290 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1958 
is passed through a series of evaporators under reduced pressure and 
temperature, utilizing either heat applied directly from a steam gen- 
erator or that recovered from the exhaust of a steam turbine in con- 
nection with electric power generators [13]. (Fig. 3.) The efficiency 
and economy of the process require completely scale-free operation 
which we believe can be achieved through pH control and/or internal 
sludge-stabilization techniques. In addition, Badger proposed the 
use of low-cost (ferrous) metals throughout the plant. In order to 
bring these theories into practice, a pilot plant has been erected at a 
seashore location in North Carolina for testing scale prevention, metals 
corrosion, heat transfer rates, and other variables for the long-tube 
vertical-evaporator distillation process (pl. 1, fig. 1). Badger esti- 
mates the total cost of water from a large plant at about 40 cents per 
thousand gallons. 
FLOW SHEET OF SEA WATER DISTILLATION PLANT 
Fic. 3.—Flow sheet of multistage, long-tube vertical distillation plant. (Layout is after 
cycle of W. L. Badger.) 
Improved evaporators in which greatly increased rates of heat trans- 
fer are achieved give promise of reducing capital as well as operating 
costs. In one such development [14], the heat transfer coefficient is 
increased to 2,000-8,500 B.t.u. per hour per square foot per °F., as 
compared to 500 or less in conventional equipment. In this process, 
invented by Dr. Kenneth C. D. Hickman of Rochester, N.Y., the heat- 
transfer area is in the shape of conical surfaces and is rotated, thereby 
causing the feed water to spread over the surface in thin films, under 
centrifugal force. Several experimental models have been built, from 
household sizes (800 g.p.d.) to much larger plants (25,000 g.p.d.) 
(pl. 1, fig. 1), and are being tested on brackish water as well as sea 
water. 
Another heat-transfer system is under development by Drs. B. F. 
Dodge and A. M. Eshaya of Yale University, New Haven, Conn. 
Tests were run on laboratory equipment at the University [16] which 
demonstrated that heat transfer coeflicients of 2,000 B.t.u. per hour per 
