Plastic pipes for the transport of industrial fluid media, due to their unique plastic material molecular structure, make it in the field of industrial use relative to the metal material shows unparalleled superiority. The molecular chains of thermoplastics are combined with stronger inter-chain (sub-price) forces, PE Pipe Fitting Mould rather than the chemical bonds that are unique to the crosslinking system. Therefore, the separation of the molecular chain of the thermoplastic does not involve the destruction of the main valence bond. PE Pipe Fitting Mould The interaction between the solvent and the plastic is not fundamentally different from that of the solvent with the low molecular weight organic substance.
The process of absorbing or desorbing the fluid medium in a plastic is time dependent, subject to its solubility and diffusion coefficient, and some materials are staggering for a balanced time. Therefore, the ISO 4433 series of "Thermoplastic Tubes - Resistant to Liquid Chemicals - Classification "The standard sample (for the type of tensile test) made from the test material is taken from the pipe and the sample is completely immersed in the liquid chemical to be tested and subjected to a certain soaking cycle, depending on the time The change in the quality of the sample, the change in tensile properties (elastic modulus, PE Pipe Fitting Mould yield and fracture strength, yield and elongation at break) are used to measure the chemical resistance of a plastic pipe material to a fluid medium without stress.
The walls of thermoplastics pipes that transport industrial fluid media may have several phenomena at the same time: on the one hand, the tube wall absorbs liquid and / or precipitates the soluble component from the tube wall; on the other hand, the chemical reaction also causes the pipe The character has changed greatly. The internal and external stresses (such as temperature, pressure, wall thickness, etc.) of the pipe are different. PE Pipe Fitting Mould Therefore, it is important to design plastic pipelines to transport industrial media and to understand the interaction of plastic materials with a chemical medium. Plastic pipe standardization structure design and strength design is the premise of the manufacture and use of plastic pipes, PE Pipe Fitting Mould the fundamental task is to specify the working conditions, in order to ensure a number of years of service life, to correctly use the plastic pipe raw materials and grades, the structure of the pipeline size , Run the design and so on.
Pipeline application design factor CA is a value greater than 1, should be fully taken into account the fluid conditions, installation environment and fluid chemical properties and other factors, by the designer according to the various conditions of the pipeline to consider, PE Pipe Fitting Mould to ensure that the pipeline design Have reliable security. According to the experience and the actual use of the general selection between 1.3-4. For low pressure, room temperature, low concentration of acid, alkali, PE Pipe Fitting Mould salt can be selected between 1.3-1.5. For very warm or corrosive media should choose a higher application coefficient to ensure the necessary safety margin. PE Pipe Fitting Mould If the conditions are more complex or have a certain risk, PE Pipe Fitting Mould it should be careful not to use only a simple safety factor method for pipeline design, for safety reasons, should be used by the test method (ISO 4433) to obtain the basis of the pipeline material stress σB.
