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1948-49 Theatre Catalog, 7th Edition, Page 409 (396)

1948-49 Theatre Catalog, 7th Edition
1948-49 Theatre Catalog
1948-49 Theatre Catalog, 7th Edition, Page 409
Page 409

1948-49 Theatre Catalog, 7th Edition, Page 409

FIG. 7-Feed motor and associated mechanism including ventilation blower.

and the spring housing at its outer end. By this means an effortless featherweight feed of the negative carbon holder is accomplished.

"Hy-Speed" f/2 Condenser Lens

The Peerless ttHy-Speedli f/2 condenser-lens system is ground exclusively for us by Bausch and Lomb Optical Company of Rochester, New York. The rear lens is obtainable, made of either fused quartz or of Pyrex glass. It is 614 inches in diameter. The fused-quartz lens is furnished with a 3/3-inch edge on the rear surface to permit quite a number of resurfacing operations when it becomes badly pitted from exposure to

the burning arc. The front lens is made of Corex Glass and is 7% inches in diameter.

The operating distance between the arc crater and the rear surface of the rear lens is 3 inches and the working distance between the foremost point of the front curve of the front lens and the film line is 121%6 inches. These operating distances provide 80 degrees sideto-center screen-light distribution.

Light-Heqi-Fil'l'er UnH'

Because of the high order of light and light heat encountered when 160 to 180 amperes is drawn at the arc in combination with our "Hy-Speed'i f/2 con FIG. B-Lelt side of lamp showing lump mechanism.

denser-lens system, to prevent film damage, some years ago we developed and made available to theatres using these high currents, an air-cooled, glass heatfilter unit. (Fig. 9).

The main frame of-this heat filter attaches to the rear face of the rear shutter housing of the projector mechanism and provides the enclosure into which fits the frame for the filter glasses. The glass frame is supported by ears at its top with ample room between all sides of it and the main frame inner walls, to permit free passage of the air blown into this compartment from a centrifugal electric blower.

There are eight filter-glass strips used, each strip is approximately 1/2 of an inch wide. They mount in their holder vertically and in a staggered relationship to each other. Hence the air stream from the blower may pass completely over all surfaces as well as the edges of each strip of filter glass and, in consequence, efiiciently radiate the heat each glass strip absorbs from the light.

Convenient means are provided to attach the motor-blower assembly to the projector pedestal. We recommend that the blower motor should be connected to the open end of the arc-lamp switch to ensure its operation simultaneously with the energization of the arc-lamp circuit when the arc switch is closed to strike the arc.

In operation the air is conducted from the blower to the hollow compartment of the filter main frame by a flexible plastic tubing of ample diameter. The air directed into the glass frame compartment mounted on the mechanism rear-shutter housing, passes over and all around each individual filter-glass strip and exhausts upward, out of the vent at the top of the main frame into the projection room.

Corning Glass Alko No. 8966 filter glass is employed and has proved to be very satisfactory in performance.

NOTE: The foregoing described equipment has already been installed and is in use by Radio City Music Hall, Roxy Theatre, Balaban and Katz Chicago Theatre, and hundreds of the foremost theatres as well as drive-in theatres in the United States and abroad.

Wafer-Cooled Positive Contacts

To aid in the Work being conducted by the National Carbon Company at Fostoria, Ohio, on the 290-ampere, 13.6mm experimental projection arc carbon trim and also the. Eastman Kodak Company at Rochester, N. Y., Who are concerned with the high light temperatures that film will be subjected to through the use of these currents in theatre projection, we developed and furnished each of these companies a modified Peerless Hy-Candescent lamp that was equipped with water-cooled positive contact units and certain burner mechanism changes to accommodate the higher consumption rate of these carbons.

1948-49 Theatre Catalog, 7th Edition, Page 409