Argus I for Group 'B' Roads
Single piece dome refractor lantern with outer bowl
Crompton Lamps :-
| 60/200W. | Tungsten filament | (GLS) |
| 80/125W. | Mercury Electric Discharge | (MB/U) |
| 80/125W. | Mercury Fluorescent Discharge | (MBF/U) |
With an outer bowl to seal the interior against dust and weather, this simple but robust lantern
embodies the following features:-
- Automatic focusing of lamp and registration of refractor.
- Totally enclosed quick release clips for removal of refractor.
- Outer bowl available in glass or 'Perspex'
- Internal single piece refractor in three distributions.
|
|
| 60/200 GLS | B.C. | S121AS | S121AN | S121AX |
| 60/200 GLS | E.S. | S121BS | S121BN | S121BX |
80/125 MB/U
80/125 MBF/U | 3-pin B.C. | S121CS | S121CN | S121CX |
For 'Perspex' instead of glass outer bowl add suffix 'P' e.g. S121 AS/P.
Unless otherwise specified standard ¾ B.S.P. tapping will be supplied. |
| Dimensions, Tapping & Height |
| Height | 12 5/8" |
| Diameter | 12" |
| Tapping B.S.P. | ¾ |
| Minimum length of thread required | 7/8" |
| Weight | 8 ¾lbs. |
| Refractor Catalogue Numbers |
| Symmetrical | 4116 |
| Non-Axial | 2/4116 |
| Axial | 22/4116 |
1. Construction
The skirt is cast with the body which is arranged for top entry and provided with three sets of tapped bosses for
the fixing of the lampholder bridge assembly. This consists of a simple bridge piece, carrying the lampholder,
with bayonet slots to engage fixing screws in the bosses. The bayonet slots allow the bridge to be change from one
set of bosses to another or to be removed for wiring without the complete withdrawl of the fixing screws.
The body has two totally enclosed spring loaded clips for the retention of the refractor glassware. This is of the single
piece dome type with prisms moulded on both its internal and external surfaces. A projection moulded on the neck of
the refractor engages with a recess in the body casting and ensures correct angular location.
The outer bowl, which is held in position by three substantial fixing clips, is carried in a hinged retaining ring and
is effectively sealed against the ingress of dust by two gaskets. Lugs on the ring engage with a self retaining wing
nut fastening fitted to the lantern body.
2. Material And Finish
| Body | Silicon aluminium alloy LM6M, exterior finish aluminium, interior finish white |
| Refractor | Crystal glass |
| Outer bowl | Clear glass or 'Perspex' |
| Bridge piece | Mild steel cadmium plated |
| Hinge screws | Stainless steel |
| Wing nuts | Brass cadmium plated |
| Internal screws | Mild steel cadmium plated |
3. Distribution
Typical Polar Curves and an Iso-Candle diagram for the most popular 2/4116 non-axial refractor are given in Figs. 1 and 2.
FIG. 1
Polar distribution for 2/4116 refractor with 200W 2725-lumen lamp
A: In vertical plane through the centre of the main beam
B: Plan distribution of 80° cone
FIG. 2
Iso-candle diagram for 2/4116 refractor with 200 W. 2725-lumen lamp.
4. Focusing
The bosses to which the lampholder bridge should be fixed for each lamp size are clearly marked within the lantern.
5. Maintenance
The aluminium alloy from which this lantern is cast is highly resistant to corrosion in both industrial and marine atmospheres.
Additional protection can be provided by occasional painting in service.
6. Optical Data For 2/4116 Refractor
| G.L.S. | MB/U |
| Beam Angle Horizontal | 170° | 170° |
| Beam Angle Vertical | 80° | 80° |
| Light output ratio | 77% | 76% |
| Light flux in lower hemisphere | 86% | 86% |
| Directional Intensity Ratio | 3.9 | 2.9 |
|
