Computer integrated manufacturing technology can be well-served by a predictive monitoring system that would prevent a large number of sensors from overwhelming the electronic data monitoring system or a human operator. The essence of the method is to select only a few of the many sensors in the system for monitoring at a given time and to set alarm levels of the selected sensor outputs to reflect the limit of expected normal operation at the given time. The method is intended for use in highly instrumented system that includes many interfacing components and subsystems - for example, an advanced aircraft, an environmental chamber, a chemical processing plant, or a machining work cell.
The predictive monitoring method would be implemented in a computer system running artificial intelligence software, tentatively named PREMON. The predictive monitoring system would include threee modules: a casual simulator, a sensor planner, a sensor interpreter.
(S. Soloman, Sensors and Control Systems in Manufacturing, pp.314-315)
Gas Transfer Pumps
Vacuum pumps may be divided into two broad categories: gas transfer pumps and entrapment pumps. Gas
transfer pumps remove the gas molecules from the pumped volume and convey them to the ambient in one or
more stages compression. Gas transfer pumps remove gas permanently.
Gas trensfer pumps may be further subdivided into positive - displacement and kinetic vacuum pumps. Rotary
mechanical and Roots pumps are important examples of the positive - displacement variety. Diffusion and
turbomolecular pumps are the outstanding examples of kinetic vacuum pumps. Among the entrapment pumps
commonly employed are the adsorption, sputter-ion, and cryogenic pumps. Each pump is used singly or in
combinations. Pumps do not remove the gas molecules by exerting an attractive pull on them. Yhe molecules are
unaware that pumps exist. Rather, the action of pumps is to limit, interfere with, or alter natural molecular motion.
We start this brief survey of some of the more important pumps with the positive - displacement types.
(M., Ohring, The Materials Science of Thin Films, p.62)
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