JPH0583755B2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to an impeller for a centrifugal pump.

(Prior art) The types of impellers used in centrifugal pumps include:
There are closed types that have side plates covering the front and rear of the blades, and open types that have side plates only on the back of the blades.
The latter open-type impeller, which is easy to mold, is used for small-sized, small-head pumps.

On the other hand, among the open-type impellers mentioned above, there are flat blade types in which the blades provided on the front side of the side plate have the same width from the suction side to the discharge side, and tapered blade types in which the width gradually decreases toward the discharge side. The latter type is designed to have the same cross-sectional area of the blade passage from the suction side to the discharge side, so it has less flow resistance in the blade passage than the former type and has higher pump efficiency. has been done.

By the way, the above-mentioned open type impeller is structurally configured so that one side of the blade passage is divided by the opposing surface of the casing. If the gap is too large, liquid leakage will increase and the volumetric efficiency, which is one type of pump efficiency, will decrease. It is formed perpendicularly to the axis b and has a blade c protruding from its front surface.
If the blade c provided on the side plate a is a tapered blade, the opposing surface d of the casing must also be shaped to match the taper of the blade c, which makes processing extremely difficult, and the gap between the leading edge of the blade and the casing In order to make the gap uniform from the suction side to the discharge side, strict machining accuracy is required, which inevitably increases manufacturing costs.

(Purpose) The present invention was made in view of these problems, and its purpose is to provide a new centrifugal pump that is easy to process and manage gaps, and can maximize pump efficiency. Our goal is to provide impellers.

(Means for Achieving the Object) That is, the present invention provides an impeller for achieving the object, in which the side plate of an open type impeller is formed into an umbrella shape with the outer peripheral edge deviated toward the suction side, and the front surface of the side plate is In addition, a blade whose leading edge is perpendicular to the axis is integrally fixed.

(Example) The details of the present invention will be described below based on illustrated examples.

1 and 2 show an impeller that is an embodiment of the present invention. This impeller 1 has a large number of blades 2 extending spirally from the suction side at the center toward the discharge side at the outer periphery. and a disk-shaped side plate 3 that supports the trailing edges of these blades 2 and defines one side of the flow path formed between each blade 2. The outer periphery of the boss portion 4, which forms the connecting portion with the drive shaft 5, is formed into an umbrella shape that protrudes forward, that is, toward the suction port 8 side (FIG. 2), and is integrally formed on the front surface of the side plate 3. Each of the blades 2 protruding from the blades 2 is formed in a tapered shape such that the width gradually decreases toward the outer periphery so that the cross-sectional area of the flow path between the blades 2 is approximately equal from the suction port 8 side to the discharge side. , each of these front edges 2a... are formed perpendicular to the axis.

FIG. 2 shows a centrifugal pump incorporating the impeller 1 formed in this way.A front casing 7 covering the front surface of the impeller 1 is provided with a suction port 8 and a discharge port 9. Opposing surfaces 10 along the front edges 2a of the blades 2 are formed as planes perpendicular to the axis, and the rear edges 11 are formed on the rear casing 1.
By joining the front edge 13 of the blade 2 to the front edge 13 of the blade 2 as a reference, the gap δ created between the front edge 2a of the blade 2 and the opposing surface 10 can be made uniform from the suction port 8 side to the discharge side. 14 is the motor, and 15 is the inner surface of the rear casing 12 and the impeller 1.
A mechanical seal interposed between the rear end and the rear end is shown.

Therefore, after forming the impeller 1 and the front casing 7 by casting or the like, if the front edge 2a and the facing surface 10 of the blade 2 are respectively ground flat using a processing machine, the blade 2 will be flat when assembled as a pump. There is a minimum necessary gap δ between the leading edge 2a and the opposing surface 10.
is formed uniformly over the entire surface.

Note that since the side plate 3 of the impeller 1 is umbrella-shaped, the gap between it and the rear casing 12 is large;
Since the back of the is a sealed chamber, the volumetric efficiency will not be reduced.

(Effects) As described above, according to the present invention, the side plate of the impeller is formed into an umbrella shape, and the tapered blade is integrally fixed to the front surface of the side plate so that the leading edge is perpendicular to the axis. Therefore, not only is it extremely easy to process and control the dimensions of the opposing parts of the impeller and casing, but also the gap between them can be made uniform over the entire surface and as small as possible. The efficiency of seed pumps can be greatly improved.

[Brief explanation of the drawing]

Figures 1a and b are side and front views of an impeller showing an embodiment of the present invention, Figure 2 is a sectional view of a centrifugal pump equipped with this impeller, and Figure 3 is a sectional view of a conventional centrifugal pump. It is a diagram. 1... Impeller, 2... Blade, 2a... Leading edge, 3
... Side plate, 7 ... Front casing, 10 ... Opposing surface, 12 ... Rear casing.

Claims (1)

[Claims] 1. A blade in which the side plate of an open type impeller is formed into an umbrella shape with the outer peripheral edge biased toward the suction side, and a blade whose leading edge is perpendicular to the axis is integrally fixed to the front surface of the side plate. car.