JP2021098516A - Space environment testing device and liquid nitrogen recovery method of the same - Google Patents

Abstract

To provide a space environment testing device which can effectively recover liquid nitrogen without adding facilities such as a pump, and to provide a liquid nitrogen recovery method of the space environment testing device.SOLUTION: A space environment testing device 31 according to the invention includes a shroud 37 and a head tank 39, and cools the shroud 37 in a free boiling method to turn an interior of a vacuum space 33 into a state simulating cold darkness of a space environment and conduct a test. The space environment testing device 31 has: a first supply pipe 41 which connects a liquid nitrogen tank 35 with a head tank 39; a second supply pipe 43 which connects the head tank 39 with the shroud 37; a discharge pipe 45 which connects the shroud 37 with the head tank 39; a recovery pipe 47 which connects the second supply pipe 43 with the first supply pipe 41; an on-off valve 49 which is provided at the recovery pipe 47; and a gas nitrogen supply part 51 which is provided at the head tank 39.SELECTED DRAWING: Figure 3

Description

The present invention is a space environment test apparatus for recovering liquid nitrogen used for cooling the shroud, and a liquid nitrogen recovery method for the space environment test apparatus.

The space environment test device is a device for making the inside of a vacuum vessel close to the space environment and performing tests such as operation confirmation on the earth before sending a test body such as an artificial satellite to space.
In the space environment test equipment, generally, a heat absorption wall called a shroud is installed inside the vacuum vessel, and a low temperature refrigerant such as liquid nitrogen is supplied to the shroud to reduce the temperature (100K when liquid nitrogen is used). By cooling to (below), it is possible to create a state in which the cold and darkness close to the space environment is simulated in the vacuum vessel.
As a method of cooling the shroud in the conventional space environment test apparatus, there are a one-through type (see FIG. 5) and a free boiling type (see FIG. 6) disclosed in Patent Document 1.

In the one-through type space environment test device 71 shown in FIG. 5, liquid nitrogen is supplied from the liquid nitrogen supply device 5 to the shroud 7 in the vacuum vessel 3 via the supply pipe 11 to cool the shroud 7, and then the shroud 7 is cooled. The mixed fluid of liquid nitrogen and gaseous nitrogen is discharged to the discharge reservoir 9 via the discharge pipe 13. The discharged gaseous nitrogen is released to the atmosphere through the gaseous nitrogen release pipe 21 and the gaseous nitrogen release valve 23 provided in the liquid discharge reservoir 9, whereas the discharged liquid nitrogen is stored in the discharge reservoir 9. Be done.
Then, after the test is completed, the liquid nitrogen stored in the liquid discharge reservoir 9 can be recovered in the liquid nitrogen supply device 5 by being transferred in the recovery pipe 75 by the pump 73.

Further, in the free boiling type space environment test apparatus 81 shown in FIG. 6, the liquid nitrogen supplied from the liquid nitrogen storage tank 35 via the first supply pipe 41 is more than the shroud 37 installed in the vacuum vessel 33. It is temporarily stored in a head tank 39 installed above in the vertical direction, and the temporarily stored liquid nitrogen is supplied to the shroud 37 via the second supply pipe 43 by its own weight to be cooled. After cooling the shroud 37, the mixed fluid of liquid nitrogen and gaseous nitrogen is discharged to the head tank 39 via the discharge pipe 45. The discharged gaseous nitrogen is released to the atmosphere through the gaseous nitrogen release pipe 53 and the gaseous nitrogen release valve 55, while the discharged liquid nitrogen is stored in the head tank 39.
After the test is completed, the liquid nitrogen stored in the head tank 39 can be recovered in the liquid nitrogen storage tank 35 by a pump and a recovery pipe (not shown) in the same manner as the one-through type described above.

Japanese Unexamined Patent Publication No. 7-165200

As mentioned above, in the conventional space environment test equipment, in order to recover the liquid nitrogen remaining in the liquid discharge reservoir or the head tank after the test is completed, a pump for transferring the liquid nitrogen is required, and the pump There was a problem that power was required.
Further, in order to recover the liquid nitrogen remaining in the shroud in the one-through type space environment test apparatus, the liquid nitrogen is discharged from the shroud into the liquid discharge reservoir, and the liquid nitrogen stored in the liquid discharge reservoir is pumped to the liquid nitrogen. A method of transferring to a supply device is conceivable, but if the liquid discharge reservoir is not insulated, there is a lot of heat entering in the process of discharging and recovering liquid nitrogen, and the amount of liquid nitrogen evaporated increases, so the amount that can be recovered There was a problem that it would be reduced. This problem was also the same in the free-boiling type space environment test device using the head tank.

The present invention has been made to solve the above problems, and is a space environment test apparatus capable of effectively recovering liquid nitrogen without adding equipment such as a pump, and the space environment test. It is an object of the present invention to provide a method for recovering liquid nitrogen of an apparatus.

(1) The space environment test apparatus according to the present invention is provided in a vacuum vessel, and a shroud that is cooled by receiving the supply of liquid nitrogen from the liquid nitrogen supply device and a discharge liquid that stores the liquid nitrogen discharged from the shroud. A reservoir is provided, and the shroud is cooled in a one-through manner to simulate the cold and darkness of the space environment in the vacuum vessel for testing. The liquid nitrogen supply device and the shroud are connected to each other. A supply pipe that supplies liquid nitrogen to the shroud, a discharge pipe that connects the shroud and the liquid discharge reservoir, and discharges the liquid nitrogen that has cooled the shroud to the liquid discharge reservoir, and the liquid discharge reservoir. A recovery pipe that connects the supply pipe and collects the liquid nitrogen stored in the liquid discharge reservoir to the liquid nitrogen supply device, an on-off valve provided in the recovery pipe, and the liquid discharge reservoir is pressurized. It has a gas nitrogen supply unit that supplies the gas nitrogen, and with the on-off valve open, pressurized gas nitrogen is supplied to the gas nitrogen supply unit, and the liquid nitrogen in the liquid discharge reservoir is supplied. The liquid nitrogen in the shroud communicating with the liquid discharge reservoir is pumped to the supply pipe side while being pumped to the supply pipe side via the recovery pipe, and the pumped liquid nitrogen is recovered to the liquid nitrogen supply device. It is characterized by doing so.

