JPH07260094A - Extremely low temperature container - Google Patents

Abstract

PURPOSE:To readily perform the cleaning work of a pipeline without knocking down pipings by inserting heaters in a part positioned inside the vacuum container of the pipings which are outwardly led from a helium container, and providing valves to be opened during a heater heating period in a part positioned outside the vacuum container. CONSTITUTION:A heater 11 or 13 is inserted in a low pressure side outlet piping 4a or a high pressure side outlet piping 5a which is outwardly led from the vacuum container 3 of a helium container. A part positioned inside the vacuum container 3 of the low pressure side outlet piping 4a or the high pressure side outlet piping 5a is heated by inputting the switch 16 of an electric power supply 15 so as to evaporate solid air which is frozen and set, and open a low pressure side discharge valve 17 or a high pressure side discharge valve 18 for a predetermined time only. Hereby, the cleaning work inside the pipings is readily performed without knocking down the pipings themselves.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cryogenic container comprising a helium container containing liquid helium and the like and a vacuum container containing the helium container.

[0002]

2. Description of the Related Art A conventional cryogenic container is shown in FIG. 7, and FIG. 8 is a partially enlarged view of a pipe taking-out portion of a cryogenic container equipped with the liquid level gauge shown in FIG. In the figure, 1 is a helium container in which a liquid helium 2 is housed, 3 is a vacuum container in which a helium container 2 is housed, and the inside is maintained in a vacuum. A low-pressure side piping system 5 composed of a low-pressure side withdrawing pipe 4a led out to the outside and a connecting pipe 4b connected in a T-branching manner at the outer end of the vacuum container 3 of this pipe is designated by 5 from the bottom of the helium container 1. A high-pressure side piping system composed of a high-pressure side withdrawing pipe 5a that penetrates the wall of the vacuum container 3 and is led to the outside, and a connection pipe 5b that is T-branched and connected at the external end of the vacuum container 3 of this pipe. is there. The internal pressure of the helium container 1 is adjusted to release a gas at a pressure slightly higher than the atmospheric pressure by attaching a pressure adjusting valve to an injection port (not shown) or the like, and the internal pressure is maintained at a constant value. Reference numeral 7 is a differential pressure type liquid level gauge which is connected to the low pressure side piping system 4 and the high pressure side piping system 5 and detects the liquid level of liquid helium in the helium container 1 based on the difference in internal pressure between the respective piping systems. 8 is the low pressure side piping system 4
A pressure gauge connected to the helium container 1 to display the internal pressure of the helium container 1. Reference numeral 9 is a pressure equalizing cock for confirming the operation of the differential pressure type liquid surface juice 8.

The high-pressure side piping system 5 is connected to the bottom of the helium container 1 and is led out to the outside. The portion of the high-pressure piping system 5 located inside the vacuum container 3 has a temperature inside the vacuum container 3 which is liquid. Since it is higher than the liquefaction temperature of helium (4.2K), helium is in a gas state, and the internal pressure of the high-pressure side piping system 5 is the difference between the bottom of the helium container 1 and the liquid surface position of the liquid helium 2. The specific gravity of liquid helium (0.
1248 g / cm ³ ) multiplied by the internal pressure of the low pressure side piping system 4, and the differential pressure type flow level gauge has the above internal pressure of the high pressure side piping system 5 and the low pressure side piping system 5 The liquid level position of the liquid helium in the helium container 1 can be detected by the difference with the internal pressure.

Reference numeral 11 is a heater inserted in the inner diameter portion of the low pressure side lead-out pipe 4a, and is sealed by a bush 12 at the external pipe end. A heater 13 is inserted into the inner portion of the high-pressure side pipe 5a, and is sealed by a bush 14 at the outer pipe end. The connection pipes 4b and 5b are T-branched and connected at the outer ends of the low-pressure side extraction pipe 4a and the high-pressure side extraction pipe 5a, respectively.
Each of the heaters 11 and 13 is connected to a power supply 15 via a power switch 16.

