JPS6119835B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pump having a single-plate conical screw vane blade.

Pumps for transferring sewage, filth, pulp liquid, etc. are required to be non-obstructive pumps that do not become clogged or caught by foreign matter such as solid matter or fibrous substances. Some pumps of this type are equipped with an impeller having one or a few blades.

FIG. 4 is an example of a conventional pump having a small number of blades. In the figure, an impeller 1 having blades 2 is supported by a pump casing 4 so as to rotate about a center line 3 shown in the figure. pump casing 4
There is a gap δ shown in the figure between the blade 2 and the edge of the blade 2.

FIG. 5 is a partial front view of the impeller shown in FIG. 4.
The blade tip 5 of the blade 2 is located at a position set back by an angle β from the direction of the radiation from the center line 3. In such an example, the fourth
As shown by the arrow in the figure, the liquid containing solid matter flows, so even if solid matter enters the gap δ, it can pass through because the gap δ is large. However, with this structure, leakage loss of liquid is large, and therefore pump efficiency is reduced.

Another conventional example includes a pump casing whose generatrix is a straight line and a curved conical rotating surface, and an impeller whose outer circumferential rotating surface of the screw vane is the same conical rotating surface (Japanese Patent Publication No. 43-15006 Publication No.). This known pump includes a conical first hub and a second hub that is angularly offset from the axis of the first hub.
An impeller with a single continuous helical threaded plate of substantially constant thickness surrounding a second hub and extending axially upstream from the second off-axis hub is provided with a gap in the casing. A small amount is paid. In this type of pump, pump performance can be improved by having the screw vanes come out before the first hub.

The invention related to Japanese Patent Application No. 56-66035, ``Single-blade impeller pump,'' consists of a ``pump casing with a conical rotating surface between the suction port and the discharge casing, and an outer circumferential rotating surface of the pump casing with a conical rotating surface. In a single-blade impeller pump, in which an impeller is rotatably supported in a casing, the impeller is rotatably supported in a casing, and the blade of the conical hub is formed with conical screw blades that are close to each other with a small gap. A single-blade impeller pump in which the blade tip is inclined in a direction in which the front of the blade tip moves forward from a radiation line from the center line of the pump shaft from the root of the blade. Although the efficiency is better than those of the conventional examples, it is not extremely good, and it is necessary to improve the efficiency even further.

The purpose of the invention is to improve the efficiency of single-blade impeller pumps.

The single-blade impeller pump of the present invention has a pump casing with a conical rotating surface between the suction port and the discharge casing, and a conical screw whose outer peripheral rotating surface approaches the conical rotating surface of the pump casing with little clearance. In a single-blade impeller pump in which an impeller whose blades are formed into conical hubs is rotatably supported within a casing, the attachment angle of the blades to the hub is 30 to 60 degrees on the inlet side and 30 to 60 degrees on the outlet side. The blades are inclined from 0 to 40 degrees toward the suction port side from the pump main shaft, and the angle between the blades and the pump main shaft axis gradually decreases from the inlet side to the outlet side.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view including the pump shaft of the present invention. The pump casing 4 is integrally formed with a suction port 6, and has a cone-like shape with the suction port 6 side as the small end and the inner periphery rotated around the pump main shaft 3' with a generatrix of a straight line, a curve, or a combination thereof. Yes, the pump casing 4 has a discharge casing 7
The conical hub 8 of the impeller 1 is attached to the pump main shaft 3', which is fixed and whose axial movement is restrained by the discharge casing 7, rotatably supported and sealed (description will be omitted). It is screwed in so that it is in the tightening direction. The conical hub 8 has a generatrix of a straight line, a curved line, or a rotating curved surface with a combination thereof, and is selected so as to provide an appropriate fluid passage between the conical hub 8 and the pump casing 4.

A screw blade 2 is integrally formed on the conical hub 8. The suction port 6 side of the blade 2 ends near or at the apex of the conical hub 8, from which point the blade tip 5 points toward the outer periphery of the blade 2. The outer periphery of the blade 2 is on a rotating surface centered on the pump main shaft 3', which has a straight line, a curved line, or a generatrix of a combination thereof, which is located at a position with little clearance from the inner circumferential surface of the pump casing 4.

