Bag filters provide a wide means to remove solids from liquids within a plant. A filter bag sits inside a housing, and a stream of liquid with solids in it flows through the bag. This bag filter captures the solids, and a clean stream continues.

The majority of the plants out there run on standard bags. There are multiple good reasons for this: You can find standard-sized and micron-rated bags to fit any industrial task you can think of.

But not every process fits the standard range. Some plants have older housings in odd dimensions. Some run liquids too hot or too aggressive for standard media. In those situations, a standard bag is a compromise, and that invariably shows up as leaks, bag life problems, or solids ending up in your process equipment that were meant to be kept clean.

When a standard bag stops working

Standard filter bags can do the work in many situations: standard sizes housing, standard micron sizes, standard fluids, etc. They are the best possible solutions for many industrial applications, and there is no need to look further. 

The trouble starts when a process sits outside those common conditions. An older housing with a non-standard diameter. A hotter liquid beyond the handling capacity of Polypropylene. A micron requirement that falls between the standard steps, so the nearest stock option is either too coarse to protect the equipment or too fine to last even a week. 

Custom bag filters remove the need for compromise. Instead of adjusting the process to accommodate the bag, the bag is built around the process.

Types of custom bag filters

A custom size doesn’t have to be complex, and in most cases it only involves one or two modifications of an existing standard bag so that it serves its purpose accurately.

Custom sizes: Bags made to a specific length, diameter, or ring type so they seal correctly in a non-standard housing.

Fully welded bags: No stitch holes, so there is no route for unfiltered liquid to slip through. Used where pressure is high or hygiene matters.

High-capacity bags: Extra filtration area, so the bag holds more before it needs changing.

Food and pharmaceutical grade: Compliant, traceable media for processes that have to meet regulatory requirements.

Special media bags: Polyester for hot or oily liquids, nylon for abrasive duties, PTFE for aggressive chemicals.

They can also be combined. A food plant might have an older housing which requires a bag which has been fully welded in a way that complies and made to a size nobody has readily available. Custom filter bags have been developed for exactly that sort of requirement.

Benefits of going custom

Most importantly, nothing within the system is left to guesswork. A bag fitted for the housing creates a perfect seal, eliminating any chance of unfiltered liquid bypassing. A micron rate that matches what is needed provides process clarity rather than a nearest approximation. Media chosen for the real temperature and chemistry lasts as long as it should rather than breaking down early. 

But there’s a cost advantage, even if it’s sometimes overlooked. While a custom bag might have a higher per-bag cost, because it carries more, lives longer, and has fewer failures, the number of change-outs decreases. Additionally, a custom bag protects more expensive components-pumps, heat exchangers, membranes. In food and pharma work, avoiding a single rejected batch can cover a long run of custom bags on its own. 

Where custom bag filters are used

Industrial filter bags are found in virtually every process industry, with custom designs appearing wherever the standard range doesn’t quite suffice.

They work in water treatment for suspended solids where a stock bag housing or flow rate is unlikely. Chemical and paint applications demand a filter that doesn’t fall apart due to acids, paints, or solvents. Food and beverage applications call for a compliant, traceable solution that fits their syrup, oil, dairy, or process water applications.

Pharmaceutical companies need certified media with secure seals.

Oil and gas, textile, and power generation are just a few more industries utilizing the versatile power of the Industrial Bag Filter in applications for lubricants, dyes, and cooling water.

This is a classic pattern. The industry defines the criteria of the terms, and the criteria determine what the bag must be like.

Choosing the right supplier

A custom bag is only as great as the supplier who makes it. Custom Industrial Filter Bags need manufacturing, not just someone who places the order.

Look for a Filter bag manufacturer that produces in-house, tests bags before dispatch, and can adjust micron, media, size, and seam to a specific requirement. A capable Filter bag supplier should also be able to repeat that exact specification on future orders, because a custom bag is only useful if the second batch matches the first. 

MMP Filtration manufactures across the range of liquid and dust bag filter solutions, including custom sizes and specifications for industrial buyers.

Conclusion

Custom bag filters are often treated as a last option, something to try after standard bags have failed a few times. 

The cheapest point to solve a filtration problem is before the first order is placed, when the housing can be measured properly, the fluid tested, and the micron rating set against what the process actually needs. 

Delaying the bag replacement until bags begin failing results in paying for the problem twice – for your failed bags and for the damage done by the bypassed contaminants to your downstream equipment. Custom bag replacements early are never expensive; it is simply an accurate one.