Sealing liquid circulation device

Abstract

To provide a sealing liquid circulation device capable of improving maintainability while being capable of removing foreign matters contained in the sealing liquid.SOLUTION: A sealing liquid circulation device 1 is assembled with: a filter holding part 20 for exchangeably holding a filter 19 that captures foreign matters contained in a sealing liquid having been through a sealing liquid discharge passage 11 connected with a sealing liquid discharge port 2b of a water seal-type vacuum pump 2 in a sealing liquid passing state; an overflow tank 25 provided at a downstream side of the filter holding part and provided with an overflow port 27 for overflow of the sealing liquid and a return port 26 to which a sealing liquid return passage 12 for returning the sealing liquid is connected; a circulation pump 16 provided at a downstream side of the sealing liquid return passage and assembled in a sealing liquid feeding passage 13 for feeding a sealing liquid to the vacuum pump; and a sealing liquid replenishment passage 8 for replenishment of a sealing liquid circulated by the circulation pump into a circulation path 10.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a seal liquid circulation device connected to a water seal vacuum pump. [Background technology]

[0002] Water-sealed vacuum pumps have been known for some time to suck gases generated from materials (raw materials) in molding machines such as extrusion molding machines and various processing machines. In such vacuum pumps, the sealing liquid containing the gas is discharged as wastewater. For example, Patent Document 1 below discloses a water and air purification method for a water ring vacuum pump that sucks in gas containing dust discharged from a vent hole in a vented extruder. In this purification method, some of the impurities contained in the industrial water used by the pump are separated and settled in a separator shaped like a cylindrical section and a conical section below it, and the impurities contained in the water flow that reaches the bottom of the conical section, reverses, and rises are blocked by a filter located above the interior of the cylindrical section. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-73079 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the purification method described in Patent Document 1, it is necessary to stop the pump when cleaning the filter by supplying water into the separation device from a make-up water tank installed above the separation device, and further improvement is desired.

[0005] The present invention has been made in view of the above-mentioned circumstances, and has an object to provide a sealing liquid circulation device that is capable of removing foreign matter contained in the sealing liquid while improving maintainability. [Means for solving the problem]

[0006] In order to achieve the above object, the sealing liquid circulation device according to the present invention comprises a filter holder that holds a replaceable filter in a state where the sealing liquid passes through, the filter capturing foreign matter contained in the sealing liquid that has passed through a sealing liquid discharge path connected to a sealing liquid discharge port of a water-sealed vacuum pump; Passed through the filter without being captured The sealing liquid Foreign matter contained in of Together with the sealing liquid an overflow tank provided with an overflow port for overflow and a return port to which a sealing liquid return path for returning the sealing liquid is connected; a circulation pump provided downstream of the sealing liquid return path and incorporated in a sealing liquid supply path for supplying the sealing liquid to the vacuum pump; and a supply path for supplying the sealing liquid into the circulation path of the sealing liquid circulated by the circulation pump. The overflow tank is shaped to open upward below the filter holding portion, the overflow port is provided on the peripheral wall of the overflow tank, and the return port is provided below the overflow port. It is characterized by the presence of In order to achieve the above object, the sealing liquid circulation device according to the present invention comprises a filter holder that holds a replaceable filter in a state where the sealing liquid passes through, the filter capturing foreign matter contained in the sealing liquid that has passed through a sealing liquid discharge path connected to a sealing liquid discharge port of a water-sealed vacuum pump; an overflow tank that is provided downstream of the filter holder and that is provided with an overflow port through which the sealing liquid overflows and a return port to which a sealing liquid return path that returns the sealing liquid is connected; and a circulation tank that is provided downstream of the sealing liquid return path and that is incorporated in a sealing liquid supply path that supplies the sealing liquid to the vacuum pump. The heat exchanger is characterized in that it comprises a ring pump, a supply path for supplying sealing liquid into a circulation path of the sealing liquid circulated by the circulation pump, and a separation section in which the downstream end of the sealing liquid return path is connected to an upper end portion and in which foreign matter contained in the sealing liquid is caused to settle while swirling and can be discharged from a discharge port at the lower end, the separation section being provided in a heat exchange tank to which the upstream end of the sealing liquid supply path in which the circulation pump is incorporated is connected, and in the heat exchange tank, a cooling path for passing a cooling medium is provided in a spiral shape so as to surround the outer periphery of the separation section. [Effects of the Invention]

