Autoclave for Visual Observation of High Pressure Reactions W.F. CALDWELL 1 rii ericciri
T h e trend toward high pressure and high temperature cheniical reactions has necessitated the deielopment of experimental apparatus which will permit risual obsertation of conditions during the entire operation. The cquipnient described indicates h o w this result is achietetl by mean4 of a rotating Jerguson gage with clear glass on t%o sides through which light may pass. I t is housed in an insulated casing, prorided with strip heaters for raisin:! the temperature and with glass windows for viewing the temperature and pressure page. Besides seriing as a miniature autoclaie, it ma? be used for deterniining solubilities in solbents which are yolatile at atmospheric prezsure and the temperatures obtained. I t also permits the determination of solution densities under barjing condition+ of temperature and pressure.
Cya ria mid Company, Stumf ord, Con i t .
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N RECEST years resenrch on chemical reactions involving higher pressures and tempcrat,ures has created a demand on the chvmical engineer to produce a vessel in which these reactions can be observed by the eyes as they progress to completion. A search of the literature on the subject brcught to light several ingenious arrangements of sight glasses which seemed practical for viewing portions of the operations. Xone of them, however, met the drastic requirements of members of our High Pressure Division who demanded sight through all of the liquid contents, as well as a view of the top of the liquid with any solid matter contained in it. I n the petrolcum industry many liquid level gages have been used for pressures running to 105 kg. per sq. cm. (1500 pounds per square inch) and temperatures of several hundred degrees Fahrenheit. The Jerguson Gage and Valve Company helped in working out a gagc which the author could adapt to the requirements. Figure 1 shows the experimental high pressure gage, having an over-:ill length of 16 inches. The chamber is made of type 317 stainless steel, with tempered glass sight glasses Gn both sides tu permit the passage of light, with an unobstructed view of practically the entire contents. This stainless steel chamber is tapped s t eavh end for 1.27 cm. (0.: inch) N.P.T. (national pipe thread), and one end takes a 1.27-cm. S H pipe nipple connected t o a gate valve a t the discharge end (Figure 2 ) , specially machined for quick connection and disconnection of the charging bomb. Figure 3 s h o w the bomb, which is also used for receiving the contents of the autoclave when the reaction is completed. I n the opposite end of the chamber is scren-ed a Weston t.hermometer having a 6-inch stem and a range of 0"to 300' C. The long stem assures ample contact with the liquid contents and, therefore, accurate immersion temperatures. On the sides of the chamber a t the center are two 6.4-mm. (0.25-inch) K.P.T. taps. One is for a pressure gage, and the opposite one is for an explosion disk. Although this disk ruptures at a pressure appreciably higher than the maximum operating pressure, it is considered more reliable than a safety valve which might fail to function if solids blocked the operating mechanism. There were also space limitations which led to the selection of the explosion disk for this operation.
Photograph of Visual Autoclar-e
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183 12THDS./
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I
INCH NES.
1
Y
DETAIL OF SEAT IN VALVE
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ENDS TAPPED FOR I/2"PIPE DRAIN
BOLT-BAR STEEL COVER - FORGED
LASS-TEMPERED HAMBER-18-8 ST GASKET-COMSSED ASBESTOS
SECTION X-X Figure 1.
Autoclave (Dimensions in Inches)
ASSEMBLY OF'PARTS Charging Bomb Connection
Figure 2.
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Vol. 38, No. 6
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.DRILL LII i5-12 N.F. THD. PER IN. ''I
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NUT 18-8 CHROME NICKEL STEEL I REQ'D.
NIPPLE
Q
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NUT CARBON STEEL I REQ'D.
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BOMB 18-8 CHROME NtCKEL STEEL I REQ'D.
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TUBE 18-8 CHROME-NICKEL STEEL I REQ'D.
Figure 3.
Details of
the Charging Bomh
ASSEMBLY
Calibration of the v ~ s > eiiidiratwl l :I gIo5ih voiurril. (11 1Y.; I,,'., and a working capaeitp of approximately 100 w. Inc'id(~:~t:ill~.. during the process of calibrating the vessvl, i i mrinl w a l r was marked off in cubic centinicters Tvhich furnishci :111 c ~ s ~ ~ ~ l l i ~ ~ ~ t means of determining the density of solutions m d i r witlcly varying conditions of temperature arid pressurr. It is, 01 ( ' o i i ~ ~ , also possible t o use the autoclave to detcrniine .snluhilitir~~( 1 1 solids i n liquids under the same varying conditions. The unit operates a t a maximum of 200" C. and, :It this t~111perat'ure, a maximum pressure of 140 kg. per sq. rm. #:ZOO0 pounds'per square inch), with increasing pressure as the t r m p w l ture diminishes until 210 kg. (3000 pounds) is reachrd ot 20" ('.
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Figure 4. Front View (above) and Cross Section
(below) of Housing and Autoclave 1. .\utociave 2 . Valve f o r charging arid diacharging autoriare (Chapman Valve 6- Manuiacturing Co., List 990) with speci2.lly machined end (Figure 2) 3. Thermometer (!Veston Electrical Iristrument Company) 4. Pressure gage of range selected for operation in hand 80 as to secure most accurate pressure indication 6. Safety head a i t h explosion disk (Block. Sivalls & BrJ-son), 6. Sight glasses on both sides of autoclave totaling inch X 1 1 1 1 2 inches bn each side 7 . Clamp operated by thumbscrew t o permit easy insertion and removal of autoclave 1 8. Arrow indicating direction of rotation which serves to agitate
A aool
l i . Door for dosing heater housing 16 hung on spring counterbalaiices and,provided with double wire glass uindow, 19, for viewing operations within a u t o (,lave 1, as well as pressur? gage 4.
hiore~accu.&te heat contrbl over full Double range wire glass window the21. ior viewing thermometer 3 1 i s rotated
8e
Thtl unit a? a whole (Figure 4) was set up on a pipe stand, 32 Iric,ht,,?high; the motor was mounted a t the rear, and the light -\i-itrh, three-heat control su-itch, and motor switch were placed a t a cmvenicrit point on the front. Provision r a s made for in-t:tlling a f:in to circulate the heated air, but trial runs demon.t ratcti t h a t thi, fan i m s unnecessary, and it was not installed. The +ctu;il co5t of the stainless steel gage, less the attachments ilcxribed, ivas $11.5.00: the, rhect metal hcater housing with base, (loor, window, :rnd shaft ;upport totaled 5116.00. The fittingP mrntionctl are qtnnrlard rquipmrnt, and thrir costs will not he ~ * n u r n i ~ i ed ~ : i lt i ~ > w . ACKNOWLEDGMENT
This unit ivus a joint plotluct of the Development Engineering IXrision and thc High Pressure Laboratory, and credit is d w .J. H . Paden and K. C.Martin, r h o supplied helpful suggest'ions ; i d , finally, the energy arid will power so necessary to make a r i w ;ind unu-ual piccc of equipment function successfully.
