Process Equipment and Plant Design
Pressure drop due to pipe fittings can be estimated by the equation, ΔP/p = 4f.Le/D.V2/2gc, where, Le = equivalent length of straight pipeline which will incur the same frictional loss as the fitting and D = diameter of the fitting. The value of Le/D (dimensionless) for 45° elbow and 180° close return bends would be respectively around
The pressure drop due to the caps & slots and the static submergence should be as high as practicable for reasonable operation
The dimensionless ratio of liquid gradient to pressure drop head caused by the bubble cap assembly should be less than 0.4
Tendency towards stable operation is increased by increasing the skirt clearance of the caps, lowering the rate of liquid flow per unit plate width or increasing the spacing between the caps