[0007] The sealing liquid circulation device according to the present invention is configured as described above, and therefore can improve maintainability while making it possible to remove foreign matter contained in the sealing liquid. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic system diagram showing an example of a sealing liquid circulation device according to an embodiment of the present invention and an example of a sealing liquid circulation system including the same. FIG. [Figure 2] 1A and 1B are schematic diagrams showing an example of an overflow tank provided in an enclosed liquid circulation device, where 1A is a schematic plan view and 1B is a schematic vertical cross-sectional view. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In some drawings, some of the detailed reference numerals used in other drawings are omitted. In FIG. 1, pipelines (piping) and the like that serve as paths through which liquid (sealing liquid) and the like pass are schematically shown by solid lines. In the following embodiment, directions such as the up-down direction will be described based on the state in which the sealing liquid circulation device according to this embodiment is installed.

[0010] 1 and 2 are diagrams schematically showing an example of a sealing liquid circulation device according to this embodiment. As shown in FIG. 1, the seal liquid circulation device 1 according to this embodiment is configured to circulate seal liquid through a water-sealed vacuum pump 2 via a circulation path 10. The vacuum pump 2 may be configured, for example, such that a sealing liquid (sealing water) is contained in a circular casing and an impeller is attached at an eccentric position relative to the casing. In this vacuum pump 2, a ring-shaped sealing water is formed by centrifugal force when the impeller is rotated, and suction, compression, and discharge are performed by changing the volume of the space surrounded by this sealing water and the blades. As the water-sealed vacuum pump 2, pumps with various known configurations can be used.

[0011] The connection target 3 to which the suction port of this vacuum pump 2 is connected may be a molding machine or processing machine that generates various gases, water vapor, etc. during a molding or processing process. The connection target 3 may be, for example, a synthetic resin molding machine such as an extruder or injection molding machine. For example, the suction side of the vacuum pump 2 may be connected to a vent hole of a vent-type extruder or injection molding machine or to the cylinder of an injection molding machine. In this case, the gas generated from the resin material being melted in the synthetic resin molding machine may be the object to be sucked by the vacuum pump 2. An appropriate gas-liquid separator may be provided downstream of the vacuum pump 2, and the gas sucked in by the vacuum pump 2 may be exhausted in this gas-liquid separator.

[0012] 1 and 2, the sealing liquid circulation device 1 includes a filter holder 20 that replaceably holds a filter 19 in a state where the sealing liquid passes through. The filter 19 traps foreign matter contained in the sealing liquid that has passed through the sealing liquid discharge path 11 connected to the sealing liquid discharge port 2b of the vacuum pump 2. With this configuration, the filter 19 held in the filter holder 20 can trap foreign matter such as oil contained in the sealing liquid discharged from the vacuum pump 2. Furthermore, the filter 19 can be replaced in a state where the sealing liquid discharged from the vacuum pump 2 passes through. This eliminates the need to stop the vacuum pump 2, the device 3 to which it is connected, such as an extruder, or the circulation pump 16 (described later), improving maintainability.

[0013] The sealing liquid circulation device 1 is provided with an overflow tank 25 that is provided downstream of this filter holding part 20 and that is provided with an overflow port 27 through which the sealing liquid overflows and a return port 26 to which the sealing liquid return path 12 that returns the sealing liquid is connected. With this configuration, foreign matter such as oil that has a smaller specific gravity than the sealing liquid and that passes through without being captured by the filter 19 can be discharged from the overflow port 27 of the overflow tank 25. In addition, because foreign matter such as oil is captured by the filter 19 upstream of the overflow port 27, the amount of foreign matter contained in the overflowing sealing liquid and the amount of overflowing sealing liquid can be reduced, thereby reducing the environmental load. The sealing liquid circulation device 1 is provided downstream of the sealing liquid return path 12 and includes a circulation pump 16 incorporated in the sealing liquid supply path 13 that supplies the sealing liquid to the vacuum pump 2. With this configuration, the sealing liquid can be circulated and reused. The sealing liquid circulation device 1 is provided with a supply path 8 for supplying sealing liquid to a circulation path 10 for the sealing liquid circulated by the circulation pump 16. With this configuration, it is possible to supply sealing liquid according to the amount of overflowed sealing liquid.

