
The marine boiler, one of the most fundamental pieces of machinery aboard a ship, is responsible for generating steam used for propulsion and other onboard systems. With the evolution of shipping technology, boilers have undergone several advancements, making them safer and more efficient. Today, boilers on ships are equipped with various essential fittings, known as boiler mountings, which ensure their safe operation.
These mountings provide the necessary controls to regulate steam production, monitor water levels, manage pressure, and allow for safe maintenance.
In this blog, we delve into the most important marine boiler mountings and explain how they contribute to the overall safety and functionality of the boiler.
Essential Marine Boiler Mountings
Here’s a comprehensive list of boiler mountings essential for safe and efficient boiler operation:
Safety Valves
Water Level Indicators
Water Level Controller
Water Level Alarms & Cut-Out Assembly
Remote Water Level Transmitter
Main Steam Outlet Valve
Pressure Gauge & Pressure Switches
Feed Water Valves
Burner Assembly
Air Vent
Water Sampling Valve
Manholes, Mudholes & Peepholes
Bottom Blowdown Valve
Defoaming (Scum) Valve
Furnace Drain Valve
Soot Blowers
Steam Stop Valve
Feed Check Valves
Water Level Gauges
Air Purge Valve
Pressure Gauge Valve
Scum Blowdown Valve
Below, we explain some of these critical boiler mountings in more detail:
1) Safety Valves
The Safety Valve is one of the most crucial components in a boiler system. Its primary function is to protect the boiler from overpressure conditions. Typically, two or three safety valves are fitted to each boiler: two on the steam drum and one on the superheater outlet header. The superheater valve is designed to lift first, ensuring a continuous flow of steam through the superheater, even under blow-off conditions. These valves are preset by certified authorities to ensure they activate at the correct pressure and prevent any manual tampering.
2) Main Steam Stop Valve
The Main Steam Stop Valve is mounted on the superheater outlet header and is responsible for isolating the boiler from the steam system. In cases where multiple boilers are connected to a common steam line, the main stop valve ensures that steam from other boilers does not enter a damaged boiler, particularly in the event of a pressure drop caused by a burst tube. Some main stop valves come with automatic closing devices for emergency situations, preventing steam from flowing to critical systems like the main turbines.
3) Auxiliary Steam Stop Valve
This valve is a smaller version of the main stop valve, designed to isolate the boiler from the auxiliary steam lines. The Auxiliary Steam Stop Valve is also of the screw-down, non-return type and prevents steam from flowing back into the boiler in case of a system failure. These valves may be mounted on the superheater outlet header, and in some cases, a de-superheater is used to reduce the steam temperature as per the requirements.
4) Feed Check Valves
The Feed Check Valve regulates the entry of feed water into the boiler. It is a non-return valve, preventing boiler water from flowing back into the feed line in the event of a feedwater supply failure. Both main and auxiliary feed checks are fitted, with the main check valve positioned in a convenient location for operation. A clear indication of the valve’s open and closed status ensures safe operation.