(2) The space environment test apparatus according to the present invention is provided in a vacuum vessel, and a shroud that is cooled by receiving the supply of liquid nitrogen from the liquid nitrogen supply device and a discharge liquid that stores the liquid nitrogen discharged from the shroud. By providing a reservoir and cooling the shroud in a one-through manner, a test is conducted in a state in which the inside of the vacuum vessel is simulated in the cold and dark of the space environment, and the liquid nitrogen supply device and the shroud are subjected to a test. A supply pipe that connects and supplies liquid nitrogen to the shroud, a discharge pipe that connects the shroud and the liquid discharge reservoir, and discharges the liquid nitrogen that has cooled the shroud to the liquid discharge reservoir, and the liquid discharge reservoir. And the supply pipe are connected to each other, and the liquid nitrogen stored in the liquid discharge reservoir is collected in the liquid nitrogen supply device, the on-off valve provided in the recovery pipe, and the liquid in the liquid discharge reservoir. It has a heating means for heating and vaporizing nitrogen, and in a state where the on-off valve is open, the liquid nitrogen in the liquid discharge reservoir is heated and vaporized by the heating means to vaporize the inside of the liquid discharge reservoir. Pressurized, the liquid nitrogen in the liquid discharge reservoir is pressure-fed to the supply pipe side via the recovery pipe, and the liquid nitrogen in the shroud communicating with the liquid discharge reservoir is pressure-fed to the supply pipe side. It is characterized in that the pumped liquid nitrogen is recovered in the liquid nitrogen supply device.

(3) The above-mentioned item (1) or (2) is characterized in that a thermometer is installed in the supply pipe.

(4) In any of the above (1) to (3), the recovery pipe is characterized in that the lowermost part of the liquid discharge reservoir and the lowermost part of the supply pipe are connected. is there.

(5) The space environment test apparatus according to the present invention is provided in a vacuum vessel and uses a shroud that is cooled by receiving the supply of liquid nitrogen from the liquid nitrogen supply device and the liquid nitrogen supplied from the liquid nitrogen supply device. A head tank that temporarily stores and supplies the temporarily stored liquid nitrogen to the shroud and stores the liquid nitrogen discharged from the shroud is provided, and the shroud is cooled by a free-boiling method in the vacuum vessel. The test is conducted in a state simulating the cold and darkness of the space environment. The liquid nitrogen supply device is connected to the head tank, and the liquid nitrogen supply device supplies liquid nitrogen to the head tank. 1 The supply pipe is connected to the head tank and the shroud, and the second supply pipe that supplies liquid nitrogen temporarily stored in the head tank to the shroud is connected to the shroud and the head tank to connect the shroud. The second supply pipe and the first supply pipe are connected to the discharge pipe that discharges the cooled liquid nitrogen to the head tank, and the liquid nitrogen in the head tank and the shroud is collected in the liquid nitrogen supply device. With the recovery pipe to be used, an on-off valve provided in the recovery pipe, and a liquid nitrogen supply unit for supplying pressurized nitrogen into the head tank, the on-off valve is open. Pressurized gaseous nitrogen is supplied to the gaseous nitrogen supply unit, and liquid nitrogen in the head tank and in the shroud communicating with the head tank is supplied to the first supply pipe via the second supply pipe and the recovery pipe. It is characterized in that it is pumped to the side and the pumped liquid nitrogen is recovered in the liquid nitrogen supply device.

(6) The space environment test apparatus according to the present invention is provided in a vacuum vessel and uses a shroud that is cooled by receiving the supply of liquid nitrogen from the liquid nitrogen supply device and the liquid nitrogen supplied from the liquid nitrogen supply device. The vacuum container is provided with a head tank that temporarily stores and supplies the temporarily stored liquid nitrogen to the shroud and stores the liquid nitrogen discharged from the shroud, and cools the shroud in a free boiling manner. The test is conducted in a state simulating the cold and darkness of the space environment, in which the liquid nitrogen supply device and the head tank are connected and liquid nitrogen is supplied from the liquid nitrogen supply device to the head tank. The first supply pipe is connected to the head tank and the shroud, and the second supply pipe that supplies liquid nitrogen temporarily stored in the head tank to the shroud is connected to the shroud and the head tank. The discharge pipe that discharges the liquid nitrogen that cooled the shroud to the head tank is connected to the second supply pipe and the first supply pipe, and the liquid nitrogen in the head tank and the shroud is transferred to the liquid nitrogen supply device. The heating means has a recovery pipe for recovery, an on-off valve provided in the recovery pipe, and a heating means for heating and vaporizing liquid nitrogen in the head tank. With the on-off valve open, the heating means The liquid nitrogen in the head tank is heated and vaporized to pressurize the inside of the head tank, and the liquid nitrogen in the head tank and the shroud communicating with the head tank is supplied to the second supply pipe and the recovery pipe. It is characterized in that it is pumped to the first supply pipe side via the above and the liquid nitrogen that has been pumped is recovered in the liquid nitrogen supply device.

(7) In the one described in (5) or (6) above, the thermometer is installed in the first supply pipe or the recovery pipe.

(8) In any of the above (5) to (7), the recovery pipe is characterized in that the lowermost portion of the second supply pipe and the lowermost portion of the first supply pipe are connected. To do.

(9) The liquid nitrogen recovery method of the space environment test apparatus according to the present invention includes a shroud provided in a vacuum vessel and cooled by receiving the supply of liquid nitrogen via a supply pipe connected to the liquid nitrogen supply apparatus. A space environment test in which the inside of the vacuum vessel is simulated in the cold and dark of the space environment by cooling the shroud in a one-through manner with a discharge reservoir for storing the liquid nitrogen discharged from the shroud. The liquid nitrogen in the apparatus is recovered, and the liquid nitrogen reservoir and the supply pipe are connected via a recovery pipe, and pressurized gaseous nitrogen is supplied to the liquid discharge reservoir to be inside the liquid discharge reservoir. By pressurizing, the liquid nitrogen in the liquid discharge reservoir is pumped to the supply pipe side via the recovery pipe, and the liquid nitrogen in the shroud communicating with the liquid discharge reservoir is sent to the supply pipe side. It is characterized in that it is pumped and the pumped liquid nitrogen is recovered in the liquid nitrogen supply device.

