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Back-up ring - BUU

Application Material Profile Standard Hardness
Shore A
Pressure - (max) bar Temperature Sliding Speed
(max m/sec)
Dimension Price Pressure
Back-up ring - BUU TPC-ET -40°C+120°C

TPC-ET (Thermoplastic polyester elastomers) is a material which consists of both thermoplastic and elastomeric properties. This compound is also known under the trade name Hytrel ®*.
Back-up rings BUU are primarily used in combination with O-rings to support the O-rings from extrusion. The back-up ring BUU reduces the gap and prevents the O-ring from being pushed into the gap and damaged. Back-up type BUU is designed with a profile which helps keep the O-ring in place in critical applications at high pressures. 

Profile BUU Back-up ring

Profile BUU back-up ring.

• Can be used both for static and dynamic applications
• Used for rod and piston
• Functions in tough conditions
• Functions at high pressure
• Resistance to heat (+120°C)
• Resistance to cold (-40°C)
• Wide range of dimensions
• Easy installation and removal

Used in almost every industry but especially in non-moving machinery and in static sealing applications.
All types of hydraulic cylinders, injection moulding machines, mining equipment, marine hydraulics, loading platforms, cranes and heavy duty applications.

BUU back-up rings can only be compressed or stretched to a very limited extent during the installation, to avoid deforming the back-up. Easily assembled into the housing by hand. The back-up ring is in non-split form. If installation is difficult, the back-up ring can be cut carefully at a 30°- 45° angle and assembled afterwards. It is very important that the assembly tools must be of soft material and have no sharp edges.

For applications where the pressure changes from side to side, a back-up ring should be mounted on both sides of the O-ring. For special applications BUU back-up rings can be produced in PTFE.

For further information about back-up rings, please call us.

*Hytrel® is a registered trade mark of DuPont Performance Elastomers.