JP2004293449A - Water filling device and pumping station using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water filling device which has fewer factors of failure and high certainty in the operation when needed as the water filling device using a dry type vacuum pump having high economical efficiency as a whole of the device. <P>SOLUTION: The water filling device is used for making negative pressure state to fill water into a pump casing 13 of the lifting pump when starting pumping water with the pump, and therefore, has the dry type vacuum pump 36 for making the negative pressure state. The water filling device is provided with a first water filling detection means 32 adjacent to the pump casing and a second water filling detection means 42 between the first water filling detection means and the vacuum pump. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００３１】
以下では、参考までに水封式真空ポンプと乾式２段ルーツ形真空ポンプの性能比較について説明する。図３は、同一の駆動電動機容量において水封式真空ポンプと乾式２段ルーツ形真空ポンプの性能を比較したグラフである。その横軸は負圧であり、縦軸は吸込風量である。この比較から判るように、同一の駆動電動機容量において、乾式２段ルーツ形真空ポンプＤは水封式真空ポンプＷの吸込風量をほぼカバーすることができ、水封式真空ポンプに代えて用いても十分な性能を持った満水装置を構成することが可能となる。
【００３２】
次に、本発明による満水装置を複数台の揚水ポンプが設けられている揚水ポンプ機場に適用する場合の実施形態について説明する。複数台の揚水ポンプに本発明による満水装置を適用する場合、揚水ポンプ１台毎に満水装置１台ずつ設ける方式と満水装置を部分的に共有させて複数台の揚水ポンプの満水操作を行なう方式が可能である。揚水ポンプ１台毎に満水装置１台ずつ設ける方式とする場合には、図１の構成を並列に並べることと同じである。この場合には複数台の揚水ポンプに対して同時に満水操作を行なうことができるという利点がある。一方、満水装置を部分的に共有させる方式では、複数台の揚水ポンプに対して順番に満水操作を行なうことになるものの、揚水ポンプ機場全体のコストを大幅に低減できるという利点がある。本発明による満水装置を部分共有方式とするについては、図１の満水装置の場合であれば、分離弁４１より下流側を共有とし、分離弁４１とそれより上流側を揚水ポンプ１台ごとに設ける形態とするのが好ましい。この形態における満水操作は、図２の運転制御処理にしたがって複数台の揚水ポンプに対して順に満水操作を施し、それを全部の揚水ポンプに完了した後に真空ポンプ３６の乾燥用運転を行なうことになる。なお揚水ポンプ停止後に行なわれる第１の真空ブレーク弁４０の開は、揚水ポンプごとに実施するようにしてもよく、また全揚水ポンプの停止を受けて全揚水ポンプに一斉に実施するようにしてもよい。
【００３３】
【発明の効果】
以上説明したように本発明では、揚水ポンプのポンプケーシングに近接して設けられる第１の満水検知手段に加えて、その下流側に第２の満水検知手段を設けるようにしている。このため、第１の満水検知手段に故障を生じて満水検知をなすことができなくても第２の満水検知手段でバックアップすることができ、真空ポンプが吸水する危険性を大幅に低減させることができる。したがって本発明によれば、乾式の真空ポンプが用いられた満水装置の必要時の作動確実性を大幅に高めることができ、ひいては揚水ポンプの必要時の作動確実性も大幅に高めることができる。
【図面の簡単な説明】
【図１】本発明一実施形態による満水装置とそれを適用した揚水ポンプの構成を模式化して示す図である。
【図２】図１の満水装置と揚水ポンプの運転制御における処理の流れを示すフローチャート図である。
【図３】水封式真空ポンプと乾式２段ルーツ形真空ポンプの性能比較についてのグラフを示す図である。
【符号の説明】
１３ ポンプケーシング
３２ 第１の満水検知手段
３３ 緩衝槽
３６ 真空ポンプ
４１ 分離弁
４２ 第２の満水検知手段[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a water filling device for a pump, and more particularly to a water filling device using a dry vacuum pump and a pumping station using the same.
[0002]
[Prior art]
The pump is used, for example, as a drain pump of a drainage facility for draining a large amount of rainfall or emergency flooding due to river flooding. Such pumps are generally in the form of horizontal shaft pumps. The horizontal shaft pump includes a pump casing in which a pump impeller is disposed. When starting pumping, it is necessary to fill the pump casing with water by an external force. For this purpose, the pump is equipped with a water filling device as an auxiliary device. That is, the water filling device for the water pump is an auxiliary device used to fill the pump casing of the water pump with a negative pressure state to fill the water at the start of water pumping by the water pump. Is equipped with a vacuum pump.
