JP2002138982A - Horizontal shaft pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a horizontal shaft pump capable of removing water from a water filling device filling water in a pump casing 10 using a dry vacuum pump 70. SOLUTION: An opening part 38 is provided in an upper part of the pump casing 10 or a suction elbow 12 or a loose short pipe 20, and the opening part 38 is arranged and communicated with a vacuum tank 60 through a water filling detection means 40 and a vacuum shut-off valve 42 and the vacuum tank 60 is arranged and communicated with the dry vacuum pump 70 to constitute the water filling device. When full filling of water is detected by the water filling detection means 40, the vacuum shut-off valve 42 is closed by a control means 52 and the operation of the dry vacuum pump 70 is stopped. The vacuum tank 60 has a large cross sectional area when compared with a cross sectional area of a flow passage in a pipe. Moreover, a filter 64 preventing passing of dust is provided at a position in an upper part in the vacuum tank 60 where gas separated from liquid passes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a horizontal pump which constitutes a water filling device for filling a pump casing with water by using a dry vacuum pump.

[0002]

2. Description of the Related Art An example of a conventional horizontal shaft pump will be described with reference to FIGS. FIG. 5 is an overall configuration diagram of a conventional horizontal shaft pump including a water filling device for filling a pump casing with water. FIG. 6 is a diagram illustrating a structure of an example of a full water detecting unit.

[0003] In FIG. 5, a horizontal axis pump is provided with a suction pipe 1 via a suction elbow 12 upstream of a pump casing 10.
4, a suction port 16 at the tip end of the suction pipe 14 is immersed below the surface of the suction water tank 18, and a discharge valve 22 is provided downstream of the pump casing 10 via a loose short pipe. A discharge pipe 24 communicates with the valve 22, and a discharge port 26 at the tip of the discharge pipe 24 is immersed below the water surface of a discharge water tank 28. Then, the main shaft 30 passes through the wall of the suction elbow 12 in the horizontal direction. A pump impeller 32 is fixed to one end of the main shaft 30 and is rotatably disposed in the pump casing 10, and the other end is drivingly connected to an electric motor 36 via a speed reducer 34.

An opening 38 is formed in the upper part of the pump casing 10 so that the opening 38
The full-water detecting means 40 is connected to a liquid-ring vacuum pump 44 via a vacuum shut-off valve 42. Then, a pipe connecting the full-water detecting means 40 and the vacuum shut-off valve 42 is branched, and a vacuum break valve 46 for connecting the pipe to the atmosphere is provided. Further, the liquid ring vacuum pump 44 is supplied with water for liquid ring from a water storage tank 50 appropriately supplied with a water supply pump 48. Further, when a signal indicating that water is full is given from the full-water detecting means 40, the control means 52 closes the vacuum shut-off valve 42 and sets the liquid-ring vacuum pump 44
Stop the operation of.

The full-water detecting means 40 has two parallel electrodes 54, 54, as shown in FIG. 6, and the two electrodes 54, 54 are immersed in water and become conductive, so that the full water is detected. Detection is performed. The opening 38, the full-water detecting means 40, the vacuum shut-off valve 42, the liquid-ring vacuum pump 44, and the control means 52 constitute a full-water device.

In the horizontal shaft pump having such a configuration, the operation of the liquid ring vacuum pump 44 is started when the vacuum shut-off valve 42 is opened and the vacuum breaking valve 46 is closed. Then, the air in the pump casing 10 is sucked out, the inside of the pump casing 10 becomes a negative pressure, and the water in the suction water tank 18 is sucked into the pump casing 10 through the suction pipe 14 and the suction elbow 12. And the pump casing 10
Is filled with water, and the electrodes 54,
When the water is conducted and the full state is detected, the control means 52 closes the vacuum shut-off valve 42 and stops the operation of the liquid ring vacuum pump. In this manner, the pump casing 10 is filled with water, the electric motor 36 is driven to rotate the pump impeller 32, and the pumping operation is performed.

After the pumping operation is completed, the vacuum break valve 4
When opening 6, the water in the pump casing 10 falls. The control of the discharge valve 22 at the time of starting the operation is different depending on the type of the horizontal axis pump. For example, in the case of a mixed flow pump, the water filling operation is performed with the discharge valve 22 closed, and the pump is opened after the pumping operation is started. In the case of an axial flow pump,
The water filling operation is performed with the discharge valve 22 opened.

