Liquid seal pump

Abstract

To provide a liquid seal pump which can inhibit deterioration of a mechanical seal and prevent leakage of a liquid from the mechanical seal.SOLUTION: A liquid seal pump (10) includes: a first housing part (16) in which an impeller (12) and a sealing liquid are housed; a second housing part (17) in which a mechanical seal (24) sealing the periphery of a rotary shaft (13) of the impeller is disposed; a motor (15) which rotates the impeller; a suction port (19) which communicates with the first housing part; a discharge port (20) which communicates with the first housing part and discharges the sealing liquid; and a circulation water supply port (18) which communicates with the first housing part and to which circulation water used as the sealing liquid is supplied. The liquid seal pump (10) directly supplies make-up water to the second housing part without passing through the first housing part and thereby inhibits the sealing liquid containing foreign objects in the first housing part from penetrating into the mechanical seal.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a liquid ring pump. [Background technology]

[0002] There is known a liquid ring pump that has an impeller in a casing, and generates suction force by filling the casing with sealing liquid and rotating the impeller to suck in and discharge the fluid (for example, Patent Documents 1 and 2). This type of liquid ring pump is used for various purposes, and is applied, for example, as a pump that generates suction force to suck and hold a workpiece on a holding table in a processing device.

[0003] As an example of the configuration of a liquid ring pump, a casing is connected to a circulating fluid supply port that supplies the circulating fluid that serves as the sealing fluid, a make-up fluid supply port that supplies make-up fluid, a suction port, a discharge port, etc., and by moving the sealing fluid inside the casing with the rotation of the impeller, fluid (air, water, etc.) is sucked in through the suction port, and the sealing liquid containing the sucked fluid is discharged from the discharge port. The circulating fluid gradually decreases as it circulates between the liquid ring pump and the circulating water supply source, and the loss of circulating fluid is replenished by the supply of make-up fluid.

[0004] In many liquid ring pumps, the rotating shaft of the impeller protrudes outside the casing and is connected to the motor. Because the rotating shaft passes through a through hole formed in the casing, a configuration is required that allows the rotating shaft to rotate while preventing fluids such as sealing liquid in the casing from leaking (leaking) to the outside through the through hole. Mechanical seals are known to meet such requirements (for example, Patent Document 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2023-053432 A [Patent Document 2] Japanese Patent Application Publication No. 5-018383 Summary of the Invention [Problem to be solved by the invention]

[0006] A mechanical seal comprises a fixed ring attached to a casing and a rotating ring attached to a rotating shaft, and provides sealing when the rotating shaft rotates by forming a liquid film between the sliding surfaces of the fixed ring and the rotating ring, which are in slidable contact with each other. Therefore, the positional relationship between the fixed ring and the rotating ring needs to be precisely controlled, and if the gap and surface accuracy of the sliding surfaces do not satisfy the appropriate conditions, the formation of the liquid film is hindered and sealing performance is impaired.

[0007] When a liquid ring pump is connected to a processing device that generates foreign matter such as machining chips during processing, the fluid containing the foreign matter is sucked in through the suction port, and the sealing liquid in the casing becomes contaminated with the foreign matter. When the sealing liquid containing the foreign matter penetrates into the mechanical seal, the foreign matter prevents the formation of an appropriate liquid film, and cracks occur on the sliding surface of the mechanical seal due to friction and heat, leading to the problem of liquid leakage from the liquid ring pump.

[0008] The present invention has been made in consideration of the above-mentioned points, and has an object to provide a liquid ring pump that can suppress deterioration of the mechanical seal and prevent liquid leakage from the mechanical seal. [Means for solving the problem]

[0009] A liquid ring pump according to one embodiment of the present invention comprises a first housing section in which an impeller and a sealing liquid are housed, a second housing section in which a mechanical seal is disposed to seal around the rotation shaft of the impeller, a motor for rotating the impeller, a suction port communicating with the first housing section, a discharge port communicating with the first housing section and for discharging the sealing liquid, and a circulating water supply port communicating with the first housing section and for supplying circulating water used as the sealing liquid. By supplying makeup water directly to the second housing section without passing through the first housing section, the sealing liquid containing foreign matter in the first housing section is prevented from penetrating the mechanical seal.

