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1950-51 Theatre Catalog, 9th Edition, Page 370 (348)

1950-51 Theatre Catalog, 9th Edition
1950-51 Theatre Catalog
1950-51 Theatre Catalog, 9th Edition, Page 370
Page 370

1950-51 Theatre Catalog, 9th Edition, Page 370

FIGURE 3-5 commonly used type of blower. (Photograph courtesy of U. S. Air Conditioning Corp.)

Areas with 770 to 780 designed Wet-Bulbe90 c.f.m. per seat Areas with 780 to 800 designed Wet-BulbeIOO c.f.m. per seat The above table is for high temperature areas. In those areas where the normal dry-bulb temperature is 940 or less a 5 to 10% reduction in c.f.m. is justified.


The actual heat exchange or evaporation takes place in an air washer, where a spray or fog of water is placed in intimate contact with the air passing through the chamber. Such an air washer is illustrated in Fig. 4. Another style of air washer is indicated in Fig. 5, where the water contact is not made through spray action but by passing the air through a saturated mat of fibres, which in themselves present a very large evaporating surface to the air passing through the unit. The fibres themselves are made of many diEerent materials, including aspenwood, woven glass thread, and other materials.


One cardinal advantage of an evaporative cooling system is that it requires little maintenance. Once the equipment

FIGURE 4-An air washer with spray action. (Photograph courlesy of U. S. Air Conditioning Corp.)

has been installed, about all that is necessary is to clean the washer out approximately once a month and refill with fresh water. If ball bearings are used in the blower and motors, one greasing per season should prove satisfactory, while sleeve bearings, if any, should be oiled about every 30 days. After the end of the season, the complete system should be thoroughly cleaned, repainted, and closed up as much as possible for protection against the winter weather.

When the system is put back to operation in the spring, the pads should be checked to see whether repacking is necessary. The tank is then filled with water, and all bearings are greased or oiled. Finally, the pump should be started and an inspection made to determine whether all spray nozzles are working satisfactorily. .


In spite of the fact that a good number of theatres have been equipped with evaporative cooling, many theatre opera

FIGURE S-An air washer with mat of fibres. (Photograph courtesy of U. 5. Air Conditioning Corp.)

tors, architects, and builders know little about the important details to be considered in making an installation which will do the job in an expert fashion.

Typical Roof Installations

Fig. 6 shows both top and side views of a typical roof installation. While theatres are often equipped with two separate evaporative cooling systems, this illustration may well be of interest to theatre operators contemplating a new evaporative cooling installation where only one large unit is necessary. By using two separately regulated pumps on the air washer a very satisfactory humidity control is possible during high humidity periods.

Another example of a roof installation may be seen in Fig. 7, where the cooling element (screen rotor) continuously exposes an evenly wetted surface to the air how, maintaining a constant cooling effect. The water that is exposed to the air is in the form of a film held on a golden bronze screen. The screen is corrugated at an angle, and the corrugations, acting as troughs, drain the exoess water into the unconditioned air side of the tray as the rotor revolves; thus, the

possibility of moisture entrainment and the resulting deposit of raw water in the space to be cooled is eliminated.

Supply Grilles

Fig. 8 illustrates the customary type of supply grille used in the theatre to control the air stream passing through the auditorium. It is customary to place such supply grilles on the proscenium arch so as to allow a straight projection of air from front to back, allowing exhaust through the doors of the auditorium or through gravity vents in the ceiling at the rear end. It can thus be seen that a horizontal flow of air is obtained.

The adjustable blades of the grille allow control of the placement of this air so as to achieve uniform coverage. Perceptible air motion in the case of the evaporative cooling system is greatly desired and is not felt as a draft or uncomfortable air movement because the temperature has not been reduced greatly and all patrons are facing the source of air motion.

Controlling Grilles

The usual method for installation of an evaporative cooling system places the equipment up at the stage end of the house. Located on the stage proper, in the basement below, in the iiy-loft above, on the roof, or in the rear, all such installations invariably lead their supply air to two or more controlling grilles located so as to project the air toward the rear of the house. Fig. 9 illustrates a typical installation, of which numerous varieties can be found, in the Beverly Hills Theatre, Dallas. Two 25ton evaporative cooling units have been installed here.

Other Suggestions

According to some authorities on evaporative cooling, it is oftentimes advisable to have two double deflection grilles, located on each side of the proscenium arch and seven or eight feet above the door, to effect better control of the air. It is claimed that a separate grille setting is frequently required for the front half of the auditorium and a

FIGURE G-Top and side views of root installation where only one large unit is really needed.

1950-51 Theatre Catalog, 9th Edition, Page 370