Reciprocating Seals
Reciprocating seals covers extremely wide range of applications. These seals are a dynamic version of either a male radial or female radial O-ring design. In a reciprocating seal, there is relative reciprocating motion (along the shaft axis) between the inner and outer elements. This motion tends to slide or roll the O-ring, or sealing surface of the O-ring, back and forth with the reciprocal motion. Examples of a reciprocating seal would be a piston in a cylinder, a plunger entering a chamber, and a hydraulic actuator with the piston rod anchored.




| Single Acting Seal | Double Acting Seal |
Application | Standard Cylinders | Standard Cylinders |
| Light and medium mobile hydraulics | Light and medium mobile hydraulics |
Operating Conditions |
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Temperature | Temperature: -50°C to +250 °C | Temperature: -50°C to +250 °C |
Pressure | 800 bar | 800 bar |
Linear Velocity | 15 m/s | 15 m/s |
Fittings | Careful fitting is a prerequisite for proper functioning of the seal | Careful fitting is a prerequisite for proper functioning of the seal |
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Advantages | Low Friction | Low Friction |
| No stic-slip | No stic-slip |
| Minimised ‘break-out’ forces | Minimised ‘break-out’ forces |
| Wear Resistant | Wear Resistant |
| Simple groove design | Simple groove design |
1. Piston Seals

Single & double acting piston seals
Piston seals are used to create a seal between the piston and the cylinder bore, preventing leakage of hydraulic fluid or air. This seal is internal to the cylinder and allows pressure to be maintained on one side of the piston, creating the force to move it back and forth. Piston Seal profiles are available as single acting (pressure from one side) or double acting (pressure from both sides).
Materials
The chosen piston seal material influences the choice of seal profile. Depending on the profile and the required characteristics, a piston seal can consist of one or several materials. Common piston seal materials are Polyurethane (PU) and polytetrafluorethylene (PTFE)
2. Rod Seals

Reciprocating rod seals are widely used in hydraulic systems to prevent the hydraulic fluid from leaking into and polluting the environment. Additionally. Rod Seals help contribute, in combination with a Wiper Seal, to preventing contamination of the environment. The Rod Seal profiles are available as single acting (pressure from one side) or double acting (pressure from both sides). High pressure Rod Seal applications often require an additional Buffer Seal, profile below, to assist with pressure spikes
Materials
Primary Piston Seal materials are Polyurethane and PTFE blends. Specific Triumph Rod Seal materials are outlined below.
Rod Seal applications can be very demanding on the seals, Triumph Engineers are available to consult on any Reciprocating Seal application. Click on the Engineering request to contact a Triumph Engineer
AFCB/AFCR
Radial rod and piston seals for static and dynamic applications. Typically energised with a Helical tape wound spring but also very effective with an O-ring energiser. Spring pre-load is fairly high which gives an increase in seal friction but also very positive sealing. Generally used for high pressure applications. The heel length of this type of seal can be increased for higher pressure applications and these can be combined with Back-up rings as shown on page 9.
- Excellent static sealing
- High spring preload
- Higher seal friction
- Limited to open grooves except in large diameters
- Available up to 1850mm diameter
- Any groove depth and width can be accommodated with bespoke profiles
- Pressure up to 70 MPa/700 bar (Additional Back-up rings may allow more)
- Operating temperature -196°C to +260°C
Nominal Diameter | Groove Depth | Groove Width Standard | |||
10–20mm | 2.26/2.31 | 3.60 | 4.60 | 0.12 | 0.4 |
20–40mm | 3.07/3.12 | 4.80 | 6.00 | 0.14 | 0.4 |
40–120mm | 4.67/4.73 | 7.10 | 8.50 | 0.16 | 0.6 |
120–500mm | 6.07/6.13 | 9.50 | 12.10 | 0.20 | 0.6 |
500–1200mm | 9.35/9.40 | 13.50 | 15.00 | 0.22 | 0.8 |
AFVB/AFVR
Radial rod and piston seals for static and dynamic applications. Typically energised with a V (cantilever) or canted coil spring. Spring pre-load is light to medium which keeps friction lower. High seal deflection can be tolerated without permanent deformation. The heel length of this type of seal can be increased for higher pressure applications and these can also be combined with Back-up rings as shown on page 9 for higher pressure applications. Often used in Valve stems for high pressure slow rotary dynamic applications or linear reciprocating seals up to 15m/s.- Excellent dynamic sealing particularly in reciprocating applications up to 15m/s
- Lower seal friction
- Limited to open grooves except in large diameters
- Available up to 1850mm diameter
- Any groove depth and width can be accommodated with bespoke profiles
- Pressure up to 45 MPa/450 bar
- Surface speeds up to 15 M/S
- Operating temperature -80°C to +260°C
Nominal Diameter | Groove Depth | Groove Width Standard | Groove Width Extended | Max Gap (Radial Clearance) | RMax |
10–20mm | 2.26/2.31 | 3.60 | 4.60 | 0.12 | 0.4 |
20–40mm | 3.07/3.12 | 4.80 | 6.00 | 0.14 | 0.4 |
40–120mm | 4.67/4.73 | 7.10 | 8.50 | 0.16 | 0.6 |
120–500mm | 6.07/6.13 | 9.50 | 12.10 | 0.20 | 0.6 |
500–1200mm | 9.35/9.40 | 13.50 | 15.00 | 0.22 | 0.8 |
AFCCB/AFCCR
Radial rod and piston seals for static and dynamic applications. Energised with a canted coil spring. Spring pre-load is light to medium which keeps friction lower and allows the seals to cope with slight misalignment. High seal deflection can be tolerated without permanent deformation. Permanent deformation is defended by the canted coil spring in full compression acting as a solid stop. The heel length of this type of seal, similar to others, can be increased for higher pressure applications and these can also be combined with any combination of back up rings as shown on page 9 for higher pressure applications. Often used in valve stems for high pressure slow rotary dynamic applications or linear reciprocating seals up to 15m/s. Canted coil spring gives a constant energizer pressure regardless of level of pre-load compression
- Excellent Dynamic sealing particularly in reciprocation applications up to 15m/s
- Lower seal friction
- Available up to 1850mm diameter
- Any groove depth and width can be accommodated with bespoke profiles
- Pressure up to 45 MPa/450 bar
- Surface speeds up to 15m/s
- Operating temperature -80°C to + 260°C
Nominal Diameter | Groove Depth | Groove Width Standard | Groove Width Extended | Max Gap (Radial Clearance) | RMax |
10–20mm | 2.26/2.31 | 3.60 | 4.60 | 0.12 | 0.4 |
20–40mm | 3.07/3.12 | 4.80 | 6.00 | 0.14 | 0.4 |
40–120mm | 4.67/4.73 | 7.10 | 8.50 | 0.16 | 0.6 |
120–500mm | 6.07/6.13 | 9.50 | 12.10 | 0.20 | 0.6 |
500–1200mm | 9.35/9.40 | 13.50 | 15.00 | 0.22 | 0.8 |
Examples shown feature contoured profile for easier assembly and also a scraper lip which is specific to reciprocating. These are available across the whole range of energised seals to suit individual requirements