A dry screw vacuum pump is a positive-displacement pump that uses two intermeshing screw rotors to move gas from the inlet to the outlet without using oil or liquid sealing. This makes it ideal for clean, oil-free vacuum applications in industries like semiconductors, pharmaceuticals, and food processing.
Two Helical Rotors (Screws) – A male and female rotor that rotate in opposite directions.
Inlet & Outlet Ports – Gas enters through the inlet and is compressed before exiting.
Cooling System – Air or water cooling prevents overheating (no oil cooling needed).
Motor & Drive System – Synchronized rotation via timing gears or direct drive.
Seals & Bearings – Maintain airtight operation without oil contamination.
Gas Intake
Gas enters through the inlet port as the rotors turn.
The screw threads create expanding chambers that suck in gas.
Gas Trapping & Compression
As the rotors rotate, the gas is trapped between the screw threads and the pump housing.
The volume between the rotors decreases progressively, compressing the gas.
Gas Discharge
The compressed gas moves toward the outlet port.
Once it reaches the outlet, it is expelled into the exhaust system.
Cooling (Critical for Dry Operation)
Air cooling (fins or fans for lower-capacity pumps).
Water cooling (jacketed housing for high-capacity pumps).
Since no oil is used, cooling is done via:
Repeat Cycle
The rotors continue turning, creating a continuous vacuum effect.
✔ Oil-free operation – No contamination risk (ideal for clean industries).
✔ Low maintenance – No oil changes, fewer consumables.
✔ Energy efficient – Better than oil-sealed pumps in many cases.
✔ Handles vapors & particulates – Good for chemical and process industries.
✔ Quieter & smoother than claw or rotary vane pumps.
| Feature | Dry Screw Pump | Oil-Sealed Rotary Vane | Claw Pump |
|---|---|---|---|
| Oil-Free? | ✅ Yes | ❌ No | ✅ Yes |
| Maintenance | Low | High (oil changes) | Medium |
| Gas Handling | Excellent (vapors, dust) | Poor (sensitive to contaminants) | Good |
| Noise Level | Low | Moderate | High |
Semiconductor manufacturing (clean vacuum needed).
Pharmaceutical & food processing (no oil contamination).
Chemical & petrochemical (handles aggressive gases).
Plastic & packaging industries (high reliability).
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