[0010] The replenishment liquid preferably flows from the second container to the first container. Effect of the Invention

[0011] According to the liquid ring pump of the present invention, makeup water is supplied directly to the second housing section which houses the mechanical seal, and the sealing liquid containing foreign matter in the first housing section is not allowed to penetrate into the mechanical seal, thereby suppressing deterioration of the mechanical seal and preventing liquid leakage from the mechanical seal. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a perspective view of a liquid ring pump according to an embodiment. [Diagram 2] 1 is a cross-sectional view showing an internal structure of a liquid ring pump according to an embodiment. [Diagram 3] 2 is an enlarged cross-sectional view of a portion of the internal structure of a liquid ring pump. FIG. [Figure 4] FIG. 2 is a cross-sectional view showing the internal structure of a liquid ring pump of a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, a liquid ring pump 10 according to this embodiment will be described with reference to the accompanying drawings. Fig. 1 shows the external structure of the liquid ring pump 10, and Fig. 2 shows the internal structure of the liquid ring pump 10. The liquid ring pump 10 of this embodiment is used as a pump that generates suction force for sucking and holding a workpiece on a holding table in a processing device. However, the use of the liquid ring pump to which the present invention is applied is not limited to this.

[0014] The liquid ring pump 10 includes an impeller 12 in a casing 11, and the impeller 12 is supported rotatably around a rotary shaft 13. In the liquid ring pump 10, the direction in which the rotary shaft 13 extends is defined as the axial direction. In the drawing, the axial direction is shown as the X-axis direction, with the Xa direction being the axial tip side and the Xb direction being the axial rear end side. The direction perpendicular to the center line of the rotary shaft 13 is defined as the radial direction.

[0015] A motor unit 14 is connected to the rear end side of the casing 11. The rotating shaft 13 protrudes from the casing 11 and is connected to a motor 15 built into the motor unit 14. The rotating shaft 13 is rotated by the driving force of the motor 15, and the impeller 12 rotates integrally with the rotating shaft 13.

[0016] The impeller 12 includes a shaft portion 121 having a solid structure through which the rotating shaft 13 is inserted at the center, and a plurality of blades 122 protruding radially outward from the outer circumferential surface of the shaft portion 121. The shaft portion 121 is fixed to the rotating shaft 13. The plurality of blades 122 are arranged at predetermined intervals in the circumferential direction of the shaft portion 121.

[0017] 2, a first housing portion 16 and a second housing portion 17 are formed inside the casing 11 and arranged side by side in the axial direction. The first housing portion 16 is located at the leading end side in the axial direction, and the second housing portion 17 is located at the rear end side in the axial direction. The first housing portion 16 forms a space that is wider in the radial direction than the second housing portion 17.

[0018] The first housing section 16 is formed with a cylindrical inner circumferential surface 161 surrounding the outer edge of the impeller 12, a tip inner surface 162 located on the tip side in the axial direction, and a bottom surface 163 located on the rear end side in the axial direction. In the radial direction of the liquid ring pump 10, the center of the impeller 12 (shaft portion 121 and rotating shaft 13) is disposed eccentrically with respect to the center of the first housing section 16 (inner circumferential surface 161). The bottom surface 163 is a surface approximately perpendicular to the axial direction, and the central portion of the bottom surface 163 is a circular opening communicating with the second housing section 17.

[0019] The casing 11 has a circulating water supply port 18, a suction port 19, and a discharge port 20 as portions communicating with the first storage section 16 from the outside. The circulating water supply port 18, the suction port 19, and the discharge port 20 each open to the inner surface 162 at the tip end of the first storage section 16. A circulating water supply source 21 is connected to the circulating water supply port 18. A pipe extending from a processing device (not shown) to be sucked is connected to the suction port 19, and the fluid on the processing device side can be sucked from the suction port 19. The discharge port 20 is connected to a fluid processing section (not shown) that processes the fluid discharged from the liquid ring pump 10. The fluid processing section includes a filter that removes foreign matter, a gas-liquid separator that separates the fluid into a gas component and a liquid component, a waste liquid section that wastes a part of the fluid, and the like.

