How to choose the right vacuum conveyor filters?
Compare filter types, check specs, or order a replacement part.
This article is a tribute to vacuum conveyor filters! Read more to figure out how they emerged in time following the needs and to learn which parameters affect their function.
We have continuously developed the filter range and our vacuum conveyors based on our users’ needs. I have worked at Piab for 29 years, and I am glad to work for a company that invests heavily in R&D. It is fantastic to see the evolution of our products. They have become easier and easier to set up and operate, as well as smarter. The modular design makes it easy to scale the capacity up and down and to accommodate different material types and changeovers.
The main filters
The filters are the lungs of the vacuum conveyor. They clear out the dust that would otherwise contaminate the manufacturing facility and the lungs of the operators. They also make sure to keep the vacuum pump operational, and they ensure compliance with the rigorous and ever-changing safety regulations and other demands on health and safety within various processes. The position of vacuum conveyor filters varies - from inside the conveyor body to being placed externally in air inlets to ensure compliance with higher demands.
Vacuum conveyors provide a contained alternative to bucket elevators, screw conveyors, or other mechanical solutions to transfer powders and granules. Still, expectations and requirements have changed a lot throughout the past decades. As a response, the mounting of filters became easier, the filtration grade and air permeability increased, and the design became modular. Compared to the one-filter set up in a 1991 Piab vacuum conveyor series, devices today feature 1, 3, or 7 filters, depending on the conveyed volume or the conveyor size.
Also, the introduction of the built-in air shock assembly made the conveyors easier to set up and clean, leading to a longer filter life and higher production capacity due to less need for cleaning filters during production. The vacuum filter shock system today is built into each Piab vacuum conveyor, integrated with the top lid of the conveyor. These devices have a cyclic operation, and the conveyed material is ejected by the end of each period to a receiving vessel or device. When a period is over, the filter gets cleaned by a filter shock. Each filter has its own filter shock for the highest level of efficiency.
Location of internal filters
Filters are used in many different locations in a vacuum conveying system. The main ones can be found in the conveyor body (2), and they ensure the proper basic functioning of the conveyor: when air is added to the conveyed bulk powders, granules, or small parts, the air has to be removed and filtered before it flows out to the surrounding atmosphere. They are cleaned with filter shock (1).
Cleaning with filter shock
The filter shock system consists of one tank per filter that creates the filter shock by the end of each vacuum conveying cycle. During operation, the filter collects dust on its outer side while the vacuum pumps pull the material toward the filter. But during the air shock, the opposite happens: the air is blown from the inside out of the filter in a fierce shock which makes the filter release the material.
Other ways to clean internal filters
Most Piab filters can be cleaned with dry cleaning by repeated filter shocks and also by gently brushing with a non-abrasive brush or camel hair brush to avoid damage to the membrane. Wet cleaning of filters is also possible: the filter can be rinsed using an indirect water spray with a standard low-pressure water hose (maximum 1 bar) while still mounted on the filter support. After cleaning, the filter should be hung to allow drying in an open position. Wet In Place method can also be used on them– some filter types just need more time to dry after they have been cleaned due to a larger filtering surface.
Sizing and maintenance
Modularity for easy maintenance
Piab's standard filters capture particles as small as 0.5µm (since 2000), enabling wider material handling and compliance with stricter regulations.
Key maintenance benefits:
- Modular design for maximum flexibility
- Threaded or press-fit installation — no tools required
- Fast assembly and disassembly
- Spare parts typically ship within 10 days* when not in stock
*Local terms and conditions apply. Consult your nearest Piab representative.
How often should filters be replaced?
Replacement frequency depends on industry, conveyed materials, capacity, and environmental factors.
| Application | Typical replacement |
|---|---|
| Pharmaceutical (frequent cleaning/sterilization) | Every 6 months |
| Ceramics (erosive materials) | Every 6 months — use shorter filters |
| General applications | Yearly (average) |
Tip: Always keep spare filters in stock to avoid downtime.
What to consider when choosing a filter
Particle size
Finer powders require a larger filtering area for maximum conveying ability. Compliance requirements also influence sizing.
Hygroscopic, sticky or bridging materials
Materials with more than 25% fat content or high humidity exposure (e.g. sugar in tropical climates) tend to cake or bridge.
