Seals For Hydraulic Equipments
Seals for Hydraulic Equipment's
Rod Seals
Rod Seals are used in hydraulic cylinder systems to prevent fluid from escaping the cylinder. Machined grooves in the cylinder housing allow the rod ring to seal directly against the piston shaft. Rod seals are particularly exposed to pressure and friction and a long service life is a specific requirement of piston rod. Rod seal is a high performance general purpose seal which can offer this with its outstanding wear and extrusion resistance.
SINGLE LEAP U-CUP SEALS
| PRESSURE | MATERIALS | FEATURES | APPLICATIONS |
|---|---|---|---|
| 5000-5500 PSI | PU | Pressure energized seal | Mobile Hydraulic |
| Temperature Range | Nitrile | Film breaking | Agricultural |
| (50)-+250˚ F | Viton | Improved stability | General Industrial |
| Velocity | Improved extrusion resistance | Medium duty cycle | |
| 3.2 Feet/Sec | High duty cycle |
DOUBLE LIP U-CUM SEALS
| PRESSURE | MATERIALS | FEATURES | APPLICATIONS |
|---|---|---|---|
| 5000-5500 PSI | PU | Low compression set | Heavy Duty |
| Temperature Range | Nitrile | Secondary Lip | Mobile Hydraulic |
| (50)-+250˚ F | Viton | Extrusion resistant base | Telescopic Cylinder |
| Velocity 3.2 Feet/Sec | Hytrel | Low temparature sealing | High duty cycle |
SPRING ENERGISED
| PRESSURE | MATERIALS | FEATURES | APPLICATIONS |
|---|---|---|---|
| 10000 PSI | PU | Low compression set | Petro-chemical |
| Temperature Range | PTFE | Secondary Lip | Low friction |
| (450)-+550˚ F | SS Spring | Low friction | Extreme temperatures |
| Velocity | Low temparature sealing | Corrosive fluids | |
| 3.2 Feet/Sec | Custom designs | High duty cycle |
STEP SEAL
| PRESSURE | MATERIALS | FEATURES | APPLICATIONS |
|---|---|---|---|
| 10000 PSI | Filled PTFE | Protects Rod seals from pressure spikes | Any application requires |
| Temperature Range | PTFE | Lower friction | secondary sealing to reduce effects of pressure spikes |
| (50)-+250˚ F | SS Spring | Vents back pressure | Medium duty cycle |
| Velocity 3.2 Feet/Sec | Longer life |
Piston Seals
Piston Seals or Piston Rings are used in hydraulic cylinders for fluid sealing. the piston seal is required to maintain high level of sealing performance and allow the necessary lubrication during the service life.
U-CUP PISTON SEALS
| PRESSURE | MATERIALS | FEATURES | APPLICATIONS |
|---|---|---|---|
| 5500-6000 PSI | PU | Rectangular seal | Mobile |
| Temperature Range | Nitrile | Scrapper lip | hydraulic |
| Range | Viton | Improved stability | Agricultural |
| (50)-+250˚ F | EPDM | General Industrial Low pressure sealing | General |
| VELOCITY | Industrial | ||
| 3.2 Feet/Sec (0.7 feet/sec for asymmetrical U-Cup) | Low pressure sealing |
GLYD RING
| PRESSURE | MATERIALS | FEATURES | APPLICATIONS |
|---|---|---|---|
| 5000 PSI | Bronze | Low friction | Mobile hydraulic |
| Temperature Range | PTFE | Long service life | Agricultural |
| (65)-+400˚ F | Carbon Graphite PTFE | General Industrial | |
| VELOCITY 3.2 Feet/Sec | Moly PTFE | Heavy duty |
T SEAL
| PRESSURE | MATERIALS | FEATURES | APPLICATIONS |
|---|---|---|---|
| 5000 PSI | Nitrile | Square seal for stability | Retrofit standard industrial O ring grooves |
| Temperature Range | Viton | Low pressure sealing | |
| (65)-+400˚ F | EPDM | Anti extrusion rings | |
| VELOCITY 0.4 Feet/Sec | NBR NYLON PTFE | Dynamic sealing surface |
PISTON SEALS
| PRESSURE | MATERIALS | FEATURES | APPLICATIONS |
|---|---|---|---|
| 5000-5500 PSI | PU | Square seal for stability | Mobile hydraulic |
| Temperature Range | NBR | Energized seal | Agricultural |
| (50)-+250˚ F | O ring grooves | Heavy duty vacuums | |
| VELOCITY | Low pressure seal ability | Heavy duty hydraulic | |
| 0.3-0.7 Feet/Sec | Forklift | ||
| Standard hydraulic cylinders | Cranes | Stabilizer | Presses |
Wear Rings
The function of a hydraulic wear ring (also called as wear bands, slyd rings or bearings) is to guide the piston and piston rod of a hydraulic cylinder absorbing transverse forces. At the same time, it prevents metal to metal contact, optimizing the performance of the sealing system.
