Introduction
Ejectors are widely used in industrial plants for vacuum generation, gas removal, and fluid mixing. They operate without moving parts, making them highly reliable and low maintenance.
Short Answer
An ejector is a device that uses a high-pressure fluid to entrain and transport another fluid, creating suction or vacuum.
What Is an Ejector?
An ejector works based on the Venturi effect. A high-pressure fluid (motive fluid) flows through a nozzle, converting pressure energy into velocity.
This high-speed jet creates a low-pressure region that draws in another fluid (suction fluid). Both fluids then mix and are discharged together.
How an Ejector Works
- High-pressure fluid enters the nozzle
- Velocity increases and pressure drops
- Low pressure creates suction
- Secondary fluid is entrained
- Mixed fluid is discharged through diffuser
Main Components
- Nozzle
- Suction chamber
- Mixing section
- Diffuser
Types of Ejectors
Steam Ejector
Used for vacuum generation in chemical plants and refineries.
Air Ejector
Used in ventilation and gas handling systems.
Liquid Ejector
Used for mixing liquids or pumping fluids without mechanical pumps.
Applications
- Vacuum systems
- Chemical processing
- Gas removal
- Cooling water systems
- Wastewater treatment
Advantages
- No moving parts
- Low maintenance
- High reliability
- Can handle corrosive fluids
Disadvantages
- Low efficiency compared to pumps
- Requires high-pressure motive fluid
- Performance depends on operating conditions
Ejector vs Pump
ItemEjectorPump Moving partsNoneYes MaintenanceLowMedium EfficiencyLowHigh Vacuum capabilityStrongLimited
Conclusion
Ejectors are simple and robust devices used for suction and mixing in industrial systems. Although less efficient than pumps, their reliability makes them essential in many applications.
