JP7650677B2 - Vertical Pump - Google Patents

Description

The present invention relates to a vertical pump.

The vertical pump described in Patent Document 1 below has been known for some time. The vertical pump includes a rotating shaft extending vertically, an impeller fixed to the rotating shaft, a cylindrical casing that houses the impeller, a bracket having a lid that closes the upper opening of the casing and a through hole through which the rotating shaft is inserted in the lid, and a mechanical seal that seals between the rotating shaft and the through hole. The mechanical seal has a fixed part fixed to the bracket and a rotating part fixed to the rotating shaft, and seals the periphery of the rotating shaft with the sliding surface between the fixed part and the rotating part as a seal surface.

JP 2008-75476 A

In conventional vertical pumps, the sliding surface of the mechanical seal is located inside the casing and exposed to the handled liquid (see reference numeral 11 in Figure 1 of Patent Document 1). Vertical pumps are sometimes used in high-temperature, high-pressure environments, such as in boilers, and in such cases, the sliding surface of the mechanical seal is prone to running dry. When the pump runs dry, the sliding surface wears, the handled liquid seeps out due to the wear, and the sliding surface is stabilized (sealing ability is restored) due to the seepage of the handled liquid. This cycle of sliding surface wear shortens the life of the mechanical seal, and there is a problem in that maintenance such as replacement and repair becomes more frequent.

The present invention was made in consideration of the above problems, and aims to provide a vertical pump that can prevent the sliding surface of the mechanical seal from running dry, even when used in a high-temperature, high-pressure environment.

The vertical pump according to one aspect of the present invention comprises a rotating shaft extending vertically, an impeller fixed to the rotating shaft, a cylindrical casing housing the impeller, a lid that closes the upper opening of the casing, a bracket that protrudes upward from the lid and has a cylindrical portion through which the rotating shaft is inserted, and a mechanical seal that seals the gap between the rotating shaft and the cylindrical portion, and the sliding surface of the mechanical seal is located inside the cylindrical portion.

In the vertical pump, the cylindrical portion may be provided with an air vent valve at a position equal to or higher than the height of the sliding surface of the mechanical seal.

The vertical pump may be provided with a pumped liquid circulation structure that forms a circulating flow that guides the pumped liquid inside the casing to the sliding surface of the mechanical seal inside the cylindrical portion.

In the vertical pump, the handled liquid circulation structure may include an inner cylinder member disposed inside the cylindrical portion and surrounding the outside of the sliding surface of the mechanical seal, and a second impeller fixed to the rotating shaft and forming the circulating flow with either the inside or the outside of the inner cylinder member as the forward path and the other as the return path.

In the vertical pump, the inner cylinder member may be fixed to the bracket.

In the vertical pump, the inner cylinder member may be fixed to the second impeller and rotate together with the second impeller.

In the vertical pump, the second impeller may form the circulation flow with the outside of the inner cylinder member as the outward path and the inside of the inner cylinder member as the return path.

The vertical pump may also include a third impeller that is fixed to the rotating shaft and air-cools the cylindrical portion from the outside.

According to one aspect of the present invention, a vertical pump can be provided that can prevent the sliding surface of the mechanical seal from running dry, even when used in a high-temperature, high-pressure environment.

FIG. 2 is a cross-sectional view of the vertical pump according to the first embodiment. 2 is a cross-sectional view of the vicinity of a cylindrical portion of the vertical pump according to the first embodiment. FIG. FIG. 4 is a plan view of a second impeller according to the first embodiment. FIG. 2 is a cross-sectional view of an inner cylinder member according to the first embodiment. FIG. 2 is a plan view of the inner cylinder member according to the first embodiment. FIG. 11 is a cross-sectional view of the vicinity of a cylindrical portion of a vertical pump according to a second embodiment. FIG. 6 is a cross-sectional view of a handled fluid circulation structure according to a second embodiment. FIG. 11 is a plan view of a handled fluid circulation structure according to a second embodiment. FIG. 11 is a cross-sectional view of the vicinity of a cylindrical portion of a vertical pump according to a third embodiment. FIG. 11 is a cross-sectional view of the vicinity of a cylindrical portion of a vertical pump according to a fourth embodiment. FIG. 13 is a plan view of a handled fluid circulation structure according to a fourth embodiment. FIG. 13 is a cross-sectional view of the vicinity of a cylindrical portion of a vertical pump according to a fifth embodiment. FIG. 13 is a plan view showing a third impeller according to a fifth embodiment.

