SUGAR-CANE SIRUP MANUFACTURE 85 
rapidly corrodes and destroys galvanized iron. The principal dis- 
advantage of swing-joint connections is that they gradually work 
loose and cause leaks. 
Oil burners under a long open evaporator are also practicable for 
large-scale sirup manufacture. Large plants have a plentiful supply 
of steam with which to atomize the fuel oil; small plants must 
atomize the oil by mechanical means (p. 24). 
MECHANICAL CLARIFICATION 1° 
By C. F. Watton, Jr., Bureau of Chemistry, U. 8. Department of Agriculture 
Both the small-scale manufacture of sirup, by the boiling and skim- 
ming method, and the large-scale manufacture, by the use of sulphur 
dioxide and lime, have disadvantages. The simple boiling and ee 
ming method is compara- 
tively slow and wasteful 
and, unless it 1s very care- 
fully conducted, does not 
completely remove the sus- 
pended particles present in 
the juice. Sirup made by 
his process varies greatly 
in quality, not only because 
the sugar cane varies in 
character but also because 
the equipment used in man- 
ufacture and the skill of 
the sirup maker vary. The , 
chemical process of clarifi- \ 
cation using sulphur dioxide 
and lime is open to the ob- 
jection that many people 
dislike the flavor of the 
resulting sirup. Moreover, 
unless enough of the chem- ( 
ical reagents is added to the CS 
juice, the insoluble material 
separates slowly and incom- 
pletely, whereas an excess 
YLWVC-SONVT_ COPPER COVL 
FOR WAREOY £97 OR (ROUGH 
INLET 
TROUG/S 
of lime makes the sirup SSS S55 
dark and too much sulphur Za I. 
dioxide gives it a peculiar UNION 
metallic flavor. Both the 
small-scale method and the. t i 
: ° O'SECTION OF STEW? 
chemical process of clarifi- 8 222 Fae ZEA ORTIOR, 
cation, however, are widely 
used and have the advan- Fic. 8.—Steam coils with swing-joint connections 
tages already enumerated. 
The so-calied mechanical method of clarification is a comparatively 
recent development, which promises to have useful applications. 
Sugar-cane juice, when heated to boiling for the purpose of coagulat- 
ing certain of its constituents, is usually very difficult to filter because 
the coagulated material, bemg gummy, quickly clogs the pores of 
_10 This section supersedes Department of Agriculture Bulletin 921, ‘‘Sugar-cane juice clarification for 
sirup manufacture,”’ by J. K. Dale and C. S. Hudson, issued November 9, 1920. 
