They perform a number of different duties both above also below decks. Valves regulate the loading and storage of all some form of energy to power their engines. Of courses, marine valve handling seawater must be hearty and designed to withstand the rigors of a harsh seawater environment.
On a diesel, tugboat may only be one fuel valve. But large cargo ships may have a complicated system of pumps and multiple valve directing the fuel to various tanks on the ship. In another hand, the large ship needs these tanks to aid in the ballasting of the vessel and they put them are located at strategic points on a ship. In this case, they may use piping and valves that are a hand-held size or as large as NPS 30.
The Firefighting piping systems are so important. As we know, on ships, there are no local fire departments to call in case of an emergency at sea. So, Firefighting system valve must work when the fire happens, because of that, their valve have to be ultra-reliable.
Marine valve must have stout exterior to hold up against the corrosive seawater environment. With the ships carrying liquid cargo obviously, have a need for extensive piping systems. These vessels are loaded with valves of every description. The valve need to be carefully selected to handle the products that run through them, such as petrochemicals or cryogenic LNG.
The most common valves on ships and barges were gate, globe and check valve for nearly a hundred years.
Nowadays, ships and barges are home to virtually every type of modern valve. Instead of the gate valve, globe valve or check valve, Ball valves are increasingly popular, including metal-seated types. But, the butterfly valve has probably made more inroads then any type in this segment. Because of the design of butterfly valve is smaller and lighter that is suit for many marine applications.
In fact, automation has become very common on modern ships and automated valve packages are seen more and more in the engineering rooms. These systems interface with sophisticated computer systems that are used to control all of the common shipboard engineering functions.
At the sea, water hard on piping systems because of oxidation. So that, even marine valve materials for freshwater applications must be chosen carefully and replacing the previously common carbon steel materials with the stainless-steel valve and piping systems are being installed in freshwater marine applications.
A different case is Saltwater. A carbon steel piping system will not last for any length of time in a salt-water environment. Then, Bronze valves or iron valve with bronze trim were the most common seawater service marine valves for a long time.
Stainless steel valves
Especially, Titanium with extremely good corrosion resistance and that is the most interesting material choice today. Titanium has other advantages for the marine environment consisting of the high strength and more importantly is lightweight.
The Navy always chose the titanium piping systems because of titanium valve are particularly long-lived (Maybe, titanium valves will even outlast the ships in which they are installed) and require much less repair than other valves although they seem expensive.
Titanium piping systems are easy to fabricate and install but it is a tricky process to attach a titanium valve to non-titanium piping components because of the possibility of galvanic corrosion. The solution is, has to use Insulating bolt sleeves and gaskets must be used to keep this type of corrosion from occurring.
When Valves for use by the Navy, they must meet even stricter standards. Most of these valve are Navy-owned designs that are built per quotation for each specific ship-building project. Prospective bidders must meet the Navy’s stringent quality requirements before they are allowed to bid on a valve package.
From A to Z, tankers of all sizes are covered with valve. A special type of tanker – the LNG ship, it requires unique product piping and valving systems.
Commonly, a Navy shipbuilding program consumes thousands of valves yearly, with needs depending upon which types of ships are built. These projects could require nuclear-grade pressure seal valves, titanium butterfly valves, Ni/Cr ball valves or even mundane bronze gate and globe valves. Not only a Navy shipbuilding program, also in the mining industry, they have to require replace a performance valves. But, that is another story of the valve…