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Custom Heat Pipes
A heat pipe is a simple device that can transfer large quantities of heat over fairly long distances at nearly a constant temperature. A heat pipe is typically a sealed slender copper tube containing a wick structure attached on its inner surface and a small amount of working fluid such as water at the saturation state. The fluid absorbs heat and vaporizes at hot spot and condenses and releases heat at cooler spots. As the process goes on, heat is quickly dissipated from one section to its entire length.
Because a heat pipe has no moving parts, it is a highly reliable device with demonstrated lifespan of over 20 years. The reliability depends on the manufacturing process and the purity of the materials. At MyHeatSinks, our custom heat pipes are 100% individually tested to ensure functionalities and reliability.
Heat pipes are initially manufactured in round shapes with diameters ranged from 4mm to 8mm and lengths ranged from 80mm to 500mm. To meet geometric requirements in different applications, heat pipes can ben flattened, bent or made into specific shape. Flattening and bending will have impacts on the thermal performance and reduce the cooling efficiency. But by following process guidelines, the reduction in performance can be predicted and controlled.
Heat Pipe Dimensions
| Diameter ØD | 4 mm | 5 mm | 6 mm | 8 mm | 10 mm |
|---|---|---|---|---|---|
| Length L | 80-600 mm | 80-600 mm | 80-600 mm | 80-600 mm | 80-600 mm |
| Length L1 | 1-3 mm | 2-4 mm | 3-5 mm | 4-7 mm | 5-8 mm |
| Length L2 | 7-9 mm | 8-10 mm | 9-11 mm | 11-13 mm | 13-15 mm |
Bending of Heat Pipes
| Diameter | Minimum R | Suggested R | Minimum Bending Angle | Suggested Bending Angle |
|---|---|---|---|---|
| 4 mm | 9 mm | 12 mm | 90 ° | 120 ° |
| 5 mm | 12 mm | 15 mm | 90 ° | 120 ° |
| 6 mm | 14 mm | 18 mm | 90 ° | 120 ° |
| 8 mm | 20 mm | 24 mm | 90 ° | 120 ° |
Flattening of Heat Pipes
| Diameter (D) | Thickness (T) | (T) Tolerance | Width (W) | (W) Tolerance |
|---|---|---|---|---|
| Ø4 | 2.0 | +0.05/-0.10 | 5.23 | +/-0.15 |
| Ø4 | 2.5 | +0.05/-0.10 | 4.96 | +/-0.15 |
| Ø4 | 3.0 | +0.05/-0.10 | 4.65 | +/-0.15 |
| Ø5 | 2.0 | +0.05/-0.10 | 6.82 | +/-0.15 |
| Ø5 | 2.5 | +0.05/-0.10 | 6.53 | +/-0.15 |
| Ø5 | 3.0 | +0.05/-0.10 | 6.26 | +/-0.15 |
| Ø5 | 3.5 | +0.05/-0.10 | 5.95 | +/-0.15 |
| Ø5 | 4.0 | +0.05/-0.10 | 5.63 | +/-0.15 |
| Ø6 | 2.0 | +0.05/-0.10 | 8.45 | +/-0.15 |
| Ø6 | 2.5 | +0.05/-0.10 | 8.16 | +/-0.15 |
| Ø6 | 3.0 | +0.05/-0.10 | 7.84 | +/-0.15 |
| Ø6 | 3.5 | +0.05/-0.10 | 7.57 | +/-0.15 |
| Ø6 | 4.0 | +0.05/-0.10 | 7.30 | +/-0.15 |
| Ø8 | 2.0 | +0.05/-0.10 | 11.65 | +/-0.15 |
| Ø8 | 2.5 | +0.05/-0.10 | 11.39 | +/-0.15 |
| Ø8 | 3.0 | +0.05/-0.10 | 11.15 | +/-0.15 |
| Ø8 | 3.5 | +0.05/-0.10 | 10.83 | +/-0.15 |
| Ø8 | 4.0 | +0.05/-0.10 | 10.60 | +/-0.15 |
| Ø8 | 4.5 | +0.05/-0.10 | 10.27 | +/-0.15 |
| Ø8 | 5.0 | +0.05/-0.10 | 10.01 | +/-0.15 |
| Ø8 | 6.0 | +0.05/-0.10 | 9.36 | +/-0.15 |
Heat Transfer Capability
| Heat Pipe Shape | Cross-sectional Dimensions (mm) | Length (mm) | Minimum Bending Radius (mm) | Heat Transfer Rate (L=150mm) (W) |
|---|---|---|---|---|
| Round Pipe | Ø4 | 60-600 | 10 | 30 |
| Round Pipe | Ø5 | 60-600 | 10 | 45 |
| Round Pipe | Ø6 | 60-600 | 12 | 72 |
| Round Pipe | Ø8 | 60-600 | 24 | 120 |
| Flattened Pipe | Ø4 X 2.0T | 60-600 | 10 | 25 |
| Flattened Pipe | Ø5 X 2.0T | 60-600 | 10 | 31 |
| Flattened Pipe | Ø6 X 2.0T | 60-600 | 12 | 42 |
| Flattened Pipe | Ø8 X 2.0T | 60-600 | 25 | 55 |
Reliability Test
| No. | Test Item | Test Conditions | Sampling Ratio | Purpose |
|---|---|---|---|---|
| 1 | High Temp. Aging Test | Ambient Temp. 210 C for 12 hr | 100% | Leakage check & aging |
| 2 | Thermal Response Test | Insert 1/3 – ½ length of pipe into 50°C water. The temp of other end shall rise to standard value in 25 seconds. | 100% | Vacuum & leakage check |
| 3 | Qmax Test | Heating Length = 25-35mm, Test temp = 60°C | 100% | To measure the max. heat transfer rate |
| 4 | Rth Thermal Resistance Test | Fix heat transfer rate and measure temp. difference of heat pipes | >1pcs/2hr | To ensure thermal resistance of each pipe be lower than spec |
| 5 | Accelerated Life Test | 140 C for 1000hr. Performance decrease by less than 7% | By case | To predict life of heat pipe at certain operating temp. |
| 6 | Continuous Life Test | Continuous testing at normal operating conditions | By case | To measure actual life of heat pipe until failure occurs |
| 7 | Thermal Cycling Test | Temp. varies from -30 C to 120 C in 10hr, 600 cycles | By case | To measure performance variation after thermal cycling |