Level gauge for container holding opaque bottle or flask containing liquid has membrane at bottom and has double sides containing indicator fluid with ring on top

摘要

The bottle (1) may be an aluminum flask containing liquid refreshment. The base of the flask rests on a membrane (3) containing an indicator fluid. The weight of the flask and its contents forces fluid out of the membrane into the transparent double walls of the container (2). A ring (4) floats on the surface of the fluid to act as an indicator of the height of the surface and prevent spillage.