Abstract: An apparatus for centrifugal casting of hollow articles in particular pipes. The apparatus has an elongate generally cylindrical hollow mould with a center conductor extending along the longitudinal axis so that the combination acts as a coaxial waveguide. A microwave source and waveguide system are provided to direct substantially TEM mode radiation into one end of the mould. The mould and center conductor are terminated at the other end by a short circuit to microwave radiation so that standing waves are established in the mould. The invention also provides a method for centrifugal casting of such articles in which a casting composition is placed in a hollow rotating mould and microwave radiation is directed into the mould to heat the casting composition.

Abstract: To ensure that a socket formed on a pipe-end in plastically deformable condition is in no part thinner than the pipe material out of which it is made, the pipe-end is first enlarged in diameter and encased within a contour die formed as envelope for the external shape required of the socket. The enlarged pipe-end is then longitudinally compressed to thicken it and internally formed so as to smooth the internal surface of the pipe-end and impose on it the internal shape and dimensions required of the socket. The required socket shape preferably includes a circumferential groove to house a resilient sealing ring.

Abstract: To ensure that a socket formed on a pipe-end in plastically deformable condition is in no part thinner than the pipe material out of which it is made, the pipe-end is first enlarged in diameter and encased within a contour die formed as envelope for the external shape required of the socket. The enlarged pipe-end is then longitudinally compressed to thicken it and internally formed so as to smooth the internal surface of the pipe-end and impose on it the internal shape and dimensions required of the socket. The required socket shape preferably includes a circumferential groove to house a resilient sealing ring.

Abstract: This invention relates to apparatus for the extraction of solids from a liquid slurry or suspension of a type in which a reduced pressure chamber applies suction to a zone on one side of a sieve surface whereby solids may be urged against a corresponding zone on the other side and the liquid is urged to flow through the sieve into the chamber. The invention provides means for transporting liquid from the chamber in discrete amounts while substantially maintaining reduced pressure in the chamber. In preferred embodiments the sieve is cylindrical and rotates, vanes are attached to the chamber side of the sieve carry the water out of the chamber in intervane spaces, while slipper pads provide a seal with vane tips to maintain reduced pressure in the chamber.