(10) The liquid nitrogen recovery method of the space environment test apparatus according to the present invention includes a shroud provided in a vacuum vessel and cooled by receiving the supply of liquid nitrogen via a supply pipe connected to the liquid nitrogen supply apparatus. A space environment test in which the inside of the vacuum vessel is simulated in the cold and dark of the space environment by cooling the shroud in a one-through manner with a discharge reservoir for storing the liquid nitrogen discharged from the shroud. The liquid nitrogen in the apparatus is recovered, and the liquid nitrogen in the liquid discharge reservoir is connected to the supply pipe via a recovery pipe, and the liquid nitrogen in the liquid discharge reservoir is heated and vaporized to vaporize the liquid nitrogen in the liquid discharge reservoir. By pressurizing the inside, the liquid nitrogen in the liquid discharge reservoir is pressure-fed to the supply pipe side, and the liquid nitrogen in the shroud communicating with the liquid discharge reservoir is pressure-fed to the supply pipe side. It is characterized in that the liquid nitrogen produced is recovered in the liquid nitrogen supply device.

(11) The liquid nitrogen recovery method of the space environment test apparatus according to the present invention includes a shroud provided in a vacuum vessel and cooled by receiving the supply of liquid nitrogen from the liquid nitrogen supply apparatus, and the liquid nitrogen supply apparatus. (1) A head tank that temporarily stores liquid nitrogen supplied through a supply pipe, supplies the temporarily stored liquid nitrogen to the shroud via a second supply pipe, and stores liquid nitrogen discharged from the shroud. By cooling the shroud in a free-boiling manner, liquid nitrogen in a space environment test apparatus that conducts a test in a state that simulates the cold and darkness of the space environment is recovered. By connecting the second supply pipe and the first supply pipe via a recovery pipe and supplying pressurized nitrogen to the head tank to pressurize the inside of the head tank, the inside of the head tank and the inside of the head tank are pressed. Liquid nitrogen in the shroud communicating with the head tank is pumped to the first supply pipe side via the second supply pipe and the recovery pipe, and the pumped liquid nitrogen is recovered to the liquid nitrogen supply device. It is characterized by.

(12) The liquid nitrogen recovery method of the space environment test apparatus according to the present invention includes a shroud provided in a vacuum vessel and cooled by receiving the supply of liquid nitrogen from the liquid nitrogen supply apparatus, and the liquid nitrogen supply apparatus. (1) A head tank that temporarily stores liquid nitrogen supplied through a supply pipe, supplies the temporarily stored liquid nitrogen to the shroud via a second supply pipe, and stores liquid nitrogen discharged from the shroud. By cooling the shroud in a free-boiling manner, liquid nitrogen in a space environment test apparatus that conducts a test in a state that simulates the cold and darkness of the space environment is recovered. By connecting the second supply pipe and the first supply pipe via a recovery pipe and pressurizing the inside of the head tank by heating and vaporizing the liquid nitrogen in the head tank, the inside of the head tank and the inside of the head tank Liquid nitrogen in the shroud communicating with the head tank is pumped to the first supply pipe side via the second supply pipe and the recovery pipe, and the pumped liquid nitrogen is recovered to the liquid nitrogen supply device. It is characterized by.

In the space environment test apparatus of the present invention, pressurized gaseous nitrogen is supplied to the gaseous nitrogen supply unit, and the liquid nitrogen in the liquid discharge reservoir is pumped to the supply pipe side via the recovery pipe, and the liquid discharge reservoir is described. By pumping the liquid nitrogen in the shroud communicating with the gas to the supply pipe side and recovering the pumped liquid nitrogen to the liquid nitrogen supply device, the liquid nitrogen can be effectively recovered without adding equipment such as a pump. be able to.

It is a figure explaining the state of recovering liquid nitrogen in the one-through type space environment test apparatus which concerns on Embodiment 1 of this invention. It is a figure explaining the state of supplying liquid nitrogen and cooling in the one-through type space environment test apparatus which concerns on Embodiment 1 of this invention. It is a figure explaining the state of recovering liquid nitrogen in the free-boiling type space environment test apparatus which concerns on Embodiment 2 of this invention. It is a figure explaining the state of supplying liquid nitrogen and cooling in the free-boiling type space environment test apparatus which concerns on Embodiment 2 of this invention. It is a figure explaining the conventional one-through type space environment test apparatus. It is a figure explaining the conventional free-boiling type space environment test apparatus.

[Embodiment 1]
<Space environment test equipment>
As shown in FIG. 1, the space environment test apparatus 1 according to the first embodiment of the present invention is provided with a shroud 7 provided in the vacuum vessel 3 and cooled by receiving the supply of liquid nitrogen from the liquid nitrogen supply apparatus 5. , A discharge reservoir 9 for storing liquid nitrogen discharged from the shroud 7 is provided, and the inside of the vacuum vessel 3 is simulated in the cold and dark state of the space environment by cooling the shroud 7 in a one-through manner. It is provided with a supply pipe 11, a discharge pipe 13, a recovery pipe 15, an on-off valve 17, and a liquid nitrogen supply unit 19.

Hereinafter, this implementation will be based on FIG. 1 showing a state when liquid nitrogen is recovered from the space environment test device 1 and FIG. 2 showing a state where the shroud 7 is cooled to perform a test with the space environment test device 1. Each configuration of the space environment test apparatus 1 according to the first embodiment will be described. In the legends of FIGS. 1 and 2, "valve open" means that the valve is open (shown in white), and "valve closed" means that the valve is closed (painted in black). (Illustrated) is shown (the same applies to FIGS. 3 and 4 of the second embodiment described later).

≪Vacuum container≫
The vacuum container 3 is for simulating the space environment inside, and various test bodies such as artificial satellites are installed. Then, the vacuum vessel 3 is exhausted by a vacuum pump (not shown) in order to create a high vacuum inside.

≪Liquid nitrogen supply device≫
The liquid nitrogen supply device 5 supplies liquid nitrogen to the shroud 7 to cool it when conducting a test using the space environment test device 1 (see FIG. 2), and recovers the liquid nitrogen after the test is completed. At this time, the liquid nitrogen in the liquid discharge reservoir 9 and the shroud 7 is recovered (see FIG. 1). The liquid nitrogen supply device 5 may be any device that can supply and recover liquid nitrogen at a predetermined supply pressure, and for example, a vacuum-insulated liquid nitrogen storage tank can be used.

