JPH04279795A - Pump - Google Patents

Abstract

PURPOSE: To provide an axial flow pump to remarkably reduce the clogging risk to a liquid containing fiber, refuse or the like. CONSTITUTION: A pump comprises an impeller hub 1 provided with vanes, motor units 2, 3, an annular channel 4, a pump housing 5, and vanes 6, a leading edge 7 and a bulb form 8 of the pump housing, and the vanes are designed to have strongly back swept leading edges in the direction of the flow to reduce the clogging risk of fiber, refuse or the like on the forward edge of the vanes, the fiber slides outwardly in the direction of a wall 5 of a housing in which the speed is maximized. In addition, the vanes are designed to increase the thickness of the bulb form toward the wall 6 and to reduce the thickness toward a trailing edge of the vanes. The fiber easily slides on the edge of the vanes, and the bulb form affects less to the flow as a whole.

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 rotating within a pump housing. Such pumps are broadly divided into centrifugal pumps and axial flow pumps.

0002

SUMMARY OF THE INVENTION A centrifugal pump includes a hub, at least one cover disk mounted on the hub, and several vanes.
It has an impeller consisting of e), a so-called open impeller. A closed impeller is provided with two cover discs and an intermediate blade. What these two types of pumps have in common is that the liquid is drawn into the center of the impeller in the axial direction and exits the impeller tangentially to its periphery.

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

[0004] When pumping sewage or some types of treated water containing elongated fibers, the pumping process may be carried out using rags,
Fibers and the like can get stuck in the forward edges of the blades on the impeller or in the pump housing. Such blockages initially induce vibrations in the pump, resulting in reduced efficiency, but eventually the pump becomes completely clogged. One way to get these unwanted objects out of the wing is to reverse the pump at intervals, but this is of course not an acceptable solution. Another way to reduce the risk of clogging is to equip the pump with a cutting device, which breaks up the contaminants before they are sucked into the impeller. An example of such a solution is Swedish Patent No. 82057.
No. 74-6. The disadvantage of this solution is that the cutting device wears out quickly, making the clogging problem even more troublesome.

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

The invention will be described in detail below with reference to the accompanying drawings, which show axial and longitudinal sections through an axial flow pump according to the invention.

[0007]

[Example] In the attached drawings, 1 is an impeller hub equipped with blades, 2 and 3 are motor units, 4 is an annular channel,
5 is the pump housing, 6 is the leading edge.
7 and 8 respectively.

The pump operates as follows. Rotating impeller blades 2 draw liquid through annular channel 4 . When the liquid passes through the vanes, it is coupled by the vanes 6 and obtains pressure energy.

In order to reduce the risk of fibers or the like clogging on the leading edge 7 of the airfoil 6, said airfoil is designed with a strong rear sweep in the direction of flow. The fibers are thus slid outward in the direction of the wall 5 of the housing pump where the speed is highest. In addition, the wing is shaped so that the bulbous part 8 increases in thickness towards the wall 6 and also at the trailing edge of the wing.
It is designed to reduce thickness towards the edges. In this way, the fibers slide easily over the edges of the airfoil, and the bulb as a whole has only a small influence on the flow. In order to prevent solid material from becoming stuck in the transition area between the leading edge 7 and the wall 5, said transition area is designed with a 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, etc.

[Brief explanation of the drawing]

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

FIG. 2 is a cross-sectional view along line A-A in FIG. 1;

[Explanation of symbols]

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

Claims (4)

[Claims] Claim 1: An axial flow type pump for pumping a liquid containing contaminants such as elongated fibers,
The pump is powered by a motor (1) driving a rotating impeller (1).
3), both of which are surrounded by a substantially pipe-shaped pump housing (5), which includes several pumps located downstream of said impeller (1). In a pump which supports said motor housing via a mounting device (6), said mounting device also serving as a vane for the liquid, the leading edge (7) of said vane (6) when viewed in the direction of flow. and have a backward sweep angle, i.e. their respective attachment to said pump housing (5) is located downstream of their respective attachment to said motor housing (3), and said Leading edge (
7) Pumps characterized in that their thickness is designed such that their thickness increases successively towards the bulbous part in the direction of said pump housing (5). 2. Pump according to claim 1, characterized in that the increased wall thickness of the vanes (6) is obtained by rounding their pressure and suction sides. 3. The rounding of the pressure side of the blade (6) ends abruptly at a certain distance from the attachment point in the pump housing (5). pump. 4. The transition between the leading edge (7) of the vane (6) and the pump housing wall (5) is formed with a radial radius, so that a smooth line is formed without forming sharp edges. A pump according to claim 1, characterized in that it has been obtained.