APG technology 1

APG technology is currently mainly used to produce medium voltage epoxy resin insulation products. The APG process can not only effectively improve production efficiency, but also has high quality and good dimensional stability. It is especially suitable for mass production of medium voltage epoxy resin insulation parts.

This article briefly introduces APG technology based on artistic principles, basic characteristics and manufacturing conditions. APG technology is currently mainly used to produce insulation products based on medium voltage epoxy resins, especially solid sealed terminals used in vacuum circuit breakers. The complex, thin-walled, multi-directional core-pulling products have more advantages. Nowadays, high-voltage switches at home and abroad are developing towards maintenance-free, compound, miniaturized, long-life and high-performance systems. The use of APG technology to produce medium voltage insulation products also has significant technical advantages and broad development prospects. Therefore, in recent years, it has developed rapidly at home and abroad. Its products involve 5kV fixed and sealed poles, post insulators, insulators for live displays, contact boxes, separation sleeves, rotating shafts, vacuum cylinders for vacuum circuit breakers, basin-type insulators, and current Transformers and voltage transformers, etc.

APG is an automatic pressure gel based on liquid epoxy resin. It is developed on the basis of the vacuum casting process of epoxy resin. It is a pressure gel process (PG) technology. Pressure gel (PG) technology is a technology developed in 1957 by Ciba-Geigy of Switzerland. In the early 1970s, PG technology was further integrated to form an automatic pressure gel process technology.

The APG process includes three processes: pre-mixing, automatic gelation under pressure, and hardening after molding. Once the metal insert is installed in the mold, the temperature of the mold is preheated to 80 to 100°C higher than the temperature of the epoxy resin mixture, that is, to 140 to 160°C. Then through the pressure system of the APG equipment, the epoxy resin mixing system in the storage tank (which has been defoamed in a vacuum) is pressed into the mold cavity through the pipe, and the mixture of the epoxy resin and the high temperature mold wall of the mold quickly heats up exchange. Since the epoxy resin mixture near the mold wall reaches a high temperature state in a short time, the epoxy resin mixture quickly undergoes a curing reaction and gels near the mold wall and the gel. The curing shrinkage of the epoxy resin mixture is quickly rebuilt by the liquid epoxy resin mixture under pressure in the center of the mold cavity. Under the pressure in the storage tank, the epoxy resin mixture is continuously updated throughout the mold cavity to remove the gel in the epoxy resin mixture. The pressure in the entire system is not released until all the epoxy resin mixture in the entire cavity is gelled.