[0008]

In the above conventional structure, a liquid ring type is used as a vacuum pump. This is because the vacuum pump often sucks moisture and dust together with the air inside the pump casing 10 when performing a water filling operation inside the pump casing 10. This is because the performance is not damaged. However, the use of the liquid ring vacuum pump requires water for liquid sealing such as the water storage tank 50 and the water supply pump 52.

In recent years, in order to enhance the reliability of a pump station, auxiliary equipment having a structure not including a water system, such as a non-water supply shaft sealing device for a main pump and an air-cooled speed reducer, has been tending to be adopted. This is the so-called dehydration of the pump station. This is to prevent the main pump from becoming inoperable due to a failure of the auxiliary equipment due to water cutoff or the like in a disaster or the like as much as possible.

The present invention has been made in view of the above-mentioned demand for dehydration of a pumping station, and has as its object to provide a horizontal shaft pump capable of performing a water filling operation using a dry vacuum pump.

[0011]

In order to achieve the above object, a horizontal shaft pump according to the present invention is provided with an opening in an upper part of a pump casing or a suction elbow or a loose short pipe connected to the pump casing. The opening is communicated with a dry vacuum pump through a gas-liquid separation means through a pipe to form a water filling device.

The opening is communicated with a full-water detecting means, and the full-water detecting means is communicated with a pipe to the gas-liquid separating means via a vacuum shut-off valve, and the gas-liquid separating means is communicated with a pipe to the dry vacuum pump. When the full-water detecting unit detects that the water is full, the control unit closes the vacuum shut-off valve and stops the operation of the dry vacuum pump.

Further, the opening is communicated with a full-water detecting means, the full-water detecting means is communicated with a pipe to the gas-liquid separating means, and the gas-liquid separating means is communicated with a pipe to the dry vacuum pump via a vacuum shut-off valve. When the full level is detected by the full level detecting means, the vacuum shutoff valve may be closed by the control means and the dry vacuum pump may be stopped.

Further, a plurality of horizontal axis pumps are provided, and the openings provided in the plurality of horizontal axis pumps are respectively communicated with full water detecting means, and these full water detecting means are connected to vacuum shut-off valves respectively. A pipe is connected to one of the gas-liquid separation means via a pipe, and the gas-liquid separation means is connected to the dry vacuum pump via a pipe. The control means operates the dry vacuum pump and controls any one of the vacuum shut-off valves. When the full state is detected by the fullness detecting means to which the opened vacuum shutoff valve communicates, the vacuum shutoff valve is closed, and one of the other vacuum shutoff valves is opened, and sequentially The plurality of horizontal shaft pumps may be filled one by one, and when all the horizontal shaft pumps are full, the open vacuum shut-off valve may be closed and the dry vacuum pump may be shut down. .

Further, a plurality of horizontal axis pumps are provided, and the openings provided in the plurality of horizontal axis pumps are respectively communicated with full water detecting means, and these full water detecting means are connected to the vacuum shut-off valve and the air pump. A pipe is connected to one of the dry vacuum pumps via liquid separation means, and the control means operates the dry vacuum pump and opens any one of the vacuum shut-off valves. When fullness is detected by the full-water detecting means to which the shut-off valve communicates, the vacuum shut-off valve is closed and one of the other vacuum shut-off valves is opened to sequentially connect the plurality of horizontal shaft pumps to one. When the horizontal axis pumps are full, the open vacuum shut-off valve is closed and the dry vacuum pump is shut down.

The gas-liquid separating means may be constituted by a vacuum tank having a larger cross-sectional area than the flow-path cross-sectional area of the inflow-side pipe communicating with the gas-liquid separating means.

Further, it is possible to provide a filter between the dry vacuum pump and the gas-liquid separation means for preventing the passage of dust.

Further, a filter for blocking the passage of dust may be provided at a position in the upper portion of the vacuum tank through which the gas from which the liquid is separated passes.

[0019]

FIG. 1 shows a first embodiment of the present invention.
This will be described with reference to FIG. FIG. 1 is an overall configuration diagram of a horizontal shaft pump provided with a water filling device for filling a pump casing according to a first embodiment of the present invention. In FIG. 1, members that are the same as or equivalent to those in FIG. 5 are given the same reference numerals, and redundant description is omitted.

