JP2002257095A - Mixed or axial flow pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mixed or axial flow pump capable of shortening length form a impeller to a delivery center and setting an installation level of a delivery pipe at a low position by eliminating a delivery bowl including a guide van for reducing a civil and construction work cost for a machine installation place, and controlling expansion of a installation space in a horizontal direction by keeping projection in a radial direction small. SOLUTION: An inlet 26 of an elbow shaped delivery casing 25 is connected downstream of a suction casing 4 rotatably housing either of a mixed or axial flow impeller 3. An outlet 27 of the delivery casing 25 is opened toward a direction C2 crossing at right angles with an axial line of the inlet 26. An inclined guide surface 28 liquid-tightly enclosing a surface of a cylindrical bearing part 1B from a starting point P1 of the inlet 26 side over an end point P2 of the outlet 27 side and spirally rising toward a rotating direction of the impeller 3 is formed on the delivery casing 25.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mixed-flow or axial-flow pump, and more particularly to a mixed-flow or axial-flow pump in which the axial dimension of the spindle is largely reduced while avoiding an increase in the axial dimension of the spindle. Related to pumps.

[0002]

2. Description of the Related Art Conventionally, a vertical mixed flow pump shown in FIG. 4 has been known. This vertical shaft mixed flow pump has a plurality of bearings 1,
1, a main shaft 2 rotatably supported by a vertical shaft, a mixed flow impeller 3 fixed to the lower end of the main shaft 2, a discharge bowl 4 rotatably housing the impeller 3, and a discharge bowl 4. A vertical pumping pipe 5 penetrating the main shaft 2 and being connected above the pumping bowl 4, and a liquid-tight and rotatable penetrating main shaft 2 penetrating the pumping pipe 5; A discharge bell 6 is provided on the upper side, and a suction bell 7 is provided downwardly in communication with the inside of the discharge bowl 4, and a discharge valve 8 and a discharge pipe 9 are provided downstream of the discharge curved tube 6. I have. The outlet of the discharge pipe 9 faces the inside of the discharge water tank 10, and a flap valve 11 for preventing backflow is attached to this outlet.

The main shaft 2 extending above the discharge curved pipe 6 is connected to a reduction gear 14 via couplings 12 and 12 and a connecting shaft 13.
The horizontal input rotary shaft 16 of the speed reducer 14 is connected to a coupling 17, 17.
And a connection shaft 18 or the like, and is connected to a horizontal output rotation shaft 20 of a prime mover (such as a diesel engine) 19.

[0004] A building 21 of a drainage station provided with a vertical mixed-flow pump has a two-floor structure having a lower floor 22 on which a pump is installed and an upper floor 23 on which a reducer 14 and a motor 19 are installed. It has become.

On the other hand, as shown in FIG.
Vertical axial flow pumps of mm or more are known. This type of large-diameter vertical axial flow pump is constructed by forming a discharge bowl 4, a suction bell 7, and a water pump 5 from a steel plate, and burying a part of this in concrete. In the vertical axial flow pump of FIG. 5, the same or corresponding parts as those of the vertical mixed flow pump of FIG.

[0006]

However, in the conventional vertical mixed flow pump and vertical axial flow pump, the length L from the impeller 3 to the discharge center C1 of the discharge curved pipe 6 is long, and Since the installation level of the discharge pipe 6 connected to the outlet side is set at a high position, there is a problem that civil and construction work costs for constructing the drainage pump station increase.

On the other hand, there is a volute type vertical mixed-flow pump in which a spiral casing is provided on the outer periphery of the impeller 3 so as to convert the rotational speed energy emitted from the impeller 3 into pressure energy. In this type of pump, the axial length L of the main shaft 2 from the impeller 3 to the discharge center can be reduced. However, since the spiral casing has a large amount of protrusion of the main shaft 2 in the radial direction, a horizontal installation space becomes large.

[0008] Therefore, the present invention reduces the length from the impeller to the discharge center by omitting the use of a discharge bowl having guide blades, and sets the installation level of the discharge pipe at a low position. In order to build an airplane,
It is an object of the present invention to provide a diagonal flow or axial flow pump that can reduce building work costs, reduce the amount of radial extension of a main shaft, and suppress the expansion of a horizontal installation space. And

[0009]

According to one aspect of the present invention, a cylindrical bearing portion rotatably supporting a main shaft and a mixed flow impeller rotating simultaneously with the main shaft are provided. Alternatively, in a mixed flow or axial flow pump including an axial flow impeller and a suction casing rotatably accommodating one of these impellers, the cylindrical bearing portion and the main shaft are provided downstream of the suction casing. An inlet of an elbow-shaped discharge casing led to the outside is connected, an outlet of the discharge casing is opened in a direction intersecting the axis of the inlet, and the discharge casing has an outlet from a starting point on the inlet side. The inclined guide surface is formed so as to spiral up toward the rotation direction of the impeller toward the end point on the side.

