Air pressure boosters – booster regulators 2× to 4×

Up to 4× higher pressure

A pressure booster (booster regulator) raises the pressure of compressed air from the air network 2× to 4× – for example from 6 bar to 12 bar – only for the machine or tool that needs the higher pressure. It needs no electricity or cables: it is driven by the compressed air itself.

We offer genuine SMC VBA pressure boosters – 6 series with an outlet pressure of up to 20 bar and flow rates of 70 to 1,900 l/min – together with SMC VBAT air tanks, silencers, pressure gauges and service kits.

What a pressure booster is used for

Most machines manage with a pressure of around 6 bar, but a single press, clamp or test fixture may need 10 or 15 bar. Instead of a high-pressure compressor and a second air network, all it takes is a pressure booster fitted right at that machine. The whole air network can then run at a lower pressure – which saves energy and reduces leakage.

A booster also helps where a cylinder lacks force and a larger one will not fit into the machine: double the pressure gives the same cylinder double the force. Note the difference: pressure regulators only reduce pressure – higher pressure can only be produced by a booster.

• raises pressure 2× (VBA11A series 2× to 4×) without electricity or cables
• the outlet pressure is set with a handle, as on a regulator; on the VBA22A remotely by air pressure
• outlet up to 20 bar, inlet 1 to 10 bar
• higher pressure only at the machine that needs it – the rest of the air network at a lower pressure
• little heat and no sparks: suitable even where you do not want an electric compressor
• a built-in inlet strainer protects the valves from dirt
• a high-efficiency silencer reduces exhaust noise – according to SMC, the new model has a noise level 13 dB(A) lower than its predecessor
• the SMC air tank bolts directly underneath the booster

Six series of SMC VBA pressure boosters

The series differ in size (connection and flow rate), boost ratio, maximum outlet pressure and adjustment. Each series has one product page, where you choose the version without accessories, with pressure gauges and silencer, or with pressure gauges and high-efficiency silencer.

Flow rate according to SMC at an inlet and outlet pressure of 5 bar – at a higher boost ratio, the booster delivers less air. Weight without accessories according to SMC. Dimensions without silencer.

How to choose a pressure booster

1. Outlet pressure. Find out what pressure the machine needs. Up to 10 bar, all series are suitable; up to 16 bar, the large VBA43A series; and up to 20 bar, the small VBA10A and VBA11A series.
2. Boost ratio. Divide the required pressure by the network pressure. Up to double, the standard series are sufficient; for three to four times, there is the VBA11A.
3. Flow rate. Add up the air consumption downstream of the booster and choose the size: the VBA10A delivers up to 230 l/min, the VBA20A and VBA22A 1,000 l/min, the VBA43A 1,600 l/min and the VBA40A 1,900 l/min. The higher the boost ratio, the less air – the curves in the SMC catalogue show this in detail.
4. Inlet air. The booster uses part of the air to drive itself. The compressor must therefore supply about 2.2× more air than the booster delivers at the outlet (about 3.7× for the VBA11A at a boost ratio of 4×).
5. Air tank. If the machine draws air intermittently (cylinder, clamp) or pressure pulsation is a problem, install an air tank downstream of the booster. The air tank must withstand the maximum outlet pressure of the booster.

Calculation example according to SMC

A double-acting cylinder ⌀ 100 mm is to work at a pressure of 8 bar at a speed of 200 mm/s; the air network has 5 bar. The cylinder consumes about 841 l/min, while a booster of size VBA20A delivers about 600 l/min at these pressures – the missing air is supplied by the air tank.

Required air tank volume: V = (consumption − booster flow rate ÷ 2) × (stroke time × 2 ÷ 60) ÷ ((outlet pressure − cylinder pressure in bar) × 0.99). With a stroke time of 0.5 s, a booster outlet of 10 bar and a cylinder at 8 bar, V = (841 − 600 ÷ 2) × (0.5 × 2 ÷ 60) ÷ ((10 − 8) × 0.99) ≈ 4.6 litres.

So a VBA20A booster with a VBAT10AF (10 l) air tank, which bolts directly to it, is sufficient. The compressor must supply about 1,320 l/min to the booster (2.2× more than the booster delivers).

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How a pressure booster works

1. Air from the network flows through check valves into two pressurising chambers and, at the same time, through the regulator unit and the switching valve into the drive chamber.
2. The pressure in the drive chamber, together with the pressure in one pressurising chamber, pushes on the piston. The piston compresses the air in the second pressurising chamber, and this air leaves through a check valve to the outlet.
3. At the end of the stroke, the switching valve swaps the chambers and the piston returns – now compressing the air in the first chamber. The air from the drive chamber leaves through the exhaust, which is why a silencer is fitted to the exhaust.
4. The regulator unit monitors the outlet pressure. When it reaches the set value, the piston stops, and it starts again once the machine draws air. The outlet pressure therefore pulsates slightly – the air tank evens this out.

