Vibration guide structures at top and bottom of flow-sensing disc provide full support to assembly.Top guide includes a snubber to minimize vibration.Built-in Check Valve Spring-loaded against seat,the flow-sensing disc acts as a main flow check valve. Bypass Multistage Pressure Letdown,prevent from cavitation.The valve provides economical and reliable protection against low and reverse flow.By combining the functions of main line check valve,flow sensing element,bypass flow control,bypass pressure reduction,pulsation dampener and bypass line check valve,the valve eliminates at least seven components neccssary with a conventional system.The valve operates without air or electric power and is easily installed with three connection. Typical safety equipment installation on a tank is illustrated in above figure. Most tanks will have provision for a pressure/vacuum relief valve, an emergency relief valve(or emergency relief manhole) and a gas blanket regulator.