(under subclass 238) Systems in which the cleaning device includes a means for causing a fluid to flow in the reverse direction to the normal flow path to remove undesirable material from the system or parts thereof.
SEE OR SEARCH THIS CLASS, SUBCLASS:
102+, for reversing valves in supply and exhaust type self-regulating systems, especially subclasses 103+ for the suction pulsator type and 106 for 4-way valve systems.
207.5, for diverse fluid containing pressure systems having means to return fluid contained in the system to the source of supply.
249+, and 309+, for reversing valves of the regenerative furnace type.
