Flow Sensor with Partial Encapsulation for Mechanical Stability
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Solution Overview
Problem
Existing flow sensors face mechanical sensitivity and contamination issues due to thin substrates, leading to incorrect measurements, and previous solutions do not ensure ideal flow around the sensor element.
Innovation Solution
A flow sensor design featuring a rigid, electrically conductive carrier part with a sensor element and stable encapsulation that allows unhindered flow around the sensor element, with areas on top and bottom not covered by the encapsulation and leading edges on both sides to minimize mechanical sensitivity and contamination, ensuring optimal flow guidance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If thin substrates are used for flow sensors, then manufacturing precision and sensor sensitivity are improved, but mechanical stability deteriorates and contamination resistance worsens
Solution Approach 1:
The flow sensor is divided into two functional parts: a thin sensor chip for measurement and a separate housing for mechanical support. The sensor chip contains the thin substrate with sensor windings, while the housing provides structural stability and protection, resolving the contradiction between thin substrate requirements and mechanical stability needs
Solution Approach 2:
The thin sensor chip is nested within the housing structure, with the sensor chip positioned inside the housing in a receiving area. This nesting arrangement allows the thin substrate to maintain its manufacturing precision while the surrounding housing provides the necessary mechanical stability and contamination resistance
2Manufacturing precision
If thin substrates are used for flow sensors, then manufacturing precision is improved, but contamination resistance deteriorates
Solution Approach 1:
The flow sensor is divided into a sensor chip and housing, with the housing acting as a protective barrier that prevents contamination from reaching the thin substrate while maintaining manufacturing precision
Solution Approach 2:
The sensor chip is nested within the housing, which provides a protective environment that shields the thin substrate from contamination while allowing the sensor to maintain its precise manufacturing characteristics
3Stability of the object's composition
If encapsulation surrounds the sensor element, then mechanical stability is improved, but flow characteristics around the sensor deteriorate
Solution Approach 1:
The housing provides full encapsulation and mechanical stability in most areas, but strategically leaves the front area of the sensor chip exposed to maintain ideal flow characteristics. This local differentiation allows both mechanical stability and flow measurement reliability to coexist
Solution Approach 2:
Instead of complete encapsulation, the housing provides partial encapsulation that stops before covering the front area of the sensor chip. This partial action maintains the necessary mechanical stability while preserving the flow characteristics needed for reliable measurements
4Stability of the object's composition
If complete encapsulation is used, then mechanical stability and contamination protection are improved, but flow characteristics around the sensor deteriorate
Solution Approach 1:
The housing provides complete encapsulation for mechanical stability and contamination protection in most areas, but creates a local exception at the front area where the sensor chip remains exposed to ensure ideal flow characteristics for precise measurements
Solution Approach 2:
The encapsulation is applied partially rather than completely, stopping before covering the front area of the sensor chip. This partial encapsulation maintains mechanical stability and contamination protection while preserving flow measurement precision
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 design provides increased mechanical stability, prevents dirt deposition, and ensures accurate mass flow measurements by allowing unobstructed flow around the sensor element, minimizing the influence of inflow direction and angle.
Implementation Method 1
the sensor element comprising a plate-shaped carrier substrate on which at least one temperature sensor and a heating element are arranged
Implementation Method 2
areas on the top and bottom of the sensor element not being covered by the encapsulation and allowing the flow to be measured to flow around unhindered
Data Source
Figure 1
Figure 2
Figure 3~4a
AI summary
The flow sensor has a sensor element (2) connected with a fixed, electrical conductive carrier part over electrical conductive connections. The sensor element comprises a plate-like carrier substrate on which a temperature sensor and a heating element are arranged. A stable encapsulation (3) partially surrounds the sensor element and the carrier part in a form-fit manner. Regions on an upper side and a lower side of the sensor element are not covered by the encapsulation and circulated by a to-be measured stream (S). The encapsulation is formed of filled epoxy material. The electrical conductive connections are formed as bond connections. The carrier substrate is made of glass, zirconium oxide and low temperature cofired ceramics.