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

First Embodiment
FIG. 1 is a cross-sectional view of a vertical pump 1 according to a first embodiment.
1 is a vertical multi-stage pump including a rotating shaft 2 extending in the vertical direction and a plurality of impellers 3 fixed to the rotating shaft 2. In the following, the configuration of this vertical multi-stage pump will be described, but it may be in a form having only one impeller 3. In addition, in the following description, the direction in which the central axis O of the rotating shaft 2 extends is referred to as the axial direction, the direction perpendicular to the central axis O is referred to as the radial direction, and the direction rotating around the central axis O is referred to as the circumferential direction.

The impeller 3 has a main plate 4, a side plate 5, and a number of blades 6. The main plate 4 is formed in a disk shape centered on the central axis O, and is fixed to the rotating shaft 2. The side plate 5 is formed in an annular shape coaxial with the main plate 4, and is disposed with a gap between it and the main plate 4 in the axial direction. The main plate 4 and the side plate 5 are connected via a number of blades 6. The space surrounded by the main plate 4, the side plate 5, and the number of blades 6 forms a flow path that guides the handled liquid in the radial direction. The side plate 5 forms the suction port 7 of the impeller 3.

The vertical pump 1 has a cylindrical casing 11 that houses the impeller 3. The casing 11 has a pump chamber 10A formed inside, in which the pumped liquid is pressurized by the impeller 3. The casing 11 has an intermediate casing 11a stacked in multiple stages, an upper casing 11b arranged on the upper part of the intermediate casing 11a, a lower casing 11c arranged on the lower part of the intermediate casing 11a, and an outer casing 11d arranged on the outside of the intermediate casing 11a and the upper casing 11b.

The intermediate casing 11a is formed into a bottomed cylinder by pressing a steel plate or the like, and an opening is formed in the center of the bottom through which the rotating shaft 2 is inserted. The intermediate casings 11a are stacked in multiple stages according to the number of impellers 3. A return plate 12 is attached by welding to the underside of the bottom of the intermediate casing 11a. In addition, return vanes 13 are attached by welding to the underside of the return plate 12. A liner ring 14 is attached to the inner wall of the bottom opening of the intermediate casing 11a to prevent leakage of the handled liquid from around the suction port 7 of the impeller 3.

The upper casing 11b is formed in a cylindrical shape with a bottom like the intermediate casing 11a, and is stacked on the top of the intermediate casing 11a. A plurality of communication holes 11b1 are formed in the peripheral wall of the upper casing 11b. The outer casing 11d is formed in a cylindrical shape that surrounds the radial outside of the intermediate casing 11a and the upper casing 11b. The outer casing 11d forms an annular flow path 10B that communicates with the communication holes 11b1 on the radial outside of the intermediate casing 11a and the upper casing 11b. The upper parts of the upper casing 11b and the outer casing 11d are covered by a casing cover 11e arranged on the underside of the bracket 31.

The lower casing 11c forms a communication space 10C that communicates with the suction port 7 at the lower end of the pump chamber 10A, and also forms a communication space 10D (second communication space) that communicates with the above-mentioned annular flow path 10B inside the outer casing 11d. The lower casing 11c has a first frame 11c1 that forms the communication space 10C on the inside, and a second frame 11c2 that surrounds the outside of the first frame 11c1 and forms the communication space 10D between itself and the first frame 11c1.

The first frame 11c1 is formed in a bottomed cylindrical shape (approximately dish-shaped) with a flange 11c4 in which a communication hole 11c3 is formed. The communication hole 11c3 penetrates the flange 11c4 in the axial direction, and connects the annular flow path 10B to the communication space 10D. The second frame 11c2 is formed in a bottomed cylindrical shape that accommodates the first frame 11c1 in a nested manner. The outer edge of the flange 11c4 of the first frame 11c1 contacts the inner peripheral surface of the second frame 11c2, forming a gap (communication space 10D) between the outer peripheral surface of the first frame 11c1 and the inner peripheral surface of the second frame 11c2.

The lower casing 11c has a suction nozzle 21 that extends horizontally and a discharge nozzle 22 that also extends horizontally. The suction nozzle 21 penetrates and is joined to the peripheral wall of the second frame 11c2, penetrates and is joined to the peripheral wall of the first frame 11c1, and extends to the communication space 10C. The discharge nozzle 22 is disposed in the same straight line as the suction nozzle 21, penetrates and is joined to the peripheral wall of the second frame 11c2, does not penetrate the peripheral wall of the first frame 11c1, and is connected to the communication space 10D.

