Ca a 
LEA aS. 
. 
dow, 
—— 
\ 
TEMPERATURE CHANGES, ETC., DURING CANNING OPERATIONS. 15 
Of less importance also is the influence of the linear expansion of 
the metal of the can, due to the rise in temperature. 
Another fact of much importance in connection with all pressure 
and vacuum tests is that individual cans vary considerably in their 
resistance to pressure, whether internal or external. This fact 
accounts in part for some of the irregularities in the experimental 
data presented. 
Expansion of water—The expansion of the water due to the rise 
in temperature likewise has some effect upon the pressure developed. 
This, while unimportant where the quantity of water is small, may 
have a considerable influence where the head space is reduced to a 
minimum, as decreasing the volume of gas in the head space by one- 
half through expansion of the water after sealing theoretically 
doubles the pressure developed by the expansion of the inclosed air. 
In Table 1 no corrections have been made for this expansion. The 
tendency, however, is always to increase the variations between the 
experimental and the theoretical figures. 
Table 3, which has been taken from the work of standard authori- 
ties (see Smithsonian Physical Tables, Fowle, 7th revised edition, 
1920, p. 120; also Kent’s Mech. Eng. Pocketbook, 9th edition, 1916, 
p. 716), shows the increase in volume of a unit quantity of water 
when passing through the range of temperature with which the pres- 
ent work is concerned. 
Taste 3.—Volume of water at different temperatures. 
[The mass of 1 cubic centimeter at 4° C. is taken as unity.] 
Temperature (°C.).| Volume. || Temperature(°C.).| Volume. || Temperature (°C.). Volume. 
hd oa Ope ee? STUDS am el Oe ae ra PEGOTOON Res cos sl ae 1. 03237 
ig 2S A aoe ARR 45 ne te cece cues HEGUORS OO nt sc eee 1. 03590 
OE Ree SoM kT A a TUTTE RG EGE eee Re iat Ae AB OLZOT EOS bace ee ee 1. 03955 
10. ci Se 2 th AE DOO ZTE WS ao os SS on Sako A OL44 8" bl phOOzss lias oe se. 1. 04343 
Siem ys ey ae AE QOOST. 16020. So. esos. ck ote F-01705 | 1108.) ee 1.0515 
Ap wai ae ASOOE TONGS eee etok gt OE 1, 01979) 5.5 Oe See 1. 0560 
725 12 i ie aan ia Pe ODRE SALON. etn <2 enor ce PO2Z70|| 121.1 st eee 1. 0661 
Scag jah ee eae To, Ses | a cr 1. 02576 
iin Ri the sa. GOTT ESOS cs ee 1. 02899 
Table 4, which is based upon the foregoing, shows the actual in- 
crease in volume of water in No. 2 and No. 3 tin cans when sealed 
at various temperatures and processed at 100°, 110° 115.5°, and 121.1° 
C., the initial velume of the water in the No. 2 can being taken as 
550 c. c. and in the No.3 as 950 c.c. The figures are self-explanatory. 
