Thermal Flowmeter Sensor Spacers for Uniform Solder Layer Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing thermal flow meters face challenges in achieving consistent and reproducible sensor production with uniform solder layer thickness, leading to variations in heating current and measurement accuracy, which are costly and labor-intensive to address.
Innovation Solution
A sensor design for thermal flow meters that uses spacers made of hardened sintering paste to maintain a defined distance between the sensor element and the sensor cup, ensuring consistent thermal connection and reducing solder layer thickness fluctuations, achieved through a method involving spacer attachment, solder application, and controlled heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If embossing is used to create a defined distance between the sensor element and sensor cup base, then the distance is ensured, but the processing effort increases and the embossing die wears
Solution Approach 1:
The patent introduces spacers as intermediary elements between the sensor element and the sensor cup base. These spacers are made from a hardenable paste that is applied in a defined quantity, hardens to a predetermined height, and maintains a constant distance without requiring embossing operations. This mediator approach eliminates the need for complex embossing processes and die wear issues while achieving the same distance control function.
Solution Approach 2:
The patent changes the physical state of the spacer material from a soft paste to a hardened solid through a hardening process. This parameter change (from paste to hardened state) allows the material to maintain its shape and height, providing stable spacing without requiring mechanical embossing. The hardening process transforms the material properties to achieve the desired dimensional stability.
2Productivity
If the solder layer thickness varies between sensors, then production is simpler, but measurement accuracy decreases due to variations in heating current
Solution Approach 1:
The patent applies spacers to the sensor element before the soldering process. This preliminary action establishes the correct distance and orientation of the sensor element relative to the sensor cup base before soldering occurs. By pre-positioning the sensor element with spacers, the solder layer thickness becomes less critical, allowing for simpler production while maintaining measurement accuracy through consistent thermal coupling geometry.
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
This approach ensures a uniform temperature transition with minimal fluctuations between sensors, enhancing measurement accuracy and reducing production effort and costs by avoiding complex processing steps.
Implementation Method 1
the at least three spacers having a hardened sintering paste
Implementation Method 2
a layer of solder which is set up to thermally connect the sensor element to the bottom of the cup
Implementation Method 3
Melting the solder layer and pressing the sensor element with the spacers against the bottom of the cup
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a sensor (10) of a thermal flowmeter, to a thermal flowmeter, and to a method for producing such a sensor (10). The sensor (10) has a sensor cup (11), spacers (15) guaranteeing a defined distance of a sensor element (30) from a cup base (13) of the sensor cup such that a good temperature transfer between the sensor (10) and a medium flowing around the sensor is ensured. Thermal contact between the cup base (13) and the sensor element (30) is established by means of a solder layer (20).