Novenco Centrifugal Fans CNA and CNB by cmlang

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									Novenco Centrifugal
 Fans CNA and CNB
Product description
Product                                   Impeller, CNB + CNB-M:
Single inlet low pressure fans with       Welded Cor-ten steel sheet, hot-dip
backward curved blades.                   galvanized.
                                          Inlet cone CNA/B:
Application                               CNA/B -250 to -630: Hot-dip gal-
In industrial ventilating systems for     vanized deep drawn sheet, un-
clean and non-corrosive air, max.         painted.
70º C, and with requirements for a        CNA/B -710 to -1000: Cast alumi-
low sound level. For type M for           nium, unpainted.
mushroom plants in greenhouses
and working up.                           Corrosion classification
                                          Fulfils the following international
Range                                     standards for operation in unheated,
CNA: 9 sizes with impeller dia-           low-corrosive environments:
meters from 250 to 1000 mm. Air           DK:DS/R 454, klasse 2.
quantities from 0.2 to 14 m3/s and        S: BK N-4, klass M2.
pressures up to 1000 Pa.                  GB:BS 5493:1977
                                          D: DIN 55928, Teil 1.
CNB: 7 sizes with impeller dia-
meters from 400 to 1000 mm. Air           Technical classification
quantities from 0.8 to 18 m3/s and        The capacities comply with the re-
pressures up to 1500 Pa.                  quirements according to BS 848, Part
                                          1, arrangement D.
Construction
Fan casing with rectangular side          Accessories
plates for universal mounting.            Installation:
The fan is available in direct connect-   – Flexible connections
ed or belt driven design.                 – Counter flanges
                                          – Anti-vibration mountings
Materials and surface                     – Common base frame (fan and mo-
treatment                                   tor)
Casing, CNA/B:                            Control:
Sendzimir-galvanized (hot-dip gal-        – Inlet vane control
vanized) steel sheet, unpainted.          – Stepless controller (CNA-250 and
Casing, CNA/B-M:                            315 single-phase direct coupled
Sendzimir-galvanized (hot-dip gal-          motor)
vanized) steel sheet with epoxy coat-     – Three-stage controller (CNA-250
ing.                                        and 315 single-phase direct coup-
Impeller, CNA -250 to -630:                 led motor
Spot welded, galvanized steel sheet.      – Three-phase multi-speed motor
Impeller, CNA -710 to -1000:                for 2 speeds
Welded Cor-ten steel sheet, hot-dip       – Frequency converter, three-phase
galvanized.                                 motors
Impeller, CNA-M -250 to -630:             Protection:
Spot welded, galvanized steel sheet       – Wire guard (inlet and outlet)
with epoxy coating.                       – Inlet cone of brass
Impeller, CNA-M -710 to -1000:            Service:
Welded Cor-ten steel sheet, hot-dip       – Inspection and cleaning doors
galvanized.                               – Drain connection


        136 CNA                              Owing to continued product development Novenco reserves the right to introduce alterations without prior notice
Novenco Centrifugal Fans
CNA and CNB

Description                                 138

Dimension sketches                          139

Mounting of motor – Position designations   140

Accessories                                 141

Performance curves                          142

Sound conditions                            147

Control of air quantity                     148
Low pressure centrifugal fans types CNA and CNB
Centrifugal fans types CNA and            greased for life (please see mainten-
CNB are light-weight, compact low         ance instructions).
pressure fans designed for universal
installation in light industrial sys-     Surface treatment
tems.                                     All fan parts are protected against
                                          ordinary atmospheric corrosion.
Type CNA is available in nine sizes
with impeller diameters from 250          Accessories
mm to 1000 mm, air quantities from        Motor according to specification.
0.2 m3/s to 14 m3/s and total pres-
sure up to approx. 1000 Pa.               Motor mounting plate for mounting
                                          of motors not exceeding the sizes
Type CNB is available in seven sizes      stated on page 140 for the flanges of
with impeller diameters from 400          the fan casing. The mounting plate is
mm to 1000 mm and is designed for         adjustable for tensioning of the belts.
higher speeds with air quantities
from 0.8 m3/s up to 18 m3/s and a to-     Base frame for mounting of motors
tal pressure up to 1500 Pa.               larger than the sizes stated on page                       Inspection door in fan casing scroll
                                          140 beside the fan.                                        plate.
Both CNA and CNB comprise the             The sizes –250, –315 and –400 are
following main components:                also available with direct coupled                         Drain connection, please see page
                                          flanged motor mounted on the rear                          141.
Fan casing made up of two rectan-         side plate of the fan.
gular side plates and a scroll plate.     The sizes –500 and –630 are also                           Positions
                                          available with direct coupled foot-                        Direction of rotation RD or LG.
Inlet cone fitted in the front side       mounted motor mounted on ped-                              Motor positions 1, 2, 3 and 4 refer to
plate of the fan with spigot for duct     estal.                                                     the location of the motor in relation
connection. The inlet cone is special-                                                               to the outlet opening.
ly designed to guide the air to the im-   Belt drive consisting of pulleys, v-
peller without loss in pressure.          belts, and belt guard.

