Ideal Classic Boiler | Furnace Room Air Combustion Ventilation Exhaust Fan Types GY4-73 Series

Ideal Classic Boiler | Furnace Room Air Combustion Ventilation Exhaust Fan Types GY4-73 Series

Type G4-73 and Y4-73 forced and induced draught fan for boiler are mainly used for 2~670 t/h steam boiler in thermal power station.Type G4-73 may be also used for mine ventilation and general ventilation without special requirement.
Product description

PURPOSE OF THE FAN
Type G4-73 and Y4-73 forced and induced draught fan for boiler are mainly used for 2~670 t/h steam boiler in thermal power station.Type G4-73 may be also used for mine ventilation and general ventilation without special requirement.
The medium which is handled by fan is air,the maximum temperature shall normally not exceed 80℃;the medium handled by induced draft fan is flue gas,the maximum temperature shall normally not exceed 250℃.
The dust control unit must be added in the front of induced draft fan in order to reduce the dust content of flue gas entered the fan.According to the operation condition in the general power station,the efficiency of the added dust remover is not less than 85%.

 

TYPE OF FAN
1. The induced draft fan is made as a single suction and there are 13 types of fan numbers which are №8~29.5
2. Viewing from the motor end,if the impeller rotates in clockwise,it is called a right rotating fan and symbolized with"right",on the contrary,if the impeller rotates in counter clockwise,it is called a counter clockwise fan and symbolized with"left".
3. The outlet position of the fan can be expressed from the outlet angle of the casing.
4.The driving mode of the fan takes mode D,the connection of flexible coupling is used.


STRUCTURE OF THE FAN
The fan mainly consists of impeller,casing,inlet,damper and driving unit:
1.Impeller — 12 backward wing blades welded between the circular conic cover and flat disc.Because of using the wing blades,high efficiency,low noise,high strength is guaranteed the impeller shall be balanced statically and dynamically,over speed running test is carried out,and thus it has smooth running. For the fan and induced draft fan impeller of the same fan №,the structure is the same,but the material is not the same,the fan generally selects A3,and the induced draft fan selects 16 Mn.


2.Casing — To be welded into a volute with normal steel plate. single suction fan casing is made three kinds of different types.(№8~12 casing is made in integral type,it can not be disintegrated,№14~16 casing is made in two-open type,№18~29.5 casing is made in three-open type)For the induced draft fan, the thicker voluted plate is used in order to prevent wear-out.


3.Inlet — To be integrated into a convergent streamlined structure and bolted on the suction side of the casing.


4.Damper — The unit which used to adjust flow rate is axially installed in the front of the inlet.Adjusting range is from 0°(full open) to 90°(full close).The handle position of damper is at the right-hand,viewing from the inlet side. For"Right" rotating fan,the handle from down to up is from full close to full open direction; for"Left"rotating fan,the handle from up to down is from full close to full open direction.


5.Driving unit — The main shaft of driving part is made of super steel,the fan takes rolling bearings.There are two kinds of types of bearing box: The integral barrel bearing box is used for №8~16; two independent pillow bearing boxes are used for №18~29.5.There are thermometer and oil indicator on the bearing box (only for the induced draft fan).30# mechanical oil is used for lubrication,the quantities of filling oil should be according to the requirement of oil level mark.If the integral barrel bearing box use dry oil,oil-catch plate should be added at the ball side in the bearing box,its fixed slots have been precasted.The induced draft fan has cooling water unit,thus,conveyance pipe should be added,the water consumption is a function of the temperature,normally 0.5~1m3/h is considered.

 

PERFORMANCE AND SELECTION OF FAN

00(001).jpg


Fig.1 non-dimensional performance curve of Type GY4-73

Fig.2 Adjust performance curve of Type GY4-73 №10


Type GY4-73 Fan only gives the non-dimensional performance table and curves of № 10 sample fan.The dimensional performance of №8~28 fan can be calculated with given non-dimensional performance table or curves.