A pump stand 23 is provided below the lower casing 11c. The pump stand 23 is axially connected to the bracket 31 by casing bolts 23a and nuts 23b. A plurality of casing bolts 23a and nuts 23b are provided at intervals in the circumferential direction. By fastening the plurality of casing bolts 23a and nuts 23b, the multiple stages of the intermediate casing 11a, upper casing 11b, lower casing 11c, and casing cover 11e are clamped in the axial direction.

The bracket 31 has a lid 32 that closes the upper opening of the casing 11, and a tube 33 that protrudes upward from the lid 32 and through which the rotating shaft 2 is inserted. The bracket 31 also has a pair of legs 34 (the legs 34 on the near side in FIG. 1 are not shown) that are disposed radially outward from the tube 33 and protrude upward from the lid 32, and a base 35 that is supported by the pair of legs 34.

The base 35 supports a motor (not shown). The output shaft of the motor (not shown) is connected to the upper end of the rotating shaft 2 protruding upward from the cylindrical portion 33 via a coupling (not shown). The coupling (not shown) is surrounded by a pair of guard members 36 that are screwed to a pair of legs 34.

An air vent valve 37 and a priming valve 38 are provided radially outward of the tubular portion 33 of the lid portion 32. An air vent valve 39 (second air vent valve) is also provided on the tubular portion 33. A mechanical seal 40 is attached to the tubular portion 33. The mechanical seal 40 seals the gap between the rotating shaft 2 and the tubular portion 33, and prevents the pumped fluid from leaking from the pump chamber 10A through the tubular portion 33 to the outside of the machine.

In the vertical pump 1 configured as described above, when the impeller 3 rotates, the handled liquid is sucked into the communication space 10C of the lower casing 11c through the suction nozzle 21. The handled liquid sucked into the communication space 10C is sucked into the first-stage impeller 3 through the suction port 7 at the lower end of the pump chamber 10A and pressurized. The handled liquid discharged from the first-stage impeller 3 passes through a flow path formed by the return vanes 13 and the return plate 12 and is guided to the suction port 7 of the next-stage impeller 3.

The handled liquid is pressurized in multiple stages by the multiple impellers 3 and then flows into the upper casing 11b. The handled liquid that flows into the upper casing 11b flows down through the annular flow passage 10B formed on the outside of the upper casing 11b from the communication hole 11b1 and flows into the communication space 10D through the communication hole 11c3. The handled liquid that flows into the communication space 10D is discharged through the discharge nozzle 22 connected to the lower casing 11c.

FIG. 2 is a cross-sectional view of the vicinity of the cylindrical portion 33 of the vertical pump 1 according to the first embodiment.
2, the mechanical seal 40 is attached to the cylindrical portion 33 of the bracket 31. The mechanical seal 40 has a fixed portion 41 fixed to the bracket 31 side, and a rotating portion 42 fixed to the rotating shaft 2 side. Note that the mechanical seal 40 in this embodiment is a cartridge type in which the fixed portion 41 and the rotating portion 42 are detachable together, but it does not have to be of the cartridge type.

The fixed part 41 includes a fixed ring 43 (sliding member) that forms a sliding surface 40a that seals the periphery of the rotating shaft 2, and a holder 44 that holds the fixed ring 43. The sliding surface 40a is formed on the lower end surface of the fixed ring 43. The outer peripheral surface of the fixed ring 43 is formed with a step on which an O-ring 45 is disposed. This O-ring 45 provides a seal between the fixed ring 43 and the holder 44.

The holder 44 surrounds the outer peripheral surface of the fixed ring 43 and restricts the upward axial movement of the fixed ring 43 via an O-ring 45. The holder 44 has a bottom 44a with an opening, a side wall 44b extending upward from the peripheral edge of the bottom 44a, and a flange 44c extending radially outward from the upper end of the side wall 44b.

The rotating shaft 2 and sleeve 49 (described later) are inserted through the opening of the bottom 44a with a gap therebetween. The fixed ring 43 is held on the inner wall surface of the opening of the bottom 44a. The side wall 44b is an annular wall that extends from the periphery of the bottom 44a to the upper end of the tubular portion 33. An annular groove is formed on the outer wall surface of the side wall 44b in which an O-ring 45 is placed to seal the gap with the casing cover 11e that extends to the inner wall surface of the tubular portion 33.

