JP7558780B2 - Sterile liquid nitrogen supply device - Google Patents

Description

The present invention relates to a sterile liquid nitrogen supply device.

A prior document disclosing the configuration of a sterilized cryogenic liquid supply device is U.S. Pat. No. 4,620,962 (Patent Document 1). The sterilized cryogenic liquid supply device described in Patent Document 1 comprises a liquid nitrogen storage tank, a heat exchanger, a sterilization means, a pressure vessel, and an insulated tank. Liquid nitrogen supplied from the liquid nitrogen storage tank is vaporized in the heat exchanger. The vaporized nitrogen gas is sterilized by passing through the sterilization means. The sterilized nitrogen gas is heat exchanged with liquid nitrogen supplied from the liquid nitrogen storage tank in the heat exchanger, and then supplied into the pressure vessel. The pressure vessel is immersed in liquid nitrogen supplied from the liquid nitrogen storage tank into the insulated tank. The nitrogen gas supplied into the pressure vessel is cooled and liquefied by the liquid nitrogen stored in the insulated tank and outside the pressure vessel.

U.S. Pat. No. 4,620,962

In the liquid supply device described in Patent Document 1, sterilized nitrogen gas is liquefied using liquid nitrogen other than the liquid nitrogen to be sterilized as a refrigerant, so the yield of sterilized liquid nitrogen obtained relative to the liquid nitrogen used is low.

The present invention has been made to solve the above problems, and aims to provide a sterile liquid nitrogen supply device that can improve the yield of sterile liquid nitrogen obtained per unit of liquid nitrogen used.

The sterile liquid nitrogen supply device according to the present invention comprises a liquid nitrogen supply source, a tank, a pump, a sterilizing filter, a first heat exchanger, and a second heat exchanger. The liquid nitrogen supply source supplies liquid nitrogen. The tank stores liquid nitrogen supplied from the liquid nitrogen supply source and nitrogen gas vaporized from the liquid nitrogen. The pump pressurizes the nitrogen gas in the tank. The nitrogen gas pressurized by the pump flows through the sterilizing filter. The first heat exchanger exchanges heat between the nitrogen gas that has passed through the sterilizing filter and the nitrogen gas before passing through the pump. The second heat exchanger is immersed in liquid nitrogen in the tank, and liquefies the nitrogen gas that has passed through the first heat exchanger by heat exchange with the liquid nitrogen in the tank.

In one embodiment of the present invention, the pressure of the nitrogen gas flowing between the tank and the pump is lower than atmospheric pressure.

In one embodiment of the present invention, the sterile liquid nitrogen supply device further includes a nitrogen gas supply unit that supplies a portion of the nitrogen gas flowing between the sterilizing filter and the first heat exchanger to the outside.

In one embodiment of the present invention, the sterile liquid nitrogen supply device further includes a nitrogen gas supply unit that supplies a portion of the nitrogen gas flowing between the pump and the sterilizing filter to the outside.

In one embodiment of the present invention, the sterile liquid nitrogen supply device further includes a third heat exchanger. The third heat exchanger cools the liquid nitrogen supplied from the liquid nitrogen supply source by exchanging heat with the nitrogen gas flowing between the tank and the pump.

The sterile liquid nitrogen supply device in one embodiment of the present invention further includes a fourth heat exchanger. The fourth heat exchanger cools the nitrogen gas flowing between the pump and the sterilization filter by exchanging heat with cooling water between the pump and the sterilization filter.

The present invention can improve the yield of sterile liquid nitrogen obtained relative to the amount of liquid nitrogen used.

1 is a system diagram showing a configuration of a sterile liquid nitrogen supply device according to one embodiment of the present invention. FIG. 2 is a system diagram showing the configuration of a sterile liquid nitrogen supply device according to a comparative example. FIG. 11 is a system diagram showing the configuration of a sterile liquid nitrogen supply device according to a modified example of an embodiment of the present invention.

The following describes an apparatus according to one embodiment of the present invention with reference to the drawings. In the following description of the embodiment, the same or corresponding parts in the drawings are given the same reference numerals, and their description will not be repeated.

