Rolls-royce Corporation

Rolls-royce and Associates Limited

Rolls-royce and Associated Ltd.

John O Fowler

James E Boardman

Colin I Adderley

Brian Richardson

Simon A Banks

Michael F Wignall

Arnold J Pratt

Alistair Calderwood

A submersible propulsor unit, comprising: a duct defined between a duct hub and a duct wall, the duct having a water inlet and a water outlet, a propeller means rotatably mounted within the duct, and an array of stator vanes extending between the duct hub and the duct wall, wherein the array of stator vanes comprises stator vanes having a first stiffness and stator vanes having a second stiffness.

Submersible propulsor unit

It is the norm to make diffusion bonded and superplastically formed heat exchanger panels from a trio of three sheet stacks, which employs four diffusion bonding stages and three superplastic forming stages. The concept described and claimed obviates one sheet from the central stack and provides only one passageway between the remaining two sheets. The advantages gained include less material and one bonding/superplastic forming stage is obviated with resulting savings in cost, time and machine utilization.

Heat exchanger manufacture

A plurality of hollow blades are produced by assembling a plurality of titanium sheets and a plurality of titanium blocks into a stack. At least one of the sheets is provided with a stop off material on one of its surfaces at a plurality of longitudinally spaced pre-selected areas to prevent diffusion bonding at these areas to define the hollow interiors of the blades. The edges and ends of the sheets are welded together and the blocks are welded to the sheets. The assembly is heated and externally pressurised to diffusion bond the sheets and blocks together. The integral structure so formed is then heated and internally pressurised to superplastically form at least one of the sheets at each of the pre-selected areas to produce a plurality of hollow blades. Thereafter the hollow blades are separated from each other by machining and simultaneously producing the aerofoil shapes.

Method of manufacturing hollow articles by superplastic forming and

A plurality of workpieces are assembled into a stack. Two of the workpieces are machined on one surface at predetermined positions from the edges of the workpieces. The workpieces are stacked so that the machined surfaces of the workpieces face away from each other. Two workpieces are provided with a stop off material on one of their surfaces to prevent diffusion bonding at predetermined positions. The edges of the workpieces are welded together and a pipe is welded to the stack to interconnect with the stop off material to form a sealed assembly. The workpieces are diffusion bonded together. The integral structure formed is heated and opposite ends of the integral structure are twisted relatively to contour the integral structure to a predetermined shape. The integral structure is heated and the machined portions on the workpieces are isothermally forged and then the twisted integral structure is internally pressurised to superplastically form one workpiece to produce an article, eg a fan blade.

Method of manufacturing an article by superplastic forming and diffusion

A plate-fin type of heat exchanger (400) facilitates exchange of heat between two process streams (S1, S2) e.g. high pressure methane and seawater. It comprises a matrix (M) of heat exchange plate elements (200') arranged side-by-side, flow passages (401) for the seawater process stream (S2) being defined between adjacent plate elements. The plate elements (200') are a high-integrity diffusion bonded sandwich construction comprising two outer sheets (101, 103--FIG. 3) and a superplastically expanded core sheet structure (102--FIG. 3) between the two outer sheets. The sandwich construction provides flow passages (117') for the methane process stream. Adjacent plate elements (200') are held in position relative to each other by serrated racks (403) which engage the edges of the plate elements.

Heat exchanger

It is common practice to assemble heat exchangers from a multitude of pre-formed and sometimes extremely delicate pieces. The pieces have to be held in jigs along with appropriately placed braze material and then heated to achieve brazing. The invention takes advantage of the ability which some materials have, to considerably extend their areas without rupturing, by using such materials in that they are assembled in the flat condition and then diffusion bonded, followed by inflation of the parts of the assembly which are to provide the fluid passageways, inlet manifolds and headers. The construction of heat exchangers is thus considerably simplified.

Heat exchangers and methods of manufacture thereof

A plurality of titanium sheets are assembled into a stack. At least one of the sheets is provided with a stop off material on one of its surfaces to prevent diffusion bonding at predetermined positions. The edges of the sheets are welded together and a pipe is welded to the stack to interconnect with the stop off material to form a sealed assembly. The assembly is heated and externally pressurized to diffusion bond the sheets together. The integral structure so formed is heated and opposite ends of the integral structure are twisted relatively to contour the integral structure to a predetermined shape. The integral structure is internally pressurized to break the adhesive bonds. The integral structure is heated and internally pressurized to superplastically form one sheet to produce an article, e.g. a fan blade.

A plate-fin type of heat exchanger (100) facilitates exchange of heat between two or more process streams (101, 102). It comprises a matrix (M) of two different types of heat exchange plate elements (P1, P2) inter-digitated with each other. Adjacent plate elements are metallurgically bonded together for good thermal contact by an activated diffusion bonding process. The plate elements (P1, P2) are high-integrity diffusion bonded sandwich constructions comprising two outer sheets (201, 203--FIG. 4) and a superplastically expanded core sheet structure (202) between the two outer sheets. The sandwich construction provides flow passages (P) for the process streams. Adjacent plate elements (P1, P2) carry different process streams (102, 102).

A plurality of workpieces are assembled into a stack. Two of the workpieces are machined on one surface at predetermined positions from the edges of the workpieces. The workpieces are stacked so that the machined surfaces of the workpieces face away from each other. Two workpieces are provided with a stop off material on one of their surfaces to prevent diffusion bonding at predetermined positions. The edges of the workpieces are welded together and a pipe is welded to the stack to interconnect with the stop off material to form a sealed assembly. The workpieces are diffusion bonded together. The integral structure formed is heated and opposite ends of the integral structure are twisted relatively to contour the integral structure to a predetermined shape. The integral structure is heated and the machined portions on the workpieces are isothermally forged and then the twisted integral structure is internally pressurized to superplastically form one workpiece to produce an article, e.g. a fan blade.

It is common practice to assemble heat exchangers from a multitude of pre-formed and sometimes extremely delicate pieces. The pieces have to be held in jigs along with appropriately placed braze material and then heated to achieve brazing. The invention takes advantage of the ability which some materials have to considerably extend their areas without rupturing by using such materials in that they are assembled in the flat condition and then diffusion bonded, followed by inflation of the parts of the assembly which are to provide the fluid passageways, inlet manifolds and headers. The construction of heat exchangers is thus considerably simplified.

Heat exchanger and methods of manufacture thereof

A compressed gas storage tank comprises a multi-layer sheet metal sandwich structure with a predetermined pattern of solid state diffusion bonds between all the neighburing layers. After the sheets have been solid state diffusion bonded together in the flat condition, the tank is blow formed between dies under superplastic forming conditions to produce at least one superplastically expanded core layer for containing the compressed gas. The configuration of the core layer is determined by the diffusion bond pattern. The expanded core layer provided internal bracing for the tank to give in rigidity and enable it to withstand the high internal pressures.

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Lancashire, United Kingdom

John O Fowler