JP4078833B2 - Double suction centrifugal pump - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a double suction centrifugal pump in which a double suction type impeller is fixed to a rotary shaft arranged in a substantially horizontal direction.
[0002]
[Prior art]
In general, as shown in FIG. 1, both suction centrifugal pumps 21 are constructed as shown in FIG. 1 (for example, see FIG. 1 of JIS B 8322, FIG. 1 of JP-A-7-318449, FIG. 1 of JP-A-8-28486, FIG. A rotating shaft (main shaft) 22 arranged in a substantially horizontal direction (shown in FIG. 1 of Japanese Patent Laid-Open No. 11-236894, FIG. 1 of Japanese Patent Laid-Open No. 11-303789, etc.), and fixed to the rotating shaft 22, A double-suction centrifugal impeller 23 that allows fluid to flow in from both sides in the axial direction and flow out to the radially outer peripheral side in the axially intermediate portion, and a spiral casing 24 provided so as to contain the impeller 23; A bearing housing 25 provided on both ends in the axial direction outside the spiral casing 24, and a bearing portion 26 (rolling bearing) provided inside the bearing housing 25 and lubricated with grease or oil. And a sliding bearing) is.
[0003]
When the rotary shaft 22 is thus supported by the bearing portions 26 provided on both ends in the axial direction outside the spiral casing 24, the support spans between the bearing portions 26 (from the support position of one bearing portion 26 to the other bearing portion 26). The distance to the support position) tended to be longer.
[0004]
Therefore, in order to cope with this, as shown in FIG. 3 of Japanese Patent Application Laid-Open No. 2000-124070, for example, the self-fluid is handled by providing a bearing portion made of a resin material at the rotating shaft penetrating portion (two places on both sides) of the spiral casing. A structure in which the bearing is lubricated is proposed.
[0005]
[Problems to be solved by the invention]
According to the above prior art, the bearing span can be shortened as compared with the case where the rotating shaft is supported by the bearing portion provided outside the spiral casing. As a result, the diameter of the rotating shaft to which the impeller is attached (specifically, the central portion to which the impeller is attached) is reduced by the amount that can reduce the bending stress generated on the rotating shaft during pump operation, and the suction characteristics of the impeller are improved. The pump performance can be improved.
[0006]
However, in the above-described prior art, since the bearing portions on both sides in the axial direction are provided in the both-side through portions of the spiral casing, there is a limit to shortening the bearing span. In order to cope with the operation (especially at the time of start-up in which no water film is formed), the bearing portion needs to be supplied with water. For this reason, it is difficult to further improve the pump performance and simplify the equipment, leaving room for improvement.
[0007]
An object of the present invention is to provide a double suction centrifugal pump that can significantly reduce the bearing span and sufficiently improve the pump performance.
[0013]
[Means for Solving the Problems]
(1) In order to achieve the above-mentioned object , the present invention provides a rotating shaft arranged in a substantially horizontal direction, fixed to the rotating shaft, and fluid from the connecting side to the driving means of the rotating shaft and the anti-connecting side. And a suction centrifugal impeller that causes the fluid to flow out radially outward at an intermediate portion between the connection side and the anti-connection side, and a spiral casing provided so as to contain the impeller In both the suction centrifugal pumps having the above, bearing portions for rotatably supporting the impeller are provided on both of the mouth ring portions on the connection side and the anti-connection side.
[0014]
As a result, since the support position is changed from the penetrating portion (casing wall surface position) to the inside of the casing on both the drive means connecting side and the anti-connecting side, the support span between the bearing portions can be further reduced.
[0015]
( 2 ) In the above ( 1 ), preferably, the bearing portions provided on both of the mouth ring portions on the connection side and the anti-connection side receive only a radial load.
[0016]
( 3 ) In the above ( 1 ), preferably, the bearing portions provided on both the mouth ring portions on the connection side and the anti-connection side receive both a radial load and a thrust load.
[0017]
( 4 ) In the above (3) , preferably, the diameter of the anti-connection side of the mouth ring portions on the connection side and the anti-connection side is made smaller than the diameter of the connection side.
[0018]
Diameter of mouth ring portion of the anti-connection side, smaller diameter to highlight an optimal that improves pump performance diameter (mouth ring diameter in other words), via a reduction and mouth ring relative velocity at the blade inlet of the working fluid Pump performance can be further improved by reducing the amount of leakage from the high pressure part (discharge side) to the low pressure part (suction side).
