The Fuel Gel flow regulator is a device, most likely used by the Reptilicus, to regulate the flow of Fuel Gel throughout the surrounding areas. Samus encounters and must activate one in the Gel Processing Site by using the pumping station on it.
"Fuel Gel flow regulator is inactive. Pump must be primed to activate regulator."
"Fuel Gel flow regulator is not engaged. Igniting the Fuel Gel may force it into position."
"Flow regulators engaged. System is at nominal. Maintenance tunnel open."