The following is an excerpt from my recent article Solving the Top Challenges of Industrial Vacuum for Blower & Vacuum Best Practices. The full version can be read online or in the September issue of the magazine.
Industrial vacuum can be defined as vacuum used to perform a task in industrial processes, operating anywhere from atmospheric pressure to 1 torr. Traditionally, the most common technologies included liquid ring and rotary vane vacuum pumps. But as with any industry, there was room for improvement… otherwise, we’d still be driving Model A Fords and talking on corded telephones. Luckily in recent years, the industrial vacuum market has started making significant advancements in technology and efficiency.
If we step back into the not-so-distant past, virtually all industrial vacuum pumps were fixed speed machines that ran at one, consistent speed. The constant speed of these machines did not address varied processes with fluctuating demands, which then caused large inefficiencies between the vacuum pump and the process.
Variable Speed Drive
With the development of Variable Speed Drive (VSD) technology built into industrial vacuum pumps, we can mitigate a lot of energy waste by controlling the motor speed to match the process demand.
While energy savings with VSD industrial vacuum pumps is the primary focal point, there are other benefits to consider when comparing VSD pumps to their traditional fixed speed counterparts. Let’s take a look at some of the benefits.
VSD vs. Fixed Speed
There have been attempts in the past at adding VSD to industrial vacuum technology, but the benefits were negligible due to the nature of some of these technologies. Turn down capability, or the amount of available functional speed reduction, can be limited with certain types of pumps.
Technology such as the oil-sealed rotary screw benefits the most when coupled with VSD technology. This technology will give a wide range of turn down capability, allowing it to operate anywhere from full speed down to around 10-percent speed. In contrast, other compression technologies are at a disadvantage when it comes to varying pump speed. For example, if you look at the operating principle of a liquid ring vacuum pump, the actual compression occurs when a volume of gas is trapped within a ring of liquid, similar to a washing machine’s spin cycle. This ring of liquid is created through centrifugal force, and as the pump’s motor slows, the centrifugal force is lost and there is no compression. The same goes for rotary vane technology where sliding vanes create compression but also rely on centrifugal force. With the limited ability to slow these technologies, VSD becomes less of a benefit in energy savings.
You can read the full article on industrial vacuum pumps online or in the September issue of Blower & Vacuum Best Practices. For more articles like this, make sure you subscribe to our blog.