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A sliding support carries the pipe while allowing defined relative movement, for example due to thermal expansion.
The sliding support is the simplest and most common pipe support: the line rests on a beam and can move horizontally on it. It carries the weight downwards and restrains nothing else – neither axial nor lateral movement, nor lift-off.
Usually it is not the pipe itself that rests on the beam but a pipe shoe. It protects the pipe wall from wear, keeps the insulation clear of the beam and provides a flat sliding surface.
The movement is only nearly free. Sliding produces a friction force of friction coefficient times support load, acting against the movement. It loads the beam horizontally and is passed along the line to the next anchor.
For steel on steel a friction coefficient of around 0.3 is commonly assumed, for PTFE against polished stainless steel about 0.1. These are design assumptions; the project specification and the slide plate manufacturer’s data govern. A support carrying 10 kN therefore transmits roughly 3 kN of horizontal force with steel on steel – at every support along the run.
On a long pipe rack the friction forces of many supports add up to a considerable anchor force. Close to pumps and turbines the friction of a single support can already use up the allowable nozzle load. In both cases slide plates with a low friction coefficient are an effective and simple remedy.
Their limits of use – temperature, bearing pressure, contamination – are stated by the manufacturer. A dirty or corroded sliding surface no longer has the friction coefficient used in the calculation.
A sliding support carries only as long as the pipe rests on it. If thermal expansion lifts the line in operation, the support is ineffective and its share of the load shifts to its neighbours or to the nearest connection. The stress analysis reveals such locations; instead of a sliding support they need a support that follows the movement – a spring hanger or a base-mounted spring.
Sliding supports are simple – and are therefore often placed rather than designed.
What Entracon offers here is on the matching page.
See what we offer| Sliding pair | Friction coefficient (assumption) | Use |
|---|---|---|
| Steel on steel | around 0.3 | Standard case |
| PTFE on polished stainless steel | about 0.1 | Near sensitive connections, long pipe racks |
| Roller support | considerably lower, per manufacturer | Large loads and travel in one direction |
The sliding support only carries and permits any horizontal movement. The guide additionally restrains movement across the pipe axis. Many guides are, in construction, sliding supports with lateral stops.
Long enough to stay safely on the beam in every operating and upset condition: beam width plus the largest movement in both directions plus a margin. The movements come from the stress analysis.
For anchors and connections, yes, because it generates additional forces. But it also stabilises: friction damps small movements and vibration. It should not be relied on, though, because its magnitude varies widely.
One short conversation usually settles more than three quotations. Call or write — you will reach an engineer directly.
Start typing – for example “balancer”, “SAP” or “pipe stress”.
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