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: an impeller rotating around a vertical axis and having at least one blade, a fixed volute having a lip and surrounding the impeller, a finger fixed to the fixed volute just downstream of an input of a crossing groove machined in an inner wall of the fixed volute, projecting below the blade in the direction of the axis and having an upper surface, of which at least a part is at a distance from the blade of 0.05 to 1 mm, and a lateral leading surface, an angle between an imaginary plane tangent to the lip and passing through the axis and an imaginary straight line, perpendicular to the axis and passing through a point furthest from the axis of an intersection of the upper surface of the finger with the lateral leading surface, is between 110 and 140.

2. The pump according to claim 1, characterised in that the fixed volute is a spiral.

3. The pump according to claim 1, characterised in that an angle between the tangent to a downstream edge of the input of the crossing groove and an edge between the upper surface and the lateral leading surface is between 180 and 150.

4. The pump according to claim 1, characterised in that: the upper surface is convex with its convex side facing the blade, a tangent to the upper surface, at its furthest point downstream, forms, depending on a position in rotation of the blade, an angle of 50 to 140 with a tangent to the blade at the point vertically aligned with the said furthest point downstream.

5. The pump according to claim 1, characterised in that there is only a single groove and a single finger.

6. The pump according to claim 1, characterised in that a part of the finger that is at a distance of 0.1 to 1 mm from the blade, represents at least 50% of a surface area of the upper surface.

7. The pump according to claim 1, characterised in that the finger has the form of a pyramid with three lateral curved faces.

8. The pump according to claim 1, characterised in that an angle between an imaginary tangent plane to said lateral leading surface passing through a line of intersection of said lateral leading surface and said upper surface and an imaginary tangent plane of the upper surface passing the line of intersection of the lateral leading surface and said upper surface is between 60 and 90.

9. A pump comprising: an impeller rotating around a vertical axis and having at least one blade, a fixed volute surrounding the impeller, a finger fixed to the fixed volute just downstream of an input of a crossing groove machined in an inner wall of the fixed volute, projecting below the blade in a direction of the axis and having an upper surface, at least part of which is at a distance from the blade of 0.05 to 1 mm, and a lateral leading surface, characterised in that an angle between the tangent to the downstream edge of the input of the crossing groove machined in the inner wall of the fixed volute and an edge between the upper surface and the lateral leading surface is between 18 and 150.

10. The pump of claim 9 characterised in that the upper surface of the finger is convex with its convex side facing the blade and a tangent to the upper surface forms, at its furthest downstream point, depending on a position in rotation of the blade, an angle of 50 to 140 with a tangent to the blade at the point vertically aligned over said furthest downstream point.

11. The pump according to claim 10, characterised in that a part of the finger that is at a distance of 0.1 to 1 mm from the blade, represents at least 50% of a surface area of the upper surface.

12. The pump of claim 9, wherein an angle between an imaginary tangent plane to said lateral leading surface passing through a line of intersection of said lateral leading surface and said upper surface and an imaginary tangent plane to said upper surface passing the line of intersection of said lateral leading surface and said upper surface is between 60 and 90.

13. The pump according to claim 9, characterised in that the fixed volute is a spiral.

14. The pump according to claim 9, characterised in that there is only a single groove and a single finger.

Description

(1) In the attached drawings, given only as examples:

(2) FIG. 1 is a partial exploded perspective view with the pump according to the invention pulled out;

(3) FIG. 2 is a view from the suction side of the pump from the bottom to the top with respect to FIG. 1;

(4) FIG. 3 is a cross-sectional view of the pump seen from above;

(5) FIG. 4 is a perspective view from below of the finger;

(6) FIG. 5 is a perspective view from above of the finger;

(7) FIG. 6 is a view from above of the finger and

(8) FIG. 7 is a cross-sectional view on line A-A in FIG. 6.

(9) 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.

(10) 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.

(11) 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.

(12) 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.

(13) 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.

(14) FIG. 7 shows that the angle 1 between the lateral leading surface 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 surfae 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.