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DETAILED ENGINEERING DESCRIPTION AND MECHANICAL
FEATURES OF CONTINENTAL INDUSTRIE MULTISTAGE CENTRIFUGAL
BLOWER MODEL 400A
I - BLOWER HOUSING
The centrifugal blower housing consists of an inlet head with special feature to direct air to
inlet of first impeller and outlet head of special design to eliminate friction and multiple
intermediate sections. These parts are made in cast iron EN-GJL-250 (ASTM A48-35B)
according to rigid Continental Industrie specifications, extreme care to be exercised in
assembly of interlocking cast iron EN-GJL-250 (ASTM A48-35B) intermediate sections and
integral annular diffusers (baffles).
The heads are provided with integral mounting legs and rugged tie-rod lugs. The entire
assembly is securely held together actually with multiple tension rods which bind the entire
housing into a solid integral unit.
1.0 Inlet head
1.1 Flange connection DN 450, PN 10 (18”)
1.2 Cast iron EN-GJL-250 (ASTM A48-35B)
1.3 Minimum wall thickness: 8 mm (0.30”)
1.4 Can be supplied in various flange positions relative to the vertical centre line in
increments of 90° (option)
2.0 Outlet head
2.1 Flange connection DN 350, PN 10 (14”).
2.2 Cast iron EN-GJL-250 (ASTM A48-35B).
2.3 Minimum wall thickness: 8 mm (0.30”)
2.4 Can be supplied in various flange positions relative to the vertical centre line in
increments of 90° (option)
2.5 Has six integrally cast reinforcing ribs surrounding the volute contour and joining up
to the bearing housing mounting face for strength and to minimize vibration.
2.6 Has pipe connection to vent balancing piston leakage to inlet.
3.0 Intermediate section
3.1 Cast iron EN-GJL-250 (ASTM A48-35B).
3.2 2 Each intermediate section is cast in one piece
3.3 Each section has twelve evenly spaced integrally cast ribs for increased strength.
Increased surface area allows for proper heat dissipation.
Values, dimensions and reference in this brochure are approximate and intended as guide only, not for construction and are subject to change without notice
DETAILED ENGINEERING DESCRIPTION - CONTINENTAL INDUSTRIE
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4.0 Bearing housing
The outboard bearing housings are cast iron and bolted to the outside of the head sections
insuring cool operation of bearings.
4.1 Cast iron EN-GJL-250 (ASTM A48-35B).
4.2 Two cored openings are provided to allow circulation of air (except for gas). 4.3 Has
cast fins to improve rigidity and increase heat dissipation
4.3 Labyrinth type oil seal. Oil passages are generously sized to allow optimum
recirculation.
4.4 Has air vent and magnetic plug at the bottom of the oil reservoir.
4.5 Provided with 4 tapped holes in the housing flange to act as bearing puller.
N.B.: When the inlet air or gas temperature is too high, we can adapt as option special
bearing housings with a water or air cooling system (technical drawing on request).
5.0 Bearings
5.1 The rotor assembly is supported by 2 heavy duty oil lubricated ball bearings, single
row, sized to withstand the thrust load also type SKF or FAG.
5.2 Sized for minimum 10 years of operation (Direct Drive only), following SKF L10
bearing life calculation method.
5.3 Bearings are mounted in outboard type bearing housings and located so that
bearings may be serviced without disassembling the blower casing or piping.
6.0 Shaft
6.1 42CrMo4 (AISI 4140) carbon steel shaft, heat treated, straightened and stressreleved
6.2 Shaft is ground all over
6.3 Stiff shaft design to minimize vibration
6.4 The diameter of the shaft end is 65 mm (2.56”)
7.0 Shaft seals
7.1 Shaft sealing is accomplished using graphite ring seals or carbon ring seals.
8.0 Impellers
8.1 The impellers are fabricated in aluminium shrouds, fixed on a rigid hub in cast
aluminium.
