JPH0792072B2 - Pump with spiral blades - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a vertical shaft pump having a spiral blade, and in particular to a pump suitable for sewage treatment and the like.

BACKGROUND ART Conventionally, in vertical shaft pumps, a rotor having many blades extending radially in a plane perpendicular to the pump's main shaft is mounted at a lower position inside the pump casing and rotated to draw water up from the bottom end of the casing.

However, this vertical shaft pump has multiple blades that extend radially toward the casing in a plane perpendicular to the pump's main shaft, which narrows the area through which the water flows. This has the disadvantage that, particularly when pumping sewage, it can become clogged with cloth and solids that may be contained in the sewage.

Furthermore, a centrifugal pump disclosed in Japanese Patent Laid-Open Publication No. 57-181997 is known as a pump having one spiral blade.

However, such centrifugal pumps have the drawback that the water sucked in along the main axis of the pump flows in a direction perpendicular to the main axis, which can cause solid matter to become clogged inside the pump.

Also, depending on the water pumping environment, a vertical shaft non-blocking pump may be required.

SUMMARY OF THE INVENTION An object of the present invention is to provide a vertical shaft pump which is non-blocking and has a large head and discharge volume.

DISCLOSURE OF THE INVENTION In order to achieve the above object, the present invention provides a vertical shaft pump having one spiral vane fixed to the tip of the rotary drive shaft of the pump, at least one spiral vane fixed to the tip of the rotary drive shaft, the outer peripheral edge of the one spiral vane being close to the inner surface of a casing, and a plurality of twist guide vanes being arranged in a flow path within the casing above the spiral vane, wherein the casing has a bowl-like shape that bulges out in the direction of the rotary drive shaft,
A bell mouth is fixed to the lower end of the casing, and the tip of the spiral blade extends beyond the lower end of the casing into the inside of the bell mouth. The bowl-shaped portion of the casing surrounding the spiral blade and guide vane can be divided into a section between the spiral blade and the guide vane and a middle section of the guide vane, thereby resulting in a multi-stage configuration.

This configuration improves volumetric efficiency, increases head, and allows for a larger pump diameter, thereby increasing discharge volume. Generally, as the pump diameter increases, the impellers also become larger and their weight increases significantly. Therefore, a single spiral impeller tends to cause poor balance relative to the impeller drive shaft, generating harmful vibrations in the pump and reducing pump efficiency. However, the pump of the present invention, which uses multiple spiral impellers, achieves excellent balance and minimizes vibrations to the pump. This is because, with two spiral impellers, the suction and discharge ports in the casing are positioned axially symmetrically with respect to the pump shaft, resulting in excellent balance. Furthermore, with three spiral impellers, the suction and discharge ports are similarly distributed symmetrically, resulting in similar benefits.

In addition, a trumpet-shaped bell mouth, which forms the pump's suction port, is fixed to the bottom end of the casing, allowing it to draw water from a wider area. Furthermore, the tips of the spiral impellers extend beyond the bottom end of the casing into the inside of the bell mouth, further increasing the head and speed of the water drawn up near the suction port, thereby improving suction efficiency. Furthermore, the casing is a split type, and the parts between the spiral impellers and the guide vanes, as well as the middle part of the guide vanes, can be used as dividing lines to assemble the pump in multiple stages, making it easy to form the bowl-shaped part of the casing.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic cross-sectional view of a vertical shaft pump having one or more helical vanes according to the present invention.

FIG. 2 is a partial cross-sectional view showing the tip of the pump of FIG. 1, showing the case where one spiral blade is provided.

FIG. 3 is a partial cross-sectional view showing the tip of the pump of FIG. 1, showing the case where two spiral blades are provided.

FIG. 4 is a bottom view of FIG.

FIG. 5 is a bottom view of a pump of the present invention having three spiral blades.

BEST MODE FOR CARRYING OUT THE INVENTION The pump having a spiral vane of the present invention will be described in more detail below with reference to the drawings.

