October 1947
INDUSTRIAL AND ENGINEERING CHEMISTRY
Goldthwait, C. F., hIcLaren, James, and Voorhies, 9. T., Jr.. Tezfile W o r l d , 96, K’o. 2 , 115 (1946). I I ! Grove, C. S.,Jr., Perry, J. W.,and Casey, R. S., I m . Lsii CHEM.,39, 1261 (1947). 1.51 Hess, K. P., “Textile Fibers and Their TJse,” J. P. Liypincott Co., Philadelphia, Pa., 1936. lti! Inst. of Textile Techno]., “Textile Technology Digest,” 1946. I 7 Interscience Publishers, Inc., “Xatural and Synthetic Fiber*. Literature and Patent Service,” New York, 1946. I \ \ Len-is, SV. K., Squires, L., and Broughton, G., “Industrial Chemistry of Colloidal and -4morphous hlaterials.” p. 379, New York, The Macmillan Co., 1944. 1\11 Lopata, S. L., Chem. &. X e t . Etzg., 51 No. 12, 104 (1944). P i l . Rlauersberger, H. R. (editor), “Mathems’ Textile Fibers,“ 5th ed.. John Wiley &I Sons, Inc., Sen- York, 1947. 1:3!
I
21) Ibid., p. 14. 2)Ibid., pp. 18-20.
lieyer, K. H., “Natural and Sjiithetic High Polyiners,” y , 268. New York, Interscience Publishers, Inc., 1942. 24) Xleyer, K. H., and Mark. H., “Der Aufbau der Hochpolpmeren Organischen K’aturstoffe,” Leipzig, 1930. -‘.i JIorrison, B. V., “Textile Books and Periodica!s,” 1:. S. Dept. of Agr., 1944. ?ti’, Oesterling, J. F., Philadelphia Quartwmaster Depot. private romrnunication (1947).
--____
~
._.
1215
(27) Plastics Catalog Corp., “Modern Plastics hcj-cloyadia,” Yew York, 1947. (28) Schmidhauser, O., Melliand Teslilbei., 17, 905 (1936). (29) Schrder. R. J., and DeHaan, A., Chem. En(/., 53, X o . 11, 96 (1946). ( 3 0 ) Sherman, J. V., and Sherman, S.L., ”New E’ibiw.” New York, D. Van Nontrand Go., Inc., 1946. 131) Simonds, H. R., and Ellis, C., “Handbook of Plastics,” p. 344, New York, D. Van Nostrand Co., Inc., 1943. (32) Smith, H. DeWitt, “Textile Fibers, An Engineering Approach
to Their Properties and Utilization” (Edgar Marburg Lecture, 1944),Philadelphia, Pa.. -1m. Soc. for Testing Materials, 1944. (33) Ibid., p . 3. (34) Ibid., p. 42.
(35) “Textile Bibliography,” Textile World Yeal,hook and Catalog. New York, 1941. (36) Thomas Pub. Go., “Thomas’ Register of .Iriiericari Marinfacturers,” 36th ed., Kew York. 1946. ( 3 7 ) Yon Bergen, W., and Krauss, W,, “Textile I‘ibrr at la^,'' Tostilt, Books Publishers, Inc., Sew York, 1945. (88) Waldo, W. G., Florida Ramie Prodiicts, Iric., Keu. Torb, private communication (1937). (39) Woolf, D. G., aIid (:haae, 11’. K,, Teatile W o r l d , 93, No. 9. 105 (1943). (40) \\-right, Robert, mid Harris, LIilton. “Modern Plastic5 L i i ~ ~ - c l o pedia.” C‘ltnit 8 , S e w Torb, Plastics Catalog Corp., 1947.
