ADVANCED TECHNOLOGY FOR AXIAL-FLOW FANS WITH VARIABLE PITCH CONTROL Presented by:
Aerodynamic Performance Figure is a typical performance field of a variable pitch axial flow fan, showing the shape of the efficiency curves relative to a system resistance line. Areas of constant efficiency have their longest dimension parallel to the resistance line providing efficient performance across a range of load points. The resulting benefit is to minimize the net system operating power requirements. Maximum design conditions and/or test block conditions remain within the control range of the performance field.
General Fan Arrangement 1-Stage Fan-Horizontal Installation
General Fan Arrangement 2-Stage Fan-Horizontal Installation
General Fan Arrangement Vertical Installation Vertically mounted flue gas fan to fit special plant design. This feature is especially important when plants are retrofitted with pollution control equipment and space is at a premium.
Rotor Assembly Blades Replaceable in built-in state Blade shaft assembly All bearings are oil-lubricated for long term overhaul periods Rotor hub Rotor cover parts Thrust mechanism Welding assembly with spherical outer shell and forged parts For protection of interior rotor parts against corrosion As linkage for conversion of axial into angular motion Main bearing assembly Hydraulic adjustment unit Compact design available as antifriction - or sleeve bearing Capability for high pressure without leakage
Rotor with coupling half fixed on transportation frame Rotor Assembly 1-Stage Design Interior parts with hydraulic adjustment unit
Rotor Assembly 2-Stage Design Major Components 1 set of blades for each stage 2 impeller assemblies with blade shaft assembly and hubs 1 Hydraulic adjustment unit 1 compact main bearing 1 trust device with thrust disks for each stage
Blade Base Materials Forced draft fan Primary air fan Induced draft fan Flue gas booster fan (Pos. A) Flue gas booster fan (Pos. C) Cast aluminium alloy Forged aluminium alloy Nodular cast iron Forged steel Forged steel with carbide alloy coating Nickel alloy Flue gas booster fan (Pos. D) Austenit-ferritic stainless steel Steel cast material
Application for Blade Materials Forged steel blades for induced draft fans (Pos.A) Aluminum alloy for forced draft & primair air fans
Blade Disadvantages of Alu Blades for Flue Gas Fans High losses of tensile strength at impact of high temperature Corrosion at operating conditions below dew point at start-up and operating conditions High abrasion even at medium dust loads > 50 mg/nm³ Abrasion even at normal dust load conditions < 50mg/Nm³ General: Aluminium bades to be used for forced draft fans and primary air fans only
Blade Bearing Assembly Characteristic One basic design Optimized bearing arrangement Oil Lubrication of all bearings Dual chamber design, oil circulation during start up Adequate sealing system Oil change Advantage Suitable for all fan duties with blade materials of different densities Reduced weight of impeller assembly Low friction losses at low adjusting forces Allows 5-years operation without outage Prevents oil leakage during operation Without assembly of blade bearings
Impeller Hub Assembly Hub Dia. 2500 mm with 20 Blades
Blade Bearing Assembly Special Components Individual design of deep groove ball bearing with regard to special operating conditions Modified bearing to increase static fatique rate value Optimized ball size with regard to max. load angle
Blade Bearing Assembly 3D Model Flue Gas Booster Fan Tip dia. 5014 mm Hub dia. 2510 mm 20 blades per stage Operating speed 590 rpm Tip speed 154,9 m/s Forged steel blades
Blade Bearing Assembly Test Results of Lubricants Adjusting Moment [Nm] 350 300 250 200 150 100 50 0 0,2 0,4 0,6 0,8 1 1,5 2 2,5 3 4 5 6 Load Cycle [Million hrs.] Molycote Petamo Berutox Barierta Mobile Grease Mobile Glycol
Blade Bearing Assembly Advantages of Oil Lubrication Continously lowest adjusting forces during operation period. Consistent against high temperature and centrifugal forces. Two-chamber oil floating system for lubrication of all blade bearings Additional lubrication of slide blocks and adjusting levers during start-up Easy change of lube oil without bearing disassemly Low capital cost in comparison special grease.
Impeller Hub Forged load ring to carry centifugal forces Inner guide ring to fix oil lubricated counter bearings and counteract to lateral forces caused during blade pitch adjustment Forged welding hub with conical shrink fit to main shaft Spherical contour of outer shell to maintain low gap to to blade during all operating conditions Labyrinth seals for Induced draught fans ( Pos. A ) and especially for wet fans ( Pos. C )
Impeller Hub after Machining
Impeller Assembly Hub Dia. 2500 mm with 20 Blades
Compact Main Bearing Preface Special design for radial and thrust loading of variable pitch axial flow fans Impellers are mounted close to the bearings to minimize overhung and gyroscopic effects during rotation. Flange connection to fan housing enables a short exchange of the spare rotor. Antifriction and sleeve type are available for horizontal and vertical installation. Lubrication for antifriction bearings is achieved by oil splash bath or forced lubrication Lubrication for sleeve bearings is achieved by forced lubrication only.