[0003]
In the conventional water filling device, a water ring type vacuum pump was used as the vacuum pump. The major reason is that even if water (which is often turbid water) is sucked in during a water filling operation, the performance of a water ring vacuum pump will not be reduced. However, water-sealed vacuum pumps require sealed water supply facilities such as water storage tanks and water supply pumps, which increase the size of the water filling device and make the vacuum pump itself relatively expensive, but the overall cost of the device is high. There is a disadvantage that. In addition, when the pump is used as a drainage pump, the frequency of operation is generally low because it is used for emergency water discharge countermeasures. It has been desired to further improve reliability, for example, the rotor of the vacuum pump is rusted and fixed by moisture.
[0004]
For these reasons, there is an increasing demand for dehydration of the water filling device, and recently, there is a tendency that a water filling device using a dry vacuum pump is adopted as the vacuum pump. However, dry vacuum pumps also have problems. That is, since a dry vacuum pump basically dislikes moisture, it is necessary to provide a sufficient mechanism for preventing water from being sucked into the vacuum pump. Patent Literature 1 and Patent Literature 2 disclose examples of pumps using a water filling device that meets such demands as an auxiliary device.
[0005]
In the water pump (horizontal axis pump) disclosed in Patent Document 1, a sufficient rising portion is provided in an intake pipe connecting the pump casing of the water pump and the vacuum pump of the water filling device, and the rising portion prevents water absorption of the vacuum pump. I have to. Therefore, a dry vacuum pump can be used as the vacuum pump. On the other hand, in the water pump (horizontal axis pump) disclosed in Patent Document 2, a vacuum tank is provided in the middle of a pipe connecting the pump casing of the water pump and the vacuum pump of the water filling device, and this vacuum tank exerts a gas-liquid separation function. This prevents the vacuum pump from absorbing water.
[0006]
[Patent Document 1]
JP-A-2002-206494 (FIG. 1)
[Patent Document 2]
JP-A-2002-138982 (FIG. 1)
[0007]
[Problems to be solved by the invention]
In a structure in which a sufficient rising portion is provided in the intake pipe as in the pump in Patent Document 1, a rising portion having a height equal to or higher than the pumping height of the pump is required. The pumping height at a general pumping pump station where a pumping pump is installed is, for example, about 6 m. Therefore, it is necessary to provide a rising portion at 6 m or more. As a result, the building of the pumping station is enlarged, which may lead to a significant cost increase.
[0008]
On the other hand, a method of preventing water absorption by interposing a vacuum tank having a gas-liquid separation function as in the case of a water pump in Patent Literature 2 allows the structure to be compact. However, there are still problems with this method. That is, there is an unstable factor in preventing water absorption of the vacuum pump. That is, in a system using a vacuum tank having a gas-liquid separation function, if a large amount of water enters the vacuum tank and the gas-liquid separation function does not work sufficiently, the vacuum pump may absorb water. Therefore, in the pump of Patent Document 2, a full-water detecting unit is provided, and when the full-water detecting unit detects that the pump casing is full, the vacuum pump is stopped to prevent a large amount of water from entering the vacuum tank. Like that. By the way, in order to guarantee the reliable operation of such a mechanism, a high-precision water level sensor or the like used for the full water detecting means is required. However, when the full water detecting means operates, it often comes into contact with muddy water. As a result, once activated, there is a high possibility that a failure factor will be carried. If the full-water detecting means breaks down during the next pumping operation, the vacuum pump continues to operate even after the pump casing is full, and a large amount of water enters the vacuum tank. There is a risk of failure while the operation is continued. This is a major problem for water pumps. In other words, pumps are often used in emergency situations as drainage pumps, such as drainage in the event of floods. Is required.
