Spring-energized seals or radial seals
The spring-energized seals are designated for sealing of rotating machine parts and units filled by oils, greases, and by other liquid substances. Selection of due seals depends on existing operation parameters (environment, temperature, surface speed, etc.).
As a rule, the spring-energized seal consists of reinforcing metal ring, rubber parts, and of a draw spring, laid out with or without dust cap.
Standard materials:
Rubber material of radial seals:
|
Basis of elastomer |
DIN ISO 1629 |
Hardness [Shore A] |
Colour | Temperature [° C] |
|
Acrylnitrile-Butadiene-Rubber |
NBR |
70 | black |
- 40 up to + 100 for a short term + 120 |
|
Fluorine-Rubber |
FPM |
80 | brown | - 30 up to + 200 |
PTFE material of WEPO and WCP21 rubbers:
|
Basis of elastomer |
DIN EN ISO 1043- 1 |
Filler |
Hardness [Shore A] |
Temperature [° C] |
Form |
|
Acrylnitrile-Butadiene-Rubber |
PTFE |
carbon/graphite | 62 | - 30 up to + 205 | WEPO |
|
Fluorine-Rubber |
PTFE |
glass fibre/MoS2 |
60 - 80 | - 90 up to + 250 | WCP21 |
Special materials:
|
Basis of elastomer |
DIN ISO 1629 |
Hardness [Shore A] |
Colour | Temperature [° C] |
|
Silicone-Rubber |
VMQ |
70 | red | - 50 up to + 200 |
|
Acrylate-Rubber |
ACM | 70 | black | - 25 up to + 150 |
|
Ethylene-Propylene-Diene-Rubber |
EPDM |
70 | black | - 40 up to + 130 |
The shaft's surface speed
The shaft's surface speed corresponds to the slide speed of the mutual movement of sealing surfaces.
Diagram defining applicability of a seal as related to surface speed for individual material types:
Working pressure by standard spring-energized seals
|
max. pressure [bar] |
rpm [min-1] |
max. speed [m/s] |
|
0,5 |
do 1000 |
2,8 |
|
0,35 |
do 2000 |
3,15 |
|
0,2 |
do 3000 |
5,6 |
Radial seal - type WA
- The WA shape has its external mantle of elastomer, which provides a very good static sealing.
- Corrosion of face side does not occur.
- More frequent exchange of the seal will prevent the damage of the seal seating hole.
- Designated for sealing of gaseous or thin liquid media.
Material :
- NBR 70
- Colour: black
- Reinforcing ring: plain steel
- Spring: plain spring steel
Operation values:
- pressure [MPa/bar] : ≤ 0,05/0,5
- temperature [°C] : -40 up to +100
- speed [m/s] : ≤ 1
Radial seal - type WAS
- With dust cap against impurities and danger of corrosion
Material :
- NBR 70
- Colour: black
- Reinforcing ring: plain steel
- Spring: plain spring steel
Operation values:
- pressure [MPa/bar] : ≤ 0,05/0,5
- temperature [°C] : -40 up to +100
- speed [m/s] : ≤ 12
Radial seal – type WB
- It is characteristic for a metal external mantle.
- It secures firm and precise seating in a case.
- Tolerance of the seating hole is required so as to reach the sealing on the external mantle.
- Good quality of the mantle surface is necessary.
Material :
- NBR 70
- Colour: black
- Reinforcing ring: plain steel
- Spring: plain spring steel
Operation values:
- pressure [MPa/bar] : ≤ 0,05/0,5
- temperature [°C] : -40 up to +100
- speed [m/s] : ≤ 12
Radial seal – type WBS
- With dust cap against impurities and danger of corrosion
Material :
- NBR 70
- Colour: black
- Reinforcing ring: plain steel
- Spring: plain spring steel
Operation values:
- pressure [MPa/bar] : ≤ 0,05/0,5
- temperature [°C] : -40 up to +100
- speed [m/s] : ≤ 12
Radial seal - type WC
- Metal layer with a reinforcing cap.
- Packing and installation as with the WB.
- Used under especially heavy operation conditions, in rolling mills, for farming and logging machines, in windmills.
