Annealing process of pharmaceutical glass bottles

 Each medicinal glass bottle is annealed, the role of annealing is to eliminate or reduce the thermal stress of the glass bottle to the allowable value of the heat treatment process, after annealing, it is not easy to rest in extreme cold and heat. Annealing of glass bottles is to eliminate and reduce the stress. Glass bottles undergo drastic and uneven temperature changes during the manufacturing process, which leads to thermal stresses in the glass product. This thermal stress can reduce the strength and thermal stability of the glass bottle, and even lead to self-cracking of the glass bottle.

 

 

Pharmaceutical glass bottles 

Stress in glass is generally divided into three categories, namely thermal stress, mechanical stress and structural stress.

 

1. thermal stress: glass products due to temperature differences in the stress called thermal stress, according to its existence can be divided into temporary stress and permanent stress.

(1) temporary stress: the thermal stress generated when the glass under the strain point of uneven temperature changes, with the presence of temperature gradient, with the disappearance of the temperature gradient and the disappearance of the stress is called temporary stress.

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

2. mechanical stress: refers to the stress generated by external forces in the glass bottle. When the external force is removed, the mechanical stress disappears immediately.

3. Structural stress: glass due to structural inhomogeneous stress caused by the chemical composition is called structural stress, which is a permanent stress, the stress caused by the inherent structure of the glass is not eliminated, there are stones, stripes and homogeneous glass will cause structural stress.

 

Annealing of pharmaceutical glass bottles

In order to eliminate the continuous stress in the glass, the glass should be heated to a certain temperature close to the glass transition temperature for insulation and equipment, so that stress relaxation can eliminate the structural gradient caused by the temperature gradient of the layers. Part. The equipment temperature is called annealing stability. Annealing of glass products is generally divided into four stages.

 

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

(2) After annealing to maintain a period of stability, so that all parts of the glass bottle stable and uniform, so that the stress is eliminated as far as possible, known as the holding phase.

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

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

 

Hebei Xiangyi International Trading Co., Ltd, introduces fully automatic bottle making machine and energy-saving and environment-friendly annealing furnace, equipped with online testing system to ensure the stability and reliability of product quality and win the recognition and trust of our customers.