In the conventional cryogenic container thus constructed, the internal pressure of the helium container 1 is set to a pressure slightly higher than the atmospheric pressure in a normal state, but it suddenly increases during long-term use. The pressure of the helium container 1 becomes a negative pressure due to the atmospheric pressure fluctuation and the rapid change of the ambient temperature, or
Ambient air may infiltrate gradually due to diffusion phenomenon in the piping system joints, etc. The invaded air is cooled by the liquid helium 2 and freezes to become a solid, and the low pressure side piping system 4 and the high pressure side piping system There is a case where the pipe system is blocked by being adhered to the inner diameter portion of No. 5 mainly located in the vacuum container 3. If the piping system is blocked, the differential pressure type liquid level gauge 7 will not operate, so disassemble a part of the piping about once a year, and use the heaters 11 and 1
A cleaning operation is performed about once a year, in which an electric current is applied to 3 to discharge the frozen solid air.

[0006]

Since the conventional cryogenic container is constructed as described above, a troublesome work of disassembling a part of the pipe each time the cleaning work of the pipe is carried out and reassembling after the cleaning work. Was needed.

The present invention has been made to solve the above-mentioned problems, and the cleaning work of the piping system connecting the helium container and the differential pressure type level gauge can be easily performed without disassembling the piping. The purpose is to do so.

[0008]

In a cryogenic container according to claim 1 of the present invention, a heater is inserted into a portion of the pipe led out of the helium container to the outside, which is located in the vacuum container, and is placed outside the vacuum container. A valve that discharges when the heater is heated is provided at the position where it is located.

A cryogenic container according to claim 2 of the present invention is
Each vacuum container of the low pressure side piping system that is connected from the top of the helium container to the differential pressure level gauge through the wall of the vacuum container and the high pressure side piping system that is connected to the outside of the vacuum container from the bottom of the helium container. A heater is inserted into each of the inside portions, and a discharge valve that discharges when the heater is heated is provided in the portion outside the vacuum container.

The cryogenic container according to claim 3 of the present invention includes a low pressure side piping system and a high pressure side piping system which are connected to the differential pressure level gauge from the helium container. This system is provided with a three-way valve that is released when the heater is heated.

Further, the cryogenic container according to claim 4 of the present invention is provided in a portion of the low pressure side and high pressure side piping system connected to the differential pressure level gauge from the helium container, outside the vacuum container. A switch for detecting the opening / closing operation of the discharge valve is provided so that the power supply for supplying power to the heater is opened / closed in conjunction with the opening / closing operation.

The cryogenic container according to claim 5 of the present invention detects the switching operation of the three-way valves provided in the low pressure side and high pressure side piping systems connected from the helium container to the differential pressure type level gauge. A switch is provided so that the power supply for supplying power to the heater is opened and closed in conjunction with the switching operation.

In the cryogenic container according to claim 6 of the present invention, the discharge valve provided in the low pressure side and high pressure side piping systems connected from the helium container to the differential pressure type level gauge is an electromagnetic valve, and the heater The solenoid valve is opened and closed simultaneously with the opening and closing of the power supply.

In the cryogenic container according to claim 7 of the present invention, the discharge valve provided in the low pressure side and high pressure side piping systems connected from the helium container to the differential pressure type level gauge is an electromagnetic valve, and the heater is A timer is provided in which the solenoid valve opens after a lapse of a predetermined time after the power is turned on, and the solenoid valve is closed at the same time when the power supply is opened.

[0015]

The cryogenic container according to claim 1 of the present invention is provided with a valve capable of discharging when the heater is heated, in a portion of the pipe led out of the helium container to the outside of the vacuum container and located outside the vacuum container. The cleaning operation for removing the solid air that has invaded into the inside and frozen and adhered can be easily performed by switching the heater power supply and opening / closing the releasable valve without disassembling the pipe.

