JPS5944518B2 - Intermediate casing for vertical multistage pumps - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vertical multistage pump in which a plurality of circular pump casings are stacked and integrated on a suction and discharge casing having a suction port and a discharge port on the opposite side of the suction port.

In horizontal multi-stage pumps, the load on the pump shaft acts perpendicularly to the axis, causing the shaft to flex, resulting in larger bearings and other parts, which not only increases the installation area in proportion to the number of stages, but also There is a drawback that a larger installation area is required due to the increased size of the pump, so vertical pumps have been considered in order to eliminate this problem.

However, if the horizontal type were simply changed to the vertical type, the suction port would be located at the bottom of the pump, and the discharge port would be located at the top of the pump, and a suction pipe and a discharge pipe would be installed at these suction ports and discharge ports, respectively. Directly connecting the pipes would cause problems such as the pipes being at different levels.

That is, it is preferable that the suction pipe and the discharge pipe are installed at the same height.

Therefore, in order to meet this requirement, it is conceivable to set the suction pipe and the discharge pipe at the same height, and to connect the upper pump discharge port and the lower discharge pipe with another auxiliary pipe.

However, with this design, the auxiliary pipe is exposed to the outside of the pump, which is not only unsightly, but also has drawbacks such as requiring a large number of manufacturing parts and restricting the location where the pump can be installed.

The present invention has been made in view of the above points, and provides a vertical multi-stage pump that can be assembled by simply stacking them, and that allows suction pipes and discharge pipes to be arranged in the same direction without using auxiliary pipes. The purpose is to

According to the invention, each pump casing has an impeller chamber in which the impeller is arranged, and radially outwardly of the impeller chamber,
First and second peripheral walls are formed, and the first and second peripheral walls are connected to the casing wall of the pump casing, and a first partition wall and a second partition wall are provided in the axial direction of the impeller chamber. Two volute chambers, through which the fluid from the impeller chamber passes, are formed diametrically opposite to each other between the peripheral wall and the casing wall, and two return passages are separated from the volute chambers. are formed to face each other in the diametrical direction, and a communication passage communicating with the volute chamber is formed between the first partition wall and the second partition wall, and the volute chamber of the final stage pump casing communicates with the return passage. ing.

Therefore, the fluid flowing into the suction and discharge casing from the suction port enters the radially outward volute chamber due to the rotation of the impeller, and passes through the communication passage between the first partition wall and the second partition wall to the next stage. is sucked into the impeller.

The fluid discharged from the final stage impeller flows through the return passage to the discharge port of the suction and discharge casing.

Therefore, a pump can be made by stacking a plurality of pump casings in a place where the suction pipe and the discharge pipe are arranged at the same height.

Also, since the return passage is provided inside the pump casing, it is compact and has a good appearance.

Furthermore, since the volute chamber and the return passage are provided diametrically opposite each other, the forces of the fluid flow acting on the pump casing are balanced, and the pump casing is not unduly distorted, resulting in less noise.

In carrying out the present invention, since the pump casing is stacked in multiple stages, the communication passage formed by the first partition wall and the second partition wall may be provided on the suction side of the impeller or on the discharge side. It may be provided.

That is, the communication passage may communicate the volute chamber of the pump at the front stage with the suction port of the impeller of the pump at the rear stage.

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

A vertical multi-stage pump embodying the present invention is shown in FIG. 4, with a casing 1 shown in FIGS.
It is formed by stacking them in multiple stages.

This casing 1 is made by casting.

The casing 1 has a pair of peripheral walls 2a extending in the circumferential direction.
, 2b and a first partition wall 3 that extends horizontally and partitions the vertical direction in FIG. The impeller 5 of the pump, shown in FIG. 3), is placed during assembly of the pump.

On the outside of the impeller chamber 4, there is a volute chamber 6 communicating therewith.
are provided facing each other in the diametrical direction, and these two volute chambers 6 are formed by expanding the first and second peripheral walls 2a, 2b in a spiral shape.

