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Pipe and sewer rehabilitation

Internal pipe seals

Description of the WECO process

1. Standard: DN 600 to 4,000 mm for walk-in pipes and

Internal pipe seals are used to seal partial leaks mainly on pipe joints.

Elements of the sealing system:

  • Rubber sleeve with sealing lips
  • At least 2 (open) Tension bands
  • Accessories for tightening the tension bands are sheets of stainless steel (packing plates) and spacers (adjusting pieces)

The rubber sleeve is laid and positioned from inside of the pipe over the leak (pipe joint, crack or other leakage) in a way that the leaking area is located between the two sealing lips.
Both tension bands will be placed in the corresponding grooves of the rubber sleeve. Underneath 

these grooves the sealing lips are placed.
With the help of a hydraulic installation tool the tension bands and thus too the sealing lips will be

pressed on inside pipe wall. By the pressing process the gap of the open tension band expands. These

gap will be closed by using of a corresponding adjusting piece after reaching the needed pressure force.

Due to the special physical characteristics, the rubber sleeve material ensures a safe and
permanent sealing.

This technology is used for the rehabilitation of pipes for gas, drinking water and waste water and of industrial pipes.

2. Liner-end seal: DN 200 to 600 mm for non-walkable pipes and sewers.

For end sealing of pipes and sewers previously renewed with CIP liners, appropriate
seals with a diameter of DN 200 or higher can be supplied.
For larger diameter differences between CIP liner and old pipe, conical seals are available.

3. Special WECO seals: 

  • "large" - for seals larger than DN 4,000 mm;
  • “Infiltration” - for sealing against pressing water from outside,
  • "Non-circular” - for other pipe profiles (e.g. elliptic of egg-shape profiles),
  • "Large width” - for pipe defects width length from 150 to 350mm,
  • Larger defects (longitudinal cracks, closing of pipe outlets, etc.) can be sealed with the help of a rubber hose. A WECO seal will be installed at each end of the rubber hose.

Assembly instructions

General instructions for the installation of "Standard" internal pipe seals with one-piece tenseion bands.

1. Installation preparation of the sealing surface and insertion of the rubber sleeve:

  • Smoothing of sharp edges or uneveness´s
  • If necessary, re-profiling with suitable material
  • Cleaning the sealing surface
  • If necessary, apply lubricant to the sealing surface
  • Cover the leakage by inserting the rubber sleeve

2. Insert the rubber sleeve

  • Place the sealing lips of the rubber sleeve on the prepared and cleaned surfaces
  • Align rubber sleeve at right angles to pipe axis
  • Wrinkle-free installation

3. Insert tension bands:

  • Insert the bands into the corresponding grooves of the rubber sleeve
  • Position the lock pieces of the open tension bands with packing plates in 5 or 7 o’clock position (opposite the vulcanization seam of the rubber sleeve)

4. Tighten the tension bands:

  • tightening the tension bands with the help of a hydraulic installation tool - thus the gap of the open bands will be expand
  • Inserting an adjusting piece (spacer) in a suitable length between the lock pieces of the open tension band

5. Pressure test:

  • Overall position (from manhole to manhole)
  • Single pressure test with a valve or sleeve testing device

Tools and installation aids for the installation of internal pipe seals


  • Locksmith tools (standard equipment)
  • Special hydraulic installation tool for tensioning the tension bands

Installation aid material

  • Abrasives and tools to smooth the sealing surface areas in particular on steel and cast-iron pipes
  • if necessary materials for re-profiling sealing surfaces (e.g. mortar) in particular on concrete pipes
  • if necessary lubricant as an installation aid to improve the sliding of the rubber sleeve material on the pipe wall when tightening the tension bands
  • Compressed air in case of using special valves for the pressure test

Training for the correct installation of weco seals and consulting


The production of WECO Internal Pipe Seals to a consistently high quality standard is a prerequisite 

for a successful and durable pipe and sewer sealing. This is the responsibility of our company PBT.

The second important requirement is the quality of the installation process.

However, past experience has shown that foreign customers in particular prefer to carry out the

installation themselves. Of course, this is possible and useful in many cases to save money.

Even if the installation procedure does not appear to be complicated according to the general

installation description and in principle is not complicated, there are a large number of influencing

factors which can be a great importance in the preparation and execution of the installation and

must be taken into account.

For the benefit of our customers and our own safety, we therefore attach great importance to the

fact that the installation personnel are qualified for the installation of internal pipe seals.

The installation training can optionally be performed

  • on site at the customer´s (recommendable and very effective on a real project) or
  • in our company


WECO internal seals have been used since the 1960's and were originally developed to seal walk-in

pipes for the gas and water media.

In the following decades of development of the pipe networks and pipe materials as well as the

procedures for the pipe and sewer rehabilitation and the traffic loads also new requirements with

regard to the use of internal pipe seals arose again and again.

Due to the many years of experience of our employees and the same longstanding contact with our

customers, we have succeeded to meet the respective new requirements and to open up further 

application possibilities by modifying our standard internal pipe seals or developing new 

components, see process description 2. Liner-End-Seal and 3. Special Seals.

For a project-related consultation, we are available to every customer.

The more details we get about a current project, the more concrete and targeted the advice.