Whilst in principle, the DYNA-VALVE functions as a movable disc that adjusts the tray open area to accommodate vapour load variation, just as conventional 3 legged valves,
it offers the following additional benefits:-
- Incorporates an anti-rotation feature.
- Extra robust legs to reduce valve losses in service.
- Easy-fit design for quick
replacement of missing valves without
requiring special tools. (Snap-in) .
When the trays are designed
for maximum approach to the entrainment limit at design vapour load, design
efficiency will be maintained with turndown to around 10% of design loads.
Alternatively, where low tray pressure drop is a design limitation, the
trays can be designed to operate close to the minimum orifice velocity
providing that high turndown is not required.
If operation at low
vapour rates is anticipated, trays are fitted with two different gauges
of valves. As the vapour rate is reduced, the heavy valve units will close
first with the light gauge valves fully open. This avoids instability
and valve wear by reducing the tendency of the valves to operate in the
half open position.