What is a boiler Draught?

Boiler draught is defined as the difference between absolute gas pressure at any point in a flow passage and the ambient (same elevation) atmospheric pressure. Draught is achieved a small pressure difference which causes the flow of air or gas to take place. It is measured in millimetre (mm) or water.

What is the purpose of a Draught?

Mechanical draught is preferred for central power stations. In a forced draught system, a blower is installed near the base of the boiler and air is forced to pass through the furnace, flues, economizer, air-preheater and to the stack.

Why boiler draft is essential in steam boiler?

They reduce the pressures inside their bases so that the greater pressure of the atmos- phere outside pushes air through the fuel bed and gases of combustion through the boilers into their bases.

What is a natural Draught boiler?

A natural draft furnace is one that uses natural atmospheric pressure to force the waste gasses of combustion out through the ventilation system. Hot air naturally rises, lifting the combustion byproducts along with it.

What is Draught and types?

Draught is defined as the difference between absolute gas pressure at any point in a gas flow passage and the ambient (same elevation) atmospheric pressure.

What is the necessity of producing Draught in a boiler?

Draught in a boiler is defined as the small difference in pressure between outside cold atmospheric air and that of gases inside the chimney. This is necessary to force air through the fuel grate for combustion as well as for exhausting combustion gases in the chamber.

What is boiler Draught or draft?

The difference between atmospheric pressure and the pressure existing in the furnace or flue gas passage of a boiler is termed as draft. Draft can also be referred to as the difference in pressure in the combustion chamber area which results in the motion of the flue gases and the air flow.

What is the main principle of draft tube?

The draft tube is a conduit which connects the runner exit to the tail race where the water is being finally discharged from the turbine. The primary function of the draft tube is to reduce the velocity of the discharged water to minimize the loss of kinetic energy at the outlet.

Why boiler draft is important?

Importance/significance A boiler equipped with a combustion chamber which has a strong current of air (draft) through the fuel bed will increase the rate of combustion (which is the efficient utilization of fuel with minimum waste of unused fuel).

What is balanced Draught?

The balanced draught is a combination of forced and induced draught. The forced draught overcomes the resistance of the fuel bed there fore sufficient air is supplied to the fuel bed for proper and complete combustion.

What is Draught system?

7.1 INTRODUCTION TO DRAUGHT SYSTEM Boiler draught is the pressure difference required to maintain constant flow of air into the furnace and to discharge the flue gases to the atmosphere through a chimney. Thus, boiler draught is one of the most essential systems of a thermal plant.

What is Draught and its types?

What is boiler draught and why is it important?

Boiler draught may be defined as the small difference between the pressure of outside air and that of gases within a furnace or chimney at the grate level, which causes flow of air/hot flue gases to take place through the boiler.

What is the draught in a thermal power plant?

The draught is one of the most essential systems of the thermal power plant which support the required quantity of air for combustion and removes the burnt products from the system. To move the ait through the fuel bed and to produce a flow of hot gases through the boiler economiser, preheater and chimney require a difference of pressure.

How does a forced draught system work?

In a forced draught system, a blower is installed near the base of the boiler. This draught system is known as positive draught system or forced draught system because the pressure of air throughout the system is above atmospheric pressure and air is forced to flow through the system.

What is a steam jet draught arrangement in a boiler?

The jet of steam is turned into a smoke box or chimney. The kinetic head of the steam is high but static head is low i.e., it produces a partial vacuum which brings the air through the grate, ash pit, flues and then to motor box and chimney. This type of induced steam jet draught arrangement is used in locomotive boilers.