How Does a Vacuum Generator Work?
A vacuum generator removes air from a connected space, lowering its pressure below the surrounding atmospheric pressure.
In a vacuum handling system, this space includes the suction cups and connecting lines. When a cup forms a seal against the workpiece, the pressure difference across the contact area produces holding force.
The generator must remove enough air to establish the required vacuum and manage any air entering during operation.
From Air Removal to Gripping Force
Before evacuation, the pressure inside an open suction cup is approximately equal to the surrounding pressure.
After the cup contacts the workpiece, the generator removes air from the enclosed space. Pressure inside the cup falls, while atmospheric pressure remains outside.
The ideal normal holding force can be expressed as:
Holding force = pressure difference × effective suction area
This relationship explains why both cup area and operating vacuum matter. Actual handling capacity also depends on the cup design, surface, load direction, friction, acceleration and appropriate design margins.
Use our vacuum suction cup selection guide when reviewing the gripping arrangement.
How Different Vacuum Sources Remove Air
Pneumatic Vacuum Ejectors
Compressed air expands through a nozzle and forms a high-speed jet. The jet entrains air from the vacuum connection and carries it toward the exhaust.
As air leaves the connected suction circuit, its pressure falls.
For a closer look at the nozzle, ports and controls, read our vacuum ejector working principle guide.
Mechanical Vacuum Pumps
In a positive-displacement pump, expanding chambers receive air from the inlet. The mechanism then isolates and transports this air toward the outlet, where it is discharged.
Repeated operation removes air from the connected system. The exact chamber arrangement depends on the pump design.
Peniup Vakum
In a side-channel blower, a rotating impeller repeatedly transfers energy to the air. This creates airflow through the unit and a pressure difference between its inlet and outlet.
Connected to the inlet, a vacuum handling circuit can use this airflow to remove incoming air.
For application differences, see our comparison of vacuum generator types.
The Vacuum Handling Cycle
1. Contact
The suction cup reaches the workpiece and establishes contact. The quality of this seal affects subsequent evacuation.
2. Evacuation
The source removes air from the cups and connected lines. Evacuation time depends on the volume, flow performance, restrictions and leakage.
3. Vacuum Confirmation
A vacuum sensor or switch provides pressure information to the machine control. The gripping threshold should match the application’s requirements.
4. Holding and Movement
During transfer, the system maintains the required vacuum. Depending on the circuit, the source may run continuously or operate under a control strategy.
5. Release
The circuit admits air so that the pressure difference falls. Some systems use controlled blow-off to assist release.
Vacuum Level and Suction Flow Are Different
Vacuum level describes pressure. Suction flow describes the amount of air the source removes per unit of time under stated conditions.
A sealed circuit may require relatively little ongoing flow after evacuation. A leaking or porous workpiece can require continuous airflow to maintain the same vacuum level.
This is why maximum vacuum alone does not describe a generator’s suitability. The available flow at the operating vacuum matters.
What Does a Reservoir Add?
A reservoir adds evacuated volume to the circuit. It may help buffer short changes in demand when integrated with suitable valves and controls.
It does not create vacuum, and it cannot maintain the required pressure indefinitely while air continues entering.
See BVR vacuum reservoir tanks for product and selection information.
Why Might Vacuum Build Too Slowly?
Possible causes include excessive connected volume, insufficient source capacity, restricted tubing, a contaminated filter or leakage at the workpiece.
Measure pressure at relevant points in the circuit. A strong vacuum near the source does not necessarily mean the suction cups reach the same pressure quickly.
For product selection, explore EUROTECH’s industrial vacuum generators or send us your application details.