[0009]
The present invention has been made in view of the above-described conventional circumstances, and its object is to provide a water-filling device using a dry vacuum pump, which increases the economical efficiency of the entire device, and reduces the number of failure factors when required. It is an object of the present invention to provide a water filling device with high operation reliability and to provide a pumping pump station using the same.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, in the present invention, at the start of pumping by the pump, the pump is used to form a negative pressure state for filling water in the pump casing of the pump, and the dry type for forming the negative pressure state is used. In a water filling device including a vacuum pump, a first full water detecting means is provided near the pump casing, and a second full water detecting means is provided between the first full water detecting means and the vacuum pump. When the first full state detecting means does not detect the full state of the pump casing, the second full state detecting means can detect the full state of the pump casing.
[0011]
Further, in the present invention, the above-mentioned water filling device is provided with a buffer tank capable of storing the water sucked up together with the suction air flow by the vacuum pump from the air flow, and using the buffer tank to make the second tank. Is formed.
[0012]
According to the present invention, in the above-described water filling device, a drying operation of the vacuum pump can be performed after the water filling state of the pump casing is detected.
[0013]
In the present invention, a dry two-stage roots vacuum pump is used as the vacuum pump in the above-described water filling device.
[0014]
In order to achieve the above and other objects of the present invention, in a pumping station provided with a plurality of pumps, a part of the above-described water filling device is shared by the plurality of pumps, and Regarding partial sharing, the downstream side of the separation valve provided in the water filling device is shared, and the separation valve and the upstream side thereof are provided for each of the plurality of pumps.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described. FIG. 1 schematically shows a configuration of a water pump according to one embodiment, which uses a water filling device as an auxiliary device. The pump shown in the figure is a horizontal axis pump. The pump shown in the figure is an example used to discharge water sucked from the suction water tank 11 to the discharge water tank 12. The pump has a pump casing 13. A suction pipe 15 is connected to the upstream side of the pump casing 13 via a suction elbow 14, and a suction port 16 at a distal end of the suction pipe 15 is configured to sink below the water surface of the suction water tank 11. On the other hand, a discharge pipe 17 is connected to the downstream side of the pump casing 13, and a discharge port 18 at the distal end of the discharge pipe 17 is configured to sink below the surface of the discharge water tank 12. The pump casing 13 has a pump impeller 19 incorporated therein. The pump impeller 19 is fixed to one end of a main shaft 20 penetrating the wall of the suction elbow 14 in the lateral direction. On the other hand, the other end of the main shaft 20 is connected to a drive motor 22 via a speed reducer 21. Here, a configuration in which a discharge valve is provided on the downstream side of the pump casing 13 is also possible. In this case, a discharge valve is provided via a loose short pipe, and the discharge pipe 17 is connected to the discharge valve.
[0016]
The water filling device is connected to a water pump via an opening 31 provided in an upper part of the pump casing 13. This water filling device is provided with a first water filling detecting means 32, a buffer tank 33, a strainer 34, a check valve 35, and a dry vacuum pump 36 which are sequentially connected and arranged by piping from the pump casing 13 side. .
[0017]
The first full-water detection means 32 has a structure in which a detection unit 37 using, for example, a water level sensor is attached to a full-water detection container 38. The detection unit 37 is electrically connected to the control unit 39 by a signal line shown by a dotted line, and transmits a detection signal to the control unit 39 when the pump casing 13 is full as described below. On the other hand, a first vacuum break valve 40 is connected to the full water detection container 38 as vacuum breaking means for breaking a negative pressure state formed by the vacuum pump 36 therein.
[0018]
The buffer tank 33 basically has two functions. One of them is to prevent the vacuum pump 36 from absorbing water that has intruded beyond the fullness detection container 38 in the first fullness detection means 32 together with the airflow sucked by the vacuum pump 36. It is a buffer for separating water from water and has the necessary capacity and shape. Specifically, a circular cross section having a size capable of separating water by rapid expansion from an air flow containing water flowing into the buffer tank 33 through the pipe Pa connected from the full water detection container 38 to the body of the buffer tank 33. In the form of a vertically long container. Another function is a function as the second fullness detecting means 42 for backing up the first fullness detecting means 32. That is, the buffer tank 33 functions in the same manner as the full-water detection container 38 in the first full-water detecting means 32, and the detecting section 42 s attached to the body of the buffer tank 33 includes the detecting section 37 in the first full-water detecting means 32. Works the same as.
[0019]
A separation valve 41 having a function as described below is connected to the buffer tank 33 via a pipe Pa, and a second vacuum break valve 43 serving as a vacuum breaking means of the buffer tank 33 is connected thereto. A drain valve 44 for extracting water accumulated in the tank 33 is connected.
