Replacing an industrial liquid filter bag is easier when the existing bag, process conditions, and filtration objective are documented before quotation. This guide explains the information U.S. maintenance, engineering, and purchasing teams should collect to identify a suitable replacement without relying on assumptions.
1. Confirm the Filter Bag Size
Start with the actual bag diameter and length, not only the housing model. Two common nominal configurations are:
- Size 1: approximately 7 inches in diameter by 16 inches long.
- Size 2: approximately 7 inches in diameter by 32 inches long.
These are common industry dimensions, but the existing bag and housing should still be measured. Also record the number of bags per housing and any dimensional tolerance or support-basket limitation.
2. Identify the Filter Media
The correct media depends on the liquid chemistry, temperature, filtration mechanism, and service conditions.
- Polypropylene felt: commonly considered for many chemical-processing, plating, water-treatment, and general industrial liquids where compatibility is confirmed.
- Polyester felt: a versatile depth-filtration option for many water-based and industrial fluids.
- Nylon monofilament mesh: a surface-filtration option for defined particle retention, solids recovery, or applications where a washable bag is preferred.
Chemical compatibility must be checked against the actual liquid, concentration, temperature, and exposure time. A material name alone is not enough to approve a bag for service.
3. Specify the Micron Rating and Filtration Goal
Provide the current micron rating and clarify whether the process requires nominal or absolute-rated performance. Standard felt and mesh liquid filter bags are commonly specified by nominal retention, while critical applications may require a different construction or a validated efficiency requirement. Also state whether the goal is equipment protection, product clarification, solids recovery, or final polishing.
4. Match the Ring or Flange Style
The bag opening must seal correctly in the existing housing. Record whether the current bag uses a steel snap ring, plastic ring, molded flange, drawstring, or another top construction. Photos of the bag opening, housing basket, and nameplate are often helpful. Do not assume two bags with the same diameter and length have interchangeable sealing systems.
5. Review Seam and Bottom Construction
Confirm whether the bag is sewn or welded, and whether the bottom is round, flat, or another design. Construction affects fit, bypass control, particle shedding, and compatibility with the application. If the process has cleanliness or fiber-release requirements, include them in the request.
6. Record the Operating Conditions
A reliable selection requires more than a part number. Provide:
- Liquid name and composition, including concentration and additives
- Normal and maximum operating temperature
- Flow rate and liquid viscosity
- Normal clean pressure drop and the bag-change limit
- Expected solids loading and particle characteristics
- Housing manufacturer, model, basket dimensions, and connection arrangement
- Required quantity, delivery location, and requested delivery date
7. When to Replace the Bag
Replacement is normally based on the approved differential-pressure limit, reduced flow, product-quality change, scheduled maintenance, or visible damage. The correct change-out point depends on the housing, pump, process, and operating procedure. Follow the equipment manufacturer’s limits and site safety requirements rather than using one universal pressure value.
Information to Send for a Quotation
For a faster review, send the bag size, media, micron rating, ring or flange style, seam and bottom construction, liquid and temperature, flow rate, housing details, quantity, and delivery ZIP code. If the existing specification is uncertain, include clear photos and any current label or part number.
Browse FiltEdge US liquid filter bags, compare PP liquid filter bags, polyester liquid filter bags, and nylon mesh liquid filter bags, or contact our team for selection support and a quotation.
Selection guidance is application-dependent. Final suitability should be confirmed using the actual process conditions and required filtration performance.