Replacement Seal for Macro Technologies CryoMac® 3 / 3-50M LNG Nozzle

1. The Problem: Leakage in CryoMac® 3 LNG Nozzles

CryoMac® 3 and 3-50M nozzles are widely used in LNG fueling stations and vehicle refueling systems.

Despite their robust design, leakage during or after fueling remains a frequent maintenance issue.

Leakage typically occurs in two modes:

• Coupled leakage — LNG or vapor escapes during fueling;
• Uncoupled leakage — vapor continues to vent after the nozzle is disconnected.

Both are caused by degradation of the nozzle’s primary sealing components, which must function reliably at −196 °C and up to 500 PSIG (34.5 bar).

2. Root Cause Diagnosis

A. External Seal Leakage (During Fueling)

When the nozzle is coupled, an external seal prevents LNG escape between the nozzle shroud and the vehicle receptacle.

Over time, this seal can lose effectiveness due to:

• Ice formation around the sealing lip;
• Abrasive particles from the dispenser line;
• Repeated thermal contraction and expansion cycles.

Actionable Tip:

Before each fueling, clean both nozzle and receptacle faces with dry nitrogen or clean compressed air to prevent ice and debris buildup.

B. Internal Seal Leakage (After Disconnection)

When the nozzle is removed but residual vapor continues to leak, the internal poppet or check-valve seal is likely worn or scratched.

The seal’s edge must remain perfectly smooth to maintain pressure isolation.

Actionable Tip:

Replace the internal seal at the first sign of continuous venting after disconnection to maintain the “no-vent” operation required by ISO 12617.

C. Maintenance Interval

Industry practice recommends inspection after 10 000 operating cycles or whenever any leakage is observed.

Always follow Macro Technologies’ OEM maintenance instructions for the CryoMac® 3 series.

3. The Solution: XHH Seals Replacement Components

XHH Seals provides engineered cryogenic sealing components specifically for LNG fueling nozzles, including replacements compatible with the CryoMac® 3 and 3-50M.

Our engineering focus is on reliability and interchangeability, not speculation.

Each seal is verified against OEM geometry or physical samples before production.

Performance Capabilities

Operates down to −196 °C (−320 °F)

Rated for 500 PSIG (3.45 MPa) working pressure

Exhibits low friction, high wear resistance, and long-term dimensional stability

Manufactured under ISO 9001 quality certification

Data Transparency

Detailed dimensions and materials are confirmed per OEM specification and provided upon customer request after verification.

4. Engineering Principles Behind Cryogenic Sealing

XHH Seals applies proven cryogenic sealing technology originally validated in systems such as the JC Carter 50E701 nozzle series.

Key design principles include:

• Thermal contraction management to prevent gaps at −196 °C;
• Low-permeability fluoropolymers for reduced gas diffusion;
• Spring-energized geometry to maintain constant sealing pressure under fluctuating loads.

These principles are adapted to meet the mechanical and thermal characteristics of the CryoMac® 3 series, ensuring consistent sealing behavior under repeated pressure cycling and fast cooldowns common in LNG fueling.

5. Maintenance & Inspection Guidelines

6. Inquiry and Technical Support

For accurate seal identification and quotation, please provide:

• Nozzle model: CryoMac® 3 / CryoMac® 3-50M
• Leak type: external / internal / preventive maintenance
• Operating conditions: temperature, pressure, media, cycle frequency
• Reference photos or sample dimensions (if available)

Email: xhh@xhh-smartech.com

Manufacturer: XHH Seals — ISO 9001 Certified Cryogenic Seal Manufacturer

Global Export: Supplying OEM-verified replacements to 60+ countries

7. References

→  Replacement Seal for JC Carter 50E701 LNG Nozzle: P/N B78705-6 Technical Specifications