Air-conditioning in the Drug-Manufacturing Industry WILLIAMA.
HAnLm,
Hi I d l y a n d Company, Indianapolis, Irid.
H E X we speak of air-conditioning in t.lie nianiifacturing industries, we mean the treatment of air so that the temperature, the humidity, the volume, and the velocity are controlled. Ileatcd air, in unknowlr volumes with little regard to temperature and no regard to liumidity, has heen used in the drng-ma~iufacturirrfindustry for centuries. It would be hard to trace tlie origiii of the ordinary drying closrt or hot air chamber. Heat and circulation of air seemed to be the only requirements. Shortly after the close of the nineteenth century, air-conditioning mme int,o the drug-manufaeturin,~field. Its importance a,nd application have increased not, progressively, hut about as the sqnare of the years since 1000. It is related, and on good authority, that a certain large pharmaceutical manufacturer, struggling to make gelatin capsules (a proces always fraught with many difficulties), sent for the engineer of a fan manufacturer and asked him to assist in working out the process of drying. The young engineer, after some study, realized that only an apparatus which could turn out air with a fixed temperature and humidity would satisfy the job. Being a genius, he cnneeived that humidity could be controlled by passing the air through sprays of wat.er; by thus cooling, he could rerlnce the moisture content to the desired point. Accordingly, the young engineer designcd an air washer and convinced his customer that it vrould do the work. The customer asked for the usual guarantees of performance, hut the president of the fan company was reluctant so to bind his corporation. The result was that the drug manufacturer took tlie plans and built the air-conditioning unit, which did all that tlie engineer claimed it would do. The engineer left his joh with the fan company, organized a corporation to make air-.-(.onditioning equipnicnt, and has ever since heen one of the largest factors in the development of tlie industry.
MANUFACTURE OF CAPSULES Of all jobs of conditioning air in the drug busiiress, tlie matter of capules undoubtcdly presenkd t,he great,cit dif9
ficultiea. Tim wall or a capsule varies in tiiickness from 0.003 to 0.006 inch, depending upon tire size of the capsule. The smaller capsulcs must not have a wall thickness over 0.0035 or under 0.0025 inch. If the wall is thinner, the capsule is too fragile; if thicker, the caps will fit too tightly on the hodies of the capsules. To work ~ritliinthe%%close limits in addition to controlling the viscosity and temperat,ure of tho gelatin to be molded, the temperatore of the pin on which the capsule is to he molded must also be controlled. This is part of the role of the air-conditioning plant. Another job of the same plant with the same air a t the same time is to set the gelatin on the capsule pins immediately after the pins have been dipped into the molten gelatin. Again, the same air must dry these capsules in forty-five or fifty minutes so t.hat they can be stripped off the pins on which they have heen molded. For different sizes of capsules, different temperatures of air are required; but the moisture content, measured in grains per cubic foot of air, can be constant for the same gelatin. Close regulation of the air-conditioning plant is necessary, as the moisture content of the air should not vary over 0.25 grain per cubic foot, and the temperature not over 0.5" F. This is not eaGly accomplished when 30,000 to 60,000 cuhie feet of air per minute are condit.ioned. I n cape of both huniidity and temperature, a departure above or below the fixed limits causes trouble. I n many processes an upper or a lower limit alone is set, but with capsules both an upper and a lover limit are fixed for humidity and for temperature. The process is a closed circnit wherein the conditioned air is fed to the capsule machines, is then dissipated in the insulated capsule-manufacturing room, and is then returned l o he reconditioned. A washer, using water, cooled by refrigerating machines, and controlled antomatically to meet d l weather conditions, has made capvule manu. facturing contirruons and satisfactory. Although the conditioninC of air for capsule manufacture was one of the most difficnlt of application, it has brought largo returns both to drug manufacturers and the air-conditioning industry. Before the use of conditioned air capstiles
air-con rli t i n n i n g i n d u s t r y , mit.li the eonv ~ , y o r riianufac!tiirer, rediirnl tliiz drying time to tliirty inillrites aird coi~seThe
'1~)- IxMc in jii.;t as dry
today
iii
thirty m i n u t e s
:is it tins aEt.er the t l m e rlny Ix'riod in use t.wentp-
five years R E O . In the inilustry it is almost univers:il pract,ice for the mamif:katurer to wrap bottles i u p;irchinciit p a p e r t o p r o t e c t the Ixl)cl and t o loa~pthe bottle clean. In t t dry cold atmosphere the imcliiiient paper s liri t i k s nu11 cre.cks a n d fails to xive t h e anticipated proti!ct,ioii to the label. With simple apparatus and sinall cost the air can be so conditioned where the ~vrappcdhottles are stored t h a t t h e package can l e a v e tlie p l a n t of t h e irisniifacturer ent,irely uniirrpaired. in:! of g l a n d ~ m d r-cmnditioniiig liar played ai importallt part. Gland products are expensive, are subject to contamination, a ~spoil l ifnot given the best of treatment. The therapeutic value of iiiitiiy glands and other animal products is totally ilestroyed by processing a t a temperature aljove 25" or 30" C . (77' or 86" E.). Sir-coiiditioning, particularly during the summer rirontlis, h a s greatly rcdoccd this liaanrd and stoppcd niany the I( (.'
