holophane bowl type refractors
2-way non-axial (160°)
Holophane Two-Way Bowl Refractors are similar in size and mechanical construction to the standard symmetrical
types, but the prism formation is designed to concentrate the light rays in two main directions instead of symmetrically around the unit.
This Two-Way concentration gives higher intensities than those obtained with the standard type and therefore permits of wider spacing
with equivalent uniformity of illumination.
This type distributes the two main beams at an angle 160 degrees horizontally, the maximum candle power being given from 70 to 80
degrees from the vertical in two directions, therefore should be used when the units are installed at the side of the road,
and between street intersections.
* From centre of filament to top of glass
Vertical Candle Power Distribution Curve.
Lobes 160° Apart Horizontally.
Plan Candle Power Distribution Curve.
Through a 80° Cone.
Holophane 2-Way Refractors should be installed where the width of the street does not exceed 80 feet and the spacing ratio,
distance apart to height, is from 8-1 to 12-1.
It is important that the lamp filament takes up the correct position relative to the refractor. These positions are given
in detail on Page 13.
Holophane Lanterns illustrated on Pages 28 to 30 are designed with a special focussing device to enable the lamp to be adjusted in
position and also with special projections in the band so that the refractor must be fitted in the correct relation to the lantern
for proper orientation with reference to the street.
Recommended intensities for the various classes of thoroughfares will be found on page 4.
Table of Lumens required per lineal foot of street, with the Lumen rating of Gas Filled lamps will be found on
Pages 15 and 16.
"HOLOPHANE, SOWEST, London"
"VICTORIA, 2491, 8258."
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