[0020] Circulating water is delivered from the circulating water supply source 21. The circulating water supply port 18 opens on the inner tip surface 162 of the first housing portion 16 near the tip of the rotating shaft 13, which is the center of rotation of the impeller 12. The circulating water supplied from the circulating water supply source 21 enters the first housing portion 16 from the circulating water supply port 18. The circulating water that has entered the first housing portion 16 is used as a sealing liquid in the liquid ring pump 10, and as the impeller 12 rotates, the sealing liquid moves from the center side to the outside in the radial direction within the first housing portion 16.

[0021] In the liquid ring pump 10, the rotation of the impeller 12 moves the sealing liquid in the first housing 16 in the radial direction, and along with this movement of the sealing liquid, the fluid is sucked into the first housing 16 from the suction port 19 and discharged from the discharge port 20. The fluid sucked in from the suction port 19 is, for example, gas or liquid mixed with foreign matter (contamination) such as processing chips generated in the processing device that is the object of suction. The fluid discharged from the discharge port 20 is a mixture of the fluid sucked in from the suction port 19 and the sealing liquid that has moved inside the first housing 16. The foreign matter is removed from the fluid discharged from the discharge port 20, and the fluid is separated into gas and liquid by a gas-liquid separator, and a part of the separated liquid is sent to the circulating water supply source 21 and is again supplied to the liquid ring pump 10 as circulating water.

[0022] The casing 11 shown in FIG. 1 includes a removable cover member 111 at the tip side of the first storage section 16, and the circulating water supply port 18, the suction port 19, and the discharge port 20 are formed in the cover member 111, but is not limited to this configuration. The number of parts constituting the casing 11 and the location at which the parts are combined when the casing 11 is composed of multiple parts can be appropriately selected. However, it is preferable that the parts of the casing 11 other than the cover member 111, particularly the first storage section 16 and the second storage section 17, are integrally constituted as much as possible with common parts. This ensures the rigidity of the casing 11 and improves the relative positional accuracy of the first storage section 16 and the second storage section 17, making it easier to move the fluid inside the casing 11 as designed.

[0023] Inside the second housing section 17, there are formed an inner peripheral surface 171 having a truncated cone shape centered on the center line of the rotating shaft 13, and an annular support surface 172 and a rear end surface 173 located on the rear end side of the inner peripheral surface 171. The inner peripheral surface 171 is a surface whose inner diameter decreases from the tip side to the rear end side in the axial direction. The tip side of the inner peripheral surface 171 in the axial direction is connected to the first housing section 16 (an opening in the center part of the bottom surface 163). The annular support surface 172 is a cylindrical surface centered on the rotating shaft 13. The rear end surface 173 is a surface that is approximately perpendicular to the axial direction, and the center part of the rear end surface 173 is connected to a through hole 221 described later.

[0024] An annular rear end flange 22 that surrounds the rotating shaft 13 is formed on the axial rear end side of the casing 11. The surface on the axial tip side of the rear end flange 22 constitutes the rear end surface 173 of the second housing portion 17. A through hole 221 that penetrates in the axial direction is formed on the inner peripheral portion of the rear end flange 22. The through hole 221 is a cylindrical hole that surrounds the rotating shaft 13. There is a predetermined radial gap between the outer peripheral surface of the rotating shaft 13 and the through hole 221, and the rotating shaft 13 passes through the through hole 221 without coming into contact with the rear end flange 22.

[0025] The impeller 12 is accommodated in the first accommodating section 16. The impeller 12 is disposed near a bottom surface 163 of the first accommodating section 16 in the axial direction, and the rear end surface 123 of the impeller 12 and the bottom surface 163 face each other with a predetermined gap (clearance) therebetween in the axial direction. A communication flow passage 23 that communicates the first accommodating section 16 and the second accommodating section 17 with the impeller 12 accommodated in the first accommodating section 16 is formed by the gap between the rear end surface 123 and the bottom surface 163.

[0026] A mechanical seal 24 is provided as a structure for preventing the fluid in the casing 11 from leaking to the outside through the through hole 221 when the rotating shaft 13 is inserted into the through hole 221. Fig. 3 shows an enlarged view of the vicinity of the mechanical seal 24.

