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The Dalby is an side entry lantern for 60/200W tungsten, GLS or 80/125W mercury
discharge lamps types MB/U or MBF/U.
Aluminium alloy has been chosen for the common basic metal to take advantage of its inherent
corrosion resistance and light weight leading to long service life and ease of handling during
installation.
Application
Group 'B' roads. Pedestrian walkways and Residential areas.
Specification
The lantern complies with BS 1788 for streetlighting lanterns.
The canopy consists of a one piece aluminium alloy pressing with a highly specular
anodised interior. The plan shape is elliptical to redirect the major portion of light flux
along the road axis.
Weatherproof protection for the lamp and optical system is obtained by a patterned perspex bowl.
The enclosing bowl includes a stainless steel hinge at the roadway end and can be completely removed
for cleaning. At the bracket end, the bowl is secured to the canopy by a captive nylon finger
screw. The seal between the bowl and the canopy is maintained by a hollow section neoprene gasket
allowing easy compression and a reduction in the stressing of the hinge and fastening.
Commection between the lantern body and the mounting bracket is made by two LM6 aluminium castings.
The internal casting is also utilised as a cable clamp, earth terminal and lampholder fixing.
Mounting
The lantern is arranged for side entry ¾" BSP plain, and is secured to the bracket arm by 'Allen'
screws located externally. Details of Leader columns and brackets are given on separate leaflets
SE 460 Ed B and SE 520 Ed A.
An alternative mounting arrangement is provided with a wall mounting box and bracket. The
box is cast from LM6 aluminium alloy and is fitted with a IROKO hardwood baseboard for securing
the electrical central gear with provision for time switches, fuses, cut-outs, etc.
Wall fixing bolts pass through bosses inside the box and are protected from weather.
The boxes are raised above the baseboard to allow for movement of the wood during
varying climatic conditions. Fitting pads on the rear face cater for uneven
wall surfaces.
A ribbed door of NS4 aluminium fitted with a stainless steel lock encloses the box.
When unlocked the door can be swung through 180o and relocked in the underhung
position for inspection or maintenance.
The outreach bracket is of extruded aluminium tube, approx 14" long for ¾" BSP
plain.
A post top version of the Dalby lantern with complete details are given on leaflet
AF 356.
Weight
Dalby side entry 4¼ lb.
Wall box 9½ lb.
Bracket ½ lb.
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