JP4151907B2 - Slide valve - Google Patents

Description

The present invention relates to a slide valve .

In the drive of a slide type pressure valve, pressure is applied to one side when the slide valve is closed, and a large force is required to move the slide valve due to friction.

The problem to be solved by the present invention is to reduce the frictional force even during the opening and closing of the slide valve to make the slide valve move smoothly.

In order to solve the above problems, the present invention is configured as follows. For a slide valve having a sliding opening / closing structure in which pressure is applied in the cross direction of the slide direction, a pressure input passage that branches from one surface side of the slide valve and faces the one surface, and another surface of the slide valve A pipe that becomes a pressure input passage that faces the surface, a pressure output passage that branches from the other surface side of the slide valve and faces the other surface, and faces the one surface of the slide valve And a pipe serving as a pressure output passage for balancing the pressure applied to one surface of the slide valve with the pressure applied to the other surface.
Such a slide valve has a sealed tank having a water supply valve and a drainage valve, and a tank internal / external communication path that serves as an air passage that allows communication between the inside and outside of the sealed tank, and a pressure that causes a pressure difference between the inside and outside of the sealed tank by water supply / drainage to the sealed tank. It is a difference generator that can naturally supply water from the high water level water source outside the sealed tank into the sealed tank by opening the water supply valve.When water is supplied from this high water level water source, the inside of the sealed tank is pressurized and the drain valve is opened. nature drainable a water accumulated into the sealed tank to a low level water source outside the closed tank with a plug, can be applied to the pressure difference-generating apparatus in the closed tank when the drainage to the low water level the water source is reduced.

  Here, the said closed tank consists of two closed tanks, a 1st closed tank and a 2nd closed tank, and the tank internal / external communication path shall be what connected the 1st closed tank and the 2nd closed tank. .

  Moreover, the said closed tank shall consist of two closed tanks, a 1st closed tank and a 2nd closed tank, and shall have an underwater communication path which connects the bottoms of a 1st closed tank and a 2nd closed tank. it can.

  Further, the closed tank may be a multistage combination of two closed tanks, a first closed tank and a second closed tank.

  In addition, this pressure difference generator can be a power generator that generates power by providing an air turbine in the tank internal / external communication path and rotating the air turbine with the airflow generated in the tank internal / external communication path.

  Furthermore, this pressure difference generating device can be an airflow generating device in which an air valve is provided in the tank internal / external communication path, and air is supplied / exhausted to / from the sealed tank by opening / closing the air valve.

  Furthermore, this pressure difference generating device is provided with a piston cylinder structure driving device in which the piston portion is driven by the pressure in the cylinder portion at the end of the tank internal / external communication path, and the inside / outside of the sealed tank transmitted through the tank internal / external communication path is provided. The piston portion can be driven with a pressure difference of.

  Such a pressure difference generator can be provided with a water surface maintenance tank in which a pipe volume increasing portion is provided in a pipe communicating the driving device and the sealed tank, and the vertical movement of the water level in the pipe can be suppressed. .

  In addition, a position detection sensor that contacts the piston portion of the drive device is provided, and a bypass hole that penetrates from one end of the piston portion to the other end is provided in the piston portion, and the end of the position detection sensor is bypassed by movement of the piston portion. A position detection device that detects the movement position of the piston part by matching the hole and communicating with the outside of the piston part through the bypass hole can be provided.

  Furthermore, a bypass port is provided in the piston portion of the drive device, and the bypass port moves in conjunction with the movement of the piston portion, and the bypass port communicates the inside and outside of the cylinder portion at a position where the piston portion is stationary. A stationary device that eliminates the pressure difference between the inside and outside of the cylinder portion and stops the movement of the piston portion can be provided.

  Furthermore, a pressure sealing structure may be provided in the drive device, and an impact absorbing device that stops the movement of the piston portion may be provided.

  Further, a sluice that secures the high water level water source and the low water level water source from the tide level difference is further provided, and the sluice gate includes a sluice closing part that partitions a boundary between the high water level side water source and the low water level side water source, and a sluice water closing part. A sluice rotary part serving as a rotation center, and a weight balance part for providing a weight balance with respect to the sluice closed part around the sluice rotary part. The boundary with the reduced water level side water source can be automatically opened and closed.

