TURPENTINE. | 19 
The minimum thickness of metal from which tanks of various sizes 
for general transportation purposes are constructed, according to 
specifications adopted by the Master Car Builders Association, is 
shown in Table 2. : 
* TaBLE 2.— Minimum thickness of metal for constructing tanks. 
* “ 3 
Pea eto zoo Shellsheet. | Tank heads.| Dome. 
Inches. Inches. Inches. Inches. Inches. 
60 or less ws 4 4 | Hs 
60to78 : — a 4 5 
78 to 96 4 Zz ik S 
To calculate exactly the total loaded capacity of a tank car it is 
necessary to determine the volume of the straight or cylindrical 
length of the tank, and also that of the two dished ends. To the sum 
_ of these is added the volume of the 
’ so-called ‘‘dome pockets” (fig. 2), 
that is, the space taken up by 
liquid in the round dome when the 
tank is entirely full to the apex of 
the shell. 
The dished ends of the tank are 
segments of alarge sphere. Pres- /~ Dgme/dchers 
ent practice in tank-car construc- 
tion is to bend the dished ends on 
a radius of 10 feet for all sizes of 
tanks. When the tank end is bent, 
a short cylindrical portion always 
> extends out from the spherical 
» part, through which it is riveted to 
the body of the tank. 
A portionof this short cylindrical 
part of the tank head usually ex- 
tends out from the butt of the end sheet of the shell, a distance of 
about 1 inch, and is known as the ‘‘regular extension.’’ The inside 
length of the regular extension is approximately {inch less than the 
outside measurement from the butt of the end sheet of the cylinder 
to the point where the curve of the head starts. The total depth of 
the dish or hilge is equal to the sum of the regular extension plus the 
+. bilge proper, and, since the head fits inside the tank and the thick- 
“ness of metal for tank heads of all sizes is one-half inch, the inside 
diameter of the tank head is 1 inch less than the inside diameter of 
the endsheet. The latter is determined, as before, by multiplying the 
outside circumference, in inches, by 0.31831 and subtracting the sum 
of the thickness of metal used for the shell and bottom sheets. 
Fic. 2. 
