Custom Demister Pads for Gas–Liquid Separation

How a knitted mesh mist eliminator works

Entrained droplets deviate from the gas path through inertia, contact the wire or filament surfaces and coalesce into larger drops. Collected liquid drains through the pad along the designed drainage path under gravity.

At low gas velocity, inertial capture of some droplets can be insufficient. Excessive gas or liquid loading can hinder drainage and cause flooding or re-entrainment. These are related but distinct effects. Operate within the gas/liquid loading and velocity window confirmed for the installation; being below a flooding limit alone does not guarantee separation efficiency.

Separation efficiency and pressure drop

Separation efficiency is a design estimate or project target, not a routine individually measured factory value. Wire size, mesh density, pad thickness, droplet-size distribution, gas/liquid properties, liquid load, velocity and installation all affect the result. Density alone is not a selection rule.

Agree the target droplet size, size-specific collection efficiency, flow range and allowable operating pressure drop for each project. This page does not publish a universal minimum droplet size, removal percentage or wet pressure-drop guarantee. Dry and wet pressure losses must be distinguished; structural differential-pressure capacity also requires separate confirmation.

Cleaning and replacement

Choose a cleaning method for the contaminant and every component material. Follow vessel isolation, access and handling procedures before removing segments through the manhole.

• Water or compatible process-liquid rinsing: controlled low-pressure washing along a suitable drainage direction.
• Chemical cleaning: select the agent, concentration, temperature and contact time for the deposit and complete assembly.
• Steam cleaning: only after confirming the temperature suitability of mesh, grids, fixings and combination materials.
• Soaking and gentle local cleaning: compatible soaking, a soft brush or controlled compressed air where suitable; avoid hard wire brushing and flows that distort the mesh.

PP and PTFE have different compatibility limits. Do not assume either a cleaning chemical or steam procedure is suitable from the plastic name alone.

When to stop reuse and replace

• Collapsed, crushed or permanently deformed mesh.
• Severe wire thinning, corrosion damage or failed welds.
• Broken support grids, detached joints or insecure fixing.
• Persistent abnormal pressure drop, carryover or drainage after compatible cleaning and inspection.
• Loss of structural integrity after prolonged thermal or corrosive service.

Investigate operating and installation causes as well as pad condition. Cleaning does not restore damaged mesh geometry or broken supports. Reuse depends on inspection; unlimited service life is not promised.

Manufacturing inspection

• Dimensions: outside/inside dimensions, pad thickness, segment sizes, mating clearances and assembled flatness.
• Mass and packing density: each mesh section weighed and density calculated from the agreed mesh volume; support-grid and frame mass accounted for separately.
• Wire and mesh construction: wire/filament dimensions, specified flat or corrugated structure and single-wire or multi-wire construction checked.
• Grids and joints: member dimensions, welds or plastic joints, missing connections and segment engagement checked.
• Segment assembly: identification, mating seams and fit to the specified support arrangement checked; large units divided to the agreed access dimensions.
• Materials: metal grade and MTC requirements verified; plastics checked against resin grade and supplier material documents.

These are manufacturing and conformity checks. They are not individual separation-efficiency, flooding or wet pressure-drop tests. Any additional performance verification requires an agreed method and acceptance criteria.

Custom demister pads and replacement units

New project

Send the operating conditions and vessel layout. We can discuss manufacturable mesh, support and segment options for customer review. Final process design and selection are confirmed by the customer.

Manufacture to drawing

Provide the approved mesh style, density, material, pad thickness, segment drawing, supports, fixing details and inspection requirements.

Replace an existing demister pad

Send the nameplate, existing style, drawings, photos or sample. Used parts may be deformed or fouled. Confirm recovered dimensions and construction before production; a brand/style cross-reference alone does not guarantee equivalent performance.

Demister pad FAQ

Is separation efficiency tested on every pad?

No. Published project efficiency is a design estimate or agreed target. Factory checks focus on the specified construction, dimensions, mass/density, materials and assembly.

Does higher mesh density always improve separation?

No. Density must be considered with wire size, thickness, gas/liquid loading and drainage. A denser pad is not automatically the correct choice.

Can you supply segmented mesh mist eliminators?

Yes. Round, ring-shaped and rectangular pads can be supplied as segments to drawing, with grids, frames and fixing accessories where specified.

Can a pad be used with horizontal gas flow?

Yes. We manufacture to the agreed flow direction, support arrangement and drainage design. Confirm orientation before ordering.

Can plastic demister pads be steam-cleaned?

Only where the complete assembly and cleaning temperature have been confirmed suitable. PP, PE, HDPE and PTFE must not be treated as interchangeable materials.

How does this differ from other knitted mesh products?

This page covers layered vessel/tower pads for liquid-droplet separation. See knitted mesh rolls for base material, compressed knitted filters for die-formed parts and knitted panel filters for framed panels.

Information for a demister pad inquiry

• Flow: minimum, normal and maximum gas flow; identify actual or standard m³/h and the reference conditions.
• Operating conditions: temperature and pressure at the pad.
• Gas/liquid properties: gas density and viscosity; liquid density, surface tension, composition and corrosion conditions.
• Liquid loading: entrained liquid quantity with units and reference basis.
• Separation target: droplet-size distribution where available, target sizes and required collection efficiency/test basis.
• Pressure loss: allowable operating pressure drop and any structural differential-pressure requirement.
• Vessel and pad: vessel inside diameter, effective flow area, pad thickness and available installation height.
• Access: manhole dimensions, segment handling and transport limits.
• Installation: gas direction, drainage, support beams/seats, grid and fixing drawings.
• Service: fouling, scaling, cleaning requirements and replacement history.
• Replacement references: current style/nameplate, drawings, photographs or sample.
• Order: quantity, material documents, tolerances and inspection/acceptance requirements.