JPH0710495U - Sewage pump - Google Patents

Abstract

(57) [Summary] [Structure] A plurality of grooves 36 extending from the inlet side to the outlet side of the impeller are provided on the inner peripheral surface of the casing 31 facing the edge 35a of the impeller 35 provided on the impeller. Side wall surface 3 of groove 36
6a and 36b are formed so as to be inclined in a direction opposite to the rotation direction of the impeller, and an acute edge is formed at the opening edge portion 36c of the groove located on the lower side in the rotation direction of the impeller. [Effect] The foreign matter can be easily guided into the groove, and the foreign matter sandwiched between the blade and the opening edge portion can be cut into fine pieces by the edge of the opening edge portion 36c, so that the foreign matter can be quickly passed. it can.

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. 7. In FIG. 7, 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. 8, the discharge bowl 21 is composed of an upper casing 21a and a lower casing 21b, and a suction casing 22 is connected to 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. 9, taking a vertical axial flow pump as an example, foreign matter A is bitten in 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 the main shaft, and an impeller that rotates around the main shaft axis is provided in the casing to provide the impeller. On the inner peripheral surface of the casing facing the edge of the blade provided on the car, multiple grooves running from the inlet side to the outlet side of the blade wheel are provided, and the side wall surface of the groove faces in the direction of rotation of the impeller. It is formed so as to be inclined toward, and a sharp edge is formed at the opening edge of the groove located on the lower side in the rotation direction of the impeller.

[0009]

[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. At this time, the foreign matter contained in the driven fluid receives centrifugal force due to the swirling flow, moves toward the inner peripheral surface of the casing, flows into the groove, flows in the groove, and passes through the impeller. Therefore, foreign matter does not get caught between the edge of each blade of the impeller and the inner peripheral surface of the casing, and smooth rotation of the impeller can be guaranteed.

Moreover, since the groove is opened so as to face each other in the rotation direction of the blade and an acute edge is formed at the opening edge portion of the groove, foreign matter can be easily introduced into the groove, and further, the blade and the opening edge portion can be easily guided. The foreign matter sandwiched between and can be cut into fine pieces by the edge of the opening edge, and the foreign matter can be quickly passed.

[0011]

【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.

A plurality of grooves 36 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, from the inlet side of the impeller 34 toward the outlet side. As shown in FIG. 2, the groove 36 has side wall surfaces 36a and 36b inclined toward the direction opposite to the rotating direction of the impeller 34, and is located on the lower side in the rotating direction of the impeller 34. An opening edge portion 36c formed by the positioned side wall surface 36a and the inner peripheral surface 31a of the casing 31 forms an acute edge.

By the way, as shown in FIG. 3, the driven fluid 32 in the casing 31 has an absolute directional 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 impeller 34. In FIG. 5, the diameter of the impeller 34 becomes smaller toward the outlet side, that is, the edge portion 35a of each blade 35 is separated from the inner peripheral surface 31a of the casing 31 toward the downstream side in the flow direction of the driven fluid 32. It has a unique shape.

FIG. 6 illustrates a better shape combination of impeller 34 and groove 36. In FIG. 6, the groove 36 is formed deeper on the upstream side in the flow direction of the driven fluid 32.

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. .

Then, 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. However, since each groove 36 is formed along the absolute velocity direction of the driven fluid 32, the foreign matter A flowing into the groove 36 flows quickly.

Further, since the groove 36 is opened so as to face in the rotation direction of the blade 35, and the opening edge portion 36 c 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 blade 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.

The edge portion 35 a of the blade 35 is separated from the inner peripheral surface 31 a of the casing 31 toward the downstream side in the flow direction of the driven fluid 32, so that the foreign matter A sandwiched between the blade 35 and the casing 31 is removed. The impeller 34 can be easily moved to the outlet side, and the foreign matter A can be passed through more quickly.

Further, by forming the groove 36 deeper toward the upstream side in the flow direction of the driven fluid 32, it becomes easier to guide the foreign matter A into the groove 36 at the inlet side of the impeller 34, and the foreign matter A is prevented from being bitten. It can prevent and guarantee smooth passage.

[0021]

[Effect of device]

 As described above, according to the present invention, a plurality of grooves are formed on the inner peripheral surface of the casing facing the impeller, the grooves are opened so as to face each other in the rotation direction of the blade, and the opening edge portion of the groove is formed. Since the sharp edges are formed, it is easy to guide foreign matter into the groove, and the foreign matter sandwiched between the blade and the opening edge can be cut by the edge of the opening edge to make it finer. Can be quickly passed.

[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 a cross-sectional view showing a shape of a groove in the example.

FIG. 3 is a schematic view of an impeller in the same example.

FIG. 4 is a development view showing the relationship between the blade and the casing in the embodiment.

FIG. 5 is an enlarged view of a main part of a vertical axial flow pump according to another embodiment of the present invention.

FIG. 6 is an enlarged view of a main part of a vertical axial flow pump according to still another embodiment of the present invention.

FIG. 7 is a sectional view of a conventional vertical axial pump.

FIG. 8 is a cross-sectional view of a conventional horizontal axis mixed flow pump.

FIG. 9 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 (1)

[Scope of utility model registration request] 1. A casing which forms a concentric inner peripheral surface is arranged around a main shaft, and an impeller that rotates around the axial center of the main shaft is provided inside the casing, facing the edge of the blade provided on the impeller. The inner peripheral surface of the casing is provided with a plurality of grooves from the inlet side to the outlet side of the impeller, and the side wall surfaces of the grooves are formed by inclining toward the direction opposite to the rotation direction of the impeller. A sewage pump characterized in that an acute edge is formed at an opening edge portion of a groove located on the lower side in the rotation direction.