The flange 44c is formed in an annular shape extending radially outward from the upper end of the side wall 44b. The flange 44c contacts the peripheral edge of the upper opening of the tubular portion 33. The flange 44c is fixed to the tubular portion 33 in the axial direction by bolts 46 (fixing part fixing components). Multiple bolts 46 are provided at intervals in the circumferential direction, and fix the flange 44c to the tubular portion 33 at multiple points.

The rotating part 42 has a rotating ring 47 (the mating sliding member) that faces the fixed ring 43 and forms the sliding surface 40a, a sleeve 49 that supports the rotating ring 47 on its outer periphery via a holder 48, a spring 50, and a second impeller 62 (described later) and through which the rotating shaft 2 is inserted on its inner periphery, and a sleeve retainer 51 that fixes the sleeve 49 to the rotating shaft 2. The upper end surface of the rotating ring 47 that faces the fixed ring 43 in the axial direction forms the sliding surface 40a.

The gaps between the rotating ring 47 and the holder 48, between the holder 48 and the sleeve 49, and between the sleeve 49 and the rotating shaft 2 are sealed with O-rings 45. The holder 48 surrounds the outer circumferential surface of the rotating ring 47 and supports the rotating ring 47 from below via the O-ring 45. The spring 50 biases the holder 48 upward, pressing the rotating ring 47 towards the fixed ring 43.

The sleeve 49 is formed in a cylindrical shape and is fitted to the rotating shaft 2. The lower end of the sleeve 49 expands radially outward, and the upper surface of the expanded diameter portion supports the second impeller 62. The spring 50 is disposed in the axial gap between the holder 48 and the second impeller 62, and biases the holder 48 upward and presses the second impeller 62 against the expanded diameter portion of the sleeve 49 to fix it.

The lower end surface of the sleeve 49 is in axial contact with a ring retainer 2a fixed to the rotating shaft 2. The ring retainer 2a is a shaft part that determines the axial position of the mechanical seal 40. On the inside of the ring retainer 2a, a split ring 2b that determines the axial position of the ring retainer 2a is attached to an annular groove formed on the rotating shaft 2. This sleeve 49 passes through the inside of the rotating ring 47 and the fixed ring 43, and extends from the pump chamber 10A (inside the machine) to outside the machine.

The sleeve retainer 51 is welded to the upper end of the sleeve 49. The sleeve retainer 51 is formed in an annular shape, and multiple set screws 52 (rotating part fixing parts) are screwed into it at intervals in the circumferential direction. The sleeve 49 has through holes at positions corresponding to the set screws 52, and the rotating shaft 2 can be tightened in the radial direction by screwing in the set screws 52. This fixes the rotating part 42 to the rotating shaft 2, and the rotating part 42 can rotate together with the rotating shaft 2.

The sliding surface 40a of the mechanical seal 40 is located inside the tubular portion 33. That is, the sliding surface 40a of the mechanical seal 40 is located higher than the casing 11 (pump chamber 10A). The tubular portion 33 is provided with a second air vent plug 39 at a position equal to or higher than the height of the sliding surface 40a of the mechanical seal 40. Since the second air vent plug 39 is located at a position equal to or higher than the height of the sliding surface 40a of the mechanical seal 40, priming water can be injected up to the sliding surface 40a of the mechanical seal 40.

The vertical pump 1 is provided with a handled fluid circulation structure 60 that forms a circulation flow (indicated by an arrow in FIG. 2) that guides the handled fluid inside the casing 11 (pump chamber 10A) to the sliding surface 40a of the mechanical seal 40 inside the cylindrical portion 33 during operation. The handled fluid circulation structure 60 is provided with an inner cylindrical member 61 that is disposed inside the cylindrical portion 33 and surrounds the outside of the sliding surface 40a of the mechanical seal 40, and a second impeller 62 that is fixed to the rotating shaft 2 and forms a circulation flow with either the inside or the outside of the inner cylindrical member 61 (the inside in FIG. 2) as the forward path and the other (the outside in FIG. 2) as the return path.

Fig. 3 is a plan view of the second impeller 62 according to the first embodiment. Fig. 4 is a cross-sectional view of the inner cylinder member 61 according to the first embodiment. Fig. 5 is a plan view of the inner cylinder member 61 according to the first embodiment.
As shown in FIG. 3, the second impeller 62 includes a cylindrical mounting tube portion 62a and a plurality of blades 62b provided on the outer circumferential surface of the mounting tube portion 62a.