[0014] In this embodiment, as shown in FIG. 1 , the sealing liquid circulation device 1 includes a separation section 35 in which the downstream end of the sealing liquid return path 12 is connected to the upper end portion and which swirls and settles contaminants contained in the sealing liquid, allowing them to be discharged from a discharge port 39 at the lower end. With this configuration, contaminants such as silica and scale, which have a higher specific gravity than the sealing liquid and which pass through the filter 19 and overflow tank 25 without being removed, can be separated and discharged in the separation section 35. The filter 19, overflow tank 25, and separation section 35 effectively remove contaminants contained in the sealing liquid discharged from the vacuum pump 2. This effectively removes contaminants contained in the sealing liquid flowing toward the suction side of the circulation pump 16, thereby protecting the circulation pump 16. In this embodiment, the separation section 35 is provided in a heat exchange tank 30 to which the upstream end of the sealing liquid supply path 13, in which the circulation pump 16 is incorporated, is connected. Within the heat exchange tank 30, a cooling path 34, through which a cooling medium passes, is spirally provided so as to surround the outer periphery of the separation section 35. With this configuration, the sealing liquid can be indirectly cooled by the cooling path 34 in the heat exchange tank 30. Furthermore, the tank accommodating the separation unit 35 can function as the heat exchange tank 30, which makes it possible to make the tank more compact than a configuration in which these are provided separately. Furthermore, the sealing liquid that descends while swirling in the separation unit 35 and then ascends can be effectively cooled by the cooling path 34 on the outer periphery thereof.

[0015] That is, as shown in FIG. 1, in this embodiment, the circulation path 10 includes a sealing liquid discharge path 11, an overflow tank 25, a sealing liquid return path 12, a heat exchange tank 30 provided with a separation section 35, and a sealing liquid supply path 13. In this embodiment, a flow rate adjusting unit 9 is incorporated in the supply path 8 that supplies sealing liquid to the circulation path 10. With this configuration, the amount of sealing liquid supplied to the circulation path 10 via the supply path 8 can be adjusted by the flow rate adjusting unit 9. This makes it possible to adjust the amount of sealing liquid that overflows depending on the contaminated water level of the overflowing sealing liquid, for example. The supply path 8 is provided so as to branch off from a supply path 6 that is connected to a sealing liquid supply source 4, which will be described later. In the illustrated example, the downstream end of the supply path 8 is connected to an intermediate position of the sealing liquid return path 12, but it may be connected to an appropriate position within the circulation path 10. The flow rate adjusting unit 9 may be an appropriate flow rate adjusting valve such as a flow meter or a needle valve, or may be a manual adjusting valve that allows the amount of replenishment to be adjusted manually.

[0016] The sealing liquid discharge path 11 is provided so that its upstream end is connected to the sealing liquid discharge port 2b of the vacuum pump 2 and its downstream end is located upstream of the filter 19. In this embodiment, as shown in FIGS. 2(a) and 2(b), the filter holding part 20 is provided with a passage part 23 through which the sealing liquid passes and a mounting part 22 on the upper surface of which the filter 19 is mounted. The water discharge part 24 constituting the downstream end of the sealing liquid discharge path 11 is provided above the mounting part 22 so as to cause the sealing liquid to flow down onto the mounting part 22. With this configuration, foreign matter contained in the sealing liquid flowing down from the water discharge part 24 constituting the downstream end of the sealing liquid discharge path 11 can be captured by the filter 19 mounted on the mounting part 22 below it. Furthermore, since the filter 19 is placed on the placing portion 22 below the water discharge portion 24 of the sealing liquid discharge path 11, it can be replaced extremely easily compared to a configuration in which the filter is incorporated, for example, in an intermediate portion of the path or in an intermediate portion of the overflow tank 25 and must be replaced by sliding it, etc. Furthermore, the operator can easily recognize the degree of dirt on the filter 19.

[0017] In this embodiment, the filter holding part 20 is a lid member that covers the upper end opening of the overflow tank 25. With this configuration, the filter holding part 20 serving as a lid member can prevent foreign matter from entering the overflow tank 25, while still achieving a more compact configuration than a configuration in which the filter holding part 20 is provided at a separate position upstream of the overflow tank 25. This filter holding portion 20 is configured by providing a mounting portion 22 on a lid main body 21 provided so as to cover the upper end opening of the overflow tank 25. In the illustrated example, the lid main body 21 is substantially disk-shaped to match the shape of the substantially cylindrical overflow tank 25, but is not limited to this shape. In the illustrated example, the lid main body 21 is configured such that an upper end cover portion that hangs downwards is provided around the entire outer periphery of the outer periphery.