~~
GLASS
J. R. BLIZ-4RD, Corning
D
ES’ELOPMESTS in glass in the paat l i s year1 h i v e 1)c~eii concerned mainly with nelv products and new ways of ap;)lying them as materials of construction. The purpose of this
: , d e l e is to describe the new n-ork that is of particular interest t o (.liemica1engineers. The most useful glais for eiigineering purpo 774, generally knoxn as one of the Pyres glasses. Its phy.5ical !ir,operties are given in Table I, together Kith tho:.e of 1-j-cor high .i!ica glass 790. Glass 774 is n-idely used for indust,rial applicn*ions because it has a low coefficient of thermal expansion, about #tie third that of Kindow glass, and because its surface is iinusii:i!ly resistant to abrasion. Its low coefficient of espansion ine2iiC r t i i i t , for the same temperature gradients, it will be subjected ti-) :tilout one third the thermal stress that would occur in the ordi‘i:qry glasses. I n addition, its resistance to abrasion minimizw iiirface injuries and enables it to resist greater s t r e w s iyithout (;tilure, Resistance to chemical attack is exceptionally good, even i,ir glasses, and glass 774 can be used freely for practically any iiquids except hot caustic solutions, conrentrated hot phoq>horic :!#.*id,and hydrofluoric acid (15). The inost common application for gl 771 as a chemical ( , piirchased from t hr pipe ma:iuiacturcr. Elccti,ic waling eri:~l)li~~ the uwr to apply s t a n d w l conic. rid thu. provides field flmgrti pipe p r h b r i c a t e d pipe. Hard :rs;hcsios, rui)twr, or Teflon gaski+ can be used, and operating pressures aiid :e:iipcmturrs arc’ riot w i t r i c t d hecausc of t h ? joint. Prefabriwti’il r)r i ~ l i v ~ t r i r a iit.lrl-f~t,l.ic.xtcc~ ll~~ glas.3 p i p can 1 1 t ~ i i s e d : i t
INDUSTRIAL A N D E N G I N E E R I N G CHEMISTRY
1216
Vol. 39, No. IC
burner, and a beadlike dang:t is formed by rapidly spin ning the glass after the enc has softened. Figure 2 showt the beaded end and the manlier in which it is connectec 'o e i t h e r c o n i c a l g l a s a danges or other beaded danges. The area near the bead IC ,.ti ess-relieved in the ring burner used for the flanging operation. Total time required to cut, bead, and stress-relieve a piece of pipe is usually not over 10 minutes The operation is so simple that a competent mechanic can learn it in two hours 07 less. The beaded joint require? molded rubber gaskets and is not ordinarily used for service pressures over 26 pounds per square inch 01 temperatures over 250" F I t can be used on all sizes of pipe up to and including 3-inch inside diameter. Figure 1 . Sealing Two Lengths of Glass Pipe Together Electrically Glass pipe lines have ottaL been bpecified for services witt duidr X) rurrosire that it has been extremely difficult to find iiiiiable gsaket materials. Gaskets sheitthed with TefloE ,\polytetrafluor.oethylene polymer) have solved this problen. High Silica Borosilicate High Silica Glass 790 satisfactorily. The chemical engineer now can equip glass pipe Gla5s 790 Multiform Glass 774 lines with gaskets that are practicallv as corrosion resistant as t,hc Tolsr Clear trans- Clear trans- White parent parent opaque glass itself ($1). SDwific nravitv 2 23 2 18 2.15 The borosilicate tubing used for glass pipe is available in a wide \fax. working-temp., F. Ordinary urjage 350 1450 1300 range of sizes for use in manufacturing laboratory equipment, Special usage 700 2000 1800 Perniissible thermal shock tapered tube flowmeters, heat exchanger tubes, and many misF . " 180 1000 700 (l/4-in. plate), cellaneous pieces of plant' equipment. Range of diameters availM a x wofkine tensile stress lb./sq. i 1000 1000 780 Annealed 2000 .. Tempered inch. M'all thicknesses range from ' / l e inch for the small sizes .\Iodulus of elasticity, Ib./ inch for the heavier pieces, During the war years the sq. in. 9,750,000 9,700,000 Q,?UG,OOO up to Coefficient of thermal exdrawing machines were equipped to malie tubes up to 6l/2 inches pansion/' F. 1 8 . 3 X 10-7 4.2 X 10-4 4 . 7 X I O - * Thermal conduotjviiy, B.t.u./ in outside diameter in lengths up to 6 feet (6, 6). These larger (hr.)(sq.It.) (?)at 75' F. 8.1 9.0to 9 . 5 .).. sized are niade to order and are not ordinarily stocked. X 6 X 6 inches heated in a n oven and plunged When necessary, borosilicate tubing can be drawn with ellip3 D a t a apply t o plates h t o water. Permissible shock of 180' F. means plate can be heated t o *icnl ratlier than circular cross section. The cell cooling mil 290° F. and plunged into water a t 40° F. without breaking. 0
.
