Nordson Screen Changer Alternatives: A Technical Comparison
The most common reasons process engineers look for a Nordson screen changer alternative are: total cost of ownership (including hydraulic control unit and maintenance), lead time for replacement parts, and application fit for high-contamination recycling streams. The technically equivalent alternatives in the continuous self-cleaning category are the Cofit AP Series — which operates without a hydraulic control unit — and, for high-contamination applications above 3–4% by weight, the Cofit Gorillabelt continuous belt system.
Why Process Engineers Look for a Nordson Screen Changer Alternative
Nordson Corporation — through its BKG brand — is one of the largest suppliers of screen changers and melt filtration equipment globally. BKG products are well-established in the industry and installed on thousands of extrusion lines worldwide. The question is not whether Nordson screen changers work — they do. The question is whether a specific Nordson product is the optimal solution for a specific application, and whether alternatives offer better fit on the parameters that matter most for that application.
Process engineers typically begin evaluating alternatives for one of four reasons. The first is hydraulic infrastructure cost: many Nordson continuous screen changer models require a dedicated hydraulic control unit for the cleaning or screen-change actuation mechanism. This adds capital cost, installation complexity, and an ongoing maintenance requirement that some plants — particularly those retrofitting existing lines — want to avoid.
The second reason is parts availability and lead time. As a large multinational, Nordson serves a broad customer base and spare parts for older or less common models can have extended lead times. For operations running 24/7, a screen changer component that takes weeks to arrive is a supply chain risk.
The third reason is application fit for high-contamination recycling. Post-consumer recyclate streams — with contamination at 3–8% by weight, as documented by AMI Consulting — require specific filtration technology. If the installed Nordson product is a self-cleaning cartridge design, it may not handle contamination levels above 3–4% by weight indefinitely, and a belt-based alternative becomes the correct technical choice.
The fourth reason is simply competitive specification: OEMs and converters evaluating new lines compare multiple suppliers on technical and commercial parameters before selecting equipment. This article focuses on the technical parameters.
Technical Comparison: Nordson BKG vs Cofit AP Series vs Cofit Gorillabelt
The table below compares published technical parameters across the three systems. All Nordson data is sourced from publicly available BKG product documentation and Nordson technical publications. Where specifications vary by model, the range is indicated.
| Parameter | NORDSON | COFIT | ||
|---|---|---|---|---|
| BKG HiCon continuous self-cleaning series |
BKG hydraulic discontinuous series |
AP Series continuous self-cleaning |
Gorillabelt continuous belt |
|
| Filtration type | Continuous self-cleaning | Discontinuous hydraulic | Continuous self-cleaning | Continuous belt advance |
| Production stop for screen change | No | Brief flow interruption | No | No |
| Melt pressure stability | Stable during cycle | Spike at changeover | ±2% during cleaning | Stable |
| Hydraulic control unit required | Yes — most models | Yes | No — integrated mechanism | Yes — belt drive unit |
| Filtration fineness | To application spec | To application spec | Down to 3 μm | Belt mesh to spec |
| Max contamination level | ~2–4% by weight | ~1–2% by weight | Up to ~3–4% by weight | Up to 10% by weight |
| Post-consumer recyclate (>30%) | Depends on model | Not suitable | Up to ~30% PCR | 100% PCR capable |
| Max operating pressure | Up to 500 bar (model-dependent) | Up to 400 bar | Up to 500 bar | Up to 210 bar |
| Max operating temperature | Up to 350°C | Up to 350°C | Up to 350°C | Up to 350°C |
| Cleaning cycle trigger | ΔP or timer | Manual / operator | ΔP or timer — automated | ΔP or continuous advance |
Nordson BKG data sourced from publicly available product documentation. Cofit data from engineering specifications. Specifications vary by model and configuration — contact suppliers directly for application-specific data.
The Hydraulic Control Unit: A Meaningful Difference
One of the most practically significant differences between Nordson BKG continuous screen changers and the Cofit AP Series is the hydraulic infrastructure requirement. Most Nordson BKG continuous models use hydraulic actuation for the screen cleaning or exchange mechanism — which requires a dedicated hydraulic power unit (HPU), hydraulic lines, and the associated maintenance programme.
The Cofit AP Series self-cleaning mechanism is integrated within the filter housing and does not require any external hydraulic unit. This is not a minor specification difference — it has direct consequences for installation cost, floor space, and ongoing maintenance overhead.
For a new line installation, the HPU cost and installation are typically absorbed into the project budget without issue. For a retrofit on an existing line — where floor space is constrained, utility connections are fixed, and the project timeline is short — the absence of a hydraulic requirement in the AP Series is frequently the deciding factor. “We selected the AP because we could install it in a weekend without touching any utilities,” notes a maintenance engineer at a European cast film converter. “The hydraulic alternative would have required a three-week shutdown to route lines and qualify the HPU.”
