JPH11173296A - Diffuser device for pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate maintenance of a flow passage even when a diffuser vane is long and bent. SOLUTION: In this diffuser device for a pump which has a flow inlet on the upstream side, an impeller 15 inside, and an outlet pipe 26 connected with its back stream side, a diffuser casing provided on the radially outside of a flow passage P consists of a first diffuser easing 8 and a second diffuser casing 24 which are divided in the axial direction and are inter-engaged on a joining surface 23, and their casings are fixed each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diffuser device for a pump, particularly a low specific speed pump.

[0002]

2. Description of the Related Art FIG. 5 shows a diffuser device which is generally used. When assembled as a pump, an impeller is installed in an opening O thereof, and a radially outer portion is surrounded by a diffuser casing (not shown). Have been.
The example of FIG. 5 has seven diffuser vanes V and an intermediate vane M on the downstream side. Therefore, the liquid from the impeller passes through the flow path P between the two diffuser vanes V and moves to the downstream side while the speed head is converted into a pressure head.

[0003] Such a diffuser device D and a diffuser casing surrounding the outside in the radial direction are all integrally cast. In pumps having a relatively low specific speed of 400 or less, a closed impeller is used. As can be seen from FIG. 4, the inlet angle is small, and the turning angle is increased in order to recover the pressure. It is necessary to increase the length. When the liquid path P is long in a meandering manner, it is not sufficient to use a special tool to care for the flow path P from the axial direction of the pump, and the integral diffuser casing must be removed. Requires work close to overhaul.

[0004]

SUMMARY OF THE INVENTION Accordingly, it is a primary object of the present invention to provide a pump diffuser device in which the care of the flow path is simple.

Another object of the present invention is to provide a pump diffuser device which is easy to disassemble and assemble and can be easily cleaned and cleaned.

Another object of the present invention is to provide a diffuser vane design and a pump diffuser device having a large degree of freedom.

[0007]

SUMMARY OF THE INVENTION According to the present invention, there is provided a diffuser device for a pump having an inlet on an upstream side, an impeller provided therein, and a downstream side connected to an outlet pipe. A first diffuser casing and a second diffuser casing which are divided in the axial direction and are engaged with each other at a joint surface are provided in a diffuser casing provided radially outward of the road, and the casings are fixed to each other by fixing means. .

According to the present invention, a first diffuser vane is provided radially inward of the first diffuser casing, and a first central portion is provided radially inward of the first diffuser vane. A second diffuser vane separate from the first diffuser vane is provided radially inward of the second diffuser casing, and a second central portion is provided radially inward of the second diffuser vane. I have.

Therefore, the divided first and second diffuser casings are integrally fixed by any fixing means such as a tie rod or a flange. When the first diffuser casing is removed, the outside of the first diffuser vane in the radial direction is opened, so that maintenance can be easily performed.

[0010] The joint surface of the first and second diffuser casings is preferably a portion where the flow path expands in the radial direction, but the second diffuser casing can be pulled out in the axial direction even slightly upstream. This position is arbitrary depending on the manner of dividing and fixing the diffuser casing, the diffuser vane, and the central portion.

[0011]

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

FIG. 1 shows a first embodiment of the present invention. In the figure, a flange 2 of an inlet pipe 1 is detachably attached to an inlet side flange 4 of a bell mouth 3 and a bolt 5 by a nut 6. The outlet side flange 7 of the bell mouth 3 is connected to the flange 9 of the first diffuser casing 8.
Are removably fixed by bolts 11 and nuts 10 in the radial direction. A closed impeller 15 is accommodated inside the first diffuser casing 8 in the radial direction.

A diffuser vane 16 is separately provided radially inward of the first diffuser casing 8, and the diffuser vane 16 has a portion 16a extending to the downstream side (to the right in FIG. 1). I have. A central portion 17 is provided integrally inside the diffuser vane 16 in the radial direction. In the illustrated embodiment, the inlet pipe 1 and the bell mouth 3 are provided, but these are not necessarily provided when the present invention is implemented.

In the example shown in FIG. 1, since the first diffuser casing 8 and the diffuser vane 16 are separate bodies, if the first diffuser vane 16 is removed, the impeller 15 can be removed. . However, if the first diffuser casing 8 and the diffuser vane 16 are integrated as described later, the opening 14 must be dimensioned so that the impeller 15 can be inserted as shown in FIG.

A rotating shaft 20 of the impeller 15 is provided in the center portion 17, and the rotating shaft 20 is rotatably supported by a bearing 21. In the figure, reference numeral 22 denotes a liner ring.

The first diffuser casing 8 is liquid-tightly joined to the second diffuser casing 24 via a joint surface 23. Therefore, a flow path P is formed between the first diffuser casing 8 and the second diffuser casing 24 and the central portion 17. If this joint surface 23 is provided on the portion where the flow path P extends radially outward or on the left side, that is, on the inlet side in the drawing, the first diffuser casing 8 can be removed as described later.

The flange 42 of the outlet pipe 26 is fixed to the flange 25 on the downstream side of the second diffuser casing 24 with bolts 41. In order to integrate the first diffuser casing 8 and the separate second diffuser casing, the flange 9 of the first diffuser casing 8 and the flange 25 of the second diffuser casing 24 are a plurality of fixing means. Tie rods 29. That is, both ends of the tie rod 29 are fixed to the flanges 9 and 25 by the nuts 27 and 27 and have an adjusting portion 28 which can be extended and contracted in the middle.

Accordingly, if the nut 27 is removed to release the tie rod 29 and the bolt 11 is removed, the first diffuser casing 8 can be removed to the left in the drawing.