I
.
.
pressures up to 50 pounds per square inch and temperatures up t o 350" F., provided care is taken to protect the pipe from severe thermal shocks. A second method of field flanging has been developed for users whose service conditions do not require the standard conical flanged joint throughout their lines. This method, known as pipe beading, requires considerably less equipment than does electric sealing, and the entire pipe beading kit can be bought or rented a t reasonable rates (4). I n this second method the pipes are cut to length with the same tool used in the electric sealing process. Instead of sealing a new flange t o the pipe, the cut end is reheated in R ring
Figure 2.
Beaded Field Flange Connected to Standard Conical Pipe Flange
INDUSTRIAL A N D ENGINEERING CHEMISTRY
October 1947
Figure 4.
Figure 3. Borosilicate Glass Cell Cooling Coil Fabricated froni Elliptical Tubing with Flanges for Connection to l-Inclh Class Pipe
in Figure 3 was made with elliptical tubing l~ccauset,iiib ?ermitted inclusion of substantiallj- more cooling surface within ;he space allott,ed. Tube and shell heat exchangers can he equipped with thin wall glass tubes if the end sheets are designed to hold a packing t'hai d l permit the glass tubes to move slightly with respect t'o thishell. A number of successful heat exchangers of this type use wbber 0 ring packings. Photochemical reactions are being activated under pressure b j iltraviolet lamps encased in light wells made of borosilicate glass xbing. The wells can be equipped Kith flanges for making pres. wre-tight connections in the reactor, or they can be introduced -,hrough stuffing boxes. Reasonably good efficiency is possible 3ecause glass 774 transmits a substantial part of t h e near ultraviolet. A 2-mm. thickness transmits 1Oyoof the incident light A t 300 mp, and 70% a t 330 mg, and goy0at 370 nip (16). Hand-blown borosilicate glass cylinders are made in sizes from 5-inch o.d. up to 231,'2-inch o.d. Table I1 lists the sizes end ,mgths most frequently produced (8j. Chemical cnginerra oftrir \riur\ii
TABLE
11. FREQCENTLY U S E D SIZES O F GLASS CYLIA-DERS
Outaide
Nominal Wall
In. 7
In
Diameter.
