JP7383557B2 - pump - Google Patents

Description

TECHNICAL FIELD The present invention relates to a pump.

The pump disclosed in Patent Document 1 includes a lubricant flow path that supplies lubricant to a bearing that rotatably supports a rotating shaft. The lubricant flow path includes a protection tube disposed within the pump casing so as to surround the rotating shaft. The lubricant flow path is connected to an external water injection mechanism that supplies clean water (tap water) as a lubricant into the protection tube, and a self-water injection mechanism that supplies purified water, which is a part of the pumped water that has been filtered, as a lubricant into the protection tube. ing.

JP2020-7983A

In Patent Document 1, wasteful consumption of fresh water as a lubricant is suppressed by switching between a state in which fresh water is supplied by an external water injection mechanism and a state in which purified water is supplied by a self-injection mechanism. However, in Patent Document 1, no consideration is given to reducing leakage of lubricant from the lubricant flow path.

An object of the present invention is to provide a pump that can reduce leakage of lubricant from a lubricant flow path for protecting a bearing.

One aspect of the present invention includes a cylindrical pump casing, a rotating shaft having a first end disposed within the pump casing, and a second end disposed outside the pump casing; an impeller attached to a first end side; a bearing disposed adjacent to the second end side of the rotating shaft with respect to the impeller and rotatably supporting the rotating shaft; a protective tube connected to the second end of the rotating shaft and surrounding the rotating shaft; and a mechanical seal disposed on the impeller side with respect to the bearing, and a lubricant is supplied to the bearing through the protective tube. a lubricant flow path for supplying the lubricant, an external water injection mechanism that supplies fresh water from a water source outside the pump casing to the lubricant flow path as the lubricant, and a drainage path between the pump casing and the protection pipe. a self-water injection mechanism that supplies purified water obtained by filtering pumped water to the impeller side of the mechanical seal; a flow rate detection section that detects the amount of water supplied from the water source; and the self-water injection mechanism based on the measurement result of the flow rate detection section. and a control unit that controls the mechanism , and the control unit intermittently supplies or stops the supply of the purified water to the mechanical seal by the self-water injection mechanism when the measurement result of the flow rate detection unit is less than a threshold value. On the other hand, when the measurement result of the flow rate detection unit is equal to or higher than the threshold value, the self-water injection mechanism continuously supplies the purified water to the mechanical seal.

In this embodiment, purified water is supplied to the impeller side of the mechanical seal by a self-water injection mechanism. As a result, foreign matter adhering to the seal portion of the mechanical seal can be removed (flushing), and wear of the seal portion due to foreign matter can be suppressed. Furthermore, since the pressure on the impeller side of the mechanical seal is increased, leakage of lubricant from the lubricant flow path can be reduced. Therefore, wasteful consumption of expensive fresh water can be suppressed. Since purified water is not supplied to the lubricant flow path as the lubricant, even if the pumped water contains corrosive sulfides and chlorides, it is possible to prevent damage to the parts that make up the lubricant flow path. Moreover, when the measurement result of the flow rate detection unit is less than the threshold value, that is, when there is little lubricant leakage and the amount of clean water supplied is small, the self-water injection mechanism intermittently supplies clean water, causing foreign matter to stick to the mechanical seal. You can prevent this from happening. Therefore, when the pump is driven, wear of the mechanical seal due to foreign matter can be prevented. When the measurement result of the flow rate detection unit is above the threshold value, that is, when there is a lot of lubricant leakage and a large amount of clean water is supplied, the self-water injection mechanism continuously supplies clean water to reduce the pressure on the impeller side of the mechanical seal. Since the pressure is constantly increased, leakage of lubricant from the lubricant flow path can be reduced.

The self-water injection mechanism includes a first pipe having a first end connected to the drainage channel and a second end disposed outside the pump casing, and a first pipe connected to the second end of the first pipe. a filter having an inflow portion and a discharge portion for discharging the purified water; a second pipe having a first end connected to the discharge portion; and a second end connected to the impeller side of the mechanical seal. Equipped with.

In this aspect, without using a driving means such as an electric pump, a part of the pumped water flows into the first pipe due to the pressure of the pumped water flowing in the drainage channel, and the purified water that has been filtered by the filter is passed through the second pipe using a mechanical system. Can be discharged onto a seal.

The bearing is attached to a bearing casing fixed within the pump casing, and the protection tube is connected to an end of the rotating shaft on the second end side of the bearing casing via a fastened connection part. , the self-water injection mechanism includes a third pipe having a first end connected to the discharge section and a second end disposed at the connection section.

In this aspect, since purified water is supplied to the joint between the protection tube and the bearing casing by the self-water injection mechanism, leakage of lubricant from the joint can be reduced by the supply pressure of purified water. Therefore, wasteful consumption of fresh water can be suppressed.

The mechanical seal includes a first seal portion that seals the impeller side, a second seal portion that seals the bearing side, and a housing that accommodates these. A first injection hole to which the second piping of the self-water injection mechanism is connected corresponds to the first injection hole, and a second injection hole to which the external water injection mechanism is connected to correspond to the second seal portion are provided.

In this aspect, since the mechanical seal includes the first seal portion and the second seal portion, leakage of the lubricant from the lubricant flow path can be effectively suppressed. Furthermore, it is possible to reliably prevent the purified water supplied to the first seal portion from entering the lubricant flow path.

The external water injection mechanism includes a fourth pipe having a first end connected to the water source and a second end connected to the second injection hole .

In this aspect, since the pressure on the second seal portion side can be increased by supplying fresh water, leakage of the lubricant in the lubricant flow path can be suppressed.

The self-water injection mechanism includes a fifth pipe having a first end connected to the discharge part and a second end connected to the fourth pipe, and a connecting part between the fourth pipe and the fifth pipe. includes a switching section that switches the connection state so that one of the fourth piping and the fifth piping is connected to the second seal section.

In this aspect, it is possible to switch which of fresh water and purified water is supplied to the second seal portion. Therefore, by supplying clean water when the amount of lubricant leaking from the lubricant flow path is small, and supplying purified water when the amount of leakage is large, wasteful consumption of clean water can be suppressed.

a circulation pipe that is disposed outside the pump casing and communicates the first end side and the second end side of the rotating shaft in the lubricant flow path; and a delivery section that causes the lubricant to flow from the second end side to the first end side.

In this aspect, since the lubricant is flowed toward the bearing by the delivery portion, wear and overheating of the bearing can be effectively suppressed. Furthermore, since the pressure within the lubricant flow path is greater than the pressure at which purified water is supplied by the self-water injection mechanism, it is possible to prevent purified water supplied to the mechanical seal from entering the lubricant flow path.