Then, the upstream side (left side in the drawing) of the joining surface 23 is exposed as shown in FIG. 5, so that the passage and the diffuser vane 16 can be easily cleaned.

FIG. 2 shows a second embodiment of the present invention. In the example of FIG. 1, only the diffuser casing is divided, but in the example of FIG. 2, the diffuser casing, the diffuser vane, and the central portion are all divided. Therefore, the same components as those in FIG. 1 are denoted by the same reference numerals, and only different configurations will be described.

The bell mouth 3a has a flange 30 at the place where the suction passage is narrowest in the example shown. That is, in the illustrated example, the disassembled surface is formed at a portion where the flow path P is bulged radially outward. However,
Any position on the division plane may be provided on the upstream side. Then, a first diffuser casing 31 is attached to the flange 30 by bolts 38. A first diffuser vane 32 is separately provided radially inward of the first diffuser casing 31 on the downstream side of the first diffuser casing 31, and a first central portion 33 is provided radially inward of the first diffuser vane 32. . In the illustrated example, the first diffuser vane 32 and the first central portion 33 are integrated. However, when the diameter of the opening 14 of the first diffuser casing is increased as in the configuration of FIG. 1, the first diffuser casing 31 and the first diffuser vane 32
And the first central portion 33 may be integrally formed. A second diffuser vane 35 is provided separately on the radially inner side of the second diffuser casing 34 engaged with the first diffuser casing 31 at the joint surface 23, and the radius of the second diffuser vane 35 is provided separately. A second central portion 36 engaged with the first central portion 33 at the joint surface 37 is provided integrally inward in the direction.

One end of a tie rod 29 is fixed to a flange 40 extending radially outward from the bell mouth 3a by a nut 27 so as to be adjustable.

Therefore, at the time of disassembly, the tie rod 29 is detached in this embodiment, the bolt 38 is detached, and the first diffuser casing 31 is detached. Then, the impeller 15 is removed, and the integrally formed first diffuser vane 32 and the first central portion 33 may be moved in the axial direction. Therefore, care of the flow path P can be facilitated.

The embodiment shown in FIG. 3 corresponds to the tie rod 2 shown in FIG.
9 instead of the first diffuser casing 31 and the second diffuser casing 31.
This is an example in which flanges 41 and 42 are fixed with bolts 43 and nuts 44 as fixing means to the diffuser casing 34.

That is, the flange 41 is provided at the downstream end of the first diffuser casing 31, and the flange 42 is provided at the upstream end of the second diffuser casing 34.
And the flanges 41 and 42 are bolted 43 and nut 4
4 is used for fixing. The other points are substantially the same as those in FIG. The operation and effect of this embodiment are the same as those of the above embodiment.

FIGS. 4A, 4B, 4C, and 4D are exploded views showing various examples of the arrangement and configuration of the first and second diffuser vanes V1, V2. In all figures, the upper side is the pump side, and the lower side is the discharge side.

FIG. 4A shows the first diffuser vane V
1 shows that the first and second diffuser vanes V2 are arranged in a line as in the conventional example. FIG. 4 (B) shows the first
The diffuser vane V1 and the second diffuser vane V2 are displaced from each other.

FIG. 4C shows that the intermediate vane M1 is provided at a position deviated from the middle of the second diffuser vane V2. FIG. 3D shows an example in which the intermediate vane is provided in the middle of the second diffuser vane V2. Thus, in the present invention, the configuration of the second diffuser vane V2 can be changed in various modes.

Therefore, in the embodiment of FIG. 2, the second diffuser casing, the second diffuser vane, the second diffuser vane,
The unit consisting of the central part can be changed in various ways, and optimal efficiency can be obtained.

Although the two embodiments of the present invention have been described above, in addition to the above embodiments, the first and second central portions are integrated, and the second diffuser casing and the second diffuser vane are integrated. In this case, the second diffuser vane and the central portion may be formed separately. Other combinations can be implemented within the scope of the present invention.

[0031]

As described above, according to the present invention, the following excellent effects can be obtained. (A) The flow path of the low specific speed pump can be easily maintained. (B) The arrangement on the downstream side of the diffuser vane can be changed. (C) Disassembly and assembly are easy and maintenance is easy.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention.

FIG. 2 is a sectional view showing a second embodiment of the present invention.

FIG. 3 is a sectional view showing a third embodiment of the present invention.

FIG. 4 is a development view showing various arrangements of a first diffuser vane and a second diffuser vane in (A), (B), (C), and (D), respectively.

FIG. 5 is a perspective view showing a conventional diffuser device without a casing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Inlet pipe 3, 3a ... Bell mouth 8, 31 ... 1st diffuser casing 15 ... Impeller 16 ... Diffuser vane 17 ... Central part 23 ... Joining surface 24 , 34 ... second diffuser casing 26 ... outlet pipe 28 ... adjusting means 29 ... tie rod 32 ... first diffuser vane 33 ... first central part 35 ... 2 diffuser vanes 36... Second central portion 37... Joining surfaces 41 and 42... Flanges 43.

Claims (2)

[Claims] 1. A diffuser device for a pump having an inflow port on the upstream side, an impeller provided therein, and a downstream side connected to an outlet pipe, wherein the diffuser is provided radially outward of the flow path. A diffuser device for a pump, comprising a first diffuser casing and a second diffuser casing in which a casing is divided in an axial direction and engages at a joint surface, and the casings are fixed to each other. 2. A first diffuser vane is provided radially inward of the first diffuser casing, a first central portion is provided radially inward of the first diffuser vane, and a second diffuser casing is provided. 2. A second diffuser vane separate from the first diffuser vane is provided radially inward of the first diffuser vane, and a second central portion is provided radially inward of the second diffuser vane. Pump diffuser device.