Are there any engineering examples of plastic-lined pipes without flange connections in process pipelines?
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This post was last edited by wx_KhkO2 on 2025-6-4 21:40. It seems that there are now plastic-lined pipes and fittings in the market that use non-flange connection methods (such as threaded connections, clamp connections, etc.). However, in the standards for lined pipes, whether they are chemical industry standards or national standards, flange connection is the only type of connection mentioned. I wonder if there are any actual engineering examples of connection methods such as threaded connections and clamp connections being used in process pipes like process material pipes and exhaust pipes If there are any comments, what is the actual performance in use?
In current common engineering practices, plastic-lined pipes used for chemical applications such as process material pipelines and exhaust gas treatment pipelines are primarily connected using flanges. This is because: 1. **Standards and industry regulations specify and commonly adopt flange connections to ensure safety, leak prevention, and long-term stability** ； 2. The lining layer of lined pipes possesses a certain degree of flexibility, and only flange connections can effectively prevent damage to the lining layer or failures in sealing ； 3. Flange connections are easy to maintain and repair; they can be disassembled repeatedly, offering safety and reliability, making them suitable for industrial applications where stability and reliability are essential. The non-standard connection methods such as \"threaded connection\" or \"clamp connection\" that do exist in the market are usually used only in civil building water supply and drainage systems, general low-pressure transmission systems (such as ordinary water pipes, small-scale water supply systems, HVAC systems), or in environments with low corrosion. In typical process pipelines such as strict chemical production lines, acid and alkali material transportation systems, high-corrosivity medium transfer systems, and exhaust gas treatment pipelines, plastic-lined pipes connected by threading or clamping are not common, and there are few clearly defined and widely recognized successful engineering examples. In summary, although plastic-lined pipes and fittings in non-standard forms (such as threaded or clamp connections) are available on the market, it is still difficult to find mature, reliable, and widely recognized practical engineering examples for their use in actual industrial projects such as process material pipelines and exhaust gas pipelines. It is recommended to adopt a cautious approach and, in accordance with existing ** and industry standards, give priority to the use of flanged pipes. .
We are a professional manufacturer of fluorine-lined pipeline valves. At present, our company’s fluorine-lined pipelines use only one type of connection method, namely flange connection
Liner pipe connection methods such as socket-electrofusion welding and socket-adhesive bonding can be developed. Socket welding with electrofusion can be used in situations with high pressure; the PN16 grade is achievable ； The bonding using special adhesives can be applied in situations with low pressure; those with a pressure rating of up to PN10 are suitable for this purpose. Adhesives that cure through heat or light yield better results. These have significant advantages over flange connections in many aspects, and can replace flange connections in certain applications.