[0010] The maximum inner diameter of the discharge casing in the axial section direction of the main shaft can be set to 1.3 times or less the outer diameter of the impeller.

According to the first aspect of the present invention, the inlet of the discharge casing is connected to the downstream of the suction casing that rotatably accommodates either the mixed flow impeller or the axial flow impeller, and the outlet of the discharge casing. Is open in a direction intersecting the axis of the inlet, so that the length from the impeller to the discharge center of the discharge casing can be significantly reduced,
The installation level of the discharge pipe connected to the outlet of the discharge casing can be set at a low position, the amount of radial extension of the discharge casing can be reduced, and the expansion of the horizontal installation space can be suppressed. .

Further, the liquid that has flowed out of the impeller is guided by an inclined guide surface that rises spirally in the direction of rotation of the impeller, and flows spirally from the inlet to the outlet of the elbow-shaped discharge casing. In this process, the turning velocity energy of the liquid discharged from the impeller can be effectively converted into pressure energy.

According to the second aspect of the present invention, by setting the maximum inner diameter of the discharge casing in the cross-sectional direction of the main shaft to 1.3 times or less the outer diameter of the impeller, the amount of the main shaft protruding in the radial direction can be reduced. By keeping it small, the installation space in the lateral direction can be reliably reduced.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional front view showing an embodiment of a mixed flow pump according to the present invention, and FIG. 2 is a plan view of FIG. Note that the same or corresponding parts as those of the conventional mixed flow vertical shaft pump described with reference to FIG.

1 and 2, a vertical main shaft 2 is rotatable by a cylindrical bearing portion 1B comprising a plurality of bearings 1, 1... And a bearing tube 1A accommodating the bearings 1, 1.. The diagonal flow impeller 3, which is supported at the lower end of the main shaft 2 so as to be able to rotate simultaneously, has a suction casing 4.
The suction bell 7 is provided rotatably and communicated with the inside of the suction casing 4 in a downward direction.

Downstream of the suction casing 4, an inlet 26 of an elbow-shaped discharge casing 25 is connected.
7 is open in the direction of the axis C2 of the inlet 26, that is, the axis C2 orthogonal to the axis C of the main shaft 2. The inlet 26 is formed in a circular shape corresponding to the outlet of the suction casing 4, and the outlet 27 is formed in a square or circular shape. Have been. Further, the maximum inner diameter D of the discharge casing 25 in the axial section direction of the main shaft 2 is set to be 1.3 times or less the outer diameter D1 of the impeller. Further, a cylindrical bearing portion 1B is inserted from the inside of the elbow-shaped discharge casing 25.
And the main shaft 2 are led upward.

On the other hand, the discharge casing 25 has an inlet 26
As a lead, a straight line connecting the starting point P1 closest to the outlet 27 and the end point P2 farthest from the starting point P1 at the outlet 27 surrounds the surface of the cylindrical bearing portion 1B in a liquid-tight manner, and spirals in the rotation direction of the impeller 3. An inclined guide surface 28 that rises up is formed.

With such a construction, the discharge center C2 of the elbow-shaped discharge casing 25 from the mixed flow impeller 3 is omitted because the discharge bowl having the guide blades is omitted.
The length L1 can be greatly reduced as compared with the conventional length L described with reference to FIG. Therefore, the installation level of the discharge pipe 9 connected to the outlet 27 of the discharge casing 25 via the different-diameter pipe 29 can be set at a low position (the level indicated by the two-dot chain line in FIG. 4). Civil and construction work costs can be reduced. Moreover, by connecting an elbow-shaped discharge casing 25 downstream of the suction casing 4 and setting the maximum inner diameter of the discharge casing 25 in the axial cross-sectional direction of the main shaft 2 to 1.3 times or less the outer diameter of the impeller, The amount of overhang in the radial direction
Expansion of the installation space in the lateral direction can be suppressed.

Further, the water discharged from the mixed flow impeller 3 surrounds the surface of the cylindrical bearing portion 1B in a liquid-tight manner, and is guided to the inclined guide surface 28 which rises spirally in the rotation direction of the impeller 3. The inlet 26 of the elbow-shaped discharge casing 25
Flows spirally toward the outlet 27, and in this process, the turning velocity energy of the water discharged from the impeller 3 can be effectively converted into pressure energy and discharged to the discharge pipe 9.