As shown in FIG. 2, the mounting cylinder portion 62a is fitted onto the sleeve 49. The blades 62b have the blade shape of an axial fan, and send the handled liquid from the pump chamber 10A toward the inside of the inner cylinder member 61. Note that, for example, the second impeller 62 may be a centrifugal fan instead of an axial fan, as long as it can eventually form the circulating flow shown in FIG. 2.

As shown in FIG. 4, the inner tube member 61 is formed in a cylindrical shape and has an annular flange 61a extending radially outward at its lower end. As shown in FIG. 5, the flange 61a has a plurality of holes 61b formed at intervals in the circumferential direction. The holes 61b are formed in an arc shape along the outer circumferential surface of the inner tube member 61.

The inner cylinder member 61 is fixed to the bracket 31 as shown in FIG. 2. The casing cover 11e that forms the inner wall surface of the bracket 31 has an annular groove 11e1 recessed radially outward. The outer peripheral end of the flange 61a of the inner cylinder member 61 fits into the annular groove 11e1 of the casing cover 11e.

The flange 61a is formed with a hole 61b that penetrates in the axial direction, so that the handled fluid flowing outside the inner cylinder member 61 can pass through the flange 61a. The hole 61b may be a cutout that is cut out to the outer circumferential edge of the flange 61a. In this embodiment, the outer circumferential edge of the flange 61a is not cut out, so that the contact area with the annular groove 11e1 is secured all around, and the stability of the attachment of the inner cylinder member 61 is improved.

The inner diameter of the inner cylinder member 61 is larger than the outer diameter of the rotating portion 42 of the mechanical seal 40. The outer diameter of the inner cylinder member 61 is smaller than the inner diameter of the casing cover 11e that forms the inner wall surface of the cylindrical portion 33. This inner cylinder member 61 extends in the axial direction from a position near the base of the cylindrical portion 33 to a position equal to or higher than the height of the sliding surface 40a of the mechanical seal 40. An axial gap is formed between the upper end of the inner cylinder member 61 and the fixed portion 41 of the mechanical seal 40.

The following describes the wear loop that occurs when the sliding surface 40a of the mechanical seal 40 configured as above is in a dry operating state. In high-temperature, high-pressure environments such as those used in boilers, the sliding surface 40a of the mechanical seal 40 is prone to falling into a dry operating state, and this causes a cycle of wear of the sliding surface 40a, leakage of liquid due to wear, and stabilization of the sliding surface 40a due to leakage of liquid (restoration of sealing properties).

Specifically, when the sliding surface 40a of the mechanical seal 40 is in a dry operating state, or when external factors such as pressure fluctuations are added, the mechanical seal 40 comes into contact with one side of the sliding surface 40a, causing it to wear at a faster pace than usual. As a result, as wear progresses, liquid begins to seep out from the sliding surface 40a, and if this condition continues, the liquid leakage will be fortunate enough to provide sufficient water lubrication. Furthermore, the wear marks on the sliding surface 40a will act as an abrasive, trying to keep the sliding surface 40a in a stable state. This will reduce the amount of liquid leakage, and the process will loop back to the first step.

As shown in FIG. 1, the vertical pump 1 of this embodiment includes a rotating shaft 2 extending vertically, an impeller 3 fixed to the rotating shaft 2, a cylindrical casing 11 housing the impeller 3, a lid 32 closing the upper opening of the casing 11, a bracket 31 protruding upward from the lid 32 and having a cylindrical portion 33 through which the rotating shaft 2 is inserted, and a mechanical seal 40 sealing the gap between the rotating shaft 2 and the cylindrical portion 33, and the sliding surface 40a of the mechanical seal 40 is located inside the cylindrical portion 33. With this configuration, the sliding surface 40a of the mechanical seal 40 is located higher than the pump chamber 10A, and the handled liquid in the pump chamber 10A is not supplied to the sliding surface 40a while still in a high-temperature and high-pressure state. Therefore, the dry operation state of the sliding surface 40a of the mechanical seal 40 can be suppressed. This reduces the frequency of maintenance of the mechanical seal 40.

