(under subclass 269) Apparatus including fluid flow control means for varying the flow of the fluid being pumped, said means being operated by sensing the occurrence of a condition or change in condition.
(1) Note. For a further definition of what constitutes the occurrence of a condition or a change in condition see the definition and notes of subclass 279 of this class.
(2) Note. This definition does not include a distributor for the pump formed by relatively rotating parts (e.g., disc valve) in which the relatively rotating parts are biased into sealing engagement by springs or the like which could yield to allow separation of the valve ports and permit escape or by-pass of pump fluid.
