ULVAC Rotary Piston Pumps – Robust Oil-Sealed Pumps for Industrial Applications
ULVAC rotary piston vacuum pumps represent the most robust category of oil-sealed vacuum pumps, specifically designed for demanding industrial applications with high capacity requirements. These heavy-duty pumps combine large displacement volumes, tolerance to contamination, and reliable continuous operation with Japanese engineering excellence. Perfect for applications requiring rugged, dependable vacuum generation in harsh environments.
🎯 What are Rotary Piston Vacuum Pumps?
Rotary piston vacuum pumps are positive displacement pumps where one or more pistons rotate eccentrically inside a cylindrical housing. Unlike rotary vane pumps with sliding vanes, piston pumps use larger, more robust pistons that can handle higher gas loads and contamination while delivering very high pumping speeds.
⚙️ Operating Principle:
- Eccentric rotor(s) rotate inside cylindrical stator housing
- Large pistons are mounted on eccentric rotor, creating working chambers
- Working chamber volume increases during rotation – gas is drawn in
- Working chamber volume decreases – gas is compressed
- Compressed gas is expelled through outlet valve
- Oil seals clearances, lubricates pistons, and cools the pump
- Continuous rotation creates steady vacuum
✅ Key Advantages of Rotary Piston Technology:
| 🚀 Very High Capacity |
Large displacement per revolution – high pumping speeds (50-500+ m³/h) |
| 💪 Extremely Robust |
Heavy-duty construction handles contaminated gases, dust, particles |
| 🏭 Industrial Duty |
Designed for continuous 24/7 operation in harsh environments |
| 🔧 Tolerant to Contamination |
Can handle some dust, particles, and condensates better than vane pumps |
| ⏱️ Long Service Life |
Fewer moving parts than multi-vane designs = extended maintenance intervals |
| 📊 Constant Performance |
Maintains pumping speed across wide pressure range |
| 💨 Gas Ballast Capable |
Handles condensable vapors with gas ballast system |
| 🔩 Simple Design |
Fewer precision parts than vane pumps = easier maintenance |
📊 ULVAC Rotary Piston Vacuum Pump Range:
🔷 Single-Stage Rotary Piston Pumps
ULVAC offers single-stage rotary piston pumps for applications requiring high capacity at medium vacuum levels.
| Capacity Range | Pumping Speed | Ultimate Vacuum | Power Range |
|---|
| Small Industrial |
50 - 100 m³/h |
10 - 50 mbar (abs) |
2 - 5 kW |
| Medium Industrial |
100 - 300 m³/h |
10 - 50 mbar (abs) |
5 - 15 kW |
| Large Industrial |
300 - 500+ m³/h |
10 - 50 mbar (abs) |
15 - 30 kW |
✅ Single-Stage Features:
- ✓ Very high pumping speeds for rough to medium vacuum
- ✓ Robust construction for demanding applications
- ✓ Simpler design = lower cost and easier maintenance
- ✓ Ideal for backing larger high vacuum pumps
- ✓ Suitable for contaminated gas streams
🔶 Two-Stage Rotary Piston Pumps
ULVAC's two-stage rotary piston pumps deliver deeper ultimate vacuum while maintaining high capacity.
| Capacity Range | Pumping Speed | Ultimate Vacuum | Power Range |
|---|
| Small Two-Stage |
50 - 100 m³/h |
0.5 - 5 mbar (abs) |
3 - 7 kW |
| Medium Two-Stage |
100 - 300 m³/h |
0.5 - 5 mbar (abs) |
7 - 20 kW |
| Large Two-Stage |
300 - 500+ m³/h |
0.5 - 5 mbar (abs) |
20 - 40 kW |
✅ Two-Stage Features:
- ✓ Deeper ultimate vacuum than single-stage
- ✓ Higher compression ratio
- ✓ More efficient at lower pressures
- ✓ Better suited for high vacuum backing applications
- ✓ Can handle moderate vapor loads with gas ballast
Available ULVAC rotary piston pump types: Single-stage rotary piston pumps, two-stage rotary piston pumps, industrial rotary piston pumps, oil-sealed piston pumps, high-capacity vacuum pumps, heavy-duty vacuum pumps, backing pumps, roughing pumps, industrial duty pumps, contamination-tolerant pumps
🔩 Construction & Design Features:
⚙️ Core Components:
| Component | Material/Design | Features |
|---|
| Housing/Cylinder |
Heavy-duty cast iron |
Thick walls, integrated oil reservoir, robust construction, thermally stable |
| Eccentric Rotor |
Forged steel |
Hardened surface, precision balanced, oil passages for lubrication |
| Pistons |
Cast iron or steel |
Large diameter, wear-resistant coating, spring-loaded against cylinder wall |
| Inlet/Outlet Valves |
Spring-loaded steel plates |
Self-acting, replaceable, designed for high flow |
| Shaft & Bearings |
Heavy-duty roller bearings |
Oil-bath lubricated, designed for high loads, long service life |
| Shaft Seal |
Mechanical face seal |
Prevents oil leakage, reliable sealing, easy replacement |
| Oil System |
Integrated reservoir with forced circulation |
