FINGER PUMP

Abstract

In this pump, the angle between the imaginary tangent plane to the lip and passing through the axis and an imaginary straight line, perpendicular to the axis and passing through the point furthest from the axis of intersection of the upper surface of a finger with the lateral leading surface of this finger, is between 110 and 140.

Claims

1. A pump comprising a rotating impeller, a fixed volute surrounding the impeller and a finger fixed to the volute, wherein the finger is in the form of a pyramid with three lateral surfaces.

2. A pump according to claim 1, wherein a lateral surface of the pyramid is convex.

3. A pump according to claim 1, wherein the three lateral surfaces are curved.

4. A pump according to claim 2, wherein the three lateral surfaces are curved.

5. A pump comprising: an impeller rotating around a vertical axis and having at least one blade, a fixed volute having an inner wall and surrounding the impeller, a finger fixed to the volute just downstream of an input of a crossing groove machined in the inner wall of the volute, projecting below the blade in the direction of an axis and having an upper surface, at least a part of which is at a distance from the blade of 0.05 to 1 mm, wherein the upper surface of the finger is convex with a convex side facing the blade, a tangent to the upper surface has a furthest downstream point, a tangent to the blade has a point on the blade, depending on a position in rotation of the blade, vertically aligned over the furthest downstream, and the tangent to the upper surface forms an angle of 50 to 140, depending on a position in rotation of the blade, with the tangent to the blade on said point on the blade vertically aligned.

6. A pump according to claim 5, wherein there are two blades.

7. A pump comprising: an impeller rotating around a vertical axis and having at least one blade, a fixed volute surrounding the impeller and having a crossing groove, a finger fixed to the volute, projecting below the blade in the direction of an axis and having an upper surface and a lateral leading surface, wherein an acute angle between the upper surface and the lateral leading surface is between 90 and 60.

8. A pump according to claim 7, wherein an angle between the lateral leading surface and a vertical axis is between 0 and 15.

9. A pump according to claim 7, wherein an angle between the upper surface and a horizontal axis is between 0 and 15.

10. A pump according to claim 8, wherein an angle between the upper surface and a horizontal axis is between 0 and 15.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In the attached drawings, given only as examples:

[0026] FIG. 1 is a partial exploded perspective view with the pump according to the invention pulled out;

[0027] FIG. 2 is a view from the suction side of the pump from the bottom to the top with respect to FIG. 1;

[0028] FIG. 3 is a cross-sectional view of the pump seen from above;

[0029] FIG. 4 is a perspective view from below of the finger;

[0030] FIG. 5 is a perspective view from above of the finger;

[0031] FIG. 6 is a view from above of the finger and

[0032] FIG. 7 is a cross-sectional view on line A-A in FIG. 6.

DETAILED DESCRIPTION OF THE INVENTION

[0033] The pump shown in FIG. 1 comprises an impeller 1 on a vertical axis X, X having two blades 2. The impeller rotates in the direction of the arrow F driven by the output axis of a motor (not shown). The blades 2 are inclined to the axis X, X. The impeller 1 is surrounded by a volute 3. The liquid to be transported enters the volute 3 through a suction inlet at the bottom of the pump. A finger 4 is fixed to the volute 3. A groove 5 is machined in the volute 3 and runs from the space between the impeller 1 and the volute 3 to the interior of the volute 3. A discharge tube leaves the volute 3 from a lip 10.

[0034] The finger 4 has a convex upper surface 8, the major part of which is 0.3 mm from the blades 2 when the latter pass in front of the finger 4. The tangent 11 to the upper surface 8 at its point furthest downstream forms with it, depending on the position in rotation of the blades 2, an angle of 90 with the tangent 12 to the blade 2 at a point vertically aligned with the said point 7.

[0035] As shown in FIG. 3, the angle Y between the imaginary plane P tangent to the lip 10 passing through the axis X, X and an imaginary straight line D passing through the intersection of the upper surface 8 with the lateral leading surface 6 of the finger 4 and perpendicular to the axis X, X and at the furthest point from the axis X, X (point 13) is 130. The finger 4 is therefore at eight o'clock if the lip 10 is considered to be at midday.

[0036] The angle between the tangent to the downstream edge of the input of the groove 5 and the edge between the upper surface 8 and the lateral leading surface 6 is 170.

[0037] The finger 4 shown in FIG. 4 is in the form of a pyramid in which its upper surface 8, its lateral leading surface 6, and a lateral trailing surface 14, are all curved.

[0038] FIG. 7 shows that the angle 1 between the lateral leading face 6 of the finger 4 and a vertical axis Y-Y is between 0 and 15. It also shows that the angle 2 between the upper face 8 of the finger and a horizontal axis Z-Z, is between 0 and 15. Summing the two angles and subtracting from 90 gives the angle 3, which is an acute angle of between 90 and 60.