Polyurethane Tube SHPI 6×4 mm (US98A6040) – 15 bar, −20…+70 °C

A Problem You’ve Already Faced

• The tube kinks and blocks the flow — cheap PVC stiffens in cold weather and loses flexibility on bending, cutting off the air supply to the tool.
• The tube pulled out of the fitting under pressure — the wall is too soft, the collet won’t grip: at 8–10 bar the joint “pops”.
• Cracks after winter — a PVC tube left outdoors at −10 °C cracks at the first bend in spring.
• Unknown wall thickness — bought a tube with a non-standard wall thickness; the fitting won’t lock or the tube is loose in the collet.
• Not enough length — bought 5 m “by eye”, only to find 8 m were needed at installation.

Choosing the right tube isn’t just about the diameter. Material, wall thickness and working temperature determine whether the tube lasts a season or years.

What Is the SHPI US98A6040 Polyurethane Tube

The US98A6040 is a polyurethane (PU) pneumatic tube from the US98A series by SHPI (Taiwan, ISO 9001, RoHS). Designed for conveying compressed air in pneumatic systems for automation, robotics, pneumatic tools and control circuits.

Part number breakdown — US98A6040:

• US98A — series: SHPI standard-stiffness polyurethane tube;
• 60 — OD × 10 = 6.0 mm;
• 40 — ID × 10 = 4.0 mm.

Why polyurethane outperforms PVC for pneumatics:

• Flexibility is maintained at −20 °C — PVC becomes stiff and brittle at the same temperature
• Abrasion resistance is 4–5 times higher than PVC — important when routing along floors or near moving parts
• Smaller minimum bend radius — the tube does not “remember” its bent shape and springs back straight
• Maximum working temperature up to +70 °C — vs. +60 °C for standard PVC

Technical Specifications

💡 Expert tip: a 6×4 mm tube at 8 bar passes up to 150 l/min — the ideal size for small pneumatic cylinders, airbrushes and control signals. For impact wrenches and spray guns (200–400 l/min) choose 8×5 mm or 10×6.5 mm. Never cut the tube at an angle — the end face must be strictly perpendicular: an angled cut results in incomplete collet grip and a leak.

Comparison with Equivalents

Why Acvatron SRL — 5 Solid Reasons

Original SHPI Tubes with ISO 9001 and RoHS Certificates

Acvatron SRL supplies SHPI tubes with confirmed specifications — not unbranded product with understated ratings. The stated 15 bar working pressure is real, confirmed by the manufacturer’s test records.

Full SHPI Range for a Single System

SHPI PU tubes in 4×2.5, 6×4, 8×5, 10×6.5, 12×8 mm + compatible PC, PL, PT, PB fittings — all in stock at Acvatron SRL. Complete pneumatic line supply from one source.

In Stock at the Chișinău Warehouse

SHPI 6×4 mm tube in 20 m and 100 m reels is permanently in stock at acvatron.md. Collect on the day of payment.

Cut to Length

Need a non-standard length? Specify at the time of order — we cut from the reel as needed. Minimum cut length: 1 m.

Documents for Legal Entities

All items are supplied with accompanying documents. For legal entities — invoice and contract.

Applications

Industrial Automation and Robotics

• Connecting small pneumatic cylinders, grippers and vacuum suction cups
• Control lines for directional valves and positioners
• Pneumatics for robotic assembly cells

Airbrushing and Precision Painting

• Air supply to airbrushes and mini spray guns (consumption up to 150 l/min)
• Restyling and custom paint studios — high tube flexibility is convenient for handheld work

Laboratory and Medical Equipment

• Low-pressure lines for analytical instruments and vacuum systems
• Connecting pneumatic components in medical devices

Auto Service and Diagnostics

• Pneumatic control lines for lifts and wheel alignment rigs
• Connecting pressure sensors and pneumatic relays

Expert Opinion

“The 6×4 mm tube is the smallest size where mistakes are most common: people grab ‘any 6 mm’ off the shelf and wonder why the collet won’t hold. It all comes down to the OD tolerance: SHPI US98A6040 is ±0.1 mm; no-name manufacturers can be ±0.3–0.5 mm. With that kind of deviation the collet either doesn’t fully grip the tube or grips it at an angle — in both cases a leak under pressure is guaranteed. Second point: always cut the tube with a dedicated pneumatic tube cutter or a sharp knife, strictly perpendicular. An angled cut is the most common cause of a leak at the fitting, even with the correct diameter.”

Vitali Bolucevschi, Chief Engineer at Acvatron SRL, 15 years in the industry

How to Choose and Install a Pneumatic Tube Correctly: 5-Step Algorithm

1. Determine the air flow rate — up to 150 l/min: 6×4 mm is sufficient; above 200 l/min: choose 8×5 mm or 10×6.5 mm.
2. Check the system pressure — US98A6040: 15 bar working, ≥45 bar burst.
3. Measure the required length with 20% allowance — routing through conduits, around corners and through clamps uses more length than the straight-line distance.
4. Choose the reel size — up to 10 m: 20 m reel; more than 15 m: 100 m reel is more cost-effective per metre.
5. Fit the connector — perpendicular cut, insert into PC 06-XX until it clicks, verify by pulling with 5–10 kgf.

FAQ

❓ What is the difference between SHPI PU 6×4 mm and PA 6×4 mm?

Both tubes have the same 6×4 mm dimensions but different materials. PU (polyurethane) — softer, more flexible, up to +70 °C and 15 bar, for moving connections. PA (polyamide/nylon) — stiffer, up to +100 °C and 20 bar, for stationary industrial pipelines. Fittings are dimensionally compatible, but PA requires greater insertion force.

❓ Which fitting is compatible with the SHPI 6×4 mm tube?

PC 06-XX and POC 06-XX series fittings (SHPI/XCPC). The «06» code in the fitting part number means 6 mm tube diameter. Examples: PC 06-01 (R1/8″), PC 06-02 (R1/4″), PC 06-G02 (G1/4″). All compatible SHPI fittings are available at Acvatron SRL.

❓ Can the SHPI tube be cut with ordinary scissors?

No — scissors crush the tube wall and produce an angled oval cut. Use a dedicated pneumatic tube cutter or a sharp knife. The cut must be strictly perpendicular and burr-free — only then does the fitting collet guarantee a leak-free seal.

Take the Next Step Right Now

The right tube means a reliable, leak-free pneumatic line with no rework. One call to an engineer before you order saves time and money.

1. 📞 Call us — the Acvatron SRL engineer confirms SHPI 6×4 mm tube is in stock in the required length and selects the compatible fittings.
2. 📋 Request a commercial quote — with part numbers, price per metre/reel and documents. For legal entities — invoice and contract.
3. 🛒 Place your order by phone or at our office — collect from the Chișinău warehouse on the day of payment.

Acvatron SRL — an engineering approach to every sale.