Further, an appropriate liquid nitrogen supply device 5 is appropriately selected depending on the amount, pressure, and the like of liquid nitrogen required for cooling the space environment test device 1.
For example, in the relatively small space environment test device 1, a small portable liquid nitrogen supply device or the like may be used as the liquid nitrogen supply device 5, and in the relatively large space environment test device 1, the liquid nitrogen supply device 5 is used. A large liquid nitrogen storage tank or the like may be used as the above.
However, the effect of the present invention is not affected by the difference in the type of the liquid nitrogen supply device 5.

≪Shroud≫
The shroud 7 is supplied with liquid nitrogen and cooled to a predetermined temperature to create a state in which the cold and darkness of the space environment is simulated in the vacuum vessel 3. The shroud 7 can be cooled to 100 K or less by supplying liquid nitrogen, and the temperature of the shroud 7 can be adjusted by the supply amount and supply pressure of liquid nitrogen. A part of the liquid nitrogen supplied to the shroud 7 is vaporized in the process of cooling the shroud 7 to become gaseous nitrogen.

≪Liquid discharge reservoir≫
The liquid discharge reservoir 9 discharges liquid nitrogen or a mixed fluid of liquid nitrogen and gaseous nitrogen after being supplied to the shroud 7 from the liquid nitrogen supply device 5 and cooled, and stores the discharged liquid nitrogen.
The liquid discharge reservoir 9 is provided with a gas nitrogen discharge pipe 21 and a gas nitrogen release valve 23 for releasing the gaseous nitrogen discharged from the shroud 7 into the atmosphere.

≪Supply piping≫
The supply pipe 11 connects the liquid nitrogen supply device 5 and the shroud 7 and supplies liquid nitrogen to the shroud 7, and includes supply pipes 11a and 11b.

≪Discharge piping≫
The discharge pipe 13 is provided to connect the shroud 7 and the liquid discharge reservoir 9 and discharge the mixed fluid of liquid nitrogen and gaseous nitrogen after cooling the shroud 7 to the liquid discharge reservoir 9. Since the shroud 7 and the liquid discharge reservoir 9 are connected by the discharge pipe 13, the shroud 7 and the liquid discharge reservoir 9 are communicated with each other while maintaining airtightness.

≪Recovery piping≫
The recovery pipe 15 is for connecting the liquid discharge reservoir 9 and the supply pipe 11 and collecting the liquid nitrogen stored in the liquid discharge reservoir 9 in the liquid nitrogen supply device 5.
In order to efficiently recover the liquid nitrogen stored in the liquid discharge reservoir 9, the recovery pipe 15 is preferably one whose end is connected to the lowermost part of the liquid discharge reservoir 9.

≪Opening valve≫
The on-off valve 17 is provided in the recovery pipe 15, and the on-off valve 17 is in a closed state when liquid nitrogen is supplied to the shroud 7 to cool it (see FIG. 2), and the inside of the liquid discharge reservoir 9 is provided. When the liquid nitrogen in the above is recovered, the on-off valve 17 is in an open state (see FIG. 1).

≪Gaseous nitrogen supply part≫
The gaseous nitrogen supply unit 19 is provided in the liquid discharge reservoir 9 and supplies pressurized nitrogen to the liquid discharge reservoir 9, and as shown in FIG. 1, the gaseous nitrogen supply pipe 19a and the gaseous nitrogen supply A valve 19b can be used.

The gaseous nitrogen supply unit 19 can connect a nitrogen cylinder (not shown) or the like to the gaseous nitrogen supply pipe 19a. Then, when the inside of the liquid discharge reservoir 9 is pressurized, the gas nitrogen release valve 23 is closed and the gas nitrogen supply valve 19b is opened, and the gas nitrogen pressurized from the nitrogen cylinder is discharged. By supplying to the reservoir 9, the inside of the discharge reservoir 9 is pressurized. When supplying gaseous nitrogen by the gaseous nitrogen supply unit 19, it is desirable that the opening degree of the gaseous nitrogen supply valve 19b can be controlled so that the pressure inside the liquid discharge reservoir 9 becomes constant.

The gas nitrogen supply unit 19 may have the gas nitrogen supply pipe 19a connected to the gas nitrogen release pipe 21, and pressurizes the liquid discharge reservoir 9 with the gas nitrogen release valve 23 closed. Any material may be used as long as it can supply gaseous nitrogen and pressurize the inside of the discharge reservoir 9.

<Liquid nitrogen recovery method>
Next, the liquid nitrogen recovery method in the space environment test device 1 according to the first embodiment will be described together with the operation of the space environment test device 1 shown in FIGS. 1 and 2.

First, liquid nitrogen is supplied from the liquid nitrogen supply device 5 to the shroud 7 via the supply pipes 11a and 11b at a predetermined supply pressure to cool the shroud 7 and perform a test (see FIG. 2).
During the cooling operation, the shroud 7 is cooled by keeping the on-off valve 17 provided in the recovery pipe 15 and the gas nitrogen supply valve 19b of the gas nitrogen supply unit 19 closed and the gas nitrogen release valve 23 open. The mixed fluid of liquid nitrogen and gaseous nitrogen is discharged from the discharge pipe 13 to the discharge reservoir 9. Then, while the discharged liquid nitrogen is stored in the liquid discharge reservoir 9, the discharged gas nitrogen is discharged to the atmosphere from the gas nitrogen release pipe 21 via the gas nitrogen release valve 23.

Then, when the cooling operation of the shroud 7 is completed to recover the liquid nitrogen, the supply of the liquid nitrogen from the liquid nitrogen supply device 5 is stopped, and then the on-off valve 17 is opened and the gas nitrogen release valve 23 is closed. (See Fig. 1). Next, a gas nitrogen cylinder is connected to the gas nitrogen supply pipe 19a, the gas nitrogen supply valve 19b is opened, and pressurized nitrogen is supplied from the gas nitrogen supply unit 19.

In this way, by supplying gaseous nitrogen to the liquid discharge reservoir 9 and applying pressure, a reverse pressure is applied to the liquid nitrogen stored in the liquid discharge reservoir 9, and the liquid nitrogen is supplied through the recovery pipe 15 and the on-off valve 17. It is pumped to the pipe 11a. At the same time, a reverse pressure is also applied to the liquid nitrogen stored in the shroud 7 communicating with the discharge reservoir 9 via the discharge pipe 13, and the liquid nitrogen is pressure-fed to the supply pipe 11a through the supply pipe 11b. Then, the liquid nitrogen pumped to the supply pipe 11a is collected in the liquid nitrogen supply device 5 through the supply pipe 11a.

