Industrial Bag Filter Skid: A Practical Guide

Bag filters can ship as single housings or as complete skid-mounted units. For an industrial project, the real question is how the filtration has to fit into your process, and how much of it you want assembled before it arrives on site.

An industrial bag filter skid integrates the whole filtration system onto one structural frame. The arrangement is built around your application, not around a catalogue page.

The bag filter housing sits at the center of that package. Get the housing right and the rest of the skid falls into place. Get it wrong and you are rebuilding piping on site.

What a Bag Filter Housing Does

A bag filter housing is a pressure-rated vessel that holds the filter bag and keeps liquid flowing through it under control. The housing does three jobs.

• It supports the bag so the bag cannot collapse under flow.
• It seals the fluid path so nothing bypasses the media.
• It holds system pressure and protects operators during changeout.

The housing is the permanent asset. The filter bag is the consumable. That is why housing material, size, and seal design matter more than the purchase price. A thin-shell housing with a rough seal face leaks early, and every leak costs product and downtime.

What Is Included in a Bag Filter Skid System

A bag filter skid brings filtration equipment and support components together on one frame. A typical system includes the following.

Single Bag vs Multi Bag Housing

The first housing decision is bag count. A single-bag housing is simple and cheap. It suits low flow and batch work. A multi-bag housing spreads the load across several bags and keeps the pressure drop low at high flow.

Match the bag count to your flow rate before you size the housing. Oversize the housing and you waste space and money. Undersize it and the pressure drop climbs until the bag blinds off.

Skid Configurations for Different Process Requirements

How the housings connect changes both capacity and maintenance flexibility. Three arrangements cover most industrial needs.

Parallel Bag Filtration

Two or more housings run on separate flow paths. Incoming liquid splits between them. The skid handles a higher total flow than a single housing can on its own.

Use parallel when flow is high or when solids load needs to spread across several bags. Actual capacity depends on flow distribution, bag loading, and pressure loss through the whole loop.

Duplex Bag Filtration

A duplex bag system uses two housings and a valve arrangement that switches flow between them. One housing stays in service while the other is isolated for a bag change.

This setup matters when a filtration stop would halt production. The catch is that the active housing must carry the full flow and solids load on its own during the switch. Valve placement and the changeover procedure have to fit how you actually run the line.

Multi-Stage Bag Filtration

Some processes need successive stages to hit a target liquid quality or protect downstream equipment. A coarse upstream bag takes the big particles first. A fine downstream bag polishes the rest.

Each stage needs its own filtration rating and flow capacity. Multi-stage earns its cost when different particle sizes have to be removed in sequence. It adds pressure loss and cost when a single stage would do the job.

Housing Material. Stainless Steel 304 vs 316L

Material choice sets service life and fluid cleanliness. For most industrial skids the decision is between 304 and 316L stainless steel.

Add molybdenum and you get a housing that resists chlorides and saltwater. If your stream can ever see chlorides, spec 316L. The upfront delta is small next to the cost of a corroded shell and a shut-down line. For food and pharma, add a polished internal surface so residue cannot hang up and bacteria cannot attach.

Sizing the Skid. Pressure, Temperature, Flow, and Micron Rating

Four numbers drive selection. Get them right and the skid runs predictably.

Pressure Design pressure should sit above maximum operating pressure, usually with a safety factor around 1.5. Standard bag filter housings often carry a 0.6 MPa design pressure. Exceed that and you need a high-pressure version.

Temperature. Temperature drives the seal material. NBR handles about 80°C. FKM reaches about 150°C. PTFE goes higher. Pick NBR for a hot stream and the seal hardens and leaks early.

Flow. Flow sets bag count and size. A No.1 bag moves roughly 20 m³/h of water. A No.2 bag moves about 40 m³/h. Higher flow means a multi-bag housing and larger connection ports to keep velocity down.

Micron rating. Match the rating to the real particle target. Finer ratings raise pressure drop and shorten bag life. Run a pilot test and pick the coarsest rating that still captures what you need. Over-filtering burns bags and energy.

Pre-Assembly, Testing, and On-Site Installation

The biggest advantage of a skid is that the main equipment and connections can be assembled and tested before delivery. Layout and interfaces get checked as a unit, in the factory, not on your floor.

Factory checks can cover component installation, piping connections, instrument fit-up, and pressure or leak testing, depending on the agreed scope. Set the test procedure and acceptance criteria up front for the specific system.

Pre-assembly cuts the component-by-component install work at your site, but expect to position and secure the skid, connect process piping and utilities, and finish commissioning checks.

Before it ships, confirm dimensions, weight, and lifting points, inlet and outlet locations, connection standards, the available installation space, and maintenance clearance. Nail these down and you avoid rework when the equipment arrives.

Bag Filter Skid Applications Across Industries

Industrial Process Water

Skids remove suspended solids from process water and circulating water to protect downstream equipment. Filter rating and housing capacity depend on water quality, solids loading, and what the next process stage needs.

Chemical Liquid Filtration

Chemicals demand careful material selection. Housing grade, filter media, seals, and pump wetted parts all have to match the chemistry, temperature, and pressure. Confirm compatibility during design, not after the first batch.

Paints, Coatings, and Resins

Viscosity and particulate content drive pump selection, pressure loss, and media choice. Give operators real access for bag changes, because retained material and product residue make servicing harder.

Data Center Liquid Cooling

Cooling loops need particulate control to protect cooling equipment and keep operation reliable. Bag filter skids can filter compatible coolant or support filtration during filling, flushing, and maintenance. Match housing material, bag rating, and flow capacity to the coolant properties.

Other Industrial Liquid Processes

Any liquid filtration duty that suits a packaged assembly can ride on a skid. Customize housing count, piping layout, pump spec, instrumentation, frame size, and process connections.

A Skid Built Around Your Process

One customer ran a coating line that could not stop. A single housing meant a full shutdown for every bag change. We built a duplex skid with a valve arrangement that let them switch over and swap bags while the line kept running. The changeover takes minutes, not a shutdown.

Planning starts with the process. The liquid to filter, the required flow, operating conditions, filtration rating, and available space. From there a single housing, a duplex arrangement, or multiple stages gets configured to fit.

BOLEFIL builds bag filter housings and the skids around them, sized and assembled for the application. Send us your process numbers and we will help you settle on a configuration that fits your line.

Contact BOLEFIL to talk through your bag filter skid requirements.