JP4888871B2 - Air lock prevention structure for submersible pumps - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an air lock prevention structure for a submersible pump used in a manhole or the like.
[0002]
[Prior art and its problems]
In general, this type of submersible pump has a large clearance between the upper surface of the suction cover and the lower edge 109e of the blade plate, as shown in FIG. A boundary line 102 </ b> L formed between the inner periphery of the upper edge and the lower edge of the blade plate 109 e is formed horizontally at substantially the same height, and the entire impeller 104 is completely accommodated in the impeller chamber 105. Thus, since the vane plate lower edge 109e and the ceiling 107e of the discharge port 107 are substantially at the same height, there is no air escape and an air pocket is generated in the impeller chamber 105.
[0003]
In such a structure, the pumping of water takes time due to the accumulation of air in the impeller chamber 105, and particularly when the operation is resumed after the pump is stopped, the air in the impeller chamber 105 is not discharged even if the impeller 104 rotates. 104 is not submerged, and a so-called air lock phenomenon occurs, and pumping becomes impossible.
[0004]
As a countermeasure for preventing air lock, an air vent hole (not shown) that passes from the impeller chamber 105 to the upper side of the pump casing 102 is usually provided. However, since water also flows out from the air vent hole during the pump operation, there is a disadvantage that the pump discharge amount is reduced accordingly. Even if a valve body is attached to the air vent hole for the purpose of preventing the outflow of water, if the pump is used in sewage, foreign matter will clog the air vent hole and the air inside the impeller chamber 105 Will not be able to be discharged, and an air lock will occur when operation is resumed.
[0005]
OBJECT OF THE INVENTION
An object of the present invention is to provide an air lock prevention structure for a submersible pump that prevents air lock without reducing the pump discharge amount during operation and does not impair its function even when used in sewage. It is in.
[0006]
[Structure of the invention]
In the air lock prevention structure of the submersible pump according to claim 1 of the present invention, the pump casing connected to the lower side of the rigid motor and having the vertical axis is fitted to the lower end of the motor shaft. An impeller chamber for accommodating a car, and a spiral chamber having a suction port in the center of the lower surface and a discharge port in the lateral direction immediately below the impeller chamber, and the spiral chamber parallel to the lower edge of the impeller blade plate The lower surface of the discharge port is provided horizontally and the ceiling of the discharge port is located higher than the lower edge of the vane blade plate and lower than the lower surface of the shroud, and the inner peripheral lower edge of the impeller chamber and the upper peripheral inner periphery of the spiral chamber boundary formed between the, in the winding of the beginning of the spiral chamber is in substantially contour position and the vane lower edge, forming the upstream gradient shape that rises to the ceiling position of approximately the discharge port in the winding of the terminal portion When the pump is stopped, keep the lower half of the slats submerged. It was configured to cause.
[0007]
Moreover, in the air lock prevention structure of the submersible pump according to claim 2 according to the present invention, the boundary line formed between the inner peripheral lower edge of the impeller chamber and the upper peripheral inner periphery of the spiral chamber is the spiral chamber. from beginning of winding to the intermediate portion is formed in a substantially contour position and the vane lower edge, that is formed on the upstream gradient shape from the intermediate portion to the winding of the end portion rises to almost ceiling position of the discharge port It is characterized by.
[0008]
【Example】
The embodiment will be described below with reference to FIGS.
[0009]
1 is a vertical motor, 2 is a pump casing which is connected to the lower side of the vertical motor 1 and has an axis in the vertical direction. The impeller accommodates an impeller 4 fitted to the leading end of the motor shaft 3. A chamber 5 and a spiral chamber 8 having a suction port 6 in the center of the lower surface and a discharge port 7 in the lateral direction immediately below the impeller chamber 5, and spirally parallel to the lower edge 9 e of the blade plate of the impeller 4. An opposing space is provided with the lower surface of the chamber 8 being horizontal, and the ceiling 7c of the discharge port 7 is higher than the lower edge 9e of the vane plate and lower than the shroud surface 10u, and the inner peripheral lower edge of the impeller chamber 5 and the spiral chamber The boundary line 2L formed between the upper edge and the inner periphery of the upper edge 8 is substantially flush with the lower edge 9e of the blade at the winding start end 8a of the spiral chamber 8, and is substantially at the discharge port at the winding end 8c. up to 7 of the ceiling position 7c is formed on the upstream gradient shape to increase. As a further desirable form of the boundary line 2L, the winding chamber 8 is held from the winding start end portion 8a to the intermediate portion 8b at substantially the same height position as the vane lower edge 9e, and from the intermediate portion 8b to the winding end portion 8c. rises to the ceiling position 7c of the outlet 7 is formed on the upstream gradient shape. The axial dimension of the winding end portion 8c of the spiral chamber 8 is formed larger than the axial dimension of the winding start end portion 8a and becomes deeper in the vicinity of the discharge port 7, and the impeller chamber in the corresponding portion of the spiral chamber 8 is larger. The axial dimension is relatively small, and the impeller chamber 5 is shallow near the discharge port 7. Accordingly, almost the entire blade plate 9 is accommodated in the impeller chamber 5 in the vicinity of the winding start end portion 8a, but in the vicinity of the winding end portion 8c, the substantially lower half of the blade plate 9 extends beyond the boundary line 2L and the spiral chamber 8 The blade lower edge 9e is positioned below the ceiling 7c of the discharge port 7.
[0010]
[Action]
Thus, the spiral chamber 8 becomes deep near the discharge port 7 and the lower edge 9e of the blade plate is located below the ceiling 7c of the discharge port 7. Therefore, even when the pump is stopped, the lower half of the blade plate 9 is substantially lower. Since the impeller chamber 5 is shallow in the vicinity of the discharge port 7 and the lower edge of the impeller reaches a position lower than the ceiling 7c of the discharge port 7, Unnecessary air in the chamber 5 is naturally exhausted from the discharge port 7 and does not cause an air lock even when the operation is resumed.
[0011]
【Effect of the invention】
According to the present invention, since unnecessary air in the impeller chamber 5 is naturally exhausted from the discharge port 7, it is not necessary to provide an air vent hole as in the prior art, and without reducing the pump discharge amount during operation. Air lock can be prevented, and even when used in sewage, its function is not impaired.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional side view of an essential part of a submersible pump having a structure of the present invention.
FIG. 2 is a plan view of a pump casing in the structure of the present invention.
FIG. 3 is a longitudinal side view taken along line AA in FIG. 2;
4 is a longitudinal side view taken along line BB in FIG. 2. FIG.
FIG. 5 is a longitudinal sectional side view of a main part of a submersible pump illustrating a conventional structure.
[Explanation of symbols]
First vertical motor 2 pump casing 2L border 3 motor shaft 4 impeller 5 impeller chamber 6 inlet 7 discharge port 7c discharge opening of the ceiling 8 volute 8a winding starting end portion 8b winding intermediate portion 8 c winding terminations 9 Blade 9e Blade lower edge 10u Shroud bottom