The temperature, pressure, or flow rate of the liquid nitrogen and nitrogen gas in the sterile liquid nitrogen supply device of one embodiment of the present invention is an analytical value obtained by simulation. °C (degrees Celsius) is used as a unit of temperature. PaG (gauge pressure) is used as a unit of pressure. ^Nm3 /h (normal cubic meters per unit time) is used as a unit of flow rate. Furthermore, the term "sterility" in the sterile liquid nitrogen of one embodiment of the present invention refers to a quantity of bacteria that is not more than the quantity that will have no effect on the beverage or the body of the person drinking the beverage in so-called aseptic filling, in which a beverage is filled into a beverage container in a sterilized nitrogen atmosphere.

Figure 1 is a system diagram showing the configuration of a sterile liquid nitrogen supplying apparatus according to one embodiment of the present invention. As shown in Figure 1, the sterile liquid nitrogen supplying apparatus 1 includes a liquid nitrogen supply source 100, a tank 120, a pump 140, a sterilizing filter 160, a first heat exchanger 130, and a second heat exchanger 180. The sterile liquid nitrogen supplying apparatus 1 according to one embodiment of the present invention further includes a third heat exchanger 110, a fourth heat exchanger 150, a fifth heat exchanger 135, a heater 145, a nitrogen gas supply unit 170, a storage tank 190, and a dripper 192.

The liquid nitrogen supply source 100 supplies 10 L of liquid nitrogen. The liquid nitrogen supply source 100 is, for example, a cold evaporator. The inside of the liquid nitrogen supply source 100 is kept at positive pressure.

The liquid nitrogen supply source 100 is connected to the tank 120 by the first flow path section 11. 10L of liquid nitrogen supplied from the liquid nitrogen supply source 100 flows through the first flow path section 11. The first flow path section 11 passes through the third heat exchanger 110. A valve 101 is provided at a position between the liquid nitrogen supply source 100 and the third heat exchanger 110 in the first flow path section 11. A valve 111 is provided at a position between the third heat exchanger 110 and the tank 120 in the first flow path section 11.

The tank 120 stores 10L of liquid nitrogen supplied from the liquid nitrogen supply source 100 and 10G of nitrogen gas vaporized from the 10L of liquid nitrogen. In this embodiment, a level sensor is provided inside the tank 120 to detect the liquid level of the 10L of liquid nitrogen. The level sensor is, for example, a differential pressure sensor. The tank 120 is connected to the pump 140 by a second flow path 12 through which the nitrogen gas 10G flows. The second flow path 12 passes through the third heat exchanger 110, the first heat exchanger 130, and the fifth heat exchanger 135 in this order. In the tank 120, the second heat exchanger 180 is immersed in the 10L of liquid nitrogen.

Valve 101 is, for example, a pressure regulating valve. Valve 101 adjusts the pressure and flow rate of 10 L of liquid nitrogen supplied from liquid nitrogen supply source 100. Valve 111 opens and closes depending on the liquid level of 10 L of liquid nitrogen in tank 120 detected by a level sensor. Valve 111 adjusts the liquid level in tank 120 to be within a certain range, thereby maintaining second heat exchanger 180 immersed in 10 L of liquid nitrogen.

The third heat exchanger 110 cools the liquid nitrogen 10L supplied from the liquid nitrogen supply source 100 by heat exchange with the nitrogen gas 10G flowing between the tank 120 and the pump 140. Specifically, in the third heat exchanger 110, the liquid nitrogen 10L flowing through the first flow path section 11 is cooled by heat exchange with the nitrogen gas 10G flowing through the second flow path section 12.

The liquid nitrogen 10 L flowing between the liquid nitrogen supply source 100 and the third heat exchanger 110 in the first flow path section 11 has, for example, a temperature of -179.1°C, a pressure of 400 kPaG, and a flow rate of 38 Nm ³ /h.

By being cooled in the third heat exchanger 110, the 10 L of liquid nitrogen flowing between the third heat exchanger 110 and the tank 120 in the first flow path section 11 has, for example, a temperature of -182.0°C and a pressure of 395 kPaG.

The liquid nitrogen 10L that has been cooled by passing through the third heat exchanger 110 flows into the tank 120. By providing the third heat exchanger 110, the temperature of the liquid nitrogen 10L stored in the tank 120 can be lowered compared to when the third heat exchanger 110 is not provided.

