"Sicon do es not discolor under intense heat..." Left, Model ESO-1 Majestic Incinerator with smart finish of Sicon BlueGray. Below, Model C finished in attractive Sicon Aluminum
Sicon finish is applied by spray on both models. Surface phosphatized by hand wiping.
—says Bob Cox, Sales Promotion Manager of the Majestic Company, Huntington, Indiana. "Our laboratory testing has shown us," states Mr. Cox, "that Sicon fills our requirements for excellent color retention under high temperatures."
The burning of certain materials can generate heat far in excess of the normal room temperature operation of Majestic Incinerators. That's why Sicon is used—easily applied by spray —because it retains its color up to 1000°F. in aluminum or in the 500°F. range in colors. Write for Sicon Literature—today! Dept. L-4.
Sicon
®
Silicone Hi-Heat
by
Finish
MIDLAND Industrial Finishes Co. Waukegan, Illinois
Circle No. 60 on Readers' Service Card
58 A
EQUIPMENT A N D DESIGN sure while sealed in a thin plastic container. Isostatic Pressing Systems
Isostatic pressing systems of various designs having large work load capacities and high pressure capabilities are now commercially available. One such system which features simplicity of design and operational procedure is illustrated by the flow diagram. The two principal components shown are the pressure vessel and pumping system. In operation the pressure vessel reactor chamber is filled with a liquid medium such as oil or water containing a rust inhibitor. After sealing and venting, pressure is accumulated by forcing additional fluid into the chamber from the liquid reservoir. This is accomplished by a hydraulic-type, air operated pump designed to operate through the air supply normally available in most industrial plants—i.e., 90 to 120 p.s.i. Intake air is passed through an oil filter to protect the pump and valve seals while a special high pressure check valve prevents reversal of the fluid flow. Automatic pressure control is provided by the indicating contact gage that is set for the desired pressure. When this level is attained, the solenoid valve is actuated, momentarily releasing a small amount of fluid into the liquid reservoir. The pressure can be held indefinitely at any level within the capacity of the system and pressure release can be controlled at any rate. An isostatic pressing system of the type described is being used at Hoskins Manufacturing Co. for compaction of refractory metal powders. The pressure vessel, 7 feet long and 18 inches in diameter, has a 6-inch diameter by 60-inch long work chamber, and is designed for 50,000-p.s.i. working pressure at room temperature. The compactness and simplicity of the 50,000-p.s.i. capacity pumping system and controls, shown mounted in a single panel, should be given special attention. This complete isostatic pressing facility requires only 20 square feet of floor space. The efficient and economical performance of this equipment is emphasized by the fact that maintenance was not required during a three month
INDUSTRIAL AND ENGINEERING CHEMISTRY
operational period involving at least 100 pressurizations. Good safety practice dictates a barricade around isostatic pressing facilities and many designs are available in the literature (5). In the Hoskins installation, the concrete pit-type barricade was selected for ease of loading and floor space economy. Isostatic pressure vessels with work chambers as large as 16 inches in diameter and 20 feet long capable of room temperature working pressure of approximately 50,000 p.s.i. are currently available. Vessels with proportionately smaller work chambers can likewise be designed for handling pressures up to 150,000 p.s.i. Isostatic compaction facilities can also be readily adapted to mass production-type operations when quantity output requirements justify larger initial expenditures. These systems are much more elaborate than the one described above and involve the use of electric motor driven pumps in combination with hydraulic boosters and air operated intensifiers for multistage pressurization. With these arrangements maximum pressures for even the largest vessels can be obtained in a very few minutes. Quantity production installations also require quick fill and drain provisions, rapid opening and sealing enclosures, and automatic controls.
Refractory M e t a l Compaction
With the ready availability of efficient isostatic systems, production of sound and dimensionally accurate compacts depends upon development of mold filling and pressing techniques. The approach to this problem will depend to a large extent on the particular materials involved, the desired finished shape, and the required dimensional accuracy. Although some of the information presented may apply to other materials, this report deals primarily with pressing of refractory metal powders into compacts for wire and strip fabrication or consumable electrodes for subsequent arc melting. Isostatic compaction of any material into accurately dimensioned intricate shapes is a relatively unexplored field, but at least one excellent reference exists (2).