The supply pressure of the gaseous nitrogen supplied to the gaseous nitrogen supply unit 19 may be set higher than the supply pressure of the liquid nitrogen supplied from the liquid nitrogen supply device 5 during the cooling operation, and the liquid nitrogen from the liquid nitrogen supply device 5 may be set. When the supply pressure of the above is 0.3 MPaG, the supply pressure of the gaseous nitrogen supplied to the gaseous nitrogen supply unit 19 may be about 0.4 to 0.6 MPaG.

As described above, according to the liquid nitrogen recovery method of the space environment test device 1 and the space environment test device 1 according to the first embodiment, the one-through cooling space environment test device does not use additional equipment such as a pump. By supplying pressurized gaseous nitrogen to the liquid nitrogen reservoir 9, the liquid nitrogen of the liquid discharge reservoir 9 and the shroud 7 is pumped to the supply pipe 11 side, and the pumped liquid nitrogen is collected in the liquid nitrogen supply device 5. can do. Further, since the inside of the supply pipe 11 used for cooling the shroud 7 is pumped, the influence of heat entering from the outside in the process of recovering liquid nitrogen is small, and the amount of liquid nitrogen vaporized can be suppressed. Can be done.

In addition, as another aspect of the liquid nitrogen recovery method of the space environment test apparatus 1 and the space environment test apparatus 1 according to the first embodiment, instead of the gaseous nitrogen supply unit 19, the liquid discharge reservoir 9 is heated by a heating means (not shown). None) may be provided.

In this case, the inside of the liquid discharge reservoir 9 is pressurized by vaporizing a part of the liquid nitrogen stored in the liquid discharge reservoir 9 with the gaseous nitrogen release valve 23 closed by a heating means, and the liquid nitrogen reservoir 9 is pressurized. And the liquid nitrogen of the shroud 7 can be pressure-fed to the supply pipe 11 side. As the heating means, a heater that heats liquid nitrogen can be used, and by controlling the output of the heater, the liquid discharge reservoir 9 can be pressurized to a predetermined pressure (for example, 0.4 to 0.6 MPaG) to be constant.

Further, in the space environment test apparatus 1 according to the first embodiment, it is difficult to directly grasp in which part of the pipes the liquid nitrogen is present when recovering the liquid nitrogen. Therefore, a thermometer 25 is provided in the supply pipe 11, the temperature of the liquid nitrogen to be pumped is measured, and when the measured temperature tends to rise, the liquid nitrogen is present in the shroud 7, the discharge reservoir 9, and the recovery pipe 15. It is possible to presume that it will not, and stop the recovery of liquid nitrogen.

That is, when the pumped liquid nitrogen flows through the supply pipe 11, the temperature measured by the thermometer 25 is about the same as that of the pumped liquid nitrogen, whereas the shroud 7 and the liquid discharge reservoir 9 have the same temperature. When liquid nitrogen is recovered and the gaseous nitrogen supplied from the gaseous nitrogen supply unit 19 flows into the supply pipe 11, the temperature becomes about the same as that of the gaseous nitrogen measured by the thermometer 25, and the temperature of the recovered liquid nitrogen. Because it will be higher than.

Here, as shown in FIGS. 1 and 2, the thermometer 25 is closer to the liquid nitrogen supply device 5 than the position where the recovery pipe 15 connected to the liquid discharge reservoir 9 and the supply pipe 11b connected to the shroud 7 are connected. It is preferably installed in the supply pipe 11a.

Further, in the space environment test apparatus 1 according to the first embodiment, it is desirable to install the recovery pipe 15 so as to connect the lowermost part of the liquid discharge reservoir 9 and the lowermost part of the supply pipe 11. As a result, when the inside of the liquid discharge reservoir 9 is pressurized and the liquid nitrogen is pumped, the liquid nitrogen is transferred to the supply pipe 11 side through the lowermost part in the vertical direction in the space environment test apparatus 1, so that the liquid nitrogen is piped. It can be recovered in the liquid nitrogen supply device 5 without leaving it in the class.

[Embodiment 2]
<Space environment test equipment>
As shown in FIG. 3, the space environment test apparatus 31 according to the second embodiment of the present invention includes a shroud 37 provided in the vacuum vessel 33 and cooled by receiving the supply of liquid nitrogen from the liquid nitrogen storage tank 35. The shroud 37 is provided with a head tank 39 for temporarily storing the liquid nitrogen supplied from the liquid nitrogen storage tank 35, supplying the temporarily stored liquid nitrogen to the shroud 37, and storing the liquid nitrogen discharged from the shroud 37. A test is conducted in a state in which the inside of the vacuum vessel 33 is simulated in the cold and dark of the space environment by cooling by a free boiling method, and the first supply pipe 41 connecting the liquid nitrogen storage tank 35 and the head tank 39 is used. , A second supply pipe 43 connecting the head tank 39 and the shroud 37, a discharge pipe 45 connecting the shroud 37 and the head tank 39, and a recovery pipe connecting the second supply pipe 43 and the first supply pipe 41. It has 47, an on-off valve 49 provided in the recovery pipe 47, and a liquid nitrogen supply unit 51 provided in the head tank 39.

Hereinafter, this implementation is based on FIG. 3 showing a state when liquid nitrogen is recovered by the space environment test device 31 and FIG. 4 showing a state in which the shroud 37 is cooled for testing by the space environment test device 31. Each configuration of the space environment test apparatus 31 according to the second embodiment will be described. Since the vacuum container 33 is the same as the vacuum container 3 in the above-described first embodiment, the description thereof will be omitted.

≪Liquid nitrogen storage tank≫
The liquid nitrogen storage tank 35 is a liquid nitrogen supply device that supplies and cools liquid nitrogen to the shroud 37 when conducting a test using the space environment test device 31, and is a liquid nitrogen supply device that cools the shroud 37 when the test is completed and the liquid nitrogen is recovered. , The liquid nitrogen of the head tank 39 and the shroud 37 is recovered in the liquid nitrogen storage tank 35 (see FIG. 3).

The liquid nitrogen storage tank 35 may be capable of supplying and recovering liquid nitrogen at a predetermined supply pressure, and liquid nitrogen is stored inside a vacuum-insulated double-wall structure. The liquid nitrogen storage tank 35 according to the second embodiment has a liquid nitrogen storage amount of 50,000 L class and a supply pressure of 0.3 MPaG, but the size and supply pressure of the liquid nitrogen storage tank 35 may be appropriately selected.