The pump 140 pumps the nitrogen gas 10G in the tank 120. As a result of the pump 140 pumping, the pressure of the nitrogen gas 10G flowing between the tank 120 and the pump 140 is lower than atmospheric pressure. The nitrogen gas 10G flowing between the tank 120 and the third heat exchanger 110 has, for example, a temperature of -201.3°C and a pressure of -51 kPaG.

The pressure of the nitrogen gas 10G and liquid nitrogen 10L in the tank 120 becomes lower than atmospheric pressure, so that the temperature becomes lower than -195.8°C, which is the boiling point of nitrogen at atmospheric pressure. This makes it possible to lower the temperature of the sterile liquid nitrogen 10LS (described below) that is heat exchanged with the liquid nitrogen 10L in the tank 120 by the second heat exchanger 180 to a temperature lower than -195.8°C.

By being heated in the third heat exchanger 110, the nitrogen gas 10G flowing between the third heat exchanger 110 and the first heat exchanger 130 in the second flow path section 12 has, for example, a temperature of -181.1°C and a pressure of -56 kPaG. The pressure of the nitrogen gas 10G in the second flow path section 12 decreases the closer it is to the pump 140.

The first heat exchanger 130 exchanges heat between the nitrogen gas 10GS that has passed through the sterilization filter 160 (described later) and the nitrogen gas 10G before passing through the pump 140. Specifically, the nitrogen gas 10G flowing through the second flow path section 12 is heated in the first heat exchanger 130 by heat exchange with the nitrogen gas 10G flowing through the third flow path section 13 (described later). The nitrogen gas 10G flowing between the first heat exchanger 130 and the fifth heat exchanger 135 in the second flow path section 12 has, for example, a temperature of -46.5°C and a pressure of -61 kPaG.

The fifth heat exchanger 135 heats the nitrogen gas 10G that has passed through the first heat exchanger 130 in the second flow path section 12 by exchanging heat with the outside air. In the fifth heat exchanger 135, fins are provided on the outer periphery of the second flow path section 12 to ensure a contact area with the outside air. The nitrogen gas 10G that flows between the fifth heat exchanger 135 and the pump 140 in the second flow path section 12 has, for example, a temperature of 32.0°C and a pressure of -61 kPaG.

Pump 140 is, for example, a vacuum pump. Pump 140 is not limited to a vacuum pump, and may be a compressor as long as it can reduce the pressure inside tank 120 to below atmospheric pressure and pump out nitrogen gas 10G inside tank 120. Pump 140 is inverter-controlled according to the suction pressure, and the suction pressure is kept constant.

The pump 140 is connected to the storage tank 190 by the third flow path section 13. The third flow path section 13 passes through the fourth heat exchanger 150, the first heat exchanger 130, and the second heat exchanger 180 in this order.

The nitrogen gas 10G flowing between the pump 140 and the heater 145 in the third flow path portion 13 has, for example, a temperature of 252.6° C., a pressure of 223 kPaG, and a flow rate of 38 Nm ³ /h.

A heater 145 is provided at a position between the pump 140 and the fourth heat exchanger 150 in the third flow path section 13. The heater 145 is, for example, a sheath heater having a nichrome wire inside. The heater 145 heats the nitrogen gas 10G by placing a sheath in the third flow path section 13 and bringing the nitrogen gas 10G into contact with the sheath. Note that the heater 145 is not limited to a sheath heater, and may be arranged outside the third flow path section 13 and heat the nitrogen gas 10G through the third flow path section 13.

The nitrogen gas 10G flowing through the third flow path section 13 is sterilized by being heated by the heater 145. This heat sterilization can kill pathogenic and harmful bacteria and other microorganisms in the nitrogen gas 10G. The heating temperature of the heater 145 is, for example, 100°C or higher and 300°C or lower. Note that the heater 145 does not need to be provided if the nitrogen gas 10G is sufficiently sterilized by the increase in temperature of the nitrogen gas 10G when pressurized by the pump 140.

