Flexible Heated Hose With Printed PTC Heater
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Solution Overview
Problem
Aircraft fluid lines are prone to freezing in cold atmospheric conditions, and existing resistance heater technologies require complex external control systems for temperature regulation, complicating precise temperature management.
Innovation Solution
A flexible heated hose assembly for aircraft using a printed PTC heater with multiple layers, including a silicone liner, Aramid fiber braid, and corrosion-resistant steel braid, which self-regulates temperature without the need for external controls, ensuring the hose remains operational between -65°F and +185°F (-53°C and +85°C).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional resistance heater wire technology is used, then heating function is provided, but external control systems are required which complicate temperature regulation
Solution Approach 1:
The PTC heater material inherently self-regulates its temperature through its positive temperature coefficient property. As the temperature increases, the electrical resistance automatically increases, reducing the current and heating effect without requiring external sensors or control circuits. This eliminates the need for temperature sensors, electronic thermostats, and complex control wiring.
Solution Approach 2:
The invention utilizes the temperature-dependent electrical resistance parameter of PTC materials. The resistance changes dynamically with temperature, providing automatic feedback control. This parameter change enables the heater to transition from a high-resistance cold state to a low-resistance heated state, and back again, creating self-regulating thermal cycles.
2Measurement precision
If external control systems are used for temperature regulation, then temperature control is achieved, but the system requires temperature sensors and electronic thermostats
Solution Approach 1:
The PTC heater material inherently self-regulates its temperature through its positive temperature coefficient property. As the temperature increases, the electrical resistance automatically increases, reducing the current and heating effect without requiring external sensors or control circuits. This eliminates the need for temperature sensors, electronic thermostats, and complex control wiring.
3Adaptability or versatility
If flexible hose structure is used, then adaptability is improved, but temperature uniformity and control become more difficult
Solution Approach 1:
The invention uses a flexible printed circuit board (FPC) as the substrate for the PTC heater, allowing the heating element to conform to the flexible hose structure. The FPC maintains structural integrity while bending, ensuring uniform heat distribution across the hose surface regardless of its flexible configuration.
Solution Approach 2:
The heater assembly combines multiple materials including PTC polymer material, flexible printed circuit board, adhesive layers, and protective coatings. This composite structure provides both flexibility for hose adaptation and thermal stability for uniform heating, with each layer contributing specific properties to the overall performance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively prevents fluid lines from freezing by utilizing a self-regulating and self-limiting printed PTC heater, eliminating the need for temperature sensors and electronic thermostats, providing reliable and efficient heating within a wide temperature range.
Implementation Method 1
printed positive temperature co-efficient (PTC) heater
Implementation Method 2
printed positive temperature co-efficient (PTC) heater
Implementation Method 3
first Aramid fiber braid, a third silicone liner, a corrosion resistant steel (CRES) braid, and a second Aramid fiber braid
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A flexible heated hose assembly (100) for an aircraft is provided. The flexible heated hose assembly (100) including: an inner fluid tube (110) enclosing a fluid passageway (108), the inner fluid tube (110) having tubular shape; a first silicone liner (120) located radially outward from the inner fluid tube (110); and a printed positive temperature co-efficient (PTC) heater (130) located radially outward from the first silicone liner (120).