Case AP-2 — Vehicle Refrigeration Capillary Tube
Hardware: LF Series Mass-Flow Tester + LT-KZ02 Claw-Type External-Clamp Quick Connector
| Specification | Value |
|---|---|
| Test Pressure (Nominal) | 700 kPa (range: 650–750 kPa) |
| Accept Flow Window | 3.42–3.58 L·min⁻¹ |
| Total Cycle Time | 17 s |
| Detection Method | Mass flow rate |
| Connector Pressure Rating | 50 bar (5,000 kPa) |
Problem
Automotive refrigerant capillary tubes operate at high pressure (650–750 kPa) with bore diameters under 3 mm. Tube-to-tube bore diameter differences of ±0.05 mm produce flow-rate differences far larger than any seal leak — making pressure-decay testing unreliable as a go/no-go criterion for this geometry.
Solution
The LF Series mass-flow tester measures actual volumetric flow rate through the tube under steady-state pressurization. The LT-KZ02 stainless-steel claw-type connector is rated to 50 bar (5,000 kPa) — 7× the test pressure — with a grip range of 6–52 mm OD.
Result
- 17-second cycle with higher discrimination accuracy than pressure-decay
- Accept window 3.42–3.58 L·min⁻¹ provides positive tube-integrity confirmation
- Zero tube-end deformation over 500,000+ production cycles