The scroll vacuum pump evolved from the scroll compressor. Its structural principle was first invented by the French engineer Cruex in 1905, but due to technological limitations at the time, it was not applied to vacuum technology until around the 1980s. The scroll vacuum pump features a simple structure, few components, small clearances, low leakage rates, and a high compression ratio. It provides stable pumping speeds across a wide pressure range. The continuous volume change within its compression chamber results in minimal fluctuations in driving torque, power consumption, vibration, and noise. Additionally, it requires no cooling water or lubricating oil, offers simple maintenance, and high reliability.
Generally, the pumping speed of scroll vacuum pumps does not exceed 1000 L/min. Scroll pumps with pumping speeds greater than 4 L/s typically use a dual-side scroll structure, while those below 4 L/s often employ a single-side scroll structure. Their ultimate vacuum is approximately 1 Pa.
1. Working Principle
The working chamber of a scroll vacuum pump consists of a pair of conjugate scroll disk pairs meshed together. A scroll disk is a spiral-shaped component with one or more involute spiral grooves on its surface. A stationary scroll disk and an orbiting scroll disk are assembled together in an interlaced configuration, with an anti-rotation mechanism maintaining a 180° phase difference between them.
The stationary and orbiting scroll disks form several crescent-shaped sealed chambers through contact at multiple points (visible as lines in cross-section). Driven by a crankshaft, the orbiting scroll disk rotates around the center of the stationary scroll disk. The movement of contact points along the scroll surface enables gas suction, compression, and exhaust.
With each full rotation of the crankshaft (powered by the motor), new crescent-shaped chambers are created, completing the suction, compression, and exhaust cycles. This process achieves containment and forced transport of the pumped gas.
2. Structural Features
The scroll vacuum pump has a simple structure, primarily comprising five components:
① Stationary and orbiting scroll pair and base
② Crankshaft
③ Seals
④ Anti-rotation mechanism
⑤ Motor
The only major moving part is the orbiting scroll disk. Power transmission is straightforward, and its small motion radius relative to its size ensures a compact design, smooth operation, minimal wear, and low power consumption. The dynamic seal between the motor shaft and the pump chamber, achieved by seals, prevents oil vapor contamination. These seals typically last 1–3 years and require replacement after failure.
Applications
Scroll vacuum pumps have relatively low pumping speeds and are unsuitable for handling toxic, flammable, explosive, or corrosive gases, as well as media like solvents, powders, or pharmaceuticals. Currently, they are widely used in analytical instruments, semiconductor chip production lines, LCD display production lines, and scientific research equipment. Due to their oil-free operation and ability to start under atmospheric pressure, they are often employed as foreline pumps for molecular pumps and small cryogenic pumps to achieve clean, oil-free high-vacuum environments.
Post time: May-27-2025