  A cylinder part is provided in the movable region of the weight balance part of the sluice, and a pressure control and a pressure release part are communicated with the cylinder part to enable control of the sluice by pressure.

  In addition, a sluice that secures high and low water sources from the tide level difference is further provided, and this sluice is connected to the sluice flat water section that separates the boundary between the high water level water source and the low water level water source, and It has a sluice rotary part serving as a moving center, and its specific gravity approximates that of water, so that it can move in the water flow and can be closed by its own weight of the sluice closing part and the sluice rotary part.

Or configured as follows. That is, a closed tank having a water supply valve and a drain valve, a tank internal / external communication path that serves as an air passage that allows communication between the inside and outside of the closed tank, a high water level water source, and a low water level water source are used to supply and discharge the sealed tank. A pressure difference generation method that creates a pressure difference. Open the drain valve in contact with the low water level water source, close the water supply valve in contact with the high water level water source, and drain naturally outside the sealed tank. A pressure difference generating method that repeatedly executes a step of reducing pressure and a step of closing the drain valve, opening the water supply valve, and pressurizing the inside of the sealed tank by naturally supplying water into the sealed tank. .

  Alternatively, in this pressure difference generation method, the closed tank is provided with two closed tanks of the first closed tank and the second closed tank, and the first closed tank and the second closed tank are communicated with each other through the tank internal / external communication path. Open the drain valve in contact with the low water level water source of the first sealed tank, close the water supply valve in contact with the high water level water source, and drain the natural water outside the first sealed tank, and the low water level water source of the second sealed tank The drain valve in contact with the water, and the water supply valve in contact with the high water level water source is opened to naturally supply water into the second sealed tank, and the second sealed tank is set to a pressure higher than that of the first sealed tank; The drain valve is closed and the water supply valve is opened to naturally supply water into the first sealed tank, and the drain valve of the second sealed tank is opened and the water supply valve is closed to close the outside of the second sealed tank. Drains naturally to the 1st airtight tank and 2nd airtight It can be made to run by repeating the steps, to high pressure from the tank.

  Furthermore, two closed tanks having a water supply valve and a drain valve, a tank internal / external communication path serving as an air passage that allows communication between the inside and outside of the closed tank, and water that communicates between the bottoms of the first closed tank and the second closed tank. A pressure difference generating method for generating a pressure difference between the inside and outside of the sealed tank by supplying and discharging water to and from the sealed tank from inside the closed tank, wherein the water supply valve, the drain valve, and the underwater connecting path are closed, The underwater communication path can be opened from a state where there is a difference in water level between the sealed tank and the second sealed tank.

  With regard to this water source, a multi-stage maximum water level water source is secured as a high water level water source at high tide during the high tide period, a multi-stage minimum water level water source is secured as a low water level water source at low tide during the high tide period, and a multi-stage type is used as a high water level water source during periods other than the high tide period. Each step of securing a high water level water source or securing a multi-stage low water level water source as a low water level water source other than during the tidal period can be provided.

According to the slide valve of the present invention, it is possible to reduce the frictional force even during opening and closing and to make the movement smooth.

A power generation device using hydropower will be described. As shown in Fig. 1 and Fig. 2, the power generation tank (1), the water supply valve (3), and the drainage valve are located in the two water sources that have a difference in water level between the high water level water source (5) and the low water level water source (6). (4) Install the power generation turbine (2). When the power generation turbine (2) is placed above the water level of the high water level water source (5) above the power generation tank (1), the power generation turbine (2) ) Can enter and exit air.
As shown in FIG. 1, when the water supply valve (3) is closed and the drainage valve (4) is opened to drain water from the power generation tank (1), the pressure in the power generation tank (1) decreases and the intake turbine becomes intake air (2 ) Rotates. In addition, as shown in FIG. 2, when the drain valve (4) is closed and the water supply valve (3) is opened, water supply begins to the power generation tank (1), and the pressure in the power generation tank (1) rises and exhausts. The power generation turbine (2) rotates. This power generation apparatus repeats this process, and rotates the generator with the rotational force of the power generation turbine (2).