In the cryogenic container according to claim 2 of the present invention, each of the low pressure side piping system and the high pressure side piping system, which are connected to the differential pressure level gauge from the helium container, is located outside the vacuum container. Since the discharge valve that discharges when the heater is heated is installed in the heater, cleaning work to remove solid air that has entered the piping system and frozen and stuck can be performed by switching the heater power supply and opening and closing the discharge valve without disassembling the piping system. It can be carried out.

Further, the cryogenic container according to claim 3 of the present invention includes a low pressure side piping system and a high pressure side piping system which are connected to the differential pressure type liquid level gauge from the helium container, respectively, and are located outside the vacuum container. Since a three-way valve that is released when the heater is heated is installed on the heater, the cleaning work to remove the solid air that has entered the piping system and frozen and stuck is not required to disassemble the piping system, but to switch the heater power supply and switch the three-way valve. Thus, the discharge operation can be limited to the cryogenic container side of the low pressure side and high pressure side piping systems.

The cryogenic container according to claim 4 of the present invention is an opening / closing operation of a discharge valve provided in a portion located outside a vacuum container of a piping system connected from a helium container to a differential pressure type level gauge. The heater power supply is opened / closed by interlocking with the opening / closing operation of the discharge valve by detecting the switch, so cleaning work to remove solid air that has entered the piping system and frozen and stuck can be done simply by operating the valve. It can be carried out.

The cryogenic container according to claim 5 of the present invention is a three-way valve switching operation provided at a portion of the piping system connected to the differential pressure level gauge outside the vacuum container of the helium container. The heater power supply is opened and closed by interlocking with the switching operation of the three-way valve, so the cleaning work to remove solid air that has entered the piping system and frozen and stuck is only the switching operation of the three-way valve. It can be easily performed by limiting to the helium container side.

In the cryogenic container according to claim 6 of the present invention, a release valve provided in a piping system of a portion located outside the vacuum container connected from the helium container to the differential pressure type level gauge is a solenoid valve. Since the heater power supply circuit and the excitation circuit of the solenoid valve are interlocked with each other, the cleaning work can be simultaneously performed by the low pressure side piping system and the high pressure side piping system only by opening and closing the heater power supply.

In the cryogenic container according to claim 7 of the present invention, the discharge valve provided in the piping system located outside the vacuum container connected from the helium container to the differential pressure type level gauge is a solenoid valve, The solenoid valve opens after a lapse of a predetermined time after the heater power is turned on, and the heater power is opened and closed at the same time.Therefore, the solid-state air that enters the piping and freezes and sticks is vaporized, and then the release valve is released. It opens and is released.

[0022]

【Example】

Example 1. A first embodiment according to the present invention will be described with reference to FIGS. In the figure, 1-5, 7-9, 11-1
6 is the same as or has the same function as the conventional cryogenic container shown in FIGS. 17
Is a low-pressure side release valve mounted in a T-branch to a piping system located outside the vacuum container so that the gas in the low-pressure side piping system 4 can be appropriately discharged to the atmosphere, and 18 is a gas in the high-pressure side piping system 5. Is a high-pressure side discharge valve which is T-branched and attached to a piping system located outside the vacuum container so as to be appropriately discharged to the atmosphere. In this first embodiment, a low pressure side discharge valve 17 and a high pressure side discharge valve 18 are added to the low pressure side and high pressure side piping systems of the configuration of the conventional example shown in FIG.

In the first embodiment constructed as described above,
When the helium container 1 is in a negative pressure state due to a sudden change in atmospheric pressure or a sudden change in ambient temperature, or the invading air is cooled by liquid helium due to the diffusion phenomenon at the joint part of the piping system and the inside diameter of the piping system is cooled. The cleaning work for periodically removing the solid air frozen and adhered to the heater is performed by the switch 1 of the power source 15 of the heater 11 or 13 inserted in the low pressure side extraction pipe 4a or the high pressure side extraction pipe 5a, respectively.
6 is charged to heat the low-pressure side extraction pipe 4a or the high-pressure side extraction pipe 5a located in the vacuum container 3 to freeze and solidify the solid air to vaporize, and to release the low-pressure side discharge valve 17 or the high-pressure side discharge. The opening of the valve 18 for a predetermined time can be removed by a simple method of only switching the heater power supply and operating the discharge valve without dismantling the piping system.