In the horizontal shaft pump of the present invention shown in FIG.
The differences from the conventional structure shown in FIG. 5 are as follows. The opening 38 at the upper part of the pump casing 10 is communicated with a full-water detecting means 40, and the full-water detecting means 40 is connected to a vacuum tank 60 as a gas-liquid separating means via a vacuum shut-off valve 42. The vacuum tank 60 has, for example, a cylindrical shape that is long in the up-down direction, and the cylindrical cross-sectional area is considerably larger than the flow-path cross-sectional area of the inflow-side pipe that is communicated with the
It is configured such that the sucked air enters the vacuum tank 60 and the flow velocity rapidly decreases. The vacuum tank 60
A pipe from a vacuum shut-off valve 42 communicates and opens to a substantially central side wall in the vertical direction. The bottom of the vacuum tank 60 is a reservoir for the separated water, and the bottom is the drain valve 6.
It is communicated to the atmosphere via 2. A filter 64 for blocking the passage of dust is provided at an upper portion in the vacuum tank 60, and an upper end thereof is connected to a dry vacuum pump 70 via a check valve 66 and a suction valve 68. Furthermore, the vacuum tank 6
A pipe that communicates between the zero and the check valve 66 is branched and communicated with the atmosphere via the open valve 72. Control means 5
When a full-water detection signal is given from the full-water detection means 40, the second shuts off the vacuum shut-off valve 42 and stops the operation of the dry vacuum pump 70.

In this configuration, the dry vacuum pump 70 is operated with the vacuum breaking valve 46, the drain valve 62, and the opening valve 72 closed and the vacuum shut-off valve 42 and the suction valve 68 opened. Then, the pump casing 10
The air inside is first sucked into the vacuum tank 60. Here, since the flow velocity sharply decreases in the vacuum tank 60, liquid such as water mixed in the air falls downward in the vacuum tank 60 and accumulates at the bottom, and the air and the water are separated. Further, the dust contained in the air is prevented from passing by the filter 64. Then, from the upper end of the vacuum tank 60, clean air from which water and dust have been removed is sucked by the dry vacuum pump 70. In this way, the air in the pump casing 10 is sucked out to have a negative pressure, and water is sucked into the pump casing 10 to be full. It is assumed that the operation of the dry vacuum pump 70 is not completely stopped until the inside of the pump casing 10 becomes full, and until the full state is detected by the full-water detecting means 40 and the vacuum shut-off valve 42 is completely closed. In addition, water is easily sucked into the vacuum tank 60 instead of air. However, since air and water are completely separated in the vacuum tank 60, no water is sucked into the dry vacuum pump 70.

Therefore, in the horizontal axis pump according to the present invention, the water is separated from the air to be sucked by using the vacuum tank 60 as the gas-liquid separating means, and the dust is removed by the filter 64. The pump 70 does not draw water and dust and does not cause a failure or the like. As a result, the horizontal pump can be filled with water using the dry vacuum pump 70, and the auxiliary equipment required for filling can be dehydrated.

Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 2 is an overall configuration diagram of a plurality of horizontal shaft pumps provided with a water filling device for filling a pump casing according to a second embodiment of the present invention. 2, the same or equivalent members as those in FIG. 1 are denoted by the same reference numerals, and redundant description will be omitted.

In the second embodiment shown in FIG. 2, a plurality of horizontal shaft pumps 80a, 80b, 80c are provided, and the full water detecting means 40a, 40b, 40c are provided in the respective openings provided in the upper portions of these pump casings. Are communicated with each other. These full water detection means 40a, 40b, 40c
The piping is connected to one vacuum tank 60 via the vacuum shut-off valves 42a, 42b, and 42c. In addition, the full-water detecting means 40a, 40b, 40c and the vacuum shutoff valves 42a,
The pipes between 2b and 42c are branched off and communicate with the atmosphere via vacuum break valves 46a, 46b and 46c, respectively. Then, the full water detecting means 40a, 40b, 4
0c is supplied to the control means 52, and the control means 52 supplies the signals to the vacuum shutoff valves 42a, 42a,
2b, 42c and the dry vacuum pump 70 are supplied with signals, respectively.

