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Clearside 9480/1A And 9490/1A Lanterns
For Osram Sodium Lamps

Specification Clearside 9480/1A & 9490/1A

Side road lighting, especially in the vicinity of airfields. The lantern is designed for mounting at 13-15 ft (3.96-4.57 m) and spacing at 100-120 ft. (30.48-36.55 m.) Road width up to 30 ft (9.14 m).

The lantern falls within the specification issued by the Ministry Of Transport for street lighting lanterns to be used in the vicinity of airfields.

45W or 60W Osram integral jacket sodium lamp type SOI/H or detachable jacket sodium lamp type SO/H.

The Z9480'A' or Z9490'A' side entry lantern requires not less than 3 in. (76.2 mm) of horizontal unthreaded 1 in. B.S.P. When fully home, two 7/16 in. diameter Allen type grub screws grib the barrel. Water running along the bracket arm is prevented from entering the lantern by a water baffle.

The Z9481'A' and Z9491'A' top entry lanterns are tapped 3/4 in. B.S.P. and are supplied with a locknut.

Lantern Body
One piece light alloy die-casting. In the Z9480'A' and Z9481'A' lanterns the inner surface of the body is white enamelled to act as an over-reflector. The bodies carry a lamp steady and lampholder wired with heat-resisting insulated wire to a porcelain terminal block. An earthing screw and porcelain cable cleat are provided.

In the Z9490'A' and Z9491'A' lanterns the body is fitted with a transformer and power factor correction capacitor, which are screwed onto bosses in the casting. Covering the gear is an over reflector finished in glossy synthetic white enamel. The over-reflector carries the lamp steady. The lampholder is wired with heat resisting insulated wire to the terminal block on the transformer. Provision for fuses can be made if required.

Porcelain B.C. The lampholder position is fixed.

Optical System
Light control is provided by two 'Diakon' injection moulded refractor plates. The prismatic plates are recessed into each side of a 'Diakon' injection moulded bowl. Injection moulding has many advantages over conventional methods of manufacture. It provides a very high degree of repetitional accuracy, more efficient light control by the highly finished prisms, has great impact resistance and is light in weight.

Screening from the air is achieved by a moulded 'Perspex' box cemented on each side of the bowl over the refractor plates. Each box contains 'Perspex' louvres, silvered on both surfaces.

Both inner and outer surfaces of the optikon are smooth for easy cleaning.

The ends of the bowl are silvered on the inside. The bowl is attached to the lantern body by means of two stainless steel hinges and fastened by a neat but robust stainless steel toggle catch. The bowl can be lifted off the hinges, if required, to facilitate cleaning. A tropicalised felt gasket between the bodycasting and bowl ensures a weatherproof seal when the lantern is closed.

Weathering Finish
The alloy used is specially selected for its resistance to corrosion and processed to give a pleasing appearance.

The Z9490'A' side entry lantern with the bowl lowered showing the lamp arrangement and the over-reflector covering the lamp operating gear.

The iso-candela diagram is based on an average lamp life from a 60W Osram integral sodium lamp (3,420 lumens average).

Directional intensity ratio2.06:1
Light above horizontal2%
Light output ratio71%
Lumens in the lower hemisphere    2260    

Light distribution data are given for the guidance of the lighting engineer and represent the average results of laboratory tests on a number of lanterns taken at random from stock. The data are based on the tube characteristics stated; if the latest tube efficiency is different, the candela or lumen values should be calculated in direct proportion to the relative tube lumens.

Lantern weights: Z9480'A': 12lb (5.4 kg)
Lantern weights: Z9481'A': 11lb (5 kg)
Lantern weights: Z9490'A' Complete with gear: 22lb (10 kg)
Lantern weights: Z4991'A' Complete with gear: 21lb (9.5 kg)