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Additional information on our range of vacuum generators

Vacuum Pumps: a range of 4 Schmalz vacuum pumps incorporating water ring pumps, vacuum centre, oil-lubricated vacuum pumps and dry running vacuum pumps that generate a very high level of vacuum. They are extremely reliable, robust, mainly used in packaging machines, manual handling systems, or for central vacuum generation in gantry-style systems.

Vacuum Blower: perfectly suited to the handling of cardboard boxes, foam materials, insulating materials, recycling materials and other extremely porous materials, it has enormous suction capacities – up to 540 m³

Compressed Air Distributor: Schmalz-developed compressed air distributors for mounting compact ejectors in blocks with a single compressed air inlet.

Basic & Compact Ejectors: This range consists of multi-stage ejectors, inline ejectors and compact ejectors, as well as a range of ‘other ejectors’. The latter is a specialised range of ejectors for various applications with short cycle times.

Vacuum generator types

A vacuum, in vacuum generators, is created either pneumatically or electrically. Pneumatic vacuum generators implement short cycle times and can be integrated directly into the system due to their compact and lightweight design.

Electrical vacuum generators are used in applications when compressed air is not available, or when very high suction capacities are required.

The nominal suction rate of all vacuum generators is given in l/min or m3/h. The values are based on an ambient pressure of 1,013 mbar (sea level) and an ambient temperature of 20° C.

The maximum suction rate, therefore, indicates the volume flow that the vacuum generator evacuates from the environment – which is known as free flow.

The operating principles of vacuum generation

Vacuum generators provide the required vacuum, which is generated either pneumatically (ejectors) or electrically (pumps, blowers). Pneumatic vacuum generators implement short cycle times and can be integrated directly into the system due to their compact and lightweight design.

Ejectors on the other hand offer intelligent functions for energy and process control. Electrical vacuum generators are used in applications when compressed air is not available or if very high suction capacities are required.

  • For the Venturi Principle compressed air is introduced into the ejector (A) Due to the reduced cross-section of the motive nozzle (also called the Venturi nozzle) (B), the compressed air is accelerated. The dynamic pressure increases, while the static air pressure simultaneously decreases. Once it has passed the motive nozzle, the accelerated air expands and a vacuum is generated. Air is sucked through the vacuum connection(D) into the ejector, and finally the compressed air escapes from the ejector through the silencer (C) together with the sucked-in air. This vacuum technology can be used for universal vacuum systems

  • Bernoulli's Principle is a pneumatic operation with integrated vacuum generation whereby compressed air escapes through holes in the suction cup and is greatly accelerated. Due to the increase in speed, the static pressure falls and a vacuum is produced (A). This is known as the "Bernoulli Equation". The Bernoulli principle is used for universal vacuum generator applications in vacuum systems.
  • The accelerated air escapes to the side (B) and an ‘air cushion’ is produced between the floating suction pad and workpiece. Leakage is compensated for through a high flow rate, which means that even porous workpieces can be handled and separated. The Bernoulli effect ensures that the workpieces are handled with minimal contact. Floating suction cups are an example of those that function according to Bernoulli's principle. This principle is ideal for use with the handling of very thin, highly sensitive or extremely permeable workpieces.

  • The Coanda Principle is also a pneumatic operation with integrated vacuum generation, but the difference here is that compressed air is guided through an annular gap which accelerates it. The increase in the flow rate speed results in the "Coanda effect", in which the escaping air follows a convex surface. The air flowing along the surface produces suction in the ambient air.

Advantages of the three operating systems

Venturi Principle

  • Suitable for very high accelerations
  • Vacuum grippers can be controlled individually
  • Ejectors in different designs for centralised and decentralised vacuum generation
  • Various power classes

Bernoulli Principle

  • Low-contact, gentle handling of thin and sensitive workpieces
  • Safe separation of thin and porous workpieces

Coanda Principle

  • High suction rate and low air consumption
  • Large contact surface & narrowly positioned vacuum openings prevent the workpiece from being sucked in / damaged
  • Suction areas can also be partly engaged

The range of vacuum generators is only one of more than 3 500 vacuum components from the Schmalz range of components for vacuum handling and gripping systems.

For more information, contact Tectra Automation on +27 11 971 9400.