(4c) Influence of Tray Geometry and Hydraulic Conditions on Vibration Induced Damages of Sieve and Valve Trays

The present paper is a summary of observations on failures of operating trays in various industrial applications. The affected trays include fixed valves (type SVG and SRV), movable valve trays (V1-valves and A3 cage valves) as well as sieve trays.

The different incidents are investigated to derive general indications that promote vibrations and – as a consequence - failures of the trays. The failures are analyzed with regard to valve types, special design features as well as special operating conditions that lead to the failure. The basis are operating data and pictures of the damaged trays.

Also the failure modes of the trays are investigated in detail to derive the destruction mechanism. Where possible video sequences through a sight glass were taken in operating columns to visualize gas and liquid flow as well as vibrations. These findings were compared to experimental results in a pilot plant with a transparent column.

General design features that promote vibrations in combination with special operating conditions like low liquid load could be identified. The position of all operating points in the operating range has to be carefully investigated with respect to parameters that influence tray vibrations.

Based on these findings, guidelines for potentially critical trays were derived. These include mechanical design criteria as well as process and hydraulic design guidelines.