Main Antifriction Bearing 1-Stage Design 2-Stage Design Combination of angular contact bearings to pick up radial load and thrust at drive end side Roller bearing to pick up radial load at fan side Unsplitted bearing housing with high capacity oil sump Forced feed lubrication or oil sump splash lubrication Combination of angular contact bearings to pick up thrust load only at drive end side Roller Bearing to pick up radial load of 1. stage impeller at drive end side Roller Bearing to pick up radial load of 2. stage impeller at fan side. Unsplitted bearing housing with high capacity oil sump Forced feed lubrication or oil sump splash lubrication
Main Antifriction Bearing 2-Stage Design
Main Antifriction Bearing Workshop Assembly
Main Antifriction Bearing Mechanical Running Test
Main Sleeve Bearing Design Features Arrangement of self adjusting thrust pads around collar ring to pick up thrust loads at drive end side Cylindrical sleeve bearing to pick up radial load at drive end side Cylindrical sleeve bearing to pick up radial loads at fan side. Compact housing is horizontallv split to enable exchange of individual bearings without dismount of impeller. Internal friction pump, energized by the rotating main shaft extends the operation period at emergency
Main Sleeve Bearing Sectional Drawing Internal radial bearings with spherical outer diameter for alinement of bearing to shaft position One friction pump for all bearings
Compact Main Bearing Standard Program, Horizontal Installation Antifriction Type 1-Stage Design Antifriction Type 2-Stage Design Sleeve Bearing Type HHW1-110 HHW2-110 HHG-110 HHW1-130 HHW2-130 HHG-130 HHW1-150 HHW2-150 HHG-150 HHW1-180 HHW2-180 HHG-180 HHW1-200 HHW2-200 HHG-200 HHW1-240 HHW2-240 HHG-240 HHW1-280 HHW2-280 HHG-280 HHW1-320 HHW2-320 HHG-320
Blade Adjustment Mechanism Comparison of Variuos Systems Pneumatic for industrial application of low capacity fans Electro-Mechanical for mine fans Mechanical, for simultaneous adjustable blades at stand still Oil hydraulic for heavy duty fans at power plants, mines and tunnel ventilation
Blade Adjustment Mechanism Hydraulic System 1 Contol head of hydraulic (stationary) 2 Hydraulic cylinder (rotating & axial motion) 3 Adjusting lever (rotating & angular motion) 4 Thrust device (rotating & axial motion) 5 Counter bearing (rotating & angular motion) 6 Blade shaft (rotating & angular motion) 7 Thrust bearing (rotating & angular motion) 8 Blade (rotating & angular motion)
Blade Adjustment Mechanism Function an Design Adjusting cylinder is rotating with rotor and axially moving along the fan axis Piston is rotating with cylinder, but is axially fixed to the rotor Feed back rod is telescopally arranged to piston rod Control head in stationary arrangement receives the signal from the setting drive,fixed to the housing.
Blade Adjustment Mechanism Description Adjustment unit consisting of 2 major sections : High pressure actuator unit Control unit governed by low energy signals Double acting cylinder with oil ports on both sides allows motion axially in both directions. Servo valve is directing the high pressure oil to the appropriate area in the cylinder actuated by the axial movement of the control gear. Axial movement and direction of control gear are governed by the actuator located at outer shell of fan housing. Actuator is controlled by low energy signal (4 20 ma) from the boiler or FGD-plant.
