Metafilter

Principle

• Mechanism is surface filtration

• In this, metal rings contain semicircular projections, which are arranged as a nest to form channels on the edges

• This channel offers resistance (strainer) to the flow of solids (coarse particles)

• The clear liquid is collected into receiver from the top

Construction

• Metafilter consists of a series of metal rings

• These are threaded so that a channel is formed on the edges

• It contains a grooved drainage column on which a series of metal rings are packed

• These rings are usually made up of stainless steel and have dimensions of about 15.0 mm internal diameter and 22.0 mm external diameter

• Each metal ring has a number of semicircular projections (0.8 mm in thickness) on one side of surface

• The projections are arranged as a nest to form channels on the edges

• These rings are tightened on the drainage column with a nut

• Metafilters are also known as edge filters

Diagram of metafilter

Working

For separation of fine particles, a bed of suitable materials such kieselguhr is first built up.

The pack of rings serves essentially as a base on which the true filter medium is supported.

Advantages

• Can be used under high pressures, without any danger of bursting the filter medium

• Running cost are low, as separate filter medium is not used

• Can be constructed from a material that can provide excellent resistance to corrosion and avoid contamination of sensitive products

• It is extremely versatile filter because fine as well as large both type of particles can be separated

• Removal of cake can be carried out by simply back- flushing with water

• Change over from one batch to another or one product to another is easy

• Sterile products can be handled

Uses

Meta filters can be used for -

· Clarification of syrups

· Filtration of injection solutions

· Clarification of insulin liquors

· Filtration of viscous liquids can be achieved by applying pressure

Metafilter - Pharmaceutical Engineering B. Pharm Third Semester PDF Notes