Large oil capacity (10-50 liters), oil cooler (optional), filtration |
| Cooling System |
Water-cooled jackets or air-cooled |
Controls operating temperature for continuous duty |
🛡️ Special Design Features:
- ✓ Heavy-duty cast iron construction – withstands industrial environments
- ✓ Large oil reservoir – extended operation between oil changes
- ✓ Forced oil circulation – ensures all parts are lubricated
- ✓ Oil cooling system – optional water or air cooling for continuous operation
- ✓ Gas ballast valve – adjustable for handling vapors
- ✓ Oil anti-suck-back valve – prevents contamination on shutdown
- ✓ Robust inlet/outlet flanges – designed for industrial piping
- ✓ Accessible maintenance points – easy oil changes and service
🏭 Primary Applications:
| Industry | Applications |
|---|
| 🔥 Metallurgy |
Vacuum furnaces, heat treatment, degassing, steel production, vacuum melting, induction furnaces |
| 🏗️ Vacuum Coating (Large Scale) |
Large coating chambers, metallization, web coating, architectural glass coating |
| 💊 Pharmaceutical (Production Scale) |
Industrial freeze dryers, large-scale lyophilization, vacuum drying plants |
| 🧪 Chemical Industry |
Large-scale vacuum distillation, polymerization reactors, drying processes, degassing |
| 🥫 Food Processing |
Industrial freeze drying, vacuum packaging lines, food dehydration, concentration |
| 🏗️ Plastics Processing |
Large thermoforming machines, extrusion degassing, polymer processing |
| 🔬 Research Facilities |
Large vacuum chambers, space simulation, particle accelerators (backing pumps) |
| 🏭 General Industrial |
Transformer impregnation, vacuum casting, resin impregnation, material handling |
💡 Rotary Piston vs. Rotary Vane – Key Differences:
| Feature | Rotary Piston | Rotary Vane |
|---|
| Typical Capacity |
50 - 500+ m³/h ✅ Higher |
2 - 100 m³/h |
| Construction |
Heavy-duty, robust ✅ |
Lighter, more compact |
| Contamination Tolerance |
Better ✅ |
More sensitive |
| Ultimate Vacuum (Two-Stage) |
0.5 - 5 mbar |
< 0.001 mbar ✅ Better |
| Maintenance Intervals |
Longer ✅ |
More frequent |
| Size & Weight |
Larger, heavier |
More compact ✅ |
| Typical Use |
Industrial high-capacity ✅ |
Laboratory, analytical |
| Cost |
Higher for equivalent capacity |
Lower ✅ |
✅ Choose Rotary Piston Pumps When:
- Very high pumping speeds required (> 100 m³/h)
- Industrial-scale applications
- Gases contain some contamination or particles
- Continuous 24/7 operation needed
- Rugged, robust pump required
- Large vacuum chambers or processes
- Backing pump for large diffusion or Roots pumps
- Harsh industrial environment
✅ Choose Rotary Vane Pumps When:
- Lower pumping speeds sufficient (< 100 m³/h)
- Deeper ultimate vacuum critical (< 0.001 mbar)
- Laboratory or analytical applications
- Clean, dry gases
- Compact footprint important
- Lower initial cost desired
🌡️ Cooling Systems:
💧 Water-Cooled (Standard for Industrial Use):
- ✓ Cooling water jackets in housing and oil cooler
- ✓ Maintains optimal temperature during continuous operation
- ✓ Allows higher capacity and longer duty cycles
- ✓ Extends oil life through better temperature control
- ✓ Typical water flow: 10-50 l/min depending on size
- ✓ Best for: Continuous 24/7 operation, high ambient temperatures
💨 Air-Cooled (Optional for Smaller Units):
- ✓ Cooling fins on housing exterior
- ✓ No water supply required
- ✓ Simpler installation
- ✓ Limited to lower duty cycles or smaller pumps
- ✓ Best for: Intermittent operation, locations without water
💨 Gas Ballast System:
Like rotary vane pumps, rotary piston pumps feature adjustable gas ballast valves for handling condensable vapors:
| Function | Benefit |
|---|
| Admits air during compression |
Prevents vapor condensation inside pump |
| Keeps vapors gaseous |
Protects oil from contamination |
| Adjustable opening |
Optimizes for different vapor loads |
| Essential for wet processes |
Extends pump life in demanding applications |
🔧 Maintenance & Service:
📅 Maintenance Schedule:
| Task | Interval | Description |
|---|
| Daily Inspection |
Daily |
Visual check, listen for unusual noises, check temperature, oil level |
| Oil Level Check |
Weekly |
Check oil sight glass, top up if below minimum |
| Cooling Water Check |
Weekly |
Verify water flow, check for leaks, clean screens |
| Oil Condition Check |
Monthly |
Check for discoloration, contamination, moisture (cloudy oil) |
| Oil Change (Clean Gases) |
6-12 months |
Drain, flush, refill with specified oil |
| Oil Change (Contaminated) |
3-6 months |
More frequent for vapors, particles, or harsh conditions |
| Oil Filter Cleaning |
6 months |
Clean or replace oil filter elements |
