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5710 Flatiron Parkway, Suite A |
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Boulder, CO 80301 |
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Call : (303) 443-2262 |
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FAX : (303) 443-1821 |
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Graphite Fiber Thermal Strap Assemblies (GFTS) |
 Custom Designed GFTS Assemblies
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Technology Applications, Inc. designs and fabricates custom graphite fiber thermal strap assemblies for heat transfer from power dissipation components such as cryocooler compressors, electronics, or radar electronics that dissipate anywhere from forty watts to several hundreds of watts and require an efficient, lightweight carbon graphite thermal conductor for transferring heat to the heat rejection radiator.
Our GFTS assemblies use K1100 graphite fiber bundles, a continuous fiber with a thermal conductivity of 1100 W/m-K. Each fiber bundle consists of 20,000 individual carbon fibers wrapped with a fine polyester cord for support. These graphite fibers have 2.75 times the thermal conductivity of copper and ¼ the density. Therefore, on a per unit mass basis, they are 11 times more weight efficient than copper, and over six times more weight efficient than aluminum.
GFTS assemblies demonstrate thermal efficiencies up to 92%, yielding a 65 to 80 percent weight savings over aluminum or copper straps for the same conductance. These straps have sufficient flexibility to accommodate installation and alignment tolerances, relative structural movements due to vibration and thermal
contractions, and some limited bending motion.
Technology Applications, Inc. can perform a complete system analysis to determine the heat load of components, and the routing geometries required for your system. If your system requires just one GFTS or hundreds, each assembly must pass quality checks and undergo thermal conductance tests after construction to verify system compliance.
GFTS Features & Benefits:
- In house design and fabrication of custom GFTS assemblies to meet customer specifications.
- Thermal conductance is tested before they ship to the customer.
- Low loss attachment end fittings.
- Up to 92% thermal efficiency.
- 65% weight savings over aluminum.
- 80% weight savings over copper.
- 275% more thermal conductance than copper.
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| Comparison of Thermal Conductivity
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| Standard GFTS Assemblies
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Technology Applications, Inc. produces graphite fiber thermal straps on a custom designed and fabricated basis. However, due to customer requests for a simplified GFTS unit (shown in figure 1) for "universal" applications, we produce two different standard GFTS assemblies that can be configured to any length required. These assemblies were designed to accommodate situations where a custom tailored GFTS is not required for the customer application.
Our standard GFTS assemblies are constructed with the same materials and craftsmanship as our custom designed assemblies. Each assembly must pass quality checks and undergo thermal conductance tests after construction to verify compliance.
1 Row Strap:
- Approximate length (configured to any length): 28.5 cm
- Approximate width (measured at the end fittings): 5 cm
- Conductance (varies based on length): 0.11 W/K*
- Approximate weight: 50 grams
- 6061 aluminum end fittings
- 20 fiber bundles aligned in 1 row
An equivalent aluminum conductor with the same thermal conductance would have a cross section of 1.5 cm2 and weigh 125 grams.
2 Row Strap:
- Approximate length (configured to any length): 28.5 cm
- Approximate width (measured at the end fittings): 5 cm
- Conductance (varies based on length): 0.20 W/K*
- Approximate weight: 80 grams
- 6061 aluminum end fittings
- 40 fiber bundles aligned in 2 rows (20 bundles per row)
An equivalent aluminum conductor with the same thermal conductance would have a cross section of 2.6 cm2 and weigh 245 grams.
*Due to the manufacturing process of graphite fiber bundles there could be slight positive or negative variations in overall bundle conductance. Thermal conductance tested at room temperature.
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Figure 1
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1 & 2 Row Straps
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| Visible Camera System GFTS Assembly |
This GFTS was designed to accommodate tactical cryocoolers with a 10,000 hour operating lifetime, making them a low cost alternative for many ground, airborne, and space-based tactical infrared surveillance systems that require vibration control and effective heat rejection.
These straps successfully passed rigorous shock and vibration qualification tests for launch vehicle loads. They have demonstrated high thermal and weight efficiency and is sufficiently developed for heat transfer from critical components.
The GFTS developed for this system exceeded all of its requirements, enabling the use of low-cost alternative cryocoolers for many aerospace applications. At the cryocooler drive frequency, it demonstrated more than 40 dB reduction in the axial direction and between 31 and 37 dB in the two radial directions; the next four harmonics were reduced an average of 22 dB. The GFTS assembly successfully attenuated vibration forces and maintained the cryocooler expander well within its recommended operating temperature.
- Conductance: 0.35 W/K (center to ends).
- Dissipates heat from thermal electric cooler.
- Weight: 50 grams
- Passed shock, vibration, and stiffness compliance tests for interceptor missile launch environment.
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| Standard GFTS Assembly for Evaluation |
Technology Applications, Inc. produces graphite fiber thermal straps on a custom designed and fabricated basis. However, due to customer requests for a standard GFTS unit for evaluation, TAI has designed a simplified arch shaped GFTS unit based on an existing application. This simplified GFTS assembly is designed primarily for customers to experience and evaluate the effectiveness of graphite fibers as an efficient heat removal system.
- Approximate length: 5.5 cm
- Approximate width: 4 cm
- Approximate height: 3 cm
- Conductance: 0.24 W/K*
- Approximate Weight: 26 g
- 6061 aluminum end fittings
- Approximate fiber cross-section of 0.1884 cm2
- 12 fiber bundles aligned in 1 row
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 GFTS Data Sheet & Questionnaire:
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