Aftermarket replacements for selected Flygt Plug-In seal applications

The Luwint LT series provides integrated double cartridge mechanical seals for selected Flygt pumps and mixers. Each assembly combines two sealing interfaces in one unit, offering a replacement option for equipment originally fitted with a compatible Flygt Plug-In seal.

The range includes 20, 25, 35, 45, 60 and 80 mm shaft sizes. Selection depends on the complete equipment designation, original seal reference and installation dimensions—not shaft diameter alone.

Why Choose the LT Series

• Integrated double-seal assembly: combines the inner and outer sealing functions in one cartridge.

• Six shaft-size options: covers the configurations listed in the replacement catalogue.

• Specified face combinations: Tungsten Carbide face pairs across most sizes, with a Ceramic component listed for LT20.

• Identification assistance: match the original seal, equipment version and material requirements before ordering.

Understanding the Plug-In Arrangement

Flygt’s original Plug-In concept incorporates independent inner and outer seals within a single assembly. The outer seal separates the pumped medium from the seal-fluid chamber, while the inner seal separates that chamber from the motor-side space.

The LT series is supplied as an aftermarket replacement for selected installations using this arrangement. It should not be confused with separate upper and lower seal assemblies, such as those used in Griploc configurations.

Where the original seal incorporates a cooling or circulation feature, confirm that the proposed replacement matches the equipment’s requirements.

Catalogue Application References

Luwint model	Shaft size	Listed Flygt application references
LT20	20 mm	2610, 2620, 2630, 2640, 4610, 4620
LT25	25 mm	2660, 4630, 4640
LT35	35 mm	2670, 3153, 5100.211, 2100.211
LT45	45 mm	3171, 4650, 4660, 5100.250, 5100.251, 5100.260, 5100.261
LT60	60 mm	3202, 4670, 4680, 5100.300, 5100.310, 5151.300, 5150.310
LT80	80 mm	3301, 5150.350

These references follow the supplied replacement catalogue and require confirmation against the actual equipment version. Model suffixes, drive-unit details and original seal part numbers can be important to selection.

Materials

Model	Catalogue material designation
LT20	TC / TC / TC / Ceramic / Viton
LT25, LT35, LT45, LT60, LT80	TC / TC / TC / TC / Viton

TC denotes Tungsten Carbide. Viton denotes the listed FKM elastomer.

The LT20 designation includes both Tungsten Carbide and Ceramic. Confirm the face pairing at each sealing position when ordering, as the supplied sheet does not explicitly assign the material sequence to the inner and outer seals.

Exact carbide and elastomer grades should be checked for the liquid and seal-chamber fluid. Pressure, temperature and speed limits must be confirmed for the selected replacement assembly.

Applications in Australia

Subject to verified compatibility, LT-series replacements can be considered for maintenance of equipment used in:

• Sewage and wastewater pumping

• Construction and industrial dewatering

• Stormwater and drainage systems

• Wastewater mixing and treatment

• Industrial water management

Provide details of abrasive particles, chemicals or elevated temperatures so the material selection can be assessed.

Sydney Supply. Detailed Catalogue Available.

Contact Luwint for the full Flygt replacement mechanical seal catalogue, including additional configurations and identification information.

Send the equipment nameplate, original seal part number, shaft size and clear photographs of the old cartridge. Include its key dimensions, operating conditions and any internal cooling-system details.

We can help identify the required assembly and confirm current availability, pricing and dispatch timing.

Contact: Wayne Liao
Email: wayne@luwintonline.com
Mobile: 0433 986 633

LUWINT is an independent aftermarket supplier and is not affiliated with or endorsed by Flygt or Xylem. Flygt and Plug-In names are used solely for identification and cross-reference.