The fourth heat exchanger 150 cools the nitrogen gas 10G that has passed through the heater 145 in the third flow path section 13 by exchanging heat with the cooling water. Specifically, as shown in FIG. 1, the fourth heat exchanger 150 cools the nitrogen gas 10G flowing through the third flow path section 13 by exchanging heat with the cooling water that is supplied from the cooling water supply source 20 and flows through the cooling water flow path 21. The cooling water is drained to the outside from the drain section 22.

A sterilization filter 160 is provided at a position between the fourth heat exchanger 150 and the first heat exchanger 130 in the third flow path section 13. Nitrogen gas 10G pumped by the pump 140 flows through the sterilization filter 160. Specifically, the nitrogen gas 10G flowing through the fourth heat exchanger 150 passes through the sterilization filter 160. When passing through the sterilization filter 160, microorganisms such as bacteria in the nitrogen gas 10G are removed.

The sterilization filter 160 is, for example, a metal filter such as stainless steel or aluminum, or a resin filter such as polyethylene or polypropylene.

The mesh size of the sterilization filter 160 is, for example, 0.01 μm or more and 0.2 μm or less. The mesh size of the sterilization filter 160 and the size of the sterilization filter 160 itself are set to a size that can capture microorganisms such as bacteria contained in the nitrogen gas 10G while ensuring the required flow rate of the nitrogen gas 10GS.

When the sterilization filter 160 is used in combination with other sterilization means such as a heater 145, it is preferable that the sterilization filter 160 is provided at the most downstream position of the third flow path section 13 among these sterilization means. Other sterilization means may include a means for sterilizing the nitrogen gas 10G by ultraviolet irradiation.

A fifth flow path section 15, through which nitrogen gas 10GS flows, is connected to a position between the sterilization filter 160 and the first heat exchanger 130 in the third flow path section 13. The nitrogen gas 10GS that flows through the fifth flow path section 15 is discharged from the nitrogen gas supply section 170. That is, the nitrogen gas supply section 170 supplies a portion of the nitrogen gas 10GS flowing between the sterilization filter 160 and the first heat exchanger 130 to the outside. The sterilized nitrogen gas 10GS supplied from the nitrogen gas supply section 170 is used, for example, as a purge gas when aseptically filling.

The nitrogen gas 10GS flowing through the fifth flow path section 15 has, for example, a temperature of 34° C., a pressure of 206 kPaG, and a flow rate of 15 Nm ³ /h. In this embodiment, the flow rate of the nitrogen gas 10GS supplied from the nitrogen gas supply section 170 is about 39% of the flow rate of the liquid nitrogen 10L supplied from the liquid nitrogen supply source 100, but this ratio is not limited to about 39% and is set according to the amount of liquid nitrogen 10L in the tank 120 required to liquefy the sterilized nitrogen gas 10GS into sterile liquid nitrogen 10LS in the second heat exchanger 180, as described below.

The nitrogen gas 10GS flowing between the first heat exchanger 130 and the connection position of the third flow path section 13 with the fifth flow path section 15 has, for example, a temperature of 34° C., a pressure of 205 kPaG, and a flow rate of 23 Nm ³ /h.

In the first heat exchanger 130, the nitrogen gas 10GS flowing through the third flow path section 13 is cooled by heat exchange with the nitrogen gas 10G flowing through the second flow path section 12. The nitrogen gas 10GS flowing between the first heat exchanger 130 and the second heat exchanger 180 in the third flow path section 13 has, for example, a temperature of -169.3°C and a pressure of 200 kPaG.

The third flow path section 13 passes through the tank 120 and through a second heat exchanger 180 provided inside the tank 120. The second heat exchanger 180 liquefies the nitrogen gas 10GS that has passed through the first heat exchanger 130 by heat exchange with 10L of liquid nitrogen in the tank 120.

In the second heat exchanger 180, the nitrogen gas 10GS flowing through the third flow path section 13 exchanges heat with the liquid nitrogen 10L present in the tank 120 and outside the second heat exchanger 180, and is cooled and liquefied to become sterile liquid nitrogen 10LS. The second heat exchanger 180 is, for example, a fin-tube type heat exchanger.

