Encapsulated Calorimetric Flow Meter with Thermal Isolation
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Solution Overview
Problem
Current calorimetric flow meters, particularly those made from silicon, are prone to damage and costly, limiting their widespread industrial and medical applications due to lack of robustness and high production costs.
Innovation Solution
A silicon-based integrated circuit calorimetric flow meter with a fluid flow channel, temperature sensing elements, and a heating element, encapsulated in a housing for enhanced accuracy, reliability, and flexibility, allowing for digital control and reduced costs, along with a method of manufacturing that includes gel encapsulation and a lead frame for thermal isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If silicon-based calorimetric flow meters are used, then measurement precision and reliability are improved, but device robustness deteriorates making them prone to damage
Solution Approach 1:
The patent combines silicon integrated circuit sensors with a protective housing structure, creating a composite device that maintains the measurement precision of silicon sensors while adding mechanical robustness through the housing and mounting structure
Solution Approach 2:
The protective housing and mounting structure serve as a cushioning mechanism that protects the fragile silicon sensors from physical damage before damage can occur, allowing the device to be used in more robust applications
2Measurement precision
If silicon-based calorimetric flow meters are manufactured, then measurement accuracy is improved, but production cost increases
Solution Approach 1:
The integrated circuit assembly incorporates the sensors, heating element, and signal processing circuitry in a single self-contained unit, eliminating the need for separate calibration and assembly steps that would increase manufacturing complexity and cost
3Measurement precision
If traditional calorimetric flow meters are used, then measurement functionality is achieved, but device complexity increases reducing ease of operation
Solution Approach 1:
The patent merges the sensing elements, heating element, signal processing circuitry, and microprocessor into a single integrated circuit assembly, simplifying the overall device structure and making it easier to operate while maintaining measurement functionality
Solution Approach 2:
The integrated circuit serves multiple functions simultaneously - sensing temperature, controlling heating, processing signals, and calculating flow rate - which reduces the number of separate components needed and simplifies operation
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 solution provides a robust, cost-effective calorimetric flow meter with improved accuracy and flexibility, suitable for a wide range of applications, by utilizing silicon integrated circuit sensors and encapsulation techniques, reducing the risk of damage and enhancing performance.
Implementation Method 1
a heating element located in between the temperature sensing elements to heat a region of the channel
Implementation Method 2
at least two temperature sensing elements operative to measure the temperature in different regions of the channel
Implementation Method 3
When a fluid flow is present in the tube, heat exchange takes place between the tube and the fluid
Data Source
AI summary
An encapsulated calorimetric flow meter according to the present invention comprises an integrated circuit (104) mounted on a lead frame (102). The integrated circuit has a channel (105) provided in its lower face, the channel being aligned with two holes (103) provided in the lead frame, the holes coinciding with the ends of the channel (105). There are further slots (111) in the lead frame (102) alongside the integrated circuit to thermally isolate it from the rest of the lead frame (102), which acts as a heat sink to keep the entry and exit fluid at ambient temperature. The flow meter is manufactured by mounting the integrated circuit (104) on to a suitable lead frame (102). The assembly of integrated circuit (104) and lead frame (102) is then inverted and blobs of gel (112, 114) are then deposited onto the lead frame (102) covering the holes (103). The assembly is then inserted into a mould (100) and encapsulated within a suitable mould compound. When the assembly is ejected from the mould cavity the gel can be removed and the holes (103) and the channel (105) exposed to facilitate fluid flow into, out of and along the channel (105).