Liquid Ring Vacuum Pumps – Operation, Characteristics and Applications
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Liquid Ring Vacuum Pumps – Operation, Characteristics and Applications

There are manufacturing companies today that uses technologies, which is equipped or installed with various types of vacuum pumps like the liquid ring because this helps in the production and processing of particular products. Those who are working in the industrial and engineering teams will have to deal with this, especially when operation and maintenance is concerned. However, we are not all knowledgeable when it comes to this pumping system, so we need to know how it functions and works in the field of engineering.

Basically, a vacuum pump is specifically designed to remove gas particles from a sealed container or volume and leaving only a partial amount of space behind. In fact, Otto von Guericke invented this very first machine in 1650 and up to this time, his concept is still being used as a basis for modern and a more advanced method. That’s why we have numerous mechanisms in our generation today and this has led to the development of better engineering and industrial techniques.

When it comes to a liquid ring vacuum pump, the mechanism is applied using certain categorized techniques. One is the positive displacement which is a mechanism that used to expand or seal off cavity, allow air to flow or exhaust at a low speed. Next is the momentum or molecular transfer pump which makes use of fluids at a high speed to remove gas molecules. While the entrapment pump will capture these molecules.

What Is A Liquid Ring Vacuum Pump?

This is a mechanism with rotors that uses positive displacement technique and also used as a compressor for gas. It functions just like a rotary vane, but rotors are designed with vanes that are actually its integral part. This makes it different from other types.

By the way, the integral part or vanes come with liquid rotating rings which helps in forming the seal for the compression chamber. The friction is quite low since the only part that moves is the rotor and needs an induction motor for power.

It is technologically designed to achieve optimal and reliable performance in the industrial and engineering environment. For this reason, it has to be robust in terms of engineered solutions and economical to meet the customer’s specific needs.

How it Works

Various applications use this type of vacuum pump, especially in the industrial manufacturing field. These applications include chemicals, electrical power, mining, food processing, environmental, oil, gas, textiles, marine, pharmaceutical, pulp, and paper to name a few.

It was used to utilize liquid like water in the various process where this can serve or act as a sealant. The operation is simple but potential gas particles or streams may be dangerous and dirty, so the system works without contact with other parts for safety purposes. For versatility, you may use the ones that are designed with a dual-stage since it also works as a compressor. Check out for more info on how it works.

Principle of Operation

Principle of Operation

While this mechanism is working, there would be a ring formation in the body of the machine and this happens through the liquid seal. That’s when the impeller is spinning and during this state, small chambers will be created. This is where the gas particles will be trapped.

The rotor comes with an axis and this will allow the water to empty and fill the chamber per revolution. Since this axis is eccentric from the storage, gas compression is formed when the pumping mechanism is applied. The gas mixture will be handled through a flow path which will be provided by the vacuum inlet as well as the atmospheric discharge ports.

Now, the gas will be dissipated and formed as seal through the compressed heat, while some are discharged. You should know that the discharged residual water as well as the exhaust gas will automatically be separated or removed from the stream of gases. After that, it will head to the house exhaust and then it will return to where the process started.


Impurities, such as slugs, moisture, soft solids, and chemicals are accepted and won’t destroy the pumping system because it will just be washed away through a discharge. Though you need to maintain the functionality of the rotor since it moves. Anyway, it is affordable and it wears less.

The pumping system operates quietly and won’t exceed 85 dBA. This is due to the sealing water’s cool circulation inside the storage or container. Such benefit is experienced even after constantly operating the machine from 29 in HG Vac – atmospheric pressure. That’s why there are bearings that support the shaft where the rotor is mounted.

You should also know that this type of pumping system is environmentally friendly. That’s because there is no need to alter the oil as well as filter, condenser, and oil pan. This only shows that the working area is free from contamination due to sewers. Visit this link and find out how else it will benefit you.

Application Type

A liquid ring system could either single or multiple stages of pumping. For the multiple, there are two stages of compression on the shaft, though the efficiency is reduced because the released vapor pressure diminishes and it is only 25 Torr. While the single-stage produces 35 Torr of space, which is a standard volume of vacuum for usual performances.

We also have the recirculating and non-recirculating applications. The recirculating deals with discharges where particular external equipment is used to separate gas streams and uses a heat exchanger as a cooling system. While the non-recirculating mechanism treats water as waste and to fill in the loss they use cool water.

Since the environment is greatly considered here, it is then taken as a reliable application for industrial purposes. They need to maintain the condenser with steam-turbines to eliminate incondensable gas streams at 30 to 50 mbar vacuum level. This setting applies to paper machines, cartons, or various forms of packaging, while it is also used in other applications like soil remediation where the space will help in draining contaminated water from the ground and petroleum refining where the pumps are applied in distillation.