With the pump of the present invention, leakage of lubricant from the lubricant flow path for protecting the bearing can be reduced.

1 is a sectional view showing a pump according to a first embodiment of the present invention. A sectional view of a mechanical seal. FIG. 3 is a cross-sectional view showing the connection between the bearing casing and the protection tube. A sectional view showing an example of a filter. Block diagram of the pump. 5 is a table showing control by the control unit according to the state of the lubricant flow path. FIG. 6B is a table showing the states of the valves according to the control of FIG. 6A. 5 is a table showing a modification example of control by the control unit according to the situation of the lubricant flow path.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a pump 10 according to a first embodiment of the invention. This pump 10 is of a standby type, in which operation is started in advance before water accumulates in the water suction tank 1, and switches to submerged operation, air/water mixing operation, and full water operation depending on the water level in the water suction tank 1.

As shown in FIG. 1, the pump 10 includes a pump casing 12, a rotating shaft 20, and an impeller 22, which have the same basic structure as a typical vertical shaft pump. The pump 10 also includes a lubricant flow path 30 for the purpose of protecting the bearings 24A and 24B of the rotating shaft 20, and an external water injection mechanism 50 for the purpose of replenishing the lubricant flow path 30 with lubricant (external fluid). Equipped with. The pump 10 of this embodiment differs from a general vertical shaft pump and a standby type pump in that a self-watering mechanism 60 is provided for the purpose of reducing leakage of lubricant from the lubricant flow path 30.

(Basic structure of pump)
As shown in FIG. 1, the pump casing 12 has a cylindrical shape and is fixed to an installation floor 2 that covers the upper part of the water absorption tank 1. The pump casing 12 includes a lift pipe 13 arranged in the water suction tank 1 so as to extend in the vertical direction, and a discharge pipe 17 arranged on the installation floor 2. The lift pipe 13 includes a straight pipe 14, a vane casing 15, and a bell mouth 16, which are connected in this order from top to bottom. The discharge pipe 17 includes a discharge elbow 18 bent at 90 degrees, and is connected to the upper end of the straight pipe 14 . A water pipe (not shown) for discharging water downstream is connected to the outlet of the discharge elbow 18 .

The rotating shaft 20 is arranged to extend vertically along the axis of the water pump 13. The rotating shaft 20 includes a first end 20a disposed within the pump casing 12 and a second end 20b disposed outside the pump casing 12. In the rotating shaft 20, most of the first end 20a side is disposed within the water pump 13, and the second end 20b side penetrates the discharge elbow 18 and projects outward.

The impeller 22 is disposed below the bearing casing 15a provided in the vane casing 15, and is attached to the lower end (first end 20a) of the rotating shaft 20 protruding from the bearing casing 15a. The upper end of the impeller 22 is located at a predetermined drainage start water level (lowest water level).

The pump casing 12 includes bearings 24A and 24B that rotatably support the rotating shaft 20. Of these, the bearing 24A is disposed within a sleeve 18a provided in a portion of the discharge elbow 18 through which the rotating shaft 20 passes. The bearing 24B is arranged in a sleeve 15b provided in a portion of the bearing casing 15a through which the rotating shaft 20 passes. Each bearing 24A, 24B includes a sliding body made of ceramic or resin with low thermal conductivity.

A drive unit 26 (see FIG. 5) is mechanically connected to the upper end (second end 20b) of the rotating shaft 20. For the drive unit 26, an electric motor or a diesel engine, which is one of internal combustion engines, can be used. By driving the drive unit 26, the impeller 22 is rotated together with the rotating shaft 20.

The pump 10 is started by an operator based on weather information, and initially operates in air with no water in the pump casing 12. When the water level in the water suction tank 1 becomes higher than a predetermined pumping cutoff water level (lower end of the intake pipe), a transition is made to an air/water mixing operation in which water and air sucked in from the suction port 16a are discharged together. When the water level becomes higher than the lowest water level in which the impeller 22 is completely immersed, a transition is made to full water operation in which only water is discharged.

When the water level drops below the lowest water level due to drainage, air is sucked in together with water from the suction port 16a of the pump casing 12, and the operation shifts to air-water mixing operation again. Thereafter, when the pumping cutoff water level is reached, a fixed amount of air is sucked in from the intake pipe, and the system shifts to an airlock operation in which the water column is maintained in the pumping pipe 13.

The airlock operation is maintained by continuing to drive the drive unit 26, and when the water in the water absorption tank 1 increases, the operation shifts to the full water operation again through the air-water mixing operation. When the operator stops the pump 10 based on weather information, the water column in the pump pipe 13 falls off.

When the pump is operated, the bearings 24A and 24B may be damaged (abrasive wear) by foreign matter contained in the pumped water. Further, during submerged operation, since there is no pumped water in the pump casing 12, the bearings 24A and 24B may overheat due to sliding contact with the rotating shaft 20, and there is a risk that they may seize. In order to prevent these problems and continue operation (rotation of the rotating shaft 20), the pump 10 is provided with a lubricant flow path 30, an external water injection mechanism 50, and a self-water injection mechanism 60.

The lubricant flow path 30 circulates the lubricant to lubricate the bearings 24A, 24B and the rotating shaft 20, thereby preventing seizure thereof. The external water injection mechanism 50 supplies (replenishes) clean water (tap water) as a lubricant to the lubricant flow path 30 . The self-water injection mechanism 60 reduces leakage of lubricant from the lubricant flow path 30 by supplying purified water obtained by filtering a portion of the pumped water to a predetermined portion. These will be specifically explained below.

(Overview of lubricant flow path)
Referring to FIG. 1, the lubricant flow path 30 includes a protection tube 31 disposed between a pair of bearings 24A and 24B, a mechanical seal 32A disposed outside of the bearings 24A and 24B in the axial direction of the rotating shaft 20, 32B. Furthermore, circulation piping 38 is connected to both ends of the lubricant flow path 30.

The protection tube 31 has a cylindrical shape surrounding the rotating shaft 20. The upper end of the protective tube 31 is fluid-tightly attached to the lower end of the sleeve 18a of the discharge elbow 18, and is connected to the bearing 24A in the sleeve 18a. The lower end of the protection tube 31 is connected to the bearing 24B inside the sleeve 15b by being attached in a fluid-tight manner to the upper end of the sleeve 15b of the bearing casing 15a. The space between the protection tube 31 and the rotating shaft 20 constitutes a flow path for circulating the lubricant. The space between the pump casing 12 and the protection tube 31 constitutes a drainage channel 28 through which water in the water absorption tank 1 is discharged.

