Rotary valve four port

Multi-Port This term refers to any valve or manifold of valves with more than one inlet or outlet. For throttling control, the three-way body is used for blending (two inlets, one outlet) or as a divertor (one inlet, two outlets). A three-way valve is most commonly a special globelike body with special trim that allows flow both over and under the plug. Two rotary valves and a pipe tee can also be used. Special three-, four-, and five-way ball-valve designs are used for switching applications. 

By far the most common method of sample injection is through the use of a rotary valve. These are typically four- or six-port devices which allow the sam-... 

FIGURE 6.9 Schematic representation of loop-based introduction involving a six-port (upper) or a four-port (lower) rotary valve. Left and right portions = load and inject positions S = sample L — sampling loop a, b (lower portion) = sites for loop insertion C — carrier/wash stream M — towards manifold W = waste. 

The so-called four-way or hexagonal rotary valve (Fig. 6.5a) consists of six ports (three Inlets and three ouiets) and can adopt two positions. In the filling position, the sample enters the valve through port 2, fills the sample... 

The external sample loop of a rotary valve may, beside serving as a simple volumetric cavity accommodating a selected sample volume, be split or nested in order to perform more sophisticated functions (Fig. 5.10). So far only individual components, such as columns, dialyzers, and gas-diffusion units, have been nested in the loop, but it is likely that in the future a series of components, perhaps even an entire FI A microsystem, will become nested in a loop to perform a complex assay. Although a four-port rotary valve scheme was used in this section to review the techniques, it should be kept in mind that a sample loop can be split or nested equally well when mounted in a six-port valve—as implied in the previous section (Fig. 5.8)—or in the Brazilian commutator [1060]. Among many such schemes, new exciting techniques will undoubtedly be discovered. 

The rotary valves are two-position stainless-steel valves (Valeo Instruments, Inc.) with four to ten ports. The first two valves, 1 and 2 in Fig. 23-1, which are exposed to seawater, are made of Hastelloy C-22, a seawater resistant nickei-chromium-molybdenum alloy. The three valves in the heated zone (3, 4 and 5), if installed inside the GC oven, are equipped with high-temperature rotors, specified by the manufacturer (Valeo) to operate at temperatures up to 340 °C. AU valves can be actuated electrically for various degrees of automation. 

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