Blanket wash system with sub-ambient pressure circulation

摘要

An enhanced system for cleaning a component, such as a blanket, of a printing press in one embodiment provides circulation of wash mixture around a path in such a way that pressure of fluid in the supply line can never exceed ambient pressure. This may be achieved, for example, by utilizing a pump disposed in the return line (rather than in the supply line). Another embodiment provides a spray arrangement for spraying wash mixture onto the component to be cleaned. The spray arrangement has nozzles that are in communication with a feed region (such as the interior of a spray bar) and an isolation valve arrangement for in an open state permitting and in a closed state preventing fluid pressure transmission from the rest of the system to the feed region. A pressure arrangement modifies fluid pressure in the feed region when the isolation valve arrangement is in a closed state. The pressure may be modified so that when the spray arrangement is being prepared for spraying, the pressure is increased above ambient pressure. At other times, the pressure may be below ambient pressure. The pressure arrangement may be realized by a cylinder-piston system, wherein the piston is biased in a first direction to increase the pressure and in a second direction to decrease the pressure.