Agitated Nutsche Filter consists of a cylindrical shell with a welded
dished end at the top and a flat welded end at the bottom. The vessel is
divided into two compartments by means of a perforated plate, provided with
suitable filter cloth. The base plate is having arrangement of bolting bar
to hold the filter cloth. Suitable support mesh is provided under filter
cloth to facilitate the flow of filtrate. An agitator of unique design and
rigid and in "S" curved provided inside the vessel to perform the
movements of vertical and rotational directions simultaneously, by means of
push buttons switches/PLC. and to take the high torque generated during
solid discharge and re-slurring operation.
Slurry is fed into the top compartment from where filtrate passes into the
lower chamber en route to receiver. Solids are deposited on the filtering
media in the top compartment and take the shape of cake of a uniform
thickness. The agitator pushes the solid content in the slurry upwards by
keeping it under suspension till maximum possible filtrate passes through
the filter bed. It then seals the cracks in the cake, which develops after
most of the filtrate has passed through, by smoothening the top surface of
Agitated Nutsche Filter Dryer also squeezes out some of the moisture in the
cake by slightly pressing the cake uniformly with the help of specially
designed blades. After the separation of solvent/mother liquor and if the
cake requires washing, the entire cake can be re-slurried and agitated, so
that all the particles forming the cake can be exposed to wash liquor and be
thoroughly washed through the specially designed agitator. This improves
quality of the finished products. After washing and removal of wash liquor,
the cake can be discharged through a quick opening side discharge door, by
rotating and lowering agitator in the discharge direction. No manual
handling is required.
OPERATION CYCLE OF ANF :
- CHARGING: Slurry is charged into filter preferably by gravity
flow from Reaction installed above the filter or by slurry pump.
- FILTRATION: While charging the slurry into the filter,
filtrate will start passing through filter cloth by gravity. To enhance
filtration rate and to keep filter media clean from initial
sedimentation, the agitator can be brought down most position and keep
on rotating in forward direction. The cake height can be built up in
- CAKE WASHING: Wash liquids are sprayed into the chamber on
cake through a spray ring. The stirrer blades are lowered to agitate the
slurry to obtain good cake washing. The wash liquid is sprayed
repeatedly though the filter cake by the same driving force as used
during the first stage filtration.
- SMOOTHING AND COMPRESSION: At the closing stage of the
filtration process described above, the stirrer blades are lowered on
the cake surface. The specially designed hydraulic system, takes over to
perform a systematic, efficient and productive smoothing of the cracks
which appear in the cake, leaving behind low residual moisture 10 to 20%
less as compared to other conventional filters. This results in energy
saving in drying process at least by40%.
- FILTER CAKE DRYING: After the final wash, filtration and
compression, the heating medium is fed into the limpet/jacket and the
chamber below filter plate as well as Hollow shaft and Hallow Blade .The
stirrer blades are lowered and the cake mass is agitated during the
drying stage. The vapour can be removed under vacuum applied to the
filter. Drying can be enhanced by purging a hot gas through cake.
- PRODUCT DISCHARGE: The stirrer blades are rotated and lowered
to cut away the upper surface off the filter cake. As the blades descend
into the cake mass, the discharge value is opened and a controlled
discharge of the cake is achieved.
Multipurpose Design :
Filter Base :
- Unique filter plate design allows interchangeability of filter media
without changing the base.
- Flexibility for multiple products and campaigns in the same
Main Vessel :
- Bayonet type design available as an alternative to C clamp design.
Side Discharge Valve :
- Designed and manufactured according to ASME Sec. VIII Div. I.
Side Discharge Port :
- Hydraulically operated valve with metal to elastomer sealing allows
for a pressure tight shut-off after each product discharge.
- Fully automated, sealing surfaces do not require cleaning after each
- Specially designed metal to metal sealing is available as an option
with selflocking arrangement to prevent loss of batch in case of
Control Panel and Automation :
- For contained discharge of the product a side discharge port can be
provided which can be integrated with an isolator.
Hydraulic power pack with electrically operated flame proof solenoid
valves. Local control panel with electrical and hydraulic safety features.
STUFFING BOX :
Stuffing boxes accomplish sealing by the radial expansion of a soft,
deformable material such as layer-wound rubber, plastic, fiber, or a
combination of these. Stuffing boxes are lower in initial cost than
mechanical seals but are significantly higher in maintenance expenses.
Mechanical Seal :
Mechanical seals are designed to prevent leakage between a rotating shaft
and its housing under conditions of extreme pressure, shaft speed and
temperature. Mechanical seals can be single acting or double acting. Single
(acting) mechanical seals have one sealing gap.
- The equipment is functionally safe and easy to operate.
- No manual handling.
- Through washing of cake.
- Toxic and hazardous material can be processed.
- Product purity maintained
- Blending of product possible before discharging.
- Complete automation.
- Combining filtration, washing, re-slurry and drying in a fully
enclosed automated unit thus reduction of capital and operating costs.
- Large quantities can be processed faster than the conventional
- Heat transfer surface can be provided on the vessel wall by providing
jacket or limpet.