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Variax axial fan with adjustable moving blades

key word:Heat exchange element

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Product description

Variax axial fan with adjustable moving blade

 

1. Introduction

1.1. Purpose

In thermal power plant, Variax adjustable blade axial fan can be used in boiler forced draft fan, primary air fan, induced draft fan, booster fan and combined fan. The specific location of booster fan includes A-position booster fan, C-position booster fan and D-position booster fan, as shown in Figure 6-1.

The working environment of position a booster fan is exactly the same as that of boiler induced draft fan. The booster fan in this location has a lot of operation experience and high temperature, which can avoid the occurrence of corrosion, and the development of anti-wear technology for fly ash wear makes the fan not affected by wear to the greatest extent.

The C-position booster fan is located between the absorption tower of the desulfurization island and the flue gas reheater (GGH). The flue gas enters GGH through the c-position booster fan after coming out of the absorption tower of the desulfurization island. The temperature of the flue gas is between 45-50, which is highly corrosive. Although the power consumption of the c-position booster fan is the lowest, due to the harsh environment of the fan location, the maintenance cost is very high.

The D-position booster fan is located behind GGH, and the flue gas heated by the flue gas reheater is unsaturated flue gas; meanwhile, the fly ash has been removed in the absorption tower. The material of D-position booster fan is basically the same as that of A-position booster fan, but considering the lower flue gas temperature, the potential flue gas corrosion should also be considered.

1.2. Model meaning

The model and significance of Variax adjustable blade axial fan are as follows:

AN N(T) – 5120/ 2600 B(N) 590

AN -------- AN stands for axial flow. with enlarged inlet box; AS stands for axial flow, with standard inlet box

N (T) ---- impeller series (N-single stage; T-double stages)

5120 ------ impeller diameter (mm)

2600 ------ hub diameter (mm)

B (N) ---- wheel hub form

590 -- speed (r/min)

1.3. Product features

1.3.1. Overall structure. Variax adjustable blade axial fan has two forms: single-stage and double-stage. The structure is divided into two parts: rotating parts and static parts. Among them, the rotating parts mainly include hub, blade, petiole bearing, hydraulic regulating device, main bearing group and coupling; static parts include inlet box, impeller shell, middle air guide vane, diffuser, sliding support, hydraulic and lubricating oil station, heating element and sealing air system, as well as inlet and outlet expansion joints. Figure 6-2 shows a typical structure of a single-stage Variax adjustable blade axial fan.

 

1.3.2. Wide performance range. Variax axial fan with adjustable blades has a very wide range of aerodynamic performance. The flow range of single-stage axial flow fan is 25 ~ 1600 m3/s, and the pressure range is 300 ~ 14000 Pa; the flow range of double-stage axial-flow fan is 15 ~ 1600 m3/s, and the pressure range is 1500 ~ 28000 Pa. Such a wide performance coverage is due to the adoption of advanced flow channel design. The improved large-scale inlet box can ensure the smooth flow of air into the fan. The collector and the optimized front guide vane make the air flow into the moving blades of the fan evenly and produce certain pre swirl, so as to improve the pressure rise. As shown in Fig. 6-3, the best combination of the moving blade and the rear guide vane can minimize the loss when the airflow changes direction and enters the diffuser along the axial direction. The diffuser is designed to ensure that the dynamic pressure is converted into static pressure to the maximum extent. Variable blade adjustable axial-flow fan is designed with medium pressure, large flow, high-pressure, high-pressure + special pre rotation front guide vane and ultra-high-efficiency blade profile, 10 kinds of standard N-type hub, 12 kinds of B-type hub and 22 kinds of hub ratio, thus forming a large number of aerodynamic models. In addition, different blade profiles make it possible to meet the requirements of increasing aerodynamic performance by changing the blade profile without replacing other parts of the fan. For example, the SCR system needs to be added in the later stage of the power plant to improve the performance of the fan. At this time, it can only be realized by changing the blade profile, so it is convenient, fast and low cost. Figure 6-4 shows the performance curves of fans with different blade types.