[0019]
( 5 ) In any one of the above (1) to ( 4 ), preferably, the bearing portion is a slide bearing provided with a sliding portion made of a resin member.
[0020]
When the sliding bearing is made to slide between metal parts, in order to prevent damage during pump operation, it is necessary to increase the bearing area to suppress the bearing surface pressure, leading to an increase in the bearing area of the bearing. In the present invention, by using the resin portion as the sliding portion, it is possible to prevent such an increase in the bearing area and to suppress the sliding loss even when the sliding diameter of the bearing portion is increased.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0022]
A first embodiment of the present invention will be described with reference to FIGS.
[0023]
FIG. 2 is a longitudinal sectional view showing the entire structure of an embodiment in which a bearing portion is provided in the mouth ring portion on the drive side of the double suction centrifugal pump of the present invention, and FIG. 3 is a partially enlarged longitudinal section of portion A in FIG. FIG.
[0024]
In FIG. 2, both suction centrifugal pumps 1 are arranged in a substantially horizontal direction, and one end side (the right end side in FIG. 2) is not shown, but is driven as a driving means known as this kind via a coupling. A main shaft 2 connected to the machine, a double-suction centrifugal impeller 3 fixed to the center of the main shaft 2, a spiral casing 4 provided so as to contain the impeller 3, and the spiral casing 4 There are mouth ring portions 5a and 5b on the driving machine side (right side in FIG. 2) and driven machine side (left side in FIG. 2) close to the suction side portion 3a (described later) of the impeller 3.
[0025]
The spiral casing 4 has, for example, a double volute shape with a half crack structure in the figure, and is composed of an upper casing 4a, a lower casing 4b having a suction port 6 and a discharge port (not shown), and a bolt The upper casing 4a and the lower casing 4b are fastened and fixed to each other by the like (not shown). A shaft seal device 8 having a mechanical seal structure is provided in the main shaft 2 through portion 7a on the driving machine side in the spiral casing 4, for example, and a casing is provided in the main shaft 2 through portion 7b on the driven machine side. A cover 9 is provided.
[0026]
The impeller 3 allows water to flow from the pump suction passage 10 into the suction side portion 3a disposed on each of the driving machine side and the driven machine side, and is arranged on the radially outer peripheral side (upper side or lower side in FIG. 2). Water is allowed to flow into the pump discharge passage 11 from the provided discharge side portion 3b.
[0027]
The main shaft 2 is disposed in the driving machine side mouth ring portion 5a, and is disposed in the bearing portion 12 that receives the radial load, and the main shaft 2 penetrating portion 7b on the driven side of the spiral casing 4, and the radial load. It is supported rotatably via a bearing part 13 that receives the bearing and a bearing part 14 that receives a thrust load.
[0028]
The bearing portion 12 is a sliding bearing, which is fixed to the outer peripheral side of the suction side portion 3a of the impeller 3 and is a sliding portion 12A made of a metal material, and the inner peripheral side of the spiral casing 4 is the outer peripheral side of the sliding portion 12A. The sliding part 12B is provided so as to face and slide. The sliding portion 12B of the bearing portion 12 is made of a resin material, preferably PA (polyamide), POM (polyacetal), PBT (polybutylene terephthalate), PET (polyethylene terephthalate), PPE (polyphenylone ether), PC (polycarbonate). , UHMW-PE (ultra high molecular weight polyethylene), PTFE (polytetrafluoroethylene), PPS (polyphenylene sulfide), PI (polyimide), PEEK (poly ether ether ketone), PAR (polyarylate), PSF ( Polysulfone), PEI (polyetherimide), PAI (polyamideimide), PES (polyethersulfone), and at least one resin obtained by polymerizing cycloolefins capable of metathesis polymerization in the presence of a metathesis polymerization catalyst It is the material things, including. More preferably, PEEK (polyetheretherketone) reinforced with carbon fiber, PPS (polyphenylene sulfide) reinforced with carbon fiber, and cycloolefins capable of metathesis polymerization reinforced with carbon fiber in the presence of a metathesis polymerization catalyst. A material containing at least one kind of resin obtained by polymerizing is used as a material.
