Capacitive Sensor Ferrule Tilt Adjustment
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Solution Overview
Problem
Implantable medical pumps lack effective pressure sensing mechanisms to accurately monitor fluid pressure within the device, which is crucial for reliable drug delivery and refill management, leading to potential malfunctions and inefficiencies.
Innovation Solution
A capacitive pressure sensor is integrated into the implantable medical pump, utilizing a rigid capacitive plate and a deflectable diaphragm to detect changes in fluid pressure, with a housing ferrule and protrusion design that allows for precise orientation and mounting of the plates, enabling consistent capacitance measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a rigid capacitive plate is mounted within a housing ferrule, then the structural stability and orientation precision are improved, but the ability to accommodate manufacturing irregularities and achieve parallel alignment with the diaphragm is worsened
Solution Approach 1:
The support structure is designed with tilting capability, allowing it to dynamically adjust its orientation angle within the housing ferrule. This enables the rigid capacitive plate to be tilted into the desired plane, achieving parallel alignment with the diaphragm capacitive plate despite manufacturing variations. The dynamic adjustment resolves the contradiction by allowing orientation precision to be achieved while accommodating manufacturing irregularities.
Solution Approach 2:
The mounting system is segmented into multiple functional components: the housing ferrule provides the outer structure, the support structure provides tilting capability, and the capacitive plate provides the sensing function. This segmentation allows each component to be optimized independently - the support structure can be designed specifically for tilting adjustment while the capacitive plate maintains its rigid precision, resolving the contradiction between structural stability and adaptability.
2Ease of operation
If the housing ferrule provides a large inner diameter, then the ease of assembly and orientation adjustment are improved, but the precision of positioning the capacitive plate at a specific distance from the diaphragm is worsened
Solution Approach 1:
An assembly tool with a stage is used to perform preliminary positioning of the capacitive plate at the correct distance from the diaphragm before final assembly. The stage provides pre-defined spacing, ensuring that when the support structure is tilted for orientation adjustment, the capacitive plate remains at the precise required distance. This preliminary action resolves the contradiction by establishing position precision before orientation adjustment.
Solution Approach 2:
The assembly tool acts as an intermediary device during the assembly process. It temporarily holds the capacitive plate at the correct position and distance, allowing the support structure to be tilted for orientation adjustment without compromising positioning precision. The intermediary tool enables both ease of operation (tilting adjustment) and manufacturing precision (distance positioning) to be achieved sequentially.
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 pressure sensor effectively monitors fluid pressure within the pump, facilitating accurate drug delivery, refill management, and preventing malfunctions by providing real-time pressure data, thus ensuring reliable operation and patient safety.
Implementation Method 1
The pressure sensor may utilize changing capacitance between two capacitive plates to detect changes in fluid pressure
Data Source
AI summary
The disclosure is directed to a capacitive pressure sensor, and the assembly of a capacitive pressure sensor, that may be used within an implantable medical pump. In one example, a housing ferrule that encloses one capacitive plate and includes at least one protrusion for attaching a support structure of the capacitive plate. The at least one protrusion defines a smaller inner diameter as a reference point for securing the support structure while the ferrule provides a larger inner diameter to allow the support structure to tilt inside the ferrule to orient the capacitive plate into a desired plane. Despite manufacturing irregularities, the capacitive plate can be mounted in the desired plane parallel to another capacitive plate, a diaphragm, mounted to an edge of the ferrule. In another example, an assembly tool provides a stage to orient the capacitive plate and support structure within the ferrule at a desired depth.