P rogram CHEMICAL ENGINEERING STUDY
FACULTY OF TECHNOLOGY INDUSTRY
U niversitas P Developing N national ProgrammeVeteran East Java
Praise to Allah SWT to convey the author. Because the blessings and gifts Rakhmad I can
finish paper CHEMICAL ENGINEERING OPERATIONS on Filtration these authors have
been able to finish on time.
Papers CHEMICAL ENGINEERING OPERATIONS onFiltration is the author created
as one of the prerequisites in the following subjects are taken care of by the mother Ir. Dyah
Holy P, MT as well as to meet the assessment criteria for each student studying in Chemical
Engineering courses UPN Veteran East Java .
This paper would not be possible without the help of all parties. Therefore in this
opportunity, do not forget to say thanks author profusely to the mother Ir. Dyah Holy P, MT as
a lecturer inChemical Engineering Operations that have a lot of give guidance, direction, and
motivation to the author to be able to understand and correctly understand what is contained in
the subject of Operations of Chemical Engineering .
As a final word, the authors also express gratitude to writer friends, the writer can not mention one by one, over the attention
and assistance in exchanging ideas about the content of the material in the paper the author made CHEMICAL ENGINEERING
Back we thank mother Ir. Lulu Edahwati, MT s elaku lecturer Operations of Chemical
Engineering who have taken the time to read the papers of the author. Thus papers
on filtration as one part rather than the material in the course of Chemical Engineering
Operations writer who can describe in this paper. If there are less or more shall we apologize
Filtration is the cleaning particles of a dense fluid by passing the filtration medium, or
septum, upon which solids will precipitate out. Range filtration in industries ranging from simple
screening to complex separation. Filtered fluid can be a liquid or gas; flow that passes from the
filter may be liquids , solids, or both. One time it padatnyalah waste must be separated from the
liquid waste prior to disposal. In the industry, the solids content of the feed has a range of just a
trace to a large percentage. Often bait modified through some initial processing to increase the
rate of filtration, eg by heating,crystallization , or install additional equipment on filters such as
cellulose or diatomaceous earth. Because of the variety of material that must be filtered and a
variety of different process conditions, many types of filters have been developed, some types
will be described below.
Fluid flows through the filter media due to the pressure difference through the media. Filters can
The pressure in the upper atmosphere at the top of the filter media.
The operating pressure at the top of the filter media.
Vacuum at the bottom.
Above atmospheric pressure can be carried out by the force of gravity on the liquid in a
column, using a pump or blower, or bycentrifugal force . Centrifugal filter discussed in the next
section in this chapter. In a gravity filter media filter can be no better than a sieve (screen) with
rough or coarse particles such as sand bed.Restricted gravity filters in the industry for a fluid
flow of coarse crystalline, water purification drinking, and wastewater treatment.
Most filters are industrial filter press, vacuum filter, or a centrifugal separator. These filters
operate continuously or discontinuous, depending on whether the discharge of solids filtered
steady (steady) or intermittently. Most of the operating cycle of the filter discontinuous, fluid
flow through the equipment continuously, but must be stopped periodically to remove solids
accumulated. In the continuous filter effluent suspended solids or fluids not during equipment
Filters are divided into three main groups , namely filter cake (cake), filter purification
(clarifying), and a cross-flow filter (crossflow). Filter cake solids separated by a relatively large
amount as a crystal or mud cake, as seen in Fig. 30.4.a. Often the filter is equipped with
equipment to clean up the cake and to clean up the liquid from the solids prior to
discharge. Purification filter cleaning small amounts of solids from a gas or liquid splashes clear
beverages such. Solid particles trapped in the filter medium (Gb. 30.4.b) or on the outer
surface. Different purification filter with regular filter, which has a filter medium pore diameter
larger than the particles to be removed. In the cross-flow filter, the feed suspension flows with
particular pressure on the filter medium (Gb. 30.4.c). A thin layer of solids can be formed on the
surface of the medium, but the high velocity fluid prevents the formation of layers. Membrane
filter medium is ceramics, metal, or polymer with pores small enough to hold most of the
suspended particles. Most of the fluid flows through the medium of the clear filtrate, leaving
pekatnya suspension. Further discussion, an ultra filter, cross flow unit contains a membrane
with very small pores, is used to separate and concentrate the particles ofcolloidal and large
Retrieved from " http://id.wikipedia.org/w/index.php?title=Filtrasi&oldid=6196643 "
Fa k tor - fa k tor affecting Filtration
1. discharge filtration (where discharge is too large will cause the failure of the filters efficiently.)
