Pressure boosters

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What can be done if the application requires a higher pressure than the compressor can supply?

Pressure amplifiers, so-called pressure boosters, are used for this
purpose. 
 


Application parameters

The use of a pressure booster is particularly recommended when the pressure in a system needs to be selectively increased. A system or sections of it do not have to be supplied with excessively high pressure, as this would lead to substantially higher operating costs.
Pressure boosters can also be used for mobile devices, i.e. in mobile pneumatics. An initial low pressure can be generated using relatively small compressors, and then reinforced with the aid of the booster.
However, pressure boosters are not a replacement for compressors!


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Pressure boosters with integrated regulators


Description

The Festo pressure booster requires no other source of compressed air than compressed air.
Pressure boosters are classified as twin-piston pressure boosters and are intended solely for compressing air. The basic variant of the booster consists merely of a double piston system and a directional control valve for continuous operation. With this design, the input pressure is automatically doubled; it is not possible to adjust the pressure to a lower value.
Pressure boosters which also have a pressure regulator can boost the pressure to less than double the set value. In this case the pressure regulator reduces the pressure in the outside chambers.
This is important for the pressure amplification achieved. Depending on the function, however, the pressure cannot be boosted to more than twice a particular value.
Pressure boosters cannot vent themselves, i.e. the air can only flow in one direction. This means that pressure boosters cannot necessarily be used in a working line between valves and cylinders.

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Function


Step 1

The operating pressure directly pressurizes chambers 1 and 4 via two non-return valves. Chamber 3 is also pressurized via the directional control valve and chamber 2 is exhausted. Because pressure is now acting on two piston surfaces simultaneously, more than a single piston force is available. Depending on the adjustment of the pressure regulator, a maximum total of double the piston force is available.

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Step 2

The pistons move to the left and compress the volume in chamber 1 (coloured red).

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Step 3

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The compressed volume then exits the pressure booster outlet via a non-return valve. As soon as the piston rod reaches the end position, the directional control valve is switched with the aid of a recess on the piston rod. This recess opens up a connection between chamber 1 and the pilot line of the directional control valve. After switching, the same processes begin on the opposite side of the pressure booster, and the compression is continuously applied. As soon as the secondary pressure has been reached, the supply is stopped automatically.

It is possible to connect the storage reservoir to the output of the pressure booster in order to even out the pulsation of the booster. If used in this way, a reservoir can be connected in parallel with the pressure booster's operating pressure. The reservoir can then be filled with the supply pressure and the pressure booster merely has to make up the difference between the supply and output pressures. When using non-stainless reservoirs, a filter should be installed between the booster and the reservoir so that any rust particles generated cannot get into the booster.
By pressurizing alternate sides of the booster, an internal air consumption is generated in the pressure booster. This is dependent on the selected amplification gain.