In the volute chamber 6, a guide wall 7 is formed by an extension of the first and second peripheral walls 2ab. Connected to wall C.

The casing 1 also has a communication passage 8 that communicates with the volute chamber 6 and guides discharged fluid from the volute chamber 6 to the next impeller. It is formed by the second partition wall 9 at the upper part of.

Furthermore, the casing 1 has a return passage 10 through which fluid from the final stage impeller passes, as described later, and this return passage 10 is formed between the inner peripheral walls 2a, 2b and the casing wall C. .

Note that 12 is a stepped portion into which the next casing fits when the pump casings 1 are stacked, and 13 is a bolt hole through which a bolt for fastening each casing is inserted.

The pump casing 1 having the above configuration has a fourth
As shown in the figure, the suction and discharge casings 15 that have been manufactured separately in advance are stacked one after another, and at the same time, the impeller 5 is assembled onto the pump shaft 16, and the final stage casing 17 is placed on the final stage. Required portions of each casing are sealed by sealing means (not shown) and fastened with bolts, and a motor is connected to the pump shaft 16.

This suction and discharge casing 15 has a suction port 18 on one side and a discharge port 19 on the opposite side, and the suction port 18 communicates with the suction portion of an impeller installed directly above the suction port 18.
The discharge port 19 communicates with the return passage 10.

In addition, in FIG. 4, the pump casing 1 is the same as iv in FIG. 3.
Although the drawing is shown as a right-angled cross section indicated by line -iv, the suction and discharge casing 15 is shown as a normal straight cross section.

In FIG. 4, the return passage 10 directly communicates with the discharge port 19 from above to make the explanation easier to understand, but in reality, the suction and discharge casing communicates with the discharge port 19 through a semicircular passage (not shown). It is connected to 19.

In operation, when a motor (not shown) is started, the pump operates in a known manner, and fluid flows from the suction port 18 to the impeller 5.
The tag is sucked in and sent from there to the volute chamber 6 by the centrifugal force of the impeller 5.

The fluid sent to the polyte chamber 6 passes through the communication passage 8,
The tag is sent to the impeller of the next stage. While repeating this operation 71 times in each stage, the pressure is increased and sent to the final stage casing 17.

The fluid whose pressure is further increased in the final stage passes through the return passage 10 and is discharged from the discharge port 19 of the suction and discharge casing 15.

Note that two volute chambers 6 and two return passages 10 are provided diametrically opposite to the casing in consideration of fluid balance.

5 to 7 show an example of a pump casing formed by processing a steel plate into a sheet metal.

This pump casing is designated by the reference numeral 21, and includes an impeller chamber 24 in which an impeller 25 is arranged, a volute chamber 26, a communication passage 28 communicating with an adjacent impeller, and a return passage 30. and a bolt hole 33, and each of these parts has the same function as the corresponding part in the first embodiment.

This pump casing 21 made by sheet metal molding is
For example, a pump unit can be made by integrally joining five members as shown in FIG.

In FIG. 8, the first member 37 is formed by bending a plate into a U-shape to form the volute chamber 26, and its radially inner portion is the first member 37 when viewed as a pump unit. and constitutes a part of the second peripheral wall.

The second member 38 is a horizontal plate portion 4 extending in the horizontal direction.
0 and a vertical portion 39 that is bent upward at a right angle from the radial outer circumference of the plate portion 40. As can be seen from FIGS. 6 and 9, when viewed as a pump unit, the vertical portion 39 is The horizontal portion 40 forms the other portions of the first and second peripheral walls, and the horizontal portion 40 forms the first partition wall.

The third member 41 is connected to the second member 38 and also to the horizontal portion 4.
3 and a cylindrical vertical part 42, a horizontal part 43 overlaps with the horizontal part 40 and constitutes a first partition wall, and as a pump unit, the cylindrical vertical part 42 constitutes a casing wall. There is.