In the third flow path section 13, the sterile liquid nitrogen 10LS flowing between the second heat exchanger 180 and the storage tank 190 has, for example, a temperature of -197.1°C, a pressure of 200 kPaG, and a flow rate of ²³ Nm3/h. The temperature of the sterile liquid nitrogen 10LS is lower than -195.8°C, which is the boiling point of nitrogen at atmospheric pressure.

The storage tank 190 stores the sterile liquid nitrogen 10LS that has flowed through the third flow path section 13. The inside of the storage tank 190 is maintained at a pressure higher than atmospheric pressure. The storage tank 190 is connected to the fourth flow path section 14, through which the sterile liquid nitrogen 10LS flows. The sterile liquid nitrogen 10LS that has flowed through the fourth flow path section 14 is supplied from a dripper 192. The fourth flow path section 14 is provided with a valve 191.

The 10LS of sterile liquid nitrogen supplied from the dripper 192 is dripped, for example, into the upper space inside the beverage container after the beverage has been filled. By filling the beverage container with inert nitrogen, oxidation of the beverage can be prevented, and the strength of the beverage container can be increased by utilizing the increase in internal pressure inside the beverage container caused by the evaporation of the 10LS of sterile liquid nitrogen.

In the sterile liquid nitrogen supply system 1, 10 L of liquid nitrogen to be sterilized is used as a refrigerant to cool and liquefy 10 GS of sterilized nitrogen gas. As a result, the yield of 10 LS of sterile liquid nitrogen obtained per 10 L of liquid nitrogen used in the sterile liquid nitrogen supply system 1 is approximately 61%.

Here, we will explain the results of a simulation analysis of the yield of sterile liquid nitrogen 10 obtained per liquid nitrogen used in a comparative example of a sterile liquid nitrogen supply device in which sterilized nitrogen gas is liquefied using liquid nitrogen other than the liquid nitrogen to be sterilized as a refrigerant.

Figure 2 is a system diagram showing the configuration of a sterile liquid nitrogen supplying device according to a comparative example. As shown in Figure 2, the sterile liquid nitrogen supplying device 9 according to the comparative example includes a liquid nitrogen storage tank 900, a heat exchanger 910, a sterilization means 920, a pressure vessel 930, and an insulated tank 940.

For example, 90 L of liquid nitrogen having a temperature of -179.1°C and a pressure of 400 kPaG is supplied from the liquid nitrogen storage tank 900. A portion of the liquid nitrogen 90 L supplied from the liquid nitrogen storage tank 900 flows through the first flow path section 91 and exchanges heat with sterilized nitrogen gas 90GS (described below) in the heat exchanger 910, where it is heated and vaporized.

The nitrogen gas 90G vaporized in the heat exchanger 910 flows through the second flow path section 92 and is sterilized in the sterilization means 920. The temperature of the nitrogen gas 90G flowing through the second flow path section 92 is, for example, -150.0°C. The nitrogen gas 90GS sterilized in the sterilization means 920 flows through the third flow path section 93 and exchanges heat with a portion of the liquid nitrogen 90L in the heat exchanger 910.

The sterilized nitrogen gas 90GS cooled in the heat exchanger 910 flows through the fourth flow path section 94 and is sent into the pressure vessel 930. The temperature of the sterilized nitrogen gas 90GS flowing through the fourth flow path section 94 is, for example, -177.1°C.

The pressure vessel 930 is disposed inside the insulated tank 940. A portion of the 90 L of liquid nitrogen supplied from the liquid nitrogen storage tank 900 through the fifth flow path section 95 is stored in the insulated tank 940. The liquid level of the 90 L of liquid nitrogen in the insulated tank 940 is adjusted to be within a certain range by a float valve 950 having a float 960. The pressure vessel 930 is immersed in the 90 L of liquid nitrogen in the insulated tank 940.

The sterilized nitrogen gas 90GS sent into the pressure vessel 930 is cooled and liquefied by the liquid nitrogen 90L inside the insulated tank 940 and outside the pressure vessel 930, and becomes sterile liquid nitrogen 90LS. The sterile liquid nitrogen 90LS is discharged from the pressure vessel 930 through the sixth flow path portion 96. The sterile liquid nitrogen 90LS flowing through the sixth flow path portion 96 has, for example, a temperature of -193.8°C, a pressure of 200 kPaG, and a flow rate of 23.0 ^Nm3 /h.

