Installation Precautions for UHMWPE Sheets

Ultra-high molecular weight polyethylene (UHMWPE) as a surface lubricating material has special wear resistance, extremely low friction coefficient, super impact resistance and excellent corrosion resistance, which are beyond the reach of many materials so far. With the popularization of the knowledge of ultra-high materials, it has attracted the attention of domestic design units and users in recent years. As the lining material of material silos, raw coal silos, coal drop pipes and trough linings, it has gradually been widely promoted and used in power plants, steel mills, docks, mines and other industries.

Theoretically, the installed ultra-high molecular weight polyethylene liner has a service life of about 3-5 years. However, in actual situations, some liner panels often fall off and become damaged prematurely. So how can we avoid this phenomenon? A comprehensive explanation of the selection of uhmwpe liner sheet size, the form of caulking, the molding process, and the installation methods of different substrates is given:

1. Accurate selection of UHMWPE liner sheet size

Due to the different expansion coefficients of different substrate materials, the linear expansion coefficient of UHMWPE sheet is about 150T/℃, which is more than ten times that of steel plate and concrete. The size selection during installation is particularly necessary. Choosing large and complete plates can certainly reduce the generation of joints, but at the same time, due to the large temperature difference between day and night, the plates will produce normal expansion and contraction. This will cause tearing stress between the lining and the fixing bolts, accelerate the bolts from falling off, and cause the plate to fall off. In order to improve the service life, the editor recommends the use of plates with a size of less than 1 meter by 1 meter for design and installation to avoid the falling of bolts and plates due to excessive contraction and expansion of the sheets.

2. Reasonable form of mortar joints

Between plates and plates, there are two forms of mortar joints, horizontal and vertical, according to the direction of material flow. The longitudinal connection adopts the form of upper cover and lower slope of 45°, which is convenient for reducing the gap between the material flowing into the plate and the substrate, and causing extrusion and falling over time. The horizontal connection method adopts the method of not beveling between vertical joints, and adopts plane right-angle connection, and the gap at the joint is not more than 3mm. There should generally be no joints at the corners of the inclined surface and the vertical surface, and the lining plate is folded into the corresponding angle by bending.

3. Good raw materials and excellent production technology

Because the molding process and raw materials of each manufacturer are different, the quality of the products produced is also different. In terms of appearance, even professionals are not easy to distinguish. Therefore, it is particularly important to choose a manufacturer with good reputation. The rebound performance of polyethylene with a molecular weight between 4 million and 6 million is in the best state. It has both the highest wear resistance and the best impact resistance, and the best cost performance. In terms of molding, because the molecular structure of ultra-high molecular weight polyethylene is viscous and has poor fluidity, it is necessary to adopt a compression molding process, high temperature and high pressure cold extension to shape.

4. Installation requirements of base material

The quality of the base also affects the installation quality. The fit between the plate and the base is the closest. Especially if the base is made of concrete, the gap must not be too large. Therefore, it is necessary to treat the concrete surface and level it with cement before installation. The expansion screws in the installation area must be installed firmly to avoid falling off due to long-term material erosion and vibration.