The mechanical seal 32A located on the upper side in FIG. 1 is arranged above the bearing 24A. More specifically, the mechanical seal 32A is arranged on the lid 34 of the cylindrical enclosure 33 that projects outward from the discharge elbow 18. The lower end of the enclosure 33 is closed by a steel pipe constituting the discharge elbow 18, and the upper end of the enclosure 33 is closed by a separate lid 34. A through hole is formed in the center of the lid 34, and the rotating shaft 20 extends upward through this through hole. The mechanical seal 32A seals the rotating shaft 20 passing through the lid 34, and seals the internal space of the enclosure 33 communicating with the inside of the protection tube 31.

The mechanical seal 32B located on the lower side in FIG. 1 is arranged at the lower end (on the impeller 22 side) of the sleeve 15b (bearing 24B) of the bearing casing 15a. The mechanical seal 32B seals the rotating shaft 20 and the lower end of the sleeve 18a communicating with the inside of the protection tube 31.

The mechanical seals 32A, 32B include a rotating ring attached to the rotating shaft 20 and a fixed ring attached to the housing, and the sliding contact between these rings prevents leakage of the lubricant in the lubricant flow path 30. For example, the upper mechanical seal 32A uses a single type including one rotating ring and one fixed ring. The lower mechanical seal 32B uses a double type having two rotating rings and two fixed rings.

FIG. 2 shows an example of a double type mechanical seal 32B. The mechanical seal 32B in FIG. 2 has a tandem shape in which a pair of rotating rings 32a1 and 32a2 are urged in the same direction (upward). However, the mechanical seal 32B may be of a back-to-back type in which the pair of rotating rings 32a1 and 32a2 are biased away from each other, or may be of a back-to-back type in which the pair of rotating rings 32a1 and 32a2 are biased toward each other. It may be a shape.

As shown in FIG. 2, the double-type mechanical seal 32B includes a first seal part 32c1 made up of a rotating ring 32a1 and a fixed ring 32b1, and a second seal part 32c1 made up of a rotating ring 32a2 and a fixed ring 32b2. 32c2. These are arranged side by side in the axial direction with respect to the rotating shaft 20 and housed in a cylindrical housing 32d. The first seal portion 32c1 is arranged on the impeller 22 side (lower side) and mainly prevents pumped water from flowing into the bearing 24B from the drainage channel 28. The second seal portion 32c2 is arranged on the bearing 24B side (upper side) and mainly prevents the lubricant from leaking from the lubricant flow path 30 toward the drain path 28.

A pair of injection holes 32e1 and 32e2 are provided in the housing 32d. The first injection hole 32e1 is provided at a position corresponding to the first seal portion 32c1 in the axial direction of the housing 32d, and penetrates the housing 32d in the radial direction. The second injection hole 32e2 is provided at a position corresponding to the second seal portion 32c2 in the axial direction of the housing 32d, and penetrates the housing 32d in the radial direction. As will be described in detail later, a self-water injection mechanism 60 is connected to the first injection hole 32e1 in order to supply purified water to the first seal portion 32c1. In order to supply fresh water to the second seal portion 32c2, an external water injection mechanism 50 is connected to the second injection hole 32e2.

As shown in FIG. 1, the circulation piping 38 is arranged outside the pump casing 12. One end (upper end) of the circulation pipe 38 is connected to a lubricant tank 35 , and connected to the upper end (one end) of the lubricant flow path 30 via the lubricant tank 35 . The other end (lower end) of the circulation pipe 38 is connected to a flexible pipe 38a attached to the outside of the vane casing 15, and the lubricant flow path 30 is connected to the flexible pipe 38a, the connecting pipe part 15c, and the sleeve 15b. Connected to the lower end (other end). Thereby, one end side and the other end side of the lubricating fluid flow path 30 are communicated via the circulation pipe 38.

The lubricant tank 35 is mounted on the lid 34 via a pedestal, and is connected to an injection hole (not shown) of the mechanical seal 32A through a connecting pipe 39. A full water detector 37 is arranged in the lubricant tank 35 to detect the level of the lubricant. The lubricant tank 35 is a hollow toroidal body having an opening in the center, and a ball bearing 36, which is a thrust bearing for the rotating shaft 20, is fixed to the opening.

The flexible pipe 38a is a flexible and deformable pipe, and is connected to the connecting pipe portion 15c of the vane casing 15. The flexible pipe 38a is provided to suppress the vibrating piping load applied to the piping due to vibration during the preliminary standby operation, and to prevent damage to the piping. The connecting pipe portion 15c extends from the outer circumferential surface of the vane casing 15, passes through the bearing casing 15a, and extends to the sleeve 15b. Thereby, a flow channel is formed that communicates from the inside of the sleeve 15b to the outside of the vane casing 15 (flexible pipe 38a).

A vane member (delivery section) 41 that causes lubricant to flow from the upper end (second end 20b) side of the rotating shaft 20 toward the bearing 24B is arranged within the enclosure section 33. The vane member 41 is attached to the rotation shaft 20 and rotates together with the rotation shaft 20 to circulate the lubricant in the lubricant flow path 30 and the circulation pipe 38 clockwise in FIG. 1 . Further, the circulation pipe 38 is provided with a flow rate adjustment valve 40 that adjusts the circulation flow rate of the lubricant.

The lubricating fluid within the enclosure 33 flows downward in FIG. 1 through the gap between the sleeve 18a (bearing 24A) and the rotating shaft 20, and flows into the protection tube 31. Subsequently, the lubricating fluid flows downward in the figure in the protective tube 31, passes through the gap between the sleeve 15b (bearing 24B) of the bearing casing 15a and the rotating shaft 20, and further flows into the circulation pipe 38 via the connecting pipe portion 15c. Inflow. Subsequently, the lubricant moves up the circulation pipe 38 to reach the lubricant tank 35, and returns into the enclosure 33 through the connection pipe 39 and the housing of the mechanical seal 32A.

The bearings 24A, 24B within the sleeves 18a, 15b are lubricated by the lubricating fluid thus circulated. Further, the mechanical seals 32A and 32B prevent the lubricant from leaking from the inside of the lubricant flow path 30 to the outside.

(Outline of external water injection mechanism)
As shown in FIG. 1, the external water injection mechanism 50 includes a water tank (water source) 52 connected to water source equipment (not shown). The external water injection mechanism 50 also includes a first water supply pipe 55 for supplying (replenishing) fresh water as a lubricant to the lubricant flow path 30, and a second water supply pipe 55 for supplying fresh water to the second seal portion 32c2. 4th piping) 56, which are branched and connected to the water receiving tank 52.

