What Is Scotch Marine Boiler?
Scotch marine boiler is a common boiler commonly used on ships in marine works. These boilers are a type of fire-tube boiler. Scotch or tank-type marine steam boilers are used for marine works, in particular, because of their compactness, efficiency in operation, & ability to use any type of water.
It does not require a brickworks setting and external flues. In this article, we will learn about the construction, working, advantages, and application of Scotch marine boilers.
It is the most common boiler used on ships in marine works. It is a type of fire-tube boiler. After readings these articles, you will be able to know their construction.
Types of Scotch Marine Boiler:
There are two main types of Scotch Marine Boilers:-
- Single Finished Scotch Marine Boiler.
- Double Ended Scotch Marine Boiler.
#1. Single Finished Scotch Marine Boiler
This boiler consists of a circular boiler shell of a large diameter and a short length. Single-end Scotch boilers have a distance of up to 3.5 meters. It consists of one to four furnaces, and these furnaces enter from the front end of the boiler. The Scotch boiler was a very common marine boiler used in steamships in many countries.
- Single-end steam boilers can have a length of up to 3.5 meters.
- Single-end steam boilers consist of one to four furnaces, and these furnaces enter from the front end of the boiler.
#2. Double Ended Scotch Marine Boiler
Older double-ended Scotch Marine boilers typically had vertical Galloway tubes manufactured in the combustion chamber. They were meant to promote the circulation of water in the boiler and thus contribute to reducing stresses in the material.
- A double-ended steam boiler has a length of up to 6.5 meters.
- In double-end Scotch Marine boilers, the furnaces are present at both ends of them. And the numbers of furnaces vary from 2 to 4 at each end.
Parts of Scotch Marine Boiler:
The following are the important manufacturing parts of Scotch marine boilers:-
- Combustion chamber
- Boiler Shell
It is space above the Greater & below the boiler; it is employed to burn solid fuel inside the boiler. Single-ended boilers are fired with four furnaces. The furnaces are usually corrugated for strength.
In thises type of boiler, each furnace has its own combustion chambers. It is used to burn fuel inside the boiler. A single-ended Scotch marine boiler is fired with four furnaces.
The furnaces are usually corrugated for strength. Each furnace has its own combustion chamber.
#2. Combustion chamber
This is the space, usually below the boiler shell, to burn fuel so that water kept in the shell can generate steam. The combustion chamber consists of a fine plate, which needs to be in place, i.e., the top plate, the backplate, two side plates, and the tube plate.
It is a part of the boiler where fuel combustion takes place. The combustion chamber consists of fine plates, which need to remain, i.e., the top plate, backplate, two side plates, and tube plates.
There are several horizontally placed smoke taps that connect the combustion chamber to the chimney.
#3. Smoke Box
The smokebox contains several smoking tubes that are placed horizontally and connect the combustion chamber to the chimney. The smoke passes through these smoking tubes and eventually enters the chimney. The smoke passes through these smoking tubes and eventually enters the chimney.
The chimney is used to expel fumes and burnt gases from the boiler. The gases that flow through the chimney are released into the atmosphere. It is used to flush out the smoke and burnt gases from the boiler. Exhaust gases are released into the environment through the chimney.
#5. Boiler Shell
The boiler shell is made of a steel plate. This protects the internal parts of the boiler. All important fittings of the boiler are fitted on the boiler shell. It is made of steel plates bent in a cylindrical form and rinse or welded together. The boiler shell must have sufficient capacity to contain water and steam.
It protects the interiors of the boiler. All the necessary fittings of the boiler are adjusted on the shell of the boiler.
Working of Scotch Marine Boiler:
The fuels are injected into the furnace through a fire hole. The fuel in the furnace is ignited through a fire hole. The burnt fuel enters the combustion chamber. Fuel combustion takes place here.
The heat generated in combustion chambers is used to heat the water around the combustion chamber. Water is converted into steam, and it is supplied to the steam turbine. The exhaust gases after combustion pass through the smoke tubes and reach the chimney.
The chimney releases these fumes and exhaust gases into the atmosphere. It has a drum of diameter from 2–5 to 3–5 m which is placed horizontally. These steam boilers can be single-ended or double-ended. Single steam boilers can have lengths of up to 3–5 meters, while those for double-ends can be up to 6–5 meters.
A single-ended boiler consists of one to four furnaces that enter from the front end of the boiler. A double-end boiler has furnaces at both ends and may have two to four furnaces at each end. Single-ended boilers are fired by four furnaces, as shown in the figure.
The furnaces are usually corrugated for strength. Each furnace has its own combustion chamber. The combustion chamber consists of a fine flat plate that needs to be in place, i.e., the top plate, backplate, two side plates, & the tube plate.
There are several horizontally placed smoke taps & that connect the combustion chamber to the chimney. The front & backplates of the shell are reinforced by longitudinal occupancy.
The wall of the combustion chamber is from the best heating surface. The furnace tube, smoke tube, and combustion chamber, all being surrounded by water, give a very large heatings surface area in proportion to the cubical size of the boiler.
The water seeps around the smokebox. The water level remains slightly above the combustion chambers. Flue gas from the combustion chamber is drafted through the smoke tubes, and finally, the chimney is lifted up. Smokeboxes are provided with a gate for cleaning tubes and smokeboxes.
- Fuel is burnt at the furnace, and hot burnt gases are produced. This hot burnt gas enters the combustion chamber. A large amount of heat is produced in the combustion chamber. The heat from the combustion chamber is used to heat the water surrounding it.
- The waters are converted into steam, & the steam is passed onto the turbine.
- The water surrounds the furnace, combustion chamber, and smoke tubes, and because of this, the Scotch Marine boiler provides a more heated surface for water.
- Burned exhaust gas travels from the smoke tubes to the chimney.
- The chimney releases these exhaust gases or fumes into the atmosphere.
- In this boiler, the water level is maintained slightly above the combustion chamber.
Advantages of Scotch Marine Boiler:
Here, the different Advantages of the scotch marine boiler are as follows
- It is small in size.
- Boilers have the ability to operate any type of water.
- It has the ability to work in any type of water.
- This boiler does not require a brickwork setting and external flex.
- This boiler has considerable efficiency in operation.
- This boiler does not require a brickwork setting and external flues.
Application of Scotch Marine Boiler:
Here, the different Applications of the scotch marine boiler are as follows
- These boilers are commonly used in marine works and ships.
- This is due to its compactness, efficiency in operation, and its ability to operate in any kind of water.
- These boilers are commonly used in marine works. The reason for this is its compactness, efficiency in operation, and ability to operate in any type of water.
- This boiler is used on ships.
Disadvantages of Scotch Marine Boiler:
Here, the different Disadvantages of the scotch marine boiler are as follows
- More floors area are required for a given output.
- Load variations cannot be easily controlled.
- It is used in small power plants.
- The rate of steam formation & steam quality is not much better than water tube boilers for suitable power generation.
Frequently Asked Questions (FAQ)
Scotch Marine Boiler
Our two-pass, three-pass or four-pass Scotch Marine(Fire Tube) boilers are available in dry back, wetback, steam, or hot water versions; from 15 to 800 hp with pressures to 300 PSIG. Hurst Scotch Marine boilers are rated to 81% minimum efficiency.
Scotch Marine Boiler Working
Water is surrounded by the tube. The heat generated is much high and due to that, even the tube gets hot. Due to the heated tubes, the water starts getting heated and its phase is 1st water to saturated steam and saturated steam to superheated steam.