1.3.3. Energy efficient products. Variax adjustable blade axial fan is a kind of high efficiency and energy saving fan:

1.3.3.1. The aerodynamic performance of the fan is verified by rigorous model tests, and all the aerodynamic model tests are carried out in the laboratory of Howden Denmark in accordance with AMCA802 standard. The standard requires that the minimum diameter of the model level is 900mm. The performance of the model level is equivalent to that of the full-size product, and the efficiency does not consider the size amplification effect. Therefore, the efficiency marked on the performance curve has a certain conservative amount.

1.3.3.2. The optimized large-size inlet box reduces the inlet velocity and the loss of the inlet air flow. From the aerodynamic performance test results, it can be seen that the efficiency of the fan can be increased by 2% with the optimized large-size inlet box (see Fig. 6-5).

1.3.3.3. The tip clearance of blade has great influence on the total pressure and efficiency of the fan. The blade top clearance of Howden axial fan is strict. The minimum can reach 1, which is guaranteed by the integral impeller shell with very good rigidity and high machining accuracy. Through the guarantee of the top clearance, the loss is reduced, and the efficiency can be increased by 0.5% ~ 1%. Figure 6-6 shows the performance test results with 1.1 and 2.9 tip clearance. Smaller tip clearance can improve pressure lift and efficiency.

1.3.3.4. As shown in Fig. 6-7, the surface of blade root and hub is spherical, and the connection between blade and hub has only one positioning key, with smooth surface, uniform clearance and small loss, which can improve the efficiency of fan by more than 1%.

Figure 6-7 fitting and installation relationship of spherical surface between blade root and hub (a) spherical surface fit: (b) installation relationship

The results of performance test curve show that, compared with the bolt connection between blade and hub of Variax adjustable blade axial-flow fan, the efficiency can be increased by 1% ~ 3% for fans of different sizes (see Figure 6-8).

1.3.3.5. Flexible and reliable rotor blade control system. The angle adjusting system of Variax movable blade axial flow fan is mainly composed of hydraulic oil station, electric actuator, connecting rod, regulating driving device, fork, rotary oil seal, hydraulic cylinder and support shaft. The main feature of the system is that the whole hydraulic control system ensures the flexible and reliable adjustment of moving blade and fast response.

1.3.3.5.1. The hydraulic regulating oil station and the lubricating oil station are separated independently, so as to avoid the mutual interference between the two oil systems with different functions, facilitate the control of each subsystem, and ensure the stable and reliable operation.

1.3.3.5.2. No matter whether the fan blade angle is adjusted or not, the hydraulic regulating oil station is always in operation; the continuously circulating hydraulic oil will remove the dirt and impurities of the hydraulic oil system through the filter, and take away the heat generated in the operation process, so as to ensure the service life of all components, especially the sealing parts, and the reliability and stability of the system.

1.3.3.5.3. The design of the whole regulation system and hydraulic cylinder is a follow-up mechanism, without lag, which can accurately adjust and control the angle of the moving blade of the fan.

1.3.3.5.4. The regulation system is also equipped with anti-interference measures, which can prevent misregulation due to electrical or other disturbances.

1.3.3.5.5. The response of the whole regulating system is very fast. At the same time, the whole stroke adjustment time is short, which can ensure the quick response of the blade control system to the boiler load demand and the stable operation of the boiler system.

1.3.3.5.6. The adjustment time of the whole stroke is determined by different hydraulic cylinder sizes, generally ranging from 7 to 25 s.

1.3.3.5.7. Working principle of hydraulic cylinder. The hydraulic cylinder is the key component of the rotor blade adjustment system; the hydraulic regulation system includes the hydraulic oil station and the hydraulic regulating device installed on the wheel hub (see Fig. 6-9).

