Radial Seal MR21


Radial Seal MR21 is a double-acting seal for rotary movements and joint sealing and is used in hydraulic rotary transmission systems. The radial seal MR21 seal the space between the pressure lines, separating them from each other and is suitable for sealing high hydraulic pressures during rotating movements.

It consists of a PTFE profile ring and an O-ring as a preload element.

The radial seal MR21 has small dimensions, is highly resistant to hydraulic fluids and has very low friction and, by choosing the appropriate material, good resistance to high and low temperatures.

Swivel joints
Hose reels
High pressure valve stem
Diferent rotary distributors

Standard material
Material Set Code SN209 SF208
O-ring 70 ShA NBR FPM
Profile Ring PTFE glass,MoS2 PTFE glass,MoS2

For low temperature applications, or excellent medium-rubber compatibililty in special applications a few materials are recommended and available on request

Pressure, Speed
Working pressure, P Max 40 Mpa
Running speed v, Up to 0.2 m/s

Medium, Working Temperature
Material Code SN209 SF208
Hydraulic oils: HL, HLP -30.. +100 ˚C -10.. +150 ˚C
HFA, HBA fluids +5..+60 oC
HFC fluids -30..+60 oC
HFD fluids -10.. +150 ˚C
Water +5..+100oC
Mineral greases -30 to +100 -10.. +150 ˚C

Ød emax ØD
≤ 500 mm H8/f8 H9

Surface finish*
Surface roughness Ra Rmax
Sliding surfaces 0.05 .. 0,3μm ≤ 2.5 μm
Groove base ≤ 1.6 μm ≤ 6.3 μm
Groove flanks ≤ 3 μm ≤ 15 μm

*Contact area Mr = 50% to 90% at cutting depth c=Rz/2 and reference line Cref=0% Surface hardness must be 45 – 60 HRC with 0.5mm layer in depth