What the Hydraulic Unit Costs Over Time
Beyond installation, hydraulic systems require ongoing maintenance: fluid changes, seal replacement, filter servicing, and periodic pump inspection. The Society of Plastics Engineers (SPE) estimates hydraulic system maintenance on extrusion auxiliary equipment at 2–4% of capital cost per year. On a screen changer HPU with a capital cost of €15,000–25,000, that is €300–1,000 per year in maintenance overhead — not including unplanned downtime from hydraulic failures.
Hydraulic fluid contamination of the polymer melt — caused by seal failures in the screen changer housing — is a low-frequency but high-consequence risk in food-contact and medical-grade extrusion applications. Systems that eliminate hydraulic actuation in the melt zone remove this risk entirely.
How Much Is Your Current Screen Changer Costing You in Downtime?
Enter your throughput, screen change frequency, and shift schedule. The Cofit Productivity Savings Calculator shows your monthly output loss and annual revenue impact in under two minutes.
When Nordson BKG and When Cofit: An Objective Framework
Both Nordson BKG and Cofit produce technically capable continuous screen changers. The selection framework is not “which is better” — it is “which fits this application better.” The following criteria are the parameters on which the two suppliers genuinely differentiate.
- Your organisation already has established Nordson service agreements and parts inventory
- The line is already equipped with a hydraulic power unit that can serve the screen changer
- You are specifying a complete Nordson melt delivery system (gear pump, screen changer, die adapter) as an integrated package
- Your OEM has a Nordson-qualified installation standard and you prefer to stay within it
- You need a specific Nordson model configuration that is not replicated by other suppliers
- You are retrofitting an existing line and want to avoid hydraulic infrastructure installation
- Floor space or utility connections make an external HPU impractical
- You require filtration fineness down to 3 μm with continuous operation and no hydraulic risk in the melt zone
- Application is food-contact or medical-grade where hydraulic fluid contamination risk must be eliminated
- Total cost of ownership — including HPU capital, installation, and maintenance — is a primary evaluation criterion
- You want direct access to engineering support without multilevel service organisation
When Neither Self-Cleaning System Is the Right Answer
If your polymer stream contains post-consumer recyclate above 30% content — or any stream with hard particle contamination above 3–4% by weight — neither the Nordson BKG continuous self-cleaning range nor the Cofit AP Series is the technically appropriate solution. Self-cleaning systems have a cleaning rate limit: above this contamination threshold, particle accumulation outpaces the cleaning cycle capacity of any cartridge-based design.
For these applications, continuous belt filtration is the correct technology. The Cofit Gorillabelt advances fresh filtration belt through the melt zone without any cleaning cycle, handling contamination up to 10% by weight continuously. This is a category of product that Nordson BKG does not currently offer in its standard range — making it a genuine differentiator rather than a specification trade-off between equivalent systems.
Practical Considerations When Switching Screen Changer Suppliers
Replacing a screen changer — whether from Nordson or any other supplier — involves three engineering checkpoints that determine whether a direct substitution is feasible or whether additional modifications are required.
1. Melt channel geometry and flange connections
The screen changer mounts between the extruder barrel outlet and the die adapter. The inlet and outlet flange dimensions, bolt pattern, and melt channel bore diameter must match the existing line geometry — or adapter flanges must be machined. In most cases, a process engineer from the replacement supplier reviews the existing line drawings before any equipment is specified, confirming fit or identifying the required adapter work.
2. Filtration area and throughput capacity
The replacement screen changer must provide equivalent or greater filtration area at the line’s throughput rate. Undersizing the filtration area relative to throughput raises baseline ΔP above operational limits and accelerates screen saturation. According to Plastics Technology, incorrect filtration area sizing is among the top five causes of screen changer underperformance on replacement installations. The replacement supplier should confirm filtration area specification against the line’s throughput, polymer viscosity, and required filtration fineness.
For a complete guide to diagnosing and solving melt pressure instability after a screen changer replacement, see melt pressure instability: causes and solutions →
3. Control system integration
Continuous screen changers require control signals — typically a ΔP trigger from upstream pressure transducers and, optionally, integration with the line’s SCADA or PLC system for alarm management and cycle logging. The Cofit AP Series uses a standalone control interface that does not require PLC integration for basic operation, simplifying installation on lines where control system access is restricted. Full PLC integration is available for lines where centralised alarm management is required.
Cofit Screen Changers: Technical Specifications
Two product families for the full melt filtration spectrum — from fine-filtration film and fiber applications to high-contamination post-consumer recycling.
