Quick! Can you name the oldest type of low-pressure blower? If you guessed the lobe blower, you’d be correct. Lobe blowers, also referred to as rotary lobe blowers or Roots blowers, are a type of positive displacement blower originally invented in the 1800s by the Roots brothers. Even over a century and a half later, this type of low-pressure technology still exists and remains popular in a variety of industries and processes.
Lobe blowers consist of two rotors spinning in opposite directions. The blower sucks in air, and the lobes spin the air around before pushing the air out. They produce a high volume of air but at low pressure. Although rotary lobe blowers require minimal maintenance, they let some air escape. Lobe technology hasn’t been updated too terribly much since it was originally invented, with the main advancements having been focused on noise reduction. They are ideal in industrial areas such as wastewater treatment, vacuum processing and conveying, pneumatic conveying, or in chemical applications.
Compared to screw blowers, the positive displacement blower technology is less efficient; on the flip side, they do require less initial investment in terms of cost. These blowers are ideal for applications and processes that require pressures of around 250 to 450 millibars (3.6 to 6.5psig) in rather short periods of use – but that must be reliably supplied with the correct amount of air. The simple and robust design of these blowers has also proven itself in harsh environmental conditions. These blowers tend to cope very well at great heights and with high ambient temperatures, so that companies usually don’t need to dedicate a separate room for these machines.
Note: rotary lobe technology is not an economical solution for high volume flows. They also have relatively high noise levels and work with a belt drive, which can wear out over time. It then becomes less efficient and must be replaced.
So, if both the air requirement and operating pressures are very low (below 6 psig), a lobe blower might be an ideal choice. However, as with any equipment selection, the chosen solution should be individually tailored to the respective process requirements and demands. Talking to a trusted low-pressure air provider about technology options is the best place to start.
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