Pipe coating plants
Selmers manufactures coating plants for many types of coatings, mainly for anti-corrosion-, insulation-, flow efficiency- and weight increase purposes. Just like as with the individual blasting machines, pipe coating plants are also available for many set-ups: for internal & external applications, small & large diameter, low & high capacities, continuous or one-shift operation.
Selmers distinguishes herself in the approach towards plant design, meaning that Selmers looks further than just the operation of the plant itself. In the design, special attention is given to:
- flexibility and ease of operation
- sufficient possibilities to incorporate future plant expansion
- easy plant foundation
- quick change over times to other diameters
- design with reasonable over-dimensioning
Other focus points in the design are affordability, use of standard and widely available components, efficiency in operation and reliability of the equipment. Selmers' engineers put a lot of effort in maintaining these focus points for which they have the availability of 3-dimensional CAD design facilities, giving the construction engineer an optimum feeling with his design.
The following is a selection of the most common pipe coating plant equipment in the program of Selmers, although variants on this selection and other type of coating applications are also well possible. Please contact us for specific questions or enquiries you have.
External multi layer PE and/or PP coating
In the multi-layer coating process pipes are blast cleaned and covered with a composed coating of three or more individual layers. Usually the first layer is a fusion bonded epoxy coating of 100 – 200 microns thickness, which is the actual anti-corrosion layer. On top of the epoxy an adhesive layer of 250 – 350 microns is applied which acts as the bond layer between the epoxy and the top layer(s). The top layer usually consists of 2 – 4 mm PE or PP and provides the mechanical protection to the pipe. In some cases foamed PP is added in extra intermediate layer(s) as an insulation coating for heated transport lines.
In the picture the two main types of coating lines are presented. One is for the side extrusion process (pipes rotate while top coating is wrapped around the pipe). The other is for cross-head extrusion (pipes do not rotate and coating is ‘pulled’ as a sleeve around the pipe).
These plants can be manufactured for virtually any capacity and pipe size and can be fitted with all thinkable add-ons such as:
- Internal dust removal equipment
- Extra surface treatment equipment (flush wash, acid wash, chromate wash)
- Mechanised pipe handling systems (pipe transfer cars, walking beams, pipe push conveyors, chain transporters)
- Pipe end cleaners
- Granules transport & heating system
- Pipe data collection and filing
- Automatic coating thickness measurement
- Water processing plant
- QC laboratory
A unique capability of Selmers is that the extruders required for the multi-layer coating plants are fully designed and manufactured by themselves and hence specially equipped for pipe coating applications, whereas 'buy-out' extruders would be more general purpose types not specifically designed for pipe coating. This own design of Selmers has been very successful and extruders ranging from 100 up to 2500 kg/h are nowadays in use on world wide pipe coating plant locations.
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Fusion Bonded Epoxy coating
Fusion Bonded Epoxy (FBE) application plants have a lot in common with the 3-Layer PE coating plants. The main difference is the absence of extruders, a shorter cooling section and normally the absence of pipe end brush cleaners for the cut back. FBE can be applied in one layer (normally 300 – 500 microns) or in a double layer, in which the top layer provides extra mechanical strength, a rough surface (to allow easier application of a concrete top coat) or to provide extra resistance against chemical or soil attacks.
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Internal anti-corrosion / Flow-efficiency lining
For the transmission of dry-gas, sour gas, potable water, sewage or oil, it is often required to apply either a flow-efficiency lining or an anti-corrosion lining inside the pipe. Typical for internal lining plants is that pipes are processed in a one by one sequence in separate stations, of which the grit blasting and lining station are the core of the process.
Depending on the pipe diameter, grit blasting is either accomplished by the air blast method or by a blast turbine. The lining is done by means of airless liquid spray coats (cold- or hot applied) or by Fusion Bonded Epoxy (FBE).
The design of Selmers' lining plants is very flexible in set-up and allows for a variety of equipment configurations, depending on the type of operation, lining specifications, ambient temperatures and available space. As in the internal lining process (in comparision to the external coating process), each pipe is processed separately, special attention must be given to efficient pipe handling and positioning of pipe enclosure cabins. This is realised by integrating or making available a high degree of automation as well as by making use of pipe handling devices such as transport cars, pipe push conveyors, walking beams, etc.
In addition to the core equipment (blasting and lining) the following stations can be added to the plant:
- internal wash
- pre-heating
- pipe-end tape masking / de-masking
- paint curing ovens (for cold areas and/or high production plants)
- holiday detection stations
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Concrete weight coating & cement lining
Concrete weight coating
The concrete weight coating of pipes is executed when the pipeline needs to be laid sub-sea or passes a lake or river crossing. The major goal is to give the pipe additional weight in order to prevent floating or displacement of the pipeline. The concrete consists of a mixture of iron-ore and sand with reinforcement wire and can be prepared with a specific weight varying roughly from 2200 – 3500 kg/m3. The application procedure for concrete is generally by impingement (blast spraying) or wrapping.
For reinforcement either prefabricated cages can be used or a special wire mesh. The cages are put over the pipe prior to the coating. The wire mesh is applied as a wrap during the application of the concrete.
Selmers provides plants for the application of concrete in various set-ups that are mostly determined by site conditions and the required operational speed. Possible plant configurations are for instance:
- coating pipe by pipe where each pipe is put on buggies and passes along the applicator
- coating pipe by pipe where the applicator passes along the pipe
- continuous coating, where pipes pass the applicator in one endless string (high speed)
Besides the required concrete mixing plant (usually batch type) a plant set-up generally includes:
- pre & post weighing scales
- anode application equipment
- curing promotion facilities such as steam chambers, foil wraps, compound sprays, etc.
- pipe handling buggies
- pipe end finishing & touch-up equipment
Cement-Mortar coating & lining (CM)
Another application of concrete, or in most cases cement-mortar, is for the lining of pipes carrying potable water or for sewage. The systems which Selmers manufactures for this application are versatile and can basically be divided into two groups:
- factory applied (usually for new and not so large diameter pipe)
- in-situ applied (usually for rehabilitation work or in case of very large pipes)
For factory applied linings, Selmers has all the required equipment in her supply program, such as the high speed pipe spinning tables – by belt or by wheels – as well as the CM applicator – by centrifuge or by pouring – as well as the CM batching plant pipe handling equipment.
For in-situ applied linings, Selmers has developed a buggy applicator in which a remote controlled or operator controlled machine is sent into the buried pipe to apply the CM-lining. Prior to this process the pipeline is cleaned, for which Selmers' also supplies the necessary equipment. For small pipe diameters the equipment is fitted with a camera. The CM is fed to the applicator buggy by means of a long hose or by a shuttle buggy bringing in batches of CM.
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Other coating plants
Besides the plants as listed in this section, there are various other plants available for instance for:
- Polyurethane (PUR) anti-corrosion coating
- Coal tar / Bitumen enamel anti-corrosion coating
- Heat insulation by PUR foam (district heating systems / hot oil transmission lines)
- Anti-corrosion tape application plants
Please contact Selmers for your specific enquiries or questions about these plants. |