Z.9443 lantern. Sectional scale drawing. The iso-candle is based on an average lamp light output through life from a 85 watt OSRAM Sodium lamp. (4,850 lumens) . 85 w. Directional intensity ratio 3 Light above horizontal nil Light output ratio 65%

CUT-OFF LANTERN for OSRAM SODIUM LAMPS Lantern seen from underneath with lampholder compartment opened showign focusing arrangement.

Cut-off Lantern for large Sodium Lamps.

Use Main road lighting, roundabouts, roads in the vicinity of airfields, dock and waterside lighting. This lantern has a cut-off distribution and no light is emitted above the horizontal. The peak candle power is at about 70 deg. to the vertical and above this angle the intensities fall off very rapidly, therefore lanterns should be mounted at 25 ft. and spaced not more than 95-100 ft. apart. Best results are generally obtained by using some form of central suspension, provided that the road width does not exceed about 45 ft.

These characteristics make the lantern suitable for waterside lighting where, for navigational purposes, it is generally necessary for lights to be shielded.

It has also been found tht cut-off lighting gives the best visibility at roundabouts where normally the number of lanterns that can be seen may cause confusion.

Lamp Z.9443. For use with 85 w. or 140 w. OSRAM lamp.

Mounting Two clamps on the lantern roof secure it to the horizontal bracket arm which must be a minimum length of 14 in. Bracket tubing of ¾ in. - 1½ in. gas, unthreaded, can be used.

Lampholder Porcelain B.C. lampholder. This is housed in a separate compartment with a sliding cover underneath; an earthing screw is provided.

Lantern Body The body is of copper with a cable entry elbow on the lampholder compartment. The lamp steady provided is suitable for both the 85 w. or 140 w. lamp. The steady is reversible allowing for either lamp. A stainless steel spring is provided to ensure that the lamp is held firmly in the steady.

Focusing The holder is mounted on a sliding platform. This enables the angle of cut-off, and therefore the angle of peak candle-power, to be varied. The correct positions for these different angles is marked.

Optical System
Two curved glass mirrors are fixed inside the body, to provide the main light control. There are also flat mirrors on the inside of each of the lantern ends. All mirrors are copper and lead-backed and secured by clips.

Weathering Finish The lantern is finished a matt aluminium stove enamel externally and white enamel internally.

Erection Instructions Full erection and focusing instructions are packed with each lantern.

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