Rule of thumb: if you can form a snowball with the material, it's likely a bridging material. Smaller, smoother filter areas handle these powders best.
Pressure drop
Smaller filter areas can cause pressure drop and reduced conveying ability. This is offset by:
- High air permeability filter materials
- Easy cleaning via air shock pulses
Pipe and system design
Filter choice also depends on:
- Pipe length — longer distances require larger pumps
- Pipe diameter — higher capacity needs wider pipes
- Number of bends in the pipe layout
Second-stage filter units with ULPA filter
When hazardous materials are conveyed, the filters can be completed by second-stage filter units, which work even with extremely small particle sizes from 0.2 µm. Featuring ULPA filters, these second-stage filter units are suitable for particularly fragile products in general. They are placed between the conveyor body and the pump. Second-stage filters are required whenever high-containment requirements (OEB 4 or 5) apply. Read more about OEB solutions here.
Overview of the main filter types at Piab
Sintered, textile, pleated rod, pleated stainless steel, and pleated filters are placed inside the conveyor body. Piab internal filters were designed to ensure maximal security and capacity simultaneously so that you can breathe in calmly at your production line. Compare the main filters with a comparative table below. To get more detailed information on the products, visit the product pages.
Meet the Sintered filter
Sintered filters are Piab’s new standard for secure, hygienic vacuum conveying. Made from a single PFAS‑free polyethylene body with no glued joints, they withstand corrosive materials and cleaning up to 121 °C while delivering a large filtration area in a compact format. The smooth unibody design is easy to clean and reuse, even with sticky powders, and each filter includes an NFC chip that links directly to product and cleaning information for traceable, data‑driven maintenance.
Compare the key characteristics of our main filter types to choose the right option for your vacuum conveyor.
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|---|---|---|---|---|---|---|
| Sintered filter | Textile filter | Pleated rod/antistatic filter | Pleated rod/white filter | Pleated filter stainless steel | Pleated filter fiber/cellulose | |
| Code in configurator | Coming soon | TX1, TX2, TX4, TX6 | PR1, PR2, PR4, PR6 | PR0, PR1, PR2, PR4, PR6 | SS0, SS2, SS4, SS6 | P0, P2, P4, P6 |
| How to select? |
Robust, strong, PFAS‑free unibody filter with twisted compact geometry. Washable and sterilizable, with an integrated NFC chip for easy maintenance and traceability. |
The cost‑effective, flexible solution – the food industry champion. Features a high level of permeability and welded seams to assure high quality and durability. | Durable and agile, recommended for metal powders, and even handles toner paint. Optimal to use with bridging/caking materials. | Snow‑white filters for the perfectionist – when it is important that white conveyed materials only get in touch with immaculate, white equipment. | Pharmaceuticals and chemical industry champion thanks to its increased chemical resistance. It can be sterilized for 30 minutes at 123 °C / 253 °F. | The biggest filter area to handle extremely fine powders. Rigid and heavy‑duty, works best with materials that are hard to be filtered out with other filter types. |
| Material | Polyethylene | Polyester | Polyethylene | Polyethylene | Stainless steel (316Ti, 316L) | Polyester with PTFE membrane |
| Grade of filtration (minimal particle size) | 0.5 µm | 5 µm | 0.5 µm | 0.5 µm | 5 µm | 0.5 µm |
| Compatibility with vacuum conveyors | All piFLOW® conveyors | piFLOW®p, piFLOW®fc, piFLOW®i, piFLOW®f, piFLOW®t | piFLOW®p, piFLOW®f, piFLOW®t | piFLOW®p, piFLOW®fc, piFLOW®i, piFLOW®f, piFLOW®t | piFLOW®p, piFLOW®fc | All piFLOW® conveyors |
| Industries of application | Suitable for all industries with small particle sizes, including Food, Chemical, Pharma, Additive Manufacturing. | Food, Chemical, Pharma | Food, Chemical, Pharma, Additive Manufacturing | Pharma, Food, Chemical, Additive Manufacturing | Pharma, Food, Chemical | Suitable for all industries with small particle sizes, including Food, Chemical, Pharma, Additive Manufacturing. |
| Material particle types | Powders, fine powders, ultrafine powders, bridging materials | Granules*, tablets, powders**, fine powders***, bridging materials | Powders, fine powders, ultrafine powders, bridging materials | Powders, fine powders, ultrafine powders, bridging materials | Granules, tablets, powders, fine powders, bridging materials | Extremely fine and free‑flowing powders |
| Can it be used with hygroscopic or caking/bridging materials? | Yes | Yes | Yes | Yes | Yes | No |
| ATEX (antistatic properties) | Yes | Yes | Yes | No | Yes | Yes |
| Filter area |
1500 cm² / 1.61 ft² More variants are coming soon |
600, 900, 1400, or 2340 cm² / 0.65, 0.97, 1.51, 2.52 ft² | 800, 1400, 2500, or 4500 cm² / 0.86, 1.51, 2.69, 4.84 ft² | 310, 800, 1400, 2500, or 4500 cm² / 0.33, 0.86, 1.51, 2.69, 4.84 ft² | 800, 1500, 2500, 5000 cm² / 0.86, 1.61, 2.69, 5.38 ft² | 400, 800, 3000, 5000, or 10000 cm² / 0.43, 0.86, 3.23, 5.38, 10.76 ft² |
*Granules are powders with particle sizes over 25 µm.
