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mj, , Donkin Fans

Majax-2 Aerofoil Axial Flow Fans

- IW '~AJAX-2 GENERAL SPF ~IFICATION

Majax-2 axial flow fans are manufactured in diameters ranging from 315mm to 2000mm (available in 2250mm on request), and incorporate manually adjustable pitch aluminium bladed impellers. The following configurations are available: - Direct driven units with the impellers attached directly onto the

shafts of totally enclosed motors mounted directly in the airstream.

- Belt-driven units w ~ t h the motors mounted out of the airstream on the outside of the fan casings.

- Bifurcated units with motors mounted in bifurcations, out of the airstream.

- BELLAX fans with impellers attached directly onto the shafts of totally enclosed motors and mounted on fibreglass plates with bell shaped entries.

- Majax-2 Plate mounted with the impellers attached directly onto the shafts of totally enclosed motors and mounted on carbon steel plates.

- Vertical jet, roof mounted extraction units, available in two ranges (HVJ-2 & HVJ-2s). See roof unit brochure for further information.

APPUCATlONS This range of fans is ideally suited for moving large volumes of air against low and medium pressures in the following applications: - General ventilation: kitchen canopies, supermarkets, airport

buildings, underground car parks, stairwell pressurization, gymnasiums and stadium cloak rooms, industrial buildings, etc.

- Air-conditioning. - Smoke control and exhausting heat from buildings. - Condenser cooling. - Cooling towers. Combinations of motor speeds, impeller blade pitch settings, and the number of blades per impeller (full and half solidity), provide flexibility in terms of selection. Fans offering good efficiencies can be selected over a range of volumes from 0,l m3/s to 85m31s at total pressures up to 1,O kPa.

SUES The MAJAX-2 range is available in the following sizes: - Standard direct drive fans in 12 sizes:

from 315mm to 2000mm (available in 2250mm on request). - Standard belt drive fans in 11 sizes:

from 400mm to 2000mm. - Bifurcated fans in 7 sizes:

from 400mm to 1250mm. - BELLAX in 7 sizes:

from 315mm to 1000mm. - Plate mounted axial fans in 8 sizes:

from 400mm to 1000mm. - Vertical jet roof units:

HVJ-2 in 3 sizes from 630mm to 1000mm. HVJ-2S in 7 sizes from 400mm to 900mm.

Sizes vary in accordance with the preferred increments covered in IS0 497- 1973 (E) R2O. The sizes are: 315,400,500,560,630, 710, 800,900, 1000,1250,1600,2000 and 2250.

IMPELLERS Impellers Incorporate die-cast aluminium alloy blades of aerofoil section, which are clamped in split steel hubs (Majax-2 1250H impellers have spl~t aluminium cast hubs). Blade pitch adjustment is achieved by slackening the hub clamping bolts and sett~ng the blades to the required pitch prior to re-tensioning the clamp bolts.

IMPELLER FINISH Majax-2 315-1000 and 125QF hubs are electro-coated, Majax-2 1250H hubs are aluminium cast. Majax-2 1600 to 2250 hubs are fabricated and hot dip galvanised. Aluminium sutface finishes are left natural. All fasteners are zinc plated.

BALANCING Impellers are dynamically balanced to IS0 1940 grade C6.3.

CASINGS - DIRECT DRIVE Standard casing lengths (SL) usually cover the impeller and motor assemblies. External terminal boxes are provided on the casings of fans fitted with standard totally enclosed motors (see brochure for connection details). Where flame-proof motors are fitted, a length of armoured cable, which passes through the fan casing, is connected to the motor. The free ends of these cables are to be connected to fittings appropriate to the installation. Smoke extraction fans are fitted with external, certified terminal boxes and conduit for the selected application. Casings incorporate viewing ports unless access panels are provided.

CASINGS - BELT DRIVE Standard casing lengths cover the overall length of the impeller and belt drive assemblies. Generally, motors would not project beyond the casing flanges. Standard belt drive fans incorporate casing access panels,

FLANGE DIMENSIONS AND DRllLlNGj Flange dimensions and drllllngs are In accordance w ~ t h BS 6339. See brochure for details.

CASING FINISH Casings are hot-dip galvanized to IS0 1461. All fasteners are zinc

>. plated.

MOTORS Up to frame size 160, pad mounted motors are used in most direct driven fans. For all other applicat~ons foot mounted motors are used. Both pad and foot mounted motors are totally enclosed. Minimum protection is IPS5 for pad and foot mounted motors. Standard motors have Class F insulation. Standard voltages are 400 volt three phase and 2201230 volt single phase, 50Hz. Electrical performance complies with IEC 34. Motors with non-standard classes of insulation, special grease for highllow temperature operation, flameproof construction, special voltages, multi-speed, etc., may be available on application.