In addition, in this embodiment, the cylindrical portion 33 is provided with a second air vent valve 39 at a position equal to or higher than the height of the sliding surface 40a of the mechanical seal 40. With this configuration, priming water can be injected up to the sliding surface 40a of the mechanical seal 40 arranged inside the cylindrical portion 33. Note that the air vent valve 37 provided on the lid portion 32 shown in FIG. 1 may be eliminated and unified with the second air vent valve 39, but the presence of the air vent valve 37 on the lid portion 32 shortens the time required to fill the pump chamber 10A with priming water.

In addition, as shown in FIG. 2, this embodiment is provided with a handled fluid circulation structure 60 that forms a circulating flow that guides the handled fluid inside the casing 11 to the sliding surface 40a of the mechanical seal 40 inside the cylindrical portion 33. With this configuration, new handled fluid can always be supplied to the sliding surface 40a of the mechanical seal 40 located inside the cylindrical portion 33, so that the sliding surface 40a can be prevented from running dry. In addition, since the cylindrical portion 33 protrudes from the lid portion 32 and has a large contact area with the outside air, the handled fluid is cooled as it passes through the inside of the cylindrical portion 33. As a result, the sliding surface 40a of the mechanical seal 40 is cooled by the handled fluid, making it difficult for the sliding surface 40a to run dry.

In this embodiment, the handled fluid circulation structure 60 includes an inner cylinder member 61 that is disposed inside the cylinder portion 33 and surrounds the outside of the sliding surface 40a of the mechanical seal 40, and a second impeller 62 that is fixed to the rotating shaft 2 and forms a circulating flow with the inside of the inner cylinder member 61 as the outgoing path and the outside as the return path. With this configuration, by disposing the inner cylinder member 61 inside the cylinder portion 33 and sending the handled fluid inside the inner cylinder member 61 with the second impeller 62, a circulating flow can be formed in the narrow gap between the cylinder portion 33 and the mechanical seal 40.

In addition, in this embodiment, the inner tube member 61 is fixed to the bracket 31. This configuration can increase the stability of the attachment of the inner tube member 61.

Second Embodiment
Next, a second embodiment of the present invention will be described. In the following description, the same or equivalent components as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof will be simplified or omitted.

FIG. 6 is a cross-sectional view of the vicinity of a cylindrical portion 33 of a vertical pump 1 according to a second embodiment.
As shown in FIG. 6 , the vertical pump 1 of the second embodiment includes a pumped liquid circulation structure 60 in which an inner cylindrical member 61 is fixed to a second impeller 62 and rotates together with the second impeller 62 .

Fig. 7 is a cross-sectional view of the treated fluid circulation structure 60 according to the second embodiment. Fig. 8 is a plan view of the treated fluid circulation structure 60 according to the second embodiment.
7 and 8, the flange 61a (see FIGS. 2 and 4) is not provided on the inner cylinder member 61. The lower end of the inner cylinder member 61 is joined to the radially outer ends of the blades 62b of the second impeller 62. The handled liquid passes through the gaps between the blades 62b and passes through the inside of the inner cylinder member 61.

According to the second embodiment having the above configuration, a circulating flow is formed in the same manner as in the first embodiment, and the dry operation state of the sliding surface 40a of the mechanical seal 40 can be suppressed. Also, in the second embodiment, the inner cylinder member 61 is fixed to the second impeller 62 and rotates together with the second impeller 62, so there is no need to form an annular groove 11e1 or the like on the bracket 31 side. Furthermore, by integrating the inner cylinder member 61 and the second impeller 62, the number of parts of the handled liquid circulation structure 60 is reduced, making assembly easier.

Third Embodiment
Next, a third embodiment of the present invention will be described. In the following description, the same or equivalent components as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof will be simplified or omitted.

FIG. 9 is a cross-sectional view of the vicinity of a cylindrical portion 33 of a vertical pump 1 according to a third embodiment.
As shown in FIG. 9 , in the vertical pump 1 of the third embodiment, a circulation flow is formed in which the outside of the inner cylindrical member 61 is the forward path and the inside of the inner cylindrical member 61 is the return path as a result of the rotation of the second impeller 62.

The second impeller 62 of the third embodiment is an axial fan similar to that of the first embodiment described above, but its orientation is upside down compared to the second impeller 62 of the first embodiment (see FIG. 2 described above). This allows the handled liquid inside the inner cylinder member 61 to be sent to the pump chamber 10A. This allows the handled liquid to be sucked to the outside of the inner cylinder member 61, forming a circulating flow with the outside of the inner cylinder member 61 as the outgoing path and the inside of the inner cylinder member 61 as the return path.

