Details

Introduction
Oxygen systems in aircraft and aerospace applications demand the highest integrity: even minute leaks can pose serious safety risks—fire hazards in enriched-oxygen environments, system failures at altitude, and non-compliance with military and NASA standards. The KU-
7 Oxygen Tester uses high-purity nitrogen as an inert test medium to eliminate combustion risk during pressurization. Its dual-range capability (up to 4000 psi and down to 50 psi) covers both qualification (high-pressure endurance) and acceptance (fine-leak characterization) regimes, per guidelines in NASA-STD-7012 for leak-test sensitivity (down to ~1×10−4 mbar·L/s). Mounted on a compact trolley, the tester travels easily from hangar bay to flight-line, enabling on-site verification without dismantling large assemblies.

Key Features
- Dual-Stage Pressure Control: Two independent regulators tame shop-air (6,000 psi) down to test pressures of 4,000 psi (qualification) and 50 psi (acceptance), supporting rapid switch-over between test modes.
- High Sensitivity Leak Detection: Chamber and gauge calibration ensure detection of leaks as small as 1×10−4 mbar·L/s, compliant with aerospace leak-test requirements.
- Robust Chamber Design: Precision-machined mild-steel chamber with O-ring seals and quick-release clamps maintains uniform gasket compression, delivering consistent dwell-time pressure hold tests.
- Integrated Flow Monitoring: A rotameter (0–6 SCFH) allows trace-gas methods (e.g., helium sniff) and confirms purge rates for rapid localization of leaks.
- Safety Protections: Dual pressure-relief valves (0–10 bar) and color-coded warning labels mitigate overpressure incidents, while needle-valve arrangements isolate test circuits before venting.
- Data Logging (Optional): Add-on digital transducers and USB/ethernet output enable automated test reports and trend-analysis for recurring maintenance.
- Portability & Ergonomics: Lockable swivel casters, integrated handle, and a footprint under 2 ft2 let technicians maneuver in tight spaces without cranes or dollies.

Applications
• Aircraft Oxygen Supply Maintenance: Verification of regulators, manifold assemblies, and pressure-demand valves during scheduled A-checks and C-checks, ensuring leak-tight integrity before flight.
• Defense Subsystems QA/QC: Factory acceptance testing of breathing-air packs and escape-system bottles to MIL-PRF-25567 standards for oxygen leak-detection compounds.
• Spaceflight Hardware Validation: Pre-launch inspection of portable life-support units and EVA backpacks, tailored to meet NASA and DoD leak-test protocols.
• Laboratory & R&D Prototyping: Rapid research-bench checks on novel valve designs, materials compatibility studies under oxygen service, and developmental test cycles for new gas-handling components.

System Description
1. Leak Chamber: 10 × 20 in. cylindrical vessel, chrome-plated interior, with six port fittings for various UUT geometries.
2. Pressure Regulators & Gauges: Precision back-pressure regulators with ±0.5% full-scale accuracy; gauges cover 0–8600 psi, 0–140 psi, and 0–60 psi ranges.
3. Needle Valves & Isolation: Five metering valves (1⁄4′′ OD tubing, 345 bar rating) route gas to test ports, purge lines, and relief vents; quick-disconnect fittings permit rapid reconfiguration.
4. Flowmeter (Rotameter): Glass tube with a stainless-steel float, readable to ±2% accuracy for flow-rate verification before sealed-chamber tests.
5. Safety Valves: Two spring-loaded relief valves calibrated at 10 bar; built-in burst discs for catastrophic-event protection.
6. Chassis & Mobility: Welded tubular-steel frame, powder-coated for corrosion resistance, with four 5′′ polyurethane wheels (two locking) and ergonomic tug handle.

Technical Specifications

  

    

      
Parameter
      
Specification
    
  
  

    

      
Drive Air Pressure
      
4–8 bar (60–120 psi)
    
    

      
Drive Air Flow
      
10–80 scfm
    
    

      
Drive Ratio
      
75:1
    
    

      
Inlet N₂ Pressure Range
      
20–150 bar (300–2 175 psi)
    
    

      
Max Outlet N₂ Pressure
      
300 bar (4 350 psi)
    
    

      
Displacement per Cycle
      
1.2 in³ (≈19.6 mL)
    
    

      
Max Cycle Rate
      
60 cycles/min
    
    

      
Weight
      
27 lb (12.2 kg)
    
    

      
Frame Dimensions (L×W×H)
      
750 × 450 × 540 mm
    
    

      
Gas Connection
      
Interchangeable 3/8″ SAE or 1/4″ H/P
    
    

      
Material
      
Stainless-steel booster; MS frame
    
    

      
Control Elements
      
Festo filter, regulator, ball valves
    
  


Operating Overview
7. Setup & Pre-Check: Connect shop-air/nitrogen supply (6,000 psi), verify regulator setpoints, purge lines at 3 SCFH for 30 s.
8. UUT Installation: Mount component inside chamber; attach port adaptors; tighten quick-release clamps.
9. High-Pressure Test: Isolate purge; pressurize to 4,000 psi at 200 psi/min to minimize thermal effects, hold for 10 min, monitor gauge drift (<1% drop allowed).
10. Low-Pressure Test: Vent chamber; reset regulator; pressurize to 50 psi, hold for 5 min, check no audible or gauge-indicated leakage.
11. Leak Localization: Introduce a helium tracer (1% by volume) and sweep chamber exterior with a sniff probe via the rotameter line.

Maintenance Guidelines
- Daily: Inspect hoses/fittings for wear; verify regulator knob operation; check relief-valve functionality.
- Weekly: Perform calibration drift check against master gauge; clean chamber interior and seals with oxygen-compatible solvent per ASTM G93.
- Annual: Full gauge and regulator recalibration; replace O-rings and burst-discs; verify rotameter float zero.
- Safety Note: Never introduce lubricants or oils in oxygen circuits. Always bleed residual pressure through dedicated vents before opening the chamber.

Conclusion
With its rigorous adherence to aerospace leak-test standards, dual-range capability, and user-centric design, the KU-7 Oxygen Tester (Model A1580) stands as a cornerstone tool for maintenance, quality assurance, and R&D in oxygen-handling systems. Its portability, high-
sensitivity detection, and modular instrumentation make it uniquely suited to keep critical life-support and propulsion subsystems safe, compliant, and mission-ready.