Hydraulic Seals | Piston Seals | Merkel Compact Seal HDP 330

Merkel Compact Seal HDP 330

Operating conditions
Pressure p 60 MPa
Sliding * Pressure max. static p = 80 MPa at T = 100 °C
element Running speed v 0,8 m/s
Contact pressure
element Medium/­
PA 4112/70 NBR 177605
Temperature
Hydraulic oils HL, HLP –30 °C … +100 °C
HFA fluids +5 °C … +55 °C
HFB fluids +5 °C … +60 °C
HFC fluids –30 °C … +60 °C
Product description HFD fluids –
Two-part seal set for sealing pistons, consisting of a PA slide ring Water –
HETG (rapeseed oil) –30 °C … +60 °C
with a stepped cut and an elastomer contact pressure element
HEES (synthetic ester) –30 °C … +80 °C
for producing pre-load. HEPG (glycol) –30 °C … +80 °C
Mineral greases –30 °C … +100 °C

Product advantages
Design notes
■■ Extreme strength against gap extrusion thanks to the PA sliding
component Please observe our general design notes in ➔ Technical Manual.
■■ Extremely high abrasion resistance
Surface quality
■■ Stepped cut for easy fitting in a closed housing
Peak-to-valley
■■ Greater surface roughness partly permissible in comparison to heights
Pressure range Ra Rmax
conventional seals Sliding surface ≤26 MPa 0,05 … 0,5 µm ≤5 µm
■■ Rectangular contact pressure element produces consistently Sliding surface ≤60 MPa 0,05 … 0,3 µm ≤2,5 µm
high pre-loading force and offers high protection against Groove base ≤1,6 µm ≤6,3 µm
twisting in the housing Groove flanks ≤3 µm ≤15 µm

■■ Housings should preferably comply with ISO 7425-1 Percentage contact area Mr >50% to max 90% at a depth of cut c = Rz/2 and reference line
Cref = 0%. Rougher surfaces, in combination with higher stroke frequencies, can lead to oil
■■ Dynamic and static tightness comparable to PTFE piston seals depletion in the lubricating gap.

Admissible gap dimension

Application The maximum gap to appear results from the tolerances, guide
■■ Earth moving equipment play, compressive deflection of the guide under load, and the
■■ Industrial vehicles cylinder divergence. ➔ Technical Manual.
■■ Loading platforms Profile
■■ Agricultural machinery dimen- 16 MPa 26 MPa 32 MPa 40 MPa 50 MPa 60 MPa
sion
3,75 mm 0,50 mm 0,50 mm 0,50 mm 0,45 mm 0,35 mm 0,30 mm
Material 5,50 mm 0,55 mm 0,55 mm 0,55 mm 0,50 mm 0,40 mm 0,35 mm
7,75 mm 0,75 mm 0,75 mm 0,75 mm 0,70 mm 0,55 mm 0,50 mm
Slide ring 10,50 mm 1,00 mm 1,00 mm 1,00 mm 0,95 mm 0,75 mm 0,65 mm
Material Code Hardness
These gap dimensions apply to: the upper operating temperatures of Tmax = 100 °C, the
Fibreglass filled modified
PA 4112 – tolerance recommendations for cylinders, groove base and guide. ➔ Technical Manual.
polyamide

Tolerances
Contact pressure element
When dimensioning the d2 for the admissible gap width, the
Material Code Hardness
Nitrile rubber NBR 70 NBR 177605 70 Shore A permissible tolerances, the guide play and the deflection of the
guide should be accounted for. ➔ Technical Manual

Fitting & installation

Careful fitting is a prerequisite for the correct function of the seal.

➔ Technical Manual.

© Freudenberg Simrit GmbH & Co. KG | Seals for Fluid Power eCatalog 2009 1