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The Glass
DURAN® is a special borosilicate glass of the first hydrolytic class. Its invention was one of Otto Schott’s great achievements. Laboratory and chemical plant technology would be unthinkable without DURAN tubing, capillary and rod. They are the basis for custom-made solutions to specific problems.

The Advantages
Products made from DURAN are well-known for their stability and pressure resistance, good workability and high thermal shock resistance. DURAN has a very low rate of thermal expansion which makes it an excellent material for laboratory glassware and for use in large-scale technological plants in the chemical apparatus industry. Products made from DURAN are resistant to corrosion and remain absolutely neutral, even to aggressive chemicals, in nearly all fields of chemistry. This gives them a great advantage over other materials. Borosilicate glass is extremely resistant to water, acids, salt solutions, organic substances and halogens. Tubing, capillary and rod of DURAN also have a high alkali resistance. For physical and chemical properties.

The large range of tubing, capillary and rod provides a very high level of precision in all dimensions. These products are also available in the form of prestressed components for use in demanding conditions.

The Quality
As with every Schott-Rohrglas product, DURAN tubing, capillary and rod are manufactured using the latest technology. DURAN products correspond to the internationally acknowledged borosilicate glass type 3.3 (DIN ISO 3585). All stages of production are electronically controlled and backed up by a complete Quality Control System according to DIN ISO 9001 and certified by TUV Cert.

Further Processing
There is a wide range of fields of application for DURAN tubing, capillary and rod.

The main fields of use are in the laboratory and chemical sector. This covers products ranging from a simple test tube to filtering apparatus, and also includes an infinite variety of cooling, distillation and rectification plants.


The Manufacturer
Schott-Rohrglas produces special glass tubing, capillary and rod in a wide range of dimensions for a large variety of applications. Schott-Rohrglas is one of the leading manufacturers of special glass tubing world-wide with an annual production of over 50,000 metric tons and produces special glass tubing for processors all over the world using the very latest melting and production processes. Schott-Rohrglas GmbH is a member of the Schott Group.

Physical Data
Medium coefficient of linear expansion a201300 acc. to DIN 52328 3.3 10-6 K-1
Transformation temperature Tg 525 °C
Viscosity temperatures (dPa.s):    
      1013 upper annealing temperature
560 °C
      1076 softening point
820 °C
      104 working temperature 1260 °C
Maximum short-time working temperature 500 °C
Density p 2.23 g/cm3
Modulus of elasticity E 64 103 N/mm2
Poisson's ratio µ 0.20 1
Thermal conductivity Àw at 90°C 1 .2 W/m . K
Temperature for electrical resistance of 108 ohms . cm (DIN 52326)tk 100 250 °C
Electrical volume resistance logarithm (ohms . cm)
    
      at 250°C
8  
      at 350°C 6.5  
Dielectric properties (1 MHz, 25°C)
    
      Dielectric figure ~
4.6 1
      Dielectric loss factor tan ~
3.7 10-4
Refractiveindex(À = 587.6nm)nd
 1.473 1
Stress-optical constant (DIN 52314) K 4.0 10-6 mm2/N

Pressure Resistance

Calculation of pressure resistance (p) for a given Wall Thickness (WI)
and a given Outside Diameter (OD):

 dddd
Calculation of the Wall Thickness (‘NT) at a given pressure resistance (P) and Outside Diameter (OD):
 1
Resistance parameter for DURAN borosilicate glass 3.3: K/S = 7N/mm2 as per DIN EN
1595 Standard Draft: Pressure Apparatus made from Borosilicate Glass 3.3: General
Principles for Calculation, Production and Inspection

Pressure Resistance (p) can be impaired,for example, by the following:

  • Difference in temperature between inside and outside wall
  • Surface Quality
  • End Finish
  • Observance of Conditions of Installation as per Pressure Vessel Regulations
  • Tubing Length

Other points to be considered:

  • AD leaflet N 4, edition 9.83
  • Pressure Vessels made from Glass, with encl.1, edition 6.85
  • Assessment of Faults in Pressure Vessels made from Glass - AD leaflet B 1, edition 6.86
  • Cylindrical and Spherical Shells under Interior Pressure