How to Select Filter Press Cloth

Start with the Filtration Task

A cloth has to retain the target solids, release the cake and tolerate the actual slurry and cleaning routine. A cloth that gives clear filtrate in one service may blind quickly, leak at the edge or release poorly in another. Define the objective before choosing polypropylene, a weave or a finish.

• State whether the priority is solids retention, filtrate clarity, cake release, washing, throughput stability or a controlled change from the existing cloth.
• Record wet feed quantity and dry-solids information separately; do not describe either one as a guaranteed production rate.
• Describe the press and plate type, including recessed chamber, membrane or plate-and-frame construction.

Choose the Cloth Material and Construction

Material choice follows chemical contact, temperature, abrasion, flexibility and the cleaning method. Polypropylene is a common starting point for many industrial solid–liquid separation duties, but it is not an automatic answer for every slurry or temperature. The final material should be confirmed against the actual service and plate configuration.

Weave and surface are functional choices. A tighter surface may support fine-particle retention, while a more open structure may reduce resistance or help drainage; the correct balance must be checked against blinding and cake release. Monofilament, multifilament and mixed constructions can behave differently during cleaning and unloading. Ask for the cloth construction and nominal specification rather than relying on a generic “filter fabric” description.

• Material: confirm chemical compatibility, operating temperature and exposure duration.
• Construction: confirm weave, yarn type, surface treatment or finish when supplied.
• Opening and permeability: request the supplier's stated values and the test basis; do not convert them into a guaranteed press capacity.
• Cleaning: identify water washing, approved site procedure and any chemical exposure; never apply an unverified recipe to an unknown cloth or plate material.

Match the Cloth to the Plate and Installation

A suitable fabric can still fail when its geometry does not match the plate. Confirm the plate's length, width, thickness, chamber depth and feed or filtrate arrangement. Identify whether the cloth is one-piece, two-piece, draped, fixed with a neck, fitted with a center opening, or arranged with corner holes. Edge stitching, eyelets, snaps and retaining parts must correspond to the existing installation.

Use a Sample Confirmation Process

For an unfamiliar slurry or a proposed performance change, a sample and operating record are more useful than a broad product label. Send a representative original cloth section when available, plus a slurry sample or a clear description of solids behavior. State whether the sample was taken before or after conditioning, and identify the plate position from which it came.

• Photograph the nameplate and all cloth sides before removal.
• Label the original cloth, plate position and operating date.
• Provide slurry origin, solids description, temperature, pH if known, and any abrasive or sticky behavior.
• Record feed pressure separately from any squeeze pressure and from hydraulic-system pressure.

Distinguish Replacement from Improvement

A like-for-like replacement aims to restore the existing installation. The priority is dimensional and connection compatibility, with material and construction kept as close as the evidence permits. An improvement cloth changes one or more variables to address a documented issue. It should be treated as a controlled selection, not as a guaranteed upgrade.

Order Confirmation Checklist

Before quotation or production, send a single confirmation package. Shengqi can review the information with the replacement requirement, but the final cloth specification must be tied to the supplied evidence and approved application details. If a field is unknown, mark it as Not Sure rather than guessing.

• Filter press brand or model as shown on the nameplate, plus plate quantity and plate type.
• Cloth length, width, thickness or construction reference, and all relevant openings.
• Front, back, side, seal, handle, neck and stitching photographs with scale.
• Material, weave or original specification if available; otherwise send the sample.

Safe Installation and Follow-up

Installation and inspection must follow the press manufacturer's operating procedure. Stop the cycle, isolate relevant energy and confirm the press is depressurized before opening or removing cloths. Never open a press under pressure, perform electrical work while energized or bypass an interlock. Check plate alignment, cloth seating, openings and sealing surfaces before returning the press to service.