Boiler Centrifugal Draft | Draught Exhaust Fan | Air Blower Specifications Y5-48 Series

The Y5-48 centrifugal induced draught fan for boiler is designed for burning various fuels and 1t/h~20t/h industrial boiler provided with smoke prevention and dust control unit, it may be selected to use when every inlet condition is the same and performance is the similar, but the maximum temperature shall normally not exceed 250℃.
Product description

PURPOSE
The Y5-48 centrifugal induced draught fan for boiler is designed for burning various fuels and 1t/h~20t/h industrial boiler provided with smoke prevention and dust control unit, it may be selected to use when every inlet condition is the same and performance is the similar, but 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,the efficiency of the added dust remover is not less than 85%.


TYPE
1. The fan is made as a single suction. There are 6 types of fan numbers which are 4, 5, 6.3, 8, 10 and 12.5.
2. The fan can be made of 2 types of rotation i.e, right and left. Viewing from one end of the motor, it is called as clock-wise fan if the impeller rotates clock-wise, symbolized with "right", On the contrary, it is called as counter-clock-wise fan if the impeller rotates counter-clockwise, symbolized with "left".
3. The outlet position of the fan can be expressed from the outlet angle of the casing. It can be made 6 kinds of angles which are 0°, 45°,90°, 135°,180°,225°,from both "Right" and "left".


STRUCTURE
Industrial boilers series at present are so many, great disparity on quality for combustion coal, resistance of dust catcher used is different, air quantity and air pressure required for draught fan is greatly different. To suit to the above situation, consider the economy of the fan, use belt (type C) gear, thus it can not only satisfy the requirements for varied dust catchers collocated for same tonnage boilers by one machine NO. with different speed as a result fan series and machine No. is reduced, but also convenient for user to choose different speed acc. to actual situation to obtain the air quantity and air pressure required.
The series fan consists of impeller, casing, inlet, damper and driving unit, etc.:
Impeller — 12 backward-plate blades ,the material is 16 Mn, welded between the circular conic cover and flat disc, will guarantee a smooth running after being static and dynamic balanced. With higher strength,vibration abrasion resistance and prolong service life.
Casing — To be welded into a volute with normal steel plate. Above No.8 "Left" and "Right" rotation are in common use. Dust cleaning gate is provided on the scroll plate in order to remove the dust deposit on the vane and in the enclosure so as to ensure the balance of impeller and pneumatic performance.
Inlet — To be integrated into a convergent streamlined structure and bolted on the suction side of the casing.
Damper — Regulating gate is petal shape, №4~6.3 is 9 pieces and №8 above is 11 pieces, axially installed in front of air inlet, because of external drive mode to be used, drive is agile and convenient. Regulating range is from 0°(full opening)to 90°(full closing). Handle position of the regulating gate is at right side looking from air inlet. For "right-hand" fan, the handle is from full closing to full opening by pushing from lower to upper. For "left-hand" fan. Handle is from full closing to full opening by pulling from upper to lower. To make all parts of regulating gate mnormal operation, lubrication must be good. Molybdenum disulfide high temperature (260℃) grease must be used for lubrication.
Driving unit — Consist of mainshaft, bearing box and pulley. Mainshaft is made from high quality steel, with rolling bearing and water cooling integral bearing box, therefore, water supply pipe must be additionally installed, water consumption is varies with ambient temperature, generally consider by 0.5~1m3/h. bearing box is provided with thermometer and oil level indicator, luboil is 30# machine oil, oil filling capacity is carried out acc. to oil level mark.