**Powders have a particle size of over 10 µm.
***Fine powders have a particle size of over 5 µm.
Air inlet filters
Air inlet filters prevent atmospheric and air-carried dust and particles from entering the conveying system through the adjustable air inlets of the feed adapters, resulting in contained material transport through the system. At the same time, they prevent the conveyed material from coming out from the feed adapters' adjustable air inlets, e.g., when fluidization is used. When an Air Inlet filter is added to Piab’s feed adapter, it prevents cross-contamination. They are compatible with all Piab feed adapter types and are also recommended when venting holes are used in the vacuum conveying setup. Air inlet filters have a weather hood to increase their lifetime.
Placement of the air inlet filters
In this application example, the material is conveyed from a barrel (1) with a feed wand (2) to a sieve (3), then to a V-blender (7) through a hose (6), and goes further to a silo (10), having a vacuum conveyor on top (9). The (5) air inlet filters are placed on the air inlets of the (4) feed adapters. When an air inlet filter is connected to the feed adapters, a specific (8) Reducer must be applied. Cross-reference tables are available in the respective manuals of the air inlet filters to choose the right elements for your setup. Replacement elements are also available for all air inlet filter types and sizes.
Select the appropriate air inlet filter
Consider the compliance level of your facility. The Standard air inlet filter (carbon steel) is suggested when requirements are lower and non-conductive materials are conveyed. When higher demands apply, such as antistatic properties are needed, or where acid/corrosive resistance is a must, the Antistatic air inlet filter (SS316) is advised.
Compare the options
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| Standard air inlet filter | Antistatic air inlet filter |
Choose Standard when:
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Choose Antistatic when:
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How to use vacuum filters?
The so-called vacuum filters (2) are recommended when there are lower hygienic requirements in the facility and no food requirements or antistatic properties are needed. They are lightweight, made of plastic, and have a filter grade of 5-10 µm.
They may be used where extra venting is required (due to material characteristics or the process setup). One example is to cover the venting hole on transition pieces (3) under the conveyor body (1) when the material is emptied into a silo/hopper (4) or other equipment. In this case, venting is needed to ensure a smoother material transition as the vent evens the pressure.
How to change the filter with Filter Monitoring?
Watch our video to see how quick and easy it is to change a filter on a piFLOW®p with the integrated Filter Monitoring system. This feature streamlines scheduled maintenance by providing real-time insights into filter conditions, ensuring timely interventions. Reduce downtime and enhance productivity, keeping your operations running smoothly and efficiently. Contact us below to learn more!
Do you need a replacement filter?
If you use a vacuum conveyor, remember that filters are consumables and, depending on your industry, will typically need changing somewhere between every 6–12 months (often closer to 6 months in pharma or when handling abrasive powders like ceramics).
To see the exact spare filters and parts for your specific conveyor configuration, register to MyPiab and add your vacuum conveyor’s serial number in MyProducts, then go to MyProducts to view your recommended spares.
Looking for advice?
Not sure which filter fits your application? Describe your challenge and we'll recommend one.