8.2 For minimum corrosion all aluminium alloys are non copper alloys
8.3 The outer diameter of the impeller is 662 mm (26”)
8.4 Each impeller is statically balanced.
8.5 Impeller tip speed: 122 m/sec (400 FPS) at 3600 rpm.
8.6 First critical speed (7 stages) 4505 rpm.
8.7 Impeller assembly: to consist of a heavy steel shaft accurently machined and one or
more fabricated aluminium impeller(s), statically balanced, securely keyed to shaft
and held in place by lock washers and locknuts.
Values, dimensions and reference in this brochure are approximate and intended as guide only, not for construction and are subject to change without notice
DETAILED ENGINEERING DESCRIPTION - CONTINENTAL INDUSTRIE
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9.0 Casing assembly
9.1 Vertically split assembly
9.2 Heads and sections have machined male and female joints to maintain concentricity
9.3 Entire casing is retained together with ø 22 mm O.D.
9.4 Maximum allowable casing working pressure: 170 kPa (25 PSIG)
9.5 Joints are made gas tight with silicone sealant with following characteristics:
Viscosity pasty mastic glue
max. space [mm] 6
Setting time 10 mn - 24 h
Shearing's resistance [DAN/cm²] 33
Break's resistance [DAN/cm²] 8
Max. temperature of use [°C]
-60 +260
Specific weight 1,06 at 25 °C
Hardness 35 SHA
Extension 460 %
10.0 Rotor assembly
10.1 Impellers, spacer are assembled on the shaft with a push to light press fit requiring
little or no heat
10.2 Impellers, spacers are held together axially by a conventional locknut assembly
10.3 All impellers are keyed to shaft using a staggered key arrangement.
10.4 The impeller hub is fitted with a shrunk to pre-stress the bore and minimize rubbing.
This also eliminates the relative thermal expansion and contraction since hubs and
shaft are manufactured with different materials.
10.5 The rotor assembly is dynamically balanced on a computerized balancing machine
11.0 Balancing piston
11.1 Cast iron EN-GJL-250 (ASTM A48-35B)
11.2 Sized to reduce by approx. 75 % the thrust load to the outlet bearing.
12.0 Lubrication system
12.1
The bearing housings are oil lubricated (see detailed description in installation, use
& maintenance manual).
Values, dimensions and reference in this brochure are approximate and intended as guide only, not for construction and are subject to change without notice
DETAILED ENGINEERING DESCRIPTION - CONTINENTAL INDUSTRIE
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13.0 Recommended maximum allowable Piping forces and moments on blower
connections
13.1 Inlet flange
FX
= 90 KG
MX
= 135 kgm
FY
= 225 Kg
MY
= 67 kgm
FZ
= 180 Kg
MZ
= 67 kgm
13.2 Outlet flange
FX
= 70 KG
MX
= 105 kgm
FY
= 175 Kg
MY
= 52 kgm
FZ
= 140 Kg
MZ
= 52 kgm
where :
F
= force
X
= Axial - parallel to rotor centre line
Y
= Vertical
Z
= Horizontal - normal to rotor centre line.
M
= moment
14.0 Vibration and noise
Vibration tolerance: 4,5 mm/s RMS
Vibration shall not exceed 4,5 mm/s RMS when measured in the vertical plane at the
bearing housings with the blower operating at the design speed.
Sound level: please refer to the calculation data sheet
II - PERFORMANCES
1.
All tests if required are in conformity with ASME Power Test Code.
2.
For constant speed blowers:
-
The head shall be within the range of 100% - 105% of the normal head at design capacity,
-
The horsepower based on measured head shall not exceed 107% of the value at the specified
normal operating point.
3.
For variable speed machines:
-
through the rotational speed, the head shall be adjusted as close as possible to the design point,
with zero negative tolerance,
-
the horsepower at that point shall not exceed 104% of the predicted shaft power value.
Values, dimensions and reference in this brochure are approximate and intended as guide only, not for construction and are subject to change without notice
DETAILED ENGINEERING DESCRIPTION - CONTINENTAL INDUSTRIE
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