[0020]
The strainer 34 prevents the vacuum pump 36 from sucking foreign matter together with the suctioned air. The check valve 35 functions to maintain a negative pressure state upstream of the check valve 35 when the vacuum pump 36 abnormally stops during its operation.
[0021]
As the first vacuum break valve 40, the separation valve 41, the second vacuum break valve 43, and the drain valve 44, electric valves are used. These motor-operated valves are electrically connected to the control means 39 by signal lines, respectively, to supply the respective open / closed state signals to the control means 39, and to control the respective open / close operation signals from the control means 39. Control by means 39 is provided.
[0022]
The control unit 39 receives a signal from the first full state detecting unit 32 or the second full state detecting unit 42, and operates the vacuum pump 36 or opens and closes each of the electric valves by, for example, a sequence control by a relay or a sequencer. Control the operation and so on. The details will be described later. Although not shown, the vacuum pump 36, the control means 39, and each of the above-mentioned electric valves are connected to a power source for power supply by electric wires.
[0023]
Hereinafter, the operation control of the water filling device and the water pump with the above configuration will be described. FIG. 2 shows a flow of processing in the operation control. In step 101, operation is started. The initial state of the water filling device at the start of operation is as follows: equipment abnormality: none, vacuum pump 36: stop, first full water detecting means 32: not detected, second full water detecting means 42: not detected, separation valve 41: The state is closed, the first vacuum break valve 40 is open, the second vacuum break valve 43 is open, and the drain valve 44 is open. Operation is started after this initial state is confirmed. When the operation is started, the operations of closing the first vacuum break valve 40, the second vacuum break valve 43, and the drain valve 44 are simultaneously performed in parallel steps 102 to 104. These are AND conditions. If these conditions are satisfied, the opening operation of the separation valve 41 is performed in step 105, and the downstream side and the upstream side of the separation valve 41 communicate with each other. Here, the “downstream side” and “upstream side” with respect to the separation valve 41 are based on the air flow during suction by the vacuum pump 36, and the downstream side is the vacuum pump 36 side, and the upstream side Is on the first full water detecting means 32 side. In step 106, the vacuum pump 36 is started for a water filling operation. Due to the operation of the vacuum pump 36 for filling the water, the buffer tank 33, the full water detecting container 38, and the pump casing 13 of the water pump are brought into a negative pressure state, and the pump casing 13 draws water from the suction tank 11 accordingly. Then, when the pump casing 13 becomes full, water is also sucked up into the full-water detecting container 38 of the first full-water detecting means 32, and the detection is performed by the detecting unit 37 to detect the full water.
[0024]
Steps 107 and 108 are both processes for judging whether or not water is full, and are performed in parallel. In step 107, it is determined whether or not the first full water detecting means 32 detects the full water. If the first full water detecting means 32 has detected that water is full, this is transmitted to the control means 39. The control means 39 which has received the detection of the full water counts a predetermined time by a timer. In step 109, it is determined whether or not the predetermined time has been counted. The reason why such a process is provided is that even if the pump casing 13 is not full, water may jump up into the fullness detection container 38 and the detection unit 37 may detect such a possibility that a malfunction may occur. This is because an appropriate cushion is placed from when the full pump is detected until the vacuum pump 36 is stopped. If it is determined in step 109 that the predetermined time has been counted, in step 110, the vacuum pump 36 is stopped.
[0025]
On the other hand, in step 108, it is determined whether or not the second full state detecting means 42 has detected the full state. Normally, when the pump casing 13 becomes full, the first full-water detecting means 32 detects this as described above, and the vacuum pump 36 is stopped. However, the first full water detecting means 32 may not operate normally due to a failure or the like. In this case, even if the full-water detection container 38 is filled with water, the vacuum pump 36 does not stop and the suction of water to the water-filling device side continues, and the water reaches the buffer tank 33. Then, when the water level of the buffer tank 33 reaches the detection unit 42s, the detection is detected by the detection unit 42s. This is the detection of fullness by the second fullness detection means 42. The detection of fullness by the fullness detection means 42 and the detection of fullness by the first fullness detection means 32 + counting of a predetermined time are OR conditions, and if any of the conditions is satisfied, the vacuum pump 36 is stopped in step 110. .