Next, the power generator shown in FIG. 3 will be described. The water intake valve (3) is closed and the drain valve (4) is open.The intake port (8a) of the power generation tank (8) is fully decompressed and the drain valve (4) is closed and the water supply valve (3) is closed. When the turbine for power generation (2) is connected between the exhaust port (9a) of the power generation tank (9) that is pressurized with open water reduction, the pressure generated in each power generation tank (8, 9) is added. In addition, it is possible to generate power at a pressure twice that of a single power generation tank. That is, high-efficiency power generation can be performed at high speed and pressure.
Then, when the water supply / drainage is switched next, the decompression of the power generation tank (8) and the pressurization of the power generation tank (9) are interchanged, and the same highly efficient power generation can be performed in the opposite direction. In particular, it is an effective means for power generation in an environment where the pressure is insufficient due to a low water level difference.

FIG. 4 shows a sluice (57) that can be used to secure a water source such as a high water level water source (5) and a low water level water source (6) by using the tide level difference (tide level fluctuation). As shown in FIG. 5, the sluice (57) shown in FIG. 4 has the sluice closing part (29) balanced by the sluice weight balance part (31) by the sluice rotary part (30) according to the seesaw principle. Open and close according to the water level difference. The operation principle of the sluice (57) will be described with reference to FIGS.
As shown in FIGS. 6 and 7, the sluice closing part (29) of the sluice (57) reacts to water pressure and water flow. For example, when the water level on the side to be blocked rises, as shown in FIG. 7, the sluice closing part (29) is covered and blocked by the water flow from the increased water source (34), and further sealed with water pressure. You can raise the degree. Thus, the sluice closing part (29) reacts to water pressure and water flow.
Basically, it can be operated regardless of whether the rotation axis of the sluice rotary part (30) is horizontal or vertical, but when the water level falls below the sluice (57), it becomes difficult to operate due to friction caused by the weight of the sluice (57). Therefore, it is preferable that the rotation axis is horizontal because it is easier to create an environment in which the rotation axis is disposed in water.

Such a sluice (57) is preferably provided with an impact absorbing part (32) and a pressure sealing bit (37) when the sluice is closed as shown in FIGS. 4 and 8, and at the moment when the sluice close part (29) is covered. The structure formed by the shock absorbing part (32) and the pressure sealing bit (37) can seal water and reduce the speed at the moment when the lid is closed.
Further, when a piston cylinder structure is formed by the sluice weight balance portion (31) and the cylinder portion (14) shown in FIG. 5, the pressure control and the pressure release portion are connected to the piston cylinder structure, the pressure control can open and close. If a valve for releasing pressure is attached to the cylinder part (14), both pressure control and natural opening / closing functions can be exhibited.

  If the operating environment of this sluice (on / off valve) is underwater, even if there is no sluice weight balance part (31) like the sluice (58) shown in FIG. Because it exists like a drift, it will react to the water flow without friction due to its own weight. If the specific gravity of the sluice closing part (29) and the sluice rotation part (30) is slightly heavier than water, the weight of the sluice closing part (29) and the sluice rotation part (30) will be reduced without water pressure difference or water flow. Can be naturally covered.

  When power is generated using the tide level difference, as shown in Fig. 10, by opening and closing the sluice gates (57,58), a multi-stage maximum water level water source (38) is secured at high tide during the high tide, and the multi-stage minimum at low tide. Secure the water source (41) and close the sluice (57,58). Even when it is not during the high tide, a multi-stage high water level water source (39) and a multi-stage low water level water source (40) are secured according to the level of the tide level. Then, only the water supply for obtaining the highest water level (42) in the tank of the multistage water source power generation tank (53) is performed by the multistage highest water level (38), and only the drainage for obtaining the lowest water level in the tank (45) is multistage. Make adjustments based on the water source as in the lowest water level (41). This type of handling is effective in an environment where it is difficult to secure a water source with a high water level difference, regardless of tidal difference power generation.

  In addition, as shown in FIG. 11, tide level difference power generation does not use many devices as described above, but places a power generation tank in the sea to open the underwater part and generates power only by raising and lowering the tide level. can do. Power generation efficiency is poor and large power can be obtained only during the tidal period, but it is practical as an additional function for coastal facilities.