2. concentration (concentration was used effects the efficiency of filtration. extremely high
concentration of water will cause clogging of the pores of the media ata hole will be clogging)
3. Temperature (a change in temperature of the water to be in filtration, will cause the density,
viscosity will change. Additionally it also will memepengaruhi affinity dianatara fine particles,
so terjaid difference in the size of the particles to be filtered.
4. Depths of media, sizes and materials (media selection and size is an important decision in
planning the building filters. thickness of thin media will determine the length of the drainage
and filter power. too thick media filter usually has a very high power, but it takes a long drainage
5. High water levels on the media and the pressure loss (state water level above the media affect
the magnitude of the discharge or the rate of filtration media. Availability of water level is high
enough above the media will improve the tap water to get into the pores. With high pore face
will meningkatnkan filtration rate).
For all the filtration process, the feed flow due to a pressure differential thrust force, for
example, due to gravity or power swivel.In general, the filtration is performed when the amount
of solids in suspension is relatively smaller than the melting substances.According to the
working principle of filtration can be divided into several ways, namely:
a. Pressure Filtration
Filtration is done by using pressure.
b. Gravity Filtration
Filtration of fluid flow due to gravity.
c. Vacuum Filtration
Filtration with liquid flowing because the principle of vacuum
Filtration by gravity is the oldest way to purify a suspension. The image below has been widely
used as purification through sandfilter.
Figure 3. Filtering by gravity
Flate AND FRAME FILTER
This tool will work based on the driving force , ie the difference, press. This tool is equipped
with so-called filter cloth filter cloth , which is located on each side of platenya. Plate and frame
filters are used to separate solids liquids with porous media that continue to hold the liquid and
the solid. In general filtration, performed when the amount of solids in the suspension is
relatively small compared to the melting of the substance.
1. Open Delivery Filter press
Channels for slurry and wash (wash) through the inlet and each platefor the liquid channel.
2. Closed Delivery Filter Press
Having multiple channels slurry and wash water . Feed slurryentering through the inlet
port. filter cloth located on each side of the frame . Pressure is applied to the slurry to pass
through the filter clothto be able to enter into the plate and frame filter then exit through the
hole plate as filtrate. Solids will accumulate or be left behind and stick to the cloth . After some
time, the space between the plates will accumulate by the slurry and gradually feed will stop
flowing. If this is the case then the cloth should be washed. Washing is done by channeling water
into the plate and out through the frame . This is the kindness of the filtration process ( Closed
delivery ) .Berdasarkan kompresibilitasnya cake ( slurry which is attached to the cloth) is divided
into two, namely:
1. compressible cake
Cake will undergo structural changes when subjected to pressure so that the empty space in
the cake gets smaller as a result the process of retaining the greater and the more difficult the
process of filtration.
2. I ncompressible cake
Cake is not changed if a change in pressure. In fact this group is almost non-existent. But then
the pressure used small cake can be considered incompressible cake . For the filtration process
generally occurs at a constant pressure difference. If the primary filter mediumhas been
coated cake and the filtrate was saturated, the pressure will increase to the maximum. The
optimum time required to perform one-time siklus.Waktu optimum filtration is the filtration time
it takes for the amount of volume of filtrate per unit maximum time, in the so-called filtration
cycle time is the total time required to perform the filtration process, which is:
ts tf tw tp
ts = cycle time
filtration time tf = true
tw = leaching time
tp = time apart pairs
Laundering / Washing
Optimization of the amount of wash water used in the slurry is added dyes which have the
property not permanently bind / strongly with solids, so easily washed away by water
washing. Dye concentration in the wash water out of the filter is analyzed to determine how far
washing operations performed. Washing was stopped if the color levels in the wash water has
begun to constant. The amount of washing water is recorded as the optimum volume.
