Volume Boosters - ControlAir
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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The Type 600 ratio relay volume booster is designed to use a pnuematic signal to produce an output pressure which has high flow capacity and can be amplified. This unit is most useful for systems requiring the conversion of a low flow control signal to the higher flow requirements of an operating system. Using an independent supply pressure for greater volume, the Type 600 relays up to 50 scfm (1,400 Nl/min) flow capacity to a final control element such as a valve actuator. The standard signal to output ratio is 1:1, however, the Type 600 is also available with an amplified ratio of 1:2, 1:3 and 1:6.
$262.70
Available for Purchase
Subject to factory lead times
The Type 600 ratio relay volume booster is designed to use a pnuematic signal to produce an output pressure which has high flow capacity and can be amplified. This unit is most useful for systems requiring the conversion of a low flow control signal to the higher flow requirements of an operating system. Using an independent supply pressure for greater volume, the Type 600 relays up to 50 scfm (1,400 Nl/min) flow capacity to a final control element such as a valve actuator. The standard signal to output ratio is 1:1, however, the Type 600 is also available with an amplified ratio of 1:2, 1:3 and 1:6.
$246.07
Available for Purchase
Subject to factory lead times
The Type 6000 Volume Booster is a one-to-one signal to output relay that, when used with a positioner/actuator, is designed to increase the stroking speed of control valves. A large input signal change to the volume booster delivers high volume, fast action throttling control. An integral bypass valve provides system stability while allowing normal positioner airflow and normal valve actuation with small input changes. If the volume booster is to be used for on/off control valves, the bypass valve can be closed to optimize stroking speed. The Type 6000 is available in aluminum or 316 stainless steel construction.
$1,879.35
Available for Purchase
Subject to factory lead times
The Type 6000 Volume Booster is a one-to-one signal to output relay that, when used with a positioner/actuator, is designed to increase the stroking speed of control valves. A large input signal change to the volume booster delivers high volume, fast action throttling control. An integral bypass valve provides system stability while allowing normal positioner airflow and normal valve actuation with small input changes. If the volume booster is to be used for on/off control valves, the bypass valve can be closed to optimize stroking speed. The Type 6000 is available in aluminum or 316 stainless steel construction.
Requires Quote
Available for Purchase
Subject to factory lead times
T6000 REPAIR KIT, EPDM
$361.87
Available for Purchase
Subject to factory lead times
T6000 REPAIR KIT, SILICONE
$542.71
Available for Purchase
Subject to factory lead times
The Type 6100 aluminum volume booster is a 1:1 signal to output relays that is utilized in applications that require high forward airflow and exhaust capacities. Typically they are used to increase the throttling speed of large volume valve actuators. They are suitable for either diaphragm or piston actuators. A fixed deadband and adjustable bypass valve combine to allow small incremental downstream adjustment without opening the main booster valve. The bypass valve is used to adjust dynamic response to provide stable operation over a wide range of actuator sizes. Negative Bias adjustment (up to -4 psi) is available to “zero†downstream pressures when using standard signal pressure ranges.
$513.41
Available for Purchase
Subject to factory lead times
The Type 6100 aluminum volume booster is a 1:1 signal to output relays that is utilized in applications that require high forward airflow and exhaust capacities. Typically they are used to increase the throttling speed of large volume valve actuators. They are suitable for either diaphragm or piston actuators. A fixed deadband and adjustable bypass valve combine to allow small incremental downstream adjustment without opening the main booster valve. The bypass valve is used to adjust dynamic response to provide stable operation over a wide range of actuator sizes. Negative Bias adjustment (up to -4 psi) is available to “zero†downstream pressures when using standard signal pressure ranges.
$601.16
Available for Purchase
Subject to factory lead times
The Type 6100 aluminum volume booster is a 1:1 signal to output relays that is utilized in applications that require high forward airflow and exhaust capacities. Typically they are used to increase the throttling speed of large volume valve actuators. They are suitable for either diaphragm or piston actuators. A fixed deadband and adjustable bypass valve combine to allow small incremental downstream adjustment without opening the main booster valve. The bypass valve is used to adjust dynamic response to provide stable operation over a wide range of actuator sizes. Negative Bias adjustment (up to -4 psi) is available to “zero†downstream pressures when using standard signal pressure ranges.
