The Parker Prädifa OV flange seal made of polyurethane compounds was developed as an alternative to conventionally used O-ring/back-up ring combinations for static sealing at high pressures. The robust seal geometry and use of particularly extrusion-resistant Parker polyurethane compounds simplifies installation and enhances sealing performance in pulsating pressure conditions, resulting in significantly longer service life. The OV flange seal is particularly suitable for SAE flanges and inferior surface qualities of the flange components. Due to the interference fit, the geometric design of the flange seal prevents the otherwise frequent occurrence of O-ring “pumping.”

Leakage which has been observed when O-rings are used can be attributed to a pressure buildup on the outer diameter which occurs with pressure surges and pressure fluctuations, frequently causing O-rings to be pulled out of their seats and being carried off by the fluid flow. This profile and the recommended groove prevent this effect. A radial movement and the wear it entails, which may occur with O-rings, is avoided by the special shape of the OV seal.

• Enhanced sealing performance in non-pressurized
• Insensitive to pressure
• Seal geometry prevents pressure build-up on the low-pressure side in case of pressure
• High extrusion resistance.
• Excellent media resistance in case of suitable compound
• Suitable compounds available for special requirements of the chemical process industry.
• Suitable compounds available for special requirements of the food processing
• Installation in closed and undercut
• Interference fit on the outer diameter enables overhead installation.
• Additional sizes of machined products available on short

Range of application

Static seal for SAE flanges.

Operating pressure                                          ≤ 600 bar

Operating temperature                                    -35 °C to +100 °C

Compounds

Ultrathan® P5008 is a polyurethane-based Parker Praedifa compound with a hardness of approx. 93 Shore A. In comparison with other polyurethane materials currently available on the market it excels because of its increased heat resistance, improved performance against hydrolysis, and low compression set values.

Installation

The installation groove at the back of the sealing element must be ventilated. The peak-to-valley height of the seal orientated plate surface must be Rt ≤ 6.3 µm, whereas the plate with the countersink must have a peak-to-valley height of Rt  = 2030 µm,

e.g. obtained by milling according to DIN 3142 B5P4. If there are several passages

bores, additional ventilation channels can be provided between the oil supply bores.