[0027] A fixed ring 25 and a rotating ring 26 constituting the mechanical seal 24 are disposed within the second housing portion 17. Both the fixed ring 25 and the rotating ring 26 are annular members surrounding the rotating shaft 13 and are made of ceramic, carbon, or the like, which have excellent heat resistance and durability. The fixed ring 25 is fixed to the casing 11, and the rotating ring 26 is fixed to the rotating shaft 13. When the rotating shaft 13 rotates, relative rotation occurs between the rotating ring 26, which rotates together with the rotating shaft 13, and the fixed ring 25, which is fixed to the casing 11 and does not rotate.

[0028] The cylindrical outer peripheral surface of the fixed ring 25 is supported by annular support surface 172 of the second housing portion 17. The rear end surface of the fixed ring 25 is supported by a rear end surface 173 of the second housing portion 17. The position of the fixed ring 25 relative to the casing 11 is determined by these support parts, and the fixed ring 25 is fixed to the casing 11 at that position. A sealing member (O-ring) 27 is disposed between the annular support surface 172 and the outer peripheral surface of the fixed ring 25, and the sealing member 27 seals the gap between the casing 11 and the fixed ring 25.

[0029] The inner peripheral surface 251 of the fixed ring 25 is a cylindrical surface surrounding the rotating shaft 13. If the inner peripheral surface 251 comes into strong contact with the rotating shaft 13, smooth rotation of the rotating shaft 13 will be hindered, so a predetermined clearance is formed between the inner peripheral surface 251 and the outer peripheral surface of the rotating shaft 13. This clearance between the inner peripheral surface 251 and the outer peripheral surface of the rotating shaft 13 is smaller than the gap between the outer peripheral surface of the rotating shaft 13 and the through hole 221.

[0030] An inner peripheral surface 261 of the rotary ring 26 is a cylindrical surface surrounding the rotary shaft 13. A sealing member (O-ring) 28 is disposed between the inner peripheral surface 261 and the outer peripheral surface of the rotary shaft 13, and the sealing member 28 seals the space between the rotary shaft 13 and the rotary ring 26.

[0031] A sliding surface 252 is formed on the axial tip side of the fixed ring 25. A sliding surface 262 is formed on the axial rear end side of the rotating ring 26. Both the sliding surface 252 and the sliding surface 262 are annular surfaces perpendicular to the axial direction and face each other.

[0032] A biasing member 29 is inserted between the impeller 12 and the rotary ring 26. The biasing member 29 is a compression coil spring, with an end portion on the axial tip side of the biasing member 29 abutting against the rear end face 123 and an end portion on the axial rear side of the biasing member 29 abutting against the rotary ring 26. The biasing member 29 biases in a direction to increase the axial distance between the impeller 12 and the rotary ring 26. In other words, the biasing member 29 biases the impeller 12 toward the axial tip side (to the right in Figures 2 and 3), and biases the rotary ring 26 toward the axial rear end side (to the left in Figures 2 and 3).

[0033] A shaft abutment portion (not shown) that restricts the rotary shaft 13 from moving toward the tip side is formed inside the casing 11, and the impeller 12 and the rotary shaft 13 that receive the biasing force of the biasing member 29 are held at a fixed position in the axial direction. The rotary ring 26 is pressed toward the rear end side by the biasing force of the biasing member 29, and a force is applied that presses the sliding surface 262 of the rotary ring 26 against the sliding surface 252 of the fixed ring 25.

[0034] When the rotating shaft 13 is at a stop in rotation, the rotating ring 26 is pressed against the fixed ring 25 by the biasing force of the biasing member 29, and the sliding surface 252 and the sliding surface 262 come into surface contact to seal the space between the rotating ring 26 and the fixed ring 25. The space between the casing 11 and the fixed ring 25 is sealed by the sealing member 27, the space between the rotating shaft 13 and the rotating ring 26 is sealed by the sealing member 28, and the space between the fixed ring 25 and the rotating ring 26 is further sealed by the surface contact between the sliding surface 252 and the sliding surface 262. Therefore, in the second housing portion 17, all the members between the casing 11 and the rotating shaft 13 are sealed.

