Clear Glass Tube, Glass Processing Plant, Big Size Tube Making
Process
1. Brief introduction
Glass is a special amorphous inorganic nonmetallic material. The
main component is silicate, a non-crystalline solid with an
irregular structure.
Glass melting is the most important process in glass production, it
is a forming process where the batched materials form a qualified
liquid evenly with no bubbles under high temperature heating.
At present, most of the tube glass production line mainly adopts
horizontal stretching Danner process and Vello process.
Physicochemical changes in each glass melting stage:
In this stage, the components of batched materials will produce a
physicochemical solid phase reaction during heating process, in
which the gaseous products will be released from the batched
materials and produce a new opacity sinter ultimately, which is
formed by silicate and SiO2.
In this stage, the sinter will be melting and the silicate and SiO2
in sinter will change to flint glass liquid with a plenty of
bubbles. However, its chemical components and character are not
even.
The glass liquid is continuously heated, and its viscosity is
reduced with plenty of gaseous sundries released, which should
eliminate the visible bubbles with the pool of liquid.
The glass liquid is kept at high temperature for a long time, the
ripple eliminates by diffused function and homogenizes as a whole.
The temperature of homogenization can be lower than the clearing
stage.
2. Forming process
The glass liquid flows out from the furnace through the throat,
goes into the rotating cylinder, the glass liquid will form a
tubular type under a rotating speed of the cylinder. The tubular
shape will be stretched and form a glass tube via graphite guide
roller by Danner machine.
The glass liquid flows out from the throat, and goes into a
heat-resistance alloy pipe, the glass liquid will form into a tube
under the function of compressed air.
3. Application of tube glass
| Item | Application |
| 1 | Biological medicine |
| 2 | Glass instrument |
| 3 | Solar |
| 4 | Lighting |
| 5 | Chemical |
| 6 | Nuclear |
| 7 | Electric glass |
| 8 | Others |
The optimal choice used for pharmaceutical glass tube must be
neutral borosilicate glass tubes.
General paramter of borosilicate glass tube:
| Item | Description |
| Density | 2.23 g/cm3 |
| Hardness | >7 |
| Modulus of elasticity | 63·103N·mm-2 |
| Tensile strength | 4.8x107pa(N/M2) |
| Compressive strength | (0-300) 3.3±0.1×10-6K-1 |
| Thermal conductivity | 1.2W·m-1·k-1 |
| Softening point | 820±10°C |
| Strain point | 516±10°C |
