Sieve Trays
Perforated tray assemblies for specified vapour–liquid contacting duties. ATTOMO reviews the operating envelope and mechanical details before defining the sieve-tray scope.
Process and equipment approach
Vapour passes through holes in the tray deck and contacts the liquid. Sieve trays have a relatively simple construction with no moving valves. At low vapour rates, weeping can limit operation, so turndown must be evaluated for the particular duty.
Applications and product requirements
Sieve trays provide vapour–liquid contact through perforations in a tray deck. They can be considered where a relatively simple construction suits the process and operating range. The liquid normally travels across a crossflow tray to a downcomer while vapour rises through the holes.
Equipment and operating approach
At adequate vapour load, flow through the holes supports liquid contact on the deck. At low load, liquid can weep through the perforations; excessive load can increase entrainment or flooding. Hole area, deck layout, downcomers, weirs and tray spacing require coordinated design. Hole dimensions must be calculated rather than copied from a generic catalogue range.
Simplified equipment illustration — not a fabrication drawing or project photograph.
Define the right package.
The quotation defines the included equipment, services and battery limits.
- Perforated tray decks
- Downcomers, weirs and supports as specified
- Installation hardware and dimensional records
- Material and fabrication documentation
Materials and configuration
ATTOMO’s scope can include punched tray panels, downcomer parts, supports and hardware to an approved design. Specify material grade, thickness, corrosion allowance, tolerances and inspection. Replacement work needs actual shell dimensions and existing support details, especially where access requires panels to be assembled inside the column.
Utilities and operation
Provide the load envelope, fluid density, viscosity, surface tension, solids and foaming behaviour. Cleaning and inspection access should match fouling risk. A sieve tray’s simplicity does not establish a guaranteed operating range or suitability for every slurry.
Information for your enquiry.
Share the information you already have. Early-stage enquiries are welcome.
- Vapour and liquid loads, including turndown
- Column diameter and tray spacing
- Fluid properties and fouling tendency
- Required material and pressure-drop limit
Frequently asked questions
Do sieve trays always provide the highest turndown?
No. The lower operating limit depends on weeping and other hydraulic constraints. Different tray types should be compared on the same duty.
Can the hole pattern be selected from column diameter alone?
No. Process loads, fluid properties, pressure drop and liquid distribution also affect the design.
What causes sieve-tray weeping?
Vapour flow may be too low to support the liquid above the perforations. Hole area, liquid head and operating conditions all influence the onset.
Do sieve trays have moving valves?
No. Vapour passes through fixed perforations. This distinguishes them from floating-valve trays, whose movable elements respond to vapour load.
Can a sieve deck use a standard hole size?
Hole size and open area must suit the hydraulic and fouling basis. Use the approved tray design rather than a universal dimension.