ROTARY DISK FILTER Vacuum
Rotary disk vacuum filters used in the operation of large scale continuous process. Media filters
can be either fabric ( cloth ), paper, media and other shaft. Cooptation filter media is based on the
ability to separate solids, have the power, inert to chemicals and also in terms of its economy.
The working principle
Slurry to be filtered occupy a place (basin). Leaf dipped into the slurry and collecting cake at his
premukaan leaf (not filtrate). Filtrate exit through the main exit channel. Cak e brought up to the
top.Several other types:
1 Horizontal rotary vacuum filters
2 Horizontal leaf filters
3. Vertical leaf filter
(Practicum Module CHEMICAL ENGINEERING LABORATORY OPERATIONS OF
CHEMICAL ENGINEERING DEPARTMENT UNIVERSITY SULTAN ageng Tirtayasa
CILEGON - BANTEN 2008)
The main thing is the filtration of fluid flow through porous media.Filtration can occur due to
thrust, for example; gravity, pressure and centrifugal force. In some processes assist beam porous
filter media (cake) to hold the solid particles in suspension, forming consecutive layers on the
beam as the beam passed through the filtrate and the media.
Filtration is usually done on a laboratory scale to pilot plant slaka / industry either
by batch or continuous.
a) Filtration Laboratory Scale.
Filtration is used to separate a heterogeneous mixture of solids that do not dissolve in the
liquid. Filtration using a glass funnel and filter paper and the filter is called the filtrate.
Figure 1 Filtration laboratory scale
b) Filtration Industrial Scale
Before the filtration equipment used should be examined first in order not to avoid things that are
not desirable at the time of operation, for example, filter does not function at its optimum. Fluid
flows through the filter media because of the pressure difference through the media. filter is done
in order to operate on:
1) above atmospheric pressure at the top of the filter media
2) The operating pressure at the top of the filter media
3) And the vacuum at the bottom
Above atmospheric pressure can be done by the gravitational force on the liquid in a column,
using a pump or blower, or by centrifugal force. In a gravity filter filter media bias so no better
than a sieve (screen ) using a coarse or coarse particles such as sand.
Restricted gravity filters in the industry for a fluid flow of coarse crystals, drinking water
purification, and wastewater treatment. Most filters are industrial filter press, vacuum filter, or a
centrifugal separator. These filters operate continuously or discontinuous, depending on whether
the discharge of solids filtered continuously (steady ) or only partially. Most of the operating
cycle of the filter discontinuous, fluid flow through the equipment continuously, but must be
stopped periodically to remove solids that accumulate. In the continuous filter effluent suspended
solids or fluids not during equipment operation.
2 Classification of filtering
In some filtration, solids-strain formed a good filter medium. Based on the flow driving force,
filtering can be classified as follows:
1 Filters gravity (gravity filters)
is the gravity drainage system from the source to the reservoirby way of utilizing the
gravitational potential energy of water held due to differences in altitude location with
the location of the source reservoir
2 Filter pressure (Pressure filters)
A pressing machine bersaringan contains a set of plates that are designed to provide a series of
space or compartment in which solids are collected. The plates are covered filter medium such as
canvas.Mud can reach each compartment with a certain pressure; fluid through the canvas and
out to the drain pipe, leaving behind a wet cake solids.
3 Filters Vacuum (Vacuum filters)
4.Penyaring centrifugal (Centrifugal filters)
Form a porous cake solids can be separated from the liquid by filtration spin. Feed inserted into a
rotating basket that has a slotted or perforated walls that disampuli a filter medium such as
canvas or metal fabric. The pressure resulting from the centrifugal force forces the liquid through
the filter medium, leaving the solids. If the incoming feed baskets suspended solids cake and
played for a short time, most of the liquid residue in the cake so that the solid particles flow drier
than the same thing for bersaringan pressing machine (filter press) or filter vacuum (vacuum
filters). When the material to be filtered sequentially dried with a heater, the use of these filters
can be considered as an economical step.