FIG. 1 is a schematic diagram of a pump 1 of the present invention, in which a hub 8 is fixed to the tip of a rotary drive shaft 2 that is rotated by a driving means, such as a motor (not shown), and at least one spiral blade 10 is attached to the hub 8.

When the drive shaft 2 is rotated, water is sucked from the suction port 4 of the bell mouth 24 provided at the bottom of the casing 20 of the pump 1. The sucked water flows through the spiral impeller inside the casing 20.
The water is straightened by a number of twisted guide vanes 14 provided at the top of the casing 10 and pumped up into the pipe 18 at the top of the casing 20. Each guide vane 14 is twisted by about 270 degrees to gradually straighten the water flow that is spirally pumped up along the spiral blades so that it flows straight in the pipe 18 and eliminates vibrations and other harmful effects on the pump.
4 is made long to obtain a moderate rectification effect.

As a result of lengthening the guide vanes 14, the casing 20 becomes longer. Therefore, it is necessary to shorten the length of the spiral vanes 10 for the assembly and maintenance of the pump.
and the guide vane 14 and at the intermediate portion of the guide vane 14, the guide vane 14 is divided into multi-stage portions 21, 22, and 23.

FIG. 2 is a partial cross-sectional side view showing the main part of the lower end of the pump of FIG. 1, showing the pump 1 having one spiral vane 10.

The spiral blade 10 is wound spirally at a suitable angle around the rotary drive shaft 2. The blade 10 is attached to the hub 8 at its base end 30, and the outer peripheral edge 32 on the opposite side of the base end 30 is attached to the casing 1.
The spiral impeller 10 is close to the inner surface of the hub 8. The hub 8 and spiral impeller 10 may be molded as a single unit by casting. The tip 33 of the spiral impeller 10 extends downward from the tip 9 of the hub 8, thereby forming a wide suction port 4. The gap between the upper and lower blade portions, which form the flow path, is made wide enough to allow cloth and solids contained in the pumped sewage to pass through.

When the drive shaft 2 is rotated, the pumped water is sucked in from the suction port 4, passes through the spaces between the blades, and flows to the discharge port 5, where it is straightened by the multiple long twisted guide vanes 14, as described above.

The spiral blade 10 is formed so as to improve the weight balance with respect to the drive shaft 2.
Unlike conventional pumps that have multiple vanes only on one surface, the vanes are present continuously over a predetermined length in the drive shaft direction, allowing for a large head.

In the figure, a vertical shaft mixed flow pump 1 has a bowl-shaped bulge in the portion of the casing 20 including the spiral blades 10 and the guide vanes 14.
However, it may be a vertical shaft axial flow pump in which there is no bowl-shaped portion and the casing 20 is entirely straight.

FIG. 3 is a partial cross-sectional side view showing the main part of the lower end of the pump 1 of FIG. 1, and FIG. 4 is a bottom view of FIG. 3.
A pump 1 is shown having two helical blades 10,11.

Each of the spiral blades 10, 11 is fabricated by processing a plate material into a spiral shape. As can be seen in Fig. 4, the blades 10, 11 are wound 360° spirally around the rotary drive shaft 2 of the pump 1, axially symmetrically and 180° out of phase with each other. The blades 10, 11 are attached to the hub 8 at their base ends 30, 30, respectively, and their outer peripheral edges 32, 32 on the opposite sides of the base ends 30, 30 are close to the inner surface of the casing 20.
The tip ends 33, 33 of each spiral blade 10, 11 extend downward from the tip end 9 of the hub 8, thereby forming wide suction ports 4, 4. The gap between the alternating blade portions of the two blades 10, 11 that form the flow path is made appropriately wide so that cloth and solids contained in the pumped sewage can pass through.

