Solvent Grid Cloth and Solvent Free Grid Cloth
Grid fabrics are widely used in dry type transformers. Their main differences are:
1. raw materials are different. The glass yarn commonly used in solvent grid cloth is middle alkali yarn. The solvent free mesh cloth is generally used in alkali free yarn. The composition and ratio of the adhesive resin are different.
2. different production processes, there are solvent grid cloth in the production process of air environment in the ambient temperature impregnation of soluble resin in the oven after heating after curing, curable. The gaps in the mesh glass fiber yarns can not be completely filled with resin, but still remain part of the gap. The finished products still contain volatiles, and the production cycle is short. The process of solvent free mesh production was vacuumed and impregnated with non solvent resin at a certain temperature, and then heated and cured. The gap inside the grid glass fiber yarn is completely filled with resin and does not contain volatiles. The production cycle is long.
3. the use process is different. There are small pores in the wall of the pouring tube when the roasted grid of the oven is sticky and volatilization of the volatiles during the process of transformer production in the process of transformer production. The solventless grid cloth will not be in the process. The solventless grid cloth is suitable for interlayer insulation of the coil, and there is no placement under a certain electric field strength. The use of solvent free mesh can reduce the thickness of interlayer insulation, which is beneficial to the miniaturization of the coil. The solvent grid cloth is suitable for internal and external insulation of the coil.
4. different grades. Mesh cloth can be divided into “F, H” grade according to the temperature resistance of its impregnating resin, usually “F” grade. The grid has high mechanical strength at normal temperature and still has high mechanical strength at a certain temperature. It can ensure the safe operation of transformer and reactor under overload and high temperature.
5. distinguish between solvent grid cloth and solvent free mesh cloth. In the initial production process, solvent grid cloth is red, and solvent free mesh cloth is yellow or colorless. But with the change of market demand, the solvent free mesh cloth also produces red in batches. In order to distinguish red color from different colors, the product’s certificate and export list will be identified.