Glass tubing

Glass tubing are tubular, mainly cylinridcal, hollow-ware. Their special shape combined with the huge variety of glass types (like borosilicate, flint, aluminosilicate, soda lime, lead or quartz glass), allows to use glass tubing in many applications. For example, laboratory glassware, lighting applications , solar thermal systems and pharmaceutical packaging to name the largest.

In the past, scientists constructed their own laboratory apparatus prior to the ubiquity of interchangeable ground glass joints. Today, commercially available parts connected by ground glass joints are preferred; where specialized glassware are required, they are made to measure using commercially available glass tubes by specialist glassblowers. For example, a Schlenk line is made of two large glass tubes, connected by stopcocks and smaller glass tubes, which are further connected to plastic hoses.

Compared to other materials like plastics the importance of cylindrical half-finished products in glass is high. Main reasons are the difficulty associated with 3-d forming of glass in general. In order to create hollow objects from glass the cylinder shape is a natural starting material.

Cylindrical glass tubes have:

• the lowest surface area and most compact design

• highest mechanical strength against pressure and impact

• automated further processing due to symmetry.

Compared to moulded glass ware the process of tube drawing achieves:

• better optical clarity

• more homogeneous distribution of wall thickness

• higher precision or volume and geometry in general

Until the 19th century glass tubes were exclusively produced by mouth blowing, thus discontinuously manufactured from a batch or a glass melt. In 1912, E. Danner (Libbey Glass Company) developed the first continuous tube drawing process in the USA, which works in horizontal direction. In 1918 he received a patent. In 1929 a vertical drawing process was developed by L. Sanches-Vello in France.

Glass tubes are produced in various types of glass and in diameters ranging from a few millimeters to several centimeters. In most production processes, an "infinitely long" glass tube is drawn directly from the melt, from which approximately 1.5 m long pieces are chopped off after passing a roller track up to the drawing machine.

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Wikipedia