Design: cylindrical, with narrow tube
Filters made of borosilicate glass are suitable for various applications because of their excellent properties. Applications are pharmaceutical, biotechnology, medical, chemical and environmental. They are used from coarse liquid and gas distribution to bacteria filtering.
THOMAPOR®-borosilicate universal filters are exclusively made of borosilicate glass, without using other substances, such as binding agents which corresponds to DIN ISO 3585. They consist of pure glass grit.
The filter effect of a porous pad comprises screen effect and adsorption. If a filter should only act as a screen, its pores have to be smaller than the solid particles to be filtrated. The fluid volume to be put through is relatively small. Large flow volumes are achieved by use of a filter pad of which the filter effect is primarily based on adsorption. In this case, the filter pores can to be several times larger than the solid particles to be separated; e.g. for sterile filtration of air porous filter pads with pore sizes of 15 to 40 µm are used while the size of the particles to be retained (micro-organisms) is only 1/10 to 1/50 of the filter pore size. A sure adsorption can only be achieved with a very large inner surface of the filter body. If a filter pad is fritted of glass grit should get a large inner surface, the single granule already has to have a maximum large surface.
In this respect the THOMAPOR®-borosilicate universal filter program is an innovation. For production of the granules special crushing processes are used guaranteeing a splintery granule with a particularly large surface. This surface is again enlarged by a special treatment.
THOMAPOR®-borosilicate universal filters are manufactures as round plates in sizes of 5 to 120 mm diameter and are available in two designs:
Type: G: Ground to nominal diameter, edge non-fused
Type BG: Ground to nominal diameter and surface biplane, edge non-fused
The filter porosity is divided into 6 categories and lies between 10 and 500 µm, rendering the filters usable for all work in the chemical and pharmaceutical industry, in the laboratory and in industrial-scale plants.
The pore size indicated refers to the smallest size of particles to be retained during filtration. The porosity is determined by using the bubble pressure method according to Bechhold:
P 500, 250 - 500: Distribution of fluids and gases, supports for solid materials in flow systems
P 250, 160 - 250: Distribution of gases, distribution of gases in fluids with low gas pressure, filtration of coarse precipitations
P 160, 100 - 160: Coarse filtration, filtration of coarse precipitations, gas distribution in fluids, fluid distribution, coarse gas filter, extraction apparatuses for coarse material, supports for loose filter layers against gelatinous precipitations
P 100, 40 - 100: Preparative fine filtration, preparative work with crystalline precipitations, mercury filtration
P 40, 16 - 40: Analytical filtration, analytical work with medium fine precipitations, preparative work with fine precipitations, filtrations in cellulose chemistry, fine gas filters, extraction apparatuses for fine-granular material
P 16, 10 - 16: Analytical fine filtration, analytical work with very fine precipitations (e.g. BaSO4, Cu20), preparative work with corresponding fine precipitations, check-valve and stop valve for mercury