The hydraulic adjustment device includes a stationary hydraulic cylinder 10 and a piston 11. The piston transmits the displacement to the blade through the adjusting disc 12, and the plunger of the hydraulic cylinder forms the shell of the regulating valve 6. The regulating valve, together with orifice 16 and slot 7, reduces the pressure of the oil pump to atmospheric pressure.


The hydraulic oil station transmits the hydraulic oil to the hydraulic cylinder with constant oil flow through the rotating oil seal 2. The regulating device can be used in the occasions with high ambient temperature through the cooling of cooler.

In the balanced position, the positions of the outer adjusting arm 13 and the regulating valve 6 are fixed, and the hydraulic cylinder is in the undisturbed equilibrium position, so that the forces (pressure × area) on both sides of piston 11 are equal.

If the blade needs to be opened, the external adjusting arm 13 should be adjusted to the appropriate position indicated by the angle index plate of the fan. At this time, the regulating valve 6 will shift to the "open" direction through the adjustment of the external adjusting arm, so as to increase the slot hole 7, thus reducing the pressure on the side with large area of piston 11 (yellow area), and make the plunger 11 move to the "open" side until it is again Reach the equilibrium position.

If the blade angle needs to be reduced, the external adjusting arm 13 is also adjusted to the blade angle to be set. When the regulating valve 6 moves to the "close" direction, the slot hole 7 is closed, so that the oil pressure on both sides of the piston 11 is equal. Due to the area difference between the two sides of the piston, the hydraulic cylinder will move towards the impeller until a new balance is reached.

During the whole adjustment process, the hydraulic cylinder moves continuously until a new balance position is established. The movement distance between piston 11 and control valve 6 is equal. In order to ensure the same moving speed in both directions, the hydraulic oil flows into the pressure chamber on the larger side of piston 11 through slot hole 15. When slot 7 is closed, slot 15 is opened.

Moving valve 6 will never reach the "full open" and "full close" positions. In the vicinity of the equilibrium point, the disturbance of the valve is very small, because a slight disturbance will cause the pressure in the pressure chamber on the impeller side of the piston to change, thus causing the piston to move.

Spring 8 eliminates the gap between outer adjusting arm 13 and valve 6. In order to counteract the force of spring 8 to servo motor, balance weight is specially used.

1.3.3.6. Special design of rotating parts. The development, design, manufacture and test verification of the rotating parts of Howden an series axial flow fans have the following main features:

1.3.3.6.1. In the design and development stage of rotating parts, after passing the model test and obtaining satisfactory aerodynamic performance, advanced design means should be adopted, such as simulating the actual working conditions for stress analysis and calculation; establishing finite element model to analyze the dynamic stress state and natural frequency under various modes; and; The dynamic stress and frequency response of the components can be obtained by strain test. All these technical means and test data can ensure that all parts of the fan, especially the rotating parts such as blade and hub, have been verified in the design and development stage, and have sufficient strength and stiffness. At the same time, the safety and reliability of the equipment operation can be ensured, laying a foundation for standardized design.

1.3.3.6.2. The design concept of rotating parts is standardized design to ensure the use of mature and verified technology and parts, which can make the rotating parts have good interchangeability and facilitate the preparation and maintenance of spare parts.

1.3.3.6.3. Specially designed hub, blade and petiole bearing: Hub: Variax adjustable rotor blade axial flow fan, two types of wheel teaching are designed, namely N-type hub and B-type hub. The purpose of the two different types of wheel hub is different. The N-type wheel hub is a nodular cast iron wheel hub, which is mainly used to deal with the clean air environment and carry the cast aluminum blade; the B-type wheel hub is a high-strength carbon steel welding structure, which can be used for carrying cast iron or steel blade in harsh working environment.

Blade: vario variable blade axial flow fan has medium pressure, large flow, high pressure, high pressure + special pre rotation front guide vane and ultra high pressure high efficiency blade profile to meet different performance requirements. The performance curve of different blade types is shown in Fig. 6-10. Blade materials include cast aluminum alloy and nodular cast iron; in addition, according to different special needs of users, for very harsh operating environment, we can also use stainless steel with hard chromium alloy layer wear head and blade surface with different coating measures to improve the wear life.