Material:                                 Flexible connections for inlet spigot
CNA/B -250 to -630: Electrically gal-     and outlet flange.
vanized deep drawn sheet.
CNA/B -710 to -1000: Cast alumi-          Counter flange for fan outlet flange.
nium.
                                          Wire guard for inlet opening.
Impeller with broad, backward
curved blades.                            Anti-vibration mountings.

Bearing assembly with two dust            Inlet vane control for control of fan
and waterproof, totally enclosed          capacity.
deep groove ball bearings in a flange     An inlet flange is required for the
bearing casing, mounted on the rear       mounting of the inlet vane control on
side plate of the fan or two flange       sizes -710 to -1000.
bearings mounted in two covers.           Inlet flange for mounting on fan in-
Bearing assembly on CNB-500 to -          let spigot. Also used for attachment
1000 must be greased, the others are      of flexible connection to the inlet
                                          vane control.


        138 CNA                              Owing to continued product development Novenco reserves the right to introduce alterations without prior notice
Centrifugal fans CNA and CNB
Dimension sketches




Direct coupled:                                                                             With belt drive:
CNA-250, -315, -400                          CNA-500, -600                                  All sizes
CNB-400                                      CNB-500, -630


                                                               Dimensions in mm                                                                       Weight*, kg
    CNA
               A         B        C          D           E     F        F1        G        G1         H           H1    J        L      M        N     CNA      CNB
    CNB
    –250     250       175        30       250        235    310       250       245       200       560      445      150      207    60       12       22       –
    –315     315       220        30       315        280     410      280       345       250       690      595      160      252   100       12      35        –
    –400     400       280        30       400        340    485       315       400       300       800      700      145      312   100       12       53      55
    –500     500       350        35       500        420    600       400       500       350      1000      850      170      392   125       15      89       98
    –630     630       440        35       630        510    758       488       623       440      1246     1063      250      482   125       15      146     161
    –710     710       497        40       710        577     870      535       670       465      1405     1135      260      537   62,5      15      238     262
    –800     800       560        40       800        640    976       604       754       516      1580     1270      280      600    85       15      304     334
    –900     900       630        45       900        720    1098      680       847       573      1778     1420      300      680   110       15      350     385
   –1000     1000      700        45       1000       790    1215      750       940       640      1965     1580      360      750    90       15      487     535
                                                                                                                                 *Weight excl. of motor and belt drive


Outlet flanges

     CNA
                 P           R         S          T
     CNB
      -250      207         85         282        110
      -315      252        110        347        142,5
      -400      312        140         432        185
      -500      386        125         536        155
      -630      476        170         666        200
    -710        537        150         750        170
    -800        600        170         840        175                             Sizes –250, –315, –400                    Sizes –500, –630
    -900        680        195         950        200
   -1000        750        160        1050        180

Counter flanges (4 strips) with bolt
holes as in the outlet flanges are availa-
ble as optional extras.
Ducts are made with the same inside
dimensions as the fan outlet opening
(A x B).



                                                                                    Sizes –710, –800, –900                    Size –1000



Owing to continued product development Novenco reserves the right to introduce alterations without prior notice                             CNA       139
Centrifugal fans CNA and CNB
Motor mounting arrange-
ments
The tables show the maximum mo-
tor sizes that can be mounted direct
on the fans.


