Abstract: A method of producing a filter unit, such as an air/oil separator, having a tubular filter element bonded at one end to an end cap, is proposed. The method includes the steps of: providing a tubular filter element and an end cap; melting a portion of the end cap; and embedding an end of the filter element into the melted portion of the end cap. The melted portion, on cooling, solidifies to bond the tubular filter element to the end cap. The end cap can be formed of thermoplastic containing an electrically conductive filler. The end cap can be formed of a thermoplastic having a melting point of at least 180 C. The method may further include, after the embedding step, a step of forcing melted thermoplastic from the melted portion radially against a side wall of the tubular filter element.

Abstract: A regenerative adsorption gas dryer has a wet gas inlet, first and second drying towers, and a dried gas outlet. The inlet, towers and outlet are arranged such that, in use, a flow of purge gas regenerates an off-stream one of the towers, while a stream of wet gas from the wet gas inlet enters an on-stream one of the towers to exit that tower as a stream of dried gas which then continues to the dried gas outlet. The roles of the off-stream and on-stream towers are reversible. The dryer further has a first check valve for controlling a stream of dried gas between the first drying tower and the dried gas outlet, and a second check valve for controlling a stream of dried gas between the second drying tower and the dried gas outlet.

Abstract: An adsorption gas dryer has a first drying tower and a second drying tower each having a first port and a second port through which gas can pass into or out of the tower, a first manifold and a second manifold connected respectively to the first and the second ports of both towers, the manifolds each including integral gas passages, each port of the towers being in communication with a gas passage, and the manifolds each including at least one integral valve seat upon which a valve actuator is mounted to constitute a valve for controlling flow of gas through the gas passages, wherein the second manifold has two exhaust valves for controlling purge gas.