A PORTABLE HIGH PRESSURE Where space is limited and high pressure research equ$ment is needed at infrequent intervals
C. M . SLlEPCEVlCH
R. L. PORTER
ven for the most rigid safety requirements, design
E standards can be determined for self-contained high pressure laboratories. But unfortunately the cost is sometimes too high for the type of research to be undertaken. Often, a cheaper facility is needed for preliminary studies or occasional one-shot tests. T o fulfill this requirement, a small barricaded enclosure was developed, which is safe, inexpensive, portable, and in appearance conforms to the high architectural standards demanded in most research laboratories. Appearance, it was felt, presented no problems other than adding modestly to the cost. On the other hand, portability and cost certainly depend on satisfying the safety factor. A number of panels were tested: steel plate of various thickness; steel and wood sandwich; steel, sand, and steel sandwich; spaced steel plates; glass fiber mats bonded to steel; and blasting mats. Although all were suitable against equipment failures, factors such as weight, cost, durability, fire resistance, or appearance eliminated most of them. The most promising was a '/%-inch thick glass fiber panel, consisting of 30 laminations of mats laid-up with polyester resin and bonded with epoxy resins to 3/1,3inch thick steel boiler plate. Sa-era1 of these panels
C. M . Sliepceuich is Associate Dean of the College of Engineering at the University of Oklahoma and R. L. Porter is Engineering Sales Manager for Autoclave Engineers, Inc., Erie, Pa., which provided financial support and laboratory facilities f o r conducting these tests. Frank Loving of Du Pont provided spec$cationsfor the explosive charges. John P. Tansey of General Welding Co. supervised fabrication of the cell; Seargent Ken Ambler conducted the tests involving explosive charges; and Du Verre, Inc., fabricated the glassfiber mats. T h e barricade is now commercially available, but the manufacturer limits its warranty to repair of defects in materials and workmanship only. AUTHORS
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INDUSTRIAL A N D ENGINEERING CHEMISTRY
were subjected to direct gun fire at point blank range (10 to 20 feet). A .45 caliber pistol bullet made no penetration except that the bullet jacket imbedded itself in the outer layers of glass fiber. -4 12-gage rifled slug passed through the glass fiber and bulged out the 3/le-inch steel wall slightly, but without penetration. A .30 caliber rifle, 180-grain bullet, having a muzzle velocity of 2700 feet per second penetrated both the glass fiber and the steel wall. A full-size, barricaded cell was then constructed for testing under equipment failure conditions. A number of special features to suit individual needs can be incorporated in the basic daqign without detracting from its utility and safety. Fire Tests
About two quarts of acetone was splashed o w r the walls and floor of the cell to simulate chemical spillage. The blasting mat door was closed and the acetone ignited. The doorway completely blocked the fire, and the only persistent flame occurred in places where the insulation had been broken by shrapnel from former tests. One badly damaged joint on the front continued to burn for some time, and was extinguished with dry powder. In a more rigorous test, about 4 gallons of gasoline was splashed throughout the interior. Rags and paper soaked ivith kerosine were placed on the floor; the mat door was closed and the kerosine was ignited. Flames coming throuqh the door could have been hazardous to other equipment, but they did not go through the blasting mat mesh. They escaped only at points where the mat no longer fit snugly hecause of damage from previous experiments. The glass fiber is a good insulator-the flames were intense but the outside walls did not get too hot to touch. Fire continued in areas between the glass matting and wall which were damaged in previous tests. Fumes were quite pungent and lasted a long time after the fire was extinguished.
LABORATORY
THE BARRICADE CELL IS SAFE, PORTABLE, AND INEXPENSIVE It weighs only 300 pounds and can be used to confine pressure equipment having a volume up to 2 liters or l/* gallon. Rule of thumb is that volume of the cell should be at least a thousand times larger than that of the equipment to be tested.
The m.1, 72 inches high, 60 inch mZe, and 30 incher deep, can ba cad9 moved through a standard laboratory door. The iwmrmart pmUl ispurposdyplaccd abow cya level
. Back. A .45 cah'bupistol bullat,Jircdpoirzr blank> frbu tn,z i but mad#no irnptssioonon the boilupla&
The next two pages show how this small high pressure laboratory was tested to failure VOL 54
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EXPLOSIVE PRESSURES OF EXPANDING GASES Two tests were carried out which left the cell substantially undamaged. I n one test, a 1-gallon, 3000-p.s.i. reaction vessel, equipped with a safety head assembly having a rupture disk set to burst at 2050 p.s.i. and 72°F. was pressurized until the disk burst. In the second test, 2 ounces of 60% dynamite exploded with a fuse, blew the blasting mat from its tracks. Except for fine marks from rising dust no damage was done.
SHRAPNEL A pressure bomb made of a 6-inch section of 2-inch Schedule 40 steel pipe with malleable iron caps was packed with 2'/' ounces of 60% dynamite. This bomb, placed horizontally on a shelf inside the cell and was ignited with a fuse, was completely shattered by the explosion.
1 Indarmtiw imide thc cell show force of th explosion
Aslnndmdfubingplug m a plmtd abooa a rupture did ".in the safdy hod of the same au&claue that was uscd for the prior test. T h plug pmhntcd the ceiling about '/a imk but did not break through the glassfber mat. After thc tcst, it was found MI thcpoor outside thc cell; howaver, thc blasting door mat was mt romplately closed and thc plug probably went through the opcn. . p. . . ing after hitting the ceiling
Th6 blasting mat was blown uff itc IT&, but except for biecm that want thouth
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SIMULATED EQUIPMENT FA1LURE The barricade was r e l i e d with a bisphenol polyester binder, and to reduce the possibility of fire and toxic vapors, this resin was covered with an outer coating of a fire-retardant resin combined with antimony trioxide. Even though previous tes'ts may have weakened the plate or welds, no reinforcement was made. However, the sliding door blast mat was reinforced and rehung. The pressure equipment was a standard 1-liter autoclave of Type 316 stainless steel having a working pressure of 5000 p.s.i. at 650°F. Smokeless powder (177grams) was placed in the vessel and the cover was secured in the normal manner, using 100 foot-pounds of torque on each of eight bolts. A fuse was passed through one opening, but all other openings were closed.
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INDUSTRIAL AND ENGINEERING CHEMISTRY
The autoclaua whichgmaltd n p r t s w a estimated at 30,000 p.s.i. WUJ completely dismontlcd
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a
A larger bomb was made. This one, fashioned from a 12-inch section of 2-inch Schedule 80 stocl uiue. closed
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I
r
Aftar all f a t s w m complded, exterior of the barnmi# rnnainrd nrbrf&'olly intact
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