Housing and Code
SS304 or SS316L housings designed to ASME VIII Div. 1, for 10 barg and 120 °C as standard, and pressure tested before dispatch. Higher ratings are designed to order.
Bag and cartridge filters
LEAKPROOF Polishing Filter
A polishing filter takes the last fine particles out of a liquid that is already almost clean: oil after the leaf filter, a finished product before storage or loading, or process water before it is used again. LEAKPROOF polishing filters hold one or more filter bags, or a set of cartridges, in a stainless steel housing whose cover and basket seal on O-rings in precision-machined grooves, so that nothing can flow around the filter. Peltech builds them in Malaysia as single-bag, multi-bag, duplex and cartridge filters for edible oil refineries, oleochemical and chemical plants and water systems, and supplies the bags, cartridges, baskets and seals for them.
1 to 12 bagssingle, multi-bag and duplex housings
1 to 50 µmfilter bags and cartridges
10 barg · 120 °Cstandard design pressure and temperature
SS304 or SS316Lpolished inside, sand-blasted or polished outside
Inside the filter
What Is Inside a LEAKPROOF Bag Filter
Loading the 3D model…
1
Swing-Bolt Cover
A dished cover held by hinged eye bolts. Loosen the eye nuts and swing the bolts out: on multi-bag housings the lifting screw raises the cover and the davit arm swings it aside; on single-bag housings it lifts off by its handle.
2
Inlet Nozzle
A flanged side inlet that brings the liquid into the top of the housing, above the mouths of the bags.
3
O-Ring Seals
The cover and every basket seal on an O-ring in a machined groove, so no liquid can pass around the bags. Viton as standard, Buna or silicone on request; two spare O-rings come with every cover and basket.
4
Support Basket
A perforated stainless steel basket for each bag, with a replaceable mesh lining, hangs in the basket plate and carries the bag against the pressure of the flow.
5
Filter Bag
Felt or mesh bags rated from 1 to 50 µm: size 2 in multi-bag housings, size 1 or 2 in single-bag ones. Each ring collar sits in the top of its basket.
6
Housing Body
SS304 or SS316L shell, designed to ASME VIII Div. 1, polished inside so that it stays clean and drains fully.
7
Outlet Nozzle
The filtered liquid from all the bags collects in the bottom of the housing and leaves through a flanged outlet.
8
Vent
Half-inch ports on top of the cover let the air out when the housing fills; they also take a pressure gauge.
9
Drain
A half-inch port at the bottom empties the housing before the cover is opened.
10
Support Legs
Legs with base plates for bolting down. Single-bag housings have legs with an adjustable height, so the nozzles line up with the pipework.
How it works
Six Steps from Inlet to Bag Change
A bag filter works on a simple principle: the liquid flows into the bag and out through its wall, from the inside out. Particles larger than the rating of the bag stay inside it, so all the dirt leaves with the bag at the next change and none of it falls back into the clean side. A polishing filter is not meant to remove a large amount of solids: it catches the little that is left, and anything an upstream filter lets through. The diagram and the six steps below follow the liquid through a duplex bag filter.
Step 1 of 6: Into the BagThe liquid enters the housing above the bag and flows into its open mouth.
Liquid to be polishedFiltered liquidSolids held in the bagAir
1
Into the Bag
The liquid enters the housing above the bag and flows into its open mouth.
2
Out Through the Wall
It passes through the bag from the inside out, then through the perforated basket, and leaves at the outlet below.
3
Solids Stay Inside
Particles larger than the rating of the bag are held inside it, where they stay until the bag is changed.
4
Watch the Pressure Gauges
As the bag fills, the difference between the inlet and outlet pressure rises: the gauges show when the bag is due for a change.
5
Switch to the Standby Side
On a duplex filter the changeover valves send the flow to the clean housing, and the line keeps running.
6
Change the Bag
The used side is drained and vented, the cover opened and the bag lifted out with its dirt; a new bag goes in and the side waits on standby.
Bags or cartridges. Bags hold more dirt and are changed in a minute. Pleated or wound cartridges give a finer, more even polish and much more filter area in one housing, and flow from the outside in. Many plants put a bag filter first and a cartridge filter last.