When the drive shaft 2 is rotated, the pumped water is simultaneously sucked in through the two suction ports 4, 4 positioned symmetrically along the axis, passes through the spaces between the blades, and flows in a single spiral direction to the two discharge ports 5, 5 positioned symmetrically along the axis, where the flow is straightened by the multiple long twisted guide vanes 14 as described above.

As explained above, the two spiral blades 10, 11
When a spiral impeller is provided, the impellers are axisymmetric, and the suction and discharge ports are also symmetric, resulting in a highly balanced pump. Furthermore, in the case of a single spiral impeller, considering one surface perpendicular to the drive shaft 2, energy is applied to the water at one eccentric point, preventing uniform application of energy, resulting in poor volumetric efficiency. While pump discharge is generally proportional to the pump diameter, a single spiral impeller cannot cover the entire volume of water. Therefore, increasing the pump diameter does not increase the discharge volume proportionally. On the other hand, in the case of a pump with two spiral impellers, energy is applied to the water at two axisymmetric points simultaneously on all surfaces perpendicular to the drive shaft 2, improving volumetric efficiency. This allows the pump diameter to be increased to increase the discharge volume and head. Tests of the vertical-shaft mixed-flow pump shown in Figure 3 revealed that its efficiency was 4-5% higher than that of a conventional mixed-flow pump.

Fig. 5 shows a pump in which three identical spiral blades 10, 11, 12 are attached to the hub 8, each of which is shifted in phase by 120°, instead of the two spiral blades of the pump in Fig. 3. In this case, too, the blades, suction ports, and discharge ports are evenly distributed, resulting in a well-balanced and
This results in a pump with good volumetric efficiency.

The number of spiral vanes to be provided is preferably determined depending on the size of the casing 20 of the pump 1, the conditions for making the flow of fluid in the pump uniform, and other design conditions.
The vertical shaft type mixed flow pump 1 is shown with a bowl-shaped bulge in the part including the casing.
The pump 20 may also be a vertical shaft axial flow pump having a straight overall shape.

Industrial Applicability As explained above, the pump with spiral blades of the present invention has a large head and can also increase the discharge volume, which has the advantage that the relay station for pumping that was previously installed when the head was small can be omitted, and the pump can be widely used in a variety of industries.

Furthermore, since the flow path within the pump is relatively wide and unidirectional in the direction of the drive shaft, it does not become clogged, and can be used to pump sewage and other water that may contain impurities.

Claims (4)

[Claims] [Claim 1] A pump in which at least one spiral blade (10) is fixed to the tip of a rotary drive shaft (2), the outer peripheral edge (32) of the spiral blade (10) is close to the inner surface of a casing (20), and a plurality of twist guide vanes (14) are arranged in a flow path within the casing above the spiral blade (10), wherein the casing (20) has a bowl-like shape that bulges outward in the direction of the rotary drive shaft (2), and the casing (20)
A bell mouth (24) is fixed to the lower end of the casing (20), and the tip of the spiral blade (10) extends beyond the lower end of the casing (20) to the inside of the bell mouth (24), and the spiral blade (10) and the guide blade (14) of the casing (20)
The bowl-shaped portion surrounding the spiral blade (10) can be divided into a portion between the spiral blade (10) and the guide vane (14) and an intermediate portion of the guide vane (14), and is composed of multi-stage portions (21, 22, 23). [Claim 2] A vertical shaft pump according to claim 1, wherein the spiral blades are made up of a plurality of blades (10, 11, 12) arranged at equal intervals and out of phase with each other around the rotary drive shaft. [Claim 3] A vertical shaft pump according to claim 2, characterized in that it has two spiral blades (10, 11) arranged axially symmetrically around the rotary drive shaft (2) with a phase difference of 180 degrees from each other. 4. A vertical shaft pump according to claim 2, wherein three rotors are arranged around the rotary drive shaft (2) with a phase difference of 120°.
A vertical shaft pump characterized by having spiral blades (10, 11, 12).