Segmented Demister Pad RFQs: What Must Be Defined Before the Supplier Chooses the Section Layout?

Large mesh demisters are usually too large to pass through a vessel manway in one piece.

They must be divided into segments.

The segmentation should not be decided solely by the manufacturer after the order.

The buyer needs to provide the installation constraints that control the layout.

Actual Vessel ID

The final assembled demister must fit the vessel.

Provide:

actual inside diameter or required assembly dimensions.

Manway Clear Opening

Nominal manway size can be misleading.

The supplier should know the real usable opening through which each segment must pass.

Mesh Pad Thickness

Thicker pads can be more difficult to bend or maneuver through access openings.

Pad thickness therefore interacts with the section size.

Frame Construction

The supplier should know whether each section uses:

mesh only, edge frame, support grid, or integrated frame.

This affects segment dimensions and rigidity.

Maximum Section Weight

Site handling may place a practical limit on section weight.

If lifting equipment is limited, communicate this during quotation.

Assembly Method

The technical offer should identify how adjacent sections are:

joined, supported, or held in place.

The site crew should not have to invent the assembly method.

Support Interface

The supplier should know the dimensions and position of:

existing lower support and upper hold-down.

If these are included in supplier scope, state that explicitly.

Section Identification

Every piece should be marked to match the assembly drawing.

For example:

A1, A2, B1, B2,

or another simple system.

Packaging

Segments should be packed so that the mesh is not permanently compressed.

The shipment arrangement should also help the installer locate parts in sequence.

Engineering Takeaway

Segmented demister pads must be designed around actual access and installation constraints.

The vessel ID, clear manway opening, pad construction, section weight, support interface, joining method, and marking should all be known before fabrication.