Why the seal matters. A filter is only as good as its seal: if the bag collar or the cover does not seat, liquid flows around the bag and even the finest bag gives no protection. That is why the cover and the basket of a LEAKPROOF housing seal on O-rings in machined grooves.
Design and construction
Built in Malaysia for Refinery Service
Leakproof Seals
Cover and basket each seal on an O-ring in a precision-machined groove: Viton as standard, Buna or silicone to suit the liquid. Every housing comes with two spare O-rings for the cover and for each basket.
Quick-Release Cover
Hinged eye bolts with eye nuts hold the cover: loosen, swing out and lift. Large multi-bag and cartridge housings carry the cover on a davit arm, so one person can open them.
Smooth Inflow and Outflow
The side inlet feeds the liquid into the top of the bag without stirring up what it has caught, and the outlet at the bottom lets the housing drain fully.
Baskets and Bags
Perforated stainless steel baskets with a replaceable mesh lining, for standard size 1 (7 x 16 in) and size 2 (7 x 31 in) bags in felt or mesh, from 1 to 50 µm.
Connections
Flanged inlet and outlet, ANSI 150 lb as standard, or screwed ends on small housings; from 2 inches on single-bag filters to 5 and 6 inches on large multi-bag housings.
Finish
Polished inside, so that the housing stays clean and is easy to wipe out at a bag change; sand-blasted or mirror-polished outside.
Heating Jacket
Single-bag, multi-bag and cartridge housings can have a heating jacket, for oils and fats that must stay liquid while they are filtered.
Adjustable Legs
Three legs with an adjustable height on single-bag housings, so the nozzles line up with the pipework on site; multi-bag housings stand on fixed legs.
Applications
What Polishing Filters Are Used For
A polishing filter is the last filter before a product is stored, packed or used: it takes out fine traces and catches anything an upstream filter lets through. Plants choose a bag or cartridge filter when the liquid is already nearly clean, and they want a change in minutes, with no cake to handle. These are the usual duties.
Safety Filter After the Leaf Filter
Edible oil refineries
Bleached oil leaves the pressure leaf filter almost clean. A bag filter behind it catches any bleaching earth that gets past a torn leaf or a cracked cake, before the oil reaches the deodoriser.
Final Polish of Refined Oil
RBD oil, olein and stearin
After deodorising and cooling, a bag or cartridge filter gives the oil its final clarity before storage, packing or loading.
Tank and Tanker Loading
Storage and dispatch
A check filter on the loading line keeps scale and debris out of the tanker, the ISO tank or the drum.
Oleochemicals
Fatty acids, methyl esters, fatty alcohols
Polishing of finished products, and safety filtration after hydrogenation, where a bag filter catches catalyst fines that pass the main filter.
Glycerine
Glycerine water and refined glycerine
Bag and cartridge filters on crude and treated glycerine water and on refined glycerine.
Chemicals and Solvents
Process liquids and products
Polishing of products and solvents, and protection of pumps, nozzles and meters from fine particles.
Cooling and Process Water
Cooling towers and chilled water
Bag filters on cooling-tower, chilled-water and process-water circuits keep fine dirt out of heat exchangers and spray nozzles.
Food Liquids
Syrups and edible liquids
Polished stainless steel housings with food-grade seals for syrups, edible liquids and process water.
Other Duties
Ask us with a sample
Tell us the liquid, its temperature, the flow and the rating you need, and we will suggest bags or cartridges and the housing to hold them.
Where It Sits in an Edible Oil Refinery
Bleacher
oil mixed with bleaching earth
Pressure leaf filter
takes out the earth as a cake
Polishing filter
safety filter: catches any earth that gets through
Deodoriser
steam strips taste, smell and free fatty acids
Polishing filter
final polish of the cooled oil
Storage and loading
clear, bright oil to the tanks
The first polishing filter protects the deodoriser if the leaf filter lets earth through; the second gives the finished oil its final clarity. Fractionated olein and stearin and oleochemical products are polished the same way.
