Abstract: A valve assembly (1, 12, 21, 31, 44, 52, 60) includes a hollow tube (2). The valve assembly (1, 12, 21, 31, 44, 52, 60) also includes a first set of one or more valves (3) 5 arranged within the hollow tube (2). The first set of valves (3) is configured to permit sliding passage of a substantially cylindrical object (4). The valve assembly (1, 12, 21, 31, 44, 52, 60) also includes a second set of valves (5) arranged within the hollow tube (2) and spaced apart from the first set of valves to (3) define a chamber. The second set of valves (5) are configured to permit sliding passage of the cylindrical object (4). The 10 valve assembly (1, 12, 21, 31, 44, 52, 60) also includes one or more ultraviolet light sources (10) within the chamber (6) and/or a first port (13) connecting the chamber (6) to the exterior of the hollow tube (2) and configured for connection to a fluid flow path (14) for supply and/or extraction of fluid (19).