Fluid sealing technology

Fluid Sealing Technology, Heinz K. Muller and Bernard S. Nau... 

A recent development in sealing technology has been liquid encapsulation microspray sealing (LEMS) in which a sealing fluid of approximately 50 percent water and 50 percent... 

Recent developments and adaptations of high-speed seal technology have brought gas barrier seals into mixer applications. With a gas such as nitrogen as the barrier fluid, process contamination is virtnally eliminated, and a pressure monitor can be used to detect leaks. The problem is that gas is a poor lubricant for the seal surfaces. However, by machining swirls or pockets in the inside surface of the seal faces, gas pressure can be raised locally to lift the seal surfaces apart. 

Figure 3.45 By perforating the antitelescoping device, a small controlled bypass of fluid past the module seal is achieved to eliminate the stagnant area between the reverse osmosis module and the pressure vessel walls. This device is used in food and other sanitary applications of spiral-wound modules [115], Reprinted from Reverse Osmosis Technology, B.S. Parekh (ed.), Marcel Dekker, New York (1988), p. 359, by courtesy of Marcel Dekker, Inc.

Watts, N.L., 1987. Theoretical aspects of cap-rock and fault seals for single- and two-phase hydrocarbon columns. Marine and Petroleum Geology, Vol. 4, November 1987, pp. 274-307 Weber, K.J., 1982. Influence of common sedimentary structures on fluid flow in reservoir models. Journal of Petroleum Technology, March 1982, pp. 665-672 Weber, K.J., 1987. Hydrocarbon distribution patterns in Nigerian growth fault structures controlled by structural style and stratigraphy. Journal of Petroleum Science and Engineering, 1, pp. 91-104... 

Blow-fill technology is an aseptic process whereby the container is formed from thermoplastic granules, filled with sterile solution and sealed, all within one automatic operation. The bulk solution should have a low bioburden and is delivered to the machine through a filling system that has been previously sanitized and steam sterilized in situ. Concern has been expressed that the machine itself may generate particles. The plastic granules are composed usually of polyethylene, polypropylene or one of their copolymers and are heat extruded at 200°C into a tube. The two halves of a mould close around this tube and seal the base. The required quantity of sterile fluid is filled into the container, which is then sealed. Products packed in this way include intravenous solutions, and small volume parenteral, ophthalmic and nebulizer solutions. The... 

Automated Fluid Dispensing for Fuel Cell Manufacture Gasket and Seal Dispense Technology... 

Formed by sea water, the icy bottom seals the pontoon, and when the cisterns are empty they act as buoys and take the pontoon away from the sea bottom together with the ship. In day time, the pontoon is towed to a special dock which is the very place where all the operations of CW removal take place (making use of safe methods of dismantling, draining of fluid products, neutralising of assembled steel sections typical of atomic and missile technologies). 

This brief overview shows that it is not the material that really matters to achieve high performanees but mostly the way the fluids are managed and the stack is sealed. If Si is still the material the most eommonly used, the promising performances and technology obtained by the Fraunhofer Institute with stainless steel foils, for instance, or the ones reached with PMMA by Chan et al [55], have shown that interesting alternative technologies can also lead to funetional FCs. The table 1 summarizes the main characteristics of the previously cited fuel eells. 

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