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A forced draught is where the air flow comes directly from the fan to the object. Such as an hair dryer.
An induced draught is where the air flow is induced {lit lead in} by a separate flow of air. For example, an abrasive jet would quickly wear out if the abrasive passed through the jet nozzle. the flow of abrasive is added (induced) into the air flow by a jet of clean air.
If an air flow is corrosive or very dirty then an induced flow system would be appropriate.
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Is forced draft has negative pressure drop?
No, the forced draft fan has positive pressure as it just forces yhe air into the combustion chamber.only the induced draft fan has negative pressureas it removes the flue gases & exhaust gases is stacked up
What is forced ventilation?
A fan is used
How FD and ID fan control the air flow?
FD or Forced Draft Fans supply combustion air to the boiler. Different combustion controls demand a supply of combustion air in different ways but what they have in common they control the FD fan to provide enough air for complete combustion in the boiler furnace. In most systems in use today the ID or Induced Draft fan sucks the products of combustion from the boiler furnace, through the various passes of the boiler and pushes it out the chimney. How much or how fast this fan works is based on furnace pressure. The ID fan control set point is based on combustion side furnace pressure. If the furnace pressure goes up the ID fan removes more air to lower the pressure. As the furnace pressure goes down the ID fan removes less air. This air flow out of the boiler is referred to as draft. Both the FD and ID can be controlled by various means. The air flow can be restricted in the plenum or ducts by dampers or louvers or the speed of the fan can be changed by mechanical means from a fixed speed driver. Also the speed of the fan can be changed by the use of a variable steam turbine or an electric motor with VFD (Variable Frequency Drive)
What type of load is used in celling fan and table fan?
indutive
What makes of fan can be used for cooling and heating?
The most notable fan used for both heating and cooling would probably be of the Dyson brand. They have a product called the Dyson Hot+Cold, which is a bladeless heater fan used for both cooling and heating.
Why induced draft fan capacity is more compare to forced draft fan in power plant?
Because it is induced
Is forced draft has negative pressure drop?
No, the forced draft fan has positive pressure as it just forces yhe air into the combustion chamber.only the induced draft fan has negative pressureas it removes the flue gases & exhaust gases is stacked up
Forced draft fan vs induced draft fan?
In a balanced draft boiler, you actually have both: forced draft (FD) fans supplying air to the furnace, and induced draft (ID) fans removing flue gas. Typically, the FD fans control airflow, while ID Fans control furnace pressure to slightly below atmospheric pressure. In general though, the choice between forced draft and induced draft is based on how "tight" the system is - if you have leaks, it is better to use ID, as FD will cause product loss.
How induced draft fan works?
flue gas out
Why induced draft fan operate first instead of a forced draft fan?
The procedure for starting draft plant (fans) in a boiler is to start the ID Fan first. Remember that the purpose of the ID Fan is so that the Furnace operates at a slight vacuum. (See Related Link: FD Fan vs ID Fan.) Any casing or furnace leaks then allow air to leak in, rather than allowing air with pulverised fuel and fly ask to leak out.
What is the difference between induced and forced draft cooling tower?
Induced draft --- A mechanical draft tower with a fan at the discharge (at the top) which pulls air up through the tower. The fan induces hot moist air out the discharge. This produces low entering and high exiting air velocities, reducing the possibility of recirculation in which discharged air flows back into the air intake. This fan/fin arrangement is also known as draw-through. (see Image 3)Forced draft --- A mechanical draft tower with a blower type fan at the intake. The fan forces air into the tower, creating high entering and low exiting air velocities. The low exiting velocity is much more susceptible to recirculation. With the fan on the air intake, the fan is more susceptible to complications due to freezing conditions. Another disadvantage is that a forced draft design typically requires more motor horsepower than an equivalent induced draft design. The benefit of the forced draft design is its ability to work with high static pressure. Such setups can be installed in more-confined spaces and even in some indoor situations. This fan/fill geometry is also known as blow-through.
What is the function of forced draft fan?
force draft fan is helped in producing draft. therefore, no requirement of more chimney height. with the help of forced draft we would rapidly circulated the air from boiler to chimney. this fan is mounted near the boiler bottom.
What is the pressure at the discharge side of a forced draft fan is?
nagitive
What is an induced-draft air-cooled condenser?
relies on natural convection and doesn't use a fan
What is a balanced draft and how is it controlled?
furnace equipped with FD(force draft) and ID(induced draft) fan /blower are called balanced draft system.Fd used to regulate combustion airflow while ID used to regulate furnace pressures type of furnace operate slightly below ATM pressure .
During the defrost cycle of a forced draft low temperature evaporator the evaporator fan would what?
during the defrost cycle of a forced draft low temperature evaporator, the evaporator fan would?
Why cant you use a forced draft fan in place of induced draft fan?
It can be used, however not on the same piece of equipment. A forced draft fan is typically much smaller than an induced draft fan. A FD fan moves cooler air into the combustion zone while the ID fan removes the products of combustion from that zone. Typically the volume of gasses the ID Fan needs to remove is from 125% to 200% more than that of the FD fan. example: an FD fan moves 20,000 scfm of air at 100 *F, what size ID fan do you need if the exhaust gasses are 450 *F and the products of combustion and moisture add 3500 cfm to the volume of gasses? PV/T = P'V'/T' with pressure being negligible (it usually isn't) the formula is then : V/T = V'/T' to get the volume needed for the ID fan then: VT'/T = V' V = 20,000 scfm, T = 560 *R (absolute zero scale) and T' = 910 *R 20,000 scfm x 910*R/560*R = 20,000 scfm x 1.625 = 32,500 scfm thus, the ID fan must be sized at least 62.5% larger than the FD fan.