The power generation tank (1) can be a control pressurized tank (10) as a power source. That is, a drive device that applies the pressure generated in the tank to the control based on the same principle as the power generation tank (1) can be provided. As shown in FIG. 12, the control pressurized tank (10) is provided with an air valve (16) at the top thereof. Drain from the control pressure tank (10) and close the air valve (16) and drain valve (4). Next, when the water supply valve (3) of the high water level water source (5) is opened, the water level (12) in the tank in the control pressurized tank (10) rises, so that the air valve (16) is pressurized. This state can be maintained and used as a pressure supply source when needed for control.
A drive pipe (13) is piped at the tip of the air valve (16) and connected to the cylinder part (14) of the drive device of the piston cylinder structure. The water surface maintenance tank (17) is attached to the water surface position of the drive pipe (13). The cylinder part (14) connected to the pressurized air valve (16) is able to move the piston part (14a) due to the increased internal pressure.

  As shown in FIG. 13, when water is supplied into the control decompression tank (11), the air valve (16) and the water supply valve (3) are closed, and the drain valve (4) of the low water level water source (6) is opened. Since the water level in the pressure reducing tank (11) is lowered, the pressure is reduced by the air valve (16). This state can be maintained and used as a reduced pressure supply source when needed for control. In this case, the atmospheric pressure is used as a reference, and the pressure becomes negative by the amount of water of the water level difference. The drive pipe (13) is connected to the control decompression tank (11), and can pull the water surface of the water surface maintenance tank (17) to move the underwater drive device. If there is no water level maintenance tank (17), the water level rises due to the reduced pressure, so the pressure decreases due to the difference in water level. The same applies to the pressurization control. Drive control can be performed underwater using such a pressure source.

FIG. 14 shows that the water in the pressure-increasing control decompression tank (18) is connected to the water in the pressure-increasing control pressure tank (19), and the exhaust port (10a) of the control pressure tank (10) is connected. The drive device is connected to the intake port (18a) of the pressure-reducing pressure-reducing tank (18). The exhaust port (19a) of the pressure increase control pressure tank (19) is connected to a pressure gauge.
With the water supply valve (3), drain valve (4), and air valve (16) of the control pressure tank (10) closed, the pressure increase control pressure reduction tank (18) and the pressure increase control pressure tank By connecting (19) in this way, it is insulated from the atmospheric pressure and pressurized only with the potential energy of the water level difference in the tank connected in water, so the exhaust port (19a) of the pressure increase control pressure tank (19) ) Can extract a greater pressure. This is because the control pressurized tank (10) is pushed by the atmospheric pressure of the high water level water source (5), but the pressure-increasing control decompression tank (18) and the pressure-increasing control pressure tank (19) Because it is insulated.
The position where the water surfaces of the pressure-increasing control decompression tank (18) and the pressure-increasing control pressure tank (19) are aligned is the water level (20) when the pressure-intensifying completion is completed. That is, for the three tanks to be simultaneously pressurized and depressurized, the capacity of the pressure-increasing control decompression tank (18) and the pressure-increasing control pressure tank (19) is double the capacity of the control pressure tank (10). I need it.
In this drive device, the pressure-increasing control decompression tank (18) and the pressure-increasing control pressure tank (19) can be connected in multiple stages to further increase the pressure.

Next, detection of the movement position of the piston part (14a) will be described.
FIG. 15 shows a slide position detecting device for the piston portion (14a). The piston part (14a) is provided with a bypass hole (24) for detecting the movement position. A pressure detection port (25) is provided at the tip of the drive tube (13) connected to the sensor (13a). When the piston part (14a) moves and the movement position detection bypass hole (24) reaches the pressure detection port (25) as shown in FIG. 16, the movement position of the piston part (14a) is detected. .
In detecting the moving position of the piston portion (14a), the pressure of the drive pipe (13) directly connected to the sensor (13a) is set not to be the pressure of the water depth. Then, when the bypass hole (24) for moving position detection reaches the pressure detection port (25) and they overlap, the change in pressure is detected by the sensor (13a) at the upper port of the drive tube (13). Can do.

A stationary device that stops the movement of the piston portion (14a) will be described.
This device is a device that prevents the runaway due to movement of the piston portion (14a) in water.
As shown in FIG. 17, the piston portion (14a) is provided with a stationary pressure bypass port (26) for releasing the pressure in the cylinder portion (14) at a predetermined position of the piston portion (14a). ing. When the piston part (14a) moves to the predetermined position, the pressure in the cylinder part (14) is released to the outside, so that the piston part (14a) is stopped.
This method can be used for driving at the time of pressurization, and this function is effective as a malfunction protection function of the driving device.

