Howden Axial Fan
Presentation
Howden Hua Engineering Co., Ltd
Sep. 2004
The Howden Port Folio
Axial Fans
Air Preheaters
Gas/gas Heaters
Cooling Fans
Centrifugal Fans
Dampers
Blowers
For the power industry
For the mining and pelletizing industry
For tunnels and metros
For cleanrooms and other industrial purposes
Our facilities
Næstved, Denmark
Engineering, production, project management
and proposals for Axial fans
Site area
Manufacturing area
Quality assurance
Employees
Transport
Design tools
6.9 hectare
9300m2
ISO 9001
212
Road, sea
Finite elements
Computational fluid dynamics
Dynamic response analysis
AMCA model test stand
Manufacturing capacity of 130,000 man hours per year based on current manning levels.
Additional facilities
Weihai, China
Manufacture of static parts to Axial fans
Site area
Manufacturing area
Quality assurance
Employees
Transport
Test facilities
3 hectare
10,000m2
ISO 9001
220
Road, Rail, Sea
1350kW aerodynamic test
Manufacturing capacity of 330,000 man hours per year based on current manning levels.
The Variax® Fan for Power Plants
Applications
•
•
•
•
•
•
•
Forced Draught Fans
Primary Air Fans
Induced Draught Fans
A-Position Booster Fans
C-Position Booster Fans
D-Position Booster Fans
Combined ID and Booster
Fans
• Gas Recirculation Fans
• Secondary Air Fans
VARIAX
Axial flow fan
To Stack
D-Position
Boiler
Coal
Tower
SCR
GGH
D-Position
ECO
Bu
C-Position
APH
EP
FD
GGH
FGD
Air
NH3
Air
ID
or
A-Position
CaCO3
H20
Waste
Water
PA
Gypsum
Schematic drawing of a typical German Power Plant
The Variax® Fan
Variable Pitch Axial Flow Fan
Vari
Ax
Variax
Fan Performance Curve
Nominal Pressure Constant
Fan
Work
1
2
1
3D
D
Howden Var i ax
2
Lower Hub diameter
88% 87%
86%
82%
80%
85%
84%
75%
70%
Higher
65%
60%
Lower Blade diameter
55%
Higher
35%
30%
40%
50%
45%
Nominal Volume Constant
Volume
Fan Designation
AN N - 4000 / 2000 B ; 710
Rotational Speed in rpm
Hub Type
Hub diameter in mm
Impeller Diameter in mm
N = Single-stage ; T = Two-stage
AN = Axial, Enlarged Inlet Box
AS = Axial, Standard Inlet Box
Types of The Variax® Fan
Variax® Type ANN
Single-stage fan
Pressure from 300 to 12000 Pa
Volume flow from 25 to 1100 m3/s
Variax® Type ANT
Two-stage fan
Pressure from 1500 to 25000 Pa
Volume flow from 15 to 1175 m3/s
Single-stage Axial Flow Fan
Diffuser
Impeller
casing
Control drive
Inlet box
Blades
Hub
Coupling
Main motor
Coupling guard
Two-stage Axial Flow Fan
Inlet box
Intermediate piece
Impeller
casing
Diffuser
Blade
Main motor
Couplings
Man hole Control drive
Hub
Main bearing
assembly
Shaft
Coupling guard
Rotating parts
•
•
•
•
•
•
Hub
Blades
Blade Bearings
Hydraulic Regulating Unit
Main Bearing Assembly
Coupling
Hub Types
B-Hub
SG-Iron
Fabricated/Machined Hub
Howden Variax always
selects the best hub type
for a specific application
ensuring the lowest
overall costs
N-Hub
SG-Iron
Cast Hub
N-Hub
All normal maintenance
can be done on site
meaning short
Balancing block
outage time and
minimum strategic
spare parts.
Blade
Blade pivot
Blade bearing
Regulating disc
Hub cover
Balancing arm
Regulating arm
Hydraulic cylinder
Support cover
Rotating oil seal
Slide shoe
Guide pin
Hub
Main shaft
B-Hub
All normal maintenance Sealing ring
can be done on site
meaning short
Balancing block
outage time and
minimum strategic
spare parts.
