Working of a Vacuum Pumps
The various phases leading from suction to compression.
Graphic courtesy of TravainiPompe SpA.
Components of a Liquid Ring Vacuum Pump, and their Main Roles
- Casing
The outer shell that houses all the internal components. It provides structural support and contains the sealing liquid. - Impeller
The rotating component with blades.
It is positioned eccentrically within the casing, creating a crescent-shaped liquid ring. - Liquid Ring
The ring of liquid (usually water) that forms inside the casing due to the impeller’s rotation. It acts as a sealant and creates the compression chambers. - Suction Port
The inlet where the gas or vapor to be evacuated enters the pump. - Discharge Port
The outlet where the compressed gas and some of the sealing liquid are expelled. - Sealing Liquid Supply
A connection to introduce the sealing liquid into the pump. - Separator
A chamber where the discharged gas and liquid are separated.
The liquid is often recirculated back into the pump.
These pumps use a rotating eccentric impeller and a ring of liquid (in blue) to create a vacuum.
The liquid ring is created by the centrifugal force generated by the impeller,
The process has the following stages:
The Various Phases
Suction Phase (I)
Gas enters the pump through the suction port (section A to B). The gas is drawn into the spaces between the blades, which are inside the pump casing.
The impeller is in a casing with a sealing liquid (usually water, but other liquids can be used).
As the impeller rotates, the liquid is forced outwards, forming a ring against the casing walls.
The rotor’s eccentric position causes the volume of the spaces and liquid ring to change as the impeller turns.
As the impeller turns, the volume between the blades and the liquid ring gradually increases. This makes a vacuum that draws gas into the pump from the process.
Compression Phase (II)
As the impeller keeps rotating, the gas between the blades is carried along the casing to the discharge port (C to D). The volume between the blades and the liquid ring decreases during this part of the cycle.
The liquid ring compresses the gas because it is in a larger space in the pump casing.
The liquid ring moves closer to the impeller hub, reducing the space for the trapped gas. The gas pressure rises as it gets closer to the discharge port. The gas and sealing liquid are then expelled through the discharge port.
Discharge Phase
The gas reaches the discharge port in the last stage.
The gas and sealing liquid are released from the pump.
The discharged liquid carries away heat, preventing overheating and maintaining efficiency.
A small amount of sealing liquid is lost with each cycle, so a continuous supply is needed. This liquid maintains the pump’s performance and temperature.
SPS Pumps, The Experts You Need
SPS Pumps works with Travaini Pumpe – reliable and efficient liquid ring vacuum pumps for industrial use.
With years of experience in providing vacuum solutions, we understand the unique challenges faced by different industries.
Our team of experts will support you every step of the way, from selection and installation to maintenance and spare parts supply.
Call us now at +32 2 657 23 53 or email us at info@sps-pumps.com.
The chart is provided courtesy of TravainiPompe SpA.
