No piping system is complete without protection against contamination. Weld beads left from installation, corrosion residues or solids in the medium can damage pumps, valves and heat exchangers and cause expensive plant downtime.
Industriefabrik Schneider GmbH manufactures industrial filters for almost any application — from food and chemicals through energy and water to oil & gas and mechanical engineering. Manufacture is individual, to PED, AD 2000 and EN 1090, for nominal sizes up to DN 1200 and pressure ratings up to PN 400.
Four basic types form the backbone of the filter portfolio: simplex strainers, basket strainers, duplex strainers and pot strainers. This article places them in context and shows when each type is the right choice.
More articles of interest: To read in more depth how a duplex strainer allows operation to continue without stopping production, see our article Cleaning without stopping production – duplex and changeover filters. Everything about matching screen inserts and retrofit solutions can be found under Replacement screens & screen inserts – retrofit also for other makes.
Basket strainers
The classic for reliable permanent protection
The basket strainer type SKF is the standard solution when piping, vessels, pumps and valves need permanent protection against contamination. The welded design with flanged connection to DIN EN 1092-1 and a large-area stainless steel screen insert provides high operational reliability and long service intervals.
Features:
- Nominal sizes DN 50 to DN 1000 (high-pressure version SKF-H up to PN 400 to DIN EN 1333)
- Body in steel P235GH (1.0345) or stainless steel 1.4571, pickled and passivated
- Filter element with screen in stainless steel 1.4401
- Suitable for liquids, gases and viscous media
Available as an option:
- Heating jacket to prevent viscous media from solidifying
- Quick-release closure for tool-free cleaning
- Differential pressure indicator to monitor the degree of fouling
- Bursting disc, three-point feet, cover lifting and swivelling device
Simplex strainers
The economical solution for standard applications
Where uninterrupted filtration is not required, the simplex strainer type EF offers an economical and robust alternative. The welded design follows the same quality and material standards as the basket strainer.
Features:
- Nominal sizes DN 50 to DN 500, pressure ratings PN 6 to PN 40
- Body in steel P235GH (1.0345) or stainless steel 1.4571
- Filter element in stainless steel with individual mesh size
- Also available as an angle filter variant with 90° connection — saves an
- additional pipe bend in the line
- Optionally with heating jacket, differential pressure indicator and quick-release closure
The simplex strainer is suitable wherever a short, planned interruption of operation for filter cleaning is acceptable — in bypass lines or non-critical process sections, for example. Compared with the duplex strainer it is the structurally simpler and more economical solution.
Duplex strainers
Filtration without interrupting operation
Some processes must not stand still — not even for filter cleaning. That is exactly what the changeover duplex strainer type DF is designed for: via a changeover unit with butterfly valves or ball valves, one filter element can be cleaned or replaced while the other continues to filter — nominal sizes DN 50 to DN 300, pressure ratings PN 6 to PN 40, in steel or stainless steel, changeover manual or motorised.
How this changeover mechanism works in detail, and why it is in such demand in the continuous process industry, is explained at length in our article Cleaning without stopping production – duplex and changeover filters.
Pot strainers
Compact, corrosion-resistant, cleaned without tools
For smaller nominal sizes and confined installation situations, the pot strainer type PSA offers an economical and compact alternative to basket and simplex strainers. The deep-drawn body, made entirely of stainless steel, makes it particularly resistant to aggressive media.
Features:
- Nominal sizes DN 15 to DN 100
- Type PSA: aseptic clamp connection with wing nut to DIN 32676, up to PN 10 — no tools needed to change the screen insert
- Body in stainless steel 1.4571, support basket and fine screen in stainless steel 1.4301
- Venting socket in the cover and drain socket in the base as standard
- Connections: flange, female/male thread, weld ends or dairy pipe union
- Options: differential pressure indicator, ball valves for quick venting and draining, feet
The pot strainer is the preferred choice where space is tight, where screens have to be changed frequently, or where particularly low weight matters — in mobile plant equipment or when retrofitting existing lines, for example.
An overview of the filter types
| Filter type | Nominal size | Operation interrupted for cleaning | Special feature |
| Basket strainer | DN 50–1000 (high pressure up to PN 400) | Yes | Large volume, for high flow rates |
| Simplex strainer | DN 50–500 | Yes | Economical, also as an angle filter |
| Duplex strainer | DN 50–300 | No – changeover during operation | For uninterrupted processes |
| Pot strainer | DN 15–100 | Yes | Compact, light, tool-free change |
Optional accessories: magnetic rods, differential pressure indicator & more
All four filter types can be fitted with additional equipment beyond the basic design. These options are not filter types in their own right but extensions that make sense depending on the application:
Magnetic rods (often associated with the term “magnetic filter”) — are fitted additionally into the screen insert of a simplex strainer, basket strainer, duplex strainer or pot strainer and separate ferromagnetic particles such as iron, steel chips or magnetite that a normal screen alone does not reliably retain.
Other common extensions:
- Differential pressure indicator — monitors the degree of fouling of the screen insert and shows when cleaning is due
- Heating jacket — prevents viscous media from solidifying in the filter body
- Quick-release closure — allows tool-free access to the screen insert for faster maintenance
- Feet and mounting accessories — for free-standing installation without additional support
Which extension makes sense depends on the medium, the process environment and the maintenance intervals of the plant — Industriefabrik Schneider GmbH advises individually and equips each filter type to suit the application.
In brief: if the plant needs continuous operation without downtime, the duplex strainer is the choice. For small nominal sizes and confined spaces the pot strainer is the more compact option. For large volume flows and standard applications, basket and simplex strainers are the proven basis.
Industriefabrik Schneider GmbH advises independently of manufacturer and designs every filter individually to the respective process requirement — from the standard solution to a special design for unusual nominal sizes, pressures or media.
Conclusion
Filter construction is detail work. Whether basket strainer, simplex strainer, duplex strainer or pot strainer — each type has its own field of application, and the right choice determines the operational reliability and maintenance effort of the whole plant. Industriefabrik Schneider GmbH manufactures all four filter types in its own workshop in Großzöberitz, individually to customer requirement, tested to PED and AD 2000.
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