Based operations are divided into:
1 batch mode (gradual)
2 Ways continuously (continuous)
Types of filters:
1) Filter sand (sand filter):
2) filter press (filter press):
a.Pelat hollow (recessed plate)
b.Pelat and frame (plate and frame)
3) Filters - leaves (leaf)
Filters Moore is an indigenous leaf filter. Set of filter leaves dipped in a slurry tank, filter leaf
vacuum associated with the production system.
Rectangular filter, placed in a horizontal cylindrical vessel. This filter leaves dikeluar set to enter
the vessel with the help of rails and wheels.
This filter and the same great circle. Filtering is done in a pressure vessel.
This filter is placed in the vertical and horizontal tank.
4) Filter tube (tubular / candle filter)
5) Filter - drum
a. Oliver (Rotary drum)
b. Topfeed (Dorco)
6) Filter Belt landscape (horizontal belt filters)
filter serves to hold and support the solid particles. Good filter condition:
- Mechanically strong
- Corrosion resistant (to the fluid handled)
- Provide little resistance to the flow (large porosity)
The kinds of filters include:
a. Filter Gravity (Gravity Filter)
It is the oldest type and simple.
This filter is composed of tanks bottom with holes and filled with porous sands where laminar
These filters are used to process large quantities of fluid and contains few solids. For example:
the purification of water.
The tank is usually made of wood, brick or metal but for water treatment commonly used
concrete. The bottom of the hollow channel leading to the filtrate, the channel was equipped
with a door or a tap to allow backwashing of the sand base to remove accumulated solids. The
bottom of the hollow enclosed by rocks or gravel as high as 1 ft or more to hold the
sand. Sand is commonly used in water treatment as a filter media is quartz sand in a uniform
shape. Crushed coke typically used to filter the sulfuric acid. Limestone is commonly used for
cleaning both the organic liquid filtration and adsorption.
It should be considered in the gravity filter, coarse chunks (stone or gravel) placed the top of the
porous block (cake) to hold little material available on it (sand, etc.). The material must be
placed with a different size to form layers that can be mixed and size for each material should be
equal to the pores and provide maximum capability.
b. Filter Plates and Frames
Pressure filters are usually composed of plates and frames. In this filter plates and frames
arranged alternately with filter cloth with the opposite direction on each plate. Installation is
carried out simultaneously as a unified force mechanic (by screw / hydraulic).
There are several types of compressed using plate and frame. The simplest have one single
channel to recognize the suspension in washing and a single opening on each plate to
mangalirkan fluid (open on delivery). The other type has a separate channel to distinguish the
suspension and washing water, but there is also a separate channel for separating the suspension
and washing water (closed on delivery). These channels are usually found in a corner or in the
middle or right in the middle.
Feed suspension makes malalui channel formed by the holes on the top right corner between the
plate and the frame. From this channel, the suspension went into the frame toward the space
between the plates. Pressure on the suspension fed to the process of suppression to produce
filtrate. The filtrate into the spaces between the fabric and plates through the fabric of both sides
of the plate to the outcomes of the valve or to the second channel formed by the holes in the
other corner of the plate and frame with output supported by the plates not by frame. Both output
through the channel or through the tap or valve and perforated plate or made with the filtrate,
entering through the output side of the plate.
Solids in suspension accumulate in the fabric on the reverse side of the plates. After some time a
small portion of space between the plates is available for suspension, and the feedback is turned
off. If the cake is washed, washer fluid in it is channeled into the suspension or turning input bi
mix suspension, entering into approximately cake from the middle frame, and passing to the
plate on both sides. After the cake is washed, the flow is stopped, the force that holds the plate is
released, plate and frame open at once, and the cake is removed or disposed of in a hole under a
pressure. After disposal is completed, suppressor closed again by providing a mechanical force
for plate and frame lock together, and a new cycle begins filtration.
Washing can be removed separately from the filtrate by providing a second output taps and down
through a separate channel at the other corner of the plate.
