Annealing process of pharmaceutical glass bottles

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Taian Youlyy Industrial Co., LTD., the introduction of automatic bottle machine and energy-saving, environmental protection annealing furnace, with the online inspection system, to ensure the stabilit

Annealing process of pharmaceutical glass bottles


Each medicinal glass bottle has to undergo annealing, the role of annealing is to eliminate or reduce the thermal stress of the glass bottle to the allowable value of heat treatment process, after annealing, in the case of extreme cold and extreme heat, not easy to break. Annealing of glass bottles is to eliminate and reduce stress. Glass bottles undergo intense and uneven temperature changes during the production process, resulting in thermal stress of glass products. This thermal stress will reduce the strength and thermal stability of glass bottles, and even lead to the self-cracking of glass bottles.


One, the stress of medicinal glass bottle


      The stresses in glass are generally divided into three categories, namely thermal stress, mechanical stress and structural stress.


      1. Thermal stress: the stress caused by temperature difference in glass products is called thermal stress, which can be divided into temporary stress and permanent stress according to its existence.

      (1) temporary stress: the thermal stress generated when the glass undergoes an uneven temperature change under the strain point exists with the existence of the temperature gradient, and the stress that disappears with the disappearance of the temperature gradient is called temporary stress.

      (2) durable stress: the thermal stress generated when the glass undergoes an uneven temperature change below the strain point exists with the temperature gradient. When the stable gradient of the glass disappears, the residual thermal stress is called the durable stress.


      2. Mechanical stress: refers to the stress caused by external forces in the glass bottle. When the external forces are removed, the mechanical stress disappears immediately.


      3. structural stress: the glass because of the chemical composition of the uneven structure caused by the uneven stress on the structure is called structural stress, it belongs to the permanent stress, and the stress caused by the inherent structure of the glass is not eliminated, there are stones, stripes and homogenization of the glass will cause structural stress.


Two, annealing of pharmaceutical glass bottles


      In order to eliminate the persistent stress in the glass, the glass should be heated to a certain temperature near the transition temperature of the glass for heat preservation and equipping, so that the stress relaxation can eliminate the structural gradient caused by the temperature gradient of each part. This equipping temperature is called annealing stability. The annealing of glass products is generally divided into four stages.


      (1) the process from stable heating into furnace to stable annealing is called heating stage.


      (2) to maintain some time after the annealing stability, so that all parts of the glass bottle stable and uniform, so that the stress as far as possible to eliminate, known as the heat preservation stage.


      (3) the stage from stable annealing and slow cooling to stable annealing is called slow heating stage.


      (4) stable cooling from low annealing to fast cooling at room temperature.


Taian Youlyy Industrial Co., LTD., the introduction of automatic bottle machine and energy-saving, environmental protection annealing furnace, with the online inspection system, to ensure the stability and reliability of product quality, and win the majority of customers recognized and trusted.