Heat exchangers plate-and-frame

FIG. 11-49 Plate-and frame heat exchanger. Hot fluid flows down between alternate plates, and cold fluid flows up between alternate plates. Theimal Division, Alfa-Laval, Inc.)... 

Figure 2.20 Austenitic stainless steel plate from plate-and-frame heat exchanger. The orange oxide was formed from corrosion product originating at the regularly spaced pits. Pits are present near points of contact between adjacent plates. Corrugations run at right angles on adjacent plates.

Stainless steel corrugated plates from a plate-and-frame heat exchanger. Closed chill water cooling loop used to cool continuous caster mold. 

Other types of plate-and-frame heat exchangers are double-wall-plate exchangers, welded-plate exchangers, wide-gap-plate exchangers, and brazed-plate exchangers. Each type is briefly described below. 

This type of filter allows pressurized filtration of a slurry mixture to remove solids. A set of filter plates is sandwiched together in series with a configuration similar to the plates on a plate-and-frame heat exchanger. After the plates are compressed... 

Figure 10-7. Plate and Frame heat exchanger basic components. (Used by permission Alfa Laval Thermal, Inc., Bui. G101)...

Plate and frame heat exchangers are also very susceptible to problems of scale or other types of fouling, resulting in a rapid falloff in the flow of circulating water. Complete blockage may occur, but the individual plates can be easily split apart on the frame and mechanically or chemically cleaned. 

For indirect heating, the plate-and-frame heat exchanger is generally more effective than the shell-and-tube type for heat transfer due to its larger heat-transfer area. However, the former is limited to lower pressures (normally less than 20 atm) due to its weak structural strength compared with the latter. The plate-and-frame type is also favorable for the sterilization of a high viscous system. 

A shell-and-tube or a plate-and-frame heat exchanger can also be employed for cooling. The temperature versus residence time relationship for cooling using an isothermal heat sink is... 

Sterner D, Sunden B. Performance of some plate and frame heat exchangers as evaporators in refrigeration systems. Proceedings of the 5th UK Heat Transfer Conference, IMechE, 1997. 

They are avoided by cooling the recycle acid in water cooled shell and tube or plate and frame heat exchangers. 

A plate and frame heat exchanger is sometimes used to preheat incoming soap lye, as treatment is more effective with warm lye. The plates can be of 316L stainless steel, or even titanium for effective corrosion resistance. 

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