S P R A Y COOLING PONDS H. E. STIDSTONE Spray Engineering Corn.Danv.Somerville, Mass.
W i t h t h e system surrounded by an efficient well-designed louver fence, this horizontal distance of 25 feet can be reduced to 12.5 feet without s e r i o u s l y a f f e c t i n g the cooling results. T h e typical installation and spray group shown in Figure permits maxiFIGURE3. RAMP-BOTTOM NONCLOGGING NOZZLE mum cooling with a minimum space requirement. The nozzle is the most important part of any spray cooling system. The efficient ramp-bottom nozzle of the nonclogging type (Figure 3) produces a fine uniform spray a t low pressure C O O L I N G R A N I E S ,OK and is carefully designed to spray to the proper height necesFIGURE1. ACTUALCOOLINCTO BE EXPECTED FROM A sary for effective cooling without excessive drift. This nonSPRAYPOND clogging nozzle has a large free passageway the hotter months of the year most of which will permit spraythe cooling is done by evaporation; in ing liquids which conthe cold weather most of the heat is tain foreign matter that transferred to the air by conduction would clog the ordinary and radiation. nozzle. The temperatures of the water enI n selecting the site tering a spray system are reduced a for a spray cooling pond, fixed amount, depending upon the atcare should be taken not mospheric conditions-that is, the air t o choose a location dry-bulb temperature and the air wetwhere obstructions such bulb temperature. Figure 1 shows as buildings or high the actual cooling which could be points of land would reexpected from a spray pond, operatstrict the proper air ciring at a recommended pressure of 7 culation around the pounds per square inch at the nozzles sprays. with an average wind velocity of 5 T h e approximate miles per hour, based on actual tests present-day cost of the over a period of more than 20 years. equipment over a pond Constant rechecking has proved the say, of 5000 gallons per chart to be accurate. Actual records minute capacity, exclushow t h a t the average amount of sive of the pond itself, make-up water required does not exfigures roughly 35 cents ceed 2 per cent of the water sprayed. p e r g a l l o n of w a t e r NO N R SPRACO NOZZlES The cooling shown in Figure 1 is sprayed, based on 200based on the general practice used in gallon-per-minute spray pond design-namely, a group groups operating a t the of four nozzles each carrying 200 galrecommended pressure Jf'T,ON An lons per minute, placed on 13-foot of 7 pounds per square centers along the supply lines and 25 inch a t the nozzles. feet between the rows of spray groups. To illustrate how the The tips of the nozzles are placed 5 feet capacity of a spray coolabove the water level in the spray ing pond is derived when pond, spraying vertically upward, used in connection with There should be a horizontal distance a steam turbine, let us of 25 feet between the center of the assume that the turbine FIGTJRE 2. TYPICAL INSTALLATION AND SPRAY GROUP nearest ripray group and the inside is designed for best effiNozzles with straight arms, !pray head, and standard spray of the pond wall when the system is ciency a t a 28-inch vactee with blank flange and drip spray are shown . The plate not surrounded by a louver fence. and roll mounting accommodate expansion of the pipe line. uum and installed where 991 ARIOUS methods and formulas have been advanced which enable the engineer to compute the theoretical cooling obtainable by atmospheric spray cooling ponds. The cooling of water by spraying it into the atmosphere is effected by evaporation, conduction, and radiation. During
992
INDUSTRIAL AND ENGINEERING CHEMISTRY
the atmospheric conditions during the summer months average 80" F. dry bulb and 60 per cent relative humidity. At 28-inch vacuum the temperature of the circulating water leaving the condenser, based on a 5" terminal difference bet w e e n t h e condensate and the circulating water, would be 96.2" F. Figure 1 shows that the temperature of 96.2" F. intersects the 80-60 curve a t the 15"F. cooling range. Therefore with the turbine operating a t a 28-inch vacuum, the water sprayed through the cooling pond equipment will be cooled through a range of 15" F. when the surrounding air drybulb temperature is 80" F. with a relative humidity of 60 per cent. Assuming that 960 B. t. u. per pound of steam condensed are absorbed by the condensing water, knowing that the water would be cooled through a 15"range, and dividing 960 B. t. u. by 15" F. cooling range, it is found that 64 pounds of water should be circulated for each pound of steam condensed. In other words, the amount of water sprayed through the cooling pond should be sixty-four times greater than the amount of steam condensed or a ratio of water to steam of 64 to 1. If only 26-inch vacuum is required, the ratio of water to steam can be reduced, thereby reducing the capacity of the spray pond. Roof spray cooling systems used in connection with ice and refrigeration plants have proved very efficient and economical to operate. Based on more than 20 years of experience and a large amount of test data taken during that period, it has been determined that 5 gallons per ton of refrigeration capacity (not ice-making capacity) will give approximately a 6' F. rise in the temperature of the circulating water, and that it can be
VOL. 30, NO. 9
cooled very close to the surrounding air wet-bulb temperature, the air wet-bulb temperature being the absolute limit of atmospheric water cooling. Where installations are made on
FIGURE 4. SPRAY PONDON THE ROOFOF AN ICE PLANTWHICHPAIDFOR ITSELFIN LESS THAN 18 MONTHS Sprays 1800 gallons per minute
the roof of a building, such as shown in Figure 4, the system should be surrounded by a louver fence. The patented metal type of louver fence shown has proved efficient and effectively prevents wind drift, which is essential with this type of installation. The general practice in spray pond design is to make the nozzles of bronze, the spray arms of galvanized steel, and the supply piping and fittings of cast iron. RBCEIVED December 18, 1937.
THE ALCHEMIST By David Teniers, the Younger
A list of Reproductions Nos. 1 t o 60 appeared in our issue of January 1936, page 129; the list of Nos. 61 to 72'appeared in January, 1937, page 74: Nos. 73 to 84 are listed in Januarv. 1938. Daee 70. where also is shown No. 8-5 and dkt& for obtaining photographic copies of the originals. No. 86 appears on page 145, February issue; No. 87, page 269, March issue: No. 88, page 427, April issue; No. 89, page 500, May issue: No. 90, page 631, June issue; No. 91, page, 834, July issue; No. 92, page 933, August issue. The photographs of these paintings are supplied in black and white only.
Through the very kind cooperation of Mr. Chester G . Fisher, we are able to reproduce as No. 93 in the Berolzheimer series of Alchemical and Historical Reproductions the fourteenth painting by those prolific Dutch painters, David Teniers, Father and Son. The original painting was privately owned in England for many years until it was acquired by s i r A. s. Hunter in 1852. Last year while in England, M ~Fisher . purchased it from a private home a t Mortimer ill, Berkshire, and brought it to the United States, where it hangs in his office in Pittsburgh as a part of his extensive collection of prints and pictures. The original is signed in the lower right-hand corner, where also will be found the date "1648."
This painting greatly resembles one of the previous Teniers' reproductions, No. 2 in the series- These two Paintings have more frequently been the subjects of engravings, in Part by worldfamous engravers, than all the other Teniers' paintings. Only recently the Eaton-Clark Company of Detroit issued a very handsome bronze medal in commemoration of their Hundredth Anniversary. With Mr. Fisher's permission the obverse of the medal depicts a part of this Teniers' painting most excellently executed. D. D. Berolzheimer 50 East 41st Street New York. N. Y.
