ULVAC Oil Rotary Vacuum Pumps
ULVAC oil rotary vacuum pumps back turbomolecular pumps, serve as standalone rough and medium vacuum sources, and are the first-stage pump in oil diffusion pump systems. The range covers single-stage and two-stage rotary vane pumps (PVD series), belt-drive oil-sealed pumps (PKS series), direct-drive two-stage pumps (VD and VS series), hermetic-drive pumps (GHD), and high-displacement pumps (GLD). All models use oil to seal rotor-stator clearances, lubricate vane tips and bearings, and remove heat. A gas ballast valve is standard on most models to handle condensable vapours.
Part Numbers
Product Families
| Series | Type | Speed Range | Notes |
|---|---|---|---|
| PVD-180, PVD-360 | Single-stage rotary vane, direct drive | 180 to 360 L/min | Compact backing pump for TMP, MBP, and diffusion pump systems |
| PKS-016, PKS-030, PKS-070B | Belt-drive rotary vane, two-stage | 16 to 70 m3/h | Belt drive allows motor replacement without internal oil contact |
| VD-30C, VD-60C, VD-90C | Direct-drive rotary vane, two-stage | 30 to 90 m3/h | Medium duty; suitable for process gas loads |
| VS-1501, VS-2401 | Direct-drive rotary vane, single-stage | 1500 to 2400 L/min | High throughput for large chamber roughing and process pumping |
| GHD-031 | Hermetic drive, oil-sealed | 31 m3/h | Hermetically sealed motor for flammable or aggressive process gases |
| GLD-137C | Oil-sealed, large displacement | 137 m3/h | For high gas load process applications |
Oil and Lubrication
Oil is essential to pump operation: it seals the rotor-stator clearance, lubricates the vane tips and bearings, and removes heat. Use ULVAC Ultra Oil or an equivalent fully synthetic vacuum pump oil of the correct viscosity. Do not use general-purpose mineral oil — insufficient vapour pressure properties will degrade ultimate pressure performance.
- Check oil level via sight glass before each shift — oil level must be between MIN and MAX marks with pump at rest
- Oil colour: pale yellow or clear is normal; dark brown or black indicates thermal stress; grey or white milky appearance indicates water contamination — change oil immediately
- Oil change interval: typically 2000 operating hours or annually — shorten significantly for reactive, corrosive, or condensable process gases
- Gas ballast: open when pumping condensable vapours (solvents, water vapour) to prevent condensation in the oil; close gas ballast for dry clean gases to improve ultimate pressure
- Always fit an oil mist separator on the exhaust — prevents environmental contamination and recovers oil carried out as mist
Installation Requirements
- Mount on a level, rigid surface — inclined mounting or vibrating structures are not acceptable
- Fit a solenoid inlet valve that closes automatically on pump stop — prevents oil suck-back into the process chamber on sudden shutdown
- Exhaust: route to scrubber or ventilated area; fit oil mist separator at exhaust port; never discharge to a closed room
- PKS belt-drive models: check belt tension at installation; belt guard must be fitted before operation
- Verify motor rotation direction before first run — wrong rotation causes oil to spray from exhaust port
- Solenoid valve options for PVD-B series available in voltages from AC200V to AC480V — confirm supply voltage when ordering
Pre-Commissioning Checks
- Verify oil level is between MIN and MAX marks
- Confirm motor rotation direction matches rotation arrow on pump body
- Verify exhaust is connected and routed safely
- Blank off inlet with gauge to check no-load performance before connecting to system
- Confirm electrical supply voltage and phase match motor nameplate
- PKS models: check belt condition and tension
Commissioning Sequence
- Open gas ballast valve
- Start pump with blank-off plate on inlet; run 5 minutes to warm up
- Connect calibrated vacuum gauge to inlet; record ultimate pressure with blank-off; compare to specification
- Close gas ballast valve; wait 5 minutes; record improved ultimate pressure (two-stage models should reach specification)
- Connect pump to vacuum system and open inlet valve
- Monitor pump body temperature — steady state is typically 60 to 80 degrees C
- After 30 minutes of operation: re-check oil level with pump warm; top up if necessary
- Record commissioning data: date, pump model, serial number, ultimate pressure blank-off, system base pressure, oil type used
Preventive Maintenance
| Task | Interval | Notes |
|---|---|---|