In the second embodiment, the liquid nitrogen storage tank 35 is used as the liquid nitrogen supply device, but the amount, pressure, etc. of the liquid nitrogen required for cooling the space environment test device 31 are the same as in the above-described first embodiment. The appropriate liquid nitrogen supply device is appropriately selected.

≪Shroud≫
Similar to the shroud 7 in the first embodiment, the shroud 37 simulates the cold and darkness of the space environment in the vacuum vessel 33 by being supplied with liquid nitrogen and cooled to a predetermined temperature (for example, 100 K or less). It is a state.
As the shroud 37 according to the second embodiment, an example of a shroud 37 made of aluminum and having a stored amount of liquid nitrogen of 9000 L can be exemplified. However, the material of the shroud 37 may be any material that can maintain a low temperature of about 100 K, and the amount of liquid stored may be appropriately set according to the size and heat load of the vacuum container 33 in which the shroud 37 is installed.

≪Head tank≫
The head tank 39 temporarily stores the liquid nitrogen supplied from the liquid nitrogen storage tank 35, supplies the temporarily stored liquid nitrogen to the shroud 37, and stores the liquid nitrogen discharged from the shroud 37. It is installed vertically above 37.

As will be described later, the head tank 39 is provided with a liquid level gauge (not shown) in order to control the liquid level height of the temporarily stored liquid nitrogen. It is desirable that the inside of the head tank 39 is opened to the atmosphere via the gas nitrogen discharge pipe 53 and the gas nitrogen release valve 55.

The head tank 39 according to the second embodiment is made of stainless steel and has a liquid nitrogen storage amount of 1000 L, but the material and the liquid storage amount of the head tank 39 can be appropriately selected.

≪First supply piping≫
The first supply pipe 41 connects the liquid nitrogen storage tank 35 and the head tank 39, and supplies liquid nitrogen from the liquid nitrogen storage tank 35 to the head tank 39. In FIGS. 3 and 4, the first supply pipe 41 is used. It consists of 41a and 41b.

Further, the first supply pipe 41 is provided with a liquid level control valve 57 that opens and closes according to the liquid level height of the liquid nitrogen temporarily stored in the head tank 39, and the liquid level control valve 57 can be opened and closed. For example, it can be performed by an output signal of the liquid level height measured by a liquid level gauge (not shown) installed in the head tank 39.

The size of the first supply pipe 41 according to the second embodiment is 50 A, but the size of the first supply pipe 41 may be appropriately selected according to the size of the shroud 37 and the heat load.

≪Second supply piping≫
As shown in FIGS. 3 and 4, the second supply pipe 43 connects the head tank 39 and the shroud 37, and supplies the liquid nitrogen temporarily stored in the head tank 39 to the shroud 37, and supplies the second supply pipe 43. It consists of pipes 43a and 43b. One end side (second supply pipe 43a) is connected to the lowermost part of the head tank 39, and the other end side (second supply pipe 43b) is connected to the lower part of the shroud 37.

As shown in FIG. 4, the second supply pipe 43 is provided with a liquid nitrogen circulation valve 59 and a valve box 61. The liquid nitrogen circulation valve 59 controls the supply and stop of liquid nitrogen from the head tank 39 to the shroud 37, and the valve box 61 is a flow control valve (not shown) that controls the supply flow rate of liquid nitrogen inside the valve box 61. ) Is installed. When a plurality of shrouds are installed in the vacuum vessel 33, a plurality of flow rate control valves connected to each shroud are installed in the valve box 61.

The size of the second supply pipe 43 according to the second embodiment is 50A as in the case of the above-mentioned second supply pipe 43, but the size of the second supply pipe 43 is the size of the shroud 37 and the heat load. It may be appropriately selected according to the above.

≪Discharge piping≫
The discharge pipe 45 is provided to connect the shroud 37 and the head tank 39 and discharge the mixed fluid of liquid nitrogen and gaseous nitrogen after cooling the shroud 37 to the head tank 39. Since the shroud 37 and the head tank 39 are connected by the discharge pipe 45, the shroud 37 and the head tank 39 are communicated with each other in an airtight manner.

≪Recovery piping≫
The recovery pipe 47 is for connecting the second supply pipe 43 and the first supply pipe 41, and recovering the liquid nitrogen in the head tank 39 and the shroud 37 to the liquid nitrogen storage tank 35.

≪Opening valve≫
The on-off valve 49 is provided in the recovery pipe 47, and when liquid nitrogen is supplied to the shroud 37 to cool it, the on-off valve 49 is in a closed state (see FIG. 4), and the head tank 39 and the shroud 37 are in a closed state. When the liquid nitrogen inside is recovered, the on-off valve 49 is opened (see FIG. 3).

≪Gaseous nitrogen supply part≫
The gaseous nitrogen supply unit 51 is provided in the head tank 39 and supplies pressurized nitrogen into the head tank 39. As shown in FIGS. 3 and 4, the gaseous nitrogen supply pipe 51a and the gaseous nitrogen are supplied. A gas supply valve 51b can be used.

The gas nitrogen supply unit 51 can connect a nitrogen cylinder (not shown) or the like to the gas nitrogen supply pipe 51a, and when pressurizing the inside of the head tank 39, the gas nitrogen release valve 55 is closed and the gas is gas. The nitrogen supply valve 51b is opened, and the gaseous nitrogen pressurized from the nitrogen cylinder is supplied to the head tank 39 through the gaseous nitrogen supply pipe 51a. It is desirable that the gas nitrogen supply valve 51b can control the opening degree so that the pressure inside the head tank 39 becomes constant.

The gaseous nitrogen supply unit 51 may have the gaseous nitrogen supply pipe 51a connected to the gaseous nitrogen release pipe 53, and the gaseous nitrogen pressurized to the head tank 39 with the gaseous nitrogen release valve 55 closed. Any gas may be used as long as it can be supplied to pressurize the inside of the head tank 39.

<Liquid nitrogen recovery method>
Next, the liquid nitrogen recovery method in the space environment test device 31 according to the second embodiment will be described together with the operation of the space environment test device 31 shown in FIGS. 3 and 4.

