Line Material Industries Early Style Ovalite (tm) Luminaire

Line Material Industries of Milwaukee, Wisconsin gave the name "Ovalite" to their first model of streetlight designed for mercury vapor lamps.

Line Material had a much smaller market share compared with General Electric and Westinghouse. For those familiar with the then common GE Form 109 mercury streetlight, the early style Ovalite has a similar format. The head (with mounting collar) is of cast aluminum and is like a top cap. The one piece stamped aluminum reflector and the glass refractor mounted below form an enclosed globe with a somewhat rectangular shape as seen from below.

Early style Ovalite, exterior

The early style Ovalite appears to have been also suited for incandescent lamps. This made it attractive for cities installing new streetlighting but wishing to delay the use of mercury vapor lighting, perhaps until the budget allowed for that.

1.  There is a large opening in the top of the reflector to accommodate the neck of an incandescent lamp. (For mercury lamps a reflective panel covers part of this opening.)

2.  There are mounting holes (currently unused) in the head positioned for a socket that would hold the lamp vertically, base-up, which is the optimum position for an incandescent lamp. The fixture is intended to hold mercury lamps horizontally.

3.  There is a seemingly useless fin cast as part of the fixture head. Such a fin would act as a heat sink perhaps allowing the use of up to 600 watt (620 watt) 10,000 lumen incandescent lamps. This capability would be needed to compete with the GE Form 109 which also fit the needs of cities installing streetlights but converting to mercury vapor later. The standard mercury vapor lamps  in use then were rated for 250 or 400 watts, the latter delivering 20,000 lumens..

Early style Ovalite, interior

Unlike for the GE Form 109, the reflector is bolted rigidly to the head. Access to the inside is had by removing the refractor. Although the two clasps for the refractor are the same, either one can be unfastened and the refractor will hang safely from the other while the lamp is changed or other servicing done inside.

The rectangular-ish shape of the body (as seen from below) suggest that some engineering was done to distribute more light up and down the street as opposed to in a simple circular pattern.

The approximate dates of manufacture are late 1940's to early 1950's. Line Material then introduced a clamshell style of fixture for mercury lamps and used the same name, Ovalite, for it.

Dimensions: 19-1/4" long by 14-5/8" wide overall.

Weight: 23 lb. not including lamp.

Last updated 2/16/12

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