Pneumatic Boosting Cylinder vs. Hydraulic Cylinder: Which One is Better for Your Industry?

When a machine needs more force than an ordinary air cylinder can give, there are two common routes: an air-hydraulic boosting cylinder that runs on compressed air, or a hydraulic cylinder driven by a hydraulic power unit. Both deliver hydraulic force, but they get there in different ways, and each suits a different kind of job.

What Is an Air-Hydraulic Boosting Cylinder?

A boosting cylinder uses compressed air on a large piston to drive a much smaller plunger, which pressurises hydraulic oil in a small, closed circuit. The output oil pressure equals the air pressure multiplied by the area ratio (the boost ratio). The result is hydraulic-level force from ordinary shop air, with no pump, motor or oil tank.

How it works

1. Compressed air enters the air chamber and pushes the large piston.
2. The piston drives the small plunger, raising the oil pressure by the boost ratio.
3. The pressurised oil drives the working piston or an external hydraulic cylinder.
4. When the air is switched, the piston returns and the oil flows back, ready for the next cycle.

Strengths

• No hydraulic power unit: runs on the plant's existing compressed air.
• Works only when actuating: uses no air and generates no heat on standby.
• Compact: high force from a unit that mounts directly on the machine.
• Simple force setting: output follows the supply air pressure, so a regulator sets the force.

Limitations

• Limited oil volume per stroke: best suited to short, high-force actions rather than long hydraulic strokes.
• Depends on the air supply: force drops if air pressure drops, so a stable, dry supply matters.
• Contains oil: the oil circuit is small and sealed, but it still needs to be checked and topped up.

What Is a Hydraulic Cylinder With a Power Unit?

A hydraulic power unit uses an electric motor and pump to supply pressurised oil from a tank, through valves, to the hydraulic cylinder. Because the pump can deliver oil continuously, the cylinder can move long strokes at controlled speeds and hold high force for long periods.

Strengths

• Continuous high force: suited to presses, long strokes and heavy loads.
• Speed and position control: flow and directional valves give fine control over motion.
• Stiff motion: oil is almost incompressible, so the cylinder holds position firmly under load.

Limitations

• Needs a power unit: motor, pump, tank, piping and often cooling, which take space and add cost.
• Runs on electricity: the pump motor draws power and produces heat while it runs.
• More maintenance: a larger oil volume to filter, change and check for leaks.

Side-by-Side Comparison

• Power source: boosting cylinder, compressed air; hydraulic cylinder, electric motor and pump.
• Best for: boosting cylinder, short high-force actions such as tool unclamping, clamping and pressing; hydraulic cylinder, long strokes, continuous duty and heavy loads.
• Equipment needed: boosting cylinder, the booster only; hydraulic cylinder, a complete power unit.
• Oil volume: boosting cylinder, small and sealed; hydraulic cylinder, a full tank.
• Force setting: boosting cylinder, air regulator; hydraulic cylinder, relief and pressure valves.

A Middle Option: Air-Driven Hydraulic Pumps

Where a machine needs hydraulic pressure more like a power unit, but without an electric pump, an air-driven hydraulic pump such as HINAKA's AHP unit produces hydraulic pressure from compressed air. The AHP received the first Excellence in Energy Saving Award for fluid power products in Taiwan.

Which Should You Choose?

• Choose a boosting cylinder when you need high force over a short stroke and want to avoid a hydraulic power unit, for example spindle tool unclamping or pressing and clamping on automation equipment.
• Choose a hydraulic cylinder with a power unit when you need long strokes, continuous heavy duty or precise speed control.

HINAKA's Range

• Boosting cylinders: APT2 (1.8 to 15 tonnes) and APT (19 to 106 tonnes).
• Boosters: APF2, and the BPF series for spindle unclamping.
• Air-driven hydraulic pump: AHP.
• Hydraulic cylinders: JIS-standard 15B (14 MPa), 5H (5 MPa) and the compact HJ2.

Contact us with the force, stroke and cycle rate your machine needs, and we will help you choose the right approach.

---

Related Articles

5 Reasons to Choose a Boosting Cylinder for Your Industrial Needs

AHP Air-driven Hydraulic Power Unit: The New Trend and Overview of Energy-Efficient Industrial Hydraulics

15B, 5H or HJ2? Choosing Between HINAKA's JIS-Standard Hydraulic Cylinders