First, the liquid nitrogen circulation valve 59 is opened, and liquid nitrogen is supplied from the liquid nitrogen storage tank 35 to the shroud 37 via the first supply pipe 41, the head tank 39, and the second supply pipe 43 at a predetermined supply pressure. The shroud 37 is cooled and tested (see FIG. 4).

During the cooling operation, the on-off valve 49 provided in the recovery pipe 47 and the gaseous nitrogen supply valve 51b of the gaseous nitrogen supply section 51 are closed, and the mixed fluid of liquid nitrogen and gaseous nitrogen after cooling the shroud 37 is It is discharged from the discharge pipe 45 to the head tank 39. Then, the discharged liquid nitrogen is stored in the head tank 39, while the discharged gaseous nitrogen is released to the atmosphere through the gaseous nitrogen discharge pipe 53 and the gaseous nitrogen release valve 55.

When the test is completed and the cooling operation of the shroud 37 is completed, the liquid nitrogen storage tank 35 stops the supply of liquid nitrogen to the head tank 39 with the liquid level control valve 57 closed, and then the on-off valve 49 is opened to open the gas nitrogen. The release valve 55 is closed (see FIG. 3). Next, the gaseous nitrogen cylinder is connected to the gaseous nitrogen supply pipe 51a, the gaseous nitrogen supply valve 51b is opened, and the gaseous nitrogen pressurized from the gaseous nitrogen supply section 51 is supplied to the head tank 39.

In this way, by supplying gaseous nitrogen to the head tank 39 and applying pressure, a reverse pressure is applied to the liquid nitrogen stored in the head tank 39, and through the second supply pipe 43a, the recovery pipe 47, and the on-off valve 49. Along with being pressure-fed to the first supply pipe 41a, a reverse pressure is also applied to the liquid nitrogen stored in the shroud 37 communicating with the head tank 39 via the discharge pipe 45, and the second supply pipe is supplied. It is pressure-fed to the first supply pipe 41a side through 43b and the recovery pipe 47. Then, the liquid nitrogen pumped to the first supply pipe 41a is recovered in the liquid nitrogen storage tank 35 through the first supply pipe 41a.

The supply pressure of the gaseous nitrogen supplied to the gaseous nitrogen supply unit 51 may be set higher than the supply pressure of the liquid nitrogen supplied from the liquid nitrogen storage tank 35 during the cooling operation, and the liquid nitrogen is supplied from the liquid nitrogen storage tank 35. When the pressure is 0.3 MPaG, the supply pressure of the gaseous nitrogen supplied to the gaseous nitrogen supply unit 51 may be about 0.4 to 0.6 MPaG.

As described above, according to the liquid nitrogen recovery method of the space environment test device 31 and the space environment test device 31 according to the second embodiment, even in the space environment test device 31 that cools by the free boiling method, additional equipment such as a pump is provided. By supplying pressurized gaseous nitrogen to the head tank 39 without using it, the liquid nitrogen of the head tank 39 and the shroud 37 is pumped to the first supply pipe 41a side, and the pumped liquid nitrogen is pumped to the liquid nitrogen storage tank 35. Can be collected in. Further, since the inside of the second supply pipe 43 and the first supply pipe 41 used for cooling the shroud 37 are pumped, the influence of heat entering from the outside in the process of recovering liquid nitrogen is small and vaporization occurs. It is possible to reduce the amount of liquid nitrogen generated.

As another aspect of the liquid nitrogen recovery method of the space environment test device 31 and the space environment test device 31 according to the second embodiment, there is a gas nitrogen supply unit 51 that supplies pressurized nitrogen to the head tank 39. Instead, a heating means (not shown) for heating and vaporizing the liquid nitrogen in the head tank 39 may be provided.

In this case, the head tank 39 can be pressurized by heating and vaporizing at least a part of the liquid nitrogen in the head tank 39, thereby reversing the liquid nitrogen in the head tank 39 and the shroud 37. Pressure can be applied and pumped to the first supply pipe 41a side through the second supply pipe 43 and the recovery pipe 47.
As the heating means, a heater can be used as in the first embodiment described above, and the inside of the head tank 39 can be pressurized to a predetermined pressure by adjusting the output of the heater.

Further, in the space environment test apparatus 31 according to the second embodiment, it is difficult to directly grasp in which part of the pipes the liquid nitrogen is present when recovering the liquid nitrogen. Therefore, a thermometer 63 is provided in the first supply pipe 41 to measure the temperature of the liquid nitrogen to be pumped, and when the measured temperature tends to rise, the liquid is supplied to the shroud 37, the head tank 39, and the second supply pipe 43. It is possible to presume that nitrogen is absent and stop the recovery of liquid nitrogen.

That is, when the pumped liquid nitrogen flows through the first supply pipe 41, the temperature measured by the thermometer 63 is about the same as that of the pumped liquid nitrogen, whereas the head tank 39 and the shroud 37 When the liquid nitrogen of the above is recovered and the gaseous nitrogen supplied from the gaseous nitrogen supply section 51 flows into the first supply pipe 41, the temperature becomes about the same as that of the gaseous nitrogen measured by the thermometer 63, and the recovered liquid. This is because it is higher than the temperature of nitrogen.

Here, as shown in FIGS. 3 and 4, the thermometer 63 is closer to the liquid nitrogen storage tank 35 than the position where the second supply pipe 43a connected to the head tank 39 and the second supply pipe 43b connected to the shroud 37 are connected. It is preferable to install it in the first supply pipe 41a, and it may be installed in the recovery pipe 47.

Further, in the space environment test apparatus 31 according to the second embodiment, it is desirable to install the recovery pipe 47 so as to connect the lowermost part of the second supply pipe 43 and the lowermost part of the first supply pipe 41. As a result, when the inside of the head tank 39 is pressurized and the liquid nitrogen is pumped, the liquid nitrogen is transferred to the first supply pipe 41 side through the lowermost part in the vertical direction in the space environment test apparatus 31, so that the liquid nitrogen is transferred. It can be recovered in the liquid nitrogen storage tank 35 without leaving it in the pipes.