In such a configuration, the control means 52 first opens one vacuum cutoff valve 40a, and opens the other vacuum cutoff valve 4a.
The operation of the dry vacuum pump 70 is performed in a state where 0b and 40c are closed. Then, the air in the pump casing of the horizontal shaft pump 80a to which the opened vacuum shut-off valve 42a communicates is sucked out, and the water is sucked in as a negative pressure. And
When the inside of the pump casing becomes full, the full-water detecting means 40
a outputs a signal to the control means 52. The control means 52 to which this signal is given is operated by the open vacuum shut-off valve 42.
a and close the other vacuum shut-off valve 42b. Therefore, the horizontal shaft pump 80b to which the newly opened vacuum shut-off valve 42b communicates is now full of water. Then, similarly, the opened vacuum cutoff valve 42b is closed, and another vacuum cutoff valve 42c that has not been opened is opened, and the horizontal shaft pump 80c to which this is communicated is filled with water. When the water is full, the vacuum shut-off valve 4 that has been opened
Block 2c. In addition, all the horizontal shaft pumps 80a, 80
When it is determined that b and 80c are full, the control means 52 stops the operation of the dry vacuum pump 70.

In the second embodiment, a plurality of horizontal pumps 80a, 80b, 80c can be filled with one dry vacuum pump 70.

Further, a third embodiment of the present invention will be described with reference to FIG. FIG. 3 is an overall configuration diagram of a plurality of horizontal shaft pumps provided with a water filling device for filling a pump casing according to a third embodiment of the present invention. 3, the same or equivalent members as those in FIGS. 1 and 2 are denoted by the same reference numerals, and redundant description will be omitted.

The third embodiment shown in FIG. 3 differs from the second embodiment shown in FIG. 2 in the following points. The vacuum shut-off valves 42a, 42b, 42c respectively connected to the horizontal axis pumps 80a, 80b, 80c are not one vacuum tank but vacuum tanks 60a, 60b, 60
c, and these vacuum tanks 60a, 60
b and 60c are connected to a single dry vacuum pump 70 by piping.

In such a configuration, the horizontal shaft pump 80
a, 80b, 80c, the vacuum tanks 60a, 60b, 6
0c are provided and the respective vacuum tanks 60a, 60
b and 60c need only have a small capacity to separate water, and can be downsized accordingly. And the vacuum shut-off valve 4
By closing the 2a, 42b, 42c, the vacuum tank 6
No water is sucked into or flowed into 0a, 60b, 60c.

FIG. 4 shows a fourth embodiment of the present invention.
This will be described with reference to FIG. FIG. 4 is an overall configuration diagram of a plurality of horizontal shaft pumps provided with a water filling device for filling a pump casing according to a fourth embodiment of the present invention. 4, the same or equivalent members as those in FIGS. 1 to 3 are denoted by the same reference numerals, and redundant description will be omitted.

The fourth embodiment shown in FIG. 4 differs from the third embodiment shown in FIG. 3 in that a vacuum shut-off valve 42 connected to each of the horizontal pumps 80a, 80b, 80c is provided.
a, 42b, 42c and vacuum tanks 60a, 60b, 60
This is because the order of piping with c is changed and the piping is communicated. For example, a full-water detecting means 40a communicating with an opening provided in the horizontal axis pump 80a is connected to the vacuum tank 60a by a pipe, and the vacuum tank 60a is connected to the vacuum shut-off valve 42a.
Is connected to the pipe. Then, each vacuum shut-off valve 42
The pipes a, 42b, and 42c communicate with one dry vacuum pump 70.

In such a configuration, the vacuum shut-off valve 42
a, 42b and 42c are closed, so that the vacuum tank 60
The a, 60b, and 60c are cut off from the dry vacuum pump 70, and there is no danger that moisture or the like separated and accumulated in the vacuum tanks 60a, 60b, and 60c is sucked into the dry vacuum pump 70.

In the above-described embodiment, the cylindrical vacuum tank 60 having a large cross-sectional area is used as the gas-liquid separating means. However, the present invention is not limited to this, and an in-line type vacuum tank may be used. Any other means may be used as long as the separated water can be reliably separated.
In addition, the filter 64 is provided in the upper part in the vacuum tank 60, but is not limited to this, and may be independently provided in a piping route to the dry vacuum pump 70. If the filter 64 is interposed independently, the filter 64
Maintenance is easy.

