FI73796C - Eccentric pair at the impeller in a pump. - Google Patents

Description

73796

PUMP IMPROPER PASSION CENTER - EXCENTERPAR VID LÖPHJULET I EN PUMP

The present invention relates to a clean pole of a narrow gap between a pump, in particular a drain pump and a body facing it in the direction of its axis of rotation, such as a narrow housing.

When pumping solids containing solids, such as sewage, the centrifugal pump tends to fail quickly, or at least the power requirement increases sharply as the solids wedge into the gaps between the impeller and the pump housing. In addition, fibrous solids, when wedged behind the impeller, cause interference in the shaft seal.

Attempts have been made to solve this problem in many different ways. One known solution is to provide the end surfaces of the impeller with auxiliary blades, which are generally radial. In this case, the corresponding surface of the pump housing is either smooth or helically grooved. The function of the grooves is to "push" the solid outwards. Another solution is to provide both surfaces with a spiral groove. In addition, Finnish patent 49345 discloses a solution in which the gap between the pump housing and the impeller is grooved so that contaminants escape through the grooves. The grooves are also equipped with tear members that grind the solids trapped in the gap. Another known solution is to immerse the impeller plate in the housing, in order to prevent solids from getting between the impeller plates and the housing.

DE-A-832549 discloses a solution in which the projections are only partially aligned on the circumference. Impurities can easily pass between these points, where the gap is considerably larger than at said points. This is detrimental above the impeller, as permeable contaminants accumulate there and interfere with the operation of the shaft seal.

73796 2 Thus, despite these numerous attempts, the problems associated with centrifugal pumps have not been eliminated.

It is an object of the present invention to provide a mechanism by which the gap between the impeller and the pump housing remains clean. The invention is characterized in that on the side of the impeller there is an axially eccentric projection fixedly connected to the impeller, against which a protrusion also fixedly connected to the pump housing is arranged so that the maximum distance of the impeller projection from the center line is greater than the smallest distance of the pump housing the minimum distance of the protrusion from the centerline of the shaft is less than the maximum distance of the protrusion of the pump housing from the centerline of the shaft, and that the radius of the sealing path bounded between the protrusions is less than the minimum distance of the impeller projection from the centerline of the shaft. This has been found to keep the gap between the pump housing and the impeller clean, making the pump more reliable and not requiring continuous removal of the impeller for cleaning. In addition, the eccentric in the impeller can be made to act as a counterweight to the wing imbalance in the single-impeller impeller. This saves on other cumbersome balancing measures.

In the following, the invention will be explained in detail with reference to the accompanying drawings, in which

Fig. 1 shows an eccentric pair according to the invention between an impeller and a pump housing,

Fig. 2 shows a section of Figs. 1 along lines II-II, and

Fig. 3 shows a preferred embodiment of the invention.

Figure 1 shows an impeller 1 which is rotatable by means of a shaft 2. The impeller is mounted by means of a shaft 73796 3 against the pump housing 3 so that a narrow gap 7 is left between them. It is essential in the invention that both the pump housing 3 and the impeller 1 are provided with eccentric projections 5, 6 whereby the area transverse to the axis 2 of the gap 7 between the projections 5, 6 alternately increases, decreases alternately. At its maximum, this area is when the eccentrics 5, 6 completely overlap and at its smallest when the impeller rotates 180 ° from this position, which is shown in Fig. 2. Thus, the gap is allowed to open from time to time, whereby the solid enters. Reference numeral 4 denotes the sealing space of the pump housing 3 in which the shaft seal is installed.

The structure of the impeller according to the invention can best be described in such a way that the maximum distance of the impeller projection from the shaft centerline is greater than the minimum distance of the pump housing projection from the shaft centerline. is less than the minimum distance of the impeller projection from the centreline of the shaft.

Figure 3 shows a preferred embodiment of the invention in which both sides of the impeller 1 are provided with an eccentric pair. The water to be pumped enters the impeller in the direction of Fig. 3 from below through a wide slot 8. The slot itself naturally extends over the slot 9 centrally with respect to the axis of rotation of the impeller wheel.

It will be clear to a person skilled in the art that the invention is not limited to the above-mentioned exemplary embodiments, but can be modified within the scope of the appended claim.

Claims (1)

CLAIM 73796 A mechanism for cleaning a narrow gap (7) between a pump, in particular a drain (1) in the direction of the impeller (1) of a sewer pump and its axis of rotation (2), such as , a protrusion (5) eccentric to the shaft (2), against which a protrusion (6) also fixedly connected to the pump housing (3) is arranged so that the maximum distance (A) of the protrusion (5) of the impeller (1) from the center line of the shaft (2) is greater than the smallest distance (C) of the projection (6) of the pump housing (3) from the center line of the shaft (2) maximum distance (D) from the center line of the shaft (2), and that the radius (R) of the seal space (4) bounded between the projections (5, 6) is smaller than the minimum distance (B) of the projection (5) of the impeller (3) from the center line of the shaft (2) . li: