Needle Valve Nozzle With Electroactive Polymer Pressure Sensing
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Solution Overview
Problem
Existing needle valve nozzles lack a simple and efficient mechanism for pressure-based control and monitoring, particularly in high-temperature environments like hot runner systems for injection molding, where existing technologies do not effectively integrate electroactive polymers for both actuation and sensing functions.
Innovation Solution
A needle valve nozzle with an electroactive polymer drive assembly that acts as both an actuator and a pressure sensor, utilizing changes in electrical properties under load to control the valve pin movement and monitor fluid pressure, integrated within a housing with a cooling system to withstand high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If an electroactive polymer is used as an actuator to move the valve needle, then the valve can be controlled electrically, but the device cannot simultaneously detect fluid pressure without additional components
Solution Approach 1:
The electroactive polymer is designed to perform dual functions: as an actuator that moves the valve needle when voltage is applied, and as a sensor that detects fluid pressure through changes in its electrical properties. This multi-functionality eliminates the need for separate actuation and sensing components, resolving the contradiction between automated control and pressure detection capability.
Solution Approach 2:
The patent combines the actuator and sensor functions into a single integrated electroactive polymer element. The polymer's ability to both contract under voltage and change electrical properties under pressure allows it to serve as both the driving mechanism and the detection element, merging previously separate functions into one component.
2Reliability
If separate actuator and sensor components are used, then each function can be optimized, but the device complexity increases
Solution Approach 1:
The electroactive polymer serves as both actuator and sensor, eliminating the need for separate components. This reduces device complexity while maintaining reliable actuation and sensing functions through the polymer's inherent dual capabilities.
Solution Approach 2:
By merging the actuator and sensor into a single electroactive polymer element, the patent reduces the number of components and simplifies the overall device structure while preserving both actuation and pressure detection functions.
3Adaptability or versatility
If the electroactive polymer is exposed to high temperatures in hot runner systems, then it can be used in injection molding applications, but the polymer's performance and structural integrity may deteriorate
Solution Approach 1:
A housing with integrated cooling channels acts as an intermediary between the high-temperature environment and the electroactive polymer. The cooling system mediates the thermal exposure, allowing the polymer to operate in hot runner systems while maintaining its performance and structural integrity through active temperature management.
Solution Approach 2:
The patent changes the thermal environment of the electroactive polymer by introducing active cooling, thereby modifying the temperature parameter from high (hot runner conditions) to controlled (polymer operating range), enabling the polymer to function in previously unsuitable high-temperature applications.
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
Enables precise control and monitoring of fluid pressure in hot runner systems, ensuring consistent pressure across multiple cavities and improving operational efficiency by integrating electroactive polymers as both actuators and sensors, while maintaining structural integrity under high temperatures.
Implementation Method 1
An electroactive polymer is capable of converting electrical and mechanical energy. When a voltage is applied to the electroactive polymer, it expands or contracts, depending on the polymer design, and thereby moves the valve pin.
Implementation Method 2
the electroactive polymer also has the effect of changing electrical properties under load, e.g., emitting an electrical voltage and thus acting as a pressure sensor
Implementation Method 3
housing with a cooling system to withstand high temperatures
Data Source
Figure 1~2
Figure 3a~3c
AI summary
A needle valve nozzle (1) comprising a nozzle (10) and a valve needle (12) having a needle tip (13) at a first end for closing the nozzle (10). The valve needle (12) has a polymer drive assembly (20) at a second end remote from the needle tip (13) comprising an electroactive polymer. The electroactive polymer expands under an applied electrical voltage and acts as an actuator (27), and the electroactive polymer changes its electrical properties under load and thereby acts as a pressure sensor (26). According to the invention, the at least one polymer drive assembly (20) presses the needle tip (13) into the nozzle (10) under an electrical voltage provided as a control signal by a control device (30) as a drive, while the needle tip (13) slides out of the nozzle (10) in the de-energized state without a control signal.A pressure of a fluid acting on the needle tip (13) that is present at the nozzle (10) leads to a change in electrical properties at the pressure sensor (26), which is fed as a sensor signal to the control device (30) for evaluation, where the sensor signal is processed into a value for a fluid pressure prevailing at the needle tip (13). A housing for accommodating the at least one polymer drive arrangement (20), wherein the housing comprises a cooling system and wherein the housing is adjustable in the axial direction of the shut-off needle.