The water receiving tank 52 is arranged at a higher position than the lubricant tank 35 and is connected to water source equipment via a connecting pipe 53. A ball tap valve (not shown) is interposed in the connecting pipe 53 as a water stop valve that cuts off communication between the water source equipment and the water tank 52 when fresh water is stored in the water tank 52 to a predetermined water level. There is. Furthermore, a flow meter (flow rate detection section) 54 is interposed in the connection pipe 53 to measure the flow rate of fresh water supplied from the water source equipment to the water receiving tank 52, that is, the amount of water supplied to the circulation channel 30.

The first water supply pipe 55 has one end (first end) connected to the water receiving tank 52 and the other end (second end) connected to the circulation pipe 38, and is connected to the lubricant tank via the circulation pipe 38. 35 (lubricant flow path 30). That is, the first water supply pipe 55 is connected to the lubricant tank 35 using part of the circulation pipe 38 as a common pipe. However, the first water supply pipe 55 may be directly connected to the lubricant tank 35 without sharing a part of the circulation pipe 38.

The second water supply pipe 56 includes a first end 56a connected to the first water supply pipe 55 and a second end 56b (see FIG. 2) connected to the mechanical seal 32B. The second water supply pipe 56 (first end 56a) is connected to the water receiving tank 52 using a part of the first water supply pipe 55 as a common pipe. However, the second water supply pipe 56 may be directly connected to the water receiving tank 52 without sharing a part of the first water supply pipe 55. The second water supply pipe 56 (second end 56b) is connected to the second injection hole 32e2 (that is, the second seal portion 32c2 side) of the mechanical seal 32B.

In the first water supply pipe 55, a first solenoid valve 57 is interposed on the upstream side (the water receiving tank 52 side) of the connection part (first end 56a) with the second water supply pipe 56. Further, a second solenoid valve 58 and a check valve 59 are interposed in the second water supply pipe 56 . The first electromagnetic valve 57 can be switched between an open state in which the fresh water in the water receiving tank 52 can be supplied and a closed state in which the fresh water in the water receiving tank 52 cannot be supplied. The second electromagnetic valve 58 can be switched between a state in which supply of fresh water from the water tank 52 to the mechanical seal 32B is possible and a state in which it is not possible. The check valve 59 allows water to flow from the water tank 52 toward the mechanical seal 32B, and prevents water from flowing in the opposite direction.

Due to the operation of the pump 10, wear (deterioration) of the rotating rings 32a1, 32a2 and fixed rings 32b1, 32b2 of the mechanical seal 32B, which are consumable parts, is unavoidable, so the lubricant leaks from the lubricant flow path 30 over time. arise. When the lubricant in the lubricant flow path 30 becomes insufficient due to this leakage, fresh water in the water receiving tank 52 is supplied to the lubricant tank 35 via the water supply pipe 55 due to water head pressure. Thereby, the lubricant in the lubricant flow path 30 including the circulation pipe 38 is always maintained at a fixed amount.

(Overview of self-water injection mechanism)
Continuing to refer to FIG. 1, the self-water injection mechanism 60 prevents leakage of lubricant from the lubricant flow path 30 by filtering a portion of the pumped water and discharging purified water to a predetermined portion of the lubricant flow path 30. reduce The self-water injection mechanism 60 includes a spout pipe (first pipe) 61 connected to the drainage channel 28, a filter 62 connected to the spout pipe 61, and a first water supply pipe (second pipe) connected to the filter 62. (piping) 63, and a water storage tank 64 for storing a predetermined amount of purified water. The self-water injection mechanism 60 further includes a second water supply pipe (third pipe) 65 and a third water supply pipe (fifth pipe) 66 connected to the filter 62.

The spouting pipe 61 includes a first end 61a connected to the drainage channel 28 inside the pump casing 12 and a second end 61b disposed outside the pump casing 12, and communicates the pump casing 12 and the filter 62. let The first end 61a is connected to the discharge elbow 18 and communicates with the downstream side of the impeller 22, which has the highest pressure in the drainage channel 28. The second end 61b is connected to the pumped water inlet 62c of the filter 62. A portion of the pumped water flows out into the spout pipe 61 due to the discharge pressure of the pumped water in the drainage channel 28 .

The filter 62 includes a pumped water inlet (inflow part) 62c and a purified water outlet (discharge part) 62d connected to the second end 61b, filters the pumped water flowing in from the spout pipe 61, and converts the purified water into a purified water stream. It is discharged from the outlet 62d. The filter 62 is constituted by a cyclone separator that separates pumped water into clean water and waste water. However, the type of filter 62 can be changed as necessary, as long as it is configured to remove foreign matter in the pumped water and discharge purified water.

FIG. 4 shows a cyclone separator type filter 62. This filter 62 includes a container 62a having a conical cylindrical portion at one end, and a lid portion 62b that closes the other end of the container 62a. The pumped water inlet 62c is formed in the outer peripheral portion of the container 62a on the lid portion 62b side. The purified water outlet 62d is a portion from which purified water from which foreign matter has been removed by centrifugation flows out, and is formed in the lid portion 62b. A sewage outlet 62e is formed in the container 62a so as to be located on the opposite side of the lid 62b, through which sewage containing separated foreign matter is discharged.

A drain pipe 62f is connected to the wastewater outlet 62e. Referring to FIG. 1, the tip of the drain pipe 62f is connected to the bell mouth 16 on the upstream side of the impeller 22 so as to communicate with a lower pressure portion of the drain passage 28 than the inside of the filter 62.

As shown in FIG. 1, the first water supply pipe 63 is a pipe that supplies purified water to the first seal portion 32c1 (impeller 22 side) exposed to the drainage channel 28 in the mechanical seal 32B. The first water supply pipe 63 includes a first end 63a connected to the purified water outlet 62d and a second end 63b (see FIG. 2) connected to the first seal portion 32c1, and includes the filter 62 and the mechanical seal 32B. communicate.

A water tank 64 is interposed in the first water supply pipe 63 . That is, the first water supply pipe 63 of this embodiment includes a first portion 63c that communicates the filter 62 and the water tank 64, and a second portion 63d that communicates the water tank 64 and the mechanical seal 32B. One end of the first portion 63c is a first end 63a connected to the purified water outlet 62d, and the other end of the first portion 63c is connected to the water tank 64. One end of the second portion 63d is connected to the water tank 64, and the other end of the second portion 63d is the second end 63b connected to the first seal portion 32c1.

