INDUSTRIAL A N D ENGINEERlh'G CHEMISTRY
:300
The capacity of each reservoir on the electric boiler is calculated on the basis of storing sufficient steam and heat to expel sll the air from the retort, bring the charge to a sterilizing temperature, and carry it through the period of sterilization without the addition of make-up water. The time necessary to expel the air depends upon the nature and size of the charge, which must be heated to the boiling point of water before condensation stops. After this point is reached, the steam can gradually expel the air through suitable vents. These vents should not be closed until a clear Row of steam is established. The energy consumption necessary to maintain a sterilizing temperature is very low, as is evident by the data in Table 111. Table IlI-Eoer@
8%
PnTlnda
-
nlliira
H. l'hninas N-, 1687: charge, 18 gal. 1 1 0 eighteen l ~ g a l giilrs . ?a,; ics,"eialurr. 21" A.
c.-
An Inexpensive Crystal or Molasses Separator' R. H. King Uarviixsirv os
T H E PBILIPPINBS, E r r e n l u z ~ Srn'rro~ ~ 071.
L ~ o i i a n .P. I
tiur-hrr.
Mi*.
30
and cooling a large volume of water means time lost. Not only is the delay hothersome to the manipulator, but i t may also be a menace to tlie proper chemical constituents of the charge, especially to certain sugars in media, some of which are very high priced. The exposure to heat while a sterilizing pressure is being built up in a gas-heated generator is lengthened by the process of cooling down after sterilization has been completed. The cooling process is proportionally delayed by the amount of heat still in tlie generator, under pressure. after the gas bas been turned off. The most satisfactory method is that which gives a sterilizing temperature immediately and allows one to stop the supply of heat as soon as the charge has been sterilized.
Consumption for Vsrlovs Sferillrlne Time3 nf L A K C S Silil"
15 20 2.5
Vol. 23, No. 3
0.85 1 ~ 5
1.6
3 0 0 0
.. 7 . 0 ...
A set of tests was conducted in which the temperature in tho retort w&s chocked each minute with the pressure. In Table I V it will be noticed how quickly a sterilizing temperatitre was reached. Also it will be noted how little lag there was in tlie thermometer as the rxessure was increased or allowed to drop. The vents were not closed until 100' C . had been attained. 'This temperature is more quickly reached by using 0.5 pound pressure in clearing the retort of air. On this aotoclave it took 12 minutes at 0.5 pound pressure to clear of air and 17 minutes at 0 pounds pressure using tlie same charge of 4 gallons of water at 21" C . Discussion
For sterilizing purposes aiid other processes where steam and heat are required, the use of the electric steam generator as described in this paper is a forward step in economy. It is not now necessary to maintain the yearly expense of providing steam in higli-pressure mains. Ttiis electric highpressure steam boiler will give all that can be desired from a high-pressure main, not only in the service performed, but also in manipulation and constancy of temperature, and with a fraction of the cost in producing lieat. The use of fuel or electric steam generators that build up a sterilizing temperature in a retort decreases the working efficiency of the autoclave and its attendant. Time consumed in heating
ROCESSES involving the Crystallization of a aolid from II.' impure solutions generally require a systematic, comparable method of control in order that the conditions for the maximum crvstallization may bo determined. For
drainage, Tlie separator is assembled in tlie follo~ving manner: The piece of GO-mesh screen is placed in tlie depression of the 4-incb pipe plug with the l/*-ineh lioles and the 200-mesh screen is placed over tlie 60-mesh s c r e e n . T h e 60-mesh screen provides a firm support for the delicnte 200mesh screen as well as d r a i n a g e space. The 4-inch p i p e plug is screwed into one of the unions and tlie union is screwed into the nipple. The other union is then screwed into the nipple and a container is tlrereby obtained. To charge the separat.or, massecuite, or the magma of crystals and mother liquor, is poured in at the top; the top plug with the airinch pipe is then screwed in and the pipe coupling tightened; air, a t any desired constant pressure from an air tank is admitted. It is not essential for control purposes that the separation be quantitative. If the ratio of concentrations of the product desired in the original magma or massecuite to that in the mother liquor or molasses separated after crystallization is known the efficiency can he computed. 1 Received
September 26, 1930.
