Four ways to make your vacuum system more efficient

With high energy prices, efficiency has become a top priority for production sites using vacuum systems for product handling. Fortunately, based on decades of experience and know-how, SMC can offer four simple ways to reduce the energy consumption of your vacuum system. By using less energy in picking and moving, you make a direct contribution to reducing CO2 emissions.

The latest energy-saving vacuum technologies can make a substantial difference for applications involving vacuum, whether in packaging, metalworking, life science or any other sector. If you follow the four steps below, you will significantly improve the efficiency of your vacuum system. 

It is possible to generate vacuum centrally using a vacuum pump or vacuum ejectors. SMC's extensive range of vacuum ejectors - from very compact inline ejectors to efficient multistage ejectors with powerful silencers - are suitable for vacuum flows of up to 600 Nl/min, meeting the requirements of virtually any industrial application. Each type of ejector has its specific parameters, which are interdependent: standard operating pressure (the amount of compressed air required to achieve the highest possible vacuum pressure), maximum suction flow rate (amount of air taken in by the ejector), maximum vacuum pressure (maximum value of vacuum pressure generated by the ejector) and compressed air consumption (the amount of compressed air consumed by the ejector when operating at the standard supply pressure).

4 bar: the maximum supply pressure for SMC ejectors

Ask yourself whether you really need the maximum vacuum pressure to handle your workpiece. After all, the level of vacuum pressure is directly related to your compressed air consumption and costs. For example, if you operate the ZL112A ejector (with valves) with a main line pressure of 0.5 MPa (5 bar), your compressed air consumption will be about 78 l/min (4,680 l/hour) to achieve a maximum vacuum pressure of -84 kPa. By running the ejector at a reduced 0.35 MPa (the standard supply pressure for this type of ejector), you can reduce compressed air consumption to 57 l/min (3,420 l/hour) and still achieve the same maximum vacuum pressure (-84 kPa). A significant energy savings from 27%.

Many manufacturers still work with the standard operating pressure of 7 bar, while an optimal vacuum system takes place at an average of 4 bar. A reduction from 7 to 4 bar is beneficial for your operating results and the future of our planet. At the same time, it does not affect the effectiveness of your operations. Returning to the example, if you can safely pick up the workpiece with a maximum vacuum pressure of -65 kPa, then you can reduce the supply pressure even further to 0.25 MPa (2.5 bar). This will reduce your compressed air consumption to 45 l/min (2,700 l/hour), yielding impressive 43% energy savings. 

Use vacuum suction cup with larger diameter, no higher supply pressure

Some engineers make the mistake of increasing the feed pressure if they want to achieve higher holding force. However, this leads to higher energy consumption and costs. In fact, it is directly proportional: doubling the vacuum pressure will double your holding force as well as energy costs. Instead, it may be possible to increase the diameter of your vacuum suction cups in certain applications. When doubling the diameter of the suction cup, you quadruple the holding force, while your energy costs remain the same because there is no increase in supply pressure. The price difference between a 20 mm and 40 mm diameter vacuum suction cup is usually less than 5 euros.

Vacuum ejectors with energy-saving function

Some vacuum ejectors are equipped with a vacuum pressure switch with energy-saving function that can reduce energy consumption up to 93%. How they work. First, you determine the pressure range within which you can safely hold the workpiece, for example, from -65 to -55 kPa. The integration of a pressure switch with energy-saving function serves to shut off the air supply when the desired vacuum level is reached. Vacuum is generated again only when the pressure falls below the lower range, in this case -55 kPa. Consider a vacuum system with a conventional ejector running 450 cycles per hour, 10 hours per day, for 250 days per year. Such a system consumes about 9,350 m3 of compressed air per year. However, using a vacuum ejector with an energy-saving function will reduce compressed air consumption to only 638 m3 per year, yielding the aforementioned 93% savings. The potential savings are higher in long-cycle applications.

Smart management

To maximize the use of an energy-efficient vacuum system, SMC recommends using "smart" ejector systems. An ejector baseplate that communicates serially does not require separate input/output units to operate and avoids complex electrical wiring of valves and sensors. Serial communication can be connected directly to the PLC. Through the PLC, it is possible to set and monitor pressure values, vacuum or release function, energy saving function and valve protection function. This concept leads to better control of your application, more valuable data and on-board product diagnostics.

Technical Support

If you've ever dealt with a vacuum system, you know that vacuum can be unpredictable because the interaction and behavior between workpiece and vacuum suction cup varies depending on the application. The only real way to be sure of the results is to consult an expert knowledge partner such as SMC, which can perform tests at its own Technology Lab in Eindhoven, Netherlands. 

The SMC Technology Lab in Eindhoven

Vacuum is often a matter of trial and error regarding pressure, flow rate, suction cup size, number of suction cups and more, especially when it comes to workpieces made of special materials. So why not leave it to the experts to figure it out? With energy costs soaring worldwide, few companies can afford to ignore the energy-saving potential of a properly specified and configured vacuum handling system. It's time to get a grip on efficiency.