2. Meta filter
Meta Filter is simply a row of metal rings arranged on a grooved rod. These
rings are typically constructed of stainless steel and have a diameter of 15
mm, an interior diameter of 22 mm, an outside diameter of 22 mm, and a
thickness of 0.8 mm.
3. 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 the receiver from the top.
4. 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 the 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.
Meta Filters are also known as edge filters.
5. Working..
Filters are placed in a vessel
Slurry is pumped under pressure or occasionally by applying reduced pressure
to the outlet side
Slurry passes through the channels formed on the edges between the rings
The clear liquid rises up and collected from the outlet into receiver
For separation of fine particles, a bed of suitable materials such as kieselguhr
is first built up.
The pack of rings serves essentially as a base on which the true filter medium
is supported.
6. Advantages....
Can be used under high pressures, without any danger of bursting the filter
medium.
Running cost is 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 an extremely versatile filter because fine as well as large both types 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.
7. Disadvantages & Uses
It is not a continuous process.
It is used where the proportion of solid in the liquid to be filtered is about 5%
or less.
Uses:
Meta Filters are usually used for-
Clarification of syrups.
Filtration of injection solutions.
Clarification of insulin liquors.
Filtration of viscous liquids can be achieved by applying pressure.
8. Cartridge filter
A cartridge filter is a piece of tubular filtration equipment that can be used
across various industries for an array of filtration requirements. A cartridge is
encased within a housing or a casing and used to remove unwanted particles,
pollutants, and chemicals from liquids.
9. Principle..
The principle behind this filter is that water is pushed through a thin porous
membrane in which pre-filter and membrane filter are combined into a single
unit. As a result, the particles are retained on the surface.
10. Construction...
It consists of a cylindrical configuration having disposable filter media which
are made of plastic or metal. The filter consists of cartridges one of which
acts as a prefilter while another one acts as an actual filter for filtration. The
cartridges are enclosed in the holder. There is also provision for slurry inlet
and filtrate outlet. At the bottom, discharge cake is collected which is
removed from the bottom.
11. Working & Uses
The slurry is pumped into the cartridge holder through the inlet. It passes
through a cartridge filter. The filtration occurs due to the mechanism of
straining. The particles get attached to the surface while the clear liquid
passes to the center. The filtrate moves up and collected through the outlet.
Uses
It is used for the preparation of sterile solutions such as preparation used for
parenteral and ophthalmic. The cartridge filter is also used in the water
treatment plant.
12. Advantages & Disadvantages
This is suitable for sterile operations
Less chance of contamination Ease in disassembling.
Ease in disassembling.
Filter media can be reused.
Cartridges with self-cleaning devices are advantageous.
Cartridges are not brittle when they are dry.
They are used in line with continuous filtration which reduces the handling of
solutions.
Disadvantage:
The cost of disposable elements neutralizes the labor-saving cost.