[0035] When the rotating shaft 13 is rotating, the rotating ring 26 rotates together with the rotating shaft 13. At this time, the rotating ring 26 rotates while being slightly eccentric in the radial direction and tilted in the axial direction with respect to the fixed ring 25, and a very small gap is generated between the sliding surface 252 and the sliding surface 262. The liquid in the casing 11 penetrates into the gap between the sliding surface 252 and the sliding surface 262, forming a liquid film. The liquid film formed between the sliding surface 252 and the sliding surface 262 tends to be thinner on the inner diameter side closer to the rotating shaft 13 than on the outer diameter side farther from the rotating shaft 13, and the thin liquid film portion near the rotating shaft 13 is vaporized and evaporated by heat generated with the rotation of the rotating shaft 13 (relative rotation of the fixed ring 25 and the rotating ring 26). The evaporated steam passes through a clearance portion provided between the inner peripheral surface 251 of the fixed ring 25 and the outer peripheral surface of the rotating shaft 13 and escapes to the through hole 221 communicating with the atmosphere.

[0036] In addition, when the rotating shaft 13 rotates and the rotating ring 26 becomes eccentric or tilted, the sealing member 28 that seals the inner surface 261 of the rotating ring 26 prevents the liquid in the casing 11 from passing through the inside of the rotating ring 26 to the through hole 221.

[0037] In this way, the mechanical seal 24 functions to prevent the liquid inside the casing 11 from leaking out through the through hole 221 to the outside, whether the rotating shaft 13 is stationary or rotating.

[0038] Incidentally, gas or liquid containing foreign matter is sucked into the inside of the casing 11 through the suction port 19. If the sealing liquid containing foreign matter reaches the second storage section 17 and infiltrates into the mechanical seal 24, the sealing performance of the mechanical seal 24 may be impaired, leading to liquid leakage from the liquid ring pump 10. In detail, if foreign matter contained in the sealing liquid adheres to the rotating ring 26, the clearance between the sliding surface 252 and the sliding surface 262 becomes unbalanced, making it difficult for the sealing liquid to enter between the sliding surface 252 and the sliding surface 262, and the liquid film is not formed normally. This causes the liquid film around the rotating shaft 13 to become thinner, and the heat generated with the rotation of the rotating shaft 13 increases, causing roughness due to wear and cracks due to heat on the sliding surfaces 252 and 262 of the mechanical seal 24. As a result, the sealing performance is impaired, causing liquid leakage.

[0039] 4 shows a liquid ring pump 40 of a comparative example in which such a problem occurs. The liquid ring pump 40 has a connection flow path 41 that connects the first storage section 16 and the second storage section 17. The connection flow path 41 is a flow path that connects an opening formed in the bottom surface 163 of the first storage section 16 and an opening formed in the inner peripheral surface 171 of the second storage section 17. There is no flow path that directly connects the outside of the casing 11 to the second storage section 17, and the liquid that flows in and out of the second storage section 17 is structured to always pass through the first storage section 16.

[0040] A makeup water supply port 42 is provided in the middle of the flow path connecting the circulating water supply source 21 and the circulating water supply port 18. Make-up water is supplied from the makeup water supply source 43 to the makeup water supply port 42, and the makeup water merges with the circulating water supplied from the circulating water supply source 21 and enters the first storage unit 16 from the circulating water supply port 18.

[0041] The circulating water supplied from the circulating water supply source 21 is used as a sealing liquid in the liquid ring pump 40 and gradually decreases in volume as it circulates, and the temperature of the circulating water increases as it absorbs heat from the moving parts of the liquid ring pump 40. By replenishing makeup water from the makeup water supply source 43, the amount of sealing liquid can be maintained and the temperature of the sealing liquid can be lowered.

[0042] The circulating water supplied from the circulating water supply source 21 and the makeup water supplied from the makeup water supply source 43 flow through the first housing portion 16 as sealing liquid mixed with foreign matter sucked from the suction port 19. A part of the sealing liquid in the first housing portion 16 flows through the connecting flow path 41 to the second housing portion 17, and the second housing portion 17 is filled with the sealing liquid. Then, when the rotating shaft 13 rotates, the sealing liquid in the second housing portion 17 penetrates between the sliding surface 252 of the fixed ring 25 and the sliding surface 262 of the rotating ring 26 to form a liquid film. This sealing liquid contains foreign matter, and the adhesion of the foreign matter causes roughness due to wear and cracks due to heat to occur on the sliding surfaces 252 and 262 of the mechanical seal 24 as described above, thereby impairing the sealing performance.

