Motion Picture Herald (May-Jun 1946)

on paper, thus permitting the development of a "lo^' for guidance in determining load requirements and other operating factors. The other is an "Effective Temperature" thermometer (marketed under the trade name of "Therhumiter"), which ingeniously combines response to the temperature of the air, moisture in the air, and the motion of the air so as to give a direct reading of their relative and aggregate effect upon the comfort conditions of the air, which reading is that of "Effective Temperature"— that is, the true temperature from the point of view of comfort It thus eliminates the calculation necessary with dry-bulb and wetbulb thermometers to determine what the Effective Temperature is, and it also provides a simple means of determining the percentage of relative humidity. [The functions of air-conditioning and air distribution equipment and systems, their critical factors and operating considerations, etc., form too broad a subject for comprehensive discussion here; they have been, and are being, constantly dealt with in special and departmental articles in Better Theatres.] SIMPLE VENTILATION Simple ventilation of theatres requires blower equipment of suitable capacity to draw in the fresh air and propel it through ventilators (normally located adjacent to the proscenium arch or screen opening), plus any direct draft exhaust fans and duct contacts with the outside (as from toilet rooms) that the structural plan of the building may require. The blower equipment of course is of importance; it should be of a capacity to ensure the required supply of fresh air, be durably built, and be quiet in operation. A simple ventilation system may provide air cooling for an auditorium by passing the outside air through a cold-water spray diamber (air washer evaporative cooling). This also cleanses the air. AIR WASHERS American Blower Corporation, 6004 Russell Street, Detroit, Mich. The Ballantyne Company, 1707-11 Davenport Street, Omaha, Nebr. United States Air Conditioning Corporation, Northwestern Terminal, Minneapolis, Minn. BLOWERS AND FANS American Blower Corporation, 6004 Russell Street, Detroit, Mich. The Ballantyne Company, 1707-11 Davenport Street, Omaha, Nebr. Clarage Fan Company, Kalamazoo, Mich. Garden City Fan Co., McCormick Bldg., Chicago, 111. llg Electric Ventilating Company, 2850 N. Crawford Avenue, Chicago, 111. Reynolds Manufacturing Company, 412 Prospect Avenue, N. E., Grand Rapids, Mich. B. F. Sturtevant Co. (Division of Westinghouse) , Hyde Park, Boston, Mass. United States Air Conditioning Corporation, Northwestern Terminal, Minneapolis, Minn. COJLS McQuay, Inc., 1600 Broadway, N.E., Minneapolis, Minn. CONTROL EQUIPMENT The Brown Instrument Company, Philadelphia, Pa. Minneapolis Honeywell Regulator Company, 2822 Fourth Avenue, S., Minneapolis, Minn. Monitor Controller Company, SI S. Gay Street, Baltimore, Md. FILTERS American Air Filter Company, 125 Central Avenue, Louisville 8, Ky. Coppus Engineering Corporation, Worcester, Mass. Owens-Coming Fiberglass Corporation, Ohio Building, Toledo, Ohio. Research Products Corporation, 1015 East Washington Street, Madison 3, Wis. Universal Air Filter Company, Duluth, Minn. GRILLES AND DIFFUSERS Air Devices, Inc., 17 E. 42nd Street, New York City. American Blower Corporation, 6004 Russell Street, Detroit, Mich. Anemostat Corp. of America, 10 E. 39th Street, New York City. Barber-Colman Company, Rockford, 111. New York Brass & Wire Works Company, 434 Broadway, New York 13, N. Y. Tuttle & Bailey, New Britain, Conn. 34 REFRIGERATION MACHINES Airtemps Division, Chrysler Corporation, 1113 Leo Street, Dayton 1, Ohio. American Blower Corporation, 6004 Russell Street, Detroit, Mich. Baker Ice Machine Company, 3601 N, 16th Street, Omaha, Nebr. Carrier Corporation, Sjrracuse, N. Y. Frigidaire Division, General Motors Sales Corporation, 300 Taylor Street, Dayton, Ohio. General Electric Company, 5 Lawrence Street, Bloomfield, N. J. General Refrigeration Corporation, Shirland Avenue, Beloit, Wis. United States Air Conditioning Corporation, Northwestern Terminal, Minneapolis, Minn. Westinghouse Air Conditioning and Industrial Refrigeration Div., Westinghouse Electric Corporation, 150 Pacific Avenue, Jersey City 7, N. J. Worthington Pump and Machinery Corporation, 744 Broad Street, Newark, N. J. York Corporation, York, Pa. TEMPERATURE READING DEVICES The Brown Instrument Company, Philadelphia, Pa. Minneapolis Honeywell Regulator Company, 2822 Fourth Avenue, S., Minneapolis, Minn. • AIR PURIFICATION: ELECTRIC AND CHEMICAL THE MOST effective method of removing dust and bacteria from outside air upon its introduction into the theatre ventilating system is by electrostatic precipitation. This is effected by special equipment consisting, essentially, in an electrical power pact and collector cells of the specific capacity required by the amount of air hsmdled. This method also is highly efficient for the removal of bacteria and irritating substances, and accordingly is relatively expensive. For removal or at least reduction of impurities in air that cause odors, a chemical method is available, involving the action of synthetic chlorophyll, the substance of green plants. For application to ventilating duct systems, a forcedevaporation unit