Abstract:
A method is taught for the joining of a plurality of heat exchange tubes having a predetermined shape, such as a "Mae West" form, so as to obtain a tube bundle comprising a rocket engine thrust chamber. These tubes are joined to each other by laser powder injection welding, so as to close any gaps between adjacent tubes, and to securely bond the tubes together. A structural jacket is then affixed to the tube bundle, either in situ, by continuing to laser powder injection coat the surface, using an appropriate jacket composition, flame spraying or plasma spraying a suitable alloy in place, or by brazing or welding a previously formed jacket in place. In an extension of the invention, laser powder injection is performed to provide a repair method for the tube bundle, should the bundle be damaged or exhibit imperfect joining.
Abstract:
A gas turbine engine (10) includes a multi-stage combustion chamber (19) having a pilot stage (22) and a main stage (24), wherein during the low power setting only the pilot stage (22) is operating. During the non-operation of the main stage (24) a problem of coking occurs in a fuel supply system in general, and in a check valve (40) distributing fuel to the main stage, in particular. The check valve (40) is cooled by pilot fuel flowing through an auxiliary chamber (52) and is insulated by an air jacket (60) that is formed between the outer housing and the inner housing of the check valve.
Abstract:
The arcuate vane support segments (26) each carry a plurality of vanes (28) and have a pair of axially extending feet (38). These feet do not slide axially into a groove, but move radially against an arm (22) of the "T" shaped air seal. The casing ring (62) is translated axially in place entrapping the feet (38).
Abstract:
A frame of reference is selected, and control inputs provided by a vehicle operator are transformed to account for the orientation of a remotely operated vehicle with respect to the selected frame of reference such that the remotely operated vehicle responds to the control inputs with respect to the selected frame of reference. An earth frame of reference may be selected based on a fixed true heading, e.g., North, or based on the initial orientation of the vehicle operator. Alternatively, a vehicle frame of reference may be selected which provides a fixed frame of reference with respect to the vehicle and a variable frame of reference with respect to the vehicle operator. A vehicle operator frame of reference may also be selected based on the orientation of the vehicle operator with respect to earth, and control commands are transformed based on changes in both the operator orientation with respect to the earth reference and the remotely operated vehicle orientation with respect to the earth reference, which provides a fixed frame of reference with respect to the vehicle operator and a variable frame of reference with respect to the vehicle. The remotely operated vehicle heading transformation may be based on a selected forward, fixed or variable point on the vehicle related to a vehicle center of gravity, a forward part of the vehicle, the location of a sensor on the vehicle, or some other arbitrary reference location on the vehicle.
Abstract:
A gas turbine engine fan blade (34) having an airfoil portion (42) and a dovetail root portion (44) is enhanced by having spaced apart supporting ribs (65) extending into the dovetail root portion (44). The supporting ribs (65) define a plurality of hollow cavities (66) extending into the dovetail root portion (44) of the fan blade (34). The extended cavities (66) reduce the weight of each blade (34) and also improve the integrity of each blade (34).
Abstract:
A method is taught for the preparation of abradable seals for gas turbines. The honeycomb of a suitably abradable nickel alloy composition is brazed to the turbine component, and the open cells thereof are smeared closed, such as by grinding, to provide a smooth, dense, and impermeable abradable surface. The surface may be abraded by a cubic boron nitride abrasively tipped blade to form an inexpensive but highly efficient seal.
Abstract:
A silicon capacitive pressure sensor is disclosed that has a glass dielectric material sputter-deposited onto a silicon substrate (140) of the sensor. After deposition of the bulk dielectric material, the glass is patterned and etched to form a pair of concentric rings. An inner ring (141) is of a circular shape, while the outer ring (142) is of an octogonal shape. As compared to prior art dielectric spacers which are of a single ring of relatively wide thickness, the pair of concentric rings disclosed herein significantly reduce the parasitic capacitance of the glass dielectric material, thereby increasing the sensitivity of the sensor.
Abstract:
A self-aligning piston assembly (13) has a piston member (14) having a sidewall (19) for slidable displacement within a bore (12), the piston member having (14) an inner curved surface (22), the piston assembly (13) having an inner race member (23) having means to attach to a connecting member, the inner race member (23) having a curved surface (29) complementary to the inner curved surface (22) and an elastomer member (30) disposed therebetween substantially in the form of a sphere to provide a spherical type mounting of the piston to the connecting member. Utilizing a spherical type mounting, axial rigidity is maintained, yet any side loading which acts through the connecting member of manufacturing tolerances are absorbed through the spherical elastomer to prevent misalignment or cooking of the piston within the bore during stroking. Utilizing the invention, excessive wear and fluid leakage by the piston is avoided since misalignment is absorbed by the elastomer member.
Abstract:
An electropic metrology system uses Moire interferometry to generate contour information on the surface of an object. Interfering coherent beams generate an image on the object's surface that includes a stripe pattern. The surface is viewed with a high resolution camera and digitized using a frame grabber and computer. A reference pattern is generated in software and is mixed with the digitized object surface signals. The mixed signals are filtered to remove signals at the carrier frequency and signals containing the beat frequency indicative of the surface contours are output.