- Filtration fineness: down to 3 μm
- Melt pressure stability: ±2% during cleaning cycle
- No external hydraulic control unit required
- Max pressure: 500 bar · Max temperature: 350°C
- Throughput range: 5–2,000 kg/h
- Applications: film, fiber, sheet, coating, compounding
- Max contamination: up to 10% by weight
- No cleaning cycle — no saturation limit
- Handles metal, glass, foil, paper, cross-linked polymer
- Max pressure: 210 bar · Max temperature: 350°C
- Applications: post-consumer recycling, industrial waste streams
- No equivalent in the Nordson BKG standard range
For the complete technical guide to screen changer types: Screen Changers for Plastic Extrusion → · Continuous vs Discontinuous →
Frequently Asked Questions
In most cases, yes — with a flange adaptation review. The AP Series installs in the same position in the extrusion line (between extruder barrel outlet and die adapter) and performs the same function as a Nordson BKG continuous screen changer. The key mechanical checkpoint is the inlet and outlet flange geometry: bolt pattern, flange diameter, and melt channel bore must match or be adapted to the existing line. A Cofit process engineer reviews the existing line drawings before specifying any replacement equipment to confirm fit or identify required adapter work. The absence of a hydraulic power unit requirement in the AP Series typically simplifies the installation relative to hydraulic-actuated Nordson models.
The most significant operational difference is the cleaning mechanism and its hydraulic infrastructure requirement. Most Nordson BKG continuous screen changer models use hydraulic actuation, requiring a dedicated hydraulic power unit (HPU). The Cofit AP Series uses a patented integrated self-cleaning mechanism that operates without any external hydraulic unit — reducing installation complexity and eliminating the hydraulic maintenance programme and the risk of hydraulic fluid contamination in the melt zone. Both systems deliver continuous filtration with stable melt pressure; the difference is in the infrastructure required to achieve it. Filtration fineness for the AP Series reaches down to 3 μm, comparable to Nordson BKG continuous models.
Nordson BKG’s standard product range focuses primarily on self-cleaning cartridge designs. For post-consumer recycling applications with contamination above 3–4% by weight — where self-cleaning systems reach their cleaning rate capacity — Cofit offers the Gorillabelt continuous belt screen changer, which advances fresh filtration belt through the melt zone without any cleaning cycle. The Gorillabelt handles contamination up to 10% by weight, including metal fragments, aluminium foil, glass, and paper fibres, and is capable of running 100% post-consumer recyclate streams. This is a differentiated product category rather than a direct model-for-model comparison.
A like-for-like screen changer replacement on an existing line — where flange geometry is confirmed and no additional civil or utility work is required — typically takes one planned maintenance weekend. The AP Series does not require hydraulic line routing or HPU commissioning, which is the step that most extends the installation timeline for hydraulic-actuated replacements. The full installation sequence is: flange adapter confirmation (pre-installation), mechanical installation, control signal connection (ΔP trigger from existing upstream transducer), function test, and production startup. Cofit engineers provide direct technical support throughout the installation process.
Cofit manufactures its screen changers at its facility in Cerro Maggiore (Milano), Italy, and holds standard spare parts in stock for its current product range. For European customers, parts are typically available with shorter lead times than for large multinational suppliers, where standard parts are often stocked regionally but non-standard or older-model components may require factory order. Cofit’s smaller product range and direct manufacturing model means that parts procurement goes directly to the engineering team rather than through a multi-level service organisation. For customers in specific regions, lead time should be confirmed directly with the Cofit sales team for the specific parts required.
Sources and References
- Nordson BKG — product documentation and technical publications (publicly available, nordsonpolymerprocessing.com)
- Plastics Technology — extrusion downtime cost benchmarks ($200–$500/line-hour); screen changer sizing guidelines
- AMI Consulting — post-consumer recyclate contamination data (3–8% by weight)
- Society of Plastics Engineers (SPE) — hydraulic system maintenance cost on extrusion auxiliary equipment (2–4% of capital cost/year)
- Cofit International engineering data — AP Series specifications (±2% melt pressure, down to 3 μm filtration fineness, 500 bar, 350°C); Gorillabelt specifications (up to 10% contamination by weight)
Evaluating a Screen Changer Replacement? Start with the Engineering.
Cofit engineers work directly with OEMs and converters to assess application fit, confirm line geometry, and specify the right continuous filtration solution — without commercial pressure. Request a technical alignment or calculate your current downtime cost first.
Cofit deals with research, engineering, manufacture and distribution of automatic and continuous screen changers for post-consumer and post-industrial recycling materials too.
Contact us to upgrade your extrusion system, ask us for more info about any product or service.