Blade Adjustment Mechanism Characteristic of Hydraulic Cylinder Unit High operating pressure No slip stick Low adjustment force Direct conversion of angular movement into axial movement Low setting times Allows fan design without counter weight High setting accuracity Low hysteresis Low energy signals from 4 to 20 ma. High conformability to electronic control signals
Hydraulic Adjustment Unit Size: HYS-220 x 80
Hydraulic Adjustment Unit Standard Program, Type HYS Hydraulic Size Piston Dia [mm] Max. Stroke [mm] Total Weight [kg] Moment of Inertia [kgm²] Max. Thrust [KN] Max. Speed [rpm] Oil Delivery [l/min] 120 x 40 120 40 30 0.108 113.1 3000 0.91 170 x 62 170 62 50 0.320 254.3 1500 5.08 220 x 80 220 80 110 1.331 452.4 1500 6.08 300 x 100 300 100 210 4.725 706.9 1000 14.14 360 x 125 360 125 360 6.804 1017.9 1000 20.36 420 x 160 420 160 570 25.137 1590.4 750 47.13
Hydraulic Adjustment Unit Max.Thrust Load Thrust [KN] 1600 1400 1200 1000 800 600 400 200 0 150 180 220 300 360 420 Cylinder Dia. [mm] Annular Section Ring Section
Hydraulic Adjustment Unit Assembly One complete unit standardized for axial fans with inflight variable pitch control One double acting cylinder for blade adjustment One control head to convert input signal into axial movement of the cylinder Automatic feed back provided by the control head
Impeller Assembly Stationary Test of Blade Adjustment
Hydraulic Adjustment Unit Testing Equipment Performance test at original operating speed Back to back arrangement for testting of two units in one procedure Computerized testing program with test certificate Monitoring of testing pressure, temperature and leakage flow
Hydraulic Adjustment Unit Advantages High operating pressure No slip stick Low adjustment force Direct conversion of angular movement into axial movement Low setting times allows also fan design without counter weights High setting accuracity Low hysteresis Low energy signals from 4 to 20 ma. High conformability to electronic control signals
Stationary Steel Parts Components Suction box Welding assembly Material S235JR Fan housing Welding assembly with machining Material S235JR Diffuser housing Welding assembly Material S235JR Turning bend Welding assembly Material S235JR With bellmouth, fairing nose, intermediate shaft cover Hub thermal insulated for IDF Top part and lower housing inclusive guide vanes and straightener vanes With fairing tail With turning vanes, single thickness or air foil profile
Stationary Steel Parts Suction Box
Stationary Steel Parts Steel Fabrication of Fan Housing
Stationary Steel Parts Diffuser
Stationary Steel Parts Site Erection
Drive Unit Main Motor Three phase AC induction motor High voltage power Single speed application only Air cooled or water cooled Insulation class F in compliance with IEC 85
Drive Unit Flexible All Steel Coupling Backlash-free power transmission due to discs of stainless spring steel Both coupling halves are flange connected by spacer through protected channel in suction box Compensation of angular, radial and axial misalinement of the connected shaft ends within specified tolerances
Drive Unit Intermediate Shaft with Flexible Coupling Long intermediate shafts apply for standard applications with outline motor. The connection between rotor and drive motor is accomplished by an intermediate shaft with two torsional rigid shackle spring coupling halves. Picture below shows the arrangement for 1-stage fan. Intermediate shafts flange connections at both ends to the disc packs. Addionally brake disc can be assembled to the coupling half at motor side, if brake system is requested.
Drive Unit Coupling Half with Disc Brake Installation of fixing brake at motor side Brake is closed, when fan is stationary Brake disc is connected to coupling half Brake position is controlled by sensor
Auxiliary Equipment External Oil Supply Unit
Auxiliary Equipment Cooling and Seal Air System
Auxiliary Equipment External Centrifugal Fans for Air Supply
Instrumentation- & Control System Local Panel Instrumentation Temperature indication Pressure control Stall control Volume flow Vibration monitoring Speed control
Instrumentation- & Control System Stall Pevention System Functions Calculation of actual operating data Comparison of actual operating point with admissible limit value Alarm to the operator in case of exceeding the limit curve Reduction of blade pitch back to stable operation
Instrumentation- & Control System Instrumentation for Pressure Control
Instrumentation- & Control System Local Display of Vibrations
Miscellaneous Equipment Fan Foundation Dynanic and structural analysis for spring supported fan foundation Engineering of spring foundation drawing Reinforcement drawing for spring foundation Delivery of fan anchoring parts Delivery of anti-vibration dampers
Miscellaneous Equipment Sound Attenuation Basic engineering for insulation and lagging Rectangular absorption silencers for inlet and outlet sound attenuation of forced draft fans and primary air fans Resonant silencers for inlet and outlet sound attenuation of induced draft fans and FGDbooster fans Silencing hoods for auxiary sealing air fans and oil supply units
Synopsis Advantages of our Technology High aerodynamic performance at full part load conditions of boiler and FGD Quick rotor exchange without any alignment of drive motor Forged Steel blades with coating allow high wear resistance at high dust loads Dual chamber ring lubrication for all blade bearing Compact main bearing program of antifriction and sleeve type Double acting high pressure hydraulic with internal feed back to enable adjustment < 10 s Horizontal splitted fan housing Low power consumption and savings of operating costs Increase of availability during guarantee period Extended life rate for blades against erosion Easy and quick exchange of oil without acces to inerior Impeller parts Interchangeability of sleeve bearing type to antifriction bearing or in reverse Protection for boiler against implosion at fuel trip Enables quick accessto the rotor.