EP2383471A1

EP2383471A1 - Slurry pump

Info

Publication number: EP2383471A1
Application number: EP10161379A
Authority: EP
Inventors: Aart Van den Dool
Original assignee: Castart BV
Current assignee: Castart BV
Priority date: 2010-04-28
Filing date: 2010-04-28
Publication date: 2011-11-02

Abstract

The invention relates to a slurry pump (1) comprising:
- a housing having an inlet (2) and an outlet (3);
- an annular rotor (6) with a central axis (8), the rotor being rotatably arranged in the housing;
- a number of impeller vanes (7) arranged on the annular rotor and directed inwardly, wherein the path (15) of the tips (12) of the impeller vanes define the outer edge of a through flow area; and
- driving means (9) to drive the annular rotor;
barrier means (11) which are arranged in the inlet (2) and cover in view of the flow direction, during use of the pump, at least a bottom part of the rotor (6).

Description

The invention relates to a slurry pump comprising:

a housing having an inlet and an outlet;
an annular rotor with a central axis, the rotor being rotatably arranged in the housing;
a number of impeller vanes arranged on the annular rotor and directed inwardly, wherein the path of the tips of the impeller vanes define the outer edge of a through flow area; and
driving means to drive the annular rotor.

Pumping slurry while dredging is commonly done with centrifugal pumps. A centrifugal pump has typically an axial inlet and a tangential outlet. The necessary piping to connect such a centrifugal pump have necessarily a number of bends, especially when two or more pumps are arranged in series.
Slurry is a very abrasive fluid containing sand and rocks. This results in a high wear of the pumping system, in particular at bends and in the pump. Therefore it is common to use parts, which can be replaced easily. For a centrifugal pump, the pump shell, the impeller, wear plates and suction liner can be replaced relatively easily.
However, each maintenance to the pumping system is time and cost consuming. Especially when new parts have to be installed.
Another type of pump, mentioned in the preamble, is an inline pump, which can be arranged in line with a pipeline, such that the slurry does not need to go through bends and only has to flow in a linear direction. The impeller vanes extend into the pathway and impel the slurry in a linear way, contrary to a centrifugal pump in which the slurry is sucked in axially, impelled radially and expelled tangentially.
In a pipeline however, the heavy parts, like rocks tend to sink to the bottom of the slurry flow. If these rocks reach the pump they will hit the impeller vanes and cause substantial wear.
It is accordingly an object of the invention to provide a slurry pump according to the preamble, in which the disadvantages are reduced.
This object is achieved with a slurry pump according to the preamble, which is characterized by barrier means which are arranged in the inlet and cover in view of the flow direction, during use of the pump, at least a bottom part of the rotor.
The barrier means thus shield of the lower part of the rotor, such that the heavy parts in the slurry cannot get into contact with the impeller vanes.
In a preferred embodiment of the slurry pump according to the invention the barrier means extend to the outer edge of the through flow area. This ensures that the full vanes at the bottom are shielded from the heavy parts in the slurry.
The barrier means provide a kind of speed bump in the slurry pump, such that the heavy parts jump over the bottom impeller vanes.
Preferably the barrier means extend over at least 15% of the arc of the annular rotor. This ensures that the major part of the rocks in the slurry will be shielded from the impeller vanes.
In another preferred embodiment of the slurry pump according to the invention, the driving means comprise a number of coils arranged around the circumference of the annular rotor, such that the coils interact with the rotor and drive the rotor. As a result a linear drive motor is provided for driving the rotor and the arranged impeller blades.
In yet another embodiment of the slurry pump according to the invention, the peripheral surface of the annular rotor is provided with gear teeth and wherein the driving means engage on the gear teeth to rotate the annular rotor. With the teeth on the peripheral surface it is possible to drive the rotor with a more conventional motor like an electric motor. The output shaft of such an electric motor can be provided with a gear which engages on the peripheral surface of the annular rotor.
Preferably the inlet, outlet and through flow area are arranged substantially in line with each other. This provides for an effective inline pump.
In another preferred embodiment of the slurry pump according to the invention the inlet and outlet are arranged in line with each other and wherein the barrier means are provided by arranging the annular rotor eccentric from the inlet and outlet. Due to the eccentric arrangement of the rotor, part of the rotor is outside of the flow path, such that the barrier means are provided by the inlet part and outlet part of the pump.
The slurry pump according to the invention can be arranged inline in a pipe line. Accordingly less elbows are needed in the pumping room in comparison to prior art centrifugal pumps, especially when two or more pumps are arranged after each other.
Furthermore an inline pump has the advantage of creating less disturbance in the water due to its much more streamlined design without elbows, when used on a hopper dredger.
With an inline pump wear parts are lighter and easier to produce or cast, as the parts are less complex than prior art centrifugal pumps.
These and other features of the invention are elucidated in conjunction with the accompanying drawings.

