A flexible heater typically consists of a heating element, such as a thin film of metal, sandwiched between two layers of flexible insulating material. The heating element is connected to electrical power, and when the power is turned on, the heating element generates heat. The heat is transferred to the surface that the flexible heater is in contact with, providing a localized heating effect.
The type of heating element used in a flexible heater can vary, but common options include resistive wire, etched foil, and thin-film polymer. The insulating material helps to prevent heat loss and electrical shorting and can also provide physical protection for the heating element.
Flexible heaters can be designed to operate at a specific temperature, using temperature sensors and control circuitry, or can be operated in a simple on/off manner. The flexibility and conformability of flexible heaters make them well-suited for applications where heating is required on irregular or curved surfaces, and where a thin, lightweight heating solution is desired.
The flexibility of these heaters allows for easy installation on irregular or curved surfaces, making them suitable for a wide range of heating requirements. This is extremely important when it comes to the aerospace industry, where components that help operate the equipment are small and compact with little room for anything bigger than a flexible heater to handle.
Usage and Benefits
For the aerospace industry, instrument panels, spacecraft, and satellites experience unique environmental challenges where heating components using convection methods is not always possible. Flexible heaters have become the ideal solution for the aerospace industry for a variety of reasons.
Versatile polyimide heaters for aerospace applications.
They provide efficient and reliable performance in a variety of aerospace applications and can be used for several purposes such as:
- Anti-icing and de-icing of wings, fuselage, engines, and other components to prevent ice build-up and ensure safe operation in cold weather conditions.
- Temperature control of avionics, instruments, and other sensitive electronics to maintain proper functioning and prevent overheating or failure.
- Heating of fuel and oil lines to prevent viscosity changes and ensure proper flow, especially in high-altitude flights.
- Preheating engines, turbines, and other components prior to starting to reduce stress on the components and improve reliability.
Speaking solely on aircraft, flexible heaters are used on the engine and oil sumps to keep the fluids warm during cold temperatures to prevent thickening, on windshields and windows to prevent icing and improve visibility, on cockpit controls to keep critical instruments and controls functioning in cold temperatures, in environmental control systems in order to regulate the temperature and prevent icing of air ducts and ventilation systems, and for fuel and hydraulic lines so they can prevent freezing and maintain fluid flow.
Flexible Heaters for Space Applications
In space applications, flexible heaters are used to maintain temperature control in various components and systems, such as electronic equipment, sensors, and instruments. They are also used to maintain the temperature of fluid lines, battery packs, and other critical components. By using flexible heaters, engineers can ensure that critical components in a spacecraft or other space-based equipment operate within their specified temperature ranges, even in the extreme conditions of space.
- Durability: Flexible heaters are made from durable materials that can withstand harsh conditions and extreme temperatures encountered in space.
- Lightweight: Flexible heaters are lightweight and compact, making them ideal for use in space where weight and volume are major considerations.
- Ease of installation: Flexible heaters can be easily installed in tight spaces and around obstacles, making them ideal for use in spacecraft where access may be limited.
- Energy efficiency: Flexible heaters can be designed to operate at high temperatures with low power consumption, making them energy efficient and ideal for use in space where power is limited.
- Low outgassing: Refers to the release of gases from materials into the surrounding environment, typically vacuum which can occur due to a variety of factors, including exposure to heat and pressure changes. Polyimide flexible heater materials that have low outgassing properties are highly desired for use in space because they emit fewer gases into the surrounding environment, reducing the risk of contamination or interference with sensitive equipment.
Flexible heaters offer several advantages for use in the aerospace industry due to several reasons, such as being thin and lightweight. This makes them ideal for aerospace applications where weight is a critical factor. In regard to conformability, flexible heaters can conform to complex shapes and curves, allowing for easy integration into aerospace systems and components. Flexible heaters are also easy to install, as they can be cut to size and shape, and are often self-adhesive, allowing for quick and simple installation.
Given their versatility, flexible heaters can be used for anti-icing, temperature control, and engine preheating. Their energy efficiency helps to provide localized heating, reducing energy waste compared to other heating methods. In terms of safety and durability, flexible heaters are designed to be safe and reliable, with over-temperature protection and high-temperature insulation to prevent fire hazards. They are typically made with rugged, high-temperature materials, making them durable and suitable for harsh aerospace environments.
Types of Flexible Heaters
Note that in the aerospace industry, two types of flexible heaters are commonly used: silicone rubber heaters and polyimide film heaters. Silicone rubber heaters are made by embedding heating elements in a flexible silicone rubber material, which provides good thermal conductivity, durability, and flexibility. They are used in a variety of applications in aerospace due to their resistance to high temperatures, corrosion, and chemical exposure.
Polyimide film heaters consist of a thin, flexible polyimide film with heating elements etched on one side. They are known for their fast-heating capability, high efficiency, and flexibility, making them ideal for use in aerospace for heating small or complex shapes.
Both silicone rubber heaters and polyimide film heaters can be customized to meet the specific requirements of different aerospace applications.
When selecting the size of flexible heaters for aerospace applications, several factors should be considered, including the size and shape of the surface to be heated, the heating power required for the application, the voltage and current requirements of the heating system, and the environmental conditions and temperature range the heater will be exposed to.
Polyimide/Kapton® Flexible Heaters
The design of a polyimide/Kapton® heater offers dimensional stability, superior tensile strength, and overall improved resilience. Polyimide is also resistant to most chemicals. Based on the material to heat (steel, aluminum, water, oil, plastic, air, etc.), custom-designed and manufactured polyimide flexible heaters offer a low profile and rugged design while maintaining safety by being both abrasion and acid-resistant.
From airplane instrument panels to communication equipment in unmanned spacecraft, these components and machines sometimes require the use of flexible heaters to keep parts from freezing in sub-zero temperatures, remove moisture from semiconductors and circuits, or provide thermal heat transfer solutions. Aerospace manufacturers may want to select Kapton® flexible heaters when designing and manufacturing products and equipment because their features include:
- Lightweight and Thin
- Low Outgassing Characteristics
- Superior Thermal Heat Transfer in Vacuum Environments
- De-icing and Defogging Applications
- Won't Impede Moving Parts
- Radiation, Oil, and Chemical Resistance
Anywhere in the aerospace industry that operates with tight spaces and demanding conditions should consider the benefits of a polyimide/Kapton® heater.
Summary
Flexible heaters are an essential component of the aerospace industry, providing convenient and efficient heating solutions, and they are a versatile and cost-effective alternative to other heating methods. They are preferred in the aerospace industry due to their light weight, thin profile, and ability to conform to complex shapes, making them easy to integrate into aerospace systems and components. It is important to work with an experienced manufacturer such as Epec to ensure that the flexible heater selected is appropriate for the specific aerospace application and meets the required specifications and standards.