An impact absorbing device for the piston portion (14a) when the piston portion (14a) is driven will be described.
As shown in FIG. 18, the end of the cylinder part (14) has a pressure sealing structure. For this reason, even if there is an inertial force in the piston part (14a) by the decompression drive, the piston part (14a) does not collide with the cylinder part (14).
Because it is very difficult to maintain underwater, such a structure with many functions is important. It also has the advantage of being able to use materials that are durable in water, such as concrete.

Next, the underwater valve will be described.
When the slide type pressure valve (15) (hereinafter also referred to as “slide valve”) is driven, as shown in FIG. 19, when the slide valve (15) is closed, pressure is applied to one side, and the slide is caused by friction. A large force is required to move the valve (15). Therefore, as shown in FIG. 20, a pressure passage 1 (54), a pressure passage 2 (55), and a pressure passage 3 (56), which are pressure inlet / outlet passages, are provided. Here, the pressure passage 2 (55) and the pressure passage 3 (56) are provided so as to cancel the pressure vector applied to the plate surface of the slide valve (15) relative to the pressure passage 1 (54). Such a pressure inlet / outlet passage includes a pressure passage 2 (55) and a pressure passage 3 (56), and a pressure passage 1 (54) in the opposite direction to the pressure passage 1 (54) in both directions perpendicular to the sliding direction of the slide valve (15). It can be evenly arranged with a cross-sectional area of 2.
That is, as shown in FIG. 21 and FIG. 22, the piping of the pressure input passage (22) and the pressure output passage (23), which are the pressure passages 1 to 3 (54, 55, 56) on both surfaces of the slide valve (15). Provide piping. Since both the pressure input passage (22) and the pressure output passage (23) exist on one side of the slide valve (15), the piping of the pressure input passage (22) and the piping of the pressure output passage (23) 15) It will be shaped to surround both sides.

  If such a method is taken, as can be seen from FIG. 21 showing when the slide valve (15) is opened, and FIG. 22 showing when the slide valve (15) is closed, the vector of pressure can be obtained even during the opening and closing of the slide valve (15). Balanced, the frictional force can be reduced and the slide valve (15) can move smoothly.

For the underwater valve, a fan column pressure valve (27) as shown in FIGS. 23 and 24 can be used. The fan column pressure valve (27) is a bottom fan-shaped columnar body as shown in FIG. It is installed as shown in FIG. 24, receives the pressure by the opening / closing part (27a) of the fan-shaped arc surface, blocks the water flow, and supports the pressure by the support part (28). The portion where the fan column pressure valve (27) shown in FIG. 24 is buried serves as a piston cylinder structure and plays the role of a piston cylinder.
Piping from the drive pipe (13) to the opening / closing part (27a), the fan column pressure valve (27) can be moved up and down by pressure. The advantage of the fan column pressure valve (27) is that pressure is received by the fan section outside the rotation and the pressure is supported by the support section (28) which is the rotating shaft, and the rotating shaft is rubbed. Therefore, pressure control works advantageously against friction that prevents driving from the law of moments.

  The fan column pressure valve (27) can assist opening and closing of the large flow rate slide valve (52) having a high degree of sealing. As with the slide valve (15) shown in FIG. 19, the large flow rate slide valve (52) closed with pressure is difficult to open and close due to friction. However, as shown in FIG. 25, the fan column pressure valve (27) is disposed so as to close the space on the low pressure side of the large flow type slide valve (52), and a closed chamber is once created by the fan column pressure valve (27). . Then, the pressure passage 1 (54) to the pressure passage 3 (56) are piped, and pressure is injected into the closed chamber to eliminate friction caused by the pressure of the large flow type slide valve (52). Thus, the large flow rate slide valve (52) can be easily opened and closed. The performance of the valve is important in an apparatus with a large number of times of opening and closing the valve, but with this method, the burden on the valve is small and the life of the apparatus can be extended. This device can serve as the main function of a large capacity on-off valve even if the degree of sealing of the fan column pressure valve (27) is not very good.

  In order to link the above contents, it is natural that human control is impossible, and electronic control that comprehensively manages water supply valves, drainage valves, supply / exhaust valves, turbines, and other drive control and sensor information. Equipment is required.

