The compressed air system is the “starting bloodline” of a ship. Starting the main engine, starting the generators, operating pneumatic instruments, driving pneumatic valves, and even daily service air on board all depend on compressed air. The air receiver, as the storage vessel for compressed air, has installation quality and safety inspection that directly affect the reliability and safety of the entire system. Jiangsu Haizhongzhou Shipping Industry Co., Ltd. strictly follows pressure vessel codes and classification society requirements during the installation of air receivers and compressed air piping.
The installation of the air receiver must first satisfy strength and tightness requirements. Before installing an air receiver, Haizhongzhou verifies the manufacturer’s documentation, including material certificates, welding procedure qualification records, heat treatment reports and hydrostatic test records. The hydrostatic test pressure is 1.5 times the design pressure, with a hold time of not less than thirty minutes, and the vessel is accepted if there is no leakage and no visible deformation. During installation, the fixing brackets of the air receiver are securely welded to the hull structure, and rubber pads or wooden pads are placed between the brackets and the receiver to prevent vibration wear. A drain valve is provided at the bottom of the receiver for regular discharge of accumulated water and residual oil; a safety valve is provided at the top, set at 1.05 times the design pressure, which automatically opens to relieve pressure when the internal pressure exceeds the limit.
The installation of receiver accessories has strict orientation requirements. Pressure gauges should be installed in positions that are easy to observe, with no obstacles in front of the dial. The discharge port of the safety valve should face a safe area, not towards personnel passageways or electrical equipment. The outlet of the drain valve should be connected to a bilge water tank or a dedicated collection container, not directly discharged to the engine room floor. After installation, Haizhongzhou performs a system tightness test: dry compressed air is charged into the receiver and piping to the design pressure, and a soap solution is applied to all flange connections, threaded joints and welds to check for bubbles. For micro‑leaks, an electronic leak detector is used to assist in locating them.
The material selection and routing of compressed air piping are equally important. Haizhongzhou selects seamless steel pipes or copper pipes according to the system pressure class. For high‑pressure systems (typically 3 MPa), 20# or higher grade seamless steel pipe is used, with wall thickness calculated based on pressure and added corrosion allowance. Piping connections are mainly welded, with threaded connections used only for instrument interfaces and end branches. The piping should be routed with a slope towards the air receiver (typically 3 to 5 per thousand) so that condensate can flow back to the receiver and be discharged through the drain valve. Automatic or manual drain traps are provided at the lowest points of the piping.
During commissioning, Haizhongzhou performs start/stop tests of the air compressor and pressure switch calibration. When the pressure in the receiver drops to the lower setpoint, the air compressor should start automatically; when it rises to the upper setpoint, it should stop automatically. For systems with automatic drain solenoid valves, the timed drain function is verified. The installation and inspection report for the air receiver and compressed air system is one of the necessary documents for the vessel to obtain classification society certification, and Haizhongzhou completely archives it for each vessel.
