JP2598598Y2 - Sewage pump - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sewage pump used for pumping sewage in a sewage treatment facility or the like.

[0002]

2. Description of the Related Art As a conventional sewage pump used in a sewage treatment facility, there is a vertical mixed flow pump as shown in FIG. In FIG. 6, a discharge bowl 2 and a suction casing 3 are provided at a lower end side of a water pump 1. A main shaft 5 is provided inside the pumping pipe 1 by being supported by a submerged bearing 4, and an upper end of the main shaft 5 is connected to a driving device (not shown), and an impeller 6 is provided at a lower end. I have. Further, fixed blades 8 are provided on the inner surface of the discharge bowl 2.

In this configuration, an impeller 6 is rotationally driven by a driving device (not shown) via a main shaft 5 to discharge sewage 9 sucked from a suction casing 3 and discharge from a bowl 2 to a pumping pipe 1. The sewage 9 is pumped through the pumping pipe 1.

As a sewage pump, there is a horizontal-axis mixed flow pump as shown in FIG. 7, the discharge bowl 21 is composed of an upper casing 21a and a lower casing 21b, and is provided with a suction casing 22 connected to the upstream side of the discharge bowl 21. Further, the suction casing 22
The guide blades 23 are provided on the inner surface of the discharge bowl 21, and the fixed blades 24 are provided on the inner surface of the discharge bowl 21. And
Suction casing 2 penetrating through the side wall of suction casing 22
2 and the discharge bowl 21, the base end of the main shaft 25 is connected to a driving device (not shown), and an impeller 27 is attached to the tip end of the main shaft 25 supported by a submerged bearing 26. Is provided.

In this configuration, an impeller 27 is rotationally driven via a main shaft 25 by a driving device (not shown),
The sewage 28 sucked from the suction casing 22 is discharged and discharged from the bowl 21 to a downstream pipe (not shown) to pump the sewage 28.

[0006]

However, the sewage treated by the vertical axial flow pump and the horizontal axial mixed flow pump described above contains foreign matter such as fibrous waste, and the foreign matter is contained together with the waste water in the internal flow path of the casing. Flows as a swirling flow, and moves to the inner peripheral surface side of the casing by centrifugal force. Therefore, FIG.
As shown in FIG. 2, when the vertical axial pump is taken as an example, the foreign matter A bites into the sliding portion 6a between the suction casing 3 and the impeller 6, and the impeller 6 or the suction casing 3 is damaged or overloaded. There was a problem that the drive device tripped.

The present invention solves the above-mentioned problems, and provides a sewage pump capable of facilitating passage of foreign matter between an impeller and a casing, and preventing damage to the pump and tripping of a drive device due to foreign matter being caught. The purpose is to:

[0008]

In order to solve the above-mentioned problems, a sewage pump according to the present invention has a casing having a concentric inner peripheral surface disposed around a main shaft, and the casing is provided around the axis of the main shaft in the casing. Is provided so that the edge of the impeller blade facing the inner peripheral surface of the casing is separated from the inner peripheral surface of the casing toward the outlet side , and
On the inner peripheral surface of the casing facing the edge, the inlet side of the impeller
From the inlet to the exit side
It is formed deeper toward the side .

[0009]

[0010]

According to the above construction, the driven fluid sucked into the casing by the rotation of the impeller flows in the casing as a swirling flow, and foreign matters contained in the driven fluid receive centrifugal force by the swirling flow. It moves to the inner peripheral surface side of the casing.

At this time, the foreign matter that has entered between the edge of the blade and the casing easily moves to the exit side of the impeller because the edge of the blade is more distant from the inner peripheral surface of the casing toward the outlet side. , And foreign matter passes through quickly.

Further, by forming the groove deeper toward the inlet side of the impeller, foreign matter can be easily guided into the groove at the inlet side of the impeller, thereby preventing the foreign matter from being caught and ensuring smooth passage.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a main part of a vertical axial flow pump. In FIG. 1, a casing 31 forms a flow path of sewage which is a driven fluid 32, and an inner peripheral surface thereof has a main shaft 33.
And concentric with. A main shaft 33 is provided in the casing 31.
An impeller 34 is arranged by keying at the end of the main shaft 33, and the impeller 34 rotates around the axis of the main shaft 33. Also, the spindle 3
A driving device (not shown) is connected to the base end side of 3.
Further, the impeller 34 is shaped such that the edge 35a of each blade 35 is separated from the inner peripheral surface 31a of the casing 31 toward the outlet side.

The edge 3 of each blade 35 of the impeller 34
A plurality of grooves 36 extending from the inlet side to the outlet side of the impeller 34 are provided in the inner peripheral surface 31a of the casing 31 facing the 5a, and the shape of the grooves 36 may be a U-shaped cross section or an arc shape. As shown in FIG. 2, it is desirable that this groove be formed deeper toward the entrance side of the impeller 34.

