JPH0730751B2 - pump - Google Patents

Abstract

The invention concerns a non-clogging pump of centrifugal or axial flow type. The vanes (6) of the pump housing (5) are designed with strongly back swept leading edges (7) as seen in the direction of the flow, the vanes (6) being given a bulb form in the outward direction. <IMAGE>

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary pump having an impeller that rotates within a pump housing. Such pumps are roughly classified into centrifugal pumps and axial flow pumps.

[0002]

SUMMARY OF THE INVENTION Centrifugal pumps include a hub, at least one cover disc mounted on the hub, and a number of vanes.
It has an impeller consisting of e), a so-called open impeller. The closed impeller is provided with two cover discs and an intermediate blade. Common to these two types of pumps is that the liquid is sucked axially into the center of the impeller and exits the impeller in its peripheral tangential direction.

Axial pumps differ from centrifugal pumps in that the liquid exits the pump substantially axially. This fluid linking is accomplished by several vanes in the pump housing after the impeller. These wings also typically act as support elements within the housing structure.

When pumping sewage or certain treated water containing elongated fibers, the pumping work is rag,
Fibers and the like can become jammed and blocked in the forward edges of the blades on the impeller and in the pump housing. Such plugging initially induces vibrations in the pump, resulting in reduced efficiency, but eventually the pump is completely plugged. One way to get these undesired objects out of the wings is to reverse the pump at some interval, but this is not an acceptable solution, of course. Another way to reduce the risk of clogging is to equip the pump with a cutting device to break up the contaminants before they are drawn into the impeller. An example of such a solution is Swedish patent 82057.
No. 74-6. The drawback of this solution is that the cutting device quickly wears out, which makes the clogging problem even more troublesome.

The object of the invention is to solve the above-mentioned problem of clogging in a completely new and different way.
This solution is obtained by the device described in the claims.

The present invention will be described in detail below with reference to the accompanying drawings showing an axial cross section and a meridional cross section of an axial flow pump according to the present invention.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the attached drawings, 1 is an impeller hub having wings, 2, 3 is a motor unit, 4 is an annular channel, 5 is a pump housing, and 6 is a leading edge.
wing 7 and a sphere 8 are shown, respectively.

The pump operates as follows. The rotating impeller blades 2 suck the liquid through the annular channel 4. When the liquid passes through the blade, it is connected by the blade 6 to obtain pressure energy.

In order to reduce the risk of fibers or the like clogging on the leading edge 7 of the wing 6, said wing is designed to be strongly swept backwards in the direction of flow. The fibers are thus slid outwards in the direction of the housing pump wall 5 where the speed is highest. In addition, the wing is such that the bulb 8 increases the thickness towards the wall 6 and also the trailing edge of the wing.
edge) is designed to reduce the thickness. In this way, the fibers slide easily over the edges of the airfoil and the bulb has overall little effect on the flow. In order to prevent solid material from becoming trapped in the transition region between the leading edge 7 and the wall 5, said transition is designed with a radius radius and no sharp corners. There is.

The invention provides a device which significantly reduces the risk of clogging of pumps operating with liquids containing fibers, debris and the like.

[Brief description of drawings]

FIG. 1 is an axial sectional view of a pump according to an embodiment of the present invention.

2 is a cross-sectional view taken along the line AA of FIG.

[Explanation of symbols]

 1 Impeller hub 2,3 Motor unit 4 Annular channel 5 Pump housing 6 Blade 7 Leading edge 8 Spherical part

Claims (4)

[Claims] 1. An axial flow type pump for pumping a liquid containing contaminants such as elongated fibers, the pump comprising a motor (3) driving a rotary impeller (1). Both members are surrounded by a substantially pipe-shaped pump housing (5), which housing comprises several mounting devices (6) provided downstream of the impeller (1). In the pump, wherein the mounting device also serves as a vane for liquids, the vane (6)
The leading edge (7) of the blades has a receding angle rearward in the direction of flow, ie the attachment of each of these vanes to the pump housing (5) is to the respective motor housing (3) A pump located downstream of the mounting part, characterized in that the front edges (7) are designed such that their thickness gradually increases towards the bulb in the direction of the pump housing (5). . 2. Pump according to claim 1, characterized in that an increase in the wall thickness of the blades (6) is obtained by rounding their pressure and suction sides. 3. The pressurization-side rounding of the blade (6) ends abruptly after a certain distance from a mounting portion in the pump housing (5). Pump. 4. A radius rounding is formed at the transition between the leading edge (7) of the vane (6) and the pump housing wall (5) to provide a smooth line without sharp edges. The pump according to claim 1, which is obtained.