Reinforced vane

Abstract: An aerofoil (10) for a turbocharger stator for a large diesel engine has a convex, upper wall (12) and a concave, lower wall (14) with a leading edge (16) and a trailing edge (18). A wiggle strip (22) extends the length of the aerofoil and is brazed to the walls to provide added strength. The inner surface of the wall (12) is reinforced by a plate (20) extending from the trailing edge to a point in the region of the maximum spacing between the walls (12, 14). The plate is a shaped reinforcement piece and gives added strength to the area of the wall (12) which is impacted by cleaning medium. It provides a localised reinforcement to the area which is prone to damage by cleaning.

Description: The present invention relates to a vane for a turbocharger stator as used on large diesel engines, two-stroke and four-stroke. Such large diesel engines in many instances use heavy fuel which gives rise to extremely dirty exhaust gases. This results in an accumulation of solid carboniferous material on the vanes of the engines, resulting in a loss of efficiency. Regular cleaning is therefore necessary in order to maintain the performance of the turbocharger and this is normally effected by introducing a hard medium into the exhaust gas upstream of the turbocharger. The impact of the medium on the internal surfaces of the turbine dislodges the impurities. However, a disadvantage of this cleaning process is that because the exhaust gases are moving at a relatively high speed, the impact of the medium on the vanes can deform the suction surface of the vanes. DE-C-892 698 discloses a vane for a turbocharger stator, the vane being of generally hollow construction with a convex wall and a concave wall meeting at a leading edge and a trailing edge of the vane. The convex wall is thickened over a portion of its length extending from the trailing edge. The present invention seeks to provide an improved vane for a turbine impeller. Accordingly, the present invention provides a turbocharger stator vane, wherein: the vane is of hollow construction with a convex wall and a concave wall meeting at a leading edge and a trailing edge of the vane; and said convex wall is thickened over a portion of its inner surface; characterised in that said convex wall is thickened over said portion of said inner surface by a reinforcing plate secured to said inner surface of said convex wall; and in that said plate extends from said trailing edge to a point in the region of the maximum spacing between said convex and concave walls to serve as a reinforcement to an area of the vane prone to damage during cleaning by impacting cleaning materials. A preferred form of vane according to the present invention has internal reinforcements in the form of sheet material pleated in a direction substantially parallel to the trailing and leading edges. A vane according to the present invention enables the use of relatively thin material for the vane walls with localised reinforcement to the area prone to damage by cleaning. The present invention is further described hereinafter, by way of example, with reference to the accompany drawing which illustrates a preferred embodiment of vane according to the present invention. Referring to the drawing, this is a cross-section through a vane 10 in the form of an aerofoil for a turbocharger stator for a large diesel engine. The aerofoil has a convex (upper) wall 12 and a concave (lower) wall 14, a leading edge 16 and a trailing edge 18. The aerofoil is manufactured from a thickness of material dictated by the radius of its trailing edge. A typical example of such an aerofoil would have chordal length of 100mm, a thickness of 12mm to 14mm and a trailing edge 18 radius of 0.5mm. A wiggle strip 22 extends the whole length of the aerofoil and is brazed into position to give added strength. The inner surface of the convex wall 12 has a reinforcing plate 20 secured to it, typically by brazing, the reinforcing plate 20 extending from the trailing edge 18 to a point in the region of maximum spacing between the convex and concave walls 12,14. The plate 20 is a shaped reinforcement piece and is designed to give added strength to the area impacted by cleaning medium. It extends into and fills the volume formed by the curvature of the trailing edge 18. The invention, therefore, relates to the use of thin material for aerofoils with localised reinforcement to the area prone to damage by cleaning.

Claims: A turbocharger stator vane (10), wherein the vane is of hollow construction with a convex wall (12) and a concave wall (14) meeting at a leading edge (16) and a trailing edge (18) of the vane; and said convex wall (12) is thickened over a portion of its inner surface; characterised in that said convex wall is thickened over said portion of said inner surface by a reinforcing plate (20) secured to said inner surface of said convex wall (12); and in that said plate extends from said trailing edge (18) to a point in the region of the maximum spacing between said convex and concave walls (12,14) to serve as a reinforcement to an area of the vane prone to damage during cleaning by impacting cleaning materials. A vane as claimed in claim 1 having internal reinforcement (20, 22). A vane as claimed in claim 2 wherein said internal reinforcement (22) is formed by sheet material pleated in a direction substantially parallel to the trailing and leading edges (18, 16). A vane as claimed in any of the preceding claims wherein said trailing edge (18) has a radius of substantially 0.5mm. A vane as claimed in any of claims 1 to 4 wherein said reinforcing plate (20) is secured by brazing. A vane as claimed in any of claims 1 to 5 wherein said reinforcing plate (20) is shaped so as to extend into and fill the volume formed by the curvature of said trailing edge (18). A vane as claimed in any of the preceding claims being in the form of an aerofoil.

Inventors: JONES RALPH GODFREY, JONES, RALPH GODFREY
Applicants: PRECI SPARK LTD, PRECI-SPARK LIMITED
Application year: 1993
Main classification: F01D5
IPC codes: F01D9, F02B3, F01D5