$669.90
Available for Purchase
Subject to factory lead times
T6100 LOW TEMP REPAIR KIT
$220.23
Available for Purchase
Subject to factory lead times
Rapid Stroke Capability in a 316 Stainless Steel Housing. The Type 6200 Stainless Steel Volume Booster is a 1:1 signal to output relay that significantly increase the stroking speed in valve actuation system applications that require high forward airflow and exhaust capacities. Constructed of 316 stainless steel to ensure the best resistance to corrosive environments. The Type 6200 is suitable for either diaphragm or piston actuators. A fixed deadband and adjustable bypass valve combine to allow small incremental downstream adjustment without opening the main booster valve. The bypass valve is used to adjust dynamic response to provide stable operation over a wide range of actuator sizes. Negative Bias adjustment (up to -4 psi) is available to “zero†downstream pressures when using standard signal pressure ranges
$949.23
Available for Purchase
Subject to factory lead times
Rapid Stroke Capability in a 316 Stainless Steel Housing. The Type 6200 Stainless Steel Volume Booster is a 1:1 signal to output relay that significantly increase the stroking speed in valve actuation system applications that require high forward airflow and exhaust capacities. Constructed of 316 stainless steel to ensure the best resistance to corrosive environments. The Type 6200 is suitable for either diaphragm or piston actuators. A fixed deadband and adjustable bypass valve combine to allow small incremental downstream adjustment without opening the main booster valve. The bypass valve is used to adjust dynamic response to provide stable operation over a wide range of actuator sizes. Negative Bias adjustment (up to -4 psi) is available to “zero†downstream pressures when using standard signal pressure ranges
$1,229.24
Available for Purchase
Subject to factory lead times
Rapid Stroke Capability in a 316 Stainless Steel Housing. The Type 6200 Stainless Steel Volume Booster is a 1:1 signal to output relay that significantly increase the stroking speed in valve actuation system applications that require high forward airflow and exhaust capacities. Constructed of 316 stainless steel to ensure the best resistance to corrosive environments. The Type 6200 is suitable for either diaphragm or piston actuators. A fixed deadband and adjustable bypass valve combine to allow small incremental downstream adjustment without opening the main booster valve. The bypass valve is used to adjust dynamic response to provide stable operation over a wide range of actuator sizes. Negative Bias adjustment (up to -4 psi) is available to “zero†downstream pressures when using standard signal pressure ranges
$949.23
Available for Purchase
Subject to factory lead times
T6200 LOW TEMP REPAIR KIT
$303.92
Available for Purchase
Subject to factory lead times
T6200 REPAIR KIT
$254.38
Available for Purchase
Subject to factory lead times
The Type 6500 aluminum volume boosters are 1:1 signal to output relays that are utilized in applications that require high flow capacity. Typically they are used to increase throttling speed of large volume valve actuators. They are suitable for either diaphragm or piston actuators. A fixed deadband and adjustable bypass valve combine to allow small incremental downstream adjustment without opening the main booster valve. The bypass valve is used to adjust dynamic response to provide stable operation over a wide range of actuator sizes.
$1,145.26
Available for Purchase
Subject to factory lead times
The Type 6500 aluminum volume boosters are 1:1 signal to output relays that are utilized in applications that require high flow capacity. Typically they are used to increase throttling speed of large volume valve actuators. They are suitable for either diaphragm or piston actuators. A fixed deadband and adjustable bypass valve combine to allow small incremental downstream adjustment without opening the main booster valve. The bypass valve is used to adjust dynamic response to provide stable operation over a wide range of actuator sizes.
$1,046.33
Available for Purchase
Subject to factory lead times
The Type 6500 aluminum volume boosters are 1:1 signal to output relays that are utilized in applications that require high flow capacity. Typically they are used to increase throttling speed of large volume valve actuators. They are suitable for either diaphragm or piston actuators. A fixed deadband and adjustable bypass valve combine to allow small incremental downstream adjustment without opening the main booster valve. The bypass valve is used to adjust dynamic response to provide stable operation over a wide range of actuator sizes.