FIG. 2 is an enlarged front view of the center of the tip of the wing 2. The boundary line 9 between the conical hub 8 and the root of the wing 2 ends near the center line 3 (perpendicular to the plane of the paper), and the wing tip 5 extends in the direction in which the wing tip 5 advances from the line 10 from the center line 3. The end 5 has a concave curve that gradually moves away from the radiation 10. When the curvature is large, this may be replaced with a straight line, but it is preferable to use a curved line in which the tangential angle 7 gradually increases as the distance from the center increases, as shown in the figure, so as to direct the flow of fluid toward the center, which will be explained later. The angle β between the center line 3 and the line connecting the center line 3, the intersection 12 of the blade tip 5 and the outer periphery 11 of the blade 2, and the ray 10 is the size of the illustrated example.

FIG. 6 is a front view of the impeller 1 viewed from the suction port side of the blades 2, showing the front shroud side corner of the blades 2. FIG. 7 is a sectional view of the impeller 1 including the center line in FIG. 6.

The 0-a section of the blade tip on the suction port side of the blade 2 in FIG. 6 is the blade 2a in FIG. 7, and the 0-b cross section is the blade 2b, 0.
The -c section is represented by the blade 2c, the 0-d cross section near the discharge port is represented by the blade 2d, and the 0-e cross section is represented by the blade 2e. Wing 2a
Assuming that the thickness of the cross section is t ₁ on the shroud side and t ₂ on the blade root side, t ₁ =t ₂ , that is, it has a flat plate shape.

The mounting angle α between the blade 2 and the conical hub 8, that is, the angle α between the front side of the blade 2 and the center line 3 of the pump main shaft 3' on the plane including the pump main shaft 3' is the angle α between the blade 2 and the center line 3 of the pump main shaft 3'. In the blade 2a, α=30 to 60 degrees, and in the outlet side blade 2e, α=0 to 40 degrees, and the angle α gradually becomes smaller from the inlet side to the outlet side.

In contrast to the above, the above specifications of the blade of the conventional single-blade impeller pump have a blade cross section such that the cross-sectional line of FIG. 6 is shown in FIG _. < _t2 , and the blade attachment angle α=50 to 60 degrees, which is constant from the blade 2a on the inlet side to the blade 2e on the outlet side.

In FIG. 1, when the impeller 1 rotates, fluid containing solids is sucked in, moves through the space of the blades 2 in the pump casing 4, is sent to the discharge casing 7, and is discharged. At this time, as shown in the explanatory view of FIG. 3, the solid matter flows in the direction of the arrow 14 at the blade tip 5. Although the tip of the cone-like hub 8 is shown, it is not actually present due to the thickness of the wing 2, and since the wing tip 5 is smoothly continuous with the cone-like hub 8, the wing 2, the cone-like hub 8, and To enter the space between the pump casings 4 without any obstruction. In this way, liquids containing solids etc.
It is fed without clogging the gap between the outer periphery and the pump casing 4. That is, the single-blade impeller pump of the present invention and the conventional example operate in the same manner. It has been found that since the blades 5a on the inlet side have a constant thickness, solids etc. can enter between the blades more smoothly than in the conventional example.

Due to the shape of the impeller 1, the suction section has blades 2a, etc. standing up against the pump main shaft, so it performs an axial flow action, and on the wake side, the blades 2e, etc. lie against the pump main shaft, so it performs a centrifugal action. . Therefore, the eighth conventional example
As shown in the figure, the angle of attachment of the blade impeller to the conical hub 8 is almost the same from the suction side to the wake side, unlike the conventional impeller that has the same outer diameter, unlike the one that mainly acts on axial flow. Compared to the impeller 1 of the present invention, a higher head can be expected and the efficiency will also increase. This is also clear from the experimental results described below.

This efficiency increase can be considered as follows.

The impeller 1 of the present invention performs an axial flow action at the suction part and a centrifugal action at the downstream side,
In general, the following characteristics can be said about impellers:

1) The displacement-head curve of an axial flow pump has a steep slope.

2) In axial flow pumps, compared to centrifugal pumps, the shaft power on the cutoff point side is large and tends to level off or decrease as the discharge rate increases.

3) For axial flow pumps, the pump efficiency curve is less rounded than for centrifugal pumps. In other words, the range of high efficiency relative to the discharge amount becomes narrower.

