Hold down plates

Model 805 random packing bed limiter, non-interfering
Structured packing
Bed limiters for structured packing are recommended when there is the potential for packing displacement during upset conditions.
Random Packing
Because conditions that result in the fluidization of some or all of the packing at the top of a bed are difficult to predict, a packing retention device is recommended.
An alternate method of packing retention such as anti-migration bars can be used when a deck-type liquid distributor is installed above the packed bed.