Two-Stage Liquid Ring Vacuum Pumps

Double stage liquid ring vacuum pump

Two-stage liquid ring vacuum pumps are vacuum systems that are widely used in industrial applications and provide high efficiency. They are preferred in many industries, especially because they can operate under low pressure requirements and achieve high vacuum levels.

Two-Stage Liquid Ring Vacuum Pump

Pomvak’s two-stage vacuum pumps are pumps that can reach a suction capacity of up to 2600 m³/h and a vacuum pressure value of 33 mbar (-735 mmHg).

Pomvak provides the best engineering support for vacuum pump selection with its expertise. With the composite systems it has developed and its expertise in vacuum applications, Pomvak continues to shape the pump industry every day as an innovative and developing company.

Working Principle

Two-stage liquid ring vacuum pumps are dynamic vacuum systems that work on the principle of the liquid ring. These systems use a liquid medium to compress and expel gas. The working principle consists of the following basic steps:

1. Pump Fan and Formation of the Liquid Ring:

• The pump contains a fan that is placed eccentrically inside the pump.
• As the pump fan rotates, the liquid (usually water or a special liquid) inside the pump is pushed outward by centrifugal force, creating a liquid ring on the inner walls of the pump casing.
  2. Gas Suction (First Stage):
• As the fan blades increase in volume, gas is drawn in from the intake port.
• The gas is trapped in the cavities created by the liquid ring.
• As the pump fan rotates, these gas chambers gradually shrink, and the gas is compressed.
• The pressure is reduced to a certain level in the first stage.
  3. Intermediate Stage and Second Stage Compression:
• The gas that is partially compressed in the first stage is directed to the second stage via an intermediate port.
• Here, it is compressed again with the same principle, as the pump fan continues to rotate.
• Thanks to the second stage, it is possible to reach even lower final pressure levels.
  4. Gas Discharge:
• The compressed gas is expelled through the discharge port.
• During discharge, the liquid and gas are separated, and the liquid can either be reused in the pump cycle or discarded.
  5. Cooling and Heat Management:
• The liquid ring absorbs the heat generated during the gas compression process and controls the temperature.
• This provides a more stable operation compared to dry vacuum pumps and prevents overheating.

Two-stage systems are preferred in applications that require higher vacuum pressures because they can reach lower pressure levels compared to single-stage models.

Advantages of Two-Stage Liquid Ring Vacuum Pumps

Two step liquid ring vacuum pump

Two-stage liquid ring vacuum pumps are vacuum systems that can reach lower final pressures compared to single-stage models. They are characterized by high humidity tolerance and resistance to harsh industrial conditions. These pumps stand out with their reliability, durability, and low maintenance requirements. Here are the detailed advantages:

1. Lower Final Pressure (Higher Vacuum Level):

• Thanks to the two-stage design, they can achieve lower pressure levels (down to 0.03-0.05 mbar) that cannot be reached with single-stage pumps.
• This provides an advantage in applications where vacuum levels are critical, such as in the chemical, pharmaceutical, and energy sectors.
• They offer high performance in applications such as distillation, gas removal, and vacuum furnaces.
  2. High Humidity and Vapor Tolerance:
• These pumps perform without performance loss when pumping water vapor and other humid gases.
• Condensation and corrosion issues that are seen in other vacuum pumps are minimized.
• They work safely in humid environments commonly found in industries such as food, pharmaceuticals, paper, and chemicals.
  3. Continuous and Stable Operation:
• They have a long-term, continuous operating capacity.
• They are suitable for harsh industrial conditions and can operate efficiently for 24 hours a day.
• They produce low vibration and noise, providing a more comfortable working environment in factories and production plants.
  4. Resistance to Chemical and Abrasive Gases:
• The internal surfaces of the pump can be protected with stainless steel or special coatings, preventing wear and corrosion caused by aggressive chemicals.
• Used in the chemical, petrochemical, and pharmaceutical sectors, they pump abrasive gases safely.
  5. Energy Efficiency and Low Operating Cost:
• The two-stage design optimizes energy consumption and ensures low-cost operation.
• They require less maintenance compared to oil-sealed vacuum pumps, which reduces operating costs in the long term.
• Due to low friction and wear, they have a long service life.
  6. Oil-Free and Environmentally Friendly Operation:
• They do not produce waste oil or incur oil change costs due to the oil-free system.
• They do not emit harmful oil vapor or particles, providing a clean and safe vacuum source.
• They are ideal for clean production processes in industries like food, pharmaceuticals, and environmental technologies.
  7. Easy Maintenance and Long Service Life:
• The number of moving parts is minimal, reducing mechanical wear.
• They require minimal regular maintenance, only needing periodic liquid level checks and changes.
• They have a long service life and durable construction, which shortens the return on investment period.
  8. Low Noise and Vibration Levels:
• Thanks to the liquid ring design, they produce minimal noise during operation.
• They have a low vibration level and do not require additional anti-vibration equipment.
• They offer a more comfortable working environment in industrial facilities, laboratories, and production areas.
  9. Ability to Pump a Wide Range of Gases and Vapors:
• They can pump a wide range of gases, including heavy hydrocarbons, solvents, acidic and basic gases.
• They ensure safe operation with hazardous or reactive gases in chemical and petrochemical facilities.
• They are used in gas removal applications in the plastic and rubber industries.
  10. Modular and Flexible Design:
• They can be produced with special materials and coatings to suit different applications.
• They can be customized with different capacities and motor options.
• They can operate standalone or be integrated into central vacuum systems.

