Venturi vacuum generators
vs. mechanical vacuum pumps
Expert recommendations for choosing your vacuum pumps in automated handling:
There is no benefit of a vacuum that isn’t right for your business. Therefore, it is important to compare your options carefully before committing to an investment.
Electromechanical vacuum pumps and Venturi vacuum ejectors serve different purposes and have distinct advantages and disadvantages in pick-and-place applications. Sourcing a vacuum system should never be done on a whim. The investment not only has an initial purchase cost, but also an ongoing financial impact on operations and maintenance.
But how do they compare in the long run? We are here to help.
When choosing your vacuum source, you’ll find manufacturers of both Venturi vacuum systems and motor-driven (mechanical) vacuum pumps.
Venturi generator manufacturers include companies such as Air-Vac Engineering, Festo, VMECA, Gimatic, Fipa, and PIAB to familiarise you with your options. While Becker, Busch, Travianni, G-D, Dekker, and Gast are examples of mechanical vacuum pump manufacturers. Venturi vacuum sources are often favoured for their low initial costs and ease of integration.
What is a 'Venturi vacuum ejector' and what is the principle?
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.
Becker manufactures positive displacement and turbo dynamic pumps. Covering a wide range of operating principles, our portfolio includes rotary vane, screw, claw, and radial vacuum pumps, and regenerative blowers configured for vacuum applications.
With a little help from Becker expert, Dario, we hope that you can weigh up the most suitable solution to your unique concerns and application.
Factors to Consider Before Choosing a Venturi Generator or Mechanical Pump
Here are eight factors to compare before purchasing a vacuum system:
1. Energy Costs
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, if you look at the system as a whole, the follow-up costs for an air compressor, the regular maintenance of the compressor and accessories / lines and the actual energy requirement for the operation of the system represent a not inconsiderable cost factor.
On average, the energy requirement of an ejector vacuum system is about three times as high as that of an operation with a stand-alone Becker vacuum pump.
For example:
The technical comparison in the following graphic shows that at a vacuum level of approx. -600mbar (approx. -18inHg), which is typical for pick and place applications, a Becker VT4.16 60 Hz can replace a combination of 3x 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 VX4.16 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.
Ejectors, even if they are used in multiple stages, usually have a "softer" air supply curve compared to positive displacement pumps. It is, therefore, important to consider the performance in the working point. Concluding, it is not the free flow of the ejectors that should be compared with that of a mechanical pump, but always the volume flow at the operating point.
With energy prices rising year-on-year, this part of the operating costs is a significant part of the total operating costs. For efficient, environmentally friendly and economical vacuum generation in permanent demand, we recommend electromechanical vacuum pumps from Becker.
2. Moving Parts
While the actual Venturi ejector system has no moving parts and is oil-free, the compressor used could contain oil residues that are released with the ejector's exhaust air. This is an obstacle for many industrial applications.
In the packaging industry, for example, oil residues or similar lubricating operating fluids are largely inadmissible, so Becker's oil-free vacuum pumps are the perfect 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 the 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.
5. Precision of vacuum
The generation of a precise and permanently stable vacuum level is often a challenge when ejectors are used. In contrast to ejector systems, electromechanical vacuum pumps can be adjusted extremely precisely according to the specific requirements and manage to maintain the required vacuum for all process steps.
Therefore, for applications where vacuum precision is critical, the use of electromechanical vacuum pumps is the right choice
6. Noise Level - occupational health and safety
A not insignificant factor in choosing the right vacuum system is the consideration of noise protection (occupational safety).
During the bleeding process, an ejector system generates up to 16 times the noise level compared to an electromechanical vacuum pump. Another way to minimise noise pollution is to place the pumps in a separate pump room.
For the additional reduction of the noise level, Becker has various vacuum pumps with an optional soundproofing hood in its range.
7. Piping Requirements
The compressed air supply for an ejector vacuum system by means of a compressor is largely linked to an extensive piping system. In addition to the expensive installation, maintenance also has an impact. Furthermore, pipelines and their connections also represent a weak point in the system.
An electromechanical vacuum pump, on the other hand, is set up directly or immediately at the point of use. The stationary placement thus eliminates the need for pipelines.
Practical test: At the operating point, the compressed air consumption is about three times as high as the vacuum flow of the ejector - in continuous operation, this means three times the operating costs; another considerable expense to take the burden of.
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 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 Becker Electromechanical Vacuum Pumps
in the Pick and Place industry:
- 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
- Continuous operation - suitable for long cycle times
- Compact design
- Lower-noise levels
- Extremely precise control
- Good volume flow - pump size ratio
- Low pulsation and vibration
- Low maintenance
- Suitable for pressure and vacuum
- Flow rates of up to 600 1/min - with larger pumps also available in our range
- Vacuum down to -900 mbar
The right solution for you:
When choosing the right vacuum pump to replace an ejector always consider the operating point. Comparing the open flow will result in over-dimensioning of the vacuum pump and reduce possible savings.
It is important to note that the choice between an electromechanical vacuum pump and a vacuum ejector depends on the unique requirements of the application, including desired vacuum levels, flow rates, energy efficiency, and operational considerations.
Your local Becker expert will be happy to advise and support you in choosing the best electromechanical vacuum pump solution for your requirements. Arrange your free non-binding consultation direct.
For additional information, our data sheets are available for direct download from our website.
For an overview, flyer is also available for download below.