Simple washing is when laundering flows through the cake in the same way as the filtrate. The
expression "trhough washing" or "every other pelate washing" requires the use of two different
types of plates.Plates were not washing (one button) and plate washing (three buttons) contained
in the suppressor between the frame (two buttons).Feed enters the frame as before. Wash each
plate and passes into the two cake on the frame on both sides of the plate, leaving the tap on the
plate instead of dessert (one button). This method requires a closed valve on the plates (three
button) input into the washer.
Semuam plate type can be designed to operate on a closed delivery by providing a third channel
formed by a hole in the bottom right corner plates and frames. Four channels allow to operate by
using the enclosed shipping with separate outputs for filtrate and washing. Feed the suspension
went into every frame through the top right channel (no opening of this channel to any
plate). The filtrate was left every plate toward the lower left frame channel filled with
cake. Washing in through the left channel up to each plate to the double cake in the frame on the
other side of this plate and exit through the right channel at the lower replacement plate (one
button). During washing the taps on the output and input filtrate leaching closed.
Suppressor plate and frame are very widely used, especially when the cake is very valuable and
very small size. Continuous filter plates and frames replaced suppressant for many large-scale
Picture Filter Plate
c. Batch Leaf Filter
Leaf filter similar to the filter plates and frames, in which the cake is stored on each side
of the leaf and the filtrate flows out through the drainage channels of the filter are rough
on the leaves of the cake, the leaves are immersed into the suspension.
Filter leaf remains (type Sweetland), leaf filter rotates (Vallez type) which is more
uniform cake, Kelly Filters in the open position. Closed and the input filter faucet open
so that the suspension can get into the shell with air vents that were transferred from
the shell to the top of the back. Ventilation can be closed or left open after a full
sleeve. If the faucet is left open, then the faucet will restrict the flow of excess and will
return the excess to the tank bait feeder so as to provide better circulation between the
filter leaves and to keep large particles from settling filtration was continued until the
desired thickness is reached or filtration mean The average fell sharply.
Feed silenced briefly, then open the output channel slurry flow.Low air pressure
supplied to the tank to add the excess solution. The difference in pressure will help keep
the cake in the fight against the filter cloth. Once the filter is empty, the lid can be
cleaned or drained of excess air to dry the cake first.For excess washer fluid drained at
the end of the washing in the same way as the excess slurry and cake fed with air. Lid
is opened and the cake discharged pressurized air.
Example: making of Mg from seawater.
d. Filter Press
A pressing machine bersaringan contains a set of plates that are designed to provide a
series of space or compartment in which solids are collected. The plates are covered
filter medium such as canvas. Mud can reach each compartment with a certain
pressure: fluid through the canvas and out to the drain pipe, leaving the solids
behind. Plate of a pressing machine can bersaringan rectangular or circular, vertical or
horizontal.Most of the solids compartment formed by the mold plate made
polipropelina. In another design, the kompertemen formed in the mold plate frames
(plate-and-frame press), in which there is a rectangular plate which on one hand can be
changed.Operation is as follows:
1. Plate and frame mounted in a vertical position in a rack metal, with fabric covering the
surface of each plate, and pressed hard along with rotate the hydraulic couplers.
2. Sludge enters a final side of the circuit plate and frame.
3. Mud flows along the path at the corner of the circuit.
4. Additional lanes and the sludge drain the main line into each frame.
5. Solids will be deposited on top of the cloth that covered the surface of the plate.
6. Fluid penetrates the fabric, down the lane on the plate surface (corrugation), and out
of the press machine.
7. After stringing press machine, mud pump inserted or pressurized tank at a pressure
of 3 to 10 atm.
Picture Filter Press
Care must be treated as continuous filtration to equipment lifespan becomes longer. Care
measures as follows:
Media filter is cleaned by using diblower air so that the particles that exist in the filter pores
does not stick anymore.
Bag filters for gas cleaning media also cleaned adri solids or particles.