- Due to its increased stiffness, this radial seal is suitable under heavy-duty installation conditions of larger dimensions.
Material :
- NBR 70
- Colour: black
- Reinforcing ring: plain steel
- Spring: plain spring steel
Operation values:
- pressure [MPa/bar] : ≤ 0,05/0,5
- temperature [°C] : -40 up to +100
- speed [m/s] : ≤ 12
Radial seal - type WCS
- With dust cap against impurities and danger of corrosion
Material :
- NBR 70
- Colour: black
- Reinforcing ring: plain steel
- Spring: plain spring steel
Operation values:
- pressure [MPa/bar] : ≤ 0,05/0,5
- temperature [°C] : -40 up to +100
- speed [m/s] : ≤ 12
Radial seal - type VIA
- Radial seal with viton mantle and with metal reinforcing ring.
- The FPM material is more suitable for high temperatures, high speeds, and resists chemically aggressive media.
Material :
- FPM 80
- Colour: brown
- Reinforcing ring: plain steel
- Spring: stainless and acidproof steel
Operation values:
- pressure [MPa/bar] : ≤ 0,05/0,5
- temperature [°C] : -30 up to +200
- speed [m/s] : ≤ 35
Radial seal – type VIAS
- With dust cap against impurities and danger of corrosion
Material :
- FPM 80
- Colour: brown
- Reinforcing ring: plain steel
- Spring: stainless and acidproof steel
Operation values:
- pressure [MPa/bar] : ≤ 0,05/0,5
- temperature [°C] : -30 up to +200
- speed [m/s] : ≤ 35
Radial seal - type WAO
- It has a grooved external mantle of elastomer, metal reinforcing ring and sealing lip without spring.
- Advantage: low friction.
- The external mantle of elastomer enables good static sealing and offers good accommodation of the thermal expansion.
- Upon higher roughness secures better sealing properties for liquid or gaseous media.
Material :
- NBR 70
- Colour: green/black
- Reinforcing ring: plain steel
Operation values:
- pressure [MPa/bar] : ≤ 0/0
- temperature [°C] : -40 up to +100
- speed [m/s] : ≤ 6
Radial seal - type WBO
- Radial seal with metal external mantle, without spring.
Material :
- NBR 70
- Colour: green/black
- Reinforcing ring: plain steel
Operation values:
- pressure [MPa/bar] : ≤ 0/0
- temperature [°C] : -40 up to +100
- speed [m/s] : ≤ 6
Radial seal - type WAD
- Radial spring with two sealing lips and external rubber mantle.
- Especially for sealing two media or heavy pollution from outside.
Material :
- NBR 70
- Colour: black
- Reinforcing ring: plain steel
- Spring: plain spring steel
Operation values:
- pressure [MPa/bar] : ≤ 0,03/0,3
- temperature [°C] : -40 up to +100
- speed [m/s] : ≤ 6
Radial seal - type WBD
- Radial spring with two sealing lips and external rubber mantle.
- Especially for sealing two media or heavy pollution from outside.
Material :
- NBR 70
- Colour: green/black
- Metal case: plain steel
- Spring: plain spring steel
Operation values:
- pressure [MPa/bar] : ≤ 0,03/0,3
- temperature [°C] : -40 up to +100
- speed [m/s] : ≤ 6
Type WCP21
- Radial seal with the sealing lip of PTFE and with rubber pre-stressing ring, that are installed between two metal cases.
- The PTFE's very low friction coefficient prevents stammering, reduces start-up resistance, and is suitable on dry run or on insufficient lubrication.
- Applicable for higher speeds, higher pressure load, and for higher temperatures.
- For sealing aggressive chemicals (excellent technical stability of PTFE).
- Various layouts feature one or two lips.
Material :
- razor edge sealing: PTFE + fibreglass / MoS2
- Colour: grey
- Metal case: stainless and acidproof steel
- Rubber part: FPM
Operation values:
- pressure [bar] : 5 bar / 10 bar / 25 bar
- temperature [°C] : -90 up to +250
- speed [m/s] : ≤ 40