Piston seals for hydraulic cylinders

The design of a piston seal is crucial for the function of the entire assembly. There is a wide range of profiles on the market – we help our customers and interested clients to make the optimal selection.

Standard profiles

By the standard profiles shown, we mean seals that represent the state of the art. We manufacture these standard seals ourselves or supply them as moulded parts from tested partners for all required groove dimensions from a variety of materials. Inch and intermediate sizes, but also largest diameters up to 3000 mm can be realized.

Depending on the quantity, the material and your requirements, we can offer you seals from the appropriate manufacturing process – all from a single source!

You can also find a general overview and further information in the following categories:

U-Cups and chevron sets
Compact piston seals
Piston seals with leader elements made of elastomer

Choosing the correct profile

The more information is known, the better the sealing system can be adapted to the application.

To choose the right profile and the optimal material, the following criteria are important:

installation space
double-acting or single-acting
pressure range
temperature range
medium
stroke speed
counterface
mounting possibility
friction behavior
stick-slip behavior
tightness
service life expectancy
price
availability

Piston seals – U-Cups and chevron sets

Application U-Cups

high tightness
for all hydraulic and pneumatic applications
one-sided, symmetrical sealing profile
assembly in closed grooves possible
many dimensions available as molded parts
inch and intermediate sizes as well as largest diameters can be realized

Application chevron sets

high tightness
single acting sealing element
available in slotted design
fields of application: mining, presses, special machine construction
adjustable if required

Pressure range:	up to 400 bar*
Sliding speeds:	up to 0,5 m/s
Temperature range:	-55 to +220 °C (depending on material)

* Special solutions for U-Cups for higher pressures up to 700 bar can be realized!

Piston seal
DK 101

Application:
Standard piston seal (u-cups)

Materials:
H-PU (up to 400bar, -30 to 100°C), NBR (up to 160bar), FPM (up to 160 bar, -30 to 200°C), EPDM, LT-PU, other materials on request.

Stroke speed:
max. 0.5 m/s

Special features:
Large selection of standard dimensions available as moulded part

Piston seal
DK 102

Application:
Standard piston seal (u-cups) with triangular support ring, for larger sealing gap or pulsating pressure.

Materials:
H-PU (up to 400bar, -30 to 100°C), NBR (up to 160bar), FPM (up to 160 bar, -30 to 200°C), EPDM, LT-PU, other materials on request.

Back-up ring material:
PTFE, PTFE compounds, POM, PEEK, PA

Stroke speed:
max. 0.5 m/s

Piston seal
DK 102 R

Application:
Standard piston seal (u-cups) with back-up ring, for larger sealing gap or pulsating pressure.

Materials:
H-PU (up to 400bar, -30 to 100°C), NBR (up to 160bar), FPM (up to 160 bar, -30 to 200°C), EPDM, LT-PU, other materials on request.

Back-up ring material:
PTFE, PTFE compounds, POM, PEEK, PA

Stroke speed:
max. 0.5 m/s

Piston seal
DK 103

Application:
U-Cup with additional preload element, increased tightness in depressurized condition

Materials:
H-PU (up to 400bar, -30 to 100°C), NBR (up to 160bar), FPM (up to 160 bar, -30 to 200°C), EPDM, LT-PU, other materials on request.

Preload element:
NBR, FPM, EPDM, other materials on request

Piston seal
DK 104

Application:
U-Cup with additional preload element and triangular support ring, low pressure range, increased tightness in depressurized condition

Materials:
H-PU (up to 400bar, -30 to 100°C), NBR (up to 160bar), FPM (up to 160 bar, -30 to 200°C), EPDM, LT-PU, other materials on request.

Preload element:
NBR, FPM, EPDM, other materials on request

Back-up ring material:
PTFE, PTFE compounds, POM, PEEK, PA

Stroke speed:
max. 0.5 m/s

Piston seal
DK 104 R

Application:
U-Cup with additional preload element and support ring, low pressure range, increased tightness in depressurized condition

Materials:
H-PU (up to 400bar, -30 to 100°C), NBR (up to 160bar), FPM (up to 160 bar, -30 to 200°C), EPDM, LT-PU, Other materials on request.