The water tank 64 is a container that is arranged at a higher position than the lubricant tank 35 and stores purified water discharged from the filter 62. In order to avoid poor water supply due to insufficient purified water, a water level sensor 64a (see FIG. 5) is arranged in the water storage tank 64 to detect the amount of water stored (water level).

The second water supply pipe 65 is a pipe that supplies purified water to the connection portion 30a between the protection pipe 31 and the bearing casing 15a in the lubricant flow path 30. The second water supply pipe 65 includes a first end 65a connected to the second portion 63d of the first water supply pipe 63, and a second end 65b (see FIG. 3) connected to the connecting portion 30a. That is, the second water supply pipe 65 (first end 65a) is connected to the water tank 64 (filter 62) using a part of the first water supply pipe 63 as a common pipe. However, the second water supply pipe 65 may be directly connected to the water tank 64 without sharing a part of the first water supply pipe 63.

FIG. 3 shows a connecting portion 30a between the protective tube 31 and the bearing casing 15a. As shown in FIG. 3, the lower end of the protection tube 31 is formed with an annular flange portion 31a that projects radially outward. An annular flange portion 15d is formed at the upper end of the bearing casing 15a, protruding outward in the radial direction and corresponding to the flange portion 31a. These flange portions 31a, 15d are fastened together with bolts (not shown).

The flange portion 31a of the protection tube 31 has an annular water supply groove 31b recessed in a direction away from the flange portion 15d on a surface facing the flange portion 15d of the bearing casing 15a, and a communication hole 31c communicating with the water supply groove 31b. is provided. On both sides of the water supply groove 31b in the radial direction of the flange portion 31a, grooves 31d in which packing is arranged are provided. The second end 65b of the second water supply pipe 65 is connected to the water supply groove 31b, and by increasing the internal pressure of the water supply groove 31b by supplying purified water, lubrication is carried out from between the flanges 31a and 15d to the outside of the lubricant flow path 30. Prevents liquid leakage.

The third water supply pipe 66 is a pipe that supplies purified water to the second seal portion 32c2 on the bearing 24B side in the mechanical seal 32B. The third water supply pipe 66 includes a first end 66 a connected to the second water supply pipe 65 and a second end 66 b connected to the second water supply pipe 56 . That is, the third water supply pipe 66 (first end 66a) is connected to the water tank 64 (filter 62) using a part of the second water supply pipe 65 as a common pipe. However, the third water supply pipe 66 may be directly connected to the water tank 64 without sharing a part of the second water supply pipe 65.

The self-water injection mechanism 60 configured in this manner functions by the pressure within the pump casing 12.

Specifically, as shown in FIG. Assuming that the pressure in the second portion 63d is P3, the pressure in the drain pipe 62f is P4, and the pressure in the bell mouth 16 is P5, during full water operation, the pressures P1, P2, P3, P4, and P5 are in this order. (P1>P2≧P3>P4>P5). However, there is a situation where the pressure P2 in the first portion 63c and the pressure P3 in the second portion 63d are the same.

A portion of the pumped water within the pump casing 12 is supplied to the filter 62 through the outlet pipe 61 due to the pressure difference described above. Referring to FIG. 4, the pumped water PW that has flowed into the filter 62 swirls along the inner wall of the container 62a (see swirling flow RF). As a result, the pressure near the inner wall of the container 62a becomes high, and the pressure near the central axis of the container 62a becomes low. Further, in the vicinity of the central axis of the container 62a, a flow UF toward the purified water outlet 62d occurs on the lid portion 62b side, and only a swirling flow toward the dirty water outlet 62e occurs on the opposite side.

The solids contained in the pumped water PW are separated by the centrifugal force caused by the swirling flow RF, rotate toward the wastewater outlet 62e, and are discharged as wastewater DW from the wastewater outlet 62e to the drain pipe 62f. This dirty water DW is discharged into the pump casing 12 through the drain pipe 62f (see FIG. 1).

The purified water CW from which solids have been separated is discharged from the purified water outlet 62d to the first portion 63c. However, fine solids that do not cause wear on the bearings 24A, 24B may be discharged from the purified water outlet 62d while being contained in the purified water CW. As shown in FIG. 1, the purified water CW that has flowed into the first portion 63c is temporarily stored in the water storage tank 64. This purified water CW is supplied to the mechanical seal 32B and the connecting portion 30a according to commands from the control section 80, which will be described later.

Referring to FIG. 1, the self-water injection mechanism 60 includes a solenoid valve 67 for pumping and discharging water, solenoid valves 68 and 69 for supplying clean water, and a solenoid valve 70 for discharging waste water. A switching valve 71 that switches the connection state with the mechanical seal 32B is disposed at the connection between the second water supply pipe 56 for fresh water and the third water supply pipe 66 for purified water.

The solenoid valve 67 is interposed in the pouring pipe 61 and can be switched between an open state in which pumped water can be poured out from the pump casing 12 to the filter 62 and a closed state in which pumping is not possible.

The solenoid valve 68 is interposed in the second portion 63d of the first water supply pipe 63 on the downstream side (mechanical seal 32B side) of the connection part (first end 65a) with the second water supply pipe 65, and is connected to the water storage tank 64. It is possible to switch between an open state in which purified water can be supplied to the first seal portion 32c1 and a closed state in which supply is not possible.

The electromagnetic valve 69 is interposed in the second water supply pipe 65 and can be switched between an open state in which purified water can be supplied from the water tank 64 to the connecting portion 30a, and a closed state in which supply is not possible.

The solenoid valve 70 is interposed in the drain pipe 62f, and can be switched between an open state in which wastewater can be discharged from the filter 62 to the pump casing 12, and a closed state in which discharge is not possible.

The switching valve 71 is in the first connection state so that one of the second water supply pipe 56 for fresh water and the third water supply pipe 66 for purified water is connected to the second seal portion 32c2 of the mechanical seal 32B. It is a three-way valve that can be switched to a second connected state. In the first connection state, the second water supply pipe 56 for clean water and the second seal part 32c2 are in communication, and the third water supply pipe 66 for purified water and the second seal part 32c2 are cut off. In the second connected state, the third water supply pipe 66 for purified water and the second seal part 32c2 are in communication, and the second water supply pipe 56 for fresh water and the second seal part 32c2 are cut off.

(Overview of control unit)
As shown in FIG. 5, the pump 10 includes a control section 80 configured by a personal computer or the like. The control unit 80 is electrically connected to the drive unit 26, the aforementioned sensors 37, 54, and 64a, and the aforementioned valves 40, 57, 58, and 67 to 71. The control unit 80 controls the drive unit 26 according to the operator's instructions, and also controls the flow rate adjustment valve 40, the electromagnetic valves 57, 58, 67 to 70, and the switching valve 71 according to the measurement results of the various sensors 37, 54, 64a. .

