24 BULLETIN 1158, U. S. DEPARTMENT OF AGRICULTURE. 
Hopper Scales. 
A standard-type beam scale, with a sheet-iron hopper suspended, 
is used for weighing the potatoes as they come from the potato 
washer. The hopper is 5 feet long by 3 feet wide by 2 feet deep, 
which is large enough to weigh 20 bushels, or 1,000 pounds, of pota- 
toes at a time. It is mounted on a pivot. 
Elevator. 
From the hopper scales the sweet potatoes are dumped into a chute 
which discharges them into the boot of a standard-type incline ele- 
vator, equipped with a few variations to meet the needs in this par- 
ticular case. The belt, which is 3 feet wide, is equipped with metal 
buckets that form a sort of pocket in which the potatoes rest and are 
carried to the top of the mash tank. Here the potatoes are dis- 
charged into a chute which dumps them into the mash tank. The 
elevator is 16 feet between pulley centers. The driving pulley makes 
20 revolutions per minute, giving with 20-inch head pulley a belt 
speed of 104 feet a minute. 
Measuring Tank. 
After the sweet potatoes have been steam blanched water of the 
same weight as the potatoes must be added before the mashing oper- 
ation is started. To facilitate the measuring and handling of the 
water, an elevated measuring tank is used. The tank is made of 
24-gauge galvanized iron and is 4 feet in diameter and 6 feet deep, 
with a capacity of approximately 4,600 pounds, or 550 gallons, of 
water. A lj-incji outlet quickly discharges the water from the meas- 
uring tank into the mash tank. The tank can be readily filled by 
means of a water pipe extending over the top of the tank. The num- 
ber of pounds of water in the tank at any time may be determined by 
a float arrangement attached to an indicator which runs on a cali- 
brated scale. The tank is mounted on a platform high enough to 
permit the water to be discharged into the mash tank by gravity. 
Cooling Tanks. 
In order to allow the crude sweet-potato sirup to stand for 
approximately 40 hours and at the same time keep each batch sepa- 
rate, two cooling tanks are required. These tanks are copper- jack- 
eted kettles. 3 feet 2 inches in maximum diameter and 5 feet deep, 
with a capacity of 225 gallons each. The jackets of the tanks are 
equipped with steam and water connections for heating or cooling 
as desired. The sirup can be drawn from the tanks through a 
1^-inch outlet. 
In order to keep the kieselguhr in suspension during nitration the 
tanks are equipped with mechanical agitators, which really are 
propellers mounted at the end of H-inch shafts. Each contains three 
8-inch blades and is driven by means of beveled gears and pinions. 
The ratio of the pinions to the gears is 1 to 3. The pinions are driven 
at 90 revolutions per minute, giving the propellers a speed of 30 revo- 
lutions per minute. The kettles or tanks are mounted on steel stands. 