The dimensional parameter formula is calculated with non-dimensional parameter:

11.jpg


Where:

P - total pressure (Pa)
Kp - total pressure compressibility factor
Q - flow (m3/h)
D2 - outside diameter of impeller blade end (m)
U2 - line speed of outside end of impeller blade (m/s)
ρ1 - density of inlet gas (kg/m3
Pin - inner power (kW)
Pre - required power (kW)
ηm - mechanical efficiency ( takes 0.98 for driving mode D)
K - storing factor of motor power,the fan takes 1.15,the induced draft fan take s 1.3


Non-dimensional performance table of Type GY4-73 №10 sample fan

 

1

2

3

4

5

6

7

8

Φ

0.147

0.166

0.186

0.205

0.224

0.243

0.263

0.282

ψ

0.472

0.470

0.465

0.453

0.432

0.403

0.362

0.315

ψd

0.0193

0.0246

0.0309

0.0375

0.0448

0.0528

0.0619

0.0712

λ

0.0874

0.0938

0.1009

0.1067

0.1115

0.1144

0.115

0.1119

ηin

0.794

0.832

0.857

0.87

0.868

0.856

0.828

0.794

22(001).jpg

Fig.3 The relationship between pipe net characteristic and total pressure deviation or flow rate


Treatment of the flow rate excess or insufficient:
The phenomenon of flow excess or insufficient often occurs when use,there are many reasons of occurring such phenomenon.If the phenomenon of flow some times large and sometimes small occurs during,the main reason is due to resistance in pipe net sometimes great and or sometimes small.If it is gradually reduced through longer time or suddenly reduced within short time,the main reason is that the fan passage or pipe net is plugged.


The phenomenon of flow excess or insufficient will occur during normal running after newly installing,the main reasons are as follows:
(1)The actual and calculated values of pipe net resistance is widely different. It was known normal pipe net characteristic equation p=kQ2 (k is the coefficient of resistance),if the actual value k is less than the calculated value k,the flow rate increases; vice versa, flow rate decreases.
(2)The effect of fan total pressure deviation △p have not been considered during selecting,when the actual total pressure of fan is positive deviation,the flow rate increases,and when it is negative deviation,the flow rate decreases.


The flow rate excess or in sufficient occurred after fan newly installing and when putting into operation,one of the following methods can be used to eliminate:
(1)Flow rate can be adjusted by damper opening and closing.
(2)Flow rate can be adjusted by changing the speed of the fan.
(3)Flow rate can be adjusted by changing a higher or lower pressure fan.
(4)Flow rate can be adjusted by changing the resistance coefficient of pipe net.


It must be pointed out: flow rate is normally adjusted by damper, but when the actual flow rate is much greater than the required, it wastes power. If the condition permits reducing fan speed or change-over a lower pressure fan.


When the damper is full open,the flow rate is still insufficient,so try to change the resistance coefficient of pipe net,to increase flow rare or increase the speed of the fan,or change-over a higher pressure fan,but the maximum speed of the fan should not exceed the max.speed listed in the performance table.


The performance of the fan normally indicates that the performance of conveyance air under the standard state.The standard state of induced draft fan indicates atmospheric pressure Pa=101300Pa, atmospheric temperature t=200℃, air density ρ=0.745kg/m3, the performance in the table indicates the adjusting blades are full opened at 0°. Take the performance table as standard when ordering. 


If it is in standard state when operating,the performance of non-standard state must be converted to the performance of standard state.Then select fan according to the converted performance The converting formula is as follows:

33.jpg


Where:
n - speed (r/min)                       ηin - Inner efficiency
with footnote 0 means standard state, without foot note 0 means service state.

 

PURCHASE INFORMATION
When purchasing,indicate the fan size, speed, flow rate, pressure, discharge angle, rotation direction and the motor model and size.

Note: GY4-73№20F~31.5F,Y-4-2×73№28.5F,37F and Y4-73-14,see other operation instruction.


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