JPH0710496U - Sewage pump - Google Patents

Abstract

(57) [Summary] [Structure] A casing 31 forming a concentric inner peripheral surface 31a is arranged around a main shaft 33. An impeller 34 that rotates around the axis of the main shaft 33 is provided in the casing 31. The edge portion 35a of the blade 35 of the impeller 34 facing the inner peripheral surface 31a of the casing 31 is formed so as to be more distant from the inner peripheral surface 31a of the casing 31 on the outlet side. [Effect] The foreign matter that has entered between the edge portion 35a of the blade 35 and the casing 31 easily moves to the outlet side of the impeller 34, and the foreign matter quickly passes.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a sewage pump used for pumping sewage in a sewage treatment facility or the like.

[0002]

[Prior art]

 As a sewage pump used in conventional sewage treatment facilities, there is a vertical mixed flow pump as shown in Fig. 6. In FIG. 6, a discharge bowl 2 and a suction casing 3 are provided on the lower end side of the pumping pipe 1. Further, a main shaft 5 supported by an underwater bearing 4 is provided inside the pumping pipe 1, and an upper end side of the main shaft 5 is connected to a drive device (not shown) and an impeller 6 is provided at a lower end side. ing. Further, fixed blades 8 are provided on the inner surface of the discharge bowl 2.

In this configuration, a driving device (not shown) rotationally drives the impeller 6 via the main shaft 5, discharges the dirty water 9 sucked from the suction casing 3 and discharges it from the bowl 2 to the pump pipe 1, Sewage 9 is pumped through the pumping pipe 1.

Further, as a sewage pump, there is a horizontal axis mixed flow pump as shown in FIG. In FIG. 7, the discharge bowl 21 is composed of an upper casing 21a and a lower casing 21b, and a suction casing 22 is provided in connection with the upstream side of the discharge bowl 21. Furthermore, a guide blade 23 is provided on the inner side surface of the suction casing 22, and a fixed blade 24 is provided on the inner side surface of the discharge bowl 21. Then, the main shaft 25 is inserted through the side wall of the suction casing 22 into the suction casing 22 and the discharge bowl 21, and the base end side of the main shaft 25 is connected to a drive device (not shown) and the underwater bearing is used. An impeller 27 is provided on the tip side of the main shaft 25 supported by 26.

In this configuration, a driving device (not shown) rotationally drives the impeller 27 via the main shaft 25 to discharge the dirty water 28 sucked from the suction casing 22 and to provide a pipe (downstream) from the bowl 21. (Not shown) to discharge the dirty water 28.

[0006]

[Problems to be solved by the device]

 However, the sewage handled by the vertical axis pump and horizontal axis diagonal flow pump described above contains foreign matter such as fibrous dust, and this foreign matter flows with the sewage into a swirling flow in the internal flow path of the casing, causing centrifugal separation. It moves to the inner peripheral surface side of the casing by force. Therefore, as shown in FIG. 8, a vertical axial pump will be described as an example. Foreign matter A is bitten 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 there was a problem that the drive device trips due to overload.

The present invention solves the above problems, and provides a sewage pump that facilitates the passage of foreign matter between the impeller and the casing, and prevents pump damage and tripping of the drive unit due to foreign matter being caught. The purpose is to do.

[0008]

[Means for Solving the Problems]

 In order to solve the above problems, the wastewater pump of the present invention has a casing that forms a concentric inner peripheral surface around a main shaft, and an impeller that rotates around the main shaft axis is provided in the casing. The edge of the blade of the impeller facing the inner peripheral surface of is formed so as to be separated from the inner peripheral surface of the casing toward the outlet side.

Further, a plurality of grooves extending from the inlet side to the outlet side of the impeller are provided on the inner peripheral surface of the casing facing the edge of the impeller blades, and the grooves are formed deeper toward the inlet side of the impeller. Is.

[0010]

[Action]

 With the above configuration, the driven fluid sucked into the casing by the rotation of the impeller becomes a swirling flow and flows in the casing, and the foreign matter contained in the driven fluid receives a centrifugal force due to the swirling flow to cause the inside of the casing to move. Move to the peripheral side.

