Dielectric Ball Valve Insert for Isolated Torque Transfer
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Solution Overview
Problem
Actuated ball valves in water systems, such as aircraft water supply systems, face issues with electrical faults transmitting from the motor to the metal ball shaft, leading to potential electric shocks or arcing, and there is a need for a fall-back drive mechanism in case of motor failure.
Innovation Solution
A dielectric insulating insert is provided between the ball shaft and the electric motor, featuring a plasma electrolytic oxidation (PEO) aluminium coating on an aluminium substrate, with an elastic adhesive layer to ensure torque transfer and prevent backlash.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a metal ball shaft is used to satisfy durability and safety standards, then strength and reliability are improved, but electrical faults can transmit from the motor to the ball shaft causing electric shocks or arcing
Solution Approach 1:
A dielectric insert is introduced as an intermediary component between the metal ball shaft and the electric motor. This insert breaks the conductive path while allowing torque transmission, preventing electrical faults from reaching the metal ball shaft while maintaining mechanical functionality.
Solution Approach 2:
The solution employs a composite structure combining metal components (ball shaft, motor housing) with a dielectric material insert. This composite approach allows simultaneous achievement of mechanical strength from metal and electrical insulation from the dielectric material, resolving the contradiction between conductivity and insulation requirements.
2Object-affected harmful factors
If a dielectric insert is added to prevent electrical fault transmission, then electrical safety is improved, but device complexity increases
Solution Approach 1:
The dielectric insert is designed to perform multiple functions simultaneously: providing electrical insulation to prevent fault transmission, transmitting torque from the motor to the ball shaft, and potentially serving as a sealing element. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity.
3Extent of automation
If the electric motor is used to drive the ball shaft, then automation is improved, but a fall-back drive mechanism is needed in case of motor failure
Solution Approach 1:
The system is designed with dynamic characteristics that allow transition between automated operation (motor-driven) and manual operation (handle-driven). The universal drive mechanism can adapt to different operating modes, providing automation when needed while maintaining manual fallback capability without requiring completely separate drive systems.
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 dielectric insert effectively insulates the electrical components from the water-side metal parts, preventing electrical faults and ensuring safe operation, while also providing a reliable torque transfer mechanism and a manual handle for fallback operation in case of motor failure.
Implementation Method 1
The dielectric coating may comprise a plasma electrolytic oxidation, PEO, aluminium coating on the substrate.
Implementation Method 2
an outer adhesive layer which may be formed of an elastic adhesive
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A dielectric insulating insert arranged to be positioned between a drive shaft and a ball shaft (10) of a motorised ball valve assembly, the insert (20) comprising a body of dielectric material to form an insulating layer (21) and having opposing sides from each of which extends an engagement portion (22, 23) having a non-circular cross-section and configured to engage, respectively, with the drive shaft and the ball shaft in torque transfer engagement.