Introduction If you operate TL300, VALMET or VOITH/Sulzer pressure screens and are searching for reliable alternatives to John Crane’s Safematic/SAF and SE2 series, FBU Seals offers engineered drop-in solutions. Our 2650 and 2850 double-balanced cartridge seals are designed for heavy-duty screening and pulp/paper applications where solids, abrasives and contaminated liquids are present. 

This page helps OEMs, MRO teams and plant engineers comparing options and choosing compatible, high-performance seals.

Why choose a qualified alternative Many operations seek compatible mechanical seals that meet OEM performance while offering straightforward installation, proven durability and cost-effective lifecycle performance. Rather than replacing system hardware, a well-matched alternative seal should:

• Fit typical shaft diameters and cartridge spaces used by TL300, VALMET and VOITH MS series screens

• Match pressure, temperature and sliding-speed limits

• Support standard piping plans for barrier/flushing control (e.g., plan 54/GLD)

• Deliver easy installation, low maintenance and long service life

Quick product match summary 

• For TL300 and VALMET pressure screens: FBU 2650 Double Cartridge Seal — recommended as a compatible alternative to John Crane SAF (Safematic) series.

• For VOITH SULZER / MS series pressure screens: FBU 2850 Double Seal — recommended as a compatible alternative to John Crane SE2 (SE2C) series.

2650 — Compatible alternative to John Crane SAF (Safematic / SAF)

Core design & target applications

• Double-acting, double-balanced cartridge seal engineered for heavy-duty pumps, screens, knotters and pulpers handling liquids with solids and impurities.

• Intended for TL300, VALMET and similar pressure screens and heavy process equipment.

Key technical highlights

• Double-balanced construction: independent of pressure changes in both process and barrier fluid.

• Double seal with multi-spring structure and sliding O-ring for larger axial displacement.

• Larger buffer chamber flushing space, bidirectional flow for enhanced cooling.

• Recommended piping plan: GLD (plan 54) or other between-seal piping (52, 53 variants) as appropriate.

• Typical size range covered: 30 mm to 200 mm shaft diameters.

• Performance: seal chamber pressure ≤ 20 bar; buffer chamber water pressure ≤ 15 bar; temperature -20 °C to +180 °C; sliding velocity ≤ 20 m/s.

• Materials: 316SS, Duplex, Titanium, other alloys. Suitable media: water, oils, solvents, pulp slurries.

Benefits vs. SAF

• Equivalent double-balanced, cartridge-style robustness and pressure-independence.

• Designed for heavy solids-laden services with easy installation and low maintenance.

• Supplied to fit common OEM equipment used across pulp & paper and screening lines.

2850 — Compatible alternative to John Crane SE2 (SE2C)

Core design & target applications

• Double-acting, double-balanced dual cartridge seal tailored for VOITH MS series pressure screens and Sulzer-style process pumps in abrasive slurry services.

Key technical highlights

• Two multi-spring sets (inner and outer) for stable spring loads across both seal pairs.

• Larger buffer chamber flushing space, bidirectional flow for cooling.

• Compatible with GLD (plan 54) and other between-seal piping plans (52, 53 variants).

• Shaft diameters commonly covered: 70 mm, 94 mm, 101 mm and similar VOITH MS sizes.

• Performance: seal chamber pressure ≤ 20 bar; buffer chamber water pressure ≤ 15 bar; temperature -20 °C to +180 °C; sliding velocity ≤ 20 m/s.

• Materials and media: same options as 2650.

Benefits vs. SE2

• Matches the SE2’s dual-balanced cartridge concept optimized for slurry, pulp and harsh process fluids.

• Designed for VOITH MS form-fit compatibility and reliable long-term operation.

Compatibility & installation notes

• FBU 2650 and 2850 are engineered to align with common OEM interfaces used by VALMET, VOITH, Sulzer and similar brands. Final compatibility requires verification of shaft diameter, sleeve dimensions, gland/cover geometry and piping-plan connections.

• We recommend providing dimensional drawings or seal chamber measurements for confirmation and offering retrofit kits or adapter components if small modifications are needed.

• Recommended piping plan for barrier/flushing: GLD (Plan 54) or equivalent between-seal plans (52, 53A/B/C) per application requirements.

Reliability, materials & service

• Materials: corrosion- and abrasion-resistant alloys available (316SS, Duplex, Titanium, special alloys) and suitable sealing faces and secondary elastomers for pulp and chemical environments.

• Designed for reduced failure risk, easier servicing and low maintenance costs — suited to continuous heavy-duty screening operations.

Call to action 

Contact FBU Seals’ technical team with your John Crane model number, pump/screen type, shaft diameter and seal chamber dimensions. We’ll confirm fitment, provide a quotation and recommend the optimal piping plan and materials for your service.

FAQ

1: Are the 2650 and 2850 direct drop-in replacements for John Crane SAF/SE2 units? 

In many cases they are compatible; however, confirmation requires verification of shaft diameter, gland dimensions and seal chamber geometry. We can confirm fit with drawings or photos.

2: Do these seals support the same pressure and temperature ranges as John Crane’s SAF/SE2? 

Yes — both FBU models are double-balanced and rated for similar service envelopes: up to 20 bar seal chamber pressure and -20 °C to +180 °C, depending on materials and faces.

3: Which piping plan should I use for barrier water control?

GLD (Plan 54) is recommended for best control; between-seal plans (52, 53 variants) are also applicable depending on your system and application.

4: What materials are available for abrasive/slurry services?

Options include 316SS, Duplex stainless, Titanium and other specialty alloys, plus appropriate face materials and secondary elastomers chosen for your media.

5: How do I proceed to get a replacement seal?

Send your OEM seal model, shaft diameter and seal chamber drawing or photo to our sales/technical team. We’ll validate compatibility, suggest the correct model (2650 or 2850), and provide lead times and pricing.