The Fairchild Model 4800 Volume booster is specially designed to be used in conjunction with valve positioner on large control actuator to provide faster response than possible with the valve positioner alone.
Features:

• Fixed dead band between the operation of the supply valve and exhaust valve providing Accurate and stable final positioning of the valve.
• Integral bypass needle valve to optimize response time and stability.
• Soft seat supply and exhaust valves.
• Provide efficient leak free operation and prevents hunting when used with modern electronic feed & bleed type positioners Pressure balanced supply valve.
• Maintains deadband specification preventing changes in control
• Characteristics when supply pressure changes. Damped diaphragm control chamber
• Protects valves from damaging oscillation under high flow conditions.