High pressure closures materials

Koemer, J. P. "A New High Pressure Automated Closure System", In High Pressure Technology Material, Design, Stress Analysis and Applications, Khare, A. F., Ed. Vol. 148, The American Society of Mechanical Engineers New York, 1988 pp. 89-93. 

Crum ASD. The distribution of load over threads of a threaded closure, including temperature effects and local imperfections. High Pressure Technology, Material Design Stress Analysis and Applications, ASME PVP-Vol. 148 1988. 

The heart of the system is the oxidation vessel depicted in Figure 1. This vessel is a high pressure, 1000 cc, Hastelloy C-276, bolted closure reactor manufactured by Autoclave Engineers Inc. Hastelloy C-276 was chosen as the material of construction due to its excellent corrosion resistance to a wide variety of chemical process environments, which include processes utilizing strong oxidizers (5,6,7). The unit is fitted with 1/8" and 1/4" Hastelloy C-276 feed delivery and product outlet lines... 

In operation containers constructed of microwave-transparent materials, (e.g. quartz or fluoropolymers), are used to hold multiple samples inside the ultraCLAVE . The interior of the stainless steel vessel is protected by a titanium nitride or multi-layer PTFE plasma coating for complete acid and chemical resistance. Sample containers may be open or covered by a lid. After the samples are loaded (manually or robotically) the ultraCLAVE cover is lowered into place by an electric motor controlled from the system s PC. The vessel closure is engaged and secured in place to seal the ultraCLAVE for high pressure operation. 

Much information is available on the deformation and fatigue behavior of simple thick-walled cylinders [10-17], but it must be remembered that most process reactors will not be a simple hollow cylinder. Components such as connectors, threads and sleeves, windows, and removable closures make a complete analytical solution for a high-pressure system design problem quite involved. Useful design criteria for thick-walled vessels can be derived, however, under the assumption that the material of which the vessel is made is isotropic and that the cylinder is long (more than five diameters) and initially free from stress. The radial and tangential stresses in the walls are then only functions of the radius coordinate (r) and the internal pressure. Given the outer-to-inner wall radius ratio as o/i = w, and the yield point (To) of the material, the yield pressure (py) is... 

The supercritical drying process is carried out batchwise (see Figure 8.22). The material to be dried is inserted into a high-pressure vessel equipped with a quickacting closure at the top. The samples are soaked in the organic solvent before the... 

Various procedures have been developed (under normal pressure and vacuum) to check whether highly contaminated liquid, gel or media based material will grow back or penetrate closure systems. Variable results suggest that alternative methods to detect leakage are preferable. 

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