III-III in FIG. 2. It is a cross-sectional top view which shows an example of a heat-transfer fin. It is a perspective view which shows an example of the needle which provided the stirring element.

  According to the liquefied gas injection device of the present invention, the liquefied gas to be injected is liquid nitrogen having a pressure of 0.5 MPa, the cooling fluid for cooling the liquefied gas to be injected is liquid nitrogen saturated at atmospheric pressure or lower, and the seal gas is nitrogen. An example of using gas will be described.

  The liquefied gas injection device shown in this embodiment is provided in a cylindrical heat insulating storage tank 11, a ring-shaped cooling tank 12 provided in the heat insulating storage tank 11, and a bottom plate 11 a that is a bottom portion of the heat insulating storage tank 11. An injection nozzle 13, a needle 14 serving as an opening / closing means for opening and closing the injection nozzle 13, a seal gas injection unit 15 provided on the lower surface of the bottom plate 11a of the heat insulation storage tank 11 so as to surround the injection nozzle 13, and the heat insulation storage tank 11 is a liquid nitrogen supply pipe 16 for supplying liquid nitrogen having a pressure of 0.5 MPa (hereinafter referred to as liquid nitrogen for injection), and liquid nitrogen that is saturated in the cooling tank 12 below atmospheric pressure. (Hereinafter referred to as “cooling liquid nitrogen”), a cooling liquid nitrogen supply pipe 17, a nitrogen gas discharge pipe 18 that discharges nitrogen gas evaporated from the cooling liquid nitrogen in the cooling tank 12 to the outside, and the sheet A seal gas supply pipe 19 for supplying seal gas (nitrogen gas) to the gas injection unit 15, and a needle driving device 20 for opening and closing the needle 14.

  The heat insulation storage tank 11 is a sealed container having a heat insulation layer around it, and the needle 14 penetrates airtightly in the center of the top plate 11b so as to be movable in the vertical direction. The heat insulating storage tank 11 is supplied with jetting liquid nitrogen having a predetermined jetting pressure (0.5 MPa in this embodiment) from the jetting liquid nitrogen supply pipe 16.

  The cooling tank 12 stores the cooling liquid nitrogen having a temperature at which the jetting liquid nitrogen in the heat insulating storage tank 11 can be cooled to a supercooled state, and the cooling liquid nitrogen via the tank wall of the cooling tank 12. The liquid nitrogen for injection is formed so as to be able to exchange heat, and the liquid nitrogen for injection is cooled to a supercooled state by indirectly exchanging the liquid nitrogen. At the center of the cooling tank 12, a vertical through-hole 12 a is provided that serves as an injection flow path through which liquid nitrogen for injection flows down toward the seal gas injection unit 15. Further, the needle 14 is disposed in the center of the through hole 12a so as to penetrate through the liquid nitrogen for injection. The cooling liquid nitrogen that is saturated at atmospheric pressure or lower is supplied into the cooling tank 12 from the cooling liquid nitrogen supply pipe 17. The position of the cooling tank 12 in the heat insulation storage tank 11 is set so that the lower end portion of the cooling tank 12 is positioned around the injection nozzle 13.

  The low-temperature nitrogen gas obtained by evaporating the cooling liquid nitrogen in the cooling bath 12 is discharged to the outside through the nitrogen gas discharge pipe 18. At this time, if the nitrogen gas discharge pipe 18 is open to the atmosphere, the inside of the cooling tank 12 becomes substantially atmospheric pressure, and the nitrogen gas in the nitrogen gas discharge pipe 18 is forcibly exhausted by a fan or the like. The inside of the cooling tank 12 becomes atmospheric pressure or less. Further, the cooling tank 12 is provided with a liquid level sensor 12S for detecting the liquid amount (liquid level) in the cooling tank 12, and based on the detection result of the liquid level sensor 12S, a cooling liquid nitrogen supply pipe is provided. The cooling liquefied gas supply valve 17V provided at 17 is opened and closed to keep the amount of cooling liquid nitrogen in the cooling bath 12 constant. When the consumption of cooling liquid nitrogen is constant, the cooling liquefied gas supply valve 17V can be a manual valve.

