Development of Micro-porous Glass & Conversion to Pilot Scale Production of Working Artefacts

Varian, Inc. was one of the largest manufacturers of scientific instruments and consumables for the scientific industry; they had offerings over the whole range of chemical analysis equipment, including Information Rich Detectors, Vacuum technology, GC and LC systems and columns.

At the Church Stretton site (formerly Polymer Laboratories) focus was on the manufacture and processing of polymeric products, notably polymer standards and particles for the chemical and pharmaceutical industry.

In the development and manufacture of their products, the company requires high levels of control and traceability in order to ensure the optimum level of quality and reliability.

The Challenge

Varian had employed a very specific porous glass membrane in a polymer processing/filtration step. The glass material displayed the desirable properties of chemical stability and closely controlled pore size. The sole supplier of this was based in Japan and had not developed the product to ideally suit Varian's requirements. Due to the relatively small volumes of material required, supply chain problems became evident. In addition, this supply did not give the company the possibility of modifying the material to suit new applications.

The glass material was determined to be a phase-separated alumino silicate. Phase-separated glasses are formulated to produce glass-in-glass phase separation. When suitably processed, this separation can result in a material having two phases with an interconnected or spinodal structure. This development of the structure determines the porosity of the porous glass following removal of one of the phases. In this case, a chemically stable glass with uniform pores of 1µm was required.

Varian approached Lucideon (then called Ceram) with a requirement for the supply of the porous glass material ultimately in a tubular form of specified dimensions. Furthermore, it was crucial that the interconnected porosity was of a specific and uniform size that could be adjusted to suit a range of requirements.

What We Delivered

Communications with Varian identified the generic type of glass required and the specifications for the end product. Ceram recommended that the development should be undertaken in two stages:

  1. Material development
  2. Pilot scale manufacture

A formulation was created at Ceram and glass samples produced for testing (fig 1.)

Testing of the glass showed that it had the potential to develop the required structure (fig 2).

Glass sample prior to pore formation and final pore structure (7µm L-R)

Ceram's experts were able to interpret the results with reference to the composition of the glass and make recommendations for improvements.

Following a review of the results Varian decided to go ahead with the preparation of the porous glass in a tubular form, thereby presenting Ceram with a new challenge. Glass tubes are usually made in large volumes in a very limited range of compositions and, while some tube makers will produce customized compositions, minimum volumes are measured in tonnes rather than the 50-70kg required.

Through Ceram's contacts in the glass industry, a glass producer with the necessary skills and flexibility to produce the glass in tubular form, and of the correct size, was located. The raw materials were obtained and blended by Ceram and delivered to the glass maker who was able to produce a quantity of the glass in the form of tubes in the dimensions required by Varian for their pilot scale developments. The tubes were supplied to Varian for use in pilot scale studies and the development of new scientific equipment.

Value to the Client

Ceram was able to interpret the data and create a material that developed the requisite properties. We were then able to assist further by facilitating a larger scale production of the glass in a tubular format of the correct size. In this way, Ceram was able to support Varian in taking a development from feasibility study to pilot scale completion in a short timescale.

Throughout the process Ceram experts were able to develop and modify the materials and process and offer advice for future improvements.

Varian has taken the glass components and applied them in their production and development of scientific equipment.

Mr Graham Margetts (R&D Manager) of Varian stated:

"For Varian, access to the specialized skills and experience within Ceram was invaluable enabling Varian to gain strategic control of a crucial component of their chemical processing. In-house development would have been extremely difficult to justify; the knowledge and expertise required for such a program did not exist within the company."

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