The schematic diagram of the apparatus for electric power generation at the time of drainage. The schematic diagram of the apparatus for electric power generation at the time of water supply. The schematic diagram of the apparatus for electric power generation which made the tank for electric power generation 2 stations. The perspective view of a sluice. The operation explanatory view of a sluice. Opening operation explanatory drawing of a sluice. The closing operation explanatory drawing of a sluice. Explanatory drawing of shock absorption operation at the time of sluice gate closing. The perspective view of the sluice without a weight balance part. The schematic diagram of the electric power generating apparatus by a tide level difference. The schematic diagram of the electric power generating apparatus by another tide level difference. The schematic diagram of the drive device of a pressurization state. The schematic diagram of the drive device of a pressure reduction state. The schematic diagram of the drive device which made the tank for control triple. The schematic diagram of the movement position detection apparatus of the state which the pressure bypass hole for position detection closed. The schematic diagram of the movement position detection apparatus of the state which the pressure bypass hole for position detection opened. The schematic diagram of a stationary apparatus. The schematic diagram of an impact-absorbing device. The perspective view of the state which a slide valve does not open with pressure. The conceptual diagram of the water flow to a slide valve. Schematic diagram of pressure passage and water flow when slide valve is open. Schematic diagram of pressure passage and water flow when slide valve is closed. The perspective view of a fan column pressure valve. Operation | movement explanatory drawing of a fan pillar pressure valve. Operation | movement explanatory drawing of the fan pillar pressure valve which assists opening and closing of a slide valve.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Power generation tank 2 Power generation turbine 3 Water supply valve 4 Drain valve 5 High water level water source 6 Low water level water source 7 Water level in power generation tank 8 Power generation tank (decompressed when full)
8a Inlet 9 Power generation tank (Pressurized with reduced water)
9a Exhaust port 10 Pressurized tank for control 10a Exhaust port 11 Depressurized tank for control 12 Water level in tank 13 Drive pipe 13a Sensor 14 Cylinder part 14a Piston part 15 Slide valve 15a, 15b Contact surface 16 Air valve 17 Water surface maintenance tank 18 Increase pressure Pressure reducing tank for control 18a Inlet port 19 Pressurizing tank for increasing pressure control 19a Exhaust port 20 Water level at completion of pressure increase / decrease 21 Water control valve 22 between tanks Pressure input passage 23 Pressure output passage 24 Bypass hole (for position detection)
25 Pressure detection port 26 Pressure bypass port 27 Fan column pressure valve 27a Open / close unit 28 Support unit 29 Water gate closing unit 30 Water gate rotation unit 31 Water gate weight balance unit 32 Shock absorber 33 Pressure control and pressure release unit 34 Water supply level side water source 35 Low water level side water source 36 Water gate closing side parallel plate 37 Pressure filled bit 38 Multistage high water level water source 39 Multistage high water level water source 40 Multistage low water level water source 41 Multistage low water level water source 42 High water level in tank 43 High water level in tank Water level 44 Low water level in the tank 45 Low water level in the tank 46 Water supply valve for the highest water level 47 Water supply valve for the high water level 48 Water supply valve for the low water level 49 Water drainage valve for the lowest water level 50 Water level at high tide 51 Water level at low tide 52 Large flow type slide valve 53 Multistage water source power generation tank 54 Pressure passage 1
55 Pressure passage 2
56 Pressure passage 3
57, 58 Sluice

Claims (2)

In a slide valve with a sliding opening / closing structure where pressure is applied in the crossing direction of the sliding direction,
A pipe that branches from one surface side of the slide valve and faces the one surface, and a pressure input passage that faces the other surface of the slide valve;
A pipe that branches from the other surface of the slide valve and faces the other surface and a pressure output passage that faces the one surface of the slide valve;
And a pressure applied to one surface of the slide valve is balanced with a pressure applied to the other surface. This is a pressure difference generator that has a closed tank with a water supply valve and a drain valve, and a tank internal / external communication path that is an air passage that allows communication between the inside and outside of the closed tank, and creates a pressure difference between the inside and outside of the closed tank by supplying and discharging water to the closed tank. By opening the water supply valve, it is possible to naturally supply water from the high water level water source outside the sealed tank into the sealed tank.When water is supplied from this high water level water source, the inside of the sealed tank is pressurized, and the drain valve is opened to enter the sealed tank. 2. The slide valve according to claim 1, wherein the stored water can be naturally drained to a low water level water source outside the sealed tank, and is provided in a pressure difference generator that depressurizes the inside of the sealed tank when draining to the low water level water source.

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