8 91/8 10 11 12 13 14'/4
16
Thickness, '/a to I / ,
'/a t o
i/4
'/l6
to S / 8 t o "8 to $/a
'/1#
60 l / Z
1/18
'/n
r / a to I/:
'/a t o
P/U to
'/¶
'/n
1217
High Silica Glass Sheath on a T h e r m o ~ ~ m p l e
~ i a eiaIye glads cylirltiws to rnake observation sections in pilor plant fractionating columns. Entire fractionating columns can be built with glass cylinders when chemical att'ack is exceptionally se,verP or when reactions can be accelerated by the admission of light. Flat-bottomed borosilicate glass jars are available in sizes a> large as 16-inch 0.d. X 36 inches long, and 18-inch 0.d. X 1 F inches long (9). These have been used as the bodies for el(:('trolytic cells because they are much less vulnerable t,o temperature stresses than other ceramic coritairiers of the sa,me size. Borosilicate plate glass has become available recmtly in thicknesses of 3/16, 1/4, and 3/8 inch, and it is expected that '/2-incL sheets will also be in production by September or October of 1947 Sheets are normally smaller than 24 X 30 inches, but it is possible, by special order, to obtain sheets as large as 24 x 60 inches. ApDlications include lotv pressure sight glasses, furnace and oven door glasses, and occasionslly sucli unueual purposes as crane cab windows in steel mills. Molded sheets and slabs of borosilicate g l a s are made in thicknesses up to 1,/4 inch. These heavier pieces are ground flat and polished for use as sight glasses in prsssure vessels. Molded sight glasses are made in several standard sizes ranging from 2l/p to 8-inch diameter for low pressure service and from 4t'o 83/&ch diameter for pressures ranging between 1.50 per square inch for the former and 30 pounds for the latter gliss. When necessary, these glasses can be strengthened by tempering, an operation that, doubles i-heir maximum safe working pressures ( 7 ) . Molded borosilicate glass godet v.-iieels ( 1 ) are used in the viscose myon industry t o draw the wet fibers out of the arid baths. G l a ~ *as selected for t'his purpose because of its corrosion resistance rnd because it offered a smooth. abrasion resistant surface thai wquired no finishing operatiour subsequent to molding. Other synthetic fiber manufacturers are experimenting Lvith glase rollera and pulleys for similar application>. lloldcd borosilicatt glass parts are usually inespcnsive if they are bought, in quantitiet of 2000 pieces or more, depending upcln the part in quePtion (19). Clear high silica glass 790, known as Vycor. is a relatively new product that chemicd engineers are finding useful for high temTI' I!O. 17). Tt. propcrtiw a r e ;dinosi tlir. w ~ i n i ~
~OROhILICATE
h I a xi m u 11 Length. In 24 16 24 20 19 24 23 28 24
Figure 5 .
High Silica Glass Pachine Support Plate I l a d r by \lirltifnrrn Prim=-
1218
INDUSTRIAL AND ENGINEERING CHEMISTRY
Vol. 39, No. 10
acid coalescers. 1 50-inch-diameter packed column 32 feet high filled with glass fiber mathas been very successfully used for production oj 191.5 proof alcohol from high wines (14). Somr of the advantages realized in this installation in particular were good rectifying performance, Ion pressure drop a t high vapor velocities (5 to 6 feet per second), low holdup, consistent behavior lighr reight per unit volume, and low cost. Fibrous glass tower packing has b t w t1~t.11 successfully as a coalescing agent in a prows. for desalting petroleum (2, 22). Its large suriarv area, ranging from 135 square feet per cubic foot at a density of 3l/2 pounds per cubic foot t o 232 square feet per cubic foot a t a density of 6 pountilj per cubic foot, is an important factor in this appllration. Filter cloths of glass are valuable where h i g l ~ l ~ acidic or mildly alkaline fluids destroy ordinan materials, or where fluid temperatures are CAYceptionally high (18). Foamglas, a cellular insulating material made by the Pittsburgh Corning Corporation, offer. the chemical rtigineer a highly corrosion-resistani low temperatuie insulation. Its thermal contluctivity a t 50" F. is 0.40 R t.u. per hour per squirt foot per O F . per inch (LO). Industrial floats can be made of Foamgla. .mce its specific gravity is only 0.17. Being trui glass, these floats are flee from chemical attack I)\ most liquid\.
Lrrm.4rLltmCITED (1) Blizarb. J. K.,LVnc.hi~lcDesign, 17 (lo), 137.--%c
Ucohnl Diatillation Coliiniii Ueiiip €'ached v i 111 (;las- Filwr. Each of the rerips of grids above the pockrrs' heads is lowered layer of packing is rompletrd.
(1945).