A portion of the liquid nitrogen 90L inside the thermal insulation tank 940 and outside the pressure vessel 930 is vaporized and released to the outside through the seventh flow path portion 97. The nitrogen gas 90G flowing through the seventh flow path portion 97 has, for example, a temperature of −195.8° C., a pressure of 0 kPaG, and a flow rate of 29.7 Nm ³ /h.

In the sterile liquid nitrogen supplying device 9, the sterilized nitrogen gas is liquefied using liquid nitrogen other than the liquid nitrogen to be sterilized as a refrigerant, and the nitrogen gas 90G vaporized from the liquid nitrogen used as the refrigerant is discharged to the outside. As a result, the yield of 90LS of sterile liquid nitrogen obtained from 90L of liquid nitrogen used in the sterile liquid nitrogen supplying device 9 of the comparative example was about 44%, which was lower than the yield of about 61% of the sterile liquid nitrogen supplying device 1 of the present embodiment. From the above simulation results, it was confirmed that the yield of 10LS of sterile liquid nitrogen obtained from 10L of liquid nitrogen used in the sterile liquid nitrogen supplying device 1 of the present embodiment is improved by using 10L of liquid nitrogen to be sterilized as a refrigerant for cooling and liquefying the sterilized nitrogen gas 10GS.

In the sterile liquid nitrogen supply device 1 according to one embodiment of the present invention, the inside of the tank 120 is depressurized to a pressure lower than atmospheric pressure by the pump 140, so that the sterilized nitrogen gas 10GS that is heat exchanged with the liquid nitrogen 10L in the tank 120 in the second heat exchanger 180 can be efficiently cooled, thereby improving the yield of sterile liquid nitrogen 10LS obtained per 10L of liquid nitrogen used.

In one embodiment of the present invention, the sterile liquid nitrogen supply device 1 further includes a nitrogen gas supply unit 170 that supplies a portion of the nitrogen gas 10GS flowing between the sterilizing filter 160 and the first heat exchanger 130 to the outside, thereby making it possible to effectively utilize the sterilized nitrogen gas 10GS and improving the efficiency of use of the liquid nitrogen 10L supplied from the liquid nitrogen supply source 100.

In the sterile liquid nitrogen supply device 1 according to one embodiment of the present invention, the liquid nitrogen 10L flowing into the tank 120 can be cooled by heat exchange in the third heat exchanger 110 between the liquid nitrogen 10L flowing through the first flow path section 11 and the nitrogen gas 10G flowing through the second flow path section 12. As a result, the sterilized nitrogen gas 10GS that is heat exchanged with the liquid nitrogen 10L in the tank 120 in the second heat exchanger 180 can be efficiently cooled, thereby improving the yield of sterile liquid nitrogen 10LS obtained per 10L of liquid nitrogen used.

In the sterile liquid nitrogen supply device 1 according to one embodiment of the present invention, the nitrogen gas 10G flowing through the third flow path section 13 can be cooled by heat exchange with cooling water in the fourth heat exchanger 150, so the temperature of the nitrogen gas 10G passing through the sterilization filter 160 can be lowered. This eliminates the need for the sterilization filter 160 to be heat resistant, allowing for greater freedom in the material that constitutes the sterilization filter 160.

The following describes a sterile liquid nitrogen supplying device according to a modified embodiment of the present invention. The sterile liquid nitrogen supplying device according to the modified embodiment of the present invention has a different connection position between the third flow path section and the fifth flow path section from the sterile liquid nitrogen supplying device 1 according to the embodiment of the present invention, so the description of the configuration that is similar to that of the sterile liquid nitrogen supplying device 1 according to the embodiment of the present invention will not be repeated.