Two-stage liquid ring vacuum pumps offer significant advantages such as high efficiency, low maintenance requirements, resistance to abrasive chemicals, and long service life. Their energy-saving features, quiet operation, and environmental friendliness make them indispensable in industries such as manufacturing, chemicals, food, pharmaceuticals, and environmental technologies.

pvk 275-260 dual stage vacuum system

PVK 275-260 Two-Stage Vacuum System

Single-Stage vs. Two-Stage Liquid Ring Vacuum Pumps

Summary:

• Single-stage pumps are sufficient for simple and low vacuum applications.
• Two-stage pumps are better for industrial applications requiring higher vacuum, efficiency, and durability.

Application Areas for Two-Stage Liquid Ring Vacuum Pumps

Double stage liquid ring vacuum pump

Two-stage liquid ring vacuum pumps are known for their reliability and durability in industries requiring high vacuum. Their ability to achieve lower final pressures and high humidity tolerance makes them ideal for many sectors. Here are the main application areas:

1. Chemical and Petrochemical Industry:

• Used for transporting, separating, or recovering gases or solvents in chemical production processes.
• Distillation and rectification: These processes require low pressure for the purification of chemicals.
• Vacuum drying: Allows drying of humid chemicals or mixtures containing solvents at low temperatures.
• Reactor vacuum applications: Enables chemical reactions to occur at lower temperatures, offering energy savings.
  2. Food and Beverage Industry:
• Used to enhance product quality and prevent oxidation in food processing.
• Vacuum concentration: Used for concentrating liquids such as fruit juice, milk, and syrup.
• Vacuum drying: Allows delicate food materials to be dried at low temperatures.
• Vacuum packaging: Reduces atmospheric oxygen to extend product shelf life and prevent spoilage.
  3. Paper and Pulp Industry:
• Vacuum pumps are needed to remove moisture during paper production.
• Water removal in paper machines: Ensures effective water removal during the initial stages of paper production.
• Pulp processing and filtration: Helps remove excess liquid during the processing of cellulose fibers.
  4. Electricity and Power Plants:
• Used to enhance efficiency and expel gases in energy production processes.
• Steam condensation systems: Increases condensation efficiency in steam turbines and creates low-pressure vacuum environments.
• Gas removal: Ensures air and gases are removed from water cooling systems.
  5. Environmental Technologies and Wastewater Treatment:
• Used for controlling gases and processing liquids in environmental engineering applications.
• Gas removal and emission control: Used to absorb or expel harmful gases through vacuum processes.
• Vacuum filtration systems: Provides vacuum power for water purification in industrial wastewater treatment plants.
  6. Medical and Pharmaceutical Industry:
• Used in sterile production processes and precise pharmaceutical procedures.
• Vacuum distillation and drying: Important for removing solvents and preserving active ingredients in drug production.
• Sterilization: Used in sterilization processes for hospital and laboratory equipment.
• Lyophilization (freeze-drying): Extends the shelf life of vaccines, biotechnology drugs, and medical products.
  7. Plastic and Rubber Industry:
• Used in gas removal and polymer processing.
• Vacuum molding: Improves product quality by preventing air bubbles in plastic injection and thermoforming applications.
• Degassing: Helps remove volatile chemicals from raw plastic materials.
  8. Metallurgy and Vacuum Furnaces:
• Used for atmosphere control in metalworking and heat treatment processes.
• Vacuum Melting and Casting: Ensures the melting of metal alloys in an oxygen-free environment.
• Vacuum Sintering: Used in the process of fusing metal powders under low pressure.

Two-stage liquid ring vacuum pumps are a reliable solution in many industrial processes due to their high vacuum capacity and moisture tolerance. They are preferred in industries such as chemicals, food, energy, medical, paper, and plastics for their efficient and durable design.

Two stage liquid ring vacuum pump

Two-Stage Liquid Ring Vacuum Pump
Among today’s vacuum technologies, new-generation systems such as dry vacuum pumps and turbo molecular pumps stand out. However, two-stage liquid ring vacuum pumps still offer a significant advantage in processing gases with high moisture content, discharging corrosive gases, and providing reliability in large-volume systems. Compared to dry vacuum pumps, they offer lower maintenance costs and excel in heat management due to the liquid ring. With advancements in environmental regulations and energy efficiency, these pumps are being integrated with modern technologies to become more efficient and sustainable.
Additionally, when combined with vacuum booster systems, higher efficiency and lower final pressure levels can be achieved, providing a broader range of applications in industrial processes. They continue to offer a vital solution for long-term reliability and durability in industrial applications.