26 BULLETIN 898, U. S. DEPARTMENT OF AGRICULTURE. 
The dome pockets (Table 3) for a dome 44 inches in diameter on 
a 78-inch diameter tank hold, when full, 10 gallons. In order to deter- 
mine whether these pockets will be entirely empty at any particular 
outage, compare the length of the 
chord C (Ime bc), as calculated on 
page 23, with the diameter of the 
dome. If the value of this chord 
is equal to or greater than the 
diameter of the dome, the pockets 
willbe empty. If Cis less than the 
diameter of the dome, there will be 
some liquid in the pockets. In the 
present case C is equal to 41.6 
inches and the dome diameter to 
44 inches, so that there will be some 
liquid in the pockets. | 
The quantity of liquid in the 
dome pockets at any particular 
outage can be determined approx- 
imately in the following manner: 
First determine the maximum 
depth of the dome pockets, i. e., the outage at which they will be 
just empty, represented by the line de in figure 5. In the right- 
angle triangle aec, ac? =ae? + ec”, or a =a — ec. 
Then, 
Fia. 5. 
ae = Jae — ee. 
Since ac and ec are known, being, respectively, the radii of the 
tank and dome, ae can be determined. The difference bétween the 
radius of the tank and ae represents the length of the line de, which 
is the maximum depth of the dome pockets. Table 4 shows the pro- 
portion of the total dome pocket capacity, as given in Table 3, page 
20, which is empty for any particular ratio between the measured 
outage and the maximum depth of the dome pocket. 
TABLE 4.—Proportion of total dome capacity empty for various ratios. 
Ratio of 
outage . 
mee Proportion of 
total dome 
BR pocket capacity 
Be that is empty. 
dome 
pocket. 
Ye cease 0 
1 2 
Dore teee-- 2 
3 2 
Brss2e+22- 3 
i 3 
2Z-++e----- 4 
5 7 
= eee ete eee e 
Goce er eee . Yo 
Loseete eas Practically 
entirely 
empty. 
