The Automatic Water Injection Degassing Machine is the dedicated working fluid injection station for heat pipe production lines — the machine that determines how precisely each heat pipe receives its working fluid charge. Injection accuracy: ±0.05% of the set volume (the tightest specification in Cooling-Thermal's degassing machine range), achieved by a positive displacement pump that meters fluid in precise volumetric increments independent of supply pressure variation. Injection needle: Ø0.9mm × 100mm long — sized for the Ø3–Ø6mm degassing end geometry of standard heat pipes. Volume range: 0–2.5ml covers the full working fluid fill range for Ø4–Ø10mm diameter heat pipes at standard fill ratios. Pipe OD: Ø4–Ø10mm. Degassing end length: 80–500mm pipe length, ≤80mm degassing end.
Key Specifications
| Specification | Value |
| Pipe OD | Ø4 – Ø10 mm |
| Pipe Length / Degassing End | 80 – 500 mm / ≤ 80 mm |
| Water Volume Range | 0 – 2.5 ml |
| Water Volume Accuracy | ±0.05% |
| Injection Pump Type | Positive displacement |
| Injection Needle | Ø0.9 mm × 100 mm long |
| Working fluids | Ultra-pure water (standard) |
Why ±0.05% Matters — Working Fluid Fill Ratio and Heat Pipe Thermal Performance
Research consistently shows that heat pipe thermal performance peaks at a working fluid fill ratio of approximately 30% of internal void volume — with performance degrading measurably both above and below this optimum. At a fill volume of 1.0ml (typical for a Ø6mm × 200mm heat pipe), ±0.05% accuracy means the actual fill varies by ±0.0005ml from the set point — a variation so small it has no measurable effect on thermal performance. By contrast, a ±1% accuracy pump introduces ±0.01ml variation at the same fill volume — enough to shift the fill ratio away from optimum by ~1%, with corresponding thermal resistance increase. For thermal solution products where performance specifications are guaranteed, the fill machine's accuracy is one of the three manufacturing parameters (alongside wick thickness and vacuum depth) that determine whether the finished heat pipe meets its thermal spec.
Production Line Position — Where This Machine Fits in the Heat Pipe Manufacturing Sequence
The heat pipe degassing station sits at Step 5 in the complete 11-step heat pipe production sequence — after working fluid injection and before welding/sealing at Step 6. It is the quality gate that determines the internal vacuum quality and working fluid charge accuracy of every heat pipe that proceeds to welding, hot pressing, bending, and performance testing. A heat pipe that leaves the degassing station with incorrect NCG level or incorrect working fluid volume cannot be corrected at any downstream step.
What Is an Automatic Water Injection Degassing Machine -- and Why It Is Not a Simple Liquid Dispenser
The Automatic Water Injection Degassing Machine is the dedicated working fluid injection station in sintered wick copper heat pipe production. Its function is to inject a precisely metered volume of ultra-pure water into each heat pipe that has been degassed and is held under vacuum -- filling the sintered wick's pore structure with working fluid at the correct fill ratio (approximately 30% of total internal void volume for sintered wick heat pipes) before the open degassing end is sealed.
This machine must simultaneously solve three distinct engineering problems that a general-purpose liquid dispenser cannot address: first, it must maintain the vacuum in the heat pipe cavity throughout the injection cycle so that no non-condensable gas (NCG) re-enters before sealing; second, it must deliver an injection volume accurate to plus or minus 0.05 percent regardless of supply line pressure variation, fluid temperature drift, or cavity back-pressure changes between tubes; and third, it must prevent the injected working fluid from being partially re-evacuated by the vacuum system -- the suck-back problem -- before the fill cycle is complete and the heat pipe is sealed. Cooling-Thermal's M5 solves all three simultaneously through a positive displacement pump, a Ø0.9mm injection needle sized for standard heat pipe degassing end geometry, and ice-water temperature stabilisation maintained throughout the full fill cycle.