[0018] The mounting portion 22 is provided in a central portion of the lid body 21. The mounting portion 22 is recessed in a stepped shape from the upper surface of the lid body 21. The mounting portion 22 is provided to cover from below a through-hole provided in the central portion of the lid body 21, and a rising portion of its outer peripheral end may be joined to the underside of the lid body 21. The bottom of the mounting portion 22, where the filter 19 is placed, is shaped like a substantially horizontal plate in the illustrated example, but is not limited to this form. The mounting portion 22 may have an appropriate shape so that foreign matter contained in the sealing liquid flowing down from the water discharge portion 24, which will be described later, can be effectively captured by the filter 19. For example, the mounting portion 22 may be inclined downward as it moves away from the portion that receives the sealing liquid flowing down from the water discharge portion 24. As will be described later, when the water discharge port 24b of the water discharge unit 24 is provided above the approximate center of the mounting unit 22 in a plan view, the mounting unit 22 may be formed in a dish shape, an approximate cone shape, or the like that slopes downward from the center toward the radially outward direction. Also, approximately the entire lid body 21 may be the mounting unit 22.

[0019] The mounting portion 22 is provided with a large number of passing portions 23. In the illustrated example, the passing portions 23 are formed by punched holes in the mounting portion 22, which is formed in a punched metal shape, but the configuration is not limited to this. The passing portions 23 may be meshes of the mesh-shaped mounting portion 22, slit-shaped holes formed in the mounting portion 22, or may have various other configurations. The filter 19 replaceably mounted on the mounting portion 22 is in the form of a sheet and has a shape that covers substantially the entire mounting portion 22. The filter 19 may be a paper filter capable of capturing oil, or a nonwoven fabric filter made of various fibers. The method of replacing the filter 19 is not limited to a configuration in which a single filter 19 is removed from and replaced on the mounting portion 22. For example, a configuration in which a rolled filter 19 is supplied toward the mounting portion 22, and the dirty portion is wound up and replaced may be used. Various other configurations are also possible. The filter 19 and the passage portion 23 of the mounting portion 22 may be appropriately configured so that the sealing liquid flowing down from the water discharge portion 24 flows into the downstream overflow tank 25 without overflowing outside the mounting portion 22.

[0020] The water discharger 24 is fixed to the lid body 21 by a suitable fixing member such as a bracket. The water discharger 24 is provided with a connection port 24a to which the downstream end of the sealing liquid discharge path 11 is connected and a water discharge port 24b from which the sealing liquid is discharged. In the illustrated example, the water discharger 24 is provided so as to extend from a portion supported by a fixing member fixed to the lid body 21 on the side of the mounting portion 22 toward the center of the mounting portion 22 in a plan view. The water discharge port 24b is provided at the tip of the water discharger 24 in the extension direction so as to discharge the sealing liquid toward approximately the center of the mounting portion 22 in a plan view. The water discharge port 24b of the water discharger 24 is not limited to this configuration and may have various other configurations. For example, the water discharge port 24b may be configured to allow the sealing liquid to flow downward so as to be diffused over most of the filter 19. Furthermore, the water discharge port 24b is not limited to a configuration in which it opens downward but may be configured to open upward and spray in a fountain-like manner.

[0021] The overflow tank 25 has a cylindrical shape (approximately cylindrical in the illustrated example) with a bottom and a peripheral wall, and is open at the top. In the illustrated example, the inner diameter and height of the overflow tank 25 are approximately the same, but this configuration is not limited to this. The volume of the overflow tank 25 may be an appropriate volume depending on the flow rate of the sealing liquid flowing down from the water discharge portion 24, etc. The overflow port 27 of the overflow tank 25 is provided so as to open at the upper end portion of the peripheral wall. This overflow port 27 is provided so as to form a space between the liquid level (overflow level) of the sealing liquid in the overflow tank 25 and the mounting portion 22. In the illustrated example, the overflow port 27 is provided at a height of about ¾ from the bottom side of the overflow tank 25, but this position is not limited to this. An appropriate drainage path 28 may be connected to this overflow port 27. A level meter may be provided to detect an abnormal rise in the sealing liquid level in the overflow tank 25, and an abnormality signal may be output upon detection by this level meter. This can notify the operator that the sealing liquid level in the overflow tank 25 has risen abnormally due to an abnormality such as clogging of the sealing liquid return path 12 or the drainage path 28.