The control unit 80 includes a storage unit (memory) 81 in which a program for controlling the pump 10 and threshold values used in the program are stored. The program of the control unit 80 includes water injection processing aimed at reducing lubricant leakage from the lubricant flow path 30. This water injection process is performed in parallel with driving of the drive unit 26. Regardless of the state of the water injection process, in the drive process, the rotating shaft 20 is rotated at a constant speed by the drive unit 26.

In the water injection process, the state of the mechanical seal 32B, that is, the presence or absence of an abnormality in the mechanical seal 32B and the abnormality level are determined based on the measurement results of the flowmeter 54, and the external water injection mechanism 50 and the self-water injection mechanism 60 are control. The storage unit 81 stores threshold values T1 and T2 for determining the state of the mechanical seal 32B. The first threshold T1 is smaller than the second threshold T2 (T1<T2).

Specifically, the measurement result (flow rate) of the flowmeter 54 within a predetermined period increases as the amount of leakage from the lubricant flow path 30 (that is, the mechanical seal 32B) increases. In other words, a situation where the amount of water supplied from the water receiving tank 52 is small means that the mechanical seal 32B is less worn and there is no damage to the mechanical seal 32B. On the other hand, a situation where the amount of water supplied from the water tank 52 is large means that the mechanical seal 32B is worn a lot and the mechanical seal 32B itself may be damaged. Therefore, by comparing the measurement result of the flow meter 54 with the threshold values T1 and T2, the control unit 80 can determine the state of the mechanical seal 32B.

(Main flow by control unit)
The control unit 80 starts and stops the drive unit 26 according to the operator's instructions as described above. When the drive unit 26 is started, the control unit 80 executes one of normal operation, abnormal operation, and emergency operation based on the measurement result of the flow meter 54 until a stop command is input.

More specifically, when the measurement result of the flowmeter 54 is less than the first threshold value T1, the control unit 80 determines that the mechanical seal 32B is in a normal state, and performs steady-state operation. If the measurement result of the flow meter 54 is greater than or equal to the first threshold value T1 and less than the second threshold value T2, the control unit 80 determines that the mechanical seal 32B is in an abnormal state due to wear, and performs abnormal operation. If the measurement result of the flow meter 54 is equal to or greater than the second threshold T2, the control unit 80 determines that the mechanical seal 32B is in an emergency state where it is excessively worn or damaged, and performs emergency operation.

As shown in FIG. 6A, the lubricant flow path 30 is replenished with fresh water from the external water injection mechanism 50 regardless of the operating state (that is, the state of the mechanical seal 32B). Further, depending on the operating state, purified water is supplied from the self-water injection mechanism 60 to the first seal part 32c1, and clean water from the external water injection mechanism 50 or purified water from the self-water injection mechanism 60 is supplied to the second seal part 32c2. , purified water is supplied from the self-water injection mechanism 60 to the connecting portion 30a.

(Steady operation)
Referring to FIG. 6A, during normal operation when there is no abnormality in the mechanical seal 32B, the control unit 80 replenishes the lubricant flow path 30 with fresh water and supplies the first seal portion 32c1, the second seal portion 32c2, and the connecting portion 30a with fresh water. does not provide fresh or purified water.

Referring to FIG. 6B, during steady-state operation, the control unit 80 opens the solenoid valve 57 for supplying fresh water to the lubricant flow path 30. In this state, the lubricant flow path 30 is replenished with fresh water in the water receiving tank 52 only when the pumped water in the lubricant flow path 30 is insufficient.

Further, the control unit 80 interlocks and intermittently opens and closes the electromagnetic valve 67 for pumping and pouring water and the electromagnetic valve 70 for discharging wastewater. Here, "opening and closing intermittently" means that the pump 10 is opened and closed for about 1 to 5 minutes when the pump 10 is started and stopped, and when the water level sensor 64a detects that the amount of purified water in the water tank 64 is low. , means to be in a closed state. Thereby, the purified water in the water tank 64 can be maintained in a full state.

Further, the control unit 80 closes the solenoid valve 58 for supplying fresh water to the second seal portion 32c2 and the solenoid valve 69 for supplying purified water to the second seal portion 32c2, and closes the switching valve 71. It is communicated with the external water injection mechanism 50 side. In this state, both the electromagnetic valves 58 and 69 are closed, so neither fresh water nor purified water is supplied to the second seal portion 32c2.

Further, the control unit 80 closes the solenoid valve 68 for supplying purified water to the first seal portion 32c1. In this state, since the electromagnetic valve 68 is in a closed state, purified water is not supplied to the first seal portion 32c1.

(Operation during abnormality)
Referring to FIG. 6A, during abnormal operation when an abnormality such as wear exists in the mechanical seal 32B, the control unit 80 replenishes the lubricant flow path 30 with fresh water and intermittently supplies purified water to the first seal portion 32c1. , supplies clean water to the second seal portion 32c2, and supplies purified water to the connecting portion 30a.

Referring to FIG. 6B, during abnormal operation, the control unit 80 opens the electromagnetic valve 57 for supplying fresh water to the lubricant flow path 30, similarly to the normal operation.

Further, the control unit 80 interlocks and intermittently opens and closes the electromagnetic valve 67 for pumping and discharging water and the electromagnetic valve 70 for discharging sewage, similarly to the steady state operation.

Further, the control unit 80 opens the solenoid valve 58 for supplying clean water to the second seal portion 32c2, closes the solenoid valve 69 for supplying purified water to the second seal portion 32c2, and closes the solenoid valve 58 for supplying clean water to the second seal portion 32c2. is communicated with the external water injection mechanism 50 side. In this state, the second seal part 32c2 is replenished with fresh water in the water receiving tank 52 only when the lubricating fluid in the second seal part 32c2 is insufficient. Further, the pressure inside the second seal portion 32c2 is increased by the water head pressure of the water receiving tank 52. Therefore, leakage of the lubricant in the lubricant flow path 30 passing through the second seal portion 32c2 can be suppressed.

Further, the control unit 80 intermittently opens and closes the solenoid valve 68 for supplying purified water to the first seal portion 32c1. Here, opening and closing intermittently means that when the pump 10 is started and stopped, it is opened for about 1 to 5 minutes and then closed. Thereby, at the time of startup, it is possible to remove (flushing) dust (foreign matter) that has adhered to and dried on the first seal portion 32c1 without water in the pump casing 12. Further, when the engine is stopped, foreign matter attached to the first seal portion 32c1 can be removed. Therefore, it is possible to suppress wear and damage of the rotating ring 32a1 and the fixed ring 32b1 due to foreign matter.