12) Burtis, T. A,, a:rd Kirkhride, C. Q., Trnus. Am. Inst. C'hem. Epigrs., 42, 413-39 (194fG (3) Corniiie Glass Works. Bull. IA-3 (1946). (4) Corning Glaaq W m Bs, B d l . IA-22'(1947) Uorniiig Glass Works, Bull. IF-3 (1946).
inlo p o n i t i u v , t m vrlq 11
as those of f i m d silica, as wuuld lie espectcd d i m i: i y !l!i' ,- Sic ). Its physical properties are h t e d in Table I. The most iniportant property of glass 790 is it,s ability l o withstand operating temperatures as high as 900" C. and t,hernial shocks as severe as that occurring when a red-hot cruciblt iplunged into ice water. One obviouv application for high silica glass is in high tempcraAnother is for thermocouple protection tub?: ( 2 3 ) . Here the glass, being transparent, transmits radiant, energy to the couple without appreciable lag and allows the furnarc, to be more closely controlled. The tube is also impervious to tlii furnace gases and consequently increases thermocouple lifr I>> protecting it from corrosion. High silica glass jars are uscd as containers in a mineral calci~iing operation at temperatures between 700" and 1000" C. FIi@ silica glass tubes are used for gas sampling and as sheaths f i x ininiersed electric heaters. Since i t is difficult t o make clear high silica gla.ss in w*tioii> thicker than to inch, it is necessary to make 1imvit.i pieces by a technique called the Multiform process. This consists of pulverizing the clear glass and casting or aimilarl!forming shapes that are subsequently refired. It is possible h \ this process to make heavy perforated plates for packcd columns, large crucibles, heavy guide rollers, etc. Althougi: this operation is limited to relatively simple shapes, not exccctling about 18 inches in any dimension, it has produced many useful parts that could not, have been obtained otherwisp. Figure 5 shows a typical product of the hfultiform process. Fibrous glass has been found to be exceptionally well suited as t~ material for parking distillation columns, scruhhing t,owrs, and
I:,
(bi
Corning Glass Works, Bull. IG-1 (1947).
( 7 ) Corning Glass Work-. BUZZ.IB-20 (19471. Corning Glass Works; Bull. IH-3 (1946): Corning Glass Works, Bull. IPI-4 (1946).
Corning Glass Works, BuZl. IK-9 (1946). Funke, A. H., and Blizard, J. R., Fond Inds., 16 ( 2 ) ,90-9 (1!+4'. Guyer, E. SI., Electronic Inds., 5 (12), 65-7 (1946). Guyer, E. M., Electronics, 18 (6), 93-6 (1945). Minard, G. Vi-.,Koffolt, J. H., and Kithrow, J. R., Trnn Inst. Chem. Erigrs., 39, 813-51 (1943). l l o r e y , G. W.,"Properties of Glass," pp. 108, 120, 134, NvuYork, Reinhold Puh. C,orp., 1938. Ibid., 433, 434. Nordherg, &I. E., J . Am. Ceramic SOC.,27 (lo), 299-305 (1944 . Owens Corning Fiherglas Corp., Bull. D5.5.2(Dec. 19, 19431. Phillips, C. J., "Glass, the Miracle Maker," Chapters 8 m i i 9 New Yolk, Pitman Pub. Corp., 1941. Pit,t,aburgh Corning Corp., Bull. G-2508 (April 1946). IIeiifrew, 11,XI., and Lewis, E. E., IXD.EXG.C H m c . , 38, 870 -i (19461. See, XI. J., Lindahl, J . P., Taliaferro, H. R., and Harte, C. I t . , .Jv.. Prtroleunz IZefiner, 25 (4). 1 3 - 4 0 (1946). \'ollrath, J . P., Instrurnentntioir, 1 ( 2 ) , 14-15 (1944). lyhitehiirxt. R . K., ChPm. & M e t . Enq., 53 ( 7 ) , 112-15 ! l ! i l l i i