Figure 3 is a system diagram showing the configuration of a sterile liquid nitrogen supplying device according to a modified embodiment of the present invention. As shown in Figure 3, in the sterile liquid nitrogen supplying device 1A according to the modified embodiment of the present invention, a fifth flow path section 15A through which nitrogen gas 10G flows is connected to a position between the pump 140 and the sterilization filter 160 in the third flow path section 13. The nitrogen gas 10G that flows through the fifth flow path section 15A is discharged from the nitrogen gas supply section 170. That is, the nitrogen gas supply section 170 supplies a portion of the nitrogen gas 10G flowing between the pump 140 and the sterilization filter 160 to the outside. The nitrogen gas 10G supplied from the nitrogen gas supply section 170 is used, for example, as an inert gas that does not need to be sterilized.

In a modified embodiment of the present invention, the sterile liquid nitrogen supplying device 1A further includes a nitrogen gas supplying section 170 that supplies a portion of the nitrogen gas 10G flowing between the pump 140 and the sterilizing filter 160 to the outside, thereby making effective use of the nitrogen gas 10G and extending the life of the sterilizing filter 160.

The above-mentioned sterile liquid nitrogen supply device is exemplified using liquid nitrogen, but it is not limited to liquid nitrogen and can also be applied to other inert cryogenic liquids such as liquid helium or liquid argon.

The above disclosed embodiments are illustrative in all respects and are not intended to be a basis for restrictive interpretation. Therefore, the technical scope of this disclosure should not be interpreted solely by the above-described embodiments. Furthermore, all modifications within the meaning and scope equivalent to the claims are included. In the above description of the embodiments, configurations that can be combined may be combined with each other.

1, 1A, 9 Sterile liquid nitrogen supply device, 10G, 10GS, 90G, 90GS Nitrogen gas, 10L, 90L Liquid nitrogen, 10LS, 90LS Sterile liquid nitrogen, 11, 91 First flow path section, 12, 92 Second flow path section, 13, 93 Third flow path section, 14, 94 Fourth flow path section, 15, 15A, 95 Fifth flow path section, 96 Sixth flow path section, 97 Seventh flow path section, 20 Cooling water supply source, 21 Cooling water flow path, 22 Drainage section, 100 Liquid nitrogen supply source, 101, 111, 191, 950 Valve, 110 Third heat exchanger, 120 Tank, 130 First heat exchanger, 135 Fifth heat exchanger, 140 Pump, 145 Heater, 150 Fourth heat exchanger, 160 Sterilization filter, 170 Nitrogen gas supply unit, 180 second heat exchanger, 190 storage tank, 192 dripper, 900 liquid nitrogen storage tank, 910 heat exchanger, 920 sterilization means, 930 pressure vessel, 940 insulated tank, 960 float.

Claims (6)

a liquid nitrogen supply source for supplying liquid nitrogen;
a tank for storing the liquid nitrogen supplied from the liquid nitrogen supply source and nitrogen gas vaporized from the liquid nitrogen;
A pump that pumps the nitrogen gas in the tank;
a sterilization filter through which the nitrogen gas pumped by the pump flows;
a first heat exchanger that exchanges heat between the nitrogen gas that has passed through the sterilization filter and the nitrogen gas that has been pumped out of the tank by the pump;
A sterile liquid nitrogen supply device comprising: a second heat exchanger that is immersed in the liquid nitrogen in the tank and liquefies the nitrogen gas that has passed through the first heat exchanger by heat exchange with the liquid nitrogen in the tank. The sterile liquid nitrogen supply device according to claim 1, wherein the pressure of the nitrogen gas flowing between the tank and the pump is lower than atmospheric pressure. The sterile liquid nitrogen supply device according to claim 1 or 2, further comprising a nitrogen gas supply unit that supplies a portion of the nitrogen gas flowing between the sterilizing filter and the first heat exchanger to the outside. The sterile liquid nitrogen supply device according to claim 1 or 2, further comprising a nitrogen gas supply unit that supplies a portion of the nitrogen gas flowing between the pump and the sterilizing filter to the outside. The sterile liquid nitrogen supply device according to any one of claims 1 to 4, further comprising a third heat exchanger that cools the liquid nitrogen supplied from the liquid nitrogen supply source by heat exchange with the nitrogen gas flowing between the tank and the pump. The sterile liquid nitrogen supply device according to any one of claims 1 to 5, further comprising a fourth heat exchanger between the pump and the sterilizing filter, which exchanges heat with cooling water to cool the nitrogen gas flowing between the pump and the sterilizing filter.

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