O-RING Moulded 135 FKM GP Pk1

Nitrile ‘O’ rings

Our nitrile (VOR) ‘O’ rings are manufactured from butadiene/acrylonitrile. Commonly referred to as nitrile rubber.


Fluoroelastomer ‘O’ rings

Our fluoroelastomer (VIT) ‘O’ rings are manufactured from a copolymer of vinylidene fluoride and hexafluoro-propylene. Fluoroelastomer ‘O’ rings should be used in systems operated below 10^-6 mbar.

Fluoroelastomer ‘O’ rings take up a set as their operating temperature increases, but this does not affect their sealing properties in vacuum applications.  A fluoroelastomer ‘O’ ring will restore to its normal shape after uncompressed exposure to atmosphere:  accelerate this process by heating to 150 °C in air. The baking temperature of fluoroelastomer need not exceed 150 °C, since a higher temperature will not, after cooling; further reduce the outgassing rate of the fluoroelastomer.

For convenience, we give fluoroelastomer ‘O’ rings the same size reference figure group as corresponding nitrile ‘O’ rings, but although the two materials are moulded to the same nominal sizes, fluoroelastomer ‘O’ rings have wider tolerances than those specified in BS1806.

Nitrile ‘O’ rings

    Low outgassing rate
    Good deformation resistance (very resistant to set after compression)
    High resistance to most oils.

Fluoroelastomer ‘O’ rings

    Very low outgassing rate (especially after baking)
    Chemical stability at high temperatures up to 200 °C
    High resistance to oils and many chemicals.

The most useful characteristics of Nitrile 'O' rings for vacuum use are:

• Low outgassing rate
• Good deformation resistance (very resistant to set after compression)
• High resistance to most oils.

Fluoroelastomer offers:

• Very low outgassing rate (especially after baking)
• Chemical stability at high temperatures up to 200 °C
• High resistance to oils and many chemicals.

Physical data
Operating pressure range (absolute)
C clamp and centring ring	10-7 mbar - 1 bar
Stainless steel clamping ring and Co-seal	10-7 mbar - 17 bar
Stainless steel clamp and metal seal	10-8 mbar - 3 bar
Stainless steel clamp and Co-seal (all sizes)	10-7 mbar - 17 bar
Polymer and aluminium clamps and Co-seal
NW10 to NW25	10-7 mbar - 17 bar
NW40 to NW50	10-7 mbar - 10 bar
NW trapped ‘O’ ring	10-7 mbar - 10 bar
‘O’ ring and centring ring (vacuum use only)	10-7 mbar - 1 bar
Bellows	10-7 mbar - 1 bar
Flexible pipelines	10-7 mbar - 2 bar
Braided flexible pipelines*	10-7 mbar - 10 bar
*  Depends on size
Operating temperature
Polymer Co-seal	-10 to 80 ºC
Aluminium Co-seal and nitrile seal	-10 to 100 ºC
Aluminium Co-seal and fluoroelastomer seal	-10 to 200 ºC
Polymer centring ring and nitrile ‘O’ ring	-10 to 100 ºC
Polymer centring ring and fluoroelastomer seal	-10 to 125 ºC
Nitrile ‘O’ ring	-10 to 100 ºC
Fluoroelastomer ‘O’ ring	-10 to 200 ºC
Polymer clamp
Constant vacuum use	-10 to 100 ºC
Intermittent vacuum use	-10 to 125 ºC
Stainless steel clamping ring	-10 to 125 ºC
Aluminium clamping ring	-10 to 200 ºC
Stainless steel clamp	-10 to 200 ºC
Standards compliance
NW and ISO fittings	Pneurop 6606 (1981),
	ISO1609 (1986)
	DIN28403, DIN28404
CF fittings	ISO3669
Stainless steel equivalents

AISI number	German steel number	DIN standard
304	1.4301	X5 CrNi 18 10
303	1.4305	X10 CrNi 5 18 9
304L	1.4306	X2 CrNi 19 10
301	1.4310	X12 CrNi 17 7
316	1.4401	X5 CrNiMo 18 10
316L	1.4404	X2 CrNiMo 17 13 2
316Ti	1.4571	X6 CrNiMoTi 17 12 2
321	1.4541	X10 CrNiTi 18 9

'O' Ring (pack of 10) sizes – see Dimensional drawing

		A	B
Nitrile
NW10		15	5
NW16		18	5
NW25		28	5
NW40		42	5
NW50		50	5

Chemical resistance
This information is provided as a general guide only. Further guidance should be sought with respect to specific chemicals and their applications

MATERIAL	GENERALLY RESISTANT TO	GENERALLY ATTACKED BY
NITRILE
Butadiene Acrylonitrile copolymer	Many hydrocarbons fats, oils greases, hydraulic fluids	Ozone, ketones, esters, aldehydes, chlorinated and nit