Decreasing the number of rows of caps through which the liquid flows or by decreasing the velocity of liquid flow past the caps or by reducing the distance along the tray through which the liquid must
All of these
Providing a higher skirt clearance or a higher weir
Using split flow, radial flow or cascade flow for column diameter large than 4 ft
Tie rods are fixed at one end in the tube sheet by making blind holes and the minimum number of tie rods is 4 with at least 10 mm diameter
Clearance between shell & baffles and between tube & baffles should be minimum to avoid by-passing of the fluid, but it should be enough to permit the removal of tube bundle
Baffles are supported independently of the tubes by tie rods and positioned by spacers
Bracket supports are used for horizontal shell, while saddle support is used for vertical shell
Maintenance cost for valve and seive trays are comparatively more than bubble cap tray due to their relatively complicated construction features
Murphree efficiency of all the three trays are nearly equal, however the peak efficiency is generally higher for seive and valve trays than the bubble cap
Valve trays have the highest turn down ratio (i.e. the ratio of the highest to the lowest vapour flow rates) and thus provides the maximum flexible operating range
Bubble cap trays though most expensive are the best in situations, where low vapour rates is to be handled and a positive liquid seal is essential at all flow rates
EXAMIANS