[0022] Return port 26 of overflow tank 25 is provided so as to open below overflow port 27. In this embodiment, return port 26 is provided so as to open at a position midway in the height direction (vertical direction) of the peripheral wall of overflow tank 25. With this configuration, foreign matter with a relatively large specific gravity can be allowed to settle (sediment) at the bottom of overflow tank 25, compared to a configuration in which return port 26 opens at the bottom of overflow tank 25. In the illustrated example, return port 26 is provided so as to be located approximately in the center of overflow tank 25 in the vertical direction, but the location is not limited to this. The upstream end of the sealing liquid return path 12 is connected to the return port 26 of the overflow tank 25. As shown in Figure 1, an example is shown in which a valve is provided in the middle of the sealing liquid return path 12 to allow or block the passage of the sealing liquid.

[0023] The heat exchange tank 30 is configured to store the sealing liquid in a filled state (full state) and is cylindrical with a bottom, peripheral walls, and a top. As shown in FIG. 1 , the heat exchange tank 30 is provided with a supply port 31 to which a sealing liquid supply path 6 is connected and a supply port 32 to which a sealing liquid feed path 13 is connected. The supply path 6 is connected to a sealing liquid supply source 4. The sealing liquid supply source 4 may be a water supply (industrial water supply, municipal water supply) that supplies water (clean water). A supply valve 6a is provided in the middle of the supply path 6. The supply valve 6a may be an electromagnetic valve or the like that is connected to a control unit that controls the sealing liquid circulation device 1 via a signal line or the like and is controlled to open and close. In the illustrated example, a filter 5 is provided upstream of the supply valve 6a. The supply port 32 is connected to the suction side of the circulation pump 16 and to the suction side sealing liquid supply path 14 that constitutes the upstream side of the sealing liquid supply path 13. In the illustrated example, the supply port 32 is provided so as to open at the lower end side of the peripheral wall portion, but the position is not limited to this.

[0024] The circulation pump 16 is provided with a casing that houses an impeller, an appropriate motor for rotating the impeller, etc. A discharge-side sealing liquid feed path 15 that constitutes the downstream side of the sealing liquid feed path 13 is connected to the discharge side of the circulation pump 16. The downstream end of the discharge-side sealing liquid feed path 15 is connected to the sealing liquid supply port 2a of the vacuum pump 2. A pressure gauge 17 that detects the discharge pressure of the circulation pump 16 is provided at an appropriate position on the discharge-side sealing liquid feed path 15. In the example shown in the figure, a valve that allows or blocks the passage of the sealing liquid is provided at a position along the discharge-side sealing liquid feed path 15. A level meter 33 is provided at an appropriate location (for example, on the top) of the heat exchange tank 30 to detect a drop in the sealing liquid level inside the heat exchange tank 30. This level meter 33 may be configured to output a replenishment signal or an abnormality signal when the sealing liquid level inside the heat exchange tank 30 drops from the full level to a predetermined level.

[0025] The cooling path 34 is provided in the heat exchange tank 30 so as to indirectly cool the sealing liquid circulating through the circulation path 10. The cooling path 34 is provided in a spiral shape from the lower end of a straight pipe portion that hangs downward from the top of the heat exchange tank 30 to the upper side so as to surround the outer periphery of a separation section 35 (described later). The upstream end of the cooling path 34 is connected to the cooling medium supply path 7. In the illustrated example, the cooling medium supply path 7 is provided by branching off from the supply path 6. That is, although the illustrated example shows an example in which the cooling medium supply source is the sealing liquid supply source 4, the present invention is not limited to this embodiment and other supply sources may be used. Furthermore, instead of water, a cooling tower or the like installed in a factory may be used. Furthermore, a supply source that supplies ethanol, ethylene glycol, or other cooling medium may be used.

