Key Components and Features:

1. Tank (Vessel):

   • Material: Typically constructed from high-strength steel (e.g., carbon steel or alloy steel) that can withstand significant internal pressure.
   • Shape: Usually cylindrical with dished (spherical or elliptical) ends to distribute pressure evenly and maximize volume.
   • Design Pressure: Built to handle high operating pressures, often exceeding 1.7 MPa (around 250 psi) or more, depending on the specific LPG composition and regulations.
   • Insulation/Cladding: Some trailers may have insulation and an outer cladding to help maintain temperature, though many are uninsulated for LPG.
   • Internal Baffles: May be included to reduce liquid surge during transit, improving stability.

2. Chassis and Running Gear:

   • Heavy-Duty Frame: A robust steel frame supports the tank and connects to the tractor unit.
   • Axles and Suspension: Multiple axles (tandem or tridem) with specialized suspension systems (e.g., air suspension) to carry the heavy load and provide a smoother ride.
   • Wheels and Tires: Heavy-duty wheels and tires designed for high loads.

3. Valves and Piping System:

   • Fill/Discharge Valves: High-pressure valves for loading and unloading LPG. These are often designed to be self-closing or have safety features.
   • Vapor Return Valves: For transferring vapor during filling or for vapor balancing between tanks.
   • Safety Relief Valves (PSVs): Crucial safety devices that automatically release excess pressure to prevent tank rupture.
   • Level Gauges: To indicate the amount of LPG in the tank (e.g., float gauges, differential pressure gauges).
   • Pressure Gauges: To monitor the internal pressure of the tank.
   • Emergency Shut-off Valves (ESVs): Allow for rapid closure of all connections in an emergency.
   • Piping: High-pressure rated piping connecting the valves and fittings.

4. Tractor Unit Connection:

   • Fifth Wheel Coupling: Standard connection point for the tractor unit.
   • Brake and Electrical Connections: Standard connections for the tractor’s braking system and electrical power.

5. Safety Features:

   • Emergency Shut-off Systems: Often remotely activated or automatically triggered.
   • Fire Protection: May include fire-resistant materials or systems.
   • Grounding Points: For static electricity discharge.
   • Impact Protection: Guards around valves and fittings.