Example 2. The second embodiment of the present invention is shown in FIGS. In the second embodiment of the present invention, the low-pressure side three-way valve 19 is provided in the low-pressure side piping system 4 and the high-pressure side piping system 5 is provided in the high pressure side three-way portion of the portion of the conventional example shown in FIG. The valve 20 is provided.

In this configuration, for each of the low-pressure side piping system 4 and the high-pressure side piping system 5, switching operation of the low-pressure side three-way valve 19 and power-on of the heater 11 or switching operation of the high-pressure side three-way valve 20 and heater 13 is performed. By turning on the power, the cleaning work of the low pressure side or high pressure side piping system can be easily performed without disassembling the piping system. As shown in FIG. 5, by using the three-way valve, the normal operation is in the A state, and the cleaning operation is in the B state so that the cryogenic container 1 side is opened.

Example 3. Next, a third embodiment of the present invention will be described. This third embodiment corresponds to each of the low pressure side discharge valve 17 and the high pressure side discharge valve 18 of the first embodiment, and the limit switches 21 and 22 shown by dotted lines in FIG.
The limit switch 21 or 22 operates in conjunction with the opening / closing operation of the low pressure side discharge valve 17 and the high pressure side discharge valve 18, and the heater 11 or 13 corresponding to the low pressure side discharge valve 17 or the high pressure side discharge valve 18, respectively. Power switch 16
Are automatically turned on and the respective release valves 17 or 18
The power switch 16 of the heater 11 or 13 is configured to be opened when the closing operation is performed.

With this structure, it is not necessary to open and close the power switch 16 of the heaters 11 and 13 during the cleaning work of the low pressure side and high pressure side piping systems 4 and 5, respectively, and the valves of the discharge valves 17 and 18 are eliminated. It can be performed only by the operation, and it is possible to avoid forgetting to turn off the heater power supply after the cleaning work.

Example 4. Next, a fourth embodiment of the present invention will be described. In the fourth embodiment, limit switches 23 and 24 shown by dotted lines in FIG. 5 are provided corresponding to the low pressure side three-way valve 19 and the high pressure side three-way valve 20 of the second embodiment, respectively. The limit switch 23 or 24 operates in conjunction with the switching operation of the high-pressure side three-way valve 20, and the power switch 16 of the heater 11 or 13 corresponding to the low-pressure side three-way valve 19 or the high-pressure side three-way valve 20 is automatically turned on. When the three-way valves 19 and 20 are closed, the power switch 16 of the heater 11 or 13 is opened.

With this construction, in addition to the effect of using the three-way valve of the second embodiment, the heater 11 during the cleaning work of the low pressure side and high pressure side piping systems 4 and 5 is performed.
Alternatively, the opening / closing operation of the power switch 16 of 13 is not necessary, and it can be performed only by the switching operation of the three-way valves 19 and 20, so that the heater 11 or 13 after the cleaning operation is performed.
It is possible to avoid forgetting to turn off the power switch 16.

Example 5. Next, a fifth embodiment of the present invention will be described. In the fifth embodiment, the low pressure side discharge valve 17 and the high pressure side discharge valve 18 of the first embodiment are electromagnetic valves, and FIG. 6 shows the configuration of the fifth embodiment corresponding to the first embodiment. Show. Reference numeral 25 is a low pressure side release solenoid valve, and 26 is a high pressure side release solenoid valve.

With this configuration, the low pressure side piping system 4
When the heater power is turned on for cleaning the high-pressure side piping system 5 and the low-voltage side and high-pressure side piping systems 4 and 5 corresponding to the first embodiment are released, the heater power source switch 16 is turned on. By
Since the release solenoid valves 25 and 26 are opened at the same time, the cleaning work can be easily performed only by opening and closing the heater power supply.

