FI85749C - PUMP. - Google Patents

Description

85749

PUMP - PUMP

The present invention relates to a pump for transferring liquid medium 5 from the inlet side of the pump to the outlet side, the pump comprising an impeller or propeller having at least one vane and its shaft, the impeller having an inlet and an outlet edge, and the inlet side having a reduced flow cross-section the diameter is larger than the diameter of the outlet edge.

Pumping technology also requires pumps with a relatively low head (less than 5 m) compared to the volume flow. There are several such sites in both industry 15 and municipal water supply. Floodwater pumping also has low lift heights. Municipal water supply can be mentioned, for example, the pumping of return sludge at wastewater treatment plants.

20 At present, pumps with a smaller impeller inlet diameter than the impeller outlet diameter or propeller pumps with equal diameters are used for low head heights.

.25 The former are poorly suited for low lifting heights with low efficiency. Propeller pumps are better suited, but when the fluid contains consumables such as sand, the gap between the impeller blade and the mating surface wears larger, reducing efficiency and performance and because the diameter of the impeller inlet is equal to the diameter of the impeller outlet edge. Both solutions also have the disadvantage that, in order to improve efficiency, the inlet hopper is arranged before the 35 impellers or propellers, which causes the impeller to be positioned correspondingly higher (closer to the surface) in vertical pumps, thus increasing the risk of cavitation.

85749 2 The object of the present invention is to provide a pump for low head, which pump does not have the above-mentioned problems. The pump according to the invention is characterized in that the impeller is placed in the inlet hopper.

5

A preferred embodiment of the pump according to the invention is characterized in that the impeller has a fixed outer ring.

Another embodiment of the pump according to the invention is characterized in that a separate inlet pipe is connected to the pump before the inlet funnel, whereby the pump can also operate in a dry state.

Yet another embodiment of the invention is characterized in that the inlet funnel has a curved shape.

The pump according to the invention provides good flow efficiency (such as a propeller pump) and adjustability of the gap between the vane and the mating surface 20. Within the gap, it can then be reduced to larger by moving the hopper. Because the impeller (or propeller) is located in the hopper, it is lowered as much as possible, reducing the risk of cavitation. The solution is also inexpensive to manufacture, .25 because it is low. It is well suited for pumping gaseous liquids and sludges because, due to the large inlet diameter, the flow rate at the inlet is low, causing a slight pressure drop, preventing gas bubbles from growing and interfering with pump operation.

-30 3 85749

In the following, the invention will be explained in detail by means of preferred exemplary embodiments with reference to the accompanying drawings, in which Figure 1 shows a cross-section of a pump according to the prior art.

Figure 2 shows a cross-section of a pump according to an embodiment of the invention.

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Figure 3 shows a cross-section of a pump according to another embodiment of the invention.

Figure 4 shows a cross-section of a pump according to a third embodiment of the invention.

Figure 5 shows a cross-section of a pump according to a fourth embodiment of the invention.

Figure 1 shows a pump structure according to the prior art. It comprises an impeller 1 and its shaft 2. The impeller has one or more vanes 3. A gap S is left between the vane 3 and its mating surface. The impeller still has an inlet with a diameter and an outlet edge through which the dimension is D ^. In the prior art pump D2> shown in Figure 1. On the inlet side, the pump structure further comprises an inlet funnel 4, in which the flow cross-section decreases, and above which the impeller 1 is placed. The features and disadvantages of the structure were explained above.

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Figure 2 shows a pump according to the invention. In contrast to the prior art, the diameter of the inlet is larger than the diameter of the outlet edge, i.e.> Dj and the impeller 1 or propeller are located directly in the hopper 4. The gap S 35 between the vane 3 and its mating surface is adjustable in the structure according to the invention. in the vertical direction. As the gap becomes larger with use, it can be reduced by lowering the hopper. How such adjustment or transfer is carried out in practice will be obvious to a person skilled in the art and will therefore not be explained in more detail in this context.

Figure 3 shows a solution in which the impeller has a fixed outer ring 5. This further reduces the disadvantages caused by wear. In Fig. 4, an inlet-10 pipe 6 is connected to the pump, whereby the pump can also operate in a dry state. In Fig. 5, the inlet funnel 4 has a curved shape, which is more economically advantageous.

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 varied within the scope of the appended claims.

Claims (4)

A pump for transporting a fluid in medium from the inlet side of the pump to the discharge side, wherein the pump includes a impeller (1) with at least one blade (3) or a propeller with associated shaft (2), the impeller being provided with an inlet opening and an outlet edge, and where there is an inlet funnel (4) on the inlet side of the pump where the flow cross-section 10 decreases, and the inlet opening diameter (Dx) of the impeller (1) is larger than the outlet edge diameter (D2), in the inlet funnel (4). Pump according to claim 1, characterized in that the impeller 15 (1) has a fixed outer ring (5). Pump according to claim 1 or 2, characterized in that a separate inlet pipe (6) is connected to the pump before the inlet funnel (4), whereby the pump can function even in dry condition. Pump according to any of claims 1-3, characterized in that the inlet funnel (4) has a curved shape.