Petiole bearing: as shown in Figure 6-11, Variax The petiole bearing of adjustable blade axial fan adopts special design. The blade bearing does not have cage and uses large ball. At the same time, the number of ball bearings is increased. Therefore, not only the bearing capacity of bearing is improved, but also the bearing life is prolonged. The operation period is increased and the maintenance cost is reduced while the blade angle is adjusted during operation. The petiole bearing of type B hub adopts oil bath lubrication. The specially designed oil seal and oil cavity ensure the bearing lubrication and reliable operation.

1.3.3.7. Anti corrosion measures for rotating parts. For induced draft fan and booster fan, especially booster fan, in order to prevent possible corrosion of rotating parts, all fans dealing with flue gas medium are equipped with sealing air system to prevent flue gas from entering into diffuser inner sleeve, middle air guide sleeve inner sleeve or air inlet box to corrode rotating parts and bearing sets. The sealing air system can be supplied in a single set or in the form of one for use and one for standby.

Figure 6-12 shows the working principle of the seal air system. For induced draft fan, booster fan and other equipment, seal air system is a very small accessory equipment, but it plays an extraordinary important role. The induced draft fan, especially the booster fan, because the medium to be treated is sulfur-containing flue gas, and the temperature of the inner cylinder of the inlet box and the diffuser is much lower than that of the flue gas.

Therefore, the important function of the seal fan is to provide the air heated by the heater to the cylinder in the inlet box and the inner cylinder of the diffuser, and establish a pressure greater than 250Pa between the cylinder in the inlet box and the inner cylinder of the diffuser and the flow channel In this way, the flue gas can not enter into the inner cylinder from the flow passage, so as to prevent the sulfur-containing flue gas from invading the rotating parts, causing serious corrosion and final damage to the rotating parts (including hub, main bearing, hydraulic cylinder, rotary oil seal, adjusting drive device, coupling, etc.). Therefore, the correct operation and use of the sealing fan according to the regulations is not only the protection of the rotating parts of the induced draft fan and booster fan, but also the guarantee for the long-term, safe and reliable operation of the induced draft fan and booster fan. This is also the reason why the matching mode is that each fan has four sets (one for operation and one for standby at the inlet box side and one for use and one for standby at the diffuser side). Of course, sometimes according to the results of calculation, it may not be necessary to seal the fan at the inlet side.

1.3.3.8. Factory test verification. Before leaving the factory, each fan needs to carry out relevant test verification to ensure that all parts meet the relevant requirements before leaving the factory.

1.3.3.8.1. Loading test of main bearing set. As an integral part, in order to ensure that the technical indicators of the spindle meet the requirements of the specification after assembly, the loading test shall be carried out on the test bench before delivery (see Fig. 6-13). The requirements of the test are to simulate the radial load and axial load under the actual working conditions under the working speed. After running for 6 ~ 8h or after the bearing temperature rise is stable for 1h, the bearing temperature and vibration and other indicators are qualified After that, they can leave the factory.

1.3.3.8.2. Adjustment force test. As shown in Fig. 6-14, the wheel hub assembly and the whole set of blades shall be subject to the adjustment force test in the factory, and the test shall be carried out at the maximum speed to check whether the regulating force of the two full strokes of the blade from full close to full open and full open to full close is balanced and meets the specification requirements, and whether there is sufficient adjustment space in the hub during the adjustment process.

1.3.3.8.3. Static moment balance of blade. The hub assembly of Variax adjustable blade axial-flow fan is separately dynamically balanced, and no blade is installed when the hub is in dynamic balance. Each blade has its own identification number, as shown in Figure 6-15. The static moment of each blade is weighed separately, and the static moment value of all blades is recorded, and then the balance sequence is arranged in the special calculation program. Make sure that the residual unbalance meets the standard requirements, and then mark the position of each blade.

