Plating design limitations

Most common geometry Small sample size Easy to clean Various plate designs Limitations Non-uniform shear rate Low to moderate shear rates... 

The frame plates are typically epoxy-painted carbon-steel material and can be designed per most pressure vessel codes. Design limitations are in the Table 11-18. The channel plates are always an alloy material with 304SS as a minimum (see Table 11-18 for other materi s). 

Design Standard channel-plate designs, unique to each manufacturer, are developed with limited modifications of each plates corrugation depths and included angles. Manufacturers combine their different style plates to custom-fit each seiwice. Due to the possible combinations, it is impossible to present a way to exactly size PHEs. However, it is possible to estimate areas for new units and to predict performance or existing units with different conditions (chevron-type channel plates are presented). 

The sieve-plate design is limited by the need for cooling coils. The tray design must ensure that the cooling coils sit easily in the layer of liquid. Therefore, the minimum weir height available was 40 mm. Despite this initial constraint a satisfactory tray design was developed. 

These two types of flooding are usually considered separately when a plate column is being rated for capacity. For identification purposes they are called entrainment flooding (or priming ) and downflow flooding. When counterflow action is destroyed by either type, transfer efficiency is lost and reasonable design limits have been exceeded. 

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