  As shown in FIG. 2, the injection nozzle 13 has an annular valve seat 13a corresponding to the conical valve portion 14a provided at the tip of the needle 14, and the needle 14 is raised so that the conical valve portion 14a is an annular valve. By separating from the seat 13a, the injection nozzle 13 is opened in a ring shape. The injection nozzle 13 is opened / closed by the needle 14 by the needle driving device 20 and can be opened / closed intermittently, and a predetermined opening degree can be maintained.

  The seal gas injection unit 15 is composed of a concave groove 15 a provided in an annular shape around the injection nozzle 13, and the seal gas (nitrogen gas) supplied from the seal gas supply pipe 19 is injected from the injection nozzle 13. The liquid is ejected from the groove 15a so as to wrap around the jetting liquid nitrogen.

  The injection liquid nitrogen supply pipe 16 is provided with an injection liquid nitrogen supply valve 16V. When the injection liquid nitrogen is injected from the injection nozzle 13, the injection liquid nitrogen supply valve 16V is held open. . From the downstream side of the injection liquid nitrogen supply valve 16V, the seal gas supply pipe 19 for supplying a part of the injection liquid nitrogen as a seal gas is branched. The seal gas supply pipe 19 is provided with a flow rate adjusting valve 19V and a vaporizer 19H, and a part of the jetting liquid nitrogen that has flowed into the seal gas supply pipe 19 is adjusted in flow rate by the flow rate adjusting valve 19V. Then, after vaporizing with the vaporizer 19H, it is supplied to the seal gas injection part 15, and it injects below to a hollow cylindrical state.

  In the liquefied gas injection device thus formed, the injection liquid nitrogen injected from the injection nozzle 13 is supplied from the injection liquid nitrogen supply pipe 16 into the heat insulating storage tank 11 at 0.5 MPa higher than the atmospheric pressure. Further, cooling liquid nitrogen that is saturated at atmospheric pressure or less is supplied from the cooling liquid nitrogen supply pipe 17 into the cooling tank 12. At this time, if the inside of the cooling tank 12 is at atmospheric pressure, the saturation temperature of the cooling liquid nitrogen in the cooling tank 12 is 77 K, so that 0.5 MPa of jetting liquid nitrogen in the heat insulating storage tank 11 (saturation temperature 97 K) Is cooled by indirect heat exchange with the cooling liquid nitrogen through the inner peripheral wall of the cooling tank 12 (the peripheral wall of the through hole 12a) while reaching the injection nozzle 13 through the through hole 12a, and then injected. Injected from the nozzle 13 toward the object to be cooled.

  When jetting liquid nitrogen in a saturated state at the same pressure by jetting the liquid nitrogen for jetting thus cooled from the jet nozzle 13 while maintaining the supercooled state cooled by the liquid nitrogen for cooling. In comparison, the amount of flash vaporization of the jetting liquid nitrogen jetted from the jet nozzle 13 can be greatly reduced. As a result, the amount of liquid nitrogen used for cooling can be reduced, and the spray range when sprayed from the same spray nozzle is wider than before, so cooling of the object to be cooled by liquid nitrogen is efficient. It can be carried out. Further, since the needle 14 is also sufficiently cooled by the jetting liquid nitrogen, the jetting liquid nitrogen jetted from the jet nozzle 13 is not heated.

  Furthermore, by injecting the seal gas into a cylindrical shape from the seal gas injection unit 15 provided around the injection nozzle 13, the atmosphere enters the injection nozzle 13 and the moisture in the atmosphere is condensed and condensed. Since it is possible to prevent the nozzle 13 from being blocked, liquid nitrogen can be stably ejected from the ejection nozzle 13 over a long period of time.

  Further, since the evaporating gas (nitrogen gas) released to the outside through the nitrogen gas discharge pipe 18 has a saturation temperature equal to or lower than the atmospheric pressure, the liquid nitrogen for injection in the portion in the heat insulating storage tank 11 of the nitrogen gas discharge pipe 18 is used. Can be cooled. In this case, the liquid nitrogen for injection can be more effectively cooled by forming a part of the nitrogen gas discharge pipe 18 in the heat insulating storage tank 11 in a coil shape or providing a fin.