Further, the opening 38 for sucking out the air in the pump casing 10 is not limited to the one formed in the upper part of the pump casing 10 but the pump casing 1
The upper part of the suction elbow 12 connected to the upstream side of the pump casing 10 or the upper part of the loose short pipe 20 connected to the downstream side of the pump casing 10 may be formed. And the opening 38
The number of holes is not limited to one, and a plurality of holes may be formed, and their openings may be connected to each other so as to be combined into one pipe and communicated with the full water detecting means 40. In addition, the full water detecting means 4
No. 0 may be any structure as long as it can detect that the pump casing 10 is full and output an appropriate signal.

[0035]

As described above, since the horizontal shaft pump of the present invention is constituted, the following special effects can be obtained.

In the horizontal axis pump according to the first aspect, the water mixed with the air to be sucked is separated by the gas-liquid separating means, so that the water is not sucked into the vacuum pump for sucking the air. A dry vacuum pump can be used.
Therefore, the auxiliary equipment for the water filling operation can be dehydrated without requiring the supply of water.

In the horizontal axis pump according to the second or third aspect, when the pump casing becomes full due to the water filling operation, this is detected by the water full detecting means, the vacuum shut-off valve is closed, and the dry vacuum pump is used. Is stopped, so that the dry vacuum pump does not continue to be operated more than necessary after the pump casing is filled with water. Therefore, if the vacuum pump is continuously operated more than necessary, air in which a large amount of liquid is mixed is sucked in, and water cannot be sufficiently separated by the gas-liquid separation means, which may cause a problem such as water being sucked into the vacuum pump. There is no.

Further, in the horizontal axis pump according to claim 4 or 5, a plurality of horizontal axis pumps can be filled with water using one dry vacuum pump.

In the horizontal axis pump according to the sixth aspect, the gas-liquid separation means is constituted by a vacuum tank having a larger cross-sectional area than the flow path cross-sectional area of the inflow side pipe.
Its structure is simple.

Furthermore, in the horizontal axis pump according to the present invention, since the dust contained in the air is removed by the filter, the dust is not sucked into the dry vacuum pump and the dust is damaged by the suction of the dust. There is no.

Further, in the horizontal axis pump according to the present invention, since the filter is provided at the upper part in the vacuum tank as the gas-liquid separating means, both water and dust are separated from the air in the vacuum tank. You. In addition, the gas-liquid separating means and the filter are integrally formed in the vacuum tank, and the number of pipes is reduced accordingly.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a horizontal shaft pump provided with a water filling device for filling a pump casing with water according to a first embodiment of the present invention.

FIG. 2 is an overall configuration diagram of a plurality of horizontal shaft pumps provided with a water filling device that fills a pump casing according to a second embodiment of the present invention.

FIG. 3 is an overall configuration diagram of a plurality of horizontal shaft pumps provided with a water filling device that fills a pump casing according to a third embodiment of the present invention.

FIG. 4 is an overall configuration diagram of a plurality of horizontal shaft pumps including a water filling device for filling a pump casing according to a fourth embodiment of the present invention with water;

FIG. 5 is an overall configuration diagram of a conventional horizontal shaft pump including a water filling device for filling a pump casing with water.

FIG. 6 is a diagram illustrating an example of a full water detecting unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Pump casing 12 Suction elbow 20 Loose short pipe 38 Opening 40, 40a, 40b, 40c Fullness detection means 42, 42a, 42b, 42c Vacuum shutoff valve 52 Control means 60, 60a, 60b, 60c Vacuum tank 64 Filter 70 Dry vacuum Pump 80a, 80b, 80c Horizontal axis pump