[0026] A cooling valve 7a is provided in the cooling medium supply path 7. Like the supply valve 6a, this cooling valve 7a may be a solenoid valve or the like whose opening and closing is controlled by the control unit. The cooling valve 7a may be controlled to open and close by the control unit based on the temperature detected by a temperature sensor 18 that is provided in the heat exchange tank 30 or downstream thereof and detects the temperature of the sealing liquid. In other words, the sealing liquid may be cooled by controlling the opening and closing of the cooling valve 7a so that the temperature of the sealing liquid supplied to the vacuum pump 2 is equal to or lower than a predetermined temperature. In the illustrated example, the temperature sensor 18 is provided in the sealing liquid supply path 13 (suction-side sealing liquid supply path 14) between the heat exchange tank 30 and the circulation pump 16, but the location is not limited to this. The downstream end of this cooling path 34 may be led out of the heat exchange tank 30 from the top or the like and connected to an appropriate cooling medium discharge path.

[0027] The separation section 35 includes a cylindrical upper cylindrical portion and a generally inverted truncated cone cylindrical portion 38 that is connected to the lower side of the upper cylindrical portion and tapers in diameter toward the lower end. The cylindrical portion of the separation section 35 is provided with an inlet 36 that opens in the inner peripheral wall so that the sealing liquid is introduced in a generally tangential direction relative to the inner peripheral wall. The inlet 36 is connected to an appropriate connecting pipe that is tangential to the cylindrical portion and is connected to the downstream end of the sealing liquid return path 12. The separation section 35 includes an inner cylindrical portion 37 that is coaxial with the axial center of the cylindrical portion. The inner peripheral edge of the upper end of the cylindrical portion and the outer peripheral edge of the upper end of the inner cylindrical portion 37 are sealed by an annular lid, and the upper end of the inner cylindrical portion 37 is open upward. The inner cylindrical portion 37 may extend downward from the upper end of the cylindrical portion and may be provided over most of the cylindrical portion. A cylindrical discharge section is provided at the lower end of the separation section 35 so as to be continuous with the lower side of the generally inverted truncated cone cylindrical section 38. This cylindrical discharge section may be provided so as to penetrate the bottom of the heat exchange tank 30, and an appropriate drainage path 29 may be connected to a drain outlet 39 at the lower end. In the illustrated example, a valve is provided midway along the drainage path 29 to allow or block the passage of drained liquid.

[0028] In the separation section 35 configured as described above, the sealing liquid introduced through the inlet 36 moves downward while swirling along the inner circumferential wall of the cylindrical section, and at that time, foreign matter with a relatively large specific gravity settles toward the lower end. Moreover, the sealing liquid introduced into the separation section 35 moves downward while swirling, then rises, passes through the lower end opening of the inner cylindrical section 37, is discharged from the upper end opening, and moves into the heat exchange tank 30. The foreign matter that has settled on the lower end side of the separation section 35 can be discharged by opening the valve of the drainage path 29. In the illustrated example, the upper end of the separation section 35 is arranged to protrude upward from the outer periphery of the top part of the heat exchange tank 30, and an outer tube part is provided on the top part to surround the outer periphery of the upper end of the separation section 35, but this example is not limited to this. In the sealing liquid circulation device 1 configured as above, when circulating the sealing liquid through the vacuum pump 2, the supply valve 6a may be opened to supply the sealing liquid into the circulation path 10 including the heat exchange tank 30, and the circulation pump 16 may be operated to circulate the sealing liquid. Also, for example, the flow rate adjusting unit 9 of the supply path 8 may be adjusted as appropriate while checking the degree of contamination of the filter 19, thereby adjusting the amount of sealing liquid replenished, that is, the amount of sealing liquid to be overflowed.

[0029] In this embodiment, an example is shown in which the flow rate adjusting unit 9 is provided in the supply path 8, but such a flow rate adjusting unit 9 may not be provided. In this embodiment, an example is shown in which a separation section 35 is provided inside the heat exchange tank 30, but the separation section 35 may also be provided outside the heat exchange tank 30, or even a configuration in which such a separation section 35 is not provided. In this embodiment, an example is shown in which the cooling section that cools the sealing liquid circulating through the circulation path 10 is the cooling path 34 provided in the heat exchange tank 30, but the present invention is not limited to this, and an air-cooled cooler may be used, and further, a direct cooling type may be used instead of the indirect cooling configuration. For example, a configuration may be used in which the sealing liquid is directly cooled by the sealing liquid supplied or replenished through the supply path 6 or the replenishment path 8.