(Emergency operation)
Referring to FIG. 6A, in an emergency operation in which an abnormality such as excessive wear or damage exists in the mechanical seal 32B, the control unit 80 replenishes the lubricant flow path 30 with clean water, and the first seal part 32c1, the second seal Purified water is continuously supplied to the section 32c2 and the connecting section 30a.

Referring to FIG. 6B, in the emergency operation, the control unit 80 opens the solenoid valve 57 for supplying fresh water to the lubricant flow path 30, as in the normal operation.

Further, the control unit 80 opens the electromagnetic valve 67 for pumping and discharging water and the electromagnetic valve 70 for discharging wastewater. Thereby, a part of the pumped water in the pump casing 12 always flows out to the filter 62, and filtered purified water is continuously generated.

The control unit 80 also closes the solenoid valve 58 for supplying clean water to the second seal portion 32c2, opens the solenoid valve 69 for supplying purified water to the second seal portion 32c2, and closes the solenoid valve 58 for supplying clean water to the second seal portion 32c2. is communicated with the self-water injection mechanism 60 side. In this state, purified water in the water tank 64 is replenished into the second seal portion 32c2. Further, the pressure inside the second seal portion 32c2 is increased by the head pressure of the water tank 64. Therefore, leakage of the lubricant in the lubricant flow path 30 passing through the second seal portion 32c2 can be suppressed.

Further, the control unit 80 opens the solenoid valve 68 for supplying purified water to the first seal portion 32c1. As a result, purified water in the water tank 64 is continuously supplied to the first seal part 32c1, and the pressure in the first seal part 32c1 is increased by the water head pressure in the water tank 64. That is, since both the seal portions 32c1 and 32c2 of the mechanical seal 32B are pressurized, leakage of the lubricant in the lubricant flow path 30 through the mechanical seal 32B can be suppressed.

The pump 10 of this embodiment has the following features.

The self-water injection mechanism 60 supplies purified water to the impeller 22 side of the mechanical seal 32B. Thereby, foreign matter attached to the seal portion 32c1 of the mechanical seal 32B can be removed (flushing), so that wear of the seal portion 32c1 due to foreign matter can be suppressed. Furthermore, since the pressure on the impeller 22 side of the mechanical seal 32B is increased, leakage of lubricant from the lubricant flow path 30 can be reduced. Therefore, wasteful consumption of expensive fresh water can be suppressed. Since purified water is not supplied to the lubricant flow path 30 as the lubricant, even if the pumped water contains corrosive sulfides and chlorides, it is possible to prevent the parts constituting the lubricant flow path 30 from being damaged. .

The self-water injection mechanism 60 includes a spout pipe 61 connected to the drain channel 28, a filter 62 connected to the spout pipe 61, and a first water supply pipe 63 connected to the filter 62 and the mechanical seal 32B. Be prepared. Therefore, without using a driving means such as an electric pump, a part of the pumped water flows into the spout pipe 61 due to the pressure of the pumped water flowing in the drain channel 28, passes through the first water supply pipe 63, and is filtered by the filter 62. Purified water can be discharged to the mechanical seal 32B.

A second water supply pipe 65 for supplying purified water to the self-water injection mechanism 60 is provided at the connection portion 30a between the bearing casing 15a to which the bearing 24B is attached and the protection pipe 31. Therefore, the leakage of lubricating fluid from the connection portion 30a can be reduced by the supply pressure of purified water, so that wasteful consumption of fresh water can be suppressed.

Since the mechanical seal 32B includes the first seal portion 32c1 and the second seal portion 32c2, leakage of lubricant from the lubricant flow path 30 can be effectively suppressed. Furthermore, since purified water is supplied to the first seal portion 32c1 that seals the impeller 22 side, it is possible to reliably prevent purified water from entering the lubricant flow path 30.

The external water injection mechanism 50 includes a second water supply pipe 56 that supplies fresh water to the second seal portion 32c2 side. Therefore, since the pressure on the second seal portion 32c2 side can be increased, leakage of the lubricant in the lubricant flow path 30 can be suppressed. Moreover, even if the supplied fresh water flows into the lubricant flow path 30, the components that constitute the lubricant flow path 30 are not affected.

The self-water injection mechanism 60 includes a third water supply pipe 66 for supplying purified water to the second seal portion 32c2, and a switching valve 71 at the connection between the second water supply pipe 56 and the third water supply pipe 66. In other words, either fresh water or purified water can be supplied to the second seal portion 32c2. Therefore, by supplying clean water when the amount of lubricant leaking from the lubricant flow path 30 is small (during abnormal operation) and supplying purified water when the amount of leakage is large (during emergency operation), clean water can be supplied. Wasteful consumption can be suppressed.

Since the pump casing 12 includes the circulation pipe 38 disposed outside the pump casing 12 and the vane member 41 that causes the lubricant in the lubricant flow path 30 to flow, wear and overheating of the bearings 24A and 24B can be effectively suppressed. Furthermore, since the pressure within the lubricant flow path 30 is greater than the pressure at which purified water is supplied by the self-water injection mechanism 60, it is possible to prevent the purified water supplied to the mechanical seal 32B from entering the lubricant flow path 30.

It includes a flow meter 54 that detects the amount of water supplied from the water receiving tank 52, and a control section 80 that controls the self-water injection mechanism 60 based on the measurement results of the flow meter 54. That is, since the supply state of purified water is switched according to the amount of water supplied from the water receiving tank 52, wasteful consumption of fresh water can be reliably reduced.

Specifically, when the measurement result of the flow meter 54 is less than the threshold value T2, that is, when there is little lubricant leakage and the amount of fresh water supplied is small, the control unit 80 causes the self-water injection mechanism 60 to intermittently supply purified water. do. Therefore, it is possible to suppress the state in which foreign matter adheres to the mechanical seal 32B, so that wear of the mechanical seal 32B due to foreign matter can be prevented when the pump is driven.

On the other hand, when the measurement result of the flow meter 54 is equal to or higher than the threshold value T2, that is, when there is a large amount of lubricant leakage and a large amount of clean water is supplied, purified water is continuously supplied by the self-water injection mechanism 60. In other words, since the pressure on the impeller 22 side of the mechanical seal 32B is constantly increased, leakage of lubricant from the lubricant flow path 30 can be reduced.

Note that the pump 10 of the present invention is not limited to the configuration of the embodiment described above, and various changes can be made.

