BOROSIL® brand sintered glassware is used for the filtration of liquids and gases in the laboratory. It incorporates a porous glass disc as a filter media, which is non corrosive and reusable. It is also used for gas washing, dispersion and absorption.

Sintered disc is manufactured by crushing BOROSIL® brand glass, powdering, cleaning, separating into various mesh sizes and then fusing together in the form of a disc. The sintered disc is graded into 5 grades - G1, G2, G3, G4, and G5. The grades are classified by maximum pore size, which is obtained by measuring pressure at which the first air bubble breaks away from filter under certain conditions. The pressure differential is then used to calculate the equivalent capillary diameters in microns. The desired pore size is obtained by suitably controlling the grain size, firing time, temperature and the thickness of the disc. Each disc is tested and graded individually.

The pore diameters are reasonably uniform, which ensures required flow rate through the filter. The flow rate further depends on pressure differential between the two sides of the disc, free area of the disc, viscosity of the fluid being filtered, etc. Between different discs of same size and grade, there is a fair amount of uniformity in pore size and hence the results from two or more discs of the same size and grade will be uniform. This ensures reproducible analytical results.

The discs have maximum surface hardness and hence glass powder does not get scraped off during cleaning or with chemicals. Filters do not shed particles during usage.The discs are sealed to tubing without blocking the pores. Then they are annealed properly in automatically controlled lehrs.