Concrete Weight Coating (CWC) plant

Additional weight to the pipe

The concrete weight coating of pipes is carried out when the pipeline must be laid sub-sea or passes a lake or river crossing. The major goal is to give the pipe additional weight (negative buoyancy) to prevent floating or displacement of the pipeline, as well as to provide mechanical protection. The concrete consists of a mixture of iron-ore, sand and cement with reinforcement wire and can be prepared with a specific weight varying roughly from 2200 – 3500 kg/m³. The application procedure for concrete generally involves impingement (blast spraying) or wrapping. For reinforcement, either prefabricated cages or a special wire mesh can be used. The cages are placed over the pipe prior to the coating. The wire mesh is applied as a wrap during the application of the concrete.

Plant configurations

Selmers provides plants for the application of concrete in various setups that are usually determined by site conditions and the required operational speed. Possible plant configurations are, for example:

  • coating pipe-by-pipe, in which each pipe is placed on carts and passes along the applicator
  • coating pipe-by-pipe, in which the applicator passes along the pipe
  • continuous coating, in which pipes pass the applicator in one endless string (high speed)

Plant setup

In addition to the required concrete mixing plant (batch or continuous mixing type), a plant setup generally includes:

  • incoming pipe holiday inspection
  • pre- and post-weighing scales
  • anode application equipment
  • curing promotion facilities such as steam chambers, foil wraps, compound sprays, and so on
  • pipe handling carts
  • pipe end finishing and touch-up equipment