The Marex Valve Control System’s pneumatic actuators can be mounted in the ballast tanks and adjusted with no need for electricity, thus offering a lower-cost control approach.
At the same time, operators increasingly are adopting the safe and environmentally friendly medium air for trimming of ballast tank.
An article published in hydraulicspneumatics explain about pneumatic ballast system.
Here’s an excerpt from that.
What is Trimming?
Water is commonly used in ships to provide stability and counteract against uneven loads. Depending on the weight and distribution of the load in the hull, ballast-valve control systems open or close valves to either flood or empty the ballast tanks within a ship’s hull Known as trimming.
What is pneumatic ballast system?
The pneumatic actuators of the Marex Valve Control System (VCS) can be mounted in the ballast tanks. An active pneumatic position display, the feedback line, sends the valve position to a controller without current, ensuring reliable monitoring. This system uses pneumatic valve actuators to control ballast, even if a power outage occurs.
It can work up to 100 ballast and quick-release valves, including air preparation and all necessary operating and control modules. The standard working pressure is 5 to 7 bar, and if a power failure occurs, the crew can generate working pressure using one or more manual pumps.
Problem with hydraulic system
Traditionally, Rotary hydraulic valve actuators have been used to trim operations. Hydraulic actuators are small and powerful, but they require two fluid lines, one for supply and one for return.
Today’s increased environmental awareness, the potential for fluid leaks becomes an issue.
Problem with electrical system
Electrical valve actuators could also be used, but ensuring safe operation in these rugged, underwater applications makes them expensive.
How it’s work?
Marex AMC operating and control modules can control the ballast-valve control system. This automation system, used extensively in shipping, allows structured access to all ballast-valve control-system information and functions. Furthermore, it groups and displays additional systems, such as the engine, reversing gear, and other functions.
The modular system communicates with the ballast-valve control system via CAN bus. It is a self-explanatory touchscreen controller that mimics the ship’s movements and simplifies operation.
If the main system fails, the valves can be controlled via a backup control and backup system, which are located outside the engine control room. This includes one or more manual pumps that ensure the ability to function in the event of a power outage.
Advantage
- No electrical connections or power supply required.
- Low maintenance cost.
- No risk of oil leakage (pollution) in the in or outboard water.
- The system has to continue functioning if a power failure occurs, even if the valves are completely submerged.
- Cost of installation is relatively low.
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Source: hydraulicspneumatics.com
