Abstract: An air cooled ultraviolet dryer comprises a lamp (6) mounted within a reflector (1) and supported within a housing (2). The mouth of the reflector is closed off with a tubular heat barrier comprising contiguous tubes (10) which are transparent to UV light. Cooling is effected by passing cooling air into space (3) between the housing (2) and the reflector lamps along tubes (10), preferably by applying suction to the outlet at one end of the housing and causing air to flow transversely over the lamp and through the tubes (10).

Abstract: In the manufacture of roof tiles comprising extruding a continuous shaped ribbon of tile forming material onto a succession of pallets, and cutting the ribbon where pallets adjoin to form individual green state tiles on pallets, there is performed the step of causing a cutting tool to engage with the upper surface of the ribbon only for part of the length of each pallet whereby a recess is formed in the upper surface of each tile. In a particular embodiment the recess is a channel cut in the tile at a location immediately downstream of the extruding step. The recess is also subsequently smoothed by applying a smoothing roll thereto.

Abstract: Hardmetal lamina are cut, by a process known as electrical discharge machining, from a block of hardmetal using a wire electrode. The laminae so formed may then be attached by adhesive or epoxy resin to a suitable base in order to form a hard metal surfaced tool. Provision is made for preventing this hardmetal from shearing from its mounting, and also to remove any heat generated within the hardmetal. Reference is made especially to using the above construction for a `slipper` within a tile producing machine. The word `hardmetal` is used to denote powdered carbides of the transition metals, cemented into solid masses by a matrix of a metal of a lower melting point.