US Patent 11680549 Fluid injection systems for fluid line purging

A fluid injection system can include a main flow line, a primary flow line connected to the main flow line, a primary flow valve disposed on the primary flow line and configured to selectively allow injectant flow to the primary flow line, a secondary flow line connected to the main flow line, and a secondary flow valve disposed on the secondary flow line and configured to selectively allow injectant flow to the secondary flow line. The system can include a primary purge branch in fluid communication with the primary flow line and connected to a purge gas line, a primary purge valve disposed in the primary purge branch between the primary flow line and the purge gas line, a secondary purge branch in fluid communication with the secondary flow line, and a secondary purge valve disposed between the purge gas line and both of the primary purge branch and the secondary purge branch.