Plastic welding is the joining method used for welding and fabrication of plastic pipes. There are more than 10 different methods of plastic welding, each with their unique advantages and specifications. Depending on the type of pipes and the industry they are used in, the relevant technique can be selected.
Where is plastic welding used?
Plastic welding is applied wherever plastic pipes are being used. Water treatment plants and water utilities are the biggest consumers of plastic pipes. The chemical process industry and microelectronics are the other biggest consumers of plastic pipes. Building construction and gas utilities as well as the marine industry are some of the other major consumers of plastic pipes.
Water treatment plants
Water treatment plants are responsible for supplying drinking water and industrial process water as well as managing sewage plants and waste water generated from households and industries. They often need to meet stringent regulations regarding the high quality of water produced in the water treatment process.
The types of plastic pipes that are most commonly used in water treatment are polyvinyl chloride (PVC) and chlorinated polyvinyl chloride (CPVC), which are more flexible and heat resistant compared to PVC pipes.
Butt fusion, electrofusion and socket fusion are the common welding techniques used in welding of these pipelines.
Chemical process industry
The activities related to extraction of natural resources and the conversion of them to basic chemical products is called the chemical process industry. The harsh environment of chemical plants and the strict safety regulations with regards to health hazards as well as environment standards compliance call for secure and efficient equipment for chemical handling. Plastic pipes are the most efficient option that can ensure high quality components, durable materials and precise process control.
From production of petrochemicals and fertilisers, galvanisation and production of paint, batteries or glass, to pulp and paper, starch, yeast and sugar, cosmetic and detergents and the textile industry, PVC pipes are used in factories for their lightweight, modularity of installation and long lasting life in aggressive environments.
Production of semiconductors, photovoltaics, LEDs and storage media all fall under the microelectronics industry, which is one of the major consumers of plastic pipelines. In this industry, water with high purity level is required. The minerals in the treated water can cause some chemical reactions in contact with metal pipes that consequently reduce the purity level of the water. That’s why plastic pipes are the better option. In order to maximise the level of purity of the water and minimise the level of impurities created during the welding process, infrared fusion is the technique used in welding of PVC pipes. Infrared fusion is a type of butt fusion but, because of the technology used in the welding, the pipe and the heated plate don’t touch so the heat is being transferred by heat wavelengths. Consequently, the purity of the material at the join of the pipe is maintained. There will be no foreign material such as minerals transferred onto the joining area that could affect the quality of the water.
Modern living calls for comfort, hygiene and sustainability. Plumbing in buildings from hotels and hospitals to commercial or residential buildings is a vital element and having a proper pipeline system is a crucial factor for consideration. Nowadays, the most popular type of pipe used in buildings is polypropylene random copolymer (PPR). In the past, for building water pipes, acrylonitrile butadiene styrene (ABS) and polyvinyl chloride (PVC) pipes were mostly used. But because of the tendency for leakage or damage to the product, the industry switched to PPR pipes, which are a better alternative.
All these pipelines can be built using butt fusion, socket fusion as well as electrofusion welding techniques.
Gas has been the most dependable form of energy over the past decades and it has been distributed through a network of buried pipes to homes and industries.
All gas transportation lines, distribution lines as well as service lines and house connections utilise plastic pipes as a safe and durable alternative to metal pipes. Polyethylene (PE) is the most common material used in these pipelines and butt fusion and electrofusion are the joining techniques utilised.
Ships and platforms are at high risk of corrosion as they are in constant contact with sea water. Plastic pipes not only minimise the maintenance time and increase productivity, they are also up to 5 times lighter than metal pipes and offer a major advantage for marine use compared to metal pipes.
In the past, metal was the primary type of pipe that was being used in different industries. However, there have always been some limitations with metal pipes. Metal gets corroded and not only causes defects, but can also impact the purity of the water that is flowing inside the pipe. Another factor that could affect the metal pipes is the soil movement which, over time, can cause fatigue damage to the rigid metal pipes. However, plastic components have more flexibility in comparison and this helps with adapting to the soil condition. The level of acidity or alkaline in the soil where the pipeline is laid is another factor that can influence the choice of pipe material.
TWI, in collaboration with George Fischer, offers training and solutions related to plastic welding and pipelines. For more information about our training courses visit our website here and to learn more about George Fisher solutions, visit their website here.