Four-Port Emergency Relay Valve – Multi-Channel Pressure Control Core for Semi-Trailer Brake Systems

Description

The Four-Port Emergency Relay Valve (Part No. 9710020400) is a multi-channel pneumatic control core for semi-trailer brake systems, designed for EBS/ABS 4S/2M compliance with ISO 1215 and SAE J1409. Featuring a ​high-strength aluminum alloy body (anodized) and ​stainless steel pilot spool (≥HRC 58), it integrates ​4 independent pneumatic ports (2 in/2 out) to deliver 0.8MPa brake chamber pressure within 0.1s during emergencies (leakage ≤0.05mL/min @1.0MPa). Its ​EPDM dynamic seals (-50℃~150℃) and ​PTFE guide rings ensure airtightness and wear resistance (≥1 million cycles).

Core Functions:

1. ​Redundant Control: Dual inlet ports (primary/backup) auto-switch to maintain pressure during failures.
2. ​Rapid Response: Pilot-operated structure achieves ≤0.15s full-stroke response.
3. ​Pressure Balancing: 45mm balance diaphragm limits inter-axle pressure deviation to ≤5%.

Key Importance:

• ​Safety Critical: Ensures braking reliability on steep grades or heavy loads.
• ​Material Impact:
  • ​Lightweight: Aluminum body reduces weight by 50% vs. cast iron.
  • ​Precision Engineering: Laser-drilled stainless spool ensures accuracy.
  • ​Seal Durability: EPDM resists brake fluid (DOT3/4) degradation.

Replacement Guidelines:

1. ​Orientation: Align valve arrow with airflow.
2. ​Pressure Sync Test: Post-installation differential ≤0.03MPa.
3. ​Seal Replacement: Replace dynamic seals every 2 years or 200,000 km.
4. ​Cleanliness: Use ISO 8573-1 Class 3 air to purge contaminants.