According to the third embodiment having the above configuration, the outside of the inner cylinder member 61 close to the cylinder portion 33, which is air-cooled by contact with the outside air, becomes the outgoing path of the circulation flow, so the temperature of the handled fluid can be further lowered before it reaches the sliding surface 40a of the mechanical seal 40. This increases the effect of suppressing the dry operation state of the sliding surface 40a of the mechanical seal 40.

Fourth Embodiment
Next, a fourth embodiment of the present invention will be described. In the following description, the same or equivalent components as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof will be simplified or omitted.

FIG. 10 is a cross-sectional view of the vicinity of a cylindrical portion 33 of a vertical pump 1 according to a fourth embodiment.
As shown in FIG. 10 , in the vertical pump 1 of the fourth embodiment, as the second impeller 62 rotates, a circulation flow is formed with the outside of the inner cylinder member 61 as the forward path and the inside of the inner cylinder member 61 as the return path, and the inner cylinder member 61 is fixed to the second impeller 62 and rotates together with the second impeller 62.

FIG. 11 is a plan view of a handled fluid circulation structure 60 according to the fourth embodiment.
11, the inner tubular member 61 is joined to the radially outer ends of the multiple blades 62b of the second impeller 62. The blades 62b of the fourth embodiment are circumferentially oriented in the opposite direction to the blades 62b of the second embodiment (see FIG. 8), so that the pumped fluid inside the inner tubular member 61 can be sent to the pump chamber 10A.

According to the fourth embodiment having the above configuration, as in the second embodiment, the inner cylinder member 61 is fixed to the second impeller 62 and rotates together with the second impeller 62, so there is no need to form a fixing structure such as annular groove 11e1 on the bracket 31 side. Furthermore, by integrating the inner cylinder member 61 and the second impeller 62, the number of parts of the handled liquid circulation structure 60 is reduced, making assembly easier. Also, according to the fourth embodiment, as in the third embodiment, the outside of the inner cylinder member 61 becomes the outgoing path of the circulating flow, so that the temperature of the handled liquid is lowered, making it easier to cool the sliding surface 40a of the mechanical seal 40.

Fifth Embodiment
Next, a fifth embodiment of the present invention will be described. In the following description, the same or equivalent components as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof will be simplified or omitted.

FIG. 12 is a cross-sectional view of the vicinity of a cylindrical portion 33 of a vertical pump 1 according to a fifth embodiment.
As shown in FIG. 12, the vertical pump 1 of the fifth embodiment is provided with a third impeller 70 that is fixed to the rotary shaft 2 and air-cools the cylindrical portion 33 from the outside.

The third impeller 70 rotates with the rotating shaft 2, and generates cooling air (indicated by arrows in FIG. 12) toward the inside and outside of the tubular portion 33. In this embodiment, the third impeller 70 is attached by spot welding to the upper surface of the sleeve retainer 51 that fixes the sleeve 49 to the rotating shaft 2. Note that the third impeller 70 may be attached to the sleeve 49, for example, or directly to the rotating shaft 2, as long as it can rotate with the rotating shaft 2.

FIG. 13 is a plan view showing a third impeller 70 according to the fifth embodiment.
The third impeller 70 has a ring portion 71 with an opening 71a formed in the center, and a plurality of blade portions 72 extending radially outward from the ring portion 71. The ring portion 71 is formed in a flat plate shape. The opening 71a of the ring portion 71 has a size that allows the rotating shaft 2 to be inserted therethrough. The ring portion 71 has a plurality of joint portions 71b joined to the sleeve holder 51 by spot welding, which are formed at intervals in the circumferential direction. In this embodiment, the joint portions 71b and the blade portions 72 are in phase with each other in the circumferential direction, but they do not have to be in phase with each other.

The third impeller 70 is attached to the sleeve holder 51 so as to rotate clockwise in the plan view shown in FIG. 13. The blade portion 72 has a flat front edge portion 72a extending radially outward from the outer periphery of the ring portion 71, and a rear edge portion 72b extending diagonally downward from the front edge portion 72a toward the rear side in the rotation direction. As shown in FIG. 12, the rear edge portion 72b is disposed radially outward from the sleeve holder 51 so as not to interfere with the sleeve holder 51. In addition, the lower end portion of the rear edge portion 72b is located above the head portion of the bolt 46 so as not to interfere with the bolt 46.