                                                   Motor on side                                                Motor on top
Motor sizes for direct
                                                   – vertical mounting plate                                    – horizontal mounting plate
coupled

     Fan size         Motor size                                    Max. motor                                                 Max. motor
                                        CNA CNB                                                      CNA CNB
 CNA-250                 71-90                                 Type           Weight                                        Type         Weight
 CNA-315                71-100                    –250           90              20                     –250                 90              20
 CNA/B-400              80-100                    –315          112              40                     –315                112               40
                                                  –400          112              40                     –400                112              40
 CNA/B-500              112-132
                                                  –500          132              70                     –500                132               70
 CNA-630                  132
                                                  –630          132              70                     –630                132              70
 CNB-630                  160                     –710          132              70                     –710                160              140
                                                  –800          132              70                     –800                160              140
                                                  –900          132              70                     –900                180*             190
                                                 –1000          132              70                    –1000                180              190
                                                                                                                                *CNA max. 160
Base frame for fan and
motor
Motors of larger sizes should be
mounted on slide rails beside the
fan.
A common base frame supporting
both fan and motor as illustrated in
the sketches can be supplied. Please
specify required motor position
(pos. W or Z, please see below).

Position designations
according to EUROVENT

Note:
Fan positions for base frame
mounting must be in accordance
with EUROVENT.

Shaft extension                        CNA          d           I         b           t              CNB              d          I       b         t
                                       –250      24 j6        50          8        27
                                       –315      24 j6        50          8        27
                                       –400      24 j6        50          8        27                –400           28 j6       50       8         1
                                       –500      28 j6        50          8        31                –500          38 k6        90      10         41
                                       –630      32k6         60         10        35                –630          48 k6        90      14         51
                                       –710      35h8         100        10        38                –710          55m6        100      16         59
                                       –800      40h8         100        12        43                –800          55m6        100      16         59
                                       –900      40h8         100        12        43                –900          60m6        115      18         64
                                       –1000     55h8         100        16        59               –1000          60m6        115      18         64




        140 CNA                         Owing to continued product development Novenco reserves the right to introduce alterations without prior notice
Centrifugal fans CNA and CNB
                                                                                                                             Accessories
                                                                                                                             Types CNA and CNB are available
                                                                                                                             with inspection door in scroll plate of
                                                                                                                             casing and drain connection.
                                                                                                                             When ordering please state location
                                                                                                                             of inspection door and drain connec-
                                                                                                                             tion in relation to the outlet direction,
                                                                                                                             e.g.
                                                                                                                                Inspection door
                                                                                                                                pos. RD 120.
                                                                                                                                Drain connection pos. RD 180.
Flexible connection, outlet                                  Drain connectionInspection door

                                                                                                                              CNA
                                                                                                                                        A            B         D         E    F
                                                                                                                              CNB
                                                                                                                              –250         310       280      250         4   10
                                                                                                                              –315         385       355      315         8   10
                                                                                                                              –400         480       450      400        8    12

                                                                                                                              –500         590       560      500        12   12

                                                                                                                              –630         720       690       630       12   12

                                                                                                                              –710         790       765      710        10   14

                                                                                                                              –800         880       850      800        10   14

                                                                                                                              –900      1000         970      900        16   14

                                                                                                                             –1000      1080     1050         1000       16   14
Flexible connection, inlet                                   Duct connection

                                                               CNA                                                                                                       Weight
                                                                              A           B         D1            D2          L         P            R             X
                                                               CNB                                                                                                        kg
                                                               -250           377         355        315          250         150           8            10        70         10
                                                               -315           482         450        400          315         195           8            12        87         12
                                                               -400           592         560        500          400         215          12            12        111        16
                                                               -500           722         690        630          500         284          12            12        138        25
                                                               -630           893         860        800          630         365          16            12        174        45
                                                             The inlet vane control is mounted direct on the inlet spigot of the fan.
                                                             Use an inlet flange for attachment of flexible connection.
Conical
                                                             Performance curves (pages 142-146) apply to fans without inlet vane control.
inlet vane control for
                                                             NB: Do not forget control.
sizes -250 to -630.


