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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.
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.
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 ...
For such sensitive cases there is a test for the metal content of a column is to inject a sample which is a mixture of 2,2'- and 4,4'-bipyridine. Because the 2,2'-bipy can chelate the metal, the shape of the peak for the 2,2'-bipy will be distorted (tailed) when metal ions are present on the surface of the silica .
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.
The history of discrete sample analysis for the clinical laboratory began with the introduction of the "Robot Chemist" invented by Hans Baruch and introduced commercially in 1959 [1]. The AutoAnalyzer is an early example of an automated chemistry analyzer using a special flow technique named "continuous flow analysis (CFA)", invented in 1957 by ...