1.3.3.8.4. Hydraulic cylinder pressure test. The hydraulic cylinder is an important part imported from Denmark. Before leaving the factory, each hydraulic cylinder shall be subject to various performance tests and pressure tests according to the specification requirements to check whether the functions of the hydraulic cylinder meet the requirements and confirm that there is no leakage; in addition, it is also necessary to check whether the pressure of the hydraulic cylinder meets the requirements. Figure 6-16 shows the hydraulic cylinder pressure test.

1.3.3.9. Convenient and quick on-site maintenance. The diffuser of single-stage fan, diffuser and inlet box of double-stage fan are all supported by sliding support and are installed on the guide rail. When it is necessary to overhaul and maintain the rotating parts, pull the diffuser and inlet box along the guide rail to both sides to overhaul all the rotating parts. Fig. 6-17 shows the maintenance channel of the rotor of the double-stage fan. Because of the convenient maintenance channel, it is very convenient to repair the rotor and replace the parts. Taking the replacement of fan blades as an example, it can be completed by one person in 8 hours. The standard overhaul period is 1 week after 4 years of operation and 2 weeks after 6 years of operation. Figure 6-18 shows the blade replacement on site.

1.4. Working principle

At rated load, the efficiency of axial-flow fan under the highest design condition can reach 90%, which is close to the maximum design point efficiency of centrifugal fan. However, when the load of the unit changes, especially in the low load working state, the working efficiency of the axial flow fan with adjustable moving blade is much higher than that of the centrifugal fan. Therefore, if the unit needs to adjust the load frequently and operate under the condition of low load, the adjustable blade axial fan should be selected.

The typical arrangement of Variax variable blade axial fan is shown in Figure 6-19. The main supporting parts of the fan are divided into the fan body and auxiliary equipment, and the fan body is divided into two parts: rotating parts and static parts. The rotating parts include the main motor, coupling, main bearing group, hub, blade, hydraulic cylinder, rotary oil seal and hydraulic regulating driving device; the static parts include coupling guard, air inlet box, impeller shell, diffuser, sliding support and guide rail; Auxiliary equipment includes lubricating oil station, hydraulic oil station, servo actuator, stall probe, instrument, stall alarm system, flexible connection and sealing fan system.

The fan is driven by an electric motor. From the driving end, the rotation direction of the impeller is clockwise. The air flows into the flow passage of the fan smoothly through the inlet box. The collector and the inlet guide vane make the air flow into the moving blade of the fan evenly and produce a certain pre swirl to improve the pressure rise. When the air flow passes through the impeller, the moving blade works on the air flow and improves the pressure rise of the air flow. The best combination of the moving blade and the rear guide vane makes the air flow change direction and enter into the diffuser along the axial direction with the minimum loss The design ensures that the dynamic pressure is transformed into static pressure to the maximum extent: the angle of the moving blade of the fan can be adjusted by the hydraulic control system during the operation, so as to meet the load requirements of the unit under variable working conditions at any time.

1.5. Technical level

The development of vaniax axial flow machine with adjustable moving blade was started in 1949. In 1951, the world's first variable blade adjustable axial-flow fan was formally installed and put into operation in the power plant. Up to now, the Variax adjustable blade axial-flow fan has gone through 60 years of development. Howden has been following the development of world science and technology for many years. It pays close attention to the changes and demands of the market. While ensuring that its products have the leading technology level, Howden has been constantly improving and updating to meet the changing new demands of the market.

Up to now, varixe adjustable blade axial-flow fans have been widely used in electric power, tunnel ventilation, industrial steel furnace and mining industry, and more than 300 sets of equipment have been operating in different industrial areas of various countries in the world. In recent years, nearly 700 sets Variax adjustable blade axial-flow fan has been widely used in many thermal power plants in China, such as flue gas and air systems, desulfurization and denitrification systems. The fan has won the unanimous praise of users for its good quality, wide performance, high efficiency and energy saving, reliable adjustment, convenient maintenance and reliable operation.