[0029]
The gap between the sliding portions 12A and 12B of the bearing portion 12 is the minimum clearance that can be established as a bearing, thereby minimizing the amount of leakage from the pump discharge passage 11 of the high pressure portion to the pump suction passage 10 of the low pressure portion. It is supposed to be suppressed.
[0030]
The bearing portion 13 is, for example, a slide bearing known as this type. The bearing portion 14 includes a disk 14a inserted at the driven side end of the main shaft 2, and an annular resin thrust pad 14b attached to the driven side of the disk 14a. A thrust direction load acting on both sides of the driven machine is received. Further, in the embodiment shown in FIG. 2, the bearing portion 14 has been described as having a structure that receives a load in the thrust direction acting on both the driving machine side and the driven machine side. However, the bearing portion 12 is provided on the driving machine side mouth ring portion 5a. In the case of the arrangement, the thrust load acts on the driven machine side from the relationship between the leakage amounts of the mouth ring portions 5a and 5b (5a side <5b side). For this reason, the said bearing part 14 is good also as a structure which receives only the thrust load which acts on the driven machine side depending on conditions.
[0031]
In addition, the driven liquid side of the swirl casing 4, and further the casing cover 9, the own liquid handled by the pump itself from the discharge side, preferably tap water or industrial water from the outside (the pump may be dry activated at the start of the pump, Further, in the case of a pump that is always used for suction, a negative pressure environment is provided), and water supply ports 15 for forcibly supplying the bearing portions 13 and 14 are provided.
[0032]
In the above description, the driving machine side and the driven machine side correspond to the connection side and the anti-connection side to the driving means described in the claims. The main shaft 2 constitutes a rotating shaft described in each claim.
[0033]
Next, the operation and effect of this embodiment will be described below.
[0034]
In the above-described suction pump 1 of the present invention, when used for pumping, for example, in water supply, agriculture, irrigation, etc., the drive shaft is driven to rotate the main shaft 2. Thereby, the impeller 3 rotates, sucks water from the water suction port 6 of the spiral casing 4, flows into the suction side portion 3 a of the impeller through the pump suction passage 10, and pressurizes the pressurized water. It flows out from the discharge side portion 3 b of the vehicle 3 and is discharged from the discharge port of the spiral casing 4 through the pump discharge side flow path 11.
[0035]
At this time, in the above-described embodiment of the present invention, the bearing portion 12 that receives the radial load is provided in the drive side mouth ring portion 5a adjacent to the suction side portion 3a of the impeller 3 inside the spiral casing 4. By supporting the impeller 3, the support side support position of the main shaft 2 is spiral compared to the conventional structure in which both ends of the main shaft are supported by bearing portions at the main shaft penetrating portions on the driver side and driven unit side of the spiral casing. The bearing span can be shortened by the amount corresponding to the mouth ring portion 5a (inside the spiral casing 4) from the main shaft 2 penetrating portion 7a (the position of the spiral casing 4 wall surface) of the casing 4. As a result, since the bending stress acting on the main shaft 2 is reduced, the diameter of the main shaft 2 is reduced, and the suction performance of the impeller 3 is improved, thereby reducing the occurrence of cavitation and increasing the speed. As a result, the pump performance can be improved and the pump can be downsized, so that the installation space can be reduced.
[0036]
In particular, the sliding portions 12A and 12B of the bearing portion 12, which are sliding bearings, increase the bearing area in order to prevent damage due to seizure during operation of the pump when a metal material is used for both of them. Therefore, it is necessary to suppress the bearing surface pressure, and the bearing area of the bearing portion 12 is increased. Moreover, the bearing part 12 is arrange | positioned at the drive side mouth ring part 5a, and compared with the conventional structure, the sliding diameter as a bearing becomes large and we are anxious about the increase in a sliding loss. In the present embodiment, the sliding portion 12A of the bearing portion 12 is made of a metal material, and the sliding portion 12B is made of a resin material having excellent sliding characteristics, thereby preventing an increase in the bearing area of the bearing portion 12. There is also an effect of suppressing the sliding loss to the level of the conventional structure.
[0037]
Further, as described above, since the bearing portion 12 is disposed in the driver side mouth ring portion 5a inside the spiral casing 4, self-lubrication is possible with the own liquid handled by the pump itself, so that the conventional structure is used. In addition, grease and oil for the purpose of lubrication can be eliminated, and forced water supply to the bearing portion 12 is also unnecessary.
