(pack) Piston-Rod Sealing U-ring K21 NBR ID 3mm-8mm (choose dimensions)

Description

Welcome to our oil seal store. Huge amount of different dimensions and materials are on stock!! Don´t hasitate to contact us. We also have o-ring store, bearing store,chain store,
hydraulic and pneumatic seals store, belt store, etc - we can send together.
Most of oil seals are on stock, so we are usually shipping within 2 bussiness days.
Longer handling time 10-20 days occures just on sold out items.
We can also use UPS express shipping. Shipping rates are: UPS to USA
30USD,
UPS to Europe, U.K, Germany, France
20USD,
UPS to N.a S.America, Canada, Mexico, Brazil, Asia, China, Japan, Australia
50USD
K21 is a single acting piston - rod seal and designed to have symmetrical lips in order to be used both for rod and piston applications.
PRODUCT ADVANTAGES
• Superior static and dynamic sealing eff­ect
• Wide range of dimensions
• Easy assembly into closed grooves
• Simple groove design
• Economical sealing solution
APPLICATION
Construction machinery , fork-lift trucks , injection moulding machines , agricultural machinery , loading platforms and standard cylinders.
MATERIAL           CODE
NBR       90 SHORE A        NB9001
PU          92 SHORE A       PU9201
OPERATING CONDITIONS
NBR
MEDIA  Mineral oils(DIN 51524)               HFA and HFB     HFC
TEMPERATURE  -30°C +105°C      +5°C +60°C          -30°C +60°C
PRESSURE           ≤150 Bar              ≤150 Bar              ≤150 Bar
SPEED   ≤0.5 m/sn           ≤0.5 m/sn           ≤0.5 m/sn
PU
MEDIA  Mineral oils(DIN 51524)               HFA and HFB     HFC
TEMPERATURE  -30°C +100°C      +5°C +50°C          -30°C +40°C
PRESSURE           ≤400 Bar              ≤400 Bar              ≤400 Bar
SPEED   ≤0.5 m/sn           ≤0.5 m/sn           ≤0.5 m/sn
Note: The above data are maximum values and cannot be used at the same time.
SURFACE ROUGHNESS  Ra           Rmax
Sliding Surface ØD-Ød  ≤0.4 μm               ≤3.2 μm
Groove Base ØDb-Ødp ≤1.6 μm               ≤10 μm
Groove Flanks B              ≤3.2 μm               ≤16 μm
Note: It is recommended to have 50% to 90% of the working surface material contact area value.
INSTALLATION
Easily assembled into closed grooves according to the minimum diameter values that are given in the below table. Open grooves or special assembly tools should be used for the values that are outside this table. It is very important that the assembly tools must be of soft material and have no sharp edges. Before installation the wiper must be oiled with system oil.
MINUMUM DIAMETER VALUES FOR CLOSED TYPE OF GROOVES
(D-d)/2 (mm)    4             5             6             7.7          10           12.5       15
dmin (mm)        25           30           40           50           80           100         105
NOTES For special applications that require high temperatures , K21 can be produced in FKM material. The permissible sealing gap values of K21 piston -rod seal is given in the below table.
PERMISSIBLE SEALING GAP
NBR    Smax (mm)
t=(D-d)/2            50 Bar   100 Bar 150 Bar
t≤5         0.40       0.20       0.10
t>5         0.45       0.25       0.15
PU       Smax (mm)
t=(D-d)/2            150 Bar 250 Bar 400 Bar
t≤5         0.30       0.20       0.15
t>5         0.35       0.25       0.20
Note: The largest sealing gap value occurring on the non-pressurized side of the seal does have a vital importance for the function of the seal and in this respect it is quite important to use the S value lower than the above indicated numbers.