Claims (2)

A pump casing connected to the lower side of the saddle type motor and having an axis in the vertical direction has an impeller chamber that houses an impeller fitted to the leading end of the motor shaft, and a center of the lower surface immediately below the impeller chamber. A spiral chamber having a suction port in the horizontal direction and a discharge port in the lateral direction, and provided with a facing space with the lower surface of the spiral chamber parallel to the lower edge of the impeller blade plate, the ceiling of the discharge port being the blade plate It is located at a position higher than the lower edge and lower than the lower surface of the shroud, and a boundary line formed between the inner peripheral lower edge of the impeller chamber and the upper peripheral inner periphery of the spiral chamber is a blade at the start of the spiral chamber. located approximately contour position the plate lower edge, to form the upstream gradient shape that rises to the ceiling position of approximately the discharge port in the winding end portion, holding the substantially lower half of the slats in the submerged state at the time of pump stop Air lock prevention structure for submersible pumps The boundary line formed between the inner peripheral lower edge of the impeller chamber and the upper peripheral inner periphery of the spiral chamber is formed at almost the same height as the lower edge of the vane plate from the start to the middle of the spiral chamber. is characterized in that it is formed in the upstream gradient shape rises to almost ceiling position of the discharge port from the intermediate portion toward the winding terminal end, airlock preventing structure in the water pump according to claim 1, wherein.

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