                                                                  CNA                                                                                                    Weight
                                                                                      A             B              D                L            P             R
                                                                  CNB                                                                                                     kg
                                                                        –710           800           765               715           250             10         14            56
                                                                        –800           880           850               800           250             10         14            74
                                                                        –900          1000           970               900           350             16         15            91
                                                                      –1000           1090         1050            1000              350             16         15            100
                                                             The inlet vane control is mounted on the fan by means of an inlet flange.
                                                             Use an inlet flange for attachment of flexible connection.
                                                             Performance curves (pages 142-146) apply to the fans without inlet vane control.
QBA
inlet vane control for
sizes -710 to -1000.


Owing to continued product development Novenco reserves the right to introduce alterations without prior notice                                  CNA            141
Centrifugal fans type CNA
Performance curves

CNA–250
ρ =1.20 kg/m3
Iv = 0.025 kgm2

Impeller tip speed
u =0.013 x n, m/s.




                       pt, Pa




CNA–315
ρ =1.20 kg/m3
Iv = 0.05 kgm2

Impeller tip speed
u =0.016 x n, m/s.
                       pt, Pa




 Sound data:                    Symbols:
 Please see page 147            pt = total pressure                                        qv     =     volume flow
                                pd = dynamic pressure, outlet                              n      =     speed, r.p.m.
                                p1 = connection loss, inlet                                η      =     efficiency, %
                                p2 = connection loss, outlet                               kW     =     power required, impeller
                                v  = air velocity, outlet                                  dB     =     sound power level, outlet




        142 CNA                   Owing to continued product development Novenco reserves the right to introduce alterations without prior notice
Centrifugal fans CNA and CNB
Performance curves

CNA–400
max.       = 1950 r.p.m.
Iv         = 0.175 kgm2


CNB–400
max.       = 2380 r.p.m.




                                                      pt, Pa
Iv         = 0.3 kgm2


Impeller tip speed
u          = 0.021 x n, m/s.
ρ          = 1.20 kg/m3




CNA–500
max.       = 1575 r.p.m.
Iv         = 0.55 kgm2


CNB–500
max.       = 1925 r.p.m.
Iv         = 0.75 kgm2
                                                       pt, Pa




Impeller tip speed
u          = 0.026 x n, m/s.
ρ          = 1.20 kg/m3




 Sound data:                                                    Symbols:
 Please see page 147                                            pt = total pressure                               qv   =   volume flow
                                                                pd = dynamic pressure, outlet                     n    =   speed, r.p.m.
                                                                p1 = connection loss, inlet                       η    =   efficiency, %
                                                                p2 = connection loss, outlet                      kW   =   power required, impeller
                                                                v  = air velocity, outlet                         dB   =   sound power level, outlet




Owing to continued product development Novenco reserves the right to introduce alterations without prior notice                CNA      143
Centrifugal fans CNA and CNB
Performance curves

CNA–630
max.    = 1240 r.p.m.
Iv      = 1.35 kgm2


CNB–630
max.    = 1515 r.p.m.
Iv      = 1.85 kgm2




                            pt, Pa
Impeller tip speed
u       = 0.033 x n, m/s.
ρ       = 1.20 kg/m3




CNA–710
max.    = 1105 r.p.m.
Iv      = 3 kgm2


CNB–710
max.    = 1350 r.p.m.
Iv      = 3 kgm2
                            pt, Pa




Impeller tip speed
u       = 0.037 x n, m/s.
ρ       = 1.20 kg/m3




 Sound data:                         Symbols:
 Please see page 147                 pt = total pressure                                        qv     =     volume flow
                                     pd = dynamic pressure, outlet                              n      =     speed, r.p.m.
                                     p1 = connection loss, inlet                                η      =     efficiency, %
                                     p2 = connection loss, outlet                               kW     =     power required, impeller
                                     v  = air velocity, outlet                                  dB     =     sound power level, outlet




        144 CNA                        Owing to continued product development Novenco reserves the right to introduce alterations without prior notice
Centrifugal fans CNA and CNB
Performance curves