MOTOR SUPPORTS Direct driven fans up to size 1000, driven by pad mounted motors up to frame 132, have motors mounted in plates suspended in rubber mountings to minimize noise and vibration. All other pad mounted motors are mounted by means of support rods.

Belt driven fans utilize foot mounted motors fitted to motor supports mounted externally on the fan casings.

DlRECnON OF AIR FLOW Forms B, BD and BU are standard arrangements for direct drive fans, having motors mounted downstream of the fan impellers.

Forms A, AD and AU are standard arrangements for belt drive fans, having the bearing and drive assemblies mounted upstream of the

,, , fan impellers. These forms can also be used on direct drive fans. Mechanical details and bearing selections on all MAJAX-2 fans, whether direct or belt drive, are suitable for any of these attitudes. However, impellers require changing from Form A to Form B running.

fi BEARING LIFE (LIO) Direct driven 2 pole units are designed to have a 20 000 hour statistical bearing life, and 4,6 and 8 pole units are designed to have a 40 000 hour statistical bearing life. Belt driven units are designed to have a statistical 40 000 hour bearing life.

TEMPERATURE LIMITATIONS MAJAX-2 fans are suitable for operating within the following temperature ranges: - Standard direct drive fans: - 20°C to + 50°C. - Standard belt drive fans: - 10°C to + 50°C. - Bifurcated fans: - 20°C to + 200°C.

/- -. - BELLAX: - 20°C to + 50°C. Impellers from 500 to 1000 have been successfully tested in accordance with BS 7346 : Part 2: 1990 at 300°C for 2 hours. Impeller diameter 1600 has been successfully tested in accordance with BS 7346: Part 2: 1990 at 300°C for 1 hour.

MOISTURE TREATMENT Standard fans are suitable for continuous operation in relative humidities up to 95%. Special treatment of fans is available to render them suitable for continuous operation in moisture laden atmospheres. This treatment involves additional mechanical and electrical sealing procedures.

PERFORMANCE ~ l l performance data is based on tests carrlea out In accoraance with BS 848: Part 1 - Test method No. 1. Ratings are based on standard air density of 1,20kg/m3 corresponding to an air temperature of 20°C, a barometric pressure of 101,325 kPa and a relative humidity of 62%. Power values given reflect fan shaft power without provision for drive losses.

SOUND DATA The sound data indicated on the performance graphs are "In-duct" values obtained from tests conducted in accordance with BS 848: Part 2 - In-duct method. The higher values on the Sound Level contours are Overall Sound Power Levels (suffixed dBW), and the lower values are Average Sound Pressure Levels, under free field conditions, at adistance of 3 impeller diameters from the fan inlet or outlet. Sound Power Levels are given in decibels re: 10-12 Watts. Sound Pressure Levels are given in decibels re: 2 x 10-5 Pa. An octave band analysis can be obtained by subtracting the spectrum constants, tabulated on each performance graph, from the Overall Sound Levels. A-Scale levels are obtained by subtracting an A-Scale correction constant, given on each performance graph, from the Overall Sound Level. "Free-field sound levels incorporating inlet/outlet end reflection losses, are obtained by subtracting the following constants from the "In-duct" Octave Band Sound Levels.

REVERSAL OF At, m d W The direction of air flow of a standard impeller can be reversed by changing the direction of fan rotation. Equal volume flow in either direction can be provided by means of special blade adjustments. The approximate resultant fan performance for the above conditions when compared with standard fan performance is as follows:

STANDARD REVERSIBLE I IMPELLER I IMPELLER I , Power Reduction I

OPTIONAL FEATURES Mounting feet, counter flanges, wire screens, conical inlets, anti- vibration mountings, casing access panels & flexible connections. Hand, motor or airstream operated dampers. Cylindrical attenuators of matching sizes. Non-standard casing lengths & special protective coatings. Belt guards & belt fairings (belt drive fans).

All technical information contained herein is subject to change without prior notice.

B F HOLES 0 G 7 LIFTING LUCI* 'i

I DIA. J HOLE FOR CONDUIT ENTRY --I

FAN MASS = K

DIRECT DRWE BELT DRIVE

All technical information contained herein is subject to change without prior notice.

FAN DIRECT DRIVE BELT DRIVE Mass Mass SIZE FAN SPEED (rpm) - MOTOR POWER (kW) MOTOR POWER B C D F G H I J K L

NLET C< -

AN MOUNTING FOOT

OUTLET DAMPER

All technical information contained herein is subject to change without prior notice.