[0043] Furthermore, the sealing liquid in the second storage portion 17 is returned to the first storage portion 16 through the communicating passage 23, but foreign matter contained in the sealing liquid has difficulty passing through the narrow communicating passage 23, and the foreign matter tends to remain and accumulate in the second storage portion 17. If foreign matter accumulates in the second storage portion 17, the foreign matter becomes even more likely to adhere to the mechanical seal 24, increasing the risk of impairing the sealing performance.

[0044] In this manner, in the liquid ring pump 40 having a structure in which sealing liquid containing foreign matter is caused to flow from the first storage section 16 to the second storage section 17 to form a liquid film, there is a problem in that damage to the mechanical seal 24 can easily occur, leading to liquid leakage from the through hole 221.

[0045] As a result of research and development by the applicant, the applicant has come to the idea that by supplying only make-up liquid that does not contain foreign matter to the second storage portion 17, it is possible to prevent sealing liquid containing foreign matter from entering the second storage portion 17, thereby solving the above problem and maintaining the sealing performance of the mechanical seal 24. The configuration of the liquid ring pump 10 of this embodiment that realizes this technical idea will be described below.

[0046] As shown in Figures 1 to 3, the casing 11 of the liquid ring pump 10 is provided with a make-up water supply port 30 that allows make-up water supplied from a make-up water supply source 31 to flow directly into the second storage section 17 without passing through the first storage section 16. The make-up water supplied from the make-up water supply source 31 is a liquid (e.g., pure water) that does not contain foreign matter. The make-up water supply port 30 is configured as a pipeline extending in the radial direction of the casing 11, with an end on the inner diameter side opening to an inner circumferential surface 171 of the second storage section 17 and an end on the outer diameter side opening to the outer circumferential surface of the casing 11. A water supply pipeline extending from the make-up water supply source 31 is connected to the end on the outer diameter side of the make-up water supply port 30.

[0047] Make-up water delivered from the make-up water supply source 31 passes through the make-up water supply port 30 and enters the interior of the second storage unit 17. The make-up water fills the interior of the second storage unit 17 and contributes to the formation of a liquid film in the mechanical seal 24. Because the make-up water that forms the liquid film does not contain foreign matter, there is no deterioration in the sealing performance of the mechanical seal 24 due to the adhesion of foreign matter, etc., and excellent sealing performance can be maintained by continuously supplying make-up water from the make-up water supply source 31 to the second storage unit 17.

[0048] When makeup water is supplied from the makeup water supply source 31 to the second storage section 17 via the makeup water supply port 30, the makeup water filled in the second storage section 17 flows through the communication flow path 23 into the first storage section 16. Then, the makeup water that has entered the first storage section 16 is discharged from the discharge port 20 together with the sealing liquid (such as the circulating water supplied from the circulating water supply port 18) that has moved within the first storage section 16. In other words, the makeup water supplied from the makeup water supply source 31 flows in the order of the makeup water supply port 30, the second storage section 17, the communication flow path 23, the first storage section 16, and the discharge port 20, and plays a role in forming a seal of the mechanical seal 24, replenishing the amount of sealing liquid, cooling heat-generating parts in the liquid ring pump 10 (mainly around the rotating shaft 13), etc.

[0049] When the impeller 12 is rotating, a flow that discharges the sealing liquid from the discharge port 20 is dominant in the first storage section 16. In addition, between the first storage section 16 and the second storage section 17, a flow is formed in which the makeup water filled in the second storage section 17 flows through the communication flow path 23 to the first storage section 16 as the impeller 12 rotates. Therefore, the inside of the second storage section 17 can be filled only with makeup water that does not contain foreign matter, without generating a flow in which the sealing liquid in the first storage section 16 flows into the second storage section 17 through the communication flow path 23.

[0050] As described above, in the liquid ring pump 10 of this embodiment, makeup water is supplied directly to the second storage section 17 without passing through the first storage section 16, thereby making it possible to prevent the sealing liquid in the first storage section 16 containing foreign matter sucked in from the suction port 19 from penetrating into the mechanical seal 24. Therefore, the foreign matter contained in the sealing liquid does not adhere to the mechanical seal 24, and the foreign matter does not accumulate in the second storage section 17. As a result, in the liquid ring pump 10, deterioration of the mechanical seal 24 is suppressed, and liquid leakage from the mechanical seal 24 can be prevented.

