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1945 Theatre Catalog, 4th Edition, Page 522 (496)

1945 Theatre Catalog, 4th Edition
1945 Theatre Catalog
1945 Theatre Catalog, 4th Edition, Page 522
Page 522

1945 Theatre Catalog, 4th Edition, Page 522

STERILAMPS are long, slender glass tubes made of special glass and operating on the gaseous discharge principle. Pictured here are the common sizes of Sterilamps of the hot-cathode type. Over 80 per cent of the radiant energy given at? by Sterilamps is bactericidal. While invisible to the human eye, it kills viruses, bacteria, and molds. For air-duct installation, it is the cold-cathode lamp of comparable characteristics that is usually used.

larly, the dimensions are usually sufficient to house all of the lamps without alteration. Convenience is still another reason for selecting the plenum chamber if possible. It permits easy access for cleaning, testing, and replacement. The other general location for Sterilamps is in the air ducts, where two possibilities are open. Of these, the delivery duct-between the fan and the first outlet branch-is preferred,- since the combined fresh and recirculated air

can be sanitized at the same time. Sterilampslcan also be housed in the return duct, just before the air passes into the plenum chamber. In this location, the radiation is not directed on the fresh air. However, fresh air approaches the maximum freedom from disease-producing bacteria and it is, therefore, not essential that this air be irradiated. The proper installatiion of germicidal lamps in air-conditioning ducts requires considerable care. In either duct loca THE COMPLETE LINE of cold-cathode Sterilamps is pictured here. These lamps, burning at low temperatures, do not add additional load to the air-conditioning system. They operate on the usual llO-volt, 60-cycle, a.c. circuits.

The lamps are long lived, being able to be burned continuously for six months, or intermittently for approximately 4,500 hours. The lamp does not burn out, although it does in time lose etticiency, and so it has to be replaced.







tion, the section should be straight, so that radiation can be effective as the air stream approaches and after it has passed the lamps. Also, the longer the duct the more desirable the location, since, with the more distant spacing the fewer Sterilamps are needed.

Frequently it will be found that the duct is not high or wide enough. or has to be otherwise altered because not enough straight section can be found. When an alteration is necessary, care should be taken to allow enough space for the length of the lamp, sockets, and mounting device if any. The minimum length of the transformed duct should be not less than twice the length of the space actually occupied by the lamps, with an equal distance on either side of the lamps. The ends of the altered section should slope into existing ducts gradually, with a 45-degree angle being the maximum that should be used.

The average theatre air-conditioning system can be surveyed in less than an hour. The basic fact to be determined is the number of cubic feet a minute is carried by the system. Usually the owner can provide this information, or it can be secured from the company that installed or that serviced the equipment. Once this figure is known, the number of lamps needed can easily be determined.

Determining the actual number of lamps to be used in any installation has been rendered comparatively simple, through the development by Westinghouse engineers of special charts for different duct systems of various sizes and capacities.

The recommended method of mounting

Sterilamps in the plenum chamber of air-conditioning systems in the use of a rack, with the transformer wiring and transformers (connected to series of more than four Sterilamps) secured to the angle irons at one end of the rack. Since the mounting device is of simple design, adaptation to meet special situations would present no problem. . In the duct type of installation, if the width or height of the radiation chamber varies somewhat from multiples of three feet, the electrode receptacles at the center of the chamber may be allowed to overlap. It is possible in this way to adapt the spacing of the inner electrode receptacles to fit lamps. Where the air ducts are only a few inches less than 3 feet, the lamps may pass thrOugh holes in the wall of the duct, and the electrode receptacles may be supported on brackets outside the duct. If so, a tight cover must be provided over the receptacles to prevent leakage, as the openings in the side walls must be large enough to permit insertion and removal of the lamps.

While a rack suitable for duct installation may be designed, it is more convenient to place the sockets in holes drilled in the duct walls and mount the Sterilamps in this way. A Z- or Ushaped bracket, attached to the walls of the duct to provide the necessary 36-inch spacing for sockets at opposite ends of a 30-inch Sterilamp, has been found useful where the width and depth measure more than 36 inches.

In order to meet new conditions, the

1945 Theatre Catalog, 4th Edition, Page 522