CNA–800
max.       = 975 r.p.m.
Iv         = 5 kgm2


CNB–800
max.       = 1190 r.p.m.
Iv         = 5 kgm2




                                                      pt, Pa
Impeller tip speed
u          = 0.042 x n, m/s.
ρ          = 1.20 kg/m3




CNA–900
max.       = 870 r.p.m.
Iv         = 7.75 kgm2


CNB–900
max.       = 1065 r.p.m.
                                                      pt, Pa




Iv         = 7.75 kgm2


Impeller tip speed
u          = 0.047 x n, m/s.
ρ          = 1.20 kg/m3




 Sound data:                                                   Symbols:
 Please see page 147                                           pt = total pressure                                qv   =   volume flow
                                                               pd = dynamic pressure, outlet                      n    =   speed, r.p.m.
                                                               p1 = connection loss, inlet                        η    =   efficiency, %
                                                               p2 = connection loss, outlet                       kW   =   power required, impeller
                                                               v  = air velocity, outlet                          dB   =   sound power level, outlet




Owing to continued product development Novenco reserves the right to introduce alterations without prior notice                CNA      145
Centrifugal fans CNA and CNB
Performance curves

CNA–1000
max.    = 785 r.p.m.
Iv      = 14 kgm2


CNB–1000
max.    = 960 r.p.m.




                            pt, Pa
Iv      = 14 kgm2


Impeller tip speed
u       = 0.052 x n, m/s.
ρ       = 1.20 kg/m3




 Sound data:                         Symbols:
 Please see page 147                 pt = total pressure                                        qv     =     volume flow
                                     pd = dynamic pressure, outlet                              n      =     speed, r.p.m.
                                     p1 = connection loss, inlet                                η      =     efficiency, %
                                     p2 = connection loss, outlet                               kW     =     power required, impeller
                                     v  = air velocity, outlet                                  dB     =     sound power level, outlet




        146 CNA                        Owing to continued product development Novenco reserves the right to introduce alterations without prior notice
Centrifugal fans CNA and CNB
Sound conditions                                            calculations of sound conditions in                          sound absorbing properties of the
The operation of a fan will inevitably                      the duct systems and the spaces                              surroundings are identical in both
be attended with the generation of                          served by the fan.                                           cases.
sound. The sound will be produced
by the motor, the bearings, and other                       The Sound Pressure Level (often just                         In a correctly designed fan the sound
mechanical components, as well as                           called sound level) is a term de-                            power level depends almost exclus-
by the passage of air through the fan.                      scribing the sound impression per-                           ively on the quantity of air supplied
                                                            ceived by the ear at a given distance                        and the total pressure of the fan.
This sound can be kept within                               from the fan; it is measured by
bounds by careful design and con-                           means of a sound level meter, which                          The sound power level of the indi-
struction of all components of the                          has a microphone placed at the point                         vidual fans will appear from the per-
fan – as far as air generated sound is                      in question.                                                 formance curves on pages 142-146.
concerned it is especially the inlet                                                                                     The sound power level, indicated in
cone and impeller that require atten-                       The sound pressure level depends                             terms of dB ref. 10-12 W, applies to
tion. In this connection it should be                       on the sound power level, the dis-                           the normal field of operation of the
borne in mind that adverse installa-                        tance from the fan, and the sound ab-                        fan, subject to a tolerance of ± 5 dB.
tion conditions, for instance sharp                         sorbing properties of the surround-                          If the sound power level is to be di-
bends immediately in front of the in-                       ings.                                                        vided into octave values, the sound
let opening, can increase the sound                         When describing the acoustic prop-                           power level within the individual
generation considerably.                                    erties of a fan by reference to a sound                      octave bands can be determined by
                                                            pressure level it will therefore be                          subtracting the correction values
The sound generated by motor and                            necessary at the same time to give an                        listed in the below table from the to-
machinery as well as the part of the                        accurate description of the condi-                           tal sound power level found.
air-generated sound passing                                 tions under which this sound pres-
through the fan casing can only be                          sure level will occur.                                       For CNA and CNB the correction
reduced by surrounding the fan with                                                                                      values depend on the blade frequen-
                                                                                                                                 n
an enclosure or walls of vibration re-                      When evaluating the acoustic prop-                           cy z × ----- where z is the number of
                                                                                                                                60
                                                                                                                                    -
tarding (heavy) materials.                                  erties of two fans, never compare a                          blades and n the fan speed in r.p.m.
                                                            sound power level with a sound                               For CNA and CNB the number of
The sound generated in the impeller                         pressure level, and when comparing                           blades is 12.
is transmitted through the fan inlet                        two sound pressure levels make sure
and outlet to the ducting and thence                        that the distance from the fan and the
to the ventilated spaces. Any calcu-
lation of sound conditions in the                            Correction values
duct system and the ventilated spac-                               Octave band, Hz                   63       125       250   500    1k       2k    4k    8k
es - as well as the design of anti-vi-                                           90-180 Hz                7        4      7    12      17     22     27     32
bration mountings, if any, to be in-                          CNA, CNB          180-360 Hz             11          7      4     7      12     17     22     27
stalled in the system – must be based                           Blade-
                                                                                360-710 Hz             13         11      7     4         7   12     17     22
                                                              frequency
on the sound power level in the fan                                            710-1400 Hz             15         13     10     6         4    7     12     18
inlet and outlet.
                                                            Example: A centrifugal fan type                             The correction value for 250 Hz is 4
In dealing with sound problems it is
                                                            CNA-315 delivers 0.6 m3/s against                           dB. Accordingly the sound power
essential that a sharp distinction be
                                                            300 Pa at 1400 r.p.m. Blade frequen-                        level of this octave band will be 85 dB
made between sound power level
                                                            cy: 12 x 1400/60 = 280 Hz. It will ap-                      – 4 dB = 81 dB. The complete octave
and sound pressure level.
                                                            pear from the chart on page 142 that                        band analysis is given in the table
                                                            the total sound power level is 85 dB.                       below.
The Sound Power Level, a term de-
scribing the sound energy trans-
                                                                   Octave band, Hz                     63         125   250   500      1k     2k     4k     8k
mitted through the fan inlet and out-
                                                               Sound power level, dB                   74          78    81    78      73     68     63     58
let openings, forms the basis of all