When a Polishing Filter Is the Right Choice
- The liquid is already nearly clean and needs a final polish, or a safety filter behind another filter.
- A steady flow with a low, even load of fine solids.
- Quick changes by one person: the dirt leaves inside the bag, with no cake to discharge and no housing to clean.
- A defined rating, from 1 to 50 µm, chosen for the quality the next step or the customer asks for.
- Lines that cannot stop: a duplex filter changes over to its standby side while the line keeps running.
When Another Filter Is Better
- A large load of solids, or solids that must come out as a dry cake: a pressure leaf filter.
- Coarse debris that only has to be kept out of a pump: a basket or Y strainer.
- Liquids too hot for the bag media, or a filter that must be cleaned and used again: stainless steel pleated or sintered mesh cartridges.
For a high load of solids see the LEAKPROOF pressure leaf filter; for coarse debris, the basket strainer or the duplex basket strainer; for hot or reusable duties, stainless steel pleated cartridges.
LEAKPROOF polishing filters work in edible oil refineries and oleochemical plants in Malaysia, Singapore and Indonesia, on glycerine and methyl ester lines, at tank loading points and on cooling and chilled water circuits, many of them as duplex pairs on lines that run around the clock.
Models and specifications
Single-Bag, Multi-Bag and Cartridge Filters
Three types cover most duties. Every one can be built as a duplex pair: two housings of the same model on common inlet and outlet manifolds, with changeover valves, so the line keeps running while one side has its bag or cartridges changed. The flows below are a guide for palm oil; we size each filter for your liquid, its temperature and the rating you need.
Single-Bag Filters, LPDG
One size 1 or size 2 bag, for flows up to about 16 m³/h of palm oil.
Multi-Bag Filters, LPD2-S
Two to twelve size 2 bags under one cover, for flows up to about 190 m³/h.
Cartridge Filters, LPYF
Six to seventy-two 40-inch cartridges held down by springs on a tube sheet.
Single-Bag and Multi-Bag Filters
| Model | Bags | Diameter (mm) | Height (mm) | Inlet / outlet | Flow, palm oil (m³/h) | Volume (L) |
|---|---|---|---|---|---|---|
| LPDG1 | 1 x size 1 | 219 | 820 | 2 in | 8 | 15 |
| LPDG2 | 1 x size 2 | 219 | 1340 | 2 in | 16 | 32 |
| LPD2-S2 | 2 x size 2 | 408 | 1950 | 3 in | 32 | 130 |
| LPD2-S3 | 3 x size 2 | 458 | 1800 | 4 in | 48 | 175 |
| LPD2-S4 | 4 x size 2 | 508 | 2000 | 4 in | 64 | 215 |
| LPD2-S8 | 8 x size 2 | 710 | 2280 | 5 in | 128 | 460 |
Size 1 bags are 7 x 16 inches, size 2 bags 7 x 31 inches. Larger multi-bag housings with 6, 10 and 12 bags (660 and 900 mm diameter, up to about 190 m³/h of palm oil) are built to order.
Cartridge Filters
| Model | Cartridges (40 in) | Inlet / outlet | Flow, palm oil (m³/h) |
|---|---|---|---|
| LPYF0640 | 6 | 2 in | 6 |
| LPYF0740 | 7 | 2 in | 7 |
| LPYF1040 | 10 | 2 or 3 in | 10 |
| LPYF1240 | 12 | 2 or 3 in | 12 |
| LPYF1440 | 14 | 2 or 3 in | 14 |
| LPYF2040 | 20 | 4 or 5 in | 20 |
| LPYF3640 | 36 | 4 or 5 in | 36 |
| LPYF4040 | 40 | 4 or 5 in | 40 |
| LPYF6040 | 60 | 4 or 5 in | 60 |
| LPYF7240 | 72 | 5 in | 72 |
Standard Specification
| Material | SS304 or SS316L |
| Design code | ASME VIII Div. 1 |
| Design pressure and temperature | 10 barg, 120 °C (higher on request) |
| Finish | Polished inside; sand-blasted or mirror-polished outside |
| Seals | Viton, Buna or silicone O-rings |
| Filter rating | Bags and cartridges from 1 to 50 µm |
| Connections | Flanged (ANSI 150 lb) or screwed, 2 to 6 in |
| Options | Heating jacket, duplex manifolds with changeover valves, davit arm, pressure gauges |
Dimensions are for the standard housings; the general arrangement drawing sent with each quotation gives the exact heights, nozzle positions and weights.