As shown in FIG. 3, the driven fluid 32 in the casing 31 has an absolute velocity V obtained by synthesizing a circumferential velocity u along a rotational direction of the impeller 34 and a relative velocity c. Flows with For this reason,
As shown in FIG. 4, it is desirable that the groove 36 be formed along an absolute speed direction Vf defined by the circumferential speed direction uf and the relative speed direction cf due to the characteristics of the impeller 34. In this embodiment, the case of the vertical axial pump is shown. However, in the horizontal mixed flow pump, the groove provided in the lower casing is formed deeper.

FIG. 5 shows a better shape of the groove 36. In FIG. 5, the groove 36 has side walls 36a, 3a.
6b is inclined in the direction opposite to the rotation direction of the impeller 34, and an opening edge formed by the side wall surface 36a located on the lower side in the rotation direction of the impeller 34 and the inner peripheral surface 31a of the casing 31 36c forms an acute angle.

The operation of the above configuration will be described below.
The impeller 3 is rotated via a main shaft 33 by a rotating device (not shown).
4 is driven to rotate, and the driven fluid 32 is sucked into the casing 31 by the rotation of the impeller 34. The sucked driven fluid 32 flows in the casing 31 as a swirling flow,
The foreign matter A contained in the driven fluid 32 receives centrifugal force due to the swirling flow and moves to the inner peripheral surface 31a side of the casing 31.

At this time, the foreign matter A entering between the edge 35a of the blade 35 and the inner peripheral surface 31a of the casing 31 is separated from the inner peripheral surface 31a of the casing 31 as the edge 35a of the blade 35 is closer to the outlet. Therefore, it easily moves to the exit side of the impeller 34, and the foreign matter A quickly passes.

Further, the foreign matter A flows into the groove 36,
And passes through the impeller 34. Therefore, the impeller 3
No foreign matter A is caught between the edge 35a of each blade 35 and the inner peripheral surface 31a of the casing 31, and smooth rotation of the impeller 34 can be ensured. Moreover, by forming the groove 36 deeper toward the entrance side of the impeller 34, the foreign matter A can be easily guided to the groove 36 at the entrance side of the impeller 34, thereby preventing the foreign matter A from being bitten and smoothly passing. Can be guaranteed.

Since each groove 36 is formed along the direction of the absolute velocity of the driven fluid 32, the foreign matter A flowing into the groove 36 flows quickly. Further, the groove 36 is
And the opening edge 36c of the groove 36 forms an acute edge, so that the foreign matter A can be easily guided into the groove 36, and the blade 35 and the opening edge 36
c can be cut by the edge of the opening edge portion 36c to make the foreign matter A finer, and the foreign matter A can be passed more quickly.

[0021]

As described above, according to the present invention, the edge of the blade of the impeller facing the inner peripheral surface of the casing is formed so as to be more distant from the inner peripheral surface of the casing toward the outlet side. Foreign matter that has entered between the edge of the blade and the casing easily moves to the exit side of the impeller, and the foreign matter quickly passes. By forming the groove provided on the inner peripheral surface of the casing deeper toward the inlet side of the impeller, foreign matter can be easily guided to the groove on the inlet side of the impeller, thereby preventing the foreign matter from being caught and smoothly passing. Can be guaranteed.

[Brief description of the drawings]

FIG. 1 is an enlarged view of a main part of a vertical axial pump according to an embodiment of the present invention.

FIG. 2 is an enlarged view of a main part of a vertical axial flow pump according to another embodiment of the present invention.

FIG. 3 is a schematic view of an impeller in a vertical axial pump.

FIG. 4 is a development view showing a relationship between a blade and a groove in still another embodiment of the present invention.

FIG. 5 is a cross-sectional view illustrating a shape of a groove according to still another embodiment of the present invention.

FIG. 6 is a cross-sectional view of a conventional vertical axial pump.

FIG. 7 is a sectional view of a conventional horizontal-axis mixed flow pump.

FIG. 8 is an enlarged view of a main part of a conventional vertical axial flow pump.

[Explanation of symbols]

 Reference Signs List 31 casing 31a inner peripheral surface 32 driven fluid 33 main shaft 34 impeller 35 blade 35a edge 36 groove

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F04D 29/18-29/38

Claims (1)

(57) [Scope of request for utility model registration] 1. A casing that forms a concentric inner peripheral surface around a main shaft, an impeller that rotates around the axis of the main shaft is provided in the casing, and an impeller that faces the inner peripheral surface of the casing is provided. The blade edge is formed so as to be more distant from the inner peripheral surface of the casing toward the outlet side, and faces the blade edge of the impeller.
From the inlet side to the outlet side of the impeller
A plurality of grooves are provided, and the grooves are formed deeper toward the impeller entrance.
A sewage pump characterized by being formed .