Hydrofoil impeller

Patent metadata

Field	Value
Publication number	US-2018280901-A1
Application number	US-201515523863-A
Country	US
Kind code	A1
Filing date	Nov 4, 2015
Priority date	Nov 6, 2014
Publication date	Oct 4, 2018
Grant date	—

Abstract

A hydrofoil impeller includes a central hub connected to a shaft, and being in the form of a flat plate and being perpendicular to the central axis. The central hub has first bolt holes arranged to form a pattern, the number of groups of first bolt holes corresponding to a number of blades attached to the central hub. At least three blades extend radially outwardly from the central hub, and have a group of second bolt holes arranged in a corresponding pattern to the first bolt holes so that the group of second bolt holes can be aligned with the group of first bolt holes and bolts can be placed through the first and second bolt holes to form bolted joints. The pattern in which the first holes and second holes are arranged in each of the respective groups of holes has a form of a closed curved shape.

First claim

1 . A hydrofoil impeller for producing fluid flow in an axial direction relative to a shaft rotating around its central axis in an agitated tank, said impeller comprising:
a central hub which is connected to the shaft, the central hub being in the form of a flat plate with a uniform thickness and being perpendicular to the central axis (x), the central hub having a number of groups of first bolt holes arranged to form a pattern, the number of groups of first bolt holes corresponding to a number of blades attached to the central hub, at least three blades extending radially outwardly from the central hub, each blade having a root portion, said root portion being in a form of a flat plate with a uniform thickness, said root portion having a group of second bolt holes arranged in a corresponding pattern in relation to the pattern of the first bolt holes so that the group of second bolt holes can be aligned with the group of first bolt holes and bolts can be placed through the first and second bolt holes to form bolted joints, wherein the number of holes in each group of first and second holes is at least five; and that the pattern in which the first holes and second holes are arranged in each of the respective groups of holes is in a form of a closed curved shape.

2 . The hydrofoil impeller according to claim 1 , wherein the central hub comprises an upper surface and a lower surface which is parallel to the upper surface; and that the root portion of each blade abuts against the lower surface of the central hub.

3 . The hydrofoil impeller according to claim 1 , wherein the number of the blades is three; the central hub is in the form of a triangle with rounded corners; the group of first bolt holes is disposed at each corner of the central hub; and the pattern in which the first holes and second holes are arranged in each of the respective groups of holes is in a form of an ellipse.

4 . The hydrofoil impeller according to claim 1 , wherein the number of the blades is five; the central hub is in the form of a circular disc; and the pattern in which the first holes and second holes are arranged in each of the respective groups of holes is in a form of a circle.

5 . The hydrofoil impeller according to claim 4 , wherein the impeller comprises five pieces of first spacer plates each of which has a pattern of bolt holes corresponding to the pattern of groups of first bolt holes and second bolt holes for each of the bolted joints, and which first spacer plates are arranged against and underneath the root portion of the blade to form spacing elements for the bolted joints.

6 . The hydrofoil impeller according to claim 5 , wherein the impeller comprises five pieces of second spacer plates each of which has a pattern of bolt holes corresponding to the pattern of the bolt holes of the first spacer plate, and which second spacer plates are arranged against the upper surface of the central hub to form spacing elements for the bolted joints.

7 . The hydrofoil impeller according to claim 1 , wherein each blade comprises a leading edge and a trailing edge in the direction of the rotation; and that the attachment of the blade at the root portion provided by the closed curve shaped pattern of bolted joints provided by said first and second bolt holes and bolts is located, in the direction of the rotation, in front of and near to the side of the leading edge of the blade and substantially behind the trailing edge of the preceding blade.

Assignees

• Outotec Finland Oy

Inventors

• Strömmer Ville
• Lehtonen Markus

Classifications

• F04D29/20

  Mounting rotors on shafts · CPC title

• F04D29/181 Primary

  Axial flow rotors (F04D29/185 take precedence) · CPC title

• F04D29/648

  especially adapted for liquid pumps · CPC title

• B01F7/00375

  Operations & Transport · mapped topic

• B01F7/22

  Operations & Transport · mapped topic