Fused Silica Products for Technical Lamps

Quartz glass or fused silica is an irreplaceable material for many technical lamps. Learn more about how to find the best quartz glass or fused silica for your technical lamp application.

Quartz glass is the purest form of glass. It consists only of Silicon and Oxygen. Due to this unique chemical composition (single component glass) and the high purity – at Heraeus Conamic min. 99,999% SiO2 purity – quartz glass has excellent technical properties. In particular, the wide transmission spectrum from the ultraviolet, visible to infrared range (depending on grade between 160nm up to 4500nm) makes quartz glass an irreplaceable material for many technical lamps.

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Fusion Processes for Technical Lamp Tubes

Heraeus is using different fusion methods for the manufacture of technical lamp tubes. In the following you find a short introduction to the methods:

Production Methods for Lamp Tubes

Heraeus is using different production methods for tubes manufacturing. In the following you find the differences methods:

  • Single Step Tubing
    The pulling of tubing directly from the melt is the most cost efficient production process. It is available only for electric fused quartz. The outlet of the crucible is ring shaped and the size of the forming tool determines the available dimensions of tubing (outer diameter, wall thickness). Because a change of the forming tool is not possible once the process started, the range of tube sizes per run is limited. A large amount of tubes must be drawn in order to justify using this process. Tubes produced in the single step process have tight tolerances and are most economic.
  • Multi Step Tubing:
    In this process a pre-form (usually a cylinder) is locally heated and redrawn into tubing. The cylinder is either formed directly or an ingot is reshaped into a cylinder. Because the reforming of glass is independent on the actual production route of the quartz glass, multistep tubing is available in electric and flame fused quartz as well as synthetic fused silica. Furthermore, the additional process-steps homogenize the material usually resulting in a lower bubble content. The available finished sizes depend solely on the size of the starting cylinder. The advantage of the multistep process is the high flexibility regarding starting material and finished sizes, as well as a relatively small batch size.

More information about tubes for lamp applications

Material Selection Guide for Technical Lamp Applications

Heraeus offers many different quartz grades under various trademarks. The following table details these material grades and can offer guidance on which grades are suitable for specific applications.

++ = fitting // + = fitting to some extent


The basic grade for high-efficiency technical lamps

Purasil® V

Longlasting efficient synthetic fused silica for UV water and air treatment.


High purity synthetic fused silica for applications in the photonics area.


For long lasting and robust technical lamp applications.

Tools and Services

In the selection process for the most suitable fused silica grade the transmission performance is among the first criteria. Please check our transmission calculator. As an additional service, we offer the possibility to search our portfolio for existing part numbers.

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