Example 6. Next, a sixth embodiment of the present invention will be described. The sixth embodiment is different from the fifth embodiment in that the electromagnetic solenoids 25, 26 are operated so that the release solenoid valves 25, 26 operate after a predetermined time has elapsed after the heaters have been turned on to the low pressure side and high pressure side piping systems 4, 5. A timer is provided in the valve circuit (not shown)
It is a thing.

With such a configuration, in the cleaning work, the heater power is first turned on to vaporize the solid air that has frozen and adhered inside the piping systems 4 and 5, and then the discharge solenoid valve 25,
Since 26 is opened, the helium gas is not discharged unnecessarily while the solid air is vaporized, and the cleaning operation can be performed only by operating the heater power supply switch.

[0034]

In the cryogenic container according to claim 1 of the present invention, a valve which is released when the heater is heated is provided in a portion of the pipe leading from the helium container to the outside of the vacuum container and located outside the vacuum container. Therefore, there is an effect that a cleaning operation for removing solid air that has entered the inside of the pipe and frozen and adhered can be easily performed only by switching the heater power supply and opening / closing the valve without disassembling the pipe.

The cryogenic container according to claim 2 of the present invention is
Since the low-pressure side piping system and the high-pressure side piping system connected from the helium container to the differential pressure level gauge were equipped with a release valve that is released when the heater is heated, solid air that has entered the piping system and frozen and stuck There is an effect that the cleaning work to be eliminated can be easily performed only by switching the heater power supply and opening / closing the discharge valve without disassembling the piping system.

The cryogenic container according to claim 3 of the present invention is a three-way valve which is released when the heater is heated to each of the low pressure side piping system and the high pressure side piping system connected from the helium container to the differential pressure level gauge. Since the cleaning work to remove the solid air that has entered the piping system and frozen and adhered does not dismantle the piping system, the frozen solid air that has frozen and adhered can be operated by switching the heater power supply and switching the three-way valve. There is an effect that the discharge time of each of them can be changed by switching between the side of the cryogenic container and the side of the differential pressure type liquid level gauge.

The cryogenic container according to claim 4 of the present invention discharges when the heater power is turned on in association with the opening operation of the discharge valve provided in the low pressure side piping system and the high pressure side piping system of claim 2. Since the heater power supply is opened by closing the valve, the cleaning work can be performed only by operating the discharge valve, and it is possible to avoid forgetting to turn off the heater power supply after the cleaning work is completed.

Further, in the cryogenic container according to claim 5 of the present invention, the heater power is turned on in conjunction with the switching operation of the three-way valves provided in the low pressure side piping system and the high pressure side piping system of claim 3. As a result, the heater power supply is opened when the discharge port of the three-way valve is closed, and cleaning work can be performed only by operating the three-way valve, and the discharge section of the piping system can be selected by switching the three-way valve. There is an effect that can be.

A cryogenic container according to a sixth aspect of the present invention uses the release valve of the second aspect as a solenoid valve, and corresponds to each of the low pressure side piping system or the high pressure side piping system in conjunction with turning on the heater power. Since the release solenoid valve is opened and closed, the cleaning operation can be performed only by operating the heater power supply.

According to a seventh aspect of the present invention, a cryogenic container is provided with a timer in the solenoid valve exciting circuit so that the release solenoid valve of the fifth aspect operates after a predetermined time has elapsed since the heater power was turned on. Therefore, the helium gas wasted in vain until the solid air that freezes and solidifies without vaporizing the solenoid valve for a predetermined time until the temperature of the piping system located in the vacuum container of the piping system rises. Has the effect of avoiding the release of.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a cryogenic container according to a first embodiment of the present invention.

FIG. 2 is a partially enlarged view of a connecting portion between the piping system of FIG. 1 and a vacuum container.

FIG. 3 is a configuration diagram of a cryogenic container according to a second embodiment of the present invention.

