Abstract: A brush seal having bristles of a diameter of between 0.005 mm to 0.02 mm manufactured from an oxidation resistant metal alloy including between 10 and 60% cobalt as a base alloy having no more than 1% creep after a 1000 hours at 650° C. at a pressure of at least 345 Pa.

Abstract: A rotary valve assembly comprising a housing defining a bore and a valve member mounted for rotation therewithin. The housing defines an opening and the valve member has a port which comes into and out of registration as the member rotates. Lubricant is supplied between the two members and sealing means are provided around the opening in the housing to effect a seal with the valve member. The sealing means includes a sealing element disposed in at least one groove formed in the housing parallel to the axis of the bore, the element being urged into contact with the valve member.