1.6. Product series

Variax axial flow fans with adjustable moving blades can be classified according to their overall structure and usage. See table 6-1 and table 6-2 for specific classification.

Table 6-1

Fan series ANN series (single stage) ANT series (two stages)
Flow (m/s) 25~1600 15~1600
Inlet temperature () 20~200 20~200
Full pressure raise (Pa) 300~14000 1500~28000

 

Table 6-2

Fan application The medium is air
(such as blower,primary fan)
The medium is flue gas
(such as induced draft and and booster fan)
Hub type N type B type
Hub material Ductile iron Welded structure of high strength carbon steel
Blade Cast aluminum alloy Ductile iron
Connection between blade and hub Bolt connection Screw connection + locating pin
Main bearing lubrication Grease,oil base and oil station Oil station
Hydraulic cylinder 66,160kN 330,625,800kN
Electric actuator 50Nm 75Nm
Blade full stroke time 7~20s 15~25s
Petiole lubrication Grease Oil base
Balance arm Cast aluminum alloy Carben steel
Counterweight of the balance arm Lead Carben steel

 

2. Technical parameters

2.1. Main technical parameters

When purchasing Variax adjustable blade axial fan, the user should provide the following parameters:

2.1.1. Local atmospheric pressure or altitude.

2.1.2. Working environment temperature of fan.

2.1.3. Fan inlet pressure (absolute pressure or relative pressure).

2.1.4. Medium flow at fan inlet (actual flow or standard flow).

2.1.5. Medium density at fan inlet (actual density or standard density).

2.1.6. Medium temperature at fan inlet.

2.1.7. Total pressure rise or static pressure rise of fan.

2.1.8. Dust content of fan medium.

In addition, if the medium is corrosive or toxic, the user should also be clear, so that the fan designer can take relevant measures

Variax adjustable blade axial fan has a wide working range and can be selected according to different needs of users.

2.2. Technical parameters

If the user has special requirements for the product, the fan can be specially designed according to the specific situation to meet the different needs of users

2.3. Equipment appearance and structure

2.3.1. The appearance of ANN series fan is shown in Fig. 6-20 ~ Fig. 6-23 (taking the booster fan ANN3294 / 1800B as an example).

2.3.2.the appearance of ant series fans is shown in Fig. 6-24-fig. 6-27 (taking ANT1960 / 1400F as an example).

 

3. Selection method

Figure 6-28 relationship between operating point and performance curve

Variax The selection principle of adjustable blade axial-flow fan is that according to the parameters of each operating point provided by the user, including flow, pressure, temperature, gas density, dust content and atmospheric pressure, etc., and according to the series spectrum of all aerodynamic performance models of the fan, the optimized design can be carried out according to the size of the fan, and the fan that can meet the user's requirements can be found, and finally the same aerodynamic parameters can be ensured At the same time, it also has high operating efficiency, and there is enough safety margin between each operating point and the stall line.

After the blade profile of axial flow fan is determined, there are two main parameters that affect the aerodynamic performance range of the fan, namely impeller diameter and hub diameter. The larger the impeller diameter, the greater the fan flow; the larger the hub diameter, the higher the fan pressure. Figure 6-28 shows the variation trend of the operating point on the fan performance curve.

Therefore, after determining the speed, blade profile, hub diameter and impeller diameter, the final result of fan selection is determined.

At present, all aerodynamic performance model series spectrum of Variax adjustable blade axial flow fan has been programmed by computer, so the fan selection can be carried out conveniently and quickly in the computer according to the user's parameter requirements, and several selection schemes can be compared to optimize the design.

 

4. Selection examples

4.1. 600 MW fan selection example

See table 6-3 for fan selection parameters of typical 600MW unit.

Table 6-3 selection parameters of fans for typical 600MW Units

According to the selection parameters in table 6-3, the selection results are shown in table 6-4.