Filter shelled and leaved also cleaned of dust and rust so that the filtration media will work at
Equation (formula) the basic rate of filtration in a batch process.
t = time or duration of filtration (seconds)
V = volume of filtrate m3
Δp = pressure drop, N / m 2
A = area of filter, m2
μ = viscosity, Pa.s or kg / ms
α = barriers cake, m / kg
Rm = the resistance of filter medium against
flow filtration, m-1
Gravity filter merupakan tipe filter yang paling tua dan paling sederhana, contonya adalah penyaring
pasir terdiri dari tangki dengan alas berlubang – lubang, diisi dengan pasir porous yang dilalui fluida dalam
aliran laminar. Dipakai untuk memproses fluida dalam jumlah besar yang mengandung sejumlah kecil padatan
sebagaimana dalam proses penjernihan air
Bahan tangki dari kayu, baja, atau logam lain untuk pengolahan air tangki dibaut dari beton. Saluran –
saluran pada alas yang berlubang – lubang mengalirkan filtrate dari lapisan. Saliran dilengkapi dengan pintu
atau kran untuk pencucian balik lapisan pasir mengusir zat – zat padat terakumulasi dengan cara aliran balik.
Alas yang berlubang – lubang ditutup oleh lapisan setebal 1 ft atau lebih dari crushed rock datau coarse gravel
( kerikil kasar ) untuk menahan pasir diatasnya. Pasir kuartsa dengan ukuran uniform dipakai sebagai filter
medium dalam pengolahan air.
Graded crushed limestone digunakan untuk filter medium bagi alkaline liquor. Lapisan arang ( charcoal
bed ) untuk penjernihan organic liquors yang bekerja sebagai filter dan sekaligus sebagai absorber. Ukuran –
ukuran bahan hendaknya diatur dalam lapisan – lapidan ukuran yang berbeda jangan dicampur. Pasir yang
digunaka hendaknya uniform dalam ukurannya, supaya memberikan porositas atau kecepatan filter
gambar gravity filter
Tekanan pada vakum filter dibuat dengan memakai lapisan pada sisi aliran hilir ( down stream ) untuk
beban yang tinggi. Lapisan filter dapat dipasang pada bejana tertutup dan beroperasi dibawah tekanan. Bag
atau hat terdiri dari kantong – kantong kain anyaman atau flannel dimanapun umpan campuran masuk
dibagian dalam seperti vacuum cleaner. Kapasitas filter ini rendah biasanya digunakan dalalm system batch.
gambar pressure filter
Terdiri dari plat dan frame filter, setelah penyaringan yang cukup lama, hanya sebagian kecil ruanga
antara plate – plate yang tersedia untuk slurry maka umpan ditutup. Jika cake dicuci, fluida pncuci yang jernih
dilewatkan kedalam slurry atau canmpuran inlet atau dibelakang slurry masuk kedalam cake disekitar pusat
frame lewat menuju plate pada sisi – sisinya. Setelah cake dicuci aliran ditutup, gaya tekanan mekanik yang
menjaga plate – plate bersatu dilepas, plate dan frames dibuka, cake dibuang ke dalam parit di bawah filter,
setelah pembongkaran sempurna, press ditutup lagi dan siklus penyaringan baru dimulai.
gambar intermittent filter
Leaf filter serupa dengan plate dan frame filter, yaitu bahwa cake menempel pada kedua sisi dari leaf daun dan
filtrate mengalir keluar dalam saluran yang disediakan saringan drainase kasar pada leaf diantara cake. Leaf
filter pada prinsipnya terdiri dari kawat berat, bentuk segi empat dan sebuah saluran tram buntuk U. Bagian
saringannya ditutup dengan kain saring. Pada penyaringan filtrate jernih melalui filter cake dan filter cloth dan
dikeluarkan melalui saluran berbentuk u yang membawanya ke outlet. Sejumlah leaf ini digabung membentk
filter daun – daun sepenuhnya tercelup dalam slurry umpan pada saat filtrasi dan dalam saluran pencucian
pada saat pencucian. Sehingga seluruh rakitan bias berada dalam suatu shell tertutup, sebagaimana dalam
pressure filter sederhana dapat dicelup tangki terbuka yang berisi slurry. Daun – daun diberi jarak agar cake
terbentuk tanpa terganggu oleh lapisan cake pada daun didekatnya. Untuk pencucian, kelebihan slurry
biasanya dibuang bersama – sama dimasukkan udara tekan.