1 Space environment test equipment 3 Vacuum container 5 Liquid nitrogen supply equipment 7 Shroud 9 Discharge reservoir 11 Supply pipe 13 Discharge pipe 15 Recovery pipe 17 On-off valve 19 Gas nitrogen supply unit 19a Gas nitrogen supply pipe 19b Gas nitrogen supply valve 21 Gas nitrogen release Piping 23 Gas nitrogen release valve 25 Thermometer 31 Space environment test equipment 33 Vacuum vessel 35 Liquid nitrogen storage tank 37 Shroud 39 Head tank 41, 41a, 41b 1st supply pipe 43, 43a, 43b 2nd supply pipe 45 Discharge pipe 47 Recovery pipe 49 On-off valve 51 Gas nitrogen supply section 51a Gas nitrogen supply pipe 51b Gas nitrogen supply valve 53 Gas nitrogen release pipe 55 Gas nitrogen release valve 57 Liquid level control valve 59 Liquid nitrogen circulation valve 61 Valve box 63 Thermometer 71 Space environment test equipment ( Conventional example)
73 Pump 75 Recovery piping 81 Space environment test equipment (conventional example)
LN ₂ liquid nitrogen
GN ₂ gaseous nitrogen

Claims (6)

A shroud provided in a vacuum vessel and cooled by receiving the supply of liquid nitrogen from the liquid nitrogen supply device and the liquid nitrogen supplied from the liquid nitrogen supply device are temporarily stored, and the temporarily stored liquid nitrogen is stored in the shroud. A head tank for storing liquid nitrogen discharged from the shroud is provided, and the shroud is cooled by a free boiling method to test the inside of the vacuum vessel in a state simulating the cold and dark of the space environment. It is a space environment test device that performs
A first supply pipe that connects the liquid nitrogen supply device and the head tank and supplies liquid nitrogen from the liquid nitrogen supply device to the head tank.
A second supply pipe that connects the head tank and the shroud and supplies liquid nitrogen temporarily stored in the head tank to the shroud.
A discharge pipe that connects the shroud and the head tank and discharges liquid nitrogen that has cooled the shroud to the head tank.
A recovery pipe that connects the second supply pipe and the first supply pipe and collects the liquid nitrogen in the head tank and the shroud to the liquid nitrogen supply device.
An on-off valve provided in the recovery pipe and
It has a gaseous nitrogen supply unit that supplies pressurized gaseous nitrogen in the head tank, and has.
With the on-off valve open, pressurized nitrogen is supplied to the gaseous nitrogen supply unit, and liquid nitrogen in the head tank and in the shroud communicating with the head tank is supplied to the second supply pipe and the second supply pipe and the said. A space environment test apparatus characterized in that it is pumped to the first supply pipe side via a recovery pipe, and the pumped liquid nitrogen is recovered by the liquid nitrogen supply device. A shroud provided in a vacuum vessel and cooled by receiving the supply of liquid nitrogen from the liquid nitrogen supply device and the liquid nitrogen supplied from the liquid nitrogen supply device are temporarily stored, and the temporarily stored liquid nitrogen is stored in the shroud. A head tank for storing liquid nitrogen discharged from the shroud is provided, and the shroud is cooled by a free boiling method so that the inside of the vacuum vessel is in a state of simulating the cold and dark of the space environment. A space environment test device that conducts tests
A first supply pipe that connects the liquid nitrogen supply device and the head tank and supplies liquid nitrogen from the liquid nitrogen supply device to the head tank.
A second supply pipe that connects the head tank and the shroud and supplies liquid nitrogen temporarily stored in the head tank to the shroud.
A discharge pipe that connects the shroud and the head tank and discharges liquid nitrogen that has cooled the shroud to the head tank.
A recovery pipe that connects the second supply pipe and the first supply pipe and recovers the liquid nitrogen in the head tank and the shroud to the liquid nitrogen supply device.
An on-off valve provided in the recovery pipe and
It has a heating means for heating and vaporizing the liquid nitrogen in the head tank.
With the on-off valve open, the liquid nitrogen in the head tank is heated and vaporized by the heating means to pressurize the inside of the head tank, and the inside of the head tank and the inside of the shroud communicating with the head tank. Liquid nitrogen was pumped to the first supply pipe side via the second supply pipe and the recovery pipe, and the pumped liquid nitrogen was recovered in the liquid nitrogen supply device. apparatus. The space environment test apparatus according to claim 1 or 2, wherein a thermometer is installed in the first supply pipe or the recovery pipe. The space environment test apparatus according to any one of claims 1 to 3, wherein the recovery pipe connects the lowermost portion of the second supply pipe and the lowermost portion of the first supply pipe. A shroud provided in a vacuum vessel and cooled by receiving the supply of liquid nitrogen from the liquid nitrogen supply device and the liquid nitrogen supplied from the liquid nitrogen supply device via the first supply pipe are temporarily stored and temporarily stored. The vacuum is provided by supplying the stored liquid nitrogen to the shroud via a second supply pipe and providing a head tank for storing the liquid nitrogen discharged from the shroud, and cooling the shroud in a free boiling manner. This is a method for recovering liquid nitrogen in a space environment test device that recovers liquid nitrogen in a space environment test device that conducts tests by simulating the cold and darkness of the space environment inside the container.
By connecting the second supply pipe and the first supply pipe via a recovery pipe and supplying pressurized nitrogen to the head tank to pressurize the inside of the head tank, the inside of the head tank and the inside of the head tank are pressed. Liquid nitrogen in the shroud communicating with the head tank is pumped to the first supply pipe side via the second supply pipe and the recovery pipe, and the pumped liquid nitrogen is recovered to the liquid nitrogen supply device. A method for recovering liquid nitrogen from a space environment test device. A shroud provided in a vacuum vessel and cooled by receiving the supply of liquid nitrogen from the liquid nitrogen supply device and the liquid nitrogen supplied from the liquid nitrogen supply device via the first supply pipe are temporarily stored and temporarily stored. The vacuum is provided by supplying the stored liquid nitrogen to the shroud via a second supply pipe and providing a head tank for storing the liquid nitrogen discharged from the shroud, and cooling the shroud in a free boiling manner. This is a method for recovering liquid nitrogen in a space environment test device that recovers liquid nitrogen in a space environment test device that conducts tests by simulating the cold and darkness of the space environment inside the container.
The inside of the head tank and the inside of the head tank are formed by connecting the second supply pipe and the first supply pipe via a recovery pipe and pressurizing the inside of the head tank by heating and vaporizing the liquid nitrogen in the head tank. Liquid nitrogen in the shroud communicating with the head tank is pumped to the first supply pipe side via the second supply pipe and the recovery pipe, and the pumped liquid nitrogen is recovered to the liquid nitrogen supply device. A method for recovering liquid nitrogen in a space environment test device.

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