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

Further, by forming the groove deeper toward the entrance side of the impeller, foreign matter can be easily guided to the groove at the entrance side of the impeller, preventing foreign matter from being bitten and ensuring smooth passage. it can.

[0013]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows the main part of a vertical axial flow pump. In FIG. 1, a casing 31 forms a flow path for sewage that is a driven fluid 32, and its inner peripheral surface is concentric with the main shaft 33. An impeller 34 is arranged in the casing 31 by keying it to the tip of the main shaft 33, and the fan wheel 34 rotates around the axis of the main shaft 33. Further, a drive device (not shown) is connected to the base end side of the main shaft 33. Further, the impeller 34 is shaped such that the edge portion 35a of each blade 35 is separated from the inner peripheral surface 31a of the casing 31 toward the outlet side.

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

By the way, as shown in FIG. 3, the driven fluid 32 in the casing 31 has an absolute direction velocity V obtained by combining a circumferential velocity u along the rotation direction of the impeller 34 and a relative velocity c. Flows with. Therefore, as shown in FIG. 4, it is desirable that the groove 36 be formed along the absolute velocity direction Vf defined by the circumferential velocity direction uf and the relative velocity direction cf due to the characteristics of the impeller 34. Further, the present embodiment shows the case of the vertical axial flow pump, but in the horizontal axial 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 is inclined so that the side wall surfaces 36a and 36b thereof are opposed to each other in the rotation direction of the impeller 34, and the side wall surface 36a and the casing located on the lower side in the rotation direction of the impeller 34. An opening edge portion 36c formed by the inner peripheral surface 31a of the ring 31 forms an acute angle.

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

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

Further, the foreign matter A flows into the groove 36, passes through the groove 36, and passes through the impeller 34. Therefore, the foreign matter A does not bite between the edge portion 35a of each blade 35 of the impeller 34 and the inner peripheral surface 31a of the casing 31, and the smooth rotation of the impeller 34 can be guaranteed. Moreover, by forming the groove 36 deeper toward the entrance side of the impeller 34, the foreign material A can be easily guided to the groove 36 at the entrance side of the impeller 34, preventing the foreign material A from being bitten and smoothly passing through. Can be guaranteed.

Since each groove 36 is formed along the absolute velocity direction of the driven fluid 32, the foreign substance A flowing into the groove 36 flows quickly. Further, since the groove 36 is opened so as to face the rotating direction of the blade 35, and the opening edge portion 36c of the groove 36 forms a sharp edge, it is easy to guide the foreign matter A into the groove 36, and The foreign material A sandwiched between the gap 35 and the opening edge portion 36c can be cut into fine pieces by the edge of the opening edge portion 36c, and the foreign material A can be passed through more quickly.

[0021]

[Effect of device]

 As described above, according to the present invention, the blade edge of the impeller facing the inner peripheral surface of the casing is formed so as to be separated from the inner peripheral surface of the casing toward the outlet side. The foreign matter that has entered between the edge and the casing easily moves to the outlet side of the impeller, and the foreign matter passes quickly. By forming the groove 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 at the inlet side of the impeller, preventing foreign matter from being bitten and smoothly passing through. Can be guaranteed.

[Brief description of drawings]

FIG. 1 is an enlarged view of a main part of a vertical axial flow pump showing 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 diagram of an impeller in a vertical axial flow pump.

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

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

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

FIG. 7 is a cross-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]

 31 casing 31a inner peripheral surface 32 driven fluid 33 main shaft 34 impeller 35 blades 35a edge 36 groove

Claims (2)

[Scope of utility model registration request] 1. A casing, which forms a concentric inner peripheral surface around a main shaft, is arranged, and an impeller that rotates around the shaft center of the main shaft is provided in the casing, and an impeller facing the inner peripheral surface of the casing is provided. A sewage pump characterized in that the blade edges are formed so as to be more distant from the inner peripheral surface of the casing toward the outlet side. 2. A plurality of grooves extending from the inlet side to the outlet side of the impeller are provided on the inner peripheral surface of the casing facing the edge of the impeller blade, and the grooves are formed deeper toward the inlet side of the impeller. The sewage pump according to claim 1, characterized in that.