Venturi vacuum generators
vs. mechanical vacuum pumps
Expert recommendations for choosing your vacuum pumps in automation:
What is the difference between ejectors and mechanical vacuum pumps?
Electromechanical vacuum pumps and Venturi ejectors serve similar purposes but operate differently, each with their own pros and cons for pick-and-place applications.
Key considerations include initial investment, ongoing costs, and maintenance.
Whilst both vacuum sources serve similar purposes, this article by our Becker market experts offers recommendations to determine the most-suited vacuum solution that best suits your unique needs, market and application.
What is a 'Venturi vacuum ejector' and what is the principle of action?
The Venturi effect is the reduction in fluid pressure that results when a fluid flows through a constricted section of a pipe. In the case of a vacuum ejector, compressed air is passed through a nozzle, creating a high-velocity jet.
Ejectors differ from positive displacement and turbo dynamic pumps, which utilise different operating principles to create vacuum or low-pressure in a chamber. Covering a wide range of operating principles, Becker offers various vacuum pumps, including rotary vane, screw, claw, radial, and regenerative blowers for different applications.
Disadvantages of an ejector?
While compact and relatively inexpensive, ejectors often can't achieve the deep vacuum levels that some vacuum pumps can, making them less suitable for applications requiring low pressures.
8 factors for consideration:
1. Costs - Acquisition, Energy Requirements and Maintenance
An ejector vacuum system may seem to be a somewhat cheaper solution compared to an electromechanical vacuum pump in terms of purchase in the first step. However, considering the entire system; follow-up costs for an air compressor, regular maintenance, and the energy required for operation - represent a significant expense.
For example:
The technical comparison in the above graphic shows that at a vacuum level of approx. -600mbar (approx. -18inHg), which is typical for pick and place applications. A single Becker VT4.16 60 Hz can replace a combination of 3 ejectors from a common manufacturer.
This typical combination of ejectors requires 5.69 Nl/s of compressed air at 6 bar, which corresponds to an electrical energy consumption of 2.28 kW. With the same volume flow, a VT4.16 has a power consumption of 0.75kW at 60Hz. As a result, the electric Becker vacuum pump is about three times as efficient in continuous operation.
With rising energy prices, this usage is a significant part of total operating costs for manufacturers. For efficient and economical vacuum generation, electromechanical vacuum pumps are recommended.
2. Moving Parts
The Venturi ejector system is oil-free and has no moving parts, but its compressor may release oil residues via exhaust air. This is an obstacle for many industrial applications.
In the packaging, print and paper sectors, for example, oil residues or similar lubricating operating fluids are largely inadmissible, making an oil-free vacuum pump a great solution.
3. Air Compressor Capacity
If the existing compressor system is almost exhausted in terms of capacity, the purchase of an additional compressor (plus accessories) is often indispensable for the smooth operation of an ejector system.
Such an investment should be taken into account in cost analysis.
4. Heat dissipation
Kindly note that the heat generation of a compressor in continuous operation is much higher than that of an electromechanical vacuum pump.
In food packaging and processing where temperature levels are a key concern, centralised systems are an answer to remove additional, unwanted heat from the workspace.
5. Precision of vacuum
Generating a precise, stable vacuum is challenging with ejectors. Electromechanical vacuum pumps, however, can be finely adjusted to maintain the required vacuum throughout all process steps - with the addition of a variable speed drive, otherwise known as a frequency inverter.
Therefore, for critical vacuum precision, electromechanical vacuum pumps are the right choice.
6. Noise Level - occupational health and safety
Noise protection is crucial in selecting a vacuum system. During the bleeding process, ejector systems are up to 16 times noisier than electromechanical pumps.
Placing pumps in a separate room or using Becker's optional soundproofing hoods can further reduce noise.
7. Piping Requirements
An ejector vacuum system requires an extensive, costly piping system that can be prone to maintenance issues - representing weak points in the system. In contrast, an electromechanical vacuum pump is set up directly at the point of use.
The stationary placement thus eliminates the need for expensive pipelines.
8. Compressor Failure
Despite regular maintenance and servicing of the compressor, a failure may occur. As a result, the entire ejector system comes to a standstill. This inevitably results in costly production downtime and repair costs.
The failure of an electromechanical vacuum pump can be bridged quickly, cost-effectively and easily with a replacement or reserve pump.
Examples of Electromechanical Vacuum Pumps in the Pick and Place applications:
- Oil-free rotary vane vacuum pumps (VT, VX and KVT series)
- Side channel vacuum pumps (SV series)
- Claw vacuum pumps (BCV series)
Other named benefits that these pumps enjoy are:
- Adjustable vacuum levels
- Suitable for long cycle times
- Compact design
- Low pulsation and vibration
- Low maintenance
- Suitable for pressure and vacuum
The right solution for you:
The choice between an electromechanical vacuum pump and a vacuum ejector depends on the application’s specific needs, such as vacuum levels, flow rates, and energy efficiency.
Your local Becker expert will be happy to provide personalised advice based on your requirements, concerns and unique application.
Arrange a free, non-binding consultation and download data sheets and an overview flyer from our website.
EJECTORVENTURI EFFECTMECHANICAL VACUUM PUMPPICK AND PLACEAUTOMATIONOPERATING PRINCIPLEVACUUM PUMPROTARY VANECLAW
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