The fourth member 44 is a horizontal portion 43 that constitutes the communication passage 28.
The fifth member 45 constitutes a second partition wall.

The casing 21 shown in FIGS. 5 to 7 is manufactured by overlapping the first to fifth members described above and welding the joints of each member into one piece.

At that time, the horizontal portion 40.43 that constitutes the first partition wall is
It is preferable to weld the annular projections 46 formed on these by projection welding, and the horizontal portions 40.
It is also possible to omit either one of 43.

As shown in FIG. 9, the pump casing 21 is assembled by sequentially stacking a suction and discharge casing 47 that has been prepared separately, placing a cover 48 on top, and fastening these together with bolts.

A pump drive motor (not shown) is mounted above the cover 48.

The pump assembled as described above operates in the same manner as in the previous embodiment.

As described above, the vertical multistage pump according to the present invention has the above-described configuration, and can be used in a place where a plurality of pump casings can be stacked and assembled to form a pump, and where the suction pipe and the discharge pipe are installed at the same height. can do.

Therefore, there is no need to use elbows or the like for piping.

Further, since the return passage is formed inside the pump casing, the pump is more compact and has a better appearance than a system in which the return pipe for discharged fluid is disposed outside the pump.

Furthermore, since each stage of the pump casing is made independently and integrally, it can be assembled by simply stacking them, reducing the number of parts needed for assembly and reducing labor and costs for assembly. .

In particular, according to the present invention, since it is of the volute type, it is more efficient and has less noise over a wider water flow range than the guide vane type.

Furthermore, when stacking the pumps, if the holes for the tightening bolts are appropriately provided outside the impeller chamber of the pump casing, a compact, circular structure with a good appearance can be obtained.

In addition, as a so-called double volute type, two volute chambers are provided at opposite positions of the pump casing.
In addition, since there are two return passages at opposite positions, the force of the fluid flow acting on the pump casing 1 is balanced, so the casing does not become unreasonably distorted and noise is reduced, making it suitable for use as a vertical multi-stage pump. The rotating shaft is not curved, which is extremely suitable.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of the casing taken along line I-I in Fig. 2, showing an embodiment of the pump casing of a vertical multi-stage pump according to the present invention, and Fig. 2 is taken along line H-■ in Fig. 1. 3 is a vertical sectional view of the casing; FIG. 3 is a horizontal sectional view taken along the line ■-■ in FIG. 4 showing the case where the casing is assembled; FIG. 5 is a horizontal sectional view taken along the line V-■ in FIG. 6 showing another embodiment of the present invention; FIG.
FIG. 7 is a view taken along line VI, FIG. 7 is a view taken along line ■-■ in FIG. 6, and FIG. 8 is prepared for manufacturing the casing shown in FIGS. 5 to 7. Diagram showing each member, No. 9
This figure shows the assembled state of the casing shown in FIGS. 5 to 7, and is a longitudinal cross-sectional view of only the pump casing in the section shown in FIG. 6. 1.21...Pump casing, 4,24...
... Impeller room, 6, 26... Volute chamber, 8, 28... Communication passage.

Claims (1)

[Claims] 1. In a vertical multi-stage pump in which a plurality of circular pump casings are stacked and integrated on a suction and discharge casing having a suction port and a discharge port on the opposite side of the suction port, each pump casing is provided with an impeller. Has an impeller chamber,
First and second circumferential walls are formed radially outwardly of the impeller chamber, the first and second circumferential walls are connected to the casing wall of the pump casing, and the first and second circumferential walls are connected to the casing wall of the pump casing, and , a first partition wall and a second partition wall are provided, and two volute chambers through which fluid from the impeller chamber passes are formed diametrically opposite between the first and second peripheral walls and the casing wall. Two return passages separated from the volute chambers are formed diametrically opposite to each other, and a communication passage communicating with the volute chamber is formed between the first partition wall and the second partition wall. A vertical multistage pump characterized in that a volute chamber of a final stage pump casing communicates with the return passage.