Construction glass. Concepts and terms !

Construction glass. Concepts and terms !

The composition of “construction” glass

Construction glass consists of the following “ingredients”:
* quartz (raw material, in the form of sand): 70-72%
* soda, carbonate and sulfate (reaction catalyst): about 14%
* lime in solid form (stabilizer): about 10%
* metal oxides – aluminum, magnesium (increasing the physical properties of glass, including resistance to atmospheric pollution)

Oxides of other metals may be included in the mass-painted construction glass.

Production of construction glass

Consider the production of construction glass by the float method, it consists of the following stages:

1. Preparation of raw materials

A mixture of raw components (where waste is added, broken glass to reduce the melting point temperature) is charged into the furnace and diluted with water to separate the necessary components from dirt.

2. Raw material melt

In the furnace , the glass production process goes through 3 main stages:
* melting (1.550 °C
• * purification – homogenization (the mass becomes homogeneous and gas bubbles are removed from it)
* temperature change (the melt is cooled to a viscous state, convenient for stretching through a tin bath)

3. Forming the glass surface

Liquid glass is poured onto the surface of a bath filled with molten tin, the temperature of which is about 1,000 ° C.

The bath is made in the form of a ribbon, the thickness of the tin is 6-7 mm. Due to the high viscosity of the glass, it does not mix with liquid tin, while ensuring a very smooth contact surface of both materials, which determines the smooth quality surface of the glass. The thickness of the future glass sheets is determined by the amount of molten glass poured into the bath.

4. Annealing of glass

After the tin bath, the already solid glass in the form of a ribbon passes through a cold tunnel called “lehr”. The temperature of the glass gradually decreases from 620 to 250 ° C. The cooling process continues until the condition of the glass allows it to be cut and processed.

5. Glass cutting

The cooled glass tape is cut on automatic tables into sheets of the desired size.

Construction glass. Types of glass

The following types of glass can be distinguished:

1. Transparent float glass

2. Mass-tinted glass

3. Reflective or sun-reflecting (K-hard-coated glass and I-soft-coated glass)

4. Energy-saving glass (selective glass)

5. Multifunctional glass (reflective + energy-saving glass)

6. Special glass (frosted, fire-resistant, patterned, protective…triplex)

Mechanical properties of glass:

* density: 2.5kg/m2

* pressure resistance: 1.000 N/mm2 (Mpa). That is, to crush 1 cm3 of glass, it is necessary to load it with a weight of 10 tons.

* resistance of glass to fracture. According to this parameter , the types of glass are distinguished:

– ordinary glass: 40 N/mm2 (Mpa)

– tempered glass: 120-200 N/mm2(Mpa) depending on thickness, edge treatment, presence of holes…

* elasticity: glass is a very elastic material, it is not subject to any deformation up to destruction. However, the glass is very fragile and instantly breaks when exposed to excessive external influences.

* thermal shock: Since glass has low thermal conductivity, uneven heating or cooling of the glass sheet leads to stress in the material (thermal shock). This may cause the glass to break.

When the construction glass is installed in the frame, its framed edges are closed from solar radiation. This can lead to a temperature difference in the glass, and to its destruction. The risk of thermal shock is reduced when a sunscreen heat-absorbing glass is used.

Special hardening of the glass against thermal shock allows you to withstand a temperature difference of 150-200 ° C.

The weight of the glass. The density of the glass is 2.5g/cm3. With such a density , the weight of 1 square meter of glass with a thickness of 5 mm is as follows:

100*100*0,5*2,5 =12.500 grams or 12.5 kg.