Thermoplastic Concentric Reducer
Solid-Plastic Concentric Reducers for Smooth Inline Diameter Transitions
25mm – 200mm
Size Range
Socket / Butt Weld
Connection
PP / PPH / PVDF
Material
PN 6 / 10 / 16
Pressure
Concentric Reducers for Thermoplastic Pipelines
UNP’s Thermoplastic Concentric Reducer provides a smooth diameter transition between two pipe sections of different sizes — with the pipe centerline maintained through the reduction. The concentric design is standard for vertical runs and most horizontal applications.
Available with socket-weld or butt-weld ends in PP, PPH, PVDF, and ISO.PP. The gentle conical taper minimizes turbulence and pressure drop through the reduction. Wall thickness scales with the larger of the two pipe sizes to maintain pressure rating.
For eccentric (offset) transitions where bottom-of-pipe alignment is critical (e.g., in horizontal sludge or settling lines), eccentric reducers are available on request.
Why Choose This Fitting
- ✓Concentric (symmetric) reduction
- ✓Smooth conical taper (low turbulence)
- ✓Socket weld or butt weld ends
- ✓Wall scales with larger pipe size
- ✓Eccentric option on request
Dimensions, Materials, Testing
Reducer Dimensions
All dimensions in millimeters unless noted.
| Size | Main OD (mm) | Reduced OD (mm) | Length (mm) | Wall Thk (mm) |
|---|---|---|---|---|
| 25 x 20 | 25 | 20 | 30 | 2.3 |
| 32 x 25 | 32 | 25 | 40 | 2.9 |
| 40 x 32 | 40 | 32 | 50 | 3.7 |
| 50 x 32 | 50 | 32 | 60 | 4.6 |
| 50 x 40 | 50 | 40 | 60 | 4.6 |
| 63 x 50 | 63 | 50 | 70 | 5.8 |
| 75 x 50 | 75 | 50 | 85 | 6.8 |
| 90 x 63 | 90 | 63 | 100 | 8.2 |
| 110 x 75 | 110 | 75 | 115 | 10.0 |
| 110 x 90 | 110 | 90 | 115 | 10.0 |
| 160 x 110 | 160 | 110 | 155 | 14.6 |
| 200 x 160 | 200 | 160 | 190 | 18.2 |
Materials of Construction
| Material | Description |
|---|---|
| PP (Polypropylene) | General-purpose, low-cost option for mildly corrosive media at moderate temperatures. |
| PPH (Polypropylene Homopolymer) | Higher mechanical strength than PP — better for pressure service. |
| PVDF (Polyvinylidene Fluoride) | Superior abrasion resistance and high mechanical strength. |
| ISO.PP (Isotactic Polypropylene) | Improved temperature and chemical resistance vs standard PP. |
Connection Types Available
| Connection | Description |
|---|---|
| Socket Weld | Heat-fused socket joints for permanent, leak-tight assemblies. |
| Butt Weld | End-to-end heated fusion for in-line pipe sections. |
| Threaded | Removable threaded fittings for serviceable connections. |
| Flanged | Bolted flange joints for easy disassembly and inspection. |
Testing & Quality
| Test | Standard / Result |
|---|---|
| Hydrostatic Test | BS EN 12266-1 / DIN 8077 / DIN 8078 |
| Visual / Dimensional Inspection | 100% Sampled |
| Pressure Rating | PN 6 / PN 10 / PN 16 (depending on size & material) |
| Temperature Range | 0°C to 80°C (PP) / 0°C to 95°C (PPH) / -40°C to 140°C (PVDF) |
| Certifications | ISO 9001:2015 |
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Order Your Thermoplastic Concentric Reducer
Tell us your main and reduced sizes, material, and connection type — we’ll spec the exact reducer for your line.