The above trends are well known, and to illustrate, the first
It will look like Figure 0. Figure 10 shows the discharge amount on the horizontal axis and the total head and efficiency on the vertical axis.The solid line is for the centrifugal pump, and the dotted line is for the axial flow pump, and the requirements for both pumps are as follows. This is the case where they are the same. The pump of the present invention has characteristics that combine both axial flow and centrifugal flow characteristics. Furthermore, in the present invention, the amount of leakage from the gap between the tip of the blade closer to the discharge side and the pump casing 4 to the upstream side than to the wake side is larger in the conventional example, but it is considered to be less in the present invention. This is because in the conventional example, although a larger centrifugal force is applied to the liquid on the working surface of the blade 2, the center line 3 of the pump main shaft of the blade 2
Since the mounting angle α is constant, the amount of leakage from the gap between the tip of the blade 2 and the pump casing 4 increases from the downstream side to the upstream side as it goes toward the outlet side. This is because the mounting angle formed with the center line 3 of the main shaft is small, so the force that urges the liquid on the blade surface toward the blade tip side is not generated or can be made smaller compared to the conventional example. It is believed that for these reasons, the single-blade impeller pump of the present invention was able to achieve higher efficiency than the conventional example. In addition, the reason why the maximum efficiency value is higher than that of the conventional example according to the experimental results is considered to be that of the above two reasons, the reason explained later is more effective.

FIG. 9 is a diagram showing a comparison of pump performance between the single-blade impeller pump of the present invention and the conventional pump described above. The horizontal axis shows the discharge amount, and the vertical axis shows the total head and efficiency.The solid line shows the single-blade impeller pump of the present invention, and the dotted line shows the conventional example. As is clear from the figure, the single-blade impeller pump of the present invention is improved in terms of maximum efficiency over the conventional example, and the pump head of the single-blade impeller pump of the present invention in this respect is
H ₁ and the conventional example as H ₂ , H ₁ /H ₂ = 1.2~
It was 1.5.

As described above, since the single-blade impeller pump of the present invention is more efficient than the conventional example and has a larger head, conversely, if the pump has the same head, the pump can be made smaller.

As described above, the present invention provides a pump in which an impeller having threaded blades with a conical outer circumference is housed in a conical pump casing, in which the installation angle of the blades to the hub is changed from the inlet side to the outlet side. Since the pump is gradually made smaller, the pump efficiency increases, and the head for the same discharge amount increases, and if the pump capacity is kept the same, the pump can be made smaller.

By improving the pump efficiency as described above, the single-blade impeller pump can be made smaller and lighter.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of an embodiment of the present invention, Fig. 2 is a partially enlarged front view of Fig. 1, Fig. 3 is an explanatory diagram of the operation of Fig. 1, and Fig. 4 is an illustration of the operation of the conventional example. A vertical sectional view to be explained, FIG. 5 is a partially enlarged front view of FIG. 4, and FIG.
7 and 7 are drawings showing the airfoil of the present invention,
Figure 6 is a front view, Figure 7 is a longitudinal sectional view, Figure 8 is a longitudinal sectional view of a conventional airfoil, Figure 9 is a comparison diagram of pump performance, and Figure 10 is a centrifugal pump and an axial flow pump. It is a performance comparison diagram. 1... Impeller, 2... Blade, 3... Center line, 3'... Pump main shaft, 4... Pump casing, 5... Blade tip, 6...
Suction port, 7...Discharge casing, 8...Conical hub,
9... Boundary line, 10... Radiation, 11... Outer circumference, 12...
Intersection, 2a to 2e...wings, α...mounting angle.

Claims (1)

[Claims] 1. On a pump casing that has a conical rotating surface between the suction port and the discharge casing, a conical hub is formed with a conical screw blade whose outer circumferential rotating surface approaches the conical rotating surface of the pump casing with little clearance. In a single-blade impeller pump in which a rotatably supported impeller is rotatably supported within a casing, the angle at which the blades are attached to the hub of the impeller is 30 to 60 degrees on the inlet side and 0 to 40 degrees on the outlet side, respectively. A single-blade impeller pump that is tilted more toward the suction port, and the angle of the blade with the pump main axis becomes smaller gradually from the inlet side to the outlet side.