US Patent 11946420 Fuel systems having thermal recirculation

A fuel system includes a main pump assembly. The main pump assembly has a main fuel pump connected to an input line, a recirculation pump connected to the input line, and a fuel recirculation system. A recirculation control includes a first selector valve in fluid communication with an outlet line of the recirculation pump, with a recirculation return line connected to return fuel to the input line, and with an inter-valve line. The recirculation control includes a second selector valve in fluid communication with the inter-valve line, with a back-up line connecting the second selector valve to a main fuel control, and with a cooler recirculation line connected to supply the one or more coolers.