pA rotary plug valve has a tapered plug received within a frusto-conical chamber in a valve housing. A liner between the plug and chamber wall comprises a rigid metal cage partly enclosed by plastics material to provide a seal with the plug and the chamber wall with the through passage through the liner being defined by flanged portions of the metal cage. The liner and plug are removable as a unit from the chamber in the valve housing. Preferably the plastics material is moulded about the cage and is keyed to the cage by portions thereof extending through apertures of the cage./p[US4410003A]
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