Abstract: Disclosed herein is a dual density disc comprising a dense outer tube comprising alumina having a purity of greater than 99%; and a porous core comprising alumina of a lower density than a density of the dense outer tube; wherein the porous core has an alumina purity of greater than 99%. Disclosed herein too is method comprising disposing in a dense outer tube a slurry comprising alumina powder and a pore former; heating the dense outer tube with the slurry disposed therein to a temperature of 300 to 600° C. to activate the pore former; creating a porous core in the dense outer tube; and sintering the dense outer tube with the porous core at a temperature of 800 to 2000° C. in one or more stages.

Abstract: A reciprocating machine component, such as a piston of an internal combustion engine or a compressor, is provided with bearing pads for transmitting lateral thrust to an associated guide surface, such as a cylinder or liner. The bearing pads are mounted such that they tilt during reciprocation in order to provide a wedge-shaped lubricant film between the pad and the surface. The mounting is also such as to ensure that the direction of tilt of the pads changes with the direction of reciprocation.

Abstract: A scraper ring system for removing fluid from a relatively moving cylindrical surface such as a piston rod which comprises a series of overlapping blades or leaves which are pressed against the rod surface at an acute angle either by a garter spring or when the blades are part of a continuous strip, by the natural resilience of the strip and blades. The blades are located in a housing and passages are provided for the discharge of any removed fluid.

Abstract: An annular seal against the flow of fluid along a shaft sleeve (5) includes a rigid ring (15) with flexible flanges (10,11) respectively radially inwards and outwards of the ring (15), one of which carries a sealing contact lip (9) against the shaft sleeve (5) while the other is connected to a surrounding mounting (13).

Abstract: A multi-pad thrust bearing has the pads mounted on a carrier through a hydrostatic oil pressure cushion regions, the oil in which has been pressurized hydrodynamically by rotation between the pad bearing surfaces and the load surface; the oil is led through the bearing pads to rear cavity where the oil cushion is established.