Operational behaviour inflatable sealing systems

Mechanical and environmental performance of
Wolf GmbH inflatable sealing systems

Advantages of our air-filled sealing systems

  • Long service lifetime due to the extremely low leak rate (diffusion) of the sealing cushion
  • Patented CO2-neutral inflation technology; the cushion is inflated with air to protect the environment
  • Reusable cushion types (i.e. all sealing systems with valves and tyre valve connections (SSB2)) reduce maintenance costs, thanks to savings on material costs when retrofitting cables
  • Valve sealing systems allow filling-pressure monitoring and pressure can be topped up if necessary
  • Suitable for temperature range:
    -15°C to +30°C (+45°C (4 h))    PI 19.1 | 19.2 | 19.3 | 19.4 | 20.3 | 20.6



Calculation of service lifetime

  1. Computational determination of service lifetime

    The values for service lifetime are based on the total leak rate (diffusion) values measured by the GEMTEC testing institute and the results of ageing tests carried out in the Fibre Optics CT GmbH testing lab.

Extract from the GEMTEC test report (full report available on request)
1.1 “Determination of the total leak rate of sealing elements”


Test setup:
The test sample was laid in a plastic duct supplied by the customer and filled with the test gas
(100 % SF6) at a pressure of 2.8 bar (abs.).

Swelling Sealing Bags SSB/SSB2
Samples A and B. After pressure-filling, the filling tube was crimped with the original crimping tool in accordance with the instructions provided.

Sealing cushion with valve
After pressure-filling, sample D was stored alternately with and without the valve end cap. (Note: The installation instruction state explicitly that the end cap should be used !)

Test procedure:

The sample was laid in the testing chamber, which was then evacuated to a pressure of 17 hPa. The background concentration of the test gas (SF6) was determined, followed by a waiting period of 30 seconds before the second measurement was carried out. The change in concentration is a clear indication of the total leak rate of the sample. The testing chamber has a volume of 13 litres. An LTS 311 V, S/N: 05107 was used. The simulation apparatus was calibrated with a pulse leak module.


Measurement of the total leak rate:

Types SSB/SSB2:

  1. Total leak rate directly after inflation of the sample (< 10 min)
  2. Total leak rate after 25 h


Measurement result:

(average of 4 single measurements)


Measurement No. 1
L [mbarl/s]

Measurement No. 2
L [mbarl/s]


< 2,3 x 10-8

< 2,3 x 10-8


< 2,3 x 10-8

< 2,3 x 10-8

The total leak rate for samples A and B was below the detection limit: L = 2,5 x 10-8 mbarl/s (corresponding to 0.73 mbarl/ year)