Owing to continued product development Novenco reserves the right to introduce alterations without prior notice                           CNA      147
Control of air quantity
Dependent on the operating require-                         vide the fan with a pole-changeable                           The inlet vane control can be op-
ments the fan capacity can be con-                          motor. When changing to another                               erated by a servomotor which is con-
trolled in several ways:                                    speed the fan efficiency will remain                          trolled by a pressurestat or a flow-
– By means of pole-switching be-                            unchanged.                                                    sensor.
   tween 2 fixed fan speeds in the                          The pole-changing can be controlled                           At reduced flow control the fan effi-
   proportion 3 : 2 (motor with 2                           by a timer.                                                   ciency will drop as indicated on the
   separate windings) or 2 : 1 (motor                       If other operating points are re-                             performance chart. In case of large
   with Dahlander windings).                                quired than those obtainable by                               air quantity variations it is therefore
– By means of inlet vane control on                         pole-changing other methods of                                recommended to combine the inlet
   the inlet side of the fan.                               control must be applied.                                      vane control with pole-changing.
– By means of speed control
   through frequency conversion.                            Inlet vane control                                            Frequency conversion
– By means of a combination of the                          In systems with continuously                                  Used under the same operating con-
   above solutions.                                         changing air quantity requirements                            ditions as for an inlet vane control,
                                                            or in systems where the air quantity                          the fan efficiency will almost remain
Pole-changing                                               must be constant irrespective of out-                         unchanged in the entire downwards
In case of varying air quantity re-                         side pressure conditions, an inlet                            controlled area and no additional
quirements (e.g. at night and day                           vane control can be used.                                     sound is generated during the
operation) it is recommended to pro-                                                                                      downwards control.




                                                                  8 0%
                                                              7 0%
Total pressure, Pa




                                                         60
                                                              %

                                                      50%

                                                   40%

                                            3 0%                                                   90˚
                                                                                             70˚
                                                                                          70˚
                                          20%                                       60˚
                                                                              50˚
                                     10%                           40˚
                                                              30˚ Aperture
                                                20˚
                                    10˚

                                       Air quantity, qv
                     Principle diagram showing relation between aperture angle and
                     efficiency when downward controlling with inlet vane control.




                      148 CNA                                     Owing to continued product development Novenco reserves the right to introduce alterations without prior notice

								
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