Calibrated Polyurethane Tube Medifly PU153 (Ø 1.5×3 mm, 98 ShA)

1. Purpose and Operating Principle

The tube is made from high-quality polyether-based polyurethane (Polyether Polyurethane) with a hardness of 98 ShA / 52 ShD. Thanks to its strong, flexible wall and precision-calibrated outer diameter (3 mm), it provides a leak-tight connection with push-in quick-release fittings and is resistant to repeated bending and hydrolysis.

2. Technical Specifications

⚠️ Unconfirmed data / check with our manager:

• Exact weight of a 100 m coil (estimated ~0.65 kg, needs confirmation against the datasheet).
• Pressure derating factor at temperatures above +40°C (recalculate using Medifly’s temperature table).

3. Design Features

Decoding the Medifly PU153 part number:

Key design features:

1. Polyether base. Unlike cheaper polyester-based polyurethane, this tube has high resistance to hydrolysis, bacteria, and mold, making it suitable for water and humid air.
2. Excellent low-temperature flexibility. Retains elasticity down to −40°C without cracking or stress-cracking effects.
3. Metric marking. Every 50 cm, the tube wall is printed with the size and batch number, simplifying cutting and measuring during installation.

4. Installation Recommendations

• Use a dedicated end-face tube cutter (guillotine). Cut the tube strictly at a 90° angle — pliers or scissors deform the 3 mm outer diameter, causing leaks at the push-in fitting.
• Choose the correct fitting type: push-in/push-fit fittings with external sealing for the 3 mm diameter, or miniature compression fittings with a union nut.
• Do not allow a bend radius smaller than 8 mm — a tighter bend can crease the wall and narrow the 1.5 mm bore.
• When fitting BSPP (G) threaded connectors, use a face seal ring (no PTFE tape).
• When fitting BSPT (R) threaded connectors, apply anaerobic thread sealant or PTFE tape.

5. Analogues and Comparison

Cross-references (always verify outer and inner diameters before substituting):

Comparison within the Medifly line:

• PU153 (98 ShA polyurethane) — high working pressure (20 bar), maximum flexibility, abrasion resistance.
• PE153 (PELD polyethylene) — lower working pressure (10 bar), chemical inertness, but less flexibility and more prone to kinking with frequent bending.
• PA1124 (polyamide/nylon) — high rigidity, pressure up to 44 bar, but a significantly larger minimum bend radius.

6. Common Mistakes

• Using the tube in hot water above +60°C — the polyurethane softens and working pressure drops significantly.
• Mounting on a barbed (“christmas tree”) fitting without a clamp — for 3 mm tubing, a push-in fitting or compression nut is required, not just a barbed push-on connection.
• Using standard polyester-based polyurethane in a wet environment — this type degrades through hydrolysis, whereas PU153 (Polyether) is specifically protected against this.
• Cutting with ordinary pliers — a crushed 3 mm end doesn’t seat tightly in the fitting, leading to air leaks.

7. Practical Applications

• Dental and medical equipment — water and air supply lines in medical unit hoses.
• Miniature pneumatics and automation — connecting micro-cylinders, sensors, and valve manifolds.
• Robotics — moving cable bundles on manipulators, thanks to bend and abrasion resistance.
• Laboratory and analytical instruments — transporting non-aggressive liquids and gases.
• Dosing and spraying systems — supplying lubricants, varnishes, and coating materials.

8. Expert Opinion

Vitali Boluchevski, Lead Engineer at Acvatron SRL (18 years of experience):

“The Medifly PU153 polyurethane tube, 3×1.5 mm, is the quality standard for micro-pneumatics and dental equipment. The main advantage of the Polyether series is its resistance to constant contact with water and condensate: the tube doesn’t cloud, doesn’t lose strength, and doesn’t crack over time. For installation into push-in fittings, I recommend using only a professional guillotine-style tube cutter — ordinary pliers almost always leave a non-sealing end at such a small diameter.”

9. Frequently Asked Questions

1. Can the PU153 tube be used for drinking water? Yes, Medifly’s polyether-based polyurethane raw material complies with European and US food contact regulations Reg. (EC) 1935/2004, Reg. (UE) 10/2011, and FDA CFR 21.

2. How does polyether-based polyurethane differ from standard (polyester) polyurethane? Polyether-based polyurethane is resistant to water, moisture, microorganisms, and hydrolysis. Standard polyester-based polyurethane loses strength and degrades over time in a humid environment.

3. Does the tube fit 3 mm Festo / SMC push-in fittings? Yes, the Medifly PU153 tube has a calibrated outer diameter of 3.0 mm with tolerance per ISO/TS 11619, guaranteeing compatibility with push-in fittings from all major brands.

4. What’s the maximum pressure the tube can withstand at room temperature? Working pressure is 20 bar, and burst pressure is 80 bar (at +23°C).