JPS597596Y2 - centrifugal pump - Google Patents

Description

[Detailed Description of the Invention] Conventionally, centrifugal pumps using a closed-type impeller having an S-shaped passage groove have been widely used as special liquid pumps for paper manufacturing, sewage, and filth.

In this case, the impeller has two or three blades in order to avoid clogging with foreign matter, and the back side of the water passage inside the impeller is hollow with the front and outer periphery open for the purpose of reducing weight.

However, as shown by the arrows in Figures 1 and 2, during operation, the high-pressure liquid sent to the outer periphery of the impeller in the vortex chamber enters the cavity, which disrupts the liquid flow and reduces pump efficiency. Not only that, it also generates vibration and noise, and due to the proximity of the infiltrated high-pressure liquid to the low-pressure suction port, the backflow from that part further reduces pump efficiency, and the backflow water causes wear. As a result, the decrease in pump efficiency increases.

Furthermore, the impeller itself had many defects, such as difficulty in achieving static balance due to uneven weight distribution due to the arrangement of the blades and front shroud.

In view of the above-mentioned circumstances, the present invention forms a blade integrally with the shroud by making the back side of an S-shaped passage groove into a hollow shape with the front and outer peripheral parts open, and the hollow part is made of resin, rubber, etc. In addition to filling with a non-metal with a low specific gravity, auxiliary vanes are provided protruding from the filling part and the outer surface of the front shroud to bring them into close contact with the side wall of the pump casing, preventing unnecessary disturbance in the vortex chamber and backflow to the suction side, thereby improving pump efficiency. The invention relates to centrifugal pumps aimed at improving performance and increasing pump life.

In detail regarding the embodiment shown in the figure, 1 is a pump casing, 2 is a pump casing;
is a two-blade closed type impeller with an S-shaped passage groove, and the back side of the water passage inside the impeller is hollow with the front and outer periphery open, and the blade part 3 is integrally formed with a shroud described later using a metal material. A suitable number of back blades 5 are provided on the back surface of the rear shroud 4, which is shaped like a disk, for the purpose of balancing the axial thrust, reducing pressure on the shaft seal part, and maintaining static balance, and are connected to the pump casing 1. The bearing fitting 6 is placed close to the wall surface.

Further, the front shroud 7 of the impeller 2 is shaped so as to cover only the portion facing the water passage inside the impeller, and the hollow portion on the back side of the water passage inside the impeller is made of resin or rubber so as to form the same surface as the front shroud 7. It is filled with a non-metallic material 8 having a small specific gravity, and auxiliary blades 9, 1 of an appropriate size and height are provided on the filling part 8 and the outer surface of the front cover 7.
0 is provided in a protruding manner so as to face the side wall of the pump casing 1 on the side of the suction port 11 with a slight gap.

12 is a mouth ring portion, 13 is a pump shaft, and 14 is a shaft seal.

The auxiliary blades 9 are formed integrally with the non-metallic material 8, and the auxiliary blades 10 are formed integrally with the front shroud 7 from metal. The auxiliary vane 10 may be formed at the same time as the groove is filled with a non-metallic material.As described above, in a pump of the present invention, the vane formed of metal has an open front surface and an outer circumference. Since the metal part is reduced in the hollow shape and the hollow part is filled with a non-metallic material with low specific gravity, it is possible to largely avoid bias in weight distribution compared to an impeller with blades formed only of metal. Weight can also be reduced.

However, during operation, the overall weight of the impeller is reduced, so even if slight wear occurs, there is less negative impact on the bearing due to unbalance, and the cavity on the back side of the water flow path is filled with non-metallic material. Therefore, the high-pressure liquid discharged into the volute chamber does not flow back into the impeller, and the provision of auxiliary vanes on the outer surface of the front shroud, including the filling section, prevents the high-pressure liquid around the impeller from being sucked in. Since it is possible to balance the pressure without flowing back to the mouth ring part of the mouth, it is possible to prevent vibration and noise, prevent wear of the mouth ring part, and prevent a decrease in efficiency.

Furthermore, by mixing an appropriate amount of metal powder into the non-metallic material to be filled, the weight distribution can be adjusted and an impeller with good static balance can be obtained, and many other effects can be produced.

[Brief explanation of the drawing]

1 and 2 are explanatory diagrams showing an example of a conventional pump. FIG. 1 is a cross-sectional view of the pump, and FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1. Figures 3 and 4 show an embodiment of the present invention. Figure 3 is a cross-sectional view of the pump taken only at the suction port of the impeller, and Figure 4 is a cross-sectional view taken along line B-B in Figure 3. . In the figure, 1 is the pump casing, 2 is the impeller, 3 is the blade, 4 is the rear shroud, 5 is the back blade, 6 is the bearing fitting, 7
8 indicates a front shroud, 8 indicates a non-metallic filler, 9 and 10 indicate auxiliary blades, and 12 indicates a mouth ring portion.

Claims (1)

[Scope of utility model registration request] In a closed type impeller having an S-shaped passage groove, etc., the back side of the water passage inside the impeller has a hollow shape with only the front and outer periphery open, and the blade part is formed integrally with the shroud using a metal material, and the hollow The centrifugal pump is characterized in that the part is filled with a non-metallic material with low specific gravity such as resin or rubber, and auxiliary vanes are provided protruding from the filled part and the outer surface of the front shroud, facing the side wall of the pump casing on the suction port side with a slight gap. pump.