Closing coil

The 2NO contacts of the limit switch are wired in series with the closing coil of the interrupter (Figure 13.45). As soon as the spring is fully charged these contacts change over to NC and the closing coil circuit gets ready to clo.se. 

The charged closing spring may be released manually or electrically by energizing a closing coil as shown in Figure... 

The stiffness of a closed coil spring is given by the expressions ... 

A closed coil spring made from polypropylene is to have a steady force, W, of 3 applied to it for 1 day. If there are 10 coils and the spring diameter is IS mm, estimate the minimum diameter for the spring material if it is to recover completely when the force is released. 

For many polymers, as one moves from a good solvent to poorer solvent, the extent of close coiling increases resulting in a decreased viscosity because the more tightly coiled polymer chains now reside in fewer flow planes (Figure 7.6). A similar phenomena can occur as the temperature is decreased (above Tg) since the available energy for chain extension becomes less. For some polymers additional specific mechanisms are in action. 

The development of HSCCC was initiated by the discovery that when the type J planetary motion is applied to an end-closed coil coaxially mounted on the holder, the two solvent phases are completely separated in such a way that one phase occupies the head side and the other phase the tail side of the coil. This bilateral hydrodynamic distribution can be utilized for performing CCC, as illustrated in Fig. 4, where all coils are each schematically shown as a straight tube to indicate the overall distribution of the two phases. 

Fig. 4 Mechanism of high-speed CCC (a) bilateral phase distribution in an end-closed coil (b) two elution procedures for high-speed CCC (c) dual CCC system.

Closed coil helical, and C7-type stub bundle... 

Scheme (1) uses a partial reboiler at the bottom of a plate-type stripping column, generating vapor by the use of steam condensing inside a closed coil. In Scheme (2) the reboiler is omitted and live steam is injected directly below the bottom plate. Determine the number of stages required in each case. 

Because of its high MWt, P(ANi) in solution has been said to take on "close-coiled or "expanded coil" configurations, studied in some detail by MacDiarmid and coworkers [580]. 

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