PERFORMANCE AND SELECTION
This catalog gives only the nondimensional performance table and curve of the №10 samply machine, by which the dimensional performance of the fan of №10 and above can be calculated.
The dimensional performance curve is converted with non-dimensional performance curve. The converting formula is as follows:

11.jpg


Where:
Q — Flow(m3/h)
Kp — Full pressure compression coefficient
P  — Total pressure(Pa)
Nin  — Inner efficiency(kW)
D2   — Diameter of outside end of impeller blade(m)
Nre  — Req. power (kW)
U2   — Line speed of outside end of impeller blade(m/s)
ηm  — Mechanical efficiency takes 0.95(belt drive)
ρ1   — Air intake density(kg/m3
K  — Motor power storing factor,take 1.3


Generally, the performance of the fan indicates the performance of feeding air at appointed state. Appointed state of the Y5-48№4C~6.3C is: atmospheric pressure Pa=101325Pa, medium is smoke, air temperature t=140℃, air density ρ=0.85kg/m3. performance table of the fan with regulating gate indicates such parameters as vane of regulating gate is full opening (0°).


When service condition is not consistent with the appointed state, the performance at the non-appointed state must be converted to ones at appointed state, the conversion formula is:

22.jpg


Where:ηin — Inner effic  n — Speed(r/min) ρ — Air intake density(kg/m3
With footnote 0 symbolizes the standard state,without footnote 0 symbolizes the service state.


Table 1 Nondimensional performance table of Y5-48 №10 sample machine


1

2

3

4

5

6

7

φ

ψ

ψd

λ

ηin

0.0835
0.585
0.0185
0.0649
0.753

0.0975
0.579
0.0252
0.0711
0.794

0.1115
0.562
0.0330
0.0762
0.822

0.1255
0.536
0.0419
0.0806
0.835

0.1395
0.500
0.0519
0.0841
0.829

0.1535
0.450
0.0632
0.0860
0.803

0.1675
0.388
0.0758
0.0863
0.753


33(001).jpg

Fig.1 Nondimensional performance curve of Y5-48№10 sample machine

Fig.2 Regulating performance curve of Y5-48№10 sample machine


During operation, excessive or lack flow rate is often existed. The reasons are many ones. If this phenomenon occurs during the operation, the reason may be that the drag in the pipeline is great sometime or small sometime. If the drag is successively reduced for a long time during operating or the drag is suddenly reduced in a short time, it may mainly be the pipeline to be plugged. When a fan is installed and excessive or lack flow rate is occurred during normal running ,the reasons have mainly two aspects:

 
1. The actual and theoretic values k of resistance in pipe net is widely different. It was known normal pipe net characteristic equation: P=KQ2, if the actual value k is less than the theoretic value k, the flow rate increases; vice versa, flow rate decreases, see Fig.3.

44(001).jpg

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


2. The effect of fan total pressure deviation △p have not been considered during selecting. when the actual total pressure of fan is a positive deviation, the flow rate increases, and when it is a 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:
a. Flow rate can be adjusted by damper opening and closing.
b. Flow rate can be adjusted by changing the speed of the fan.
c. Flow rate can be adjusted by changing a higher or lower pressure fan.
d. Flow rate can be adjusted by changing pipe net resistance, and using 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, at this moment, the damper has lost its function, so try to reduce the resistance coefficient of pipe net, or increase the speed of the fan, or change-over a higher pressure fan, but the fan driven by motor and coupling can not be normally changed the speed, only the fan driven by belt, the speed can be increased and decreased by the means of changing the size of belt pulley diameter, the max. speed must be lower than that listed in the performance table, and the motor power shall be calculated.


SUPPLY SCOPE OF FAN UNIT
One fan, one regulating gate, one mating motor, a pair(two sets) of motor slide rail, a set of foundation bolts ( 4 sets for №4~6.3 and 8 sets for №8 and above), one motor pulley and a pair of triangle belt.


PURCHASE INFORJMATION
When purchasing, indicate the fan size, flow rate, pressure ,discharge angle, rotation direction and the motor model, power and speed etc.
If any one of technical parameters and indices regarding our existing machine No., air outlet angle and drive mode can not satisfy your production requirement, we have the capability to rebuild or redesign for you until you are satisfied.



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