You set the pressure with the handle: pull it up, turn it in the + direction to increase the pressure, then push it down to lock it. When you reduce the pressure, the excess air escapes under the handle. Always set the pressure from below: first reduce it below the required value, then increase it.

Installation and operation

• install the booster horizontally – the silver tie rods and covers must lie horizontally; if mounted vertically, it may not work correctly
• bolt it down with 4 bolts (M5 for the small series, M10 for the large ones) – the device vibrates during operation; if the vibration is a problem, place rubber underneath
• install a filter upstream of the booster – the AAFP basic filter and AAFM fine pre-filter catch dirt, water droplets and oil mist; the inlet strainer is only a safeguard
• the lubricator belongs downstream of the booster – oil upstream of it would accumulate in the device and cause a malfunction
• route the exhaust of each booster separately, not into a common pipe – pressure in the exhaust would disrupt operation
• choose pipework that matches the port size and blow it through before connecting
• ambient and air temperature 2 to 50 °C, without freezing
• after work, release the inlet pressure so that the device does not run unnecessarily; to release the outlet pressure quickly, install a 3-way valve downstream of the booster (the check valve in the device does not let the pressure back to the inlet)
• drain the condensate from the filter and air tank daily

Air tanks for pressure boosters

An air tank evens out pressure pulsation and covers short-term high air demand. Rule: the maximum pressure of the air tank must be at least equal to the maximum outlet pressure of the booster – the handle can be turned up to the series maximum. SMC VBAT air tanks bolt directly underneath the booster; a safety valve, a drain valve and a connection kit are included.

SMC does not make a suitable air tank for the VBA43A series (outlet up to 16 bar) – the 20 bar air tanks do not fit the VBA43A size and the 10 bar ones would not withstand the pressure. We recommend a 100 l pressure vessel for 32 bar. Use the smaller 24 l pressure vessels for 16 bar (VHR24-16, VHP24-16) only if you set the booster outlet below the opening pressure of the vessel’s safety valve.

Assembly height = air tank with the booster mounted on top, according to SMC. With a G thread, the air tank is about 6 mm longer than in the catalogue (different plugs).

Remote control: VBA22A

The VBA22A booster has no handle. The outlet pressure is set by air pressure from a small regulator connected to the P 1/8" pilot port: the outlet is twice the pilot pressure. A pilot pressure of 1 to 5 bar gives 2 to 10 bar at the outlet.

You can keep the regulator on the control panel and the booster tucked away at the machine. SMC recommends a small regulator of the AR20 series as the pilot regulator; our pressure regulator 280 G 1/8" with a range of 0.5–6 bar will do the same job.

Service kits

A booster has moving parts that wear over time. Service life does not depend on operating hours but on the number of piston strokes – the more air you draw, the sooner servicing is required. The end of service life is indicated by continuous air leakage under the handle, or by the booster exhausting every 10 to 20 seconds even though the machine is drawing no air.

We offer genuine SMC service kits for the VBA11A (KT-VBA11A-20) and VBA40A (KT-VBA40A-1) series. The kit contains piston seals, a regulator unit, check valves, seals, piston rod seals and grease. Kits for the other series are supplied on request. Maintenance should be carried out by someone experienced in pneumatics.

Special versions

SMC VBA pressure boosters are also made in versions for potentially explosive atmospheres according to the ATEX directive (category 3GD). We supply these versions on request – tell us what pressure, flow rate and connection you need.

Series specifications

What is the difference between a pressure booster and a pressure regulator?

A regulator only reduces pressure and keeps it constant. A booster increases it – an air-driven piston boosts the network pressure 2× to 4×. Its outlet pressure is set in a similar way to a regulator.

Does a pressure booster need electricity?

No. It is driven only by compressed air from the air network, so it needs no cables, heats up very little and produces no sparks.

How much air does a pressure booster consume?

It uses part of the inlet air to drive itself and releases it through the exhaust. According to SMC, the compressor must supply about 2.2× more air than the booster delivers at the outlet, and about 3.7× at a boost ratio of 4×.

Do I need an air tank for the booster?

Not always. An air tank is useful when the machine draws air intermittently or pressure pulsation is a problem. It must withstand the maximum outlet pressure of the booster.

Why does the booster occasionally exhaust even though the machine is drawing no air?

A short exhaust after a longer pause is normal. However, if it exhausts regularly every 10 to 20 seconds with no air being drawn, or air leaks under the handle, servicing will soon be needed – replace the seals with a service kit.

Is the pressure gauge included?

Only with the versions with pressure gauges and silencer – two pressure gauges and a silencer are packed in the box. The version without accessories has 1/8" gauge ports, and you can buy the pressure gauge and silencer separately.

Can I mount the booster vertically?

No. SMC specifies horizontal mounting – the tie rods and covers must lie horizontally, otherwise the device may not work correctly.

Technical data according to the catalogue of the manufacturer SMC (CAT.EUS11-96D-UK). Flow rate at an inlet and outlet pressure of 5 bar.

To reduce pressure instead and keep it constant, use air pressure regulators. You will find filters, dryers and other components in the category compressed air treatment.