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hideki Kage 1-2-1, Koya-cho, Kurume-shi, Fukuoka Prefecture Inside the Chikugogawa Construction Office, Kyushu Regional Development Bureau, Ministry of Land, Infrastructure, Transport and Tourism 1-2-1, Koya-cho, Kyushu-shi Ministry of Land, Infrastructure and Transport Kyushu Regional Development Bureau Chikugo River Construction Office (72) Inventor Takeyuki Omura 1-2-1, Koya-cho, Kurume-shi, Fukuoka Pref. Chikugo River Construction Office (72) Inventor Shoji Otsuka 2-22-15 Akasaka, Minato-ku, Tokyo In-house River Pumping Equipment Association (72) Inventor Michiaki Negishi 1-5-5 Omorikita, Ota-ku, Tokyo No. 1 Inside Dengyosha Machinery Works (72) Inventor Toshiaki Yamamoto 1-5-1, Omorikita, Ota-ku, Tokyo Inside Dengyosha Machinery Works (72) Inventor Department Hiroshi Ota-ku, Tokyo Omorikita 1-chome fifth No. 1 stock company DMW CORPORATION in the F-term (reference) 3H020 AA01 AA03 AA07 BA02 BA11 BA18 CA07 DA01 DA08 DA21

Claims (8)

[Claims] An opening is provided in an upper portion of a pump casing or a suction elbow or a loose short pipe connected to the pump casing, and the opening is connected to a dry vacuum pump via a gas-liquid separating means so as to be connected to a pipe for filling water. A horizontal axis pump comprising: 2. The horizontal axis pump according to claim 1, wherein the opening communicates with the full-water detecting means, and the full-water detecting means communicates with the gas-liquid separating means via a vacuum shut-off valve. Separation means is connected to the dry vacuum pump by piping, and when full water is detected by the full water detection means, the vacuum shutoff valve is closed by control means and the dry vacuum pump is stopped. And horizontal axis pump. 3. The horizontal axis pump according to claim 1, wherein the opening communicates with the full-water detecting means, the full-water detecting means communicates with the gas-liquid separating means by a pipe, and the gas-liquid separating means is connected to a vacuum shut-off valve. The pipe is communicated with the dry vacuum pump through a pipe, and when the full water is detected by the full water detecting means, the vacuum shutoff valve is closed by the control means and the dry vacuum pump is stopped. And horizontal axis pump. 4. The horizontal-axis pump according to claim 1, wherein a plurality of horizontal-axis pumps are provided, and the openings provided in the plurality of horizontal-axis pumps respectively communicate with full-water detecting means. The full-water detecting means is connected to one of the gas-liquid separating means via a vacuum cutoff valve via a pipe, and the gas-liquid separating means is connected to the dry vacuum pump via a pipe. The control means operates the dry vacuum pump. And when any one of the vacuum shut-off valves is opened, and when the full-water detecting means to which the opened vacuum shut-off valve communicates detects full water,
This vacuum shutoff valve is closed and one of the other vacuum shutoff valves is closed.
One of the horizontal pumps is sequentially filled with water one by one, and when all the horizontal pumps are full, the vacuum shut-off valve that has been opened is closed and the dry vacuum pump is shut down. A horizontal axis pump characterized in that it is configured to perform 5. The horizontal-axis pump according to claim 1, wherein a plurality of horizontal-axis pumps are provided, and the openings provided in the plurality of horizontal-axis pumps are respectively connected to full-water detecting means. The full-water detecting means is connected to one of the dry vacuum pumps via a vacuum shutoff valve and the gas-liquid separation means via the vacuum shutoff valve, respectively, and the control means operates the dry vacuum pump and selects one of the vacuum shutoff valves. When the full state is detected by the fullness detecting means to which the opened vacuum shutoff valve communicates, the vacuum shutoff valve is closed, and one of the other vacuum shutoff valves is opened, and sequentially The plurality of horizontal axis pumps are filled one by one, and when all the horizontal axis pumps are full, the open vacuum shutoff valve is closed and the dry vacuum pump is shut down. Beside Shaft pump. 6. The vacuum tank according to claim 1, wherein said gas-liquid separation means has a larger cross-sectional area than a flow path cross-sectional area of an inflow-side pipe communicating therewith. A horizontal axis pump characterized by comprising: 7. The horizontal axis pump according to claim 1, wherein a filter for preventing passage of dust is provided between the dry vacuum pump and the gas-liquid separation means. Horizontal axis pump. 8. The horizontal axis pump according to claim 6, wherein a filter for preventing the passage of dust is provided at a position in the upper portion of the vacuum tank through which the gas from which the liquid is separated passes. Horizontal shaft pump.