Next, an axial pump according to the present invention will be described. FIG. 3 is a longitudinal sectional view showing one embodiment of the axial flow pump according to the present invention. 1 and 2
The configuration different from the mixed flow pump described in the above is that an axial impeller is used as the impeller 3, and the suction casing 4 is made of a thin steel plate.
The suction bell 7 and the discharge casing 25 are made and buried in concrete, and the other structures are almost the same as those of the mixed flow pump described with reference to FIGS. 1 and 2. Are denoted by the same reference numerals as those of the mixed flow pump, and redundant description of the structure is omitted.

In the axial-flow pump having the above-described configuration, the length L1 from the axial-flow impeller 3 to the discharge center C2 of the elbow-shaped discharge casing 25 is reduced by omitting the discharge bowl having the guide blades. 5 can be significantly reduced as compared with the conventional length L described in FIG. For this reason, the installation level of the discharge pipe 9 connected via the outlet 27 of the discharge casing 25 via the different diameter pipe 29 can be set at a low position (the level of the two-dot chain in FIG. 5), and thus a drainage pump station is constructed. Civil and construction work costs can be reduced. Further, by connecting an elbow-shaped discharge casing 25 downstream of the suction casing 4 and setting the maximum inner diameter of the discharge casing 25 in the axial cross-sectional direction of the main shaft 2 to 1.3 times or less the outer diameter of the impeller, the main shaft 2 The amount of overhang in the radial direction
Expansion of the installation space in the lateral direction can be suppressed.

Further, the water discharged from the axial impeller 3 surrounds the surface of the cylindrical bearing portion 1B in a liquid-tight manner and is guided to the inclined guide surface 28 which rises spirally in the rotation direction of the impeller 3. The inlet 26 of the elbow-shaped discharge casing 25
Flows spirally toward the outlet 27, and in this process, the turning velocity energy of the water discharged from the impeller 3 can be effectively converted into pressure energy and discharged to the discharge pipe 9.

In the above embodiment, the vertical mixed flow pump and the vertical axial flow pump having the main shaft 2 in the vertical direction have been described. However, the present invention is not limited to the above embodiment, but is applied to a horizontal axial pump. It can be embodied as a horizontal-axis diagonal pump with a directional main shaft 2 or a horizontal-axis axial flow pump.

[0024]

As described above, since the mixed flow or axial flow pump according to the present invention is constituted, the following special effects can be obtained.

That is, according to the present invention, the length from the impeller to the discharge center of the discharge casing is greatly reduced, and the installation level of the discharge pipe connected to the outlet of the discharge casing is set at a low position. Can reduce the cost of civil engineering and construction work for building the airfield. Moreover, by connecting the elbow-shaped discharge casing downstream of the suction casing, the amount of protrusion of the discharge casing in the radial direction of the main shaft can be reduced, and the expansion of the installation space in the lateral direction can be suppressed.

According to a second aspect of the present invention, by setting the maximum inner diameter of the discharge casing in the cross-sectional direction of the main shaft to 1.3 times or less the outer diameter of the impeller, the amount of protrusion of the discharge casing in the main shaft radial direction is reduced. Can be kept small, and the horizontal installation space can be reliably reduced.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional front view showing an embodiment of a mixed flow pump according to the present invention.

FIG. 2 is a plan view of FIG.

FIG. 3 is a longitudinal sectional front view showing one embodiment of an axial flow pump according to the present invention.

FIG. 4 is a schematic configuration diagram showing a conventional vertical mixed flow pump.

FIG. 5 is a schematic configuration diagram showing a conventional vertical axial pump.

[Explanation of symbols]

 1B Cylindrical bearing part 2 Main shaft 3 Mixed-flow impeller or axial-flow impeller 4 Suction casing 25 Elbow-shaped discharge casing 26 Inlet of discharge casing 27 Exit of discharge casing 28 Slant guide surface C Inlet of discharge casing Axis C2 axis of outlet of discharge casing P1 starting point of inlet side of discharge casing P2 end point of outlet side of discharge casing

Claims (2)

[Claims] 1. A cylindrical bearing portion rotatably supporting a main shaft, a mixed flow impeller or an axial flow impeller which rotates simultaneously with the main shaft, and a suction casing accommodating any one of these impellers rotatably. In the mixed flow or axial flow pump comprising: an inlet of an elbow-shaped discharge casing having the cylindrical bearing portion and a main shaft led out is connected downstream of the suction casing, and an outlet of the discharge casing is connected to an outlet of the discharge casing. The inclined guide surface which opens in a direction intersecting with the axis of the inlet, and which rises spirally in the rotation direction of the impeller from the starting point on the inlet side to the end point on the outlet side, is provided on the discharge casing. A mixed-flow or axial-flow pump, wherein 2. The mixed flow or axial flow pump according to claim 1, wherein a maximum inner diameter of the discharge casing in a cross-sectional direction of the main shaft is set to 1.3 times or less of an outer diameter of the impeller.