is connected through a bypass. Units are also obtainable for placement in rooms. B. F. Sturtevant Company (Division of Westinghouse), Hyde Park, Boston. Mass. (Electric). W. H. Wheeler, Inc., 7 E. 47th Street, New York City. (Chemical). • AMPLIFYING TUBES THESE ARE electronic relays in the amplifier of a sound reproducing system by means of which the weak electric currents created by a photocell, phono-pickup or microphone, are made strong enough (while maintaining the original current pattern) to operate the loudspeakers. (See Amplifiers.) General Electric Company, 1. River Road, Schenectady, N. Y. National Union Radio Corporation, 57 State Street, Newark, N. J. RCA Victor Division of Radio Corporation of America, Camden, N. J. Raytheon Manufacturing Company, Foundry Avenue, Waltham, Mass. Westinghouse Electric Corporation, Bloomfield, N. J. AMPLIFIERS AN AMPLIFIER, as part of a soimd reproducing system, is the arrangement in an electrical unit (panel or cabinet) of electronic relays (see Amplifying Tubes) with suitable controls. Amplifiers today contain their own power supplies, needing only connection with an a.c. or d.c. power line, and dispensing with all auxiliary batteries, generators or rectifiers ; and in addition commonly supply polarizing voltage to photocells, and sometimes current to exciter lamps and loudspeaker fields. Modem preamplifiers and monitor amplifiers commonly draw this operating power from some other amplifying unit of the sound system. Very small, low-power amplifiers may be mounted on the projector or on the wall of the projection room, deriving their operating power from the main amplifier. They provide preliminary amplification of the weak photocell current before it reaches the main amplifier. Amplifi^ arrangements in a small theatre may consist in a single, compact, combination amplifying and power supply unit mounted on the projection room front wall, between projection ports; or alternatively, of such a comDination unit plus a small pre-amplifier which receives the initial current from the photo-cell. In larger systems, a number of amplifying network and power supply units are mounted on a steel rack or frame, or in a steel cabinet, which is located at the rear or one end of the projection room, or occasionair_ ■ built into the wall dividing the projection room from another TOonP of the projection suite. Medium and large-size systems today include a separate monitor amplifier-speaker cabinet, often suspended from the projection room ceiling by steel straps. The monitor amplifier is sometimes self-powered; sometimes, like the photo-cell amplifier, derives its operating current from the larger system amplifier. Volume control and sound changeover equipment is today commonly associated with the irfioto-cell pre-amplifier. Modem amplifiers or amplifying racks are often equipped with decibel meters for accurate measurement of sound output and quick servicing. Emergency amplifiers may be exact duplicates of the normal amplifying system, or smaller, less elaborate apparatus, and in some systems the monitor amplifier is utilized to sup ply sound to the audience in an emergency. Altec-Lansing Corporation, 1161 North Vine Street, HolKrwood, Calif. Amplifier Company of America, 398 Broadway, New York 13, N. Y. The Ballantyne Company, 1707-11 Davenport Street, Omaha, Nebr. DeVry Corporation, 1111 Armitage Avenue, Chicago, International Projector Corporation, 88-96 Gold Street, New York City. Earle W. Meredith, 182 Avondale Road, Rochester, N. Y. Motiograph, 4431 West Lake Street, Chicago, lU. American Air Filter Company, Inc., First & Central Avenues, Louisville, Ky. (Electrical). RCA Victor Division of Radio Corporation of America, Camden, N. J. S. O. S. Cinema Supply Corp., 449 West 42nd Street, New York City. Weber Machine Corporation, 59 Rutter Street, Rochester, N. Y. Western Electric Company, 195 Broadway, New York City. ANCHORS FOR CHAIRS EXPANSION BOLTS suited to andioring chairs in concrete flooring are available with metal jacket. A leading make of metal anchor consists of an especially long tapered fin head bolt, conical cup, lead sleeve, washer and hexagon nut. Chicago Expansion Bolt Company, 2240 West Ogden Avenue, Chicago, 111. Fensin Seating Company, 62 East 13th Street, Chicago. 111. Joe Hornstein, Inc., 630 Ninth Avenue, New York, N. Y. • ARCHITECTURAL MATERIALS AND DESIGN SERVICE PROGRESS IN chemistry and in manufacturing technique have made available a wide variety of decorative materials to supplement or supplant the familiar marble, stone, brick, ceramic tiles, plaster, etc. Architectural glass can be had in both facing tiles and structural blocks. The tiles offer a complete selection of colors and a number of pattems (some of them simulating marble). Glass blocks are also available in colors and pattems ; they are not only adapted to the construction of architectural features like towers and window effects (admitting light, but assuring privacy), but also to interior partitions. TransltKent glass blocks lend themselves to interesting luminous treatments. Mirrors, in large panel effects (sectional or otherwise) as well as in smaller sizes of various shapes, are effective decorative elements while at the same time contributing a sense of spa BEHER THEATRES. MAY 4. 1946