Preload element:
NBR, FPM, EPDM, other materials on request

Back-up ring material:
PTFE, PTFE compounds, POM, PEEK, PA

Stroke speed:
max. 0.5 m/s

Piston seal
DK 105 P

Application:
U-Cup for pneumatics with round sealing lip.

Materials:
H-PU (up to 400bar, -30 to 100°C), NBR (up to 160bar), FPM (up to 160 bar, -30 to 200°C), EPDM, LT-PU, other materials on request.

Stroke speed:
max. 0.5 m/s

Piston seal
DK 106

Application:
Symmetrical U-cup for rod and piston sealing.

Materials:
H-PU (up to 400bar, -30 to 100°C), NBR (up to 160bar), FPM (up to 160 bar, -30 to 200°C), EPDM, LT-PU, other materials on request.

Stroke speed:
max. 0.5 m/s

Piston seal
DK 107

Application:
Symmetrical U-Cup for rod and piston sealing with additional preload element and back-up ring, low pressure range, increased tightness in depressurized condition.

Materials:
H-PU (up to 400bar, -30 to 100°C), NBR (up to 160bar), FPM (up to 160 bar, -30 to 200°C), EPDM, LT-PU, other materials on request.

Preload element:
NBR, FPM, EPDM, Other materials on request

Stroke speed:
max. 0.5 m/s

Piston seal
DK 110-112

Chevron set. If standard dimensions are not available V-rings made of PU, NBR, FPM, POM, PE1000, PTFE-combounds possible. As standard made of NBR, NBR fabric, FPM, FPM fabric. If necessary, also pressure and support ring made of POM PE1000, PA, PTFE compound, gunmetal etc. possible. Slotted design also available. Good selection of standard dimensions available from stock.

Piston seal
DK 116

No longer recommended for new construction.

Materials:
H-PU, NBR, FPM, EPDM

Piston seal
DK 118

Proven symmetrical profile with high preload in the low-pressure range, good tightness, no longer for new constructions.

Piston seal
DK 124

single sleeve for use in commercial chevron set in case of repair. Original sample is advantageous.

Piston seal
DK 141

classic pneumatic profile made of NBR also with radius on the sealing edge, hydraulic insert up to 160 bar.

Piston seal
DK 199

Piston seal
DK 205

symmetrical pneumatic seal for universal use, mostly made of NBR

Piston seal
DK 216

No longer recommended for new construction.

Materials:
H-PU, NBR, FPM, EPDM

Compact piston seals

Application

The compact piston seal is a double-acting sealing and guiding element. It is available in various designs and is ideally suited to a wide range of applications. In principle:

universal use with standard cylinders
cost-effective with standard dimensions
compact installation space

Pressure range:	up to 400 bar
Sliding speeds:	up to 0,5 m/s
Temperature range:	-55 to +220 °C (depending on material)

Piston seal
DK 109

Universal compact piston seal, very wide range of applications, many standard dimensions available from stock, also special designs for low temperature, inch dimensions, special diameters after cylinder repair etc. possible.

Compact piston seal heavy duty mostly for mining and special applications.

Piston seal
DK 120

Compact piston seals for special applications e.g. mining, construction machinery etc.

Piston seal
DK 122

Compact piston seals for special applications e.g. mining, construction machinery etc.

X-ring or quad ring, many standard dimensions in stock, picture shows a turned X-ring.

Piston seal
DK 127

Application:
Robust double-acting compact seal usually made of PU, preferred for static use, also as replacement for O-rings and O-rings with back-up ring. Up to 600 bar, with breathing gaps, short pressure rise time, nominal diameter up to 3000mm.

Materials:
H-PU, FPM, EPDM

Piston seal
DK 222

Compact piston seals for special applications e.g. mining, construction machinery etc.

Piston seal
DK 223

Piston seals with leader elements made of elastomer

Kolbendichtungen mit Vorspannelementen aus Elastomer

Application

single-acting and double-acting sealing elements
universal application
wide range of materials
low friction
high sliding speeds
no stick-slip effect
small installation space
long service life
inch and intermediate sizes up to a diameter of 3000 mm can be realized

Pressure range:	up to 600 bar
Sliding speeds:	up to 15 m/s
Temperature range:	-55 to +280 °C (depending on material)

Piston seal
DK 108

Application:
Double-acting piston seal with O-ring as preload element, depending on material up to 800 bar, temperature range -50 to 280°C, diameter up to max. 3000 mm possible.