[0051] Furthermore, by supplying makeup water to the second housing portion 17 housing the mechanical seal 24, the periphery of the mechanical seal 24 can be efficiently cooled by the makeup water.

[0052] 2 and 3, the position where the makeup water supply port 30 opens into the inner circumferential surface 171 of the second storage portion 17 is a position facing the outer circumferential surface of the rotating ring 26. In other words, the makeup water supply port 30 is formed near the position closest to the mechanical seal 24 within the second storage portion 17. This configuration makes it easier to supply makeup water to the mechanical seal 24, and also enhances the effect of cooling heat generated near the mechanical seal 24 by the makeup water.

[0053] However, the position of the makeup water supply port is not limited to that in the illustrated embodiment. Since the liquid ring pump 10 rotates the impeller 12 and the rotating shaft 13 with the second housing portion 17 filled with makeup water, even if makeup water is introduced into the second housing portion 17 from a position away from the mechanical seal 24, a liquid film of makeup water can be formed on the mechanical seal 24.

[0054] The above-mentioned effects of the liquid ring pump 10 can be obtained by setting the makeup water supply position, so there is little modification to the existing liquid ring pump, and the comparative example can be realized simply and inexpensively. For example, in comparison with the liquid ring pump 40, which is the comparative example, the effect is achieved by changing the connection flow path 41 in the casing 11 to the makeup water supply port 30, so the structure other than the casing 11 can be reused.

[0055] The liquid ring pump 10 in the above embodiment has a structure (closed impeller) in which the entire outside of the impeller 12 is covered by the inner surface of the first housing section 16, but the liquid ring pump of the present invention may have a structure (open impeller) in which at least a part of the impeller is exposed and not covered by the first housing section. As long as the requirement of directly supplying makeup water to the second housing section that houses the mechanical seal is met, the structure of the first housing section may be different from that of the above embodiment.

[0056] The embodiments of the present invention are not limited to the above-mentioned embodiments and modifications, and may be modified, substituted, or altered in various ways without departing from the spirit of the technical idea of ​​the present invention. Furthermore, if the technical idea of ​​the present invention can be realized in a different way due to technological progress or a derived technology, the present invention may be implemented using that method. Therefore, the claims cover all embodiments that may be included within the scope of the technical idea of ​​the present invention. [Industrial Applicability]

[0057] As described above, the liquid ring pump of the present invention can suppress deterioration of the mechanical seal and prevent liquid leakage from the mechanical seal by directly supplying makeup water to the second housing that houses the mechanical seal. In particular, in a liquid ring pump that transfers fluid between a processing device that is prone to generating foreign matter such as machining chips, foreign matter is likely to enter the first housing that houses the impeller and the sealing liquid, so the liquid ring pump of the present invention that can protect the mechanical seal from the intrusion of foreign matter is particularly useful. [Explanation of symbols]

[0058] 10: Liquid ring pump 11: Casing 12: Impeller 121: Shaft 122: Feather 123: Rear end surface 13: Rotation axis 14: Motor unit 15: Motor 16: First storage section 161: Inner surface 162: Tip inner surface 163: Bottom 17: Second storage section 171: Inner surface 172: Annular support surface 173: Rear end surface 18: Circulating water supply port 19: Suction port 20: Outlet 21: Circulating water supply source 22: Rear flange 221: Through hole 23: Connecting flow path 24: Mechanical seal 25: Fixed ring 251: Inner surface 252: Sliding surface 26: Rotating Ring 261: Inner surface 262: Sliding surface 27: Sealing member 28: Sealing member 29: Pressurizing member 30: Make-up water supply port 31: Make-up water supply source

Claims

1. A liquid ring pump, a first housing portion that houses the impeller and the sealing liquid; a second housing portion in which a mechanical seal that seals around a rotation shaft of the impeller is disposed; A motor that rotates the impeller; a suction port communicating with the first storage portion; a discharge port communicating with the first storage portion and discharging the sealing liquid; a circulating water supply port communicating with the first storage portion and through which circulating water used as the sealing liquid is supplied, A liquid ring pump that prevents the sealing liquid containing foreign matter in the first storage section from penetrating into the mechanical seal by supplying makeup water directly to the second storage section without passing through the first storage section.

2. The replenishment liquid flows from the second storage unit to the first storage unit.

2. A liquid ring pump as claimed in claim 1.

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