| Oil level check | Before each shift | Check sight glass; top up with same oil type only |
| Oil condition visual check | Weekly | Colour, clarity, any milkiness indicating water contamination |
| Oil change | 2000 hours or annually | Shorten for corrosive or wet process gases; drain warm oil for complete removal |
| Oil mist trap service | At each oil change | Replace or clean coalescing element; drain collected oil |
| Inlet filter inspection | At each oil change | Replace element if contaminated; blocked filter reduces pumping speed |
| Belt inspection (PKS series) | Every 6 months | Check tension and condition; replace if cracked or glazed |
| Exhaust valve inspection | Annually | Check for cracks, debris, or carbon buildup; replace if necessary |
| Shaft seal inspection | Annually | Check for oil leak at drive end; replace shaft seal if dripping or wet |
| Ultimate pressure test | Annually or after oil change | Record and compare to baseline commissioning value |
Condition-Based Maintenance Criteria
- Change oil immediately if oil is grey/white (water contamination), black (thermal breakdown), or contains visible particulate
- Investigate shaft seal immediately if oil drips are found under the pump at the drive end
- Investigate exhaust valve if: pulsing noise on exhaust, oil spraying from mist trap excessively, or ultimate pressure significantly worse than specification
- Schedule overhaul if ultimate pressure is more than 10 times worse than specification after confirmed fresh oil change and confirmed inlet valve seating
Fault Diagnosis
| Symptom | Probable Cause | Diagnostic Step | Action |
|---|---|---|---|
| Poor ultimate pressure | Oil contaminated; exhaust valve damaged; shaft seal worn; inlet valve leaking | Change oil first; test with blank-off plate on inlet; leak test inlet valve | Change oil; replace exhaust valve; replace shaft seal as indicated |
| Excessive oil consumption | Oil mist trap saturated; oil overfilled; high process gas load | Check mist trap condition and oil level | Service mist trap; verify correct fill level; check gas ballast operation |
| Oil in process chamber | Inlet solenoid valve missing or not closing on stop; reverse rotation | Verify inlet solenoid closes on pump stop; check rotation arrow on pump body | Fit or service inlet solenoid valve; correct motor wiring for rotation direction |
| Abnormal knocking or rattling noise | Debris in pump; vane broken; bearing worn | Stop pump; strain oil through fine filter; check for metal particles | Internal inspection and workshop service required |
| Pump overheating above 100 degrees C | High ambient temperature; cooling fins blocked; wrong oil grade | Check ambient temperature and cooling fin condition | Improve ventilation; clean fins; verify correct oil grade |
| Motor trips on overload | Pump seized or very stiff; wrong supply voltage | Check pump rotates freely by hand with power off before re-starting | Investigate seize cause; verify electrical supply |
| Shaft seal leak at drive end | Shaft seal worn or hardened; excessive exhaust back-pressure | Confirm shaft seal is source of leak not bearing cover | Replace shaft seal; investigate back-pressure cause |
Service Scope
Remote support: oil condition assessment by photo, performance data review (ultimate pressure trend), gas ballast setting advice, oil type verification, rotation direction check by video call.
On-site service: shaft seal replacement, exhaust valve replacement, internal inspection, rotor-stator clearance check, oil flush and change, full performance test post-service.
Workshop overhaul: complete disassembly, clearance measurement to specification, vane replacement, rotor and stator reconditioning or replacement, full performance test before return.
Operator and Maintenance Training
Operator training: daily oil level and condition checks, gas ballast usage, correct startup and shutdown sequences, recognising abnormal noise and oil condition, log-keeping. Maintenance training: oil change procedure, exhaust valve inspection and replacement, shaft seal replacement, oil mist trap service, belt inspection and replacement (PKS series), and performance testing. Contact mail@ulvacheliot.com — provide: pump models, number of attendees, site location, preferred dates.
Service Enquiry
Email mail@ulvacheliot.com — provide: pump model, part number, serial number, oil type in use, operating hours, process gas, symptom description, and photos of oil condition and nameplate.