  In this embodiment, nitrogen is used as all of the liquefied gas for injection, the cooling fluid, and the sealing gas, so that liquid nitrogen from one liquid nitrogen supply source can be appropriately distributed and used. Although the configuration can be simplified and the gas cost can be reduced, the liquefied gas for injection, the cooling fluid, and the seal gas can be different. Moreover, the structure of the heat insulation storage tank 11 and the cooling tank 12 can employ | adopt arbitrary structures according to the intended purpose of a liquefied gas injection apparatus, for example, the several cooling tank 12 and several injection | pouring to one heat insulation storage tank 11 It is also possible to provide a nozzle 13.

  Furthermore, as shown in FIG. 4, by providing the heat transfer fins 21 on the peripheral wall of the through hole 12a, the heat transfer area where heat is exchanged between the liquid nitrogen for injection and the liquid nitrogen for cooling is expanded to improve the heat exchange efficiency. The liquid nitrogen for injection can be cooled more effectively. In addition, the shape and the number of installation of the heat-transfer fin 21 are arbitrary, and a corrugated plate and a concavo-convex structure can be employed in addition to a flat plate.

  Further, as shown in FIG. 5, by providing a stirrer 22 around the needle 14, turbulent flow can be generated in the liquid nitrogen for injection flowing down in the through hole 12a, and the peripheral wall and transmission of the through hole 12a can be generated. Since the heat fin 21 and the jetting liquid nitrogen can be effectively brought into contact with each other, the heat exchange efficiency between the two liquid nitrogens can be further improved. In particular, in the case of intermittently injecting liquid nitrogen, since the injection liquid nitrogen can be agitated by the vertical movement of the needle 14 that opens and closes the injection nozzle 13, the entire injection liquid nitrogen is more reliably subcooled. State. In addition, the shape and the number of installation of the stirring bar 22 are arbitrary, and can be formed in a spiral shape or a blade shape.

  DESCRIPTION OF SYMBOLS 11 ... Thermal insulation storage tank, 11a ... Bottom plate, 11b ... Top plate, 12 ... Cooling tank, 12a ... Through-hole, 12S ... Liquid level sensor, 13 ... Injection nozzle, 13a ... Annular valve seat, 14 ... Needle, 14a ... Conical valve part 15 ... Seal gas injection section, 15a ... Groove, 16 ... Liquid nitrogen supply pipe for injection, 16V ... Liquid nitrogen supply valve for injection, 17 ... Liquid nitrogen supply pipe for cooling, 17V ... Liquid gas supply valve for cooling, 18 DESCRIPTION OF SYMBOLS ... Nitrogen gas discharge pipe, 19 ... Seal gas supply pipe, 19H ... Vaporizer, 19V ... Flow control valve, 20 ... Needle drive device, 21 ... Heat transfer fin, 22 ... Stirring

Claims (5)

  An adiabatic storage tank for storing liquefied gas at an injection pressure; a cooling tank for storing a cooling fluid provided in the adiabatic storage tank for cooling the liquefied gas at an injection pressure to a supercooled state; and provided at the bottom of the adiabatic storage tank. An injection nozzle for injecting the liquefied gas cooled to a supercooled state, opening / closing means for opening and closing the injection nozzle, a liquefied gas supply pipe for supplying the liquefied gas into the heat insulation storage tank, and an inside of the cooling tank. A cooling fluid supply pipe for supplying the cooling fluid; and a vaporized gas discharge pipe for discharging the cooling fluid gas vaporized in the cooling tank, wherein the cooling tank includes the cooling fluid in the cooling tank and the heat insulating tank. A liquefied gas injection apparatus, wherein the liquefied gas is formed so as to be capable of exchanging heat, and the opening / closing means is disposed in the liquefied gas.   The liquefied gas at the injection pressure is liquid nitrogen having a pressure exceeding atmospheric pressure, the cooling fluid is liquid nitrogen that is saturated at atmospheric pressure or lower, and the seal gas is nitrogen gas. The liquefied gas injection device according to 1.   The liquefied gas injection device according to claim 1, further comprising a seal gas injection unit that injects a seal gas from the periphery of the injection nozzle.   4. The liquefied gas injection device according to claim 1, wherein the cooling tank includes a heat transfer fin that comes into contact with the liquefied gas. 5.   The said opening / closing means consists of a needle, and this needle is equipped with the stirring bar which generates a turbulent flow in the flow of the said liquefied gas in a cooling tank, The any one of Claim 1 thru | or 4 characterized by the above-mentioned. Liquefied gas injection device.

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