Table 6-3

Fan application Item TB working condition BMCR working condition
Primary fan Air flow at inlet (m3/s) 143 87
Full pressure raise of the fanPa 20374 14018
Air temperature at inlet(℃) 38 20
Air density at inletkg/m3) 1.13 1.12
Blower Air flow at inlet (m3/s) 298 231
Full pressure raise of the fanPa 5383 4070
Air temperature at inlet(℃) 38 20
Air density at inletkg/m3) 1.13 1.12
Induced draft fan Air flow at inlet (m3/s) 507 444
Full pressure raise of the fanPa 9448 7873
Air temperature at inlet(℃) 137 122
Air density at inletkg/m3) 0.88 0.88
Booster fan Air flow at inlet (m3/s) 942 838
Full pressure raise of the fanPa 3607 3005
Air temperature at inlet(℃) 130 120
Air density at inletkg/m3) 0.881 0.917

 

Table 6-4 selection results of fan for 600MW unit

Fan application Fan model Speedr/min) Motor powerkW)
Primary fan ANT-1960/1400F 1490 3400
Blower ANN-2800/1600N 990 2000
Induced draft fan ANT-3200/1600B 990 5900
Booster fan ANN-4360/2000B 740 4200

 

4.2.1000MW fan selection example

The fan selection parameters of typical 1000MW unit are shown in table 6-5.

According to the selection parameters in table 6-5, the selection results are shown in table 6-6.

Table 6-5

Fan application Item TB working condition BMCR working condition
Primary fan Air flow at inlet (m3/s) 151 112
Full pressure raise of the fanPa 20016 16680
Air temperature at inlet(℃) 32 20
Air density at inletkg/m3) 1.132 1.18
Blower Air flow at inlet (m3/s) 399 341
Full pressure raise of the fanPa 5935 4566
Air temperature at inlet(℃) 20 20
Air density at inletkg/m3) 1.197 1.197
Induced draft fan + booster fan
combined fan
Air flow at inlet (m3/s) 748 694
Full pressure raise of the fanPa 8679 6676
Air temperature at inlet(℃) 134 124
Air density at inletkg/m3) 0,845 0.866
Booster fan Air flow at inlet (m3/s) 744 631
Full pressure raise of the fanPa 2318 1934
Air temperature at inlet(℃) 133 123
Air density at inletkg/m3) 0.89 0.91

 

Table 6-6 selection results of fans for 1000MW units

Fan application Fan model Speedr/min) Motor powerkW)
Primary fan ANT-2100/1400F 1490 3700
Blower ANN-3120/1600N 990 3000
Induced draft fan ANT-3816/1800B 740 7800
Booster fan ANN-4240/2000B 740 2200

 

5. Scope of supply and ordering instructions

5.1. Scope of supply

The scope of supply of Variax axial fans with adjustable blades usually includes:

5.1.1. Fan body. Imported bellows, casing, intermediate shaft, diffuser, rotor, main bearing group, coupling and coupling protection cover, hydraulic control device, bellows drain pipe and valve, etc.

2.5. Motor, inlet and outlet expansion joint, lubricating oil station, hydraulic oil station, bearing temperature measuring element, electric actuator, stall (surge) alarm device, bearing vibration measuring device, foundation plate (including anchor bolt, nut and washer), muffler, primary measuring instrument for fan control, local junction box and special tools, etc.

5.2. Order requirements

5.2.1. Technical parameter requirements. When ordering, it is necessary to specify the performance parameter requirements of the fan, including the flow rate, pressure, temperature, gas density, dust content and atmospheric pressure of the fan. In particular, the purpose of the fan should be specified. If it is a special purpose, the detailed working conditions, such as wear and corrosion, should be described clearly.

5.2.2. Scope of supply. Both the supplier and the demander must define the complete supply scope of the fan, the detailed requirements of spare parts and the scope of imported parts, as well as the supplier of special parts.

5.2.3. Confirmation of delivery date. Both the supplier and the Demander shall confirm the delivery date.

5.2.4. Delivery schedule of technical data. The contents and time requirements for the submission of technical data shall be specified.