Canning containers are reusable, economical and convenient

Glass jars are widely used in the canning industry. Its advantages are stable properties, no chemical changes with food, and glass canned food has a small contact surface with metal, so it is not easy to react; the glass is transparent, and the contents in the jar can be seen, which is convenient for customers to choose. Purchase; empty cans can be reused, economical and convenient. Its disadvantages are that it is heavy, brittle and easy to break, and it is inconvenient to transport and carry; At present, glass jars are developing towards thin wall and high strength, and new bottle types are constantly coming out. The health departments of industrially developed countries have officially stipulated that infant food can only be used in glass jars.
The glass jar is made of quartz sand, soda ash and limestone in a certain proportion, melted at a high temperature of 1500°C, and then slowly cooled and formed. Glass jars of various volumes and shapes can be made by using different molds during cooling and forming. The composition of raw materials affects the properties and color of glass. In order to improve the thermal stability of glass jars and meet the needs of can production, it is generally necessary to go through another heating and annealing procedure. The production process of glass jars is: raw material grinding, sieving, batching, mixing, heating and melting, forming, annealing, and inspection.
Good-quality glass jars should be transparent, colorless or slightly cyan, have good chemical and thermal stability, and usually do not break under the conditions of heating and pressure sterilization. The mouth is round and flat, the bottom is flat, and the tank body must not have serious defects such as air bubbles, cracks, stone chips and streaks.
There are many forms of glass jars, but now the four-spin jar is the most used, followed by the roll-sealed victory jar. The key to the glass jar is the sealing part, including the metal jar lid and the glass jar mouth. Victory can is composed of tinplate or painted iron can lid, rubber ring and glass can body. It has good sealing performance and can withstand heat and pressure sterilization, but it is inconvenient to open and its shape needs to be improved. Its volume is 500mL. The four-spin can is composed of a can lid made of tinplate, a rubber or plastic gasket, and a glass jar with a threaded line on the neck. When the lid is tightened, the claws on the inside of the lid and the thread match each other to compress the gasket. That is to achieve the purpose of sealing.