gambar leaf filter
Continuos Rotary Vacum Filters
Rotary vacuum filter mempunyai bentuk menyerupai drum maka sering pula disebut rotary drum filter, dipakai
dimana dikehendaki operasi continue, terutama untuk operasi – operasi jumlah endapan besar atau operasi
Filter drum dicelupkan kedalam slurry. Pemakaian vakum pada medium filtrasi menyebabkan cake menempel
dipermukaan luar drum. Bagian ini terlihat didalam gambar sebagai cake forming. dDrum dibagi menjadi
beberapa segmen, masing – masing dihubungkan katup putardimana dipakai vakum dan melalui filtrat, air
cucian dan udara diambil. Segmen – segmen ini biasanya mempunyai lebar 1 ft dan panjang selebar drum
Pencucian dari outlet bila kompartemen yang bersangkutan sedang mencuci. Filtrat dari cairan cucian
biasanya ditampung dalam tangki terpisah. Masing – masing dijaga dalam keadaan vakum jika filter
dioperasikan oleh isapan. Zona dewatering menggunakan udara bertekanan. Tekanan balik ini atau tiupan
akan mengendorkan cake dari medium filtrasi. Dan cake diambil menggunakan scraper atau dextor knife.
Continuos rotary filter mempunyai luas permukaan yang besar, pencucian yang lega, ukuran bermacam –
macam. Mulai dari yang kecil sampai yang besar.
Disk Type Filter
Prinsip operasi filter ini sama dengan drum filter tetapi filter area disusun dalam bentuk disk / piringan.
Setiap piringan individual dapat diganti secara bebas. Dan sementara piringan –piringan lain terus beroperasi.
Dengan memisahkan slurry kompartemen untuk sekelompok piringan yang berbeda misalnya dengan
memasangkan plat pemisah dalam tangki slurry, maka dua atau lebih produk dapat difiltrasi secara simultan
dan terpisah pada filter yang sama untuk filtrate yang dicampur. Jika filtrate harus dipisah, maka hanya dua
macam produk yang dapat ditangani sekaligus sebab hanya dua keran yang dipakai.
Internal Rotary Drum Filter
Merupakan filter drum yang berputar, menyaring pada luas perferi sebelah dalam. Karena perjalanan
yang pendek antara cake forming, washing dan zona discharge filter tipe ini tidak memuaskan untuk slurry
yang pennyaringannya lambat tapi filter yang baik untuk slurry yang pengendapannya cepat dan tidak
memerlukan pencucian. Kesulitan untuk mempertahankan slurry semacan ini dalam suspense menyebabkan
filter tipe ini tidak memuaskan untuk penyaringan slurry tipe itu.
gambar internal rotary drum filter
Termasuk dalam internal drum filter permukaan. Filtrasi diisi dalam drum, drum bergerak / berputar oleh rolls
yang berputar. Satu ujung drum terbuka untuk pengambilan cake dan untuk mengamati proses filtrasi. Kran
automatic dipasang pada ujung tertutup dari drum. Slurry diumpamakan langsung kedalam drum dan
membentuk kolam pada alas. Setiap kompartemen melalui bawah slurry akan terbentuk cake. Discharge
terjadi didekat puncak pada sisi turun oleh gaya berat ( gravity ) atau tekanan pendorong jatuh kedalam talang.
Rotary Horizontal Filter
Merupakan vakum filter dengan permukaan filtrasi dengan bidang horizontal yang terbentuk oleh suatu annular
plan. Piringan dibagi kedalam sector – sector yang sama. Masing – masing mempunyai suatu outlet terpisah
ke kran filtrasi yang terletak dipusat dekat lempengan. Perbedaan operasi yang utama dengan operasi rotary
drum lain adalah dalam pengambilan cake.
Cake diambil dengan cara dimiringkan dari sector dan jika perlu memakai sedikit hembusan balik. Filter
horizontal sangat sesuai untuk menangani free filter material terutama bila zat padat mempunyai tendensicepat