Blade
Blade pivot
Blade bearing
Regulating disc
Regulating arm
Hydraulic cylinder
Slide shoe
Hub boss
Rotating oil seal
Main shaft
B-Hub
The B-Hub is designed to
carry both aluminium and
nodular cast iron
blades.
The blade balancing
arm results in 100%
balancing of the
blade centrifugal
moment resulting
in the same regulating
force in both directions.
Blades
Profiles
• Medium Pressure Profile
• High Pressure Profile
• Volume Profile
Erosion Shields
Stainless steel with
hard chromium layer
Materials
• Cast Aluminium
• Forged Aluminium
• Nodular Cast Iron
• Cast Steel
• Cast Nickel Alloy
Each individual blade is balanced and the blades can
be replaced on site without rebalancing of the
complete rotor
Blade profiles
Howden offers 4 different
kinds of blade profiles:
The high-pressure profile
with pre-swirl inlet guide
vanes
The high-pressure
profile
The volume profile
The medium-pressure
profile.
Prepared for FGD or SCR
The use of VARIAX flexible
guide vanes and medium
pressure profile secures
easy replacement to high
pressure profile when
implementing FGD or SCR
The medium-pressure
profile with duty points
BEFORE FGD or SCR.
The high-pressure
profile with duty points
AFTER FGD or SCR.
TB
TB
MCR
MCR
Erosion Shields
Allowance for Erosion Shield is built into blade castings
designed for erosive service.
Blade Bearings
Blade bearings with oversized balls are oil bath lubricated. Static and
dynamic seals prevent oil leakage from the blade bearing cavity
Blade Pivot
Only one Pawl in the air stream
results in a measurable efficiency
increase.
Attachment of blade to blade pivot is via
threaded connection with key
Exchange of blades
The blades on
a VARIAX fan
can easily be
changed
through the
man hole
Down Stream Guide Vanes
Blades and down stream guide vanes
Blades
air direction
direction
of rotation
Guide vanes
Model test
* 1000
14
84%
12
86%
82%
85%
Fan work Yt [J/kg]
During extensive
research and
development in
our aerodynamic
laboratory a high
pressure profile
has been developed
giving up to 40%
more volume flow
and 30% more
pressure
87%
10
8
88%
89% 85%
84%
87%
82%
86%
88%
80%
80%
75%
70%
65%
60%
75%
6
4
2
55%
70%
50%
65%
60%
55%
50%
45%
40%
45%
40%
35%
55°
30%
75°
35% 50°
45°
70°
40°
55°60° 65°
30%
50°
35°
45°
35°40°
20° 25°30°
30°
15°
0
0
200
400
600
800
Volume flow rate qv1 [m3/s]
85°
80°
1000
1200
Model test
Model test can be
carried out in our
own laboratory. The
model test i carried
out in accordance
with AMCA802 which
requires a minimum
outer diameter of 900
mm in order to obtain
performance equal to
the full size fan.
Model test
Full scale laboratory
test at IHI in Japan.
The fan is a VARIAX
type ANN-5300/2500B
Blade Models
Howden Variax
has supplied
the following
blade materials:
Cast Aluminium
Forged Aluminium
Nodular Cast Iron
Cast Steel
Forged Steel
Cast Stainless
Steel
Forged Stainless
Steel & Nickel Alloy
Weight 42 lbs
Height 35.3 In
Material
Alu
137 lbs
36.9 In
Nickel
57 lbs
52.1 In
Alu
? lbs
177 lbs
63.0 In
33.1 In
90% H2O
Iron
66 lbs
25.1 In
Nickel
Balancing
•All blades are balanced
separately
•All blades are numbered
•Blade position on the hub is
calculated
•No re-balancing of rotor on site
Bearing Housing
Custom designed bearing housings provide
large reservoirs for lubricants.
Roller bearing
The roller bearing assembly is either oil sump lubricated or forced oil
lubricated. The radial bearings are designed for L10 = 100.000 hours
and the axial thrust bearing is designed for L10 = 70.000 hours
Sleeve bearing
The sleeve bearing
assembly consists of
two split pillow block
bearings.
One housing with a
radial and an axial
thrust bearing.
And one with a radial
bearing.
Both bearing
housings are forced
lubricated.