Parts and spares
Bags, Cartridges and Spares from Malaysia
Bags, cartridges and seals are what a polishing filter uses up. We keep the standard sizes in stock and make baskets and other parts for our housings in our own works.
Filter Bags
Size 1 and size 2 bags in felt or mesh, from 1 to 50 µm, with a stainless or steel ring; packed in tens.
Support Baskets
Perforated stainless baskets with replaceable mesh lining, for size 1 and size 2 bags.
Pleated Cartridges
A large filter area in a small cartridge, for a fine and even polish.
String-Wound Cartridges
Depth cartridges wound on a stainless core, here seated in an open housing.
Stainless Steel Cartridges
Perforated tube and wire mesh: cleanable cartridges for hot liquids, made to fit your housing.
O-Rings
Cover and basket O-rings in Viton, Buna or silicone, for our housings and for other makes.
Spring Hold-Downs
Springs that keep each cartridge pressed onto its seat, so nothing bypasses.
Eye Bolts and Handles
Swing bolts, eye nuts and cover handles for LEAKPROOF housings.
LEAKPROOF pressure leaf filterThe main filter in front of the polishing filter in edible oil refineries: it takes out the bleaching earth as a dry cake.Pressure leaf filter pageStainless steel pleated cartridgesCleanable pleated and sintered mesh cartridges for hot liquids and for duties where disposable cartridges are not wanted.Pleated filter page
FAQ
Frequently Asked Questions
What is a polishing filter used for?
For taking the last fine particles out of a liquid that is already almost clean, and for catching anything an upstream filter lets through. In edible oil refineries it sits after the pressure leaf filter as a safety filter and before storage as the final polish; oleochemical, glycerine, chemical and water plants use it the same way.
Bag filter or cartridge filter: which do I need?
Bags hold more dirt and are changed in a minute, so they suit safety duties and liquids with a little more solids. Pleated or wound cartridges give a finer, more even polish and more filter area in one housing. Many plants put a bag filter first and a cartridge filter last. Tell us the duty and we will recommend one or both.
How do I choose the micron rating?
By the quality the next step or your customer needs, not by the finest bag available: a finer rating than needed only makes the bags fill sooner. Ratings are nominal unless stated otherwise, so for a strict specification ask us for test data on the bag or cartridge.
When should the bag be changed?
When the pressure difference between the inlet and the outlet reaches the change-out value for your bag and duty, read on the gauges. If the difference drops suddenly during a run, stop and check: a torn bag or a seal that is not seated lets liquid through unfiltered.
What is a duplex polishing filter?
Two housings on common inlet and outlet manifolds with changeover valves. One side filters while the other stands by with a clean bag; when the bag is due, the valves switch the flow to the standby side, and the used side is drained and opened without stopping the line.
What makes a LEAKPROOF housing leakproof?
The cover and the basket each seal on an O-ring in a precision-machined groove, so no liquid can pass around the bag, and the housing itself is designed to ASME VIII Div. 1 and pressure tested. Check the O-rings at every bag change; every housing comes with spares.
Can the filter take hot oil?
Yes. The standard housing is designed for 120 °C, a heating jacket keeps fats liquid, and higher ratings are built to order. Choose the bag or cartridge media for the temperature too; for hot duties stainless steel mesh cartridges are the safe choice.
Do you supply bags and cartridges for other makes of housing?
Yes. Size 1 and size 2 bags and 40-inch cartridges fit most housings. Send the size, the rating, the liquid and the type of ring or end cap, and we will quote bags, cartridges, baskets or O-rings.
Need a Quote or a Sizing Check?
Send us your duty, a drawing or a photo of your existing unit. A Peltech engineer will reply with options and a quotation.