The fluid replenisher consists of tank 1, connected to the brake cylinder and filled partly with liquid and partly with air. Upon recoil, valve 3, actuated by spring 2 and compressed air, closes and prevents flow of liquid into the brake cylinder. At the end of the counterrecoil, piston 4 pushes back valve 3 and the surplus volume of liquid, due to its heating during intensive firing, is discharged into the replenisher. As the liquid cools, its volume decreases and liquid is forced out of the replenisher into the braking cylinder.
$3782$SHP,FD$