Load test
All main bearings are passing a
full speed/full load test before
leaving the factory to ensure
that no unforeseen temperature
rise on the bearing will occur after
the fan is in operation.
The result is stable working
conditions and prolonged life time.
Hydraulic cylinder
The hydraulic cylinder is
designed for accurate
control of fan blades
during operation and it
operates with
continuous oil flow
ensuring immediate
response and creating
stable boiler operation
Regulating Test
The regulating test
is done on every hub
leaving the factory to
minimise the regulating
forces and thus the
load on the regulating
parts ensuring minimum
wear and low
maintenance costs
Static Parts
Inlet Box
Impeller Casing
Diffuser
Sealing Air
Intermediate Piece
Oil Supply Units
Inlet box
The guide vanes of the
inlet cone mounted in
the inlet box supplies
the air or flue gas to the
fan blades at the optimum
angle creating high
efficiencies.
Diffuser
The one-of-a kind
rolling diffuser
ensures easy
access to all wear
parts and a high
maintainability
of the fan
Roller skates
The unique roller
skate is mounted
under the diffuser
and inlet box
(on two stage fans).
The roller-skate
ensures easy
maintenance and
high flexibility.
Vibrations
Howden Variax
can rebalance the
hub after installation
on site ensuring
that the vibration
level is always low.
This means that
the fan life time
is prolonged.
Criteria for design
•
•
•
•
•
•
•
Aerodynamic airways
High efficiency
Low sound level
Low cost operation
Easy maintenance on site
High design flexibility
High level of technology
The high working reliability of the Variax fan is a result of intensive development
work with focus on the needs of the end customer over a long period of time; and with
regard to design and service the fan meets the customers’ high demands for quality and
is in accordance with all the recognised quality standards.
The Standard Variax Concept
• Low initial costs
• Low maintenance costs
• High maintainability
• High durability
• High reliability
• Customised solutions
based on standard components
A study of 28 large induced draught fans in the US
showed an average reliability of 99,8% based on more than
one million operating hours.
Total Quality
• Design meets all standards
• Fans cover all applications
• Manufacture, project management,
support and service world wide
• Model and full scale tests, full-load
running test and balancing
• Approved according to ISO 9001
• Each fan is supplied with a detailed
quality plan
• Howden Power was the first fansupplier to be ISO 9001 certified
Work shop tests
• Full load & full scale test of
bearing assembly
• Regulating test
• Test of regulating area
• Balancing of hub
• Balancing of each blade
individually
• Pressure test of hydraulic
cylinder
Efficiency for VP Axial
* 1000
1. 4
82%
80%
1. 2
F a n w o r k Y t [ f t g a s c o l u mn ]
As the optimal
efficiency for a
VP Axial is at a
reduced blade
angle the Boiler
MCR duty will
have the
highest
efficiency and
thus the lowest
power
consumption
1. 0
88% 87%
86%
85%
84%
75%
70%
65%
60%
0. 8
85
0. 6
55%
50% 75
0. 4
4 5 %7 0
4 0 %6 5
35%
3 0 %6 0
0. 2
0. 0
0. 0
80
3 0 3 5 4 04 5
1. 0
2. 0
50
3. 0
55
4. 0
5. 0
6. 0
V o l u me f l o w r a t e q v 1 [ a c f m]
7. 0
8. 0
9. 0
* 100000
Outstanding references
Naantali Power Station Finland
250 MW, Coal Fired Horizontal
D-Position Booster Fan
Variax Type ANC-3600/1800
383 m3/s, 740 rpm, 1712 kW
Delivered 1991
Herne Power Station
Germany, 500 MW - Coal Fired
Vertical C-Position Booster Fan
Variax Type ASF-4375/2500
597 m3/s, 595 rpm, 4000 kW
Delivered 1987
Asnæs Power Station
Denmark, 695 MW - Coal Fired
Horizontal C-Position Booster Fan
Variax Type ANE-4500/2240
800 m3/s, 590 rpm, 3870 kW
Delivered 1991
Tsuruga Power Station
Japan 700 MW
Coal Fired
Horizontal
D-Position
Variax Type
ANN-5300/2500
945 m3/s
510 rpm
3478 kW
5300
1900
Questions