$1,145.26
Available for Purchase
Subject to factory lead times
REPAIR KIT, T6500, TALL HOUSING NUT
$323.17
Available for Purchase
Subject to factory lead times
T6500 LOW TEMP REPAIR KIT
$220.23
Available for Purchase
Subject to factory lead times
T6600 LOW TEMP REPAIR KIT
$515.84
Available for Purchase
Subject to factory lead times
The Type 600 ratio relay volume booster is designed to use a pnuematic signal to produce an output pressure which has high flow capacity and can be amplified. This unit is most useful for systems requiring the conversion of a low flow control signal to the higher flow requirements of an operating system. Using an independent supply pressure for greater volume, the Type 600 relays up to 50 scfm (1,400 Nl/min) flow capacity to a final control element such as a valve actuator. The standard signal to output ratio is 1:1, however, the Type 600 is also available with an amplified ratio of 1:2, 1:3 and 1:6.
$262.70
Available for Purchase
Subject to factory lead times
The Type 600 ratio relay volume booster is designed to use a pnuematic signal to produce an output pressure which has high flow capacity and can be amplified. This unit is most useful for systems requiring the conversion of a low flow control signal to the higher flow requirements of an operating system. Using an independent supply pressure for greater volume, the Type 600 relays up to 50 scfm (1,400 Nl/min) flow capacity to a final control element such as a valve actuator. The standard signal to output ratio is 1:1, however, the Type 600 is also available with an amplified ratio of 1:2, 1:3 and 1:6.
$246.07
Available for Purchase
Subject to factory lead times
The Type 6000 Volume Booster is a one-to-one signal to output relay that, when used with a positioner/actuator, is designed to increase the stroking speed of control valves. A large input signal change to the volume booster delivers high volume, fast action throttling control. An integral bypass valve provides system stability while allowing normal positioner airflow and normal valve actuation with small input changes. If the volume booster is to be used for on/off control valves, the bypass valve can be closed to optimize stroking speed. The Type 6000 is available in aluminum or 316 stainless steel construction.
$1,879.35
Available for Purchase
Subject to factory lead times
The Type 6000 Volume Booster is a one-to-one signal to output relay that, when used with a positioner/actuator, is designed to increase the stroking speed of control valves. A large input signal change to the volume booster delivers high volume, fast action throttling control. An integral bypass valve provides system stability while allowing normal positioner airflow and normal valve actuation with small input changes. If the volume booster is to be used for on/off control valves, the bypass valve can be closed to optimize stroking speed. The Type 6000 is available in aluminum or 316 stainless steel construction.
Requires Quote
Available for Purchase
Subject to factory lead times
T6000 REPAIR KIT, EPDM
$361.87
Available for Purchase
Subject to factory lead times
T6000 REPAIR KIT, SILICONE
$542.71
Available for Purchase
Subject to factory lead times
The Type 6100 aluminum volume booster is a 1:1 signal to output relays that is utilized in applications that require high forward airflow and exhaust capacities. Typically they are used to increase the throttling speed of large volume valve actuators. They are suitable for either diaphragm or piston actuators. A fixed deadband and adjustable bypass valve combine to allow small incremental downstream adjustment without opening the main booster valve. The bypass valve is used to adjust dynamic response to provide stable operation over a wide range of actuator sizes. Negative Bias adjustment (up to -4 psi) is available to “zero†downstream pressures when using standard signal pressure ranges.
$513.41
Available for Purchase
Subject to factory lead times
The Type 6100 aluminum volume booster is a 1:1 signal to output relays that is utilized in applications that require high forward airflow and exhaust capacities. Typically they are used to increase the throttling speed of large volume valve actuators. They are suitable for either diaphragm or piston actuators. A fixed deadband and adjustable bypass valve combine to allow small incremental downstream adjustment without opening the main booster valve. The bypass valve is used to adjust dynamic response to provide stable operation over a wide range of actuator sizes. Negative Bias adjustment (up to -4 psi) is available to “zero†downstream pressures when using standard signal pressure ranges.
$601.16
Available for Purchase
Subject to factory lead times
The Type 6100 aluminum volume booster is a 1:1 signal to output relays that is utilized in applications that require high forward airflow and exhaust capacities. Typically they are used to increase the throttling speed of large volume valve actuators. They are suitable for either diaphragm or piston actuators. A fixed deadband and adjustable bypass valve combine to allow small incremental downstream adjustment without opening the main booster valve. The bypass valve is used to adjust dynamic response to provide stable operation over a wide range of actuator sizes. Negative Bias adjustment (up to -4 psi) is available to “zero†downstream pressures when using standard signal pressure ranges.
