ULVAC HELIOT 904D3R — Dry Roots Pump Mobile Cart Helium Leak Detector
The HELIOT 904D3R is the mid-capacity dry Roots pump model in the ULVAC HELIOT 900 series mobile cart range. It uses a dry Roots vacuum pump as its backing pump (250 L/min / 15 m³/h at 50 Hz), providing dry (oil-free) backing without the need for pump oil. The 904D3R is suited for clean environments, high-throughput production, and applications where oil contamination is not acceptable.
Model designation confirmed from ULVAC Components Catalog Vol.11, page 56 specification table (“904D3R”).
Configuration Summary
- Form factor: Mobile cart (444×660×991 mm W×D×H)
- Backing pump: Dry Roots pump (not scroll; Roots-type dry pump)
- Backing pump capacity: 250 L/min / 15 m³/h / 8.8 cfm at 50 Hz
- Pump oil required: No
- Inlet port: KF25 (NW25, ISO)
Technical Specifications
Values confirmed from ULVAC Components Catalog Vol.11, page 56.
| Parameter | Value | Notes |
|---|---|---|
| Model designation | HELIOT 904D3R | Verify against nameplate |
| Detectable gas | ⁴He (helium), H₂ (hydrogen) | Vacuum method |
| Min. detectable leak rate (⁴He) | <5×10⁻¹³ Pa·m³/s | ULTRA flow mode |
| Min. detectable leak rate (⁴He) | <5×10⁻¹² mbar·L/s | ULTRA flow mode |
| Leak rate display — ULTRA (He) | 1×10⁻¹⁴ to 1×10⁻⁶ Pa·m³/s | — |
| Leak rate display — FINE (He) | 1×10⁻¹² to 1×10⁻⁵ Pa·m³/s | — |
| Leak rate display — GROSS (He) | 1×10⁻¹° to 1×10⁻³ Pa·m³/s | — |
| Leak rate display — FINE (H₂) | 1×10⁻⁸ to 1×10⁻⁵ Pa·m³/s | — |
| Inlet pumping speed (He) — ULTRA | 5 L/s | — |
| Inlet pumping speed (He) — FINE | 1 L/s | — |
| Max. inlet pressure — ULTRA | <2 Pa (<0.02 mbar) | — |
| Max. inlet pressure — FINE | <100 Pa (<1 mbar) | — |
| Max. inlet pressure — GROSS | <1,200 Pa (<12 mbar) | — |
| Main TMP | 31 L/s | Turbomolecular pump |
| Backing pump type | Dry Roots pump | Roots-type dry pump; no pump oil |
| Backing pump capacity | 250 L/min / 15 m³/h / 8.8 cfm | At 50 Hz |
| Weight (with cart) | ~72 kg | — |
| Power consumption | 800 VA (50 Hz) / 950 VA (60 Hz) | — |
| Input power | Single phase 100–120 V or 200–240 V AC | — |
| Inlet port | KF25 (NW25, ISO) | — |
| Startup time | <2 min | — |
| Dimensions W×D×H (with cart) | 444×660×991 mm | From catalog; same for all 904 models |
| Interfaces | RS-232C, RS-485, analogue DC, digital I/O | — |
| Controller | 7″ tablet, wireless IEEE 802.11 b/g/n | Standard accessory |
| Standards | CE, IP30 | — |
| Operating temperature | 10–40°C, non-condensing | — |
Dry Roots Pump — What It Is and Why It Matters
The backing pump in the 904D3R is a dry Roots pump (a Roots-type positive-displacement pump operating without oil in the compression mechanism). This is distinct from a dry scroll pump:
| Feature | Dry Roots pump (904D3R, 904D4R) | Dry scroll pump (901D2) |
|---|---|---|
| Oil in compression mechanism | None | None |
| Operating principle | Counter-rotating figure-8 rotors | Orbiting scroll |
| Typical pump speed range | Higher (250–500 L/min) | Lower (90–108 L/min) |
| Seal/wear element | Rotor clearances (no contact seals in compression) | Scroll tip seals (contact wear) |
| Contamination tolerance | Better for high-throughput; tip seal wear less critical | Tip seal wear limits pump life in contaminated environments |
904D3R vs 904D4R
| Factor | 904D3R | 904D4R |
|---|---|---|
| Pump type | Dry Roots | Dry Roots |
| Pump capacity (50 Hz) | 250 L/min (15 m³/h) | 500 L/min (30 m³/h) |
| Power consumption | 800/950 VA (50/60 Hz) | 800/950 VA (50/60 Hz) |
| Weight (with cart) | ~72 kg | ~77 kg |
| Best for | Medium test volumes, mobile, dry operation | Large test volumes, highest throughput, dry operation |
Dry Roots Pump Service Points
- No oil required: No oil level check, no oil change. Dry Roots pumps use oil only in the gearbox and bearing chambers, not in the gas compression path.
- Gearbox oil: Gearbox and bearing lubrication does require periodic oil check and change per the pump manufacturer’s schedule. This is separate from the vacuum system and does not risk contaminating the HELIOT.
- Ultimate pressure monitoring: Check backing pump ultimate pressure periodically to detect rotor clearance deterioration or bearing wear.
- Temperature monitoring: Dry Roots pumps generate heat. Ensure the instrument ambient temperature is within specification (10–40°C) and ventilation is clear.
- Particulate protection: Dry Roots pumps are susceptible to particulate ingestion. Check inline filter at backing pump inlet at each maintenance visit.
Service Enquiry
Email: mail@ulvacheliot.com
Include: model designation from nameplate (HELIOT 904D3R), serial number, fault or service required, facility location.
Repair | Preventive Maintenance | Calibration | Backing Pump Service | Spare Parts | 900 Series overview
Regional Variants and Part Numbers
Note: The HELIOT 904D3R uses a Dry Roots backing pump as specified in the ULVAC catalog. The price list also lists HELIOT 904D3 (without R suffix) with a scroll pump — these are separate products. Part numbers below apply to the 904D3R / 904D3 series; confirm the exact model designation from the instrument nameplate before ordering.
| Model designation | Part number | Supply voltage | Certification | Region |
|---|---|---|---|---|
| HELIOT 904D3-F1A | 210006829700 | AC 100–120 V | PSE / UL / CSA | US / North America |
| HELIOT 904D3-F2B | 210006830200 | AC 200–240 V | PSE / UL / CSA | SE Asia |
| HELIOT 904D3-F2E | 210006831200 | AC 200–240 V | IEC | EU / international |
| HELIOT 904D3-F1Z | 210006875700 | AC 100–120 V | — | Without power supply cable |
| HELIOT 904D3-F2Z | 210006876200 | AC 200–240 V | — | Without power supply cable |