Volume Boosters
Volume boosters increase air flow to a pneumatic actuator without changing the control signal. They let large control valves stroke quickly and accurately, which matters for anti-surge, emergency shutdown and fast-acting control loops.
How They Work
A positioner or controller sends a small pneumatic signal to the booster. The booster matches that signal pressure while supplying much higher flow from the air supply, filling and exhausting the actuator far faster than the positioner could alone.
Key Considerations
- Flow capacity (Cv) – sized to the actuator volume and stroke time you need
- Bypass adjustment – prevents instability with positioners
- Materials – aluminum or stainless for corrosive environments
- Connection sizes – match supply and actuator tubing
Proper tuning is important. Too much boost can cause overshoot and cycling. Centro can help you size volume boosters and integrate them with your valve positioners.
Related categories: Actuation and Engineered Products | Actuators | Washdown Systems | Regulators | Transducers
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VOLUME BOOSTER 1:1 W/OPTIONS
$318.07$394.41
Available for Purchase
Subject to factory lead times
VOLUME BOOSTER 1:1 W/OPTIONS
$302.95$375.66
Available for Purchase
Subject to factory lead times
VOLUME BOOSTER 1:1 W/OPTIONS
$306.88$380.53
Available for Purchase
Subject to factory lead times
VOLUME BOOSTER 1:1 W/OPTIONS
$302.95$375.66
Available for Purchase
Subject to factory lead times
VOLUME BOOSTER 1:1 W/OPTIONS
$318.07$394.41
Available for Purchase
Subject to factory lead times
VOLUME BOOSTER 1:1 W/OPTIONS
$306.88$380.53
Available for Purchase
Subject to factory lead times
VOLUME BOOSTER W/GAGE
$306.88$380.53
Available for Purchase
Subject to factory lead times
VOLUME BOOSTER 1:1 W/OPTIONS
$318.07$394.41
Available for Purchase
Subject to factory lead times
VOLUME BOOSTER 1:1 W/OPTIONS
$302.95$375.66
Available for Purchase
Subject to factory lead times
VOLUME BOOSTER 1:1 W/OPTIONS
$306.88$380.53
Available for Purchase
Subject to factory lead times
VOLUME BOOSTER 1:1 W/OPTIONS
$302.95$375.66
Available for Purchase
Subject to factory lead times
VOLUME BOOSTER 1:1 W/OPTIONS
$318.07$394.41
Available for Purchase
Subject to factory lead times
VOLUME BOOSTER 1:1 W/OPTIONS
$306.88$380.53
Available for Purchase
Subject to factory lead times
VOLUME BOOSTER W/GAGE
$306.88$380.53
Available for Purchase
Subject to factory lead times
FAQS
- A volume booster is a pneumatic relay device that amplifies the air flow capacity of a control signal to increase the stroking speed of a valve actuator. When a positioner sends a small-volume air signal to move a large actuator, the limited flow rate of the positioner alone can result in slow valve response — the actuator takes too long to fill or exhaust because the positioner cannot supply air fast enough. A volume booster solves this by using the positioner's output as a pilot signal and independently supplying high-volume air from a separate supply line directly to the actuator. The result is significantly faster valve stroking speed without sacrificing the positioner's control accuracy. Volume boosters are essential in applications where large actuators must respond quickly to process changes, such as turbine bypass valves, compressor anti-surge systems, and fast-acting safety shutoff valves. They are available in 1:1 ratio (output equals input) and amplified ratios (1:2, 1:3, 1:6) for applications where the output pressure needs to be higher than the input signal.
- A volume booster improves response time by dramatically increasing the volume of air that can flow to and from the actuator during each stroke. Without a booster, the positioner is the only device supplying air to the actuator, and positioners are designed for accuracy, not high flow capacity — a typical positioner may supply 3 to 10 scfm, which is adequate for small actuators but insufficient to quickly fill a large-volume actuator cylinder. A volume booster can relay 50 scfm or more, reducing the time it takes to pressurize or exhaust the actuator by a factor of five to ten or more. The booster monitors the positioner's output signal and tracks it in a 1:1 ratio (or an amplified ratio if specified). When the positioner calls for a large change in actuator pressure, the booster opens its main valve and delivers high-volume air from the independent supply. For small, incremental signal changes, an adjustable bypass valve allows the positioner's air to pass through directly, maintaining smooth, stable control without triggering the booster's high-flow response.
- The ratio describes the relationship between the input signal pressure and the output pressure delivered to the actuator. A 1:1 volume booster produces an output pressure equal to the input signal — if the positioner sends 9 psi, the booster delivers 9 psi to the actuator, but at a much higher flow rate than the positioner alone could provide. This is the most common configuration and is used when the positioner and actuator operate on the same pressure range. An amplified ratio booster (such as 1:2, 1:3, or 1:6) produces an output pressure that is a fixed multiple of the input signal — for example, a 1:3 booster receiving a 5 psi input delivers 15 psi output. Amplified ratio boosters are used when the actuator requires a higher operating pressure than the positioner can deliver, or when the control signal range is lower than the actuator's pressure range. This is common in systems where the positioner outputs a standard 3–15 psi signal but the actuator needs 0–60 psi or higher to generate sufficient torque.
- The decision depends on the actuator volume, the required response time, and the level of control precision needed. A larger positioner with higher flow capacity can handle moderately sized actuators without a booster, but positioners are precision instruments — increasing their flow capacity significantly adds cost and complexity, and very high-flow positioners may sacrifice some control resolution. A volume booster is the more practical and cost-effective solution when the actuator volume exceeds the positioner's flow capability, which is common with large butterfly valves, ball valves 6 inches and above, or any actuator with a large air volume chamber. The booster handles the high-flow demand while the positioner maintains control accuracy. Volume boosters are also the standard approach for emergency or safety applications where the fastest possible stroking speed is required — no positioner alone can match the flow capacity of a dedicated booster in these high-demand scenarios. As a general guideline, if the actuator takes longer than your process can tolerate to reach its target position with the positioner alone, add a volume booster.
- Volume boosters are typically available in aluminum and 316 stainless steel body constructions. Aluminum is the standard choice for general industrial service — it is lightweight, cost-effective, and suitable for clean, dry instrument air in non-corrosive environments. Most plant air systems with properly maintained filter-regulator-lubricator (FRL) units are compatible with aluminum boosters. Stainless steel (316SS) is specified for corrosive environments, offshore and marine installations, chemical processing plants where airborne chemicals may attack aluminum, and applications where the air supply may contain trace corrosive contaminants. Stainless steel boosters cost more but provide significantly longer service life in harsh conditions. Internal components — diaphragms, O-rings, and seat materials — are also selected based on the operating environment and temperature range. For most standard indoor industrial applications with clean instrument air, an aluminum volume booster provides reliable, long-lasting service at the best value.