$669.90
Available for Purchase
Subject to factory lead times
T6100 LOW TEMP REPAIR KIT
$220.23
Available for Purchase
Subject to factory lead times
Rapid Stroke Capability in a 316 Stainless Steel Housing. The Type 6200 Stainless Steel Volume Booster is a 1:1 signal to output relay that significantly increase the stroking speed in valve actuation system applications that require high forward airflow and exhaust capacities. Constructed of 316 stainless steel to ensure the best resistance to corrosive environments. The Type 6200 is suitable for either diaphragm or piston actuators. A fixed deadband and adjustable bypass valve combine to allow small incremental downstream adjustment without opening the main booster valve. The bypass valve is used to adjust dynamic response to provide stable operation over a wide range of actuator sizes. Negative Bias adjustment (up to -4 psi) is available to “zero†downstream pressures when using standard signal pressure ranges
$949.23
Available for Purchase
Subject to factory lead times
Rapid Stroke Capability in a 316 Stainless Steel Housing. The Type 6200 Stainless Steel Volume Booster is a 1:1 signal to output relay that significantly increase the stroking speed in valve actuation system applications that require high forward airflow and exhaust capacities. Constructed of 316 stainless steel to ensure the best resistance to corrosive environments. The Type 6200 is suitable for either diaphragm or piston actuators. A fixed deadband and adjustable bypass valve combine to allow small incremental downstream adjustment without opening the main booster valve. The bypass valve is used to adjust dynamic response to provide stable operation over a wide range of actuator sizes. Negative Bias adjustment (up to -4 psi) is available to “zero†downstream pressures when using standard signal pressure ranges
$1,229.24
Available for Purchase
Subject to factory lead times
Rapid Stroke Capability in a 316 Stainless Steel Housing. The Type 6200 Stainless Steel Volume Booster is a 1:1 signal to output relay that significantly increase the stroking speed in valve actuation system applications that require high forward airflow and exhaust capacities. Constructed of 316 stainless steel to ensure the best resistance to corrosive environments. The Type 6200 is suitable for either diaphragm or piston actuators. A fixed deadband and adjustable bypass valve combine to allow small incremental downstream adjustment without opening the main booster valve. The bypass valve is used to adjust dynamic response to provide stable operation over a wide range of actuator sizes. Negative Bias adjustment (up to -4 psi) is available to “zero†downstream pressures when using standard signal pressure ranges
$949.23
Available for Purchase
Subject to factory lead times
T6200 LOW TEMP REPAIR KIT
$303.92
Available for Purchase
Subject to factory lead times
T6200 REPAIR KIT
$254.38
Available for Purchase
Subject to factory lead times
The Type 6500 aluminum volume boosters are 1:1 signal to output relays that are utilized in applications that require high flow capacity. Typically they are used to increase throttling speed of large volume valve actuators. They are suitable for either diaphragm or piston actuators. A fixed deadband and adjustable bypass valve combine to allow small incremental downstream adjustment without opening the main booster valve. The bypass valve is used to adjust dynamic response to provide stable operation over a wide range of actuator sizes.
$1,145.26
Available for Purchase
Subject to factory lead times
The Type 6500 aluminum volume boosters are 1:1 signal to output relays that are utilized in applications that require high flow capacity. Typically they are used to increase throttling speed of large volume valve actuators. They are suitable for either diaphragm or piston actuators. A fixed deadband and adjustable bypass valve combine to allow small incremental downstream adjustment without opening the main booster valve. The bypass valve is used to adjust dynamic response to provide stable operation over a wide range of actuator sizes.
$1,046.33
Available for Purchase
Subject to factory lead times
The Type 6500 aluminum volume boosters are 1:1 signal to output relays that are utilized in applications that require high flow capacity. Typically they are used to increase throttling speed of large volume valve actuators. They are suitable for either diaphragm or piston actuators. A fixed deadband and adjustable bypass valve combine to allow small incremental downstream adjustment without opening the main booster valve. The bypass valve is used to adjust dynamic response to provide stable operation over a wide range of actuator sizes.
$1,145.26
Available for Purchase
Subject to factory lead times
REPAIR KIT, T6500, TALL HOUSING NUT
$323.17
Available for Purchase
Subject to factory lead times
T6500 LOW TEMP REPAIR KIT
$220.23
Available for Purchase
Subject to factory lead times
T6600 LOW TEMP REPAIR KIT
$515.84
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.