| Valve Inspection |
Annually |
Check inlet/outlet valves, clean or replace if worn |
| Piston Inspection |
1-2 years |
Check piston wear, springs, sealing edges |
| Major Service |
3-5 years |
Replace pistons, valves, seals, bearings as needed |
| Complete Overhaul |
7-10 years |
Full disassembly, reconditioning, part replacement, testing |
⏱️ Expected Service Life:
- ✓ Pistons: 10,000-20,000 hours typical
- ✓ Valves: 15,000-30,000 hours
- ✓ Bearings: 30,000-50,000 hours with proper maintenance
- ✓ Overall pump life: 20-30+ years with proper care and overhaul
🔧 Common Wear Parts:
- Pistons – primary wear part, check for edge wear
- Piston springs – maintain tension for proper sealing
- Inlet/Outlet valves – high-flow valves subject to wear
- Shaft seals – replace if oil leaking
- Bearings – long life with proper oil maintenance
- O-rings & gaskets – replace during overhaul
- Oil filters – clean/replace regularly
🛢️ Oil System & Specifications:
Oil Requirements:
| Application | Oil Type | Change Interval |
|---|
| Clean, Dry Industrial Gases |
Mineral vacuum oil ISO VG 68-100 |
12 months |
| Moderate Vapor Loads |
Standard vacuum oil with gas ballast |
6 months |
| Heavy Contamination |
Frequent oil changes or synthetic oil |
3 months |
| Corrosive Applications |
Synthetic or perfluorinated oil |
6-12 months |
💡 Oil Maintenance Tips:
- ✓ Use only manufacturer-specified oil – critical for performance
- ✓ Large oil capacity means oil lasts longer but requires more oil for changes
- ✓ Install oil cooler for continuous heavy-duty operation
- ✓ Monitor oil condition – change when contaminated regardless of interval
- ✓ Use oil filtration system for extended oil life
- ✓ Warm up pump before starting process – ensures proper oil circulation
⚠️ Operating Considerations:
✅ Best Practices:
- ✓ Ensure adequate cooling water flow (for water-cooled models)
- ✓ Allow pump to warm up before full load
- ✓ Monitor oil temperature – should not exceed 80-90°C
- ✓ Open gas ballast when pumping vapors or wet gases
- ✓ Install inlet filter to protect from large particles
- ✓ Use bypass line for startup if backing high vacuum pump
- ✓ Provide adequate ventilation around pump
❌ Avoid:
- ❌ Running without proper oil level – destroys pump
- ❌ Inadequate cooling water flow – causes overheating
- ❌ Pumping large amounts of liquids – use cold trap or separator
- ❌ Exceeding maximum inlet pressure – can damage valves
- ❌ Ignoring oil condition – contaminated oil reduces life
🌟 Why Choose ULVAC Rotary Piston Pumps?
| 🇯🇵 Japanese Quality |
ULVAC precision manufacturing and reliability since 1952 |
| 🚀 High Capacity |
50-500+ m³/h – handles large industrial processes |
| 💪 Industrial Robustness |
Heavy-duty construction for continuous 24/7 operation |
| 🔧 Contamination Tolerant |
Handles some dust and particles better than vane pumps |
| ⏱️ Long Service Life |
20-30+ years with proper maintenance |
| 🔩 Simple Design |
Fewer precision parts = easier maintenance than vane pumps |
| 💰 Low Operating Costs |
Extended oil change intervals, long component life |
| 🌍 Proven Worldwide |
Thousands of installations in demanding industrial applications |
🔧 Our Service for ULVAC Rotary Piston Pumps:
| 🛒 Sales |
Complete range of ULVAC industrial rotary piston pumps – single and two-stage |
| 🎯 System Design |
Application engineering, pump sizing, system integration |
| ♻️ Complete Overhaul |
Full reconditioning: piston replacement, valve service, bearing renewal, testing |
| ⚙️ Repair |
Expert repair of all components, performance restoration |
| 📦 Spare Parts |
Genuine ULVAC parts: pistons, valves, seals, bearings, filters |
| 🛢️ Vacuum Oil |
Bulk vacuum oil supply for industrial applications |
| 🚗 On-Site Service |
Installation, commissioning, maintenance, troubleshooting at your facility |
| 🔍 Performance Testing |
Pumping speed measurement, ultimate vacuum testing, efficiency analysis |
Need a ULVAC Rotary Piston Vacuum Pump?
Whether single-stage rotary piston pump for high-capacity rough vacuum, two-stage rotary piston pump for deeper vacuum with large volume, or complete industrial vacuum system – our ULVAC experts are happy to help you select and implement the optimal rotary piston pump solution for your demanding industrial application.
Perfect for: Vacuum furnaces, large coating systems, industrial freeze dryers, chemical processing plants, metallurgical applications, and any high-capacity industrial vacuum process requiring robust, reliable performance.
Japanese industrial quality and precision – professional local service! Contact us today for expert consultation and proven heavy-duty vacuum technology.
