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The four-way valve or four-way cock is a fluid control valve whose body has four ports equally spaced round the valve chamber and the plug has two passages to connect adjacent ports. The plug may be cylindrical or tapered, or a ball.
Flow injection analysis (FIA) was first described by Ruzicka and Hansen in Denmark in 1974 and Stewart and coworkers in United States in 1979. FIA is a popular, simple, rapid, and versatile technique which is a well-established position in modern analytical chemistry, and widespread application in quantitative chemical analysis.
Layers of protection analysis (LOPA) is a technique for evaluating the hazards, risks and layers of protection associated with a system, such as a chemical process plant. In terms of complexity and rigour LOPA lies between qualitative techniques such as hazard and operability studies (HAZOP) and quantitative techniques such as fault trees and ...
P&IDs are originally drawn up at the design stage from a combination of process flow sheet data, the mechanical process equipment design, and the instrumentation engineering design. During the design stage, the diagram also provides the basis for the development of system control schemes, allowing for further safety and operational ...
Three-way valves may be used in pairs to operate a double-acting cylinder, thus replacing a four-way valve. A primary function of the 3-way valve is to save/store air that's compressed in high cyclic applications. 4-way valves are used for systems that require higher air pressure. [3] Four-way valves are the most commonly used components for ...
Process analysis initially involved sampling the variety of process streams or webs and transporting samples to quality control or central analytical service laboratories. Time delays for analytical results due to sample transport and analytical preparation steps negated the value of many chemical analyses for purposes other than product release.
A sampling valve is a type of valve used in process industries that allows taking a representative portion of a fluid (gases, liquids, fluidized, solids, or slurries) to test (e.g. by physical measurements, chemical analysis, microbiological examination), typically for the purposes of identification, quality control, or regulatory assessment.
A process flow diagram (PFD) is a diagram commonly used in chemical and process engineering to indicate the general flow of plant processes and equipment. The PFD displays the relationship between major equipment of a plant facility and does not show minor details such as piping details and designations.