BECA 519

BECA 519


The BECA 519 profile is a double acting composite piston seal composed of a polyurethane friction ring and a profiled rubber ring.


Good sealing in static and dynamic applications
The square ring does not twist under pressure
Suitable for reduced axial size

Technical data




40 MPa


0.5 m/s


Mineral hydraulic oils


Mobile machinery
Injection presses
Hydraulic cylinders


Profiled seal

NBR 70 Shore A if ØD1 ≤ 63.00 mm
NBR 80 Shore A if Ø D1 > 63.00 mm

Friction ring

PU 93 Shore A - Blue
PU 96 Shore A - Blue
High temp. PU 96 Shore A - Beige
TPC-E (Hytrel)

Technical data


Installation drawingLogement Gorge Joint de piston - Housing Groove Gland Piston seal BECA 519



Polyurethane is a material that has the elastic properties of rubber. The proportion in its composition (diisocyanate, polyol, chain extender) is determined by its properties. This material is characterised by a strong mechanical resistance, good wear resistance, high elastic modulus, good flexibility and a very good ozone and oxidation resistance.

Chemical resistance Pure aliphatic hydrocarbons (propane, butane)
Mineral oils and greases
Silicone oils and greases
Water up to +50°C
Compatibility issue Ketones, esters, ethers, alcohols and glycols
Hot water, steam, alkalis, amines and acids
Temperature range -30°C/+90°C
-30°C / +110°C with our PUHT (short term peak at 150°C)


Nitrile rubber (NBR) is the general term for acrylonitrile-butadiene copolymer. The ACN content can vary between 18% and 50%. While the acrylonitrile content is important, the resistance to oil and fuel is more so. Conversely, the elasticity and compression set are not as good. The NBR has good mechanical properties and good wear resistance. However, its resistance to atmospheric agents and the ozone is relatively low.

Chemical resistance Aliphatic hydrocarbons (propane, butane, petroleum, diesel fuel)
Mineral oils and greases
Fire-resistant fluids (HFA, HFB and HFC)
Diluted acids, low-temperature alkaline and saline solutions
Water (up to +100°C max)
Compatibility issue Fuels with high aromatic content
Aromatic hydrocarbons (benzene)
Chlorinated hydrocarbons (trichlorethylene)
Polar solvents (ketone, acetone, acetic acid, ethylene-ester)
Strong acids
Glycol-based brake fluids
Atmospheric and ozone agents
Temperature range -30°C/+100°C
-40°C / +100°C with our low-temperature NBR

Technical data

Housing Groove Gland Piston Seal - BECA - 519

Extrusion gaps

Radial section
Radial extrusion gap
10 MPa 25 MPa 35 MPa 40 MPa
3.75 0.30 0.20 --- ---
5.50 0.40 0.30 0.20 ---
7.75 0.50 0.40 0.30 0.25
10.50 0.60 0.50 0.40 0.35
12.50 0.65 0.55 0.45 0.40

Surface roughness

Roughness Dynamic surface area Static surface area Groove flanks
Ra 0.1 - 0.4 µm ≤ 1.6 µm ≤ 3.2 µm
Rz 0.63 - 2.5 µm ≤ 6.3 µm ≤ 10.0 µm
Rmax 1.0 - 4.0 µm ≤ 10.0 µm ≤ 16.0 µm

Chamfers and radius

Radial section
Radius R1 Chamfer C
3.75 0.20 2.00
5.50 0.30 2.50
7.75 0.30 3.00
10.50 0.40 5.00
12.50 0.40 9.00

Only on request