Simple Vertical Boiler, Construction, Working And List of Parts

Simple Vertical Boiler, Construction, and Working:

Simple Vertical Boiler

It consists of a cylindrical shell. This shell is usually placed in a vertical position. A popular boiler of this type has got the capacity of generating 300 kg of steam/hr. Its working pressure goes up to 10 bar. 

The main characteristics of this boiler are as under:

1. It is vertical.

2. It is portable with a very small floor area.

3. It is a water tube boiler.

4. It is a multi-tube boiler with two cross tubes.

5. It is internally fired.

6. It is naturally circulated.

7. It is a solid fuel-burning boiler.

8. It is a low-pressure boiler.

The list of Main Parts of Simple Vertical Boiler:

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1. Cylindrical shell
2. Tubes
3. Firebox
4. Grate
5. Ash pit
6. Fire hole
7. Water level and steam indicator

1. Cylindrical shell: In this shell, cross-tubes are arranged.

2. Tubes: These tubes are placed at an angle of 15 to 30 degrees with the horizontal axis.

3. Firebox: The firebox is provided at the bottom of the shell. This fire-box is fitted with a grate (a platform on which coal is placed and burnt).

4. Grate: The grate is made of a number of steel or C.I. bars. These bars are fixed in such a way that an air space is provided between bars. The air space will help the ashes produced by the combustion of coal or any other fuel to fell down.

5. Ash pit: An ash pit or ash pan is placed below the grate. The function of the ash pit is to collect the ashes.

6. Fire hole: A fire hole is provided on one side of the grate. The function of this fire

hole is to add the coal as and when needed.

7. Water level and steam indicator: A large portion of the shell is filled with water. The firebox is also surrounded by water. The quantity of water is quite substantial. The remaining portion of the shell contains steam. The firebox is provided with two cross-tubes. This increases the heating surface and circulation of water.

Working of Simple Vertical Boiler:

Feeding of water in the boiler is done through the feed check valve. The level of the water is adjusted by knowing the level of water from the water level indicator. Coal is added to the grate from the fire hole. The boiler is then fired. The hot gases produced by the combustion of coal moves upwards. These upward-moving gases come in contact with the inclined cross- tubes. The heat is transferred to the water inside the tubes. Because of the inclination of tubes, the circulation of water is in the boiler by natural circulation. The chimney is provided to exhaust the hot gases, because of the heat transfer the water in the boiler is converted into steam. This steam is collected to space provided in the boiler, above the water level. This steam is then taken out through the steam stop valve for use.

This type of boiler is very compact. It is easy to transport these types of boilers. The space requirement is very less and it does not require a heavy foundation.

The efficiency of the boiler:

Hot gases directly go to the chimney and since the heat transfer is less to the water the efficiency of this boiler is very low. In the ideal condition, it is 50 % approx.

Technical specifications:

Steam generation rate: 50 kg/hr to 100 kg/hr

Steam pressure: 2 bar to 10 bar

Drum diameter: 0.6 m to 2 m.

Drum height 1.2 m to 4 m

Heating surface area: 8 to 10 times the grate area.

Mountings and Accessories Used in Simple Vertical Boiler:

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• Feed check valve - To fill water into the boiler shell.
• Water level indicator - To know the level of water in the boiler.
• Pressure gauge - To indicate the pressure of steam inside the shell.
• Safety valve - For the safety of the boiler against excessive pressure.
• Steam stop valve - For taking the steam out of the boiler for further utilization.
• Man-hole - For workman to enter in the boiler for inspection, cleaning, and maintenance
• A chimney - To exhaust the burnt flue gases out of the boiler.
• Hand holes - For necessary cleaning of the tubes from time to time.
• Blow-off cock - For removing impurities and scale etc., present in water which collects at the bottom of the boiler and to empty the boiler when necessary.
• Fusible plug - To protect the boiler from overheating due to the low water level.

Advantages of Simple Vertical Boiler

The following are the advantages of a simple vertical boiler:

1.  The initial cost is low because of the less number of parts.

2.  The cost of maintenance is very low.

3.  The construction and working are simple.

4.  The installation and replacement of parts are easy.

5.  The space requirement is less.

Disadvantages:

1.  The vertical design of this boiler limits its work in many places.

2.  Steam production is limited.

3.  The impurities settle at the bottom and thus prevents the water from heating up.

Application of Simple Vertical Boiler:

The following are the application of a simple vertical boiler:

1.  It is mostly used for applications in railway locomotives, for example, a railway steam engine.

2.  Simple vertical boilers are employed in road vehicles such as steam wagons or steam lorry.

3.  The simple vertical boiler application in a steam tractor.

4.  The number of boats is particularly small which uses simple vertical boilers to power the engine.

5.  In some parts of the world ordinary vertical boilers are used in the steam donkey.

6.  Simple vertical boilers are also worked in steam cranes and steam shovels.

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