A quick-release valve is used to quickly expel air from a regulated device. Rather than requiring exhaust air to return and exhaust through the control valve, it is usually situated near to the controlled device. This reduces the amount of time it takes for the product to be released.
A quick-release valve on trucks was created to accelerate the discharge of air from brake chambers, allowing the brakes to release more quickly. As air travels toward the brake chamber as the brake pedal is pushed, it passes through the fast release valve, which is placed near the chamber.