FIG. 4 is a partially enlarged view of a connecting portion between the piping system of FIG. 3 and a vacuum container.

5 is an explanatory diagram illustrating a switching operation of the three-way valve in FIG.

FIG. 6 is a layout configuration diagram of a piping system according to a fifth embodiment of the present invention.

FIG. 7 is a configuration diagram of a conventional cryogenic container.

FIG. 8 is a partially enlarged view of a connecting portion between the piping system of FIG. 7 and a vacuum container.

[Explanation of symbols]

 1 Helium container 3 Vacuum container 4 Low pressure side piping system 5 High pressure side piping system 7 Differential pressure type liquid level gauge 11 Heater 13 Heater 17 Low pressure side discharge valve 18 High pressure side discharge valve 19 Low pressure side three way valve 20 High pressure side three way valve 21 Limit switch 22 Limit switch 23 Limit switch 24 Limit switch 25 Low pressure side solenoid valve 26 High pressure side solenoid valve

Claims (7)

[Claims] 1. A helium container containing liquid helium, a vacuum container containing the helium container, the inside of which is maintained in a vacuum, a pipe extending from the helium container to the outside through the vacuum container wall, A pole provided with a heater inserted into an inner diameter portion of a portion of the pipe located in the vacuum container, and a valve released when the heater is heated is provided in a portion of the pipe located outside the vacuum container. Cryogenic container. 2. A helium container containing liquid helium, a vacuum container containing the helium container, the inside of which is maintained in a vacuum, a helium container penetrating through the vacuum container wall from the top of the helium container Low-pressure side piping system that derives pressure to the outside, to the high-pressure side piping system, low-pressure side piping system and high-pressure side piping system that penetrates the vacuum container wall from the helium container bottom to derive the pressure of the helium container bottom to the outside Connected, by the difference in the internal pressure of each, the differential pressure level gauge for detecting the liquid level of liquid helium in the helium container, the inner diameter of the portion of the low-pressure side piping system and the high-pressure side piping system located in the vacuum container When the heater is heated, the heater is inserted into each of the parts, and the heater is heated to the parts of the low pressure side piping system and the high pressure side piping system that are located outside the vacuum container. A cryogenic container provided with a discharge valve for 3. A helium container containing liquid helium, a vacuum container containing the helium container, the inside of which is maintained in a vacuum, and a helium container having a top portion which penetrates the vacuum container wall from the top portion of the helium container Low-pressure side piping system for deriving pressure to the outside, to the high-pressure side piping system, low-pressure side piping system and high-pressure side piping system for deriving the pressure of the helium container bottom from the helium container bottom through the vacuum container wall to the outside Connected, by the difference in the internal pressure of each, the differential pressure level gauge for detecting the liquid level of liquid helium in the helium container, the inner diameter of the portion of the low-pressure side piping system and the high-pressure side piping system located in the vacuum container When the heater is heated, the heater is inserted into each of the parts, and the heater is heated to the parts of the low pressure side piping system and the high pressure side piping system that are located outside the vacuum container. A cryogenic container characterized by having a three-way valve. 4. The cryogenic container according to claim 2, wherein the power supply for supplying electric power to the heater is controlled to be closed by the opening operation of the discharge valve and controlled to be opened by the closing operation. 5. The cryogenic container according to claim 3, wherein the power source for supplying power to the heater is controlled to be closed by a discharging operation of the three-way valve and opened by a closing operation. 6. A discharge valve provided in the piping system is a solenoid valve,
The cryogenic container according to claim 2, wherein the solenoid valve is controlled to be opened by turning on a power source for supplying power to the heater, and the solenoid valve is closed when the heater is opened. 7. A discharge valve provided in the piping system is a solenoid valve,
The power supply for supplying power to the heater is turned on, and a solenoid valve is opened after a lapse of a predetermined time, and a control is performed to close the solenoid valve when the heater power supply is opened. The cryogenic container described.