Oilless Rotary Scroll Pumps Ideal For Clean-Room Applications
Air Squared has developed a new line of high-vacuum rotary scroll pumps for use in a range of process control applications. The units are said to provide vacuum to 0.5 torr (less than 10 torr is considered high vacuum) and offer projected time between maintenance of 10,000 hr. The oilless mechanics make these pumps ideal for clean-room applications.
Two models are available. Model LSL-200B measures 10.2 x 6.9 x 6.5 in. and requires 350 watts shaft power. Model LSL-400 B measures 10.4 x 7.5 x 6.9 in. and requires 500 watts. Both use ac motors as standard, with speeds of 1750 rpm. Noise levels are rated as low as 49 dbA.
Both models can be used in compressor mode, producing 25 liters/min at 25 psig and 80 liters/min at 25 psig, respectively.
The core of the pump consists of two, identical meshed rolls (involute spirals), each attached on its 'out' side to a flat base. One scroll is fixed, the other connected to an electrically driven eccentric. Indexed 180 deg to each other so their spirals mesh, the scrolls fit together to form two halves of a chamber. The indexing creates crescent-shaped pockets between the involutes of the meshed scrolls and the base plates.
Air entering the pump through a port at the center of the fixed roll gets trapped in the pockets. As the moving scroll orbits the fixed one, the pockets follow the spiral inward, getting progressively smaller and compressing the air. Finally, the air is exhausted through an outlet at the center of the scrolls.
Compared to reciprocating units, scroll compressors are said to provide smooth, pulse-free operation without noisy valves and vibration. Rotary motion allows dynamic balancing, which reportedly provides nearly vibration-free operation. And with only one moving part, scroll designs are claimed to be more reliable and durable.
Air Squared, Inc.