Abstract: A sequential controller is provided for sequencing multiple electric loads such electric pumps. That is, for each cycle the next load is designated as the lead load in a round-robin fashion. The controller uses cost effective electro-mechanical relay logic an thus avoids conventional solid state technology. In order to sequence the loads on each successive cycle, the electro-mechanical relay connected to the sensors comprises a double-throw contact set. The double-throw contact set comprises two complementary contacts, both of which alternate between normally open and normally closed on each successive cycle. In this manner one each successive cycle, the pumps designated as the lead pump and the lag pump automatically alternate in a round-robin fashion. Further, when the lead pump is disabled the lag pump is immediately actuated without disruption of service.

Abstract: Improvements are disclosed for liquid flow drainage control in gravity type systems such as sewage septic tank systems. A plastic cap which is insertable into the ends of the drainage pipes that project into a distribution box is formed with an end face and a cylindrical body. The end face is generally circular having a larger diameter than the outer diameter of the drainage pipes into which the cap is to be inserted. The outer periphery of the end face is provided with an interdigital or scalloped pattern to facilitate easy gripping even in the most adverse conditions. The end face is further provided with an eccentric discharge hole which is located along a diameter of the end face so that the hole is always some distance from the interior surface of the cylindrical body so that the hole forms a weir to the inlet of the drainage pipe into which the end cap is inserted. The eccentric hole is provided with an outwardly projecting flange which, in cooperation with a spirit level, is used for rough leveling.