Introduction
In industrial applications, the primary purpose of vacuum pumps is to create and maintain a controlled low pressure or vacuum environment.
This reduction in pressure – commonly referred to as ‘vacuum’ – is essential to enable, optimise and control a wide range of processes and chemical reactions that are either inefficient or impossible at atmospheric pressure. Liquid Ring Vacuum Pumps are particularly useful in achieving these conditions.
Many chemical reactions and processes require a vacuum environment to take place effectively.
By reducing the pressure within a reaction chamber, vacuum pumps can lower the boiling point of liquids, improve mass transfer and remove gaseous by-products that might otherwise inhibit the reaction.
In distillation processes, for example, a vacuum is used to separate components at lower temperatures, protecting heat-sensitive materials and improving energy efficiency.
Liquid ring vacuum pump
Courtesy of the Travaini pumpe.
Typical Range of Application
- Pressure range
Liquid ring vacuum pumps typically operate in the medium vacuum range. They can achieve vacuum levels from approximately 33 mbar (abs) to atmospheric pressure. This makes them suitable for a wide range of applications where deep vacuum is not required. - Volume range
The volume capacity (or flow rate) of liquid ring vacuum pumps can vary significantly depending on the size and design of the pump. Smaller pumps can handle a few cubic metres per hour, while larger industrial units can handle several thousand cubic metres per hour.
When to Use Liquid Ring Vacuum Pumps
Handling Moist or Condensable Vapours
Liquid ring vacuum pumps are particularly effective in processes that involve handling large volumes of gases with high moisture content or condensable vapours.
These pumps are good in applications such as condensation, evaporation, and degassing, commonly found in industries like chemical processing, pharmaceuticals, food production, and power generation.
Their ability to tolerate moisture without damage makes them suitable in these moisture-rich environments.
Tolerance for Contaminants
One of the key strengths of liquid ring vacuum pumps is their resilience in handling gas streams containing dust, particulate matter, or minor contaminants.
Unlike more sensitive vacuum pump technologies, liquid ring pumps can operate effectively in environments with dirty or unrefined gases, making them ideal for processes such as wastewater treatment, pulp and paper manufacturing, and mining operations, where contaminant-laden gases are a common challenge.
Isothermal Compression for Heat-Sensitive Processes
The compression process within a liquid ring vacuum pump is nearly isothermal, meaning that minimal heat is generated during operation.
This feature is beneficial when working with heat-sensitive materials, ensuring the integrity of the processed substances while maintaining energy efficiency.
Simple and Robust Design for Low Maintenance
Liquid ring vacuum pumps are engineered with a simple and durable design, featuring fewer moving parts than other vacuum technologies. This simplicity contributes to their lower maintenance requirements and long service life. The robust construction allows these pumps to withstand harsh conditions and reduces the likelihood of damage from contaminants or operational stress, making them highly reliable in demanding industrial applications.
Versatility in Sealing Liquids
A key advantage of liquid ring vacuum pumps is the flexibility to use various sealing liquids, enabling customization based on specific process requirements. Water is the most common sealing liquid due to its availability and low cost, but other liquids like oils or specialised chemicals can be used when chemical compatibility or higher temperature resistance is necessary. This versatility ensures that liquid ring pumps can be adapted to a wide range of industrial environments.
When Liquid Ring Vacuum Pumps Are Not Suitable
Deep Vacuum Applications
Liquid ring vacuum pumps are not ideal for processes that require deep vacuum levels, typically below 33 mbar. For high-vacuum applications, alternative technologies such as diffusion pumps or turbomolecular pumps are more appropriate due to their ability to achieve much lower pressure levels.
Contamination-Sensitive Processes
Although liquid ring pumps can tolerate some contamination in the gas stream, they are not suited for applications where even minimal contamination from the sealing liquid is unacceptable. In such scenarios—common in food, pharmaceuticals, or semiconductor manufacturing—dry vacuum pumps, which operate without sealing fluids, would be the preferred choice.
Use of Expensive or Hazardous Sealing Liquids
If a process demands the use of an expensive or hazardous sealing liquid, the operational costs and potential safety risks associated with the liquid ring pump might outweigh its benefits. Handling such liquids requires careful consideration of both the financial and safety implications, which could make dry vacuum technologies more practical.
Applications Requiring Oil-Free Vacuum
Liquid ring pumps inherently require a sealing liquid to function, which disqualifies them from being considered oil-free. In environments where oil-free operation is a strict requirement—such as in medical equipment manufacturing or semiconductor fabrication—dry vacuum pumps are a better solution, as they eliminate the risk of contamination from liquids.
Processes Sensitive to Pulsations
Liquid ring vacuum pumps can introduce pulsations in the vacuum flow, which may disrupt processes sensitive to fluctuations in pressure. For applications where a steady, pulsation-free vacuum is critical, other types of vacuum pumps, such as rotary vane or scroll pumps, may provide smoother and more consistent vacuum flow.
SPS Pumps, The Experts You Need
SPS Pumps provides reliable and efficient liquid ring vacuum pumps for industrial use.
We have years of experience in providing vacuum solutions.
We understand the challenges faced by different industries and are committed to delivering long-lasting pumps.
Our experts are here to help with everything from choosing and installing to maintaining and supplying spare parts.
Call us now at +32 2 657 23 53 or email at info@sps-pumps.com.
