PTFE Sliding Supports

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General Information

In a wide range of applications, PTFE Slide Bearings are superior to conventional expansion plates, rollers and rocker arm type supports. They support petrochemical plant, heavy machinery, pipelines, buildings and bridge girders; they accommodate expansion, contraction and other reciprocating motions of any structure that moves as a result of therma,. Seismic or differential forces.

Bearings for such applications must operate at high loads and low speeds, and it is under just these conditions that the self-lubricating properties of PTFE are at maximum. This factor, together with its no stick-slip and anti-weathering characteristics, is the principle reason why PTFE has proved to be so successful as a slide bearing material.

Advantages

• The simplicity of the bearing design and its ease of fabrication and installation make the unit cost efficient
• The costs of a construction can be reduced by designing for expansion rather than strain
• Coefficient of friction over the bearing surface remains constant, even under worst case conditions
• The bearings are maintenance free – PTFE is inherently self – lubricating, while dirt particles are absorbed into the material. Only simple protection is required against the significant ingress of dirt

Design / Selection

Carpenter & Paterson offers a specialist service, based on many years experience in the use of PTFE and its application to slide bearings to assist in the design of bearing systems.

Low friction sliders with coefficient of friction less than 0.1 are available. They are designed specifically for the loads and movements required. Most assemblies are also designed to be compatible with our range of standard sliders and glides, such as Fig 381, Fig 382, Fig 384 etc as illustrated on page 165.

Also 'stand alone' Slide Bearing Sandwich Plates Fig No SLB 90 are available – as shown in our Pipe Support Manual

Bearing Assemblies

Carpenter & Paterson Slide Bearings consist of a single PTFE pad counter faced with a polished stainless steel plate. The assembly is designed to ensure that the PTFE pad is covered by the S/S plate throughout the expected design movements.

The basic element is a 5mm PTFE sheet, recessed into a 10 mm steel backing plate for straight forward field installation by welding or bolting. The corresponding 3mm thick polished stainless steel plate is shop fitted to a 6mm thick carbon steel plate. Alternative thicknesses and materials for the backing plates can be supplied.

Where operating conditions require them, thermal insulation and vibration damping pads may be bonded between the PTFE sheet and the backing plate, or between the backing plate and the structure. To allow operation at high ambient temperature, a high temperature epoxy resin system is used for bonding, and the adhesives are cured under strictly controlled conditions, ensuring that the bond is stronger than the PTFE itself.

As standard glass filled PTFE is used as the bearing material, the load bearing capacity is 140 Kg / Cm²