[0038]
A second embodiment of the present invention will be described with reference to FIGS. The present embodiment is an embodiment in which the bearing portion is provided in the driven machine side mouth ring portion 5b.
[0039]
FIG. 4 is a longitudinal sectional view showing the entire structure of the double suction centrifugal pump according to the present embodiment, and FIG. 5 is a partially enlarged longitudinal sectional view of a portion B in FIG. 4 and 5, the same reference numerals are given to the same parts as those in the above embodiment, and the description will be omitted as appropriate.
[0040]
In the present embodiment, the main shaft 2 is disposed on the driven-side mouth ring portion 5b, receives a radial load and a thrust load in the driven-side direction, and a main shaft on the drive side of the spiral casing 4. It is arrange | positioned in 2 penetration part 7a, and is supported rotatably via the bearing part 17 which receives the radial direction load and the thrust direction load to a drive machine side direction. The end surface of the main shaft 2 on the driven machine side is accommodated inside the pump without penetrating the spiral casing 4, and an impeller nut 18 is provided to fix the impeller 3.
[0041]
The bearing portion 16 is a sliding bearing similar to the bearing portion 12, and includes a sliding portion 16 </ b> A extending from the outer peripheral side of the suction side portion 3 a of the impeller 3 to the vertical end surface side, and the inner periphery of the spiral casing 4. The sliding portion 16B is provided from the side to the inner vertical end face side, and each is provided with a sliding portion 16B provided so as to face and slide on the outer peripheral side and the vertical end face side of the sliding portion 16A. The sliding portion 16A of the bearing portion 16 is made of a metal material like the sliding portion 12A described above, and the sliding portion 16B is made of a resin material excellent in sliding characteristics like the aforementioned 12B.
[0042]
In the embodiment shown in FIGS. 4 and 5, when the bearing 16 is disposed in the driven-side mouth ring portion 5b, the thrust is determined from the relationship between the leakage amounts of the mouth ring portions 5a and 5b (5a side> 5b side). The load acts on the drive side. For this reason, the said bearing part 12 which receives only a radial load may be arrange | positioned to the driven machine side mouth ring part 5b depending on conditions.
[0043]
The bearing portion 17 is adapted to receive both a thrust direction load and a radial direction load in the direction of the driving machine side via a disk 19 provided at a position on the driven side surface of the bearing portion 17 in the main shaft 2.
[0044]
According to the present embodiment configured as described above, effects such as improvement in pump performance and reduction in installation space due to shortening of the bearing span can be obtained as in the above-described embodiment of the present invention. In addition to this, the driven machine side end portion of the main shaft 2 does not penetrate the spiral casing 4, so that the axial dimension can be further shortened. In addition, since the main shaft 2 does not penetrate the driven casing side of the spiral casing 4, the structure of the driven casing side of the spiral casing 4 can be greatly simplified. Moreover, since the bearing part 16 is arrange | positioned in the driven machine side mouth ring part 5b inside the spiral casing 4, since self-circulation is possible with the self-liquid which a bearing part pump itself handles, forced water supply becomes unnecessary.
[0045]
The bearing portion 17 is configured to receive both the radial direction load and the thrust direction load on the drive side, so that each bearing portion 13 that receives the radial direction load and the thrust direction load on the drive side, Compared with the first embodiment in which 14 is separately provided, the pump structure can be further simplified.
[0046]
A third embodiment of the present invention will be described with reference to FIG. The present embodiment is an embodiment in which bearing portions are provided on both the driving machine side and the driven machine side mouth ring portions 5a and 5b.
[0047]
FIG. 6 is a longitudinal sectional view showing the entire structure of the double suction centrifugal pump according to the present embodiment. In FIG. 6, parts that are the same as in the above embodiment are given the same reference numerals, and descriptions thereof are omitted as appropriate.
[0048]
In the present embodiment, the bearing portions 12 that receive the same radial load as those in the first embodiment are disposed on both the driving machine side and the driven machine side mouth ring portions 5a and 5b. And the bearing part 14 which receives the thrust direction load which acts on both directions of a drive machine side and a driven machine side is arrange | positioned in the main shaft 2 penetration part 7b by the side of the driven machine of the spiral casing 4, These spindle parts 12 and 14 carry out a spindle. 2 is rotatably supported.