Figure 1 shows a first cross sectional view of a first embodiment of a slurry pump according to the invention.
Figure 2 shows a second cross sectional view of the first embodiment.
Figure 3 shows a cross sectional view of a second embodiment of a slurry pump according to the invention.
Figure 4 shows a variant of the slurry pump according to figure 1.

Figure 1 shows a first embodiment of a slurry pump 1 according to the invention. The slurry pump has an inlet section 2 and an outlet section 3. The inlet section 2 has a flange 4 for connection to a supply pipe (not shown). The outlet section 3 has also a flange 5 for connection to further piping (not shown).
In the middle of the housing 2, 3 of the pump 1 an annular rotor 6 is arranged. This annular rotor 6 has a number of impeller vanes 7 directed to the center axis 8 of the rotor 1. Around the rotor 6 a number of coils 9 are arranged for driving the rotor 6. The coils 9 are arranged behind a removable cover 10, which enables a simple exchange of the coils 9 or the rotor 6. The rotor 6 is sealed from the housing by sealings 18. This prevents water or slurry to get in to contact with the coils 9.
The bottom 11 of the inlet section 2 is inclined such that the bottom 11 runs up to the level of the tip 12 of the impeller vane 7. Rocks 13 or heavy pieces in the fluid will sink to near the bottom 11. As the bottom 11 is inclined the heavy pieces and rocks 13 will be guided over the tip 12 and it will be prevented that they do contact the impeller vanes 7.
At the outlet section 3, the bottom 14 is also inclined to provide a smooth flow of the fluid and reduce any turbulence just after the impeller vanes 7.
Figure 2 shows a cross sectional view in flow direction. The tips 12 of the impeller vanes 7 describe a path 15, which defines the outer edge of a through flow area 16.
Clear from figure 2 is that the inclined bottom 11 of the inlet section 2 lifts the rocks and heavy particles to a level in which they are guided in the through flow area 16, preventing contact with the impeller vanes 7.
The bottom 11 of the inlet section 2 is defined such that along an arc of the annular rotor 6, defined by the angle α, the bottom 11 extends above the outer edge 16.
Figure 3 shows a cross sectional view of a second embodiment 20 of a slurry pump according to the invention. The pump 20 has a pipe shaped housing 21 with a center axis 22. In the middle of the housing 21 an annular rotor 23 is arranged. On the inside of the annular rotor 23 a number of impeller vanes 24 are arranged. On the peripheral surface of the annular rotor 23 a number of gear teeth 24 are arranged.
The center axis 25 of the annular rotor 23 is eccentric to the center axis 22 of the pipe shaped housing. As a result the tip 26 of the bottom impeller vane 26 is below the inner bottom wall of the housing 21, such that heavy particles in the pump fluid will not contact any of the impeller vanes 24.
Another advantage of the eccentric arrangement of the rotor 23, is that an electric motor 27 can be arranged near the housing 21 and that a gear 28 arranged on the axle 29 of the electric motor 27 can engage the gear teeth 24.
Figure 4 shows a variant of the slurry pump according to figure 1. The same reference signs are used for the same parts.
The slurry pump 30 is different from the slurry pump 1 of figure 1, in that the bottom part 14 of the outlet section 3 is flat. As a result the bottom part of the rotor 6 is exposed on the side of the outlet section 3. The advantage is that the impeller vanes 7 have a slightly increased contact surface with the fluid, such that the power is transferred better to the fluid. Also sand and other particles, which could have sunk to the bottom of the pump 30 between the rotor 6 and the housing are washed out more easily.

Claims

Slurry pump comprising:
- a housing having an inlet and an outlet;

- an annular rotor with a central axis, the rotor being rotatably arranged in the housing;

- a number of impeller vanes arranged on the annular rotor and directed inwardly, wherein the path of the tips of the impeller vanes define the outer edge of a through flow area; and

- driving means to drive the annular rotor;
characterized by barrier means which are arranged in the inlet and cover in view of the flow direction, during use of the pump, at least a bottom part of the rotor.
Slurry pump according to claim 1, wherein the barrier means extend to the outer edge of the through flow area.
Slurry pump according to claim 1 or 2, wherein the barrier means extend over at least 15% of the arc of the annular rotor.
Slurry pump according to any of the preceding claims, wherein the driving means comprise a number of coils arranged around the circumference of the annular rotor, such that the coils interact with the rotor and drive the rotor.
Slurry pump according to any of the preceding claims 1 - 3, wherein the peripheral surface of the annular rotor is provided with gear teeth and wherein the driving means engage on the gear teeth to rotate the annular rotor.
Slurry pump according to any of the preceding claims, wherein the inlet, outlet and through flow area are arranged substantially in line with each other.
Slurry pump according to any of the preceding claims, wherein the inlet and outlet are arranged in line with each other and wherein the barrier means are provided by arranging the annular rotor eccentric from the inlet and outlet.