[0030] In this embodiment, an example is shown in which the filter holding portion 16 is used as a lid member for the overflow tank 25, but this configuration is not limited to this. The filter holding portion 16 may be provided at a separate position above the upper end opening of the overflow tank 25, or may be provided so as to span the overflow tank 25. In this case, an opening may be provided on the side circumferential surface of the overflow tank 25 to allow the filter 19 (or the mounting portion 22 on which the filter 19 is mounted) to be freely inserted and removed. The filter holding portion 16, which holds the filter 19 in a replaceable state while the sealing liquid passes through it, may have various other configurations. The specific configurations of the various components provided in the sealing liquid circulation device 1 according to this embodiment described above are not limited to the configurations described above, and various other modifications are possible. [Explanation of symbols]

[0031] 1 Sealing liquid circulation device 8 Supply route 9 Flow rate adjustment section 10 Circulation Route 11 Sealing liquid discharge path 12 Sealing liquid return path 13 Sealing liquid supply path 16 Circulation pump 19 filters 20 Filter holder 22 Placement section 23 Passage section 24 Water outlet (downstream end of sealing liquid discharge path) 25 Overflow tank 26 Return Port 27 Overflow port 30 Heat exchange tank 34 Cooling path 35 Separation part 39 Outlet 2. Vacuum pump 2b Sealing liquid outlet

Claims

1. a filter holder that holds a replaceable filter in a state where the sealing liquid passes through, the filter capturing foreign matter contained in the sealing liquid that has passed through a sealing liquid discharge path connected to a sealing liquid discharge port of a water-sealed vacuum pump; an overflow tank that is provided downstream of the filter holder and that is provided with an overflow port through which foreign matter contained in the sealing liquid that has passed through without being captured by the filter overflows together with the sealing liquid and a return port to which a sealing liquid return path for returning the sealing liquid is connected; a circulation pump that is provided downstream of the sealing liquid return path and that is incorporated in a sealing liquid supply path for supplying the sealing liquid to the vacuum pump; and a supply path for supplying the sealing liquid into the circulation path of the sealing liquid circulated by the circulation pump, the overflow tank has a shape that opens upward below the filter holding portion, the overflow port is provided in a peripheral wall portion of the overflow tank, and the return port is provided below the overflow port.

2. In claim 1, a downstream end of the sealing liquid return path connected to an upper end portion, and a separation section configured to cause foreign matter contained in the sealing liquid to swirl and settle, and to discharge the foreign matter from a discharge port at a lower end.

3. A water-sealed vacuum pump comprising: a filter holder that replaceably holds a filter that captures foreign matter contained in the sealing liquid that has passed through a sealing liquid discharge path connected to the sealing liquid discharge port of the water-sealed vacuum pump while the filter is passing through; an overflow tank that is provided downstream of the filter holder and has an overflow port through which the sealing liquid overflows and a return port to which a sealing liquid return path that returns the sealing liquid is connected; a circulation pump that is provided downstream of the sealing liquid return path and incorporated in a sealing liquid supply path that supplies sealing liquid to the vacuum pump; a supply path that supplies sealing liquid to the sealing liquid circulated by the circulation pump; and a separation section whose downstream end of the sealing liquid return path is connected to an upper end portion and which causes foreign matter contained in the sealing liquid to settle while swirling so that it can be discharged from a discharge port at the lower end, a sealing liquid circulation device characterized in that the separation unit is provided in a heat exchange tank to which an upstream end of a sealing liquid supply path incorporating the circulation pump is connected, and a cooling path through which a cooling medium passes is provided in a spiral shape in the heat exchange tank so as to surround an outer periphery of the separation unit.

4. In any one of claims 1 to 3, the filter holding portion is provided with a passage portion through which the sealing liquid passes and includes a mounting portion on an upper surface of which the filter is mounted, The sealing liquid circulation device is characterized in that the downstream end of the sealing liquid discharge path is provided above the mounting part so as to allow the sealing liquid to flow down to the mounting part.

5. In claim 4, The sealing liquid circulation device is characterized in that the filter holding portion is a lid member that covers an upper end opening of the overflow tank.

6. In any one of claims 1 to 5, A sealing liquid circulation device characterized in that a flow rate adjusting unit is incorporated in the supply path.

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