Accelerator valve
The acceleration valve is a component of modern compressed air brakes on railways . In addition to the rapid braking accelerator, it serves to shorten the application time of the brakes .
In the event of a strong pressure drop in the main air line (HLL), this valve opens against a spring force and connects the main air line to the brake cylinder chamber via a check valve , where it immediately increases the brake pressure.
The acceleration valve uses the pressure difference between the main air line and the lower brake pressure required in the brake cylinder of 1.5 bar. When the pressure in the main air line drops from 5 bar to below 3 bar, the acceleration valve opens and fills the brake cylinder until it has reached the same pressure against the rapidly falling pressure gradient in the main air line. The check valve then prevents the brake cylinder pressure from dropping otherwise. The acceleration valve superimposes the normal pressure build-up in the brake cylinder, which is controlled by the control valve , to accelerate .