R+F FilterElements

Product Series

RF-SB Series — Spiral Link Belts

Spiral link drainage belts for belt press dewatering and gravity tables. Engineered for high drainage capacity, long service life, and consistent sludge cake quality — from municipal wastewater to industrial effluent.

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Spiral link belt for sludge dewatering showing interlocking polyester coils and filler wires

Series Overview

The RF-SB Series comprises spiral link belts constructed from interlocking helical coils joined by filler wires (cross-rods). This open-mesh architecture provides exceptional drainage capacity combined with high mechanical strength — making spiral belts the preferred choice for belt press dewatering of municipal and industrial sludge.

Unlike woven filter belts, spiral belts are virtually clog-free thanks to their three-dimensional open structure. They are easy to clean under high-pressure spray bars and maintain stable permeability over thousands of operating hours.

Clog-Free Design

3D open-mesh structure

High Drainage

15–45 % open area

Custom Dimensions

Up to 4,000 mm width

Filler Options

Round & flat cross-rods

Material Options

Spiral coils and filler wires are available in polyester and polyamide — each offering distinct advantages depending on the chemical environment and operating temperature.

PET (Polyester)

The standard choice for most belt press applications. Excellent hydrolysis resistance in acidic environments, high tensile strength, good dimensional stability. Temperature resistant up to 150 °C.

PA (Polyamide / Nylon)

Superior abrasion resistance for mineral slurries and heavy-duty dewatering. Excellent resistance to alkaline environments with good flexibility and fatigue resistance.

Belt Configurations

Standard Spiral Belt

Interlocking spiral coils connected by cross-rods (filler wires). The classic open-mesh belt for gravity and low-pressure dewatering zones.

Spiral Belt with Round Fillers

Round cross-section filler wires create a smooth surface for even sludge support and clean cake discharge.

Spiral Belt with Flat Fillers

Flat filler wires reduce open area for finer retention while maintaining high drainage capacity — ideal for biological sludge.

Key Design Parameters

Spiral Pitch & Open Area

Distance between adjacent spiral coils determines open area and retention. Fine pitch for biological sludge, wide pitch for high-volume drainage.

Wire Diameter & Strength

Spiral coil and filler wire gauge affect strength, flexibility, and belt weight. Heavier gauge for high-tension presses.

Edge Treatment & Seaming

Welded edges, reinforced selvedge, and guide strips ensure belt tracking. Clipper seam or endless construction available.

Technical Specifications

Approximate values. Actual specifications depend on belt configuration and application requirements.

MaterialMax. Temp.pH RangeOpen AreaWeightMax. Width
PET (Polyester)150 °C2–1015–45 %2.5–6.0 kg/m²4,000 mm
PA (Polyamide)120 °C3–1115–45 %2.5–5.5 kg/m²3,500 mm

Applications

Spiral link belts are the standard in sludge dewatering across a wide range of industries.

Municipal Wastewater
Industrial Effluent (ETP)
Paper & Pulp Mills
Food & Beverage
Mining & Minerals
Tannery & Textile
Chemical Processing
Oil & Grease Separation

Industries

Spiral belts are essential dewatering components in these sectors.

Need spiral belts for your press?

Share your press model, sludge type and belt dimensions — we will recommend the optimal spiral belt configuration.

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