According to the fifth embodiment having the above configuration, as shown in FIG. 12, when the rotating shaft 2 rotates, the third impeller 70 rotates, and cooling air is generated toward the inside and outside of the cylindrical portion 33. The cooling air toward the inside of the cylindrical portion 33 hits the holder 44 and indirectly cools the stationary ring 43 forming the sliding surface 40a by heat conduction through the holder 44. In addition, the cooling air toward the outside of the cylindrical portion 33 flows along the outer wall surface of the cylindrical portion 33, and by cooling the cylindrical portion 33, indirectly cools the handled fluid flowing outside the inner cylindrical member 61. This effectively cools the sliding surface 40a of the mechanical seal 40, and more reliably suppresses the dry operation state.

Although preferred embodiments of the present invention have been described and illustrated above, it should be understood that these are illustrative of the present invention and should not be considered as limiting. Additions, omissions, substitutions, and other modifications can be made without departing from the scope of the present invention. Thus, the present invention should not be considered as limited by the foregoing description, but rather by the scope of the claims.

1 ... vertical pump, 2 ... rotating shaft, 2b ... ring, 3 ... impeller, 4 ... main plate, 5 ... side plate, 6 ... blade, 7 ... suction port, 10A ... pump chamber, 10B ... annular flow passage, 10C ... communication space, 10D ... communication space, 11 ... casing, 11a ... intermediate casing, 11b ... upper casing, 11b1 ... communication hole, 11c ... lower casing, 11c1 ... first frame, 11c2 ... second frame, 11c3 ... communication hole, 11c4 ... flange, 11d ... outer casing, 11e ... casing cover, 11e1 ... annular groove, 12 ... return plate, 13 ... return vane, 14 ... liner ring, 21 ... suction nozzle, 22 ... discharge nozzle, 23 ... pump stand, 23a ... casing bolt, 23b ... nut, 30A ... pump chamber, 31 ... bracket, 32 ... cover, 3 Reference Signs List 3: Cylinder portion, 34: Leg portion, 35: Base portion, 36: Guard member, 37: Air vent plug, 38: Priming plug, 39: Second air vent plug (air vent plug), 40: Mechanical seal, 40a: Sliding surface, 41: Fixed portion, 42: Rotating portion, 43: Fixed ring, 44: Holder, 44a: Bottom portion, 44b: Side wall portion, 44c: Flange portion, 45: O-ring, 46: Bolt, 47: Rotating ring, 48 ...Holder, 49...Sleeve, 50...Spring, 52...Set screw, 60...Treatment liquid circulation structure, 61...Inner cylinder member, 61a...Flange, 61b...Hole, 62...Second impeller, 62a...Mounting cylinder, 62b...Blade, 70...Third impeller, 71...Ring, 71a...Opening, 71b...Joint, 72...Blade, 72a...Front edge, 72b...Rear edge, O...Center axis

Claims (5)

A rotation axis extending in a vertical direction;
An impeller fixed to the rotating shaft;
A cylindrical casing that houses the impeller;
a bracket having a lid portion that closes an upper opening of the casing, and a tubular portion that protrudes upward from the lid portion and through which the rotating shaft is inserted;
a mechanical seal that seals a gap between the rotating shaft and the cylindrical portion,
The sliding surface of the mechanical seal is located inside the cylindrical portion ,
The vertical pump , wherein the cylindrical portion is provided with an air vent plug at a position equal to or higher than the height of the sliding surface of the mechanical seal . a handled fluid circulation structure that forms a circulating flow that guides the handled fluid inside the casing to the sliding surface of the mechanical seal inside the cylindrical portion ,
The handled liquid circulation structure includes:
2. The vertical pump according to claim 1, further comprising: an inner cylindrical member disposed inside the cylindrical portion and surrounding an outside of a sliding surface of the mechanical seal ; and a second impeller fixed to the rotating shaft and forming the circulating flow with the outside of the inner cylindrical member as an outward path and the inside of the inner cylindrical member as a return path . 3. The vertical pump according to claim 2 , wherein the inner cylindrical member is fixed to the bracket. 3. The vertical pump according to claim 2 , wherein the inner cylindrical member is fixed to the second impeller and rotates together with the second impeller. 5. The vertical pump according to claim 1, further comprising a third impeller fixed to the rotating shaft for air-cooling the cylindrical portion from the outside.

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