The internal surface profile of a PTFE hose — smooth or convoluted — is the single biggest determinant of flow performance, flexibility, cleanability, and cost. Smooth bore and convoluted are not interchangeable constructions. Choosing the wrong one for your application compromises either performance or the budget without any compensating benefit.
Smooth Bore PTFE Hose
Smooth bore hose features a uniform, uninterrupted internal surface with a coefficient of friction of approximately 0.04–0.10. The bore is fully self-draining and can be cleaned with pig tools or CIP chemical cycles without fluid retention.
- 20–30% better flow efficiency versus equivalent convoluted bore.
- Fully self-draining — no fluid retained between uses.
- Full CIP/SIP cleanability — pharmaceutical and food-grade standard choice.
- Lower particle generation — smooth surface eliminates entrapment and release of particles.
- Wider range of standard end fittings available from stock.
Convoluted (Corrugated) Bore PTFE Hose
Convoluted bore hose has accordion-fold corrugations moulded into the PTFE inner. The profile allows tighter bending than smooth bore without kinking or collapsing the liner — typically 30–40% tighter minimum bend radius.
- 30–40% tighter minimum bend radius versus smooth bore of the same OD.
- Superior vibration absorption — corrugations damp axial stress and shock loads.
- Typically 20–30% lower cost than smooth bore equivalent.
- Good vacuum resistance — corrugated profile resists collapse under negative pressure.
- Preferred for dynamic applications where the hose flexes in service.
Side-by-Side Comparison
| Property | Smooth Bore | Convoluted Bore |
|---|---|---|
| Flow Efficiency | 20–30% better | Baseline |
| Minimum Bend Radius | Larger | 30–40% tighter |
| Cleanability / CIP | Excellent — self-draining | Fluid retention in valleys |
| Vibration Isolation | Limited | Excellent |
| Relative Cost | Higher | 20–30% lower |
| Pharmaceutical Suitability | Standard choice | Not recommended for CIP processes |
| Dynamic Applications | Possible, not ideal | Preferred construction |
Material Properties Are Identical
Both smooth and convoluted bore PTFE hose share the same material properties: temperature range (–65°C to +260°C), chemical resistance (virtually universal), and FDA 21 CFR 177.1550 compliance where virgin PTFE is specified. The difference is entirely structural — not material. You do not get better or worse chemical resistance from one profile versus the other.