CUT TYPE
BUTT- CUT
ANGLE CUT
STEP CUT
| RADIAL THICKNESS |
|---|
| .062/.060 |
| .093/.091 |
| .125/.123 |
| .187/.185 |
| 1.5/1.45 |
| 2.00/1.95 |
| 2.50/2.45 |
| 3.00/2.95 |
| 3.50/3.45 |
| 4.00/3.95 |
| 5.00/4.95 |
| 6.00/5.95 |
Wipers
Wiper Seals (also known as Scrapers, Excluders or Dust Seals) are fitted on the external side of the cylinder head . Wiper performs essential functions for the proper protection of the hydraulic system and sealing element, so as to obstruct the contamination particles in the hydraulic system, which commanly causes breakdowns and damages to all internal components of the cylinder.
TYPES OF WIPER SEALS
| PRESSURE | MATERIALS | FEATURES | APPLICATIONS |
|---|---|---|---|
| 5000-5500 PSI | NBR | Performs essential functions for proper protection of hydraulic system & sealing element | Mobile hydraulic |
| PU | Agricultural | ||
| NBR-METAL | General industrial | ||
| PU-METAL | Medium duty cycle | ||
| GLASS FILLED PTFE | High duty cycle |
O Rings
O-Rings are often used as reciprocating seals in hydraulic and pneumatic systems. While best suited for short stroke, relatively small diameter applications, O-Rings have been used successfully in long stroke, larger diameter applications. O-Rings are used to prevent the passing of air or fluid. In other words, O-Rings are used to keep fluid or air IN or OUT of a defined space.
Materials used for O Ring
- NBR
- EPDM
- VITON
- PU
- PTFE
| Available Dimendional Range in mm | Shore Hardness Scale - A | Temperture Range Deg.-C |
|---|---|---|
| 5-400 | 70-95 | (-) 20 - 200 |
Back-up Rings
Back-up Rings or anti-extrusion rings are thin rings that are that are designed to prevent O-Ring extrusion under pressure. They fit in the gland between the seal and the clearance gaps to provide zero clearance. These are used when the fitting clearance between the sealing surface of the O-Rings is large enough to allow the O-rings to extrude all certain working pressure. A number of materials can be used for Back-up rings , but PTFE has the benefit of a very low friction in dynamic applications.
Materials used for Backup-up Rings
- PTFE
- NBR
- VITON
- PU
| Available Dimendional Range in mm | Shore Hardness Scale - A | Temperture Range Deg.-C |
|---|---|---|
| 10-500 | 95 | (-) 40 - 240 |
Assembly Suggestion
Incorrect seal assemblies cause damage to the lips and other parts of the seal, during the assembly process the following factors must be taken into consideration.
- All parts must be clean, without contamination, metal score marks, welding splatter or any kind of defect.
- Avoid using pointed and sharp metal tools and avoid keeping the seal in a deformed position for long periods of time.
- All seals and connecting parts must be lubricated before assembly using the same compatible fluid that will be used in the hydraulic system.
- The seal must not come into contact with corners, holes wrongly beveled or threads during assembly.
- Check the dimensions, roughness and beveling shape properly.