Various types of vacuum generators can be used to generate the vacuum. Basically, a distincion is made between the following:

• ejectors

• vacuum pump

• vacuum blowers

Each of these generators has its specific advantages, but one principle is common to all types: high suction capacity together with high vacuum always incurs high energy consumption and thus high operating costs.

Vacuum pumps provide high vacuums at low volume flow rates, i.e. low suction capacity. They are particularly suitable where non-porous workpieces are to be handled. There are various types of pumps, namely dry-running pumps, oil-lubricated pumps and water-ring pumps. Dry-running and water-ring pumps require very little maintenance. In addition, dry-running pumps can be installed in any desired orientation, while oil-lubricated and water-ring pumps can be installed and operated only in a horizontal position.

Oil-lubricated pumps require maintenance, but are capable of generating very high vacuums of up to -0.98 bar.

Typical applications for vacuum pumps are:

• manual vacuum handling tools,

• packing machines,

• vacuum clamping devices.

In contrast to vacuum pumps, vacuum blowers generate low vacuums at a high volume flow rate, i.e. high suction capacity. They are the right choise wherever porous workpieces, through which can diffuse relatively easily, are to be handled. Vacuum bleowers, also called sidechannel compressors, operate on the "momentum principle": the kinetic energy of a cellular wheel is transferred to the air and converted into pressure.

Typical applications for vacuum blowers:

• extraction of large quantities of air in a short time

• handling of very porous workpieces such as sacks, cardboard boxes or chipboard.

Ejectors generate a high vacuum at a ralatively low vacuum flow rate. However, they differ from the pumps and blowers in that they generate the vacuum pneumatically, using the so-called "Venturi" principle. In an ejector, a stream of compressed air flows through a drive nozzle. At this "artifical bottleneck", the velocity of the air stream is far higher than in the supply line, resulting in a reduced pressure at the cone-shaped outlet. This draws the air out of the vacuum connection, generating the desired vacuum. An example of this principle is well-known to car drivers: if a window is opened slightly while the car is moving fast, air is drawn rapidly out of the car interior.

The major advantage of ejectors is that they have no moving parts and therefore require absolutely no maintenance and never wear out. Ejectors generate no heat, can be very small, and permit the implementation of very short cycle times.

Typical applications for ejectors:

• feeding parts into machines in the automobile industry,

• industrial robots in all sectors of industry,

• packing industry,

• process technology,

• clamping devices in machining centres,

• conveying of bulk goods or fluids.

You can find important formulars for calculating the suction capacity, check lists for selection of the correct vacuum generators and other information in the PDF file which you can download with the link at the bottom of this page.

You can find technical informations about ejectors and a check list for selection of the correct ejector in the PDF file which you can download with the link at the bottom of this page.