JPS5949435B2 - propeller pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a so-called propeller pump, which contains a pipe formed as a pump housing and a rotating impeller supported in the housing.

This type of pump is called an axial flow pump because it is designed so that the water to be pumped flows mainly in the axial direction of the impeller.

On the other hand, in a typical centrifugal pump, or radial flow pump, the body to be pumped flows in a direction perpendicular to the impeller.

Centrifugal pumps are very common in many fields and have been used frequently for pumping wastewater.

The disadvantage of this pump is that, due to its construction, the flow area is always limited, which impedes the flow of relatively large obstructions.

Additionally, non-rigid elongated obstacles such as threads, ropes, and strings, such as hospital waste, or farm waste, such as straw, hay, etc., can wrap around the propeller and stop the pump.

Another disadvantage of radial flow pumps when compared to axial flow pumps is their complex construction and high material usage per unit.

Accordingly, the use of axial flow pumps for pumping wastewater has long been an issue.

This may be particularly desirable for large flow rates, as material savings become even more important with larger pump units.

Savings in materials will reduce both its weight and cost.

To date, axial flow pumps for pumping wastewater have not been successfully tested because their efficiency is too low.

To obtain acceptable efficiency, the pump housing must be equipped with a differential user after the impeller that converts the kinetic energy of the pumped body into pressure energy.

It was determined that the differential user, consisting primarily of multiple vanes fixed to the central bubble, was the cause of the pump stoppage.

According to the present invention, that problem is solved by providing a pump housing with a plurality of radial differential user vanes on its pressure side extending inwardly from the mantle surface of the pump housing, the structure of which includes a free center flow path. However, the differential user blade has a shorter radial length in the pump impeller direction.

In the drawing, 1 is a cylindrical pump housing with a pump impeller 2, 3 is a drive shaft, 4 is a vane of the impeller, 5 is an elongated charging collar that shields the shaft 3 and extends from the top of the impeller 2, and 6 is the converging bottom of the extension bubble.

7 indicates the gap between the impeller and the pump housing, 8 indicates the vanes of the differential user, and 9 indicates the discharge center space.

The pumped body flows in the direction of the arrow.

In order to prevent the elongated fibrous material from wrapping around the drive shaft 3, the pump impeller is made long and a relatively large diameter charging collar 6 is provided.

This structure prevents the fibrous material from wrapping. Since the impeller blades 4 are fixed to a relatively large hub and have a maximum diameter slightly smaller than the inner diameter of the pump housing, there is a gap between the impeller blades and the pump housing wall.

This gap of up to about 10% of the pump housing inner diameter ensures that the elongated fibrous material does not stick between the outer part of the vane and the pump housing wall.

Furthermore, the leading edge of the vane has an acute receding angle, which causes the elongated fibers to migrate outward around the vane.

The pump impeller has a bub 6 with a smooth surfaced bottom extending downwards and converging towards the centre, this is necessary to reduce the pressure drop after the impeller.

The bottom part 6 of the bubble is shaped like a truncated cone or a hemisphere.

It is important to have a smooth surface so that obstacles floating in the wastewater and transported by the wastewater can slide onto the surface without sticking to it.

In theory, it is possible to replace the extension bub with one that almost touches the pump housing.

However, in practice it is difficult to contact the pump housing without risking the contact mechanism causing the pump to stop.

Additionally, the differential user section is formed to minimize the risk of pump stoppage.

By attaching the vanes to the inner surface of the pump housing, the common differential user bubble is eliminated and a free center flow path 9 is provided.

Furthermore, the leading edges of the vanes facing in the flow direction diverge toward the inner surface of the housing with a swept angle, thus directing the elongated fibers toward the center and the free flow path 9.

The risk of pump stoppage due to these fibers is therefore eliminated.

By combining the processes in accordance with the present invention, a device is obtained which combines the best properties of conventional centrifugal and axial flow pumps with respect to efficiency and ability to transport media containing large solid obstructions as well as elongated fibrous materials.

The pump is primarily for pumping sewage, but applications in other fields are also possible.

Although the principles of the invention have been described with respect to particular devices and applications, it should be understood that this is for the purpose of illustrating the embodiments and is not intended to limit the scope of the invention.

[Brief explanation of the drawing]

The drawing is a partial sectional view of a propeller pump according to the invention. 1...Pump housing, 2...Pump impeller, 3...Drive shaft, 4...
- Impeller blade, 5...Brim, 6...Hub, 8...Differential user blade.

Claims (1)

[Scope of Claims] 1. A tubular housing with a lateral part for water intake and a central opening for water discharge, a shaft extending from an outer drive motor into the housing and surrounded by a protective tube, and fixed to the shaft. a rotating impeller disposed centrally within the housing, drive vanes extending radially from the housing center bub to the housing inner surface and regularly distributed circumferentially; In an impeller pump for pumping wastewater containing relatively bulky obstructions and elongated flexible fibers having a set of rearwardly arranged radial differential vanes, the pump comprises: (a) said water suction lateral; (b) said central water discharge opening is located in the lower part of the housing and extends over the entire diameter of the housing; the housing is provided with flanges at its suction and discharge ends which can be fixed to conduction pipes and waste water sources; (c) said shaft 3 penetrates from the top of the housing 1 in the direction of its longitudinal axis and extends from said water suction lateral part; (a) a protective tube 5 extending across the entire diameter and disposed in the housing part at an axial distance from the lateral suction opening; (a) the impeller extends diametrically from the protective tube; consisting of a central bub which increases the velocity and ends in a radially converging bottom with a smooth surface, e.g. a hemisphere or a truncated cone, on its lower surface, from the sides of which said drive vanes 4 contain floating obstacles. The vanes 4 extend in the radial direction of the inner surface of the housing at a distance leaving a free gap for the passage of waste water, for example 1% to 10% of the inner diameter of the housing, and these vanes 4 are at an acute angle from the longitudinal axis of the pump in the direction of rotation of the impeller. (e) the differential user vanes 8 extend radially from the wall of the tubular housing 1 in the direction of the longitudinal axis of the impeller pump; , the edges of the vanes are spaced far enough away from the longitudinal axis to leave an axial center gap 9, and the edges of the vanes on the side facing the bottom of the impeller are inclined at an obtuse angle towards the inner surface of the housing, whereby the vanes 8 characterized in that an intermediate gap is provided between the impeller and the impeller, subsequent to the gap around the blades 4, of sufficient width to allow the passage of wastewater containing said obstruction over the entire length of the housing; The protective pipe 5 and the impeller 2 prevent long and thin flexible fibers floating in the wastewater sent from winding around the shaft and sticking to the blade edges, and removing all obstacles in the wastewater.
, on its vanes 4 and its smooth bottom 6 and through the gap between the housing, impeller and differential vanes 8 towards the central discharge of the pump.