[0026]
When the vacuum pump 36 stops, the separation valve 41 is closed in step 111, whereby the downstream side and the upstream side separated by the separation valve 41 are separated. Following the closing of the separation valve 41, there are steps 112 to 114 that are processed in parallel. In step 112, the water pump is started to start pumping. In step 113, the second vacuum break valve 43 is opened and the inside of the buffer tank 33 is set to atmospheric pressure. In step 114, the drain valve 44 is opened and the buffer is opened. The water stored in the tank 33 is discharged under natural flow. Completion of the discharge of the stored water from the buffer tank 33 is performed by counting a predetermined time by a timer in the control means 39. The predetermined time count is determined in step 115. The counting of the predetermined time and the opening of the second vacuum break valve 43 are AND conditions. When this condition is satisfied, the vacuum pump 36 is started for the drying operation in step 116. This drying operation is continued for a predetermined time set by the timer in the control means 39. Therefore, it is determined in step 117 whether or not the predetermined time has been counted. If it is determined that the predetermined time has been counted, the drying operation of the vacuum pump 36 is stopped in step 118. The drying of the vacuum pump 36 is performed by self-heating by the drying operation of the vacuum pump 36.
[0027]
On the other hand, if the pumping by the pump is completed during this time, the pump is stopped in step 119. Then, the opening of the first vacuum break valve 40 was performed in step 120, and the pump casing 13 was filled with the stop of the pump and the satisfaction of the AND condition of the predetermined time count + the opening of the vacuum break valve 43 as an AND condition. Water falls into the suction tank 11. Then, the operation is completed with the opening of the vacuum break valve 40 and the stop of the drying operation of the vacuum pump 36 as an AND condition (step 121).
[0028]
In the above operation control, the discharge of water from the buffer tank 33 is determined by counting the time. Instead, a water level switch and a water level sensor are provided in the buffer tank 33, and the water level switch and the water level sensor are provided. It is also possible to adopt a form in which the discharge of water is determined by the method.
[0029]
In the above embodiment, in addition to the first full water detecting means 32 provided near the pump casing 13 of the water pump, the second full water detecting means 42 using the buffer tank 33 is provided. For this reason, even if a failure occurs in the first full-water detecting means 32 and the full-water detection cannot be performed, the second full-water detecting means 42 can back up the water, and the danger of the vacuum pump 36 absorbing water is greatly reduced. Can be reduced. Therefore, according to the present embodiment, it is possible to greatly increase the operation reliability of the water filling device using the dry-type vacuum pump 36 when necessary, and also to greatly increase the operation reliability of the water pump when necessary. it can. After the operation for filling the vacuum pump 36 is stopped, the pumping operation of the water pump is performed in a state where the downstream side and the upstream side are separated by the separation valve 41, and the drying operation of the vacuum pump 36 is performed during the operation. Is made sufficiently dry, and the operation is terminated on this condition. Therefore, even if moisture enters the vacuum pump 36 during operation, it does not remain, and a failure factor that may occur due to rust or the like generated inside the vacuum pump 36 while the pump is stopped. Can be eliminated. This also makes it possible to further increase the operational reliability of the water filling device when necessary. Further, according to the present embodiment, the second full-water detecting means 42 is formed using the buffer tank 33 for preventing water absorption of the vacuum pump 30, so that the apparatus can be made compact.
[0030]
Next, a preferred type of dry vacuum pump applied to the vacuum pump 36 will be described. Table 1 shows the results of comparison of the price, installation area, and drive motor capacity of a water ring vacuum pump, a dry side channel vacuum pump, and a dry two-stage roots vacuum pump each having the same suction performance. . As can be seen, the dry type two-stage roots type vacuum pump has the same drive motor capacity as the price and installation area, even if not comparable to the water ring type vacuum pump. Considering the reduction, it is sufficiently economical. In addition, a dry two-stage roots vacuum pump does not cause a failure immediately even if water is absorbed if the amount is small, and it can be said that this is superior to a dry side channel vacuum pump which is extremely weak against water. Therefore, it is most preferable to use a dry two-stage roots vacuum pump as the dry vacuum pump 36 in the water filling device of FIG.
