Patent ID: 11946420
Assignee: HAMILTON SUNDSTRAND CORPORATION
Field: Engines, pumps, turbines (Mechanical engineering)
Classification: CPC F | IPC F

Claim 0:
1. A fuel system, comprising:
a main pump assembly having:
a main fuel pump connected to an input line and configured to pump fuel to a main fuel control via a main fuel control line;
a recirculation pump connected to the input line;
a fuel recirculation system connected to an outlet line of the recirculation pump and upstream of the main fuel control, the fuel recirculation system configured to select a mode from a plurality of modes, wherein the plurality of modes include a recirculation mode and a backup mode, wherein the fuel recirculation system is configured to recirculate fuel from the recirculation pump to a tank through one or more coolers in the recirculation mode, and provide fuel to the main fuel control in the backup mode; and
a recirculation control configured to select between the recirculation mode and the backup mode, wherein the recirculation control includes:
a first selector valve in fluid communication with the 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, wherein the first selector valve is configured to select between connecting the outlet line of the recirculation pump with either the recirculation return line or with the inter-valve line; and
a second selector valve in fluid communication with the inter-valve line, with a back-up line connecting the second selector valve to the main fuel control, and with a cooler recirculation line connected to supply the one or more coolers, wherein the second selector valve is configured to select between connecting the inter-valve line with either the back-up line or with the cooler recirculation line.