Material sealing ring:
PTFE compounds, POM, PEEK, PA, PE1000, PU, other materials on request.

Preload element material:
NBR, FPM, EPDM, other materials on request.

Piston seal
DK 108 R

Application:
Double-acting piston seal with O-ring as preload element and back-up rings on both sides, material-dependent up to 600 bar, temperature range -50 to 280°C, diameter up to max. 3000 mm possible.

Sealing ring material:
PTFE compounds, POM, PEEK, PA, PE1000, PU, other materials on request.

Preload element material:
NBR, FPM, EPDM, other materials on request

Back-up ring material:
PTFE, PTFE compounds, POM, PEEK, PA

Piston seal
DK 125

Application:
Single acting piston seal with O-ring as preload element, material dependent up to 400 bar, temperature range -50 to 280°C, diameter up to max. 3000 mm possible.

Material sealing ring:
PTFE compounds, POM, PEEK, PA, PE1000, PU, other materials on request.

Preload element material:
NBR, FPM, EPDM, other materials on request.

Piston seal
DK 125 R

Application:
Single acting piston seal with O-ring as preload element and back-up ring, material dependent up to 600 bar, temperature range -50 to 280°C, diameter up to max. 3000 mm possible.

Seal ring material:
PTFE compounds, POM, PEEK, PA, PE1000, PU, other materials on request.

Preload element material:
NBR, FPM, EPDM, Other materials on request

Back-up ring material:
PTFE, PTFE compounds, POM, PEEK, PA

Piston seal
DK 138

Application:
Double acting piston seal with rectangular profile as preload element, for large diameters material dependent up to 400 bar, temperature range -50 to 280°C, diameter up to max. 3000 mm possible.

Seal ring material:
PTFE compounds, POM, PEEK, PA, PE1000, PU, other materials on request.

Preload element material:
NBR, FPM, EPDM, other materials on request.

Piston seal
DK 140

Double-acting piston seal set, outer ring mostly made of PU, high tightness, very good service life, very wide range of dimensions. Many standard dimensions available at short notice.

Piston seal
DK 142

small-diameter piston seal set, originally designed for existing O-ring grooves, outer ring made of PTFE and PTFE compounds, wide range of dimensions.

Piston seal
DK 143

for high-frequency applications optionally with O ring or rectangular ring as preload element. Running ring made of PTFE compound. Use only after consultation.

Piston seal
DK 144

Double-acting piston seal with 2 O-rings as preload element. This results in a more defined contact pressure of the sealing edges, but is also suitable for less deep installation grooves. Elestomer part (X-ring) on the running surface causes increased sealing effect. Very wide range of applications. Material and medium dependent up to 600 bar, temperature range -50 to 200°C. Outer ring mostly made of PTFE compound, but also POM, PEEK, PA, PE1000 etc. possible. Almost any diameter up to max. 3000 mm possible. Special designs for use under radiation exposure, for aggressive media and many more. Selection after consultation.

Piston seal
DK 145

Double-acting piston seal with O-ring as preload element. This results in a more defined contact pressure of the sealing edges. Elestomer part (X-ring) on the running surface causes increased sealing effect. Very wide range of applications. Material and medium dependent up to 600 bar, temperature range -50 to 200°C. Outer ring mostly made of PTFE compound, but also POM, PEEK, PA, PE1000 etc. possible. Almost any diameter up to max. 3000 mm possible. Special designs for use under radiation exposure, for aggressive media and many more. Selection after consultation.

Piston seal
DK 238

Application:
Single acting piston seal with rectangular profile as preload element, for large diameters material dependent up to 400 bar, temperature range -50 to 280°C, diameter up to max. 3000 mm possible.

Seal ring material:
PTFE compounds, POM, PEEK, PA, PE1000, PU, other materials on request.

Preload element material:
NBR, FPM, EPDM, other materials on request.

Piston seals for hydraulic cylinders

Piston seals – U-Cups and chevron sets

Compact piston seals

Piston seals with leader elements made of elastomer

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