.~ Sequentially progressive opening or closing of plural valves {4}
630.18
.~.~ Screw-actuated differential valves
DEFINITION
Classification: 137/630.18
(under subclass 628) Systems in which (1) at least one of the valves is screw actuated and the remaining valve or valves are biased so that as the screw is actuated one of the valves is moved to or from its seated position and further actuation of the screw in the same direction then moves the remaining valve or valves, against the bias, to or from the seated position, or (2) both valves are screw actuated by a common
operator and a lost motion connection is provided between the two movable valve elements or between one of the valve elements and its screw actuator.
