Abstract: The system comprises a pair of error checking processors connected in a master/slave configuration such that the slave receives inputs and outputs of the master, mimics operation of the master based on the inputs to produce mimicked outputs, compares the mimicked outputs with the master outputs and indicates an error condition if the mimicked outputs do not equal the master outputs. A checking circuit forces a difference between the mimicked output and the master output and determines if the master slave configuration accurately determines the presence of the forced error.

Abstract: A method and apparatus for transferring liquid from a first vessel to a second vessel. The second vessel communicates with the first vessel at a location beneath the surface of the liquid contained therein and means are provided for passing vapor present above the surface of said liquid to a heating zone where the vapor is heated to a temperature above the boiling point of the liquid. The heated vapor is then contacted with the surface of said liquid by means provided therefor. As a result of said contact, the surface liquid is caused to boil, thereby increasing the pressure above said surface, this increased pressure causing movement of liquid from the first vessel to the second vessel.