[0049]
According to the present embodiment configured as described above, the support position on the driven machine side of the main shaft 2 is changed from the main shaft 2 penetrating portion 7b (the position of the wall surface of the spiral casing 4) to the mouth ring as compared with the first embodiment. The bearing span can be shortened more reliably by the amount corresponding to the portion 5b (inside the spiral casing 4). Therefore, the diameter of the main shaft 2 can be further reduced compared to the case of the first embodiment, the pump performance can be further improved, and the installation space can be reduced. Further, as in the first embodiment, the bearing portion 12 is always in a positive pressure environment except for the moment when the pump is started, and a stable water film is ensured, so that forced water supply is unnecessary.
[0050]
A fourth embodiment of the present invention will be described with reference to FIG. The present embodiment is an embodiment in which bearing parts for receiving a radial load and a thrust load in the driving machine side direction or the driven machine side direction are provided on the driving machine side and the driven machine side mouth ring parts 5a and 5b, respectively. .
[0051]
FIG. 7 is a longitudinal sectional view showing the entire structure of the double suction centrifugal pump according to the present embodiment. In FIG. 7, parts that are the same as in the above embodiment are given the same reference numerals, and descriptions thereof are omitted as appropriate.
[0052]
In the present embodiment, the main shaft 2 is disposed on the driven machine side mouth ring part 5b, and is arranged on the bearing part 16 that receives the radial load and the thrust direction load in the driven machine side direction, and the drive machine side mouth ring part 5a. It is provided and supported rotatably via a bearing portion 16 that receives a radial load and a thrust load in the direction toward the drive side. In other words, the main shaft 2 is supported only by the bearings 16 in the driving machine side and driven machine side mouth ring parts 5a and 5b. In addition, the driven machine side end surface of the main shaft 2 is housed in the pump without penetrating the spiral casing 4 as in the second embodiment, and an impeller nut 18 is provided to fix the impeller 3.
[0053]
According to the present embodiment configured as described above, as in the third embodiment, effects such as improvement of pump performance and reduction of installation space due to shortening of the bearing span can be obtained. Further, as in the second embodiment, the axial dimension of the main shaft 2 can be shortened, and the driven-side structure of the spiral casing 4 can be greatly simplified. Further, as in the second embodiment, the bearing portion 16 is always positive pressure except for the moment when the pump is started, and a stable water film is ensured, so that forced water supply is unnecessary.
[0054]
A fifth embodiment of the present invention will be described with reference to FIG. This embodiment is an embodiment in which the radial dimension (= eyeball diameter) of the mouth ring portion is made different between the driving machine side and the driven machine side.
[0055]
FIG. 8 is a longitudinal sectional view showing the entire structure of the double suction centrifugal pump according to the present embodiment. In FIG. 8, parts that are the same as in the above embodiment are given the same reference numerals, and descriptions thereof are omitted as appropriate.
[0056]
In the present embodiment, the bearing portions 12 and 16 are provided on both the driving machine side and the driven machine side mouth ring portions 5a and 5b. At this time, as in the second and fourth embodiments, the main shaft 2 is Since the spiral casing 4 does not penetrate the driven machine side, the eyeball diameter d1 of the driven machine impeller 3 (in other words, the radial dimension of the driven machine side mouth ring portion 5b) reaches an optimum diameter for improving the pump performance. It is small. In this way, when the eyeball diameter d1 of the impeller 3 on the driven machine side is made smaller than the eyeball diameter d2 of the impeller 3 on the drive machine side (in other words, the radial dimension of the drive side mouse ring part 5a), As disclosed in H8-28486, the thrust direction load can be applied only in one direction in the direction of the drive side based on the difference in the pressure receiving area of the working fluid (water). Thus, the main shaft 2 is disposed in the driving machine side mouth ring part 5a, and is disposed in the bearing part 16 that receives the radial direction load and the thrust direction load in the driving machine side direction, and the driven machine side mouth ring part 5b. The bearing portion 12 that receives a radial load is rotatably supported. The main shaft 2 is housed inside the pump without penetrating the driven machine side of the spiral casing 4 as in the second and fourth embodiments, and an impeller nut 18 is provided to fix the impeller 3.