For example, as shown in FIG. 7, the control unit 80 may intermittently supply purified water from the self-water injection mechanism 60 to the first seal portion 32c1 during steady operation. Further, during abnormal operation, the control unit 80 may supply purified water from the self-water injection mechanism 60 to the second seal portion 32c2. Further, during abnormal operation, the control unit 80 may supply fresh water from the external water injection mechanism 50 to the connection unit 30a.

The impeller 22 side of the lubricant flow path 30 may be closed without providing the circulation pipe 38 . Purified water from the self-water injection mechanism 60 does not need to be supplied to the connection portion 30a between the bearing casing 15a and the protection tube 31. The mechanical seal 32B may be of a single type. Only purified water from the self-water injection mechanism 60 may be supplied to the second seal portion 32c2, and fresh water from the external water injection mechanism 50 may not be supplied. The control (water injection process) by the control unit 80 can be changed as necessary.

The pump is not limited to a standby type that starts operation in advance before water flows into the water absorption tank 1, but may be a vertical shaft pump that starts operation when a predetermined amount of water has accumulated. Further, the pump is not limited to a vertical shaft pump in which the rotating shaft is arranged to extend in the vertical direction, but may be a horizontal shaft pump in which the rotating shaft is arranged to extend in the horizontal direction.

1... Water absorption tank 2... Installation floor 10... Pump 12... Pump casing 13... Lifting pipe 14... Straight pipe 15... Vane casing 15a... Bearing casing 15b... Sleeve 15c... Connection pipe section 15d... Flange section 16... Bell mouth 16a... Suction Mouth 17...Discharge pipe 18...Discharge elbow 18a...Sleeve 20...Rotating shaft 20a...First end 20b...Second end 22...Impeller 24A, 24B...Bearing 26...Driving means 28...Drain channel 30...Lubricant flow path 30a ...Connection part 31...Protection tube 31a...Flange part 31b...Water supply groove 31c...Communication hole 31d...Concave groove 32A, 32B...Mechanical seal 32a1, 32a2...Rotating ring 32b1, 32b2...Fixed ring 32c1...First seal part 32c2...No. 2 Seal part 32d... Housing 32e1, 32e2... Injection hole 33... Enclosing part 34... Lid 35... Lubricating liquid tank 36... Ball bearing 37... Full water detector 38... Circulation piping 38a... Flexible pipe 39... Connection piping 40... Flow rate adjustment Valve 41...Blade member (delivery part)
50...External water injection mechanism 52...Water tank (water source)
53... Connection piping 54... Flowmeter (flow rate detection part)
55...First water supply pipe 56...Second water supply pipe (fourth pipe)
56a...First end 56b...Second end 57...First solenoid valve for fresh water supply 58...Second solenoid valve for fresh water supply 59...Check valve 60...Self-water injection mechanism 61... Output pipe (first piping)
61a...First end 61b...Second end 62...Filter 62a...Container 62b...Lid part 62c...Pumping water inlet (inflow part)
62d...Purified water outlet (discharge part)
62e...Sewage outlet 62f...Drain pipe 63...First water supply pipe (second pipe)
63a...First end 63b...Second end 63c...First part 63d...Second part 64...Water tank 64a...Water level sensor 65...Second water supply pipe (third pipe)
65a...First end 65b...Second end 66...Third water supply pipe (fifth pipe)
66a...First end 66b...Second end 67...Solenoid valve for pumping and pouring out water 68, 69...Solenoid valve for supplying clean water 70...Solenoid valve for discharging waste water 71...Switching valve (switching part)
80...Control unit 81...Storage unit

Claims (7)

a cylindrical pump casing,
a rotating shaft having a first end disposed within the pump casing and a second end disposed outside the pump casing;
an impeller attached to the first end side of the rotating shaft;
a bearing that is arranged adjacent to the second end side of the rotating shaft with respect to the impeller and rotatably supports the rotating shaft;
a protective tube that is connected to the second end of the rotating shaft with respect to the bearing and surrounds the rotating shaft; and a mechanical seal that is disposed on the impeller side with respect to the bearing; a lubricant flow path for supplying lubricant to the bearing;
an external water injection mechanism that supplies fresh water from a water source outside the pump casing to the lubricant flow path as the lubricant;
a self-water injection mechanism that supplies purified water obtained by filtering pumped water flowing out from a drainage channel between the pump casing and the protection pipe to the impeller side of the mechanical seal ;
a flow rate detection unit that detects the amount of water supplied from the water source;
a control unit that controls the self-water injection mechanism based on the measurement result of the flow rate detection unit;
Equipped with
The control unit includes:
When the measurement result of the flow rate detection unit is less than a threshold value, the self-water injection mechanism intermittently supplies or stops supplying the purified water to the mechanical seal;
The pump causes the self-water injection mechanism to continuously supply the purified water to the mechanical seal when the measurement result of the flow rate detection unit is equal to or higher than the threshold value. The self-watering mechanism includes:
a first pipe having a first end connected to the drainage channel and a second end disposed outside the pump casing;
a filter having an inflow part connected to the second end of the first pipe and a discharge part that discharges the purified water;
The pump according to claim 1, further comprising: a second pipe having a first end connected to the discharge portion and a second end connected to the impeller side of the mechanical seal. the bearing is attached to a bearing casing fixed within the pump casing;
The protective tube is connected to the second end side end of the rotating shaft in the bearing casing via a fastening connection part,
The self-water injection mechanism includes a third pipe having a first end connected to the discharge section and a second end disposed at the connection section.
The pump according to claim 2. The mechanical seal includes a first seal portion that seals the impeller side, a second seal portion that seals the bearing side , and a housing that accommodates these ,
The housing has a first injection hole to which the second piping of the self-water injection mechanism is connected in correspondence with the first seal part , and a first injection hole to which the external water injection mechanism is connected in correspondence to the second seal part. A second injection hole is provided .
The pump according to claim 2 or 3. The pump according to claim 4, wherein the external water injection mechanism includes a fourth pipe having a first end connected to the water source and a second end connected to the second injection hole . The self-water injection mechanism includes a fifth pipe having a first end connected to the discharge part and a second end connected to the fourth pipe,
The connection part between the fourth pipe and the fifth pipe is provided with a switching part that switches the connection state so that one of the fourth pipe and the fifth pipe is connected to the second seal part.
The pump according to claim 5. a circulation pipe that is disposed outside the pump casing and communicates the first end side and the second end side of the rotating shaft in the lubricant flow path;
The pump according to any one of claims 1 to 6, further comprising: a delivery section that causes the lubricant to flow from the second end side to the first end side of the rotating shaft in the lubricant flow path.

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