Abstract
A cleaning head for a cleaning system for use in cleaning a fluid conduit for transporting hydrocarbons and/or a fluid conduit in a hydrocarbon wellbore, comprises a body defining an outer surface having a cross-section which is configured to match, or be comparable to, a cross-section of an inner surface of the fluid conduit. The body defines a jetting fluid flow path extending from a jetting fluid input port to a jetting fluid output port, and wherein the body defines a bypass fluid flow path extending from a bypass fluid input port to a bypass fluid output port, the bypass fluid flow path being separate from the jetting fluid flow path. The cleaning head comprises a jetting head defining one or more jetting apertures, wherein the jetting head is coupled to the jetting fluid output port so that the one or more jetting apertures are in fluid flow communication with the jetting fluid flow path. The cleaning head comprises a variable aperture valve in the bypass fluid flow path, the variable aperture valve defining a variable aperture which varies in response to a variation in fluid flow rate through the bypass fluid flow path.