Hydraulic Sealing Products

Lofilm® HD - for rams, rods & glands

Lofilm® HD is a pressure responsive hydraulic seal specifically designed for arduous reciprocating gland applications, where fast pressure rises occur and side loads can be substantial. In heavy-duty horizontal applications, it operates as a highly efficient seal and also accommodates lateral or side loads. 

The seal normally comprises one heavy-duty intermediate ring of rubberised fabric, a gland ring/female adapter, and a moulded rubber asymmetrical header ring that is the principal sealing element of the set. 

An annular groove incorporated in the header increases its response to applied pressure. The ported 'odd-leg' header design allows gland loading to be transferred through the set to the neck bush - often not fixed - while enabling the system pressure to act on the annular groove. In addition, the rubber sealing lips conform readily to an uneven surface - such as a worn shaft - to improve sealing integrity.

In operation, the initial radial interference reduces the fluid film to a minimum over a wide range of conditions, particularly on down-stroking where excessive leakage can be hazardous. This is also important on equipment that uses auxiliary cylinders to provide rapid advance. 

Special features

  • Robust, high integrity seal, well proven on heavy duty ram applications.. 
  • Pressure responsive primary sealing ring provides instant sealing action, even at low pressure.
  • Improved sealing integrity on worn shafts to extend ram operating life.
  • Available in split form for major downtime savings. 
  • Can be supplied with Self-aligning Gland Ring.

Typical applications
Arduous duties with rams on forging and extrusion presses, including heavy duty horizontal applications. Also, equipment with rapid advance mechanisms, where Lofilm® HD can prevent air being drawn into the system: this avoids uncontrollable movement of the main ram and possible severe damage to the seal and other components by cavitation.

Operating capabilities

  • Maximum operating pressure: 62MPa (8992psi).
  • Temperature range (standard materials): -20°C to +120°C (-4°F to +248°F).
  • Maximum surface speed: 0.5m/s (98.4fpm) For higher speeds please consult our Technical Support Team.

Materials of construction
Gland ring/female adapter
Standard material:
heavy duty cotton fabric proofed with medium nitrile (NBR) rubber. 
Special materials: heavy duty synthetic fabric proofed with hydrogenated nitrile (HNBR), butyl (IIR), or fluorocarbon (FKM).

Intermediate ring
Standard and special materials:
as for gland ring.

Header ring
Standard material:
nitrile NBR rubber.
Special materials: hydrogenated nitrile (HNBR), butyl (IIR), or fluorocarbon (FKM).

Media capabilities
Standard materials - ie, nitrile (NBR) - are suitable for use with most mineral based hydraulic fluids, and most fire-resistant fluids of the water/oil emulsion or water/glycol types at temperatures up to 120°C (248°F).They also resist air, water and most lubricating oils and greases.

Special materials extend considerably extend the range of applications in terms of temperature, fluid compatibility and abrasion resistance. Please consult our Technical Support Team. 

How supplied
Endless or split packing sets to fit standard housings of 540mm to 1935mm OD, or 20.5 inch to 76.125 inch OD. We also hold a substantial library of mould tools for non-standard sizes. Other sizes are manufactured to order, but tooling charges may be incurred. Fitting instructions are supplied with every seal.

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