[Table 1]

[0031]
Hereinafter, the performance comparison between the water ring vacuum pump and the dry two-stage roots vacuum pump will be described for reference. FIG. 3 is a graph comparing the performance of a water ring vacuum pump and a dry two-stage roots vacuum pump at the same drive motor capacity. The horizontal axis is the negative pressure, and the vertical axis is the intake air volume. As can be seen from this comparison, at the same drive motor capacity, the dry two-stage roots vacuum pump D can substantially cover the suction air volume of the water ring vacuum pump W, and can be used instead of the water ring vacuum pump. Therefore, it is possible to configure a water filling device having sufficient performance.
[0032]
Next, an embodiment in a case where the water filling device according to the present invention is applied to a pumping pump station provided with a plurality of pumping pumps will be described. When applying the water filling device according to the present invention to a plurality of water pumps, a method of providing one water filling device for each water pump and a method of partially filling the water filling device to perform a water filling operation of the plurality of water pumps. Is possible. In the case where one water filling device is provided for each water pump, it is the same as arranging the configuration of FIG. 1 in parallel. In this case, there is an advantage that the water filling operation can be simultaneously performed on a plurality of pumps. On the other hand, in the system in which the water filling device is partially shared, although the water filling operation is sequentially performed on a plurality of water pumps, there is an advantage that the cost of the whole water pumping station can be significantly reduced. When the water filling device according to the present invention is partially shared, in the case of the water filling device of FIG. 1, the downstream side of the separation valve 41 is shared, and the separation valve 41 and the upstream side thereof are provided for each pump. It is preferable to provide such an arrangement. In the water filling operation in this embodiment, a water filling operation is sequentially performed on a plurality of water pumps in accordance with the operation control process of FIG. 2, and after all the water pumps are completed, a drying operation of the vacuum pump 36 is performed. Become. The opening of the first vacuum break valve 40 performed after the stop of the pumps may be performed for each of the pumps, or may be performed simultaneously for all the pumps after the stop of the pumps. Is also good.
[0033]
【The invention's effect】
As described above, in the present invention, in addition to the first fullness detecting means provided near the pump casing of the water pump, the second fullness detecting means is provided downstream thereof. For this reason, even if a failure occurs in the first fullness detecting means and the fullness detection cannot be performed, the second fullness detecting means can provide a backup, thereby greatly reducing the danger of the vacuum pump absorbing water. Can be. Therefore, according to the present invention, the operation reliability of the water filling device using the dry vacuum pump when required can be greatly increased, and the operation reliability of the water pump when required can also be greatly increased.
[Brief description of the drawings]
FIG. 1 is a diagram schematically illustrating a configuration of a water filling device according to an embodiment of the present invention and a water pump to which the device is applied.
FIG. 2 is a flowchart illustrating a flow of processing in operation control of the water filling device and the water pump of FIG. 1;
FIG. 3 is a graph showing a performance comparison between a water ring vacuum pump and a dry two-stage roots vacuum pump.
[Explanation of symbols]
13 pump casing 32 first fullness detecting means 33 buffer tank 36 vacuum pump 41 separation valve 42 second fullness detecting means

Claims (5)

A water filling device which is used to form a negative pressure state for filling water in a pump casing of the water pump at the start of pumping by the water pump and includes a dry vacuum pump for forming the negative pressure state. A first full-water detecting means is provided adjacent to the pump casing, and a second full-water detecting means is provided between the first full-water detecting means and the vacuum pump, and the pump casing is provided by the first full-water detecting means. A water filling state detecting means for detecting a water filling state of the pump casing by the second water detecting means when the water filling state is not detected. 2. The second fullness detecting means according to claim 1, wherein a buffer tank capable of separating and storing water sucked up together with the suction air flow by the vacuum pump from the air flow is provided, and the buffer full tank is used to form the second full water detecting means. Water filling device. 3. The water filling device according to claim 1, wherein the vacuum pump performs a drying operation after the detection of a water filling state of the pump casing. 4. The water filling device according to any one of claims 1 to 3, wherein a dry two-stage roots vacuum pump is used as the vacuum pump. In a pumping station where a plurality of pumps are installed, a part of the water filling device according to any one of claims 1 to 4 is shared by the plurality of pumps, and a part thereof is shared. The pumping station according to claim 1, wherein a downstream side of the separation valve provided in the water filling device is shared, and the separation valve and an upstream side thereof are provided for each of the plurality of pumps.

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