Have you ever wondered how vacuum pumps work? It’s all part of a process. Here’s what it looks like:

LRVPs are rotary displacement pumps which operate in an essentially isothermal process. An impeller is mounted eccentrically to the axis of a casing, and the liquid ring, which consists of service liquid, circulates concentrically inside the axis of the casing. The seal liquid leaves and re-enters the impeller buckets in a piston-like motion. Gas is then aspirated into the liquid ring via the suction port. The void in the centre holds gas drawn in through the pump’s inlet port. As the gas travels around the pocket of air in the centre, it is compressed. This compressed air is then fed back out through the discharge port.

LRVPs can achieve a maximum vacuum of 95% barometric pressure, dependent on the type of sealant liquid used.

When operating at altitudes higher than sea level, atmospheric pressure decreases, meaning the higher you are, the less vacuum you can achieve. It’s important to take note of this as it affects vacuum pump performance. While flow is unaffected, operation at higher altitudes reduces the achievable capacity and maximum vacuum levels.

The liquid ring not only acts as a seal; it also absorbs the heat of compression, friction, and condensation. In principle, any liquid can be used, but water, oil, glycol, or other liquids that will not vaporise at process conditions are most commonly used.

The main advantages of liquid ring vacuum pumps are the following:

• Simpler design than most other vacuum pumps; only uses a rotation system.
• May be made of any casting metal.
• Small noise and vibration.
• Very little increase in the discharge gas temperature.
• Can handle condensables.

• Suction capacities from 20 to 54,000 m³/hr
• Operating pressure down to 33 mbar
• Wet and dry gases
• High tolerance to liquid carryover
• Low water usage
• Low noise levels

Applications

• Condenser evacuation
• Pulp and Paper
• Filtration
• Chemical and Petrochemical applications
• Power (FGB)
• Vacuum forming
• Pharmaceutical
• Mining
• Steel degassing
• Biofuels