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Single suction centrifugal fan

key word:Heat exchange element

Category:


Product description

Single suction centrifugal fan

 

1. Introduction

1.1. Application

1.1.1. It is suitable for the ventilation system of boilers in thermal power plants, as well as in mines, metallurgy and other industries. The conveying medium is air.

1.1.2 when it is used for induced draft fan, the inlet temperature is generally about 140℃ (allowable ≤ 250℃ in a short time). According to JB4358-2008 "Centrifugal Fans for Power Plant Boilers", dust removal devices should be installed upstream, and the dust concentration of flue gas entering the fan should not exceed 200mg/m3.

1.2. Model meaning

G 4-73 - 12 No25 F

G -- Code of forced draft fan

4-73 --- 4 is the reduced integer of total pressure coefficient multiplied by 10 at the highest efficiency; 73 is the value of specific speed at the highest efficiency of single suction air inlet mode (existing series of 4-59, 4-60, 4-73, 4-78, 4-80, 5-47, 5-48, 6-45, 8-30, 9-19, etc.)

12 -- Design serial number

No25 -- fan number, i.e. impeller diameter (dm)

F --- F is double support coupling transmission mode; D is cantilever support coupling transmission mode

1.3. Structural features

1.3.1. This series of fans are single side suction type, mainly composed of impeller, casing, collector, air inlet box, regulator and transmission part. The impeller is made of low alloy steel plate by welding, and the special impeller is made of high strength alloy steel; the casing is welded by ordinary steel plate and regional wear-resistant lining plate, so as to improve the service life.

1.3.2. 4-59, 4-73, 4-80, 5-48 series fan impellers adopt wing type blades, which have the advantages of high efficiency, low noise and high structural stiffness; the other series of fan impellers adopt backward plate blades, which are safe, wear-resistant and low manufacturing cost.

1.3.3. The casing and inlet box are of open structure, which are convenient for transportation, installation, maintenance and vertical lifting of impeller rotor. A manhole door is set in the middle of the casing to facilitate inspection and cleaning in and out, and a drain valve is set at the bottom.

1.3.4. The bearing pedestal is equipped with circulating cooling water channel, which is cooled by industrial circulating water, with water pressure of 0.2 ~ 0.4MPa and water volume of 0.5 ~ 1.0t/h; in addition, the bearing pedestal is also equipped with bimetal thermometer and remote platinum thermal resistance temperature sensing element.

1.3.5. The dynamic balance and overspeed test shall be conducted before the impeller leaves the factory.

1.4. Working principle

Start the motor and drive the impeller to rotate to do work through the coupling. The gas is sucked into the impeller by the inlet box and then turned 90 ° to flow through the impeller blade to obtain energy, that is, the static pressure increases and the kinetic energy increases. The casing collects the gas thrown out by the impeller, converts part of the kinetic energy into static pressure energy after diversion and pressure expansion, and then discharges from the outlet for the system needs.

1.5. Product series

The impeller diameter of single suction single support and cantilever centrifugal fan series is 1.2 ~ 4m. The manufacturer can select the best model and machine number according to the parameters provided by users.

 

2. Main technical parameters

The user shall provide the following technical parameters:

2.1. Unit capacity.

2.2. Type of fan application.

2.3. Local atmospheric pressure (Pa).

2.4. Local altitude (m).

2.5. Fan operating parameters under various working conditions:

2.5.1. Boiler load (%).

2.5.2. Mass flow rate (kg/s).

2.5.3. Standard flow rate (m3/s).

2.5.4. Fan inlet flow (m3/s).

2.5.5. Fan inlet temperature (℃).

2.5.6. Fan outlet temperature (℃).

2.5.7. Standard density of state (kg/m3).

2.5.8. Fan inlet density (kg/m3).

2.5.9. Static pressure at fan inlet (Pa).

2.5.10. Static pressure rise (Pa).

2.5.11. Muffler loss (Pa).

2.5.12. Total pressure rise (Pa).

2.6. Motor requirements and power supply voltage.

 

3. Equipment appearance and structure

The structure of single suction centrifugal fan is shown in Fig. 13-1 and Fig. 13-2.

 

4. Selection method

Generally, the manufacturer can select the type of microcomputer according to the specifications according to the parameters provided by the user. The following simplified formula chart method can also be used for rough selection:

4.1. Convert the parameters provided by users to standard inlet conditions. The standard inlet condition of forced draft fan is: atmospheric pressure pa = 101325 Pa, inlet air temperature is 20 ℃, gas density is 1.2kg/m3, conversion formula is

Full pressure       

                                 

Flow   q0 = q (m3/h)                   

Where       p0, q0, ρ0, t0 -- pressure, flow rate, density and temperature under standard inlet conditions;

p, q, ρ, t ----- pressure, flow rate, density and temperature of the fan under service conditions;

Pa standard atmospheric pressure;

Pb local atmospheric pressure.

4.2. Calculate the specific speed. The calculation formulas of specific speed are as follows

Specific speed of single stage single suction blower     

 

Specific speed of single stage double suction blower    

4.3. According to the specific speed value, select the similar series of fans, and then according to the logarithmic coordinate curve of the series of fans (see Fig. 13-3 ~ Fig. 13-6), obtain the speed and fan model meeting the required flow and pressure conditions, and check with the fan performance parameters.

The selection curve is shown in Fig. 13-3 ~ Fig. 13-6.

 

5. Scope of supply

5.1. Scope of complete set of supply included in the price of each fan

5.1.1. Fan body (including impeller rotor, bearing seat, machine light, collector, regulator, air inlet box).

5.1.2. Coupling and guard 1 set.

5.1.3. One set of anchor bolt.

5.1.4. Two PT100 platinum thermistors and two bimetallic thermometers were observed on site.

5.2. Order items that can be added according to the user's requirements (ordering for the user or supporting supply, the price is calculated separately)

5.2.1. Motor.

5.2.1. Electric actuator (for guide vane adjustment).

5.2.2. Vibration monitoring device is used for rotor vibration monitoring and alarm. It is basically equipped with one horizontal and one axial sensor for each fan, and each instrument monitors two fans.

5.2.3. Local junction box (or instrument box, including digital display meter).

5.2.4. Non metallic expansion joint at inlet and outlet.

5.2.5. Muffler (for forced draft fan and secondary air fan).

5.3. Technical documents provided during supply

5.3.1. Shipping list.

5.3.2. Operation instructions (with general installation drawing, main bearing assembly drawing, etc.).