[0057]
According to the present embodiment configured as described above, as in the fourth embodiment, effects such as improvement in pump performance and reduction in installation space by shortening the axial dimensions of the bearing span and the main shaft 2 are obtained. Further, as in the first to fourth embodiments, the bearing portions 12 and 16 are always in a positive pressure environment except for the moment when the pump is started, and a stable water film is secured, so that no forced water supply is required. .
[0058]
In addition, since the main shaft 2 does not penetrate the spiral casing 4 as in the second and fourth embodiments, the axial dimension can be shortened and the structure on the driven machine side of the spiral casing is greatly increased. Can be simplified. Furthermore, the eyeball diameter d1 of the impeller 3 on the driven machine side can be reduced to an optimum diameter for improving the pump performance. As a result, the relative speed of the water flowing into the suction side portion 3a of the impeller 3 is reduced, and the low pressure from the pump discharge flow path 11 of the high pressure portion via the driven side and the drive side mouth ring portions 5a and 5b. The amount of leakage into the pump suction flow path 10 can be reduced, and the pump performance can be further improved.
[0059]
【The invention's effect】
According to the present invention, since the bearing portion is provided in the mouth ring portion on at least one side close to the impeller suction side portion inside the spiral casing to support the impeller, the bearing span is greatly shortened and the pump performance is improved. It can be improved sufficiently and downsizing can be realized.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a conventional structure of a double suction centrifugal pump.
FIG. 2 is a longitudinal sectional view showing the overall structure of the first embodiment of the double suction centrifugal pump of the present invention.
FIG. 3 is a partially enlarged vertical sectional view of a portion A in FIG.
FIG. 4 is a longitudinal sectional view showing the overall structure of a second embodiment of the double suction centrifugal pump of the present invention.
5 is a partially enlarged longitudinal sectional view of a portion B in FIG.
FIG. 6 is a longitudinal sectional view showing the overall structure of a third embodiment of the double suction centrifugal pump of the present invention.
7 is a longitudinal sectional view showing the overall structure of a fourth embodiment of the double suction centrifugal pump of the present invention. FIG. 8 is a longitudinal sectional view showing the overall structure of the fifth embodiment of the dual suction centrifugal pump of the present invention. It is.
[Explanation of symbols]
1 Double suction centrifugal pump 2 Main shaft (rotary shaft)
DESCRIPTION OF SYMBOLS 3 Impeller 3a Impeller suction side part 3b Impeller discharge side part 4 Swirl casing 4a Upper casing 4b Lower casing 5a Mouse ring part 5b on the driving machine side Mouse ring part 6 on the driven machine side Suction port 7a Drive of the spiral casing Main shaft through portion 7b on the machine side Main shaft through portion 8 on the driven machine side of the spiral casing 9 Shaft seal device 9 Casing cover 10 Pump suction passage 11 Pump discharge passage 12 Bearing portion 12A Impeller side sliding portion 12B Spiral casing side sliding Part 13 Bearing part 14 Thrust bearing part 14a Disc 14b Thrust pad 15 Water supply port 16 Bearing part 16A Impeller side sliding part 16B Spiral casing side sliding part 17 Bearing part 18 Impeller nut 19 Disc

Claims (5)

  A rotating shaft arranged in a substantially horizontal direction, fixed to the rotating shaft, and allows fluid to flow in from the connecting side to the driving means and the anti-connecting side of the rotating shaft, and between the connecting side and the anti-connecting side. A double suction centrifugal pump having a double suction centrifugal impeller that causes the fluid to flow radially outward at a portion and a spiral casing provided so as to contain the impeller, the connection side and the anti-connection side A double suction centrifugal pump characterized in that both mouth ring portions are provided with bearing portions that rotatably support the impeller. 2. The double suction centrifugal pump according to claim 1 , wherein bearing portions provided on both of the mouth ring portions on the connection side and the anti-connection side receive only a radial load. 2. The double suction centrifugal pump according to claim 1 , wherein the bearing portions provided on both of the mouth ring portions on the connection side and the anti-connection side receive both a radial load and a thrust load. pump. The double suction centrifugal pump according to claim 3 , wherein a diameter of the anti-connection side of the mouth ring portions on the connection side and the anti-connection side is smaller than a diameter of the connection side. . The double suction centrifugal pump according to any one of claims 1 to 4 , wherein the bearing portion is a sliding bearing provided with a sliding portion made of a resin member.

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