Combined Fluid Pressure and Temperature Sensor Diaphragm Integration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing combined fluid pressure and temperature sensors face limitations in response time, environmental compatibility, and manufacturing cost, particularly in measuring pressures up to 6.5 psia to 1,000 psia and temperatures from -40°C to 125°C, with existing solutions either having slow response times or being prone to corrosion.
Innovation Solution
A combined pressure and temperature sensor design featuring a variable capacitor with a flexible diaphragm and a discrete SMT NTC thermistor on the diaphragm surface, protected by a thin polymer layer, along with a fluid flow diffuser to enhance fluid flow and accuracy, positioned to minimize thermal mass and maximize environmental resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the thermistor is coated onto the exposed face of the diaphragm, then the temperature sensor can be integrated with the pressure sensor, but the response time is slow and environmental compatibility is reduced
Solution Approach 1:
The thermistor is positioned on the rear face of the diaphragm rather than the exposed face, utilizing the other side of the diaphragm surface. This dimensional change allows the temperature sensor to be integrated with the pressure sensor structure while avoiding direct exposure to fluid media that would slow response time and reduce environmental compatibility.
Solution Approach 2:
The diaphragm itself serves as an intermediary thermal conduction path between the fluid media and the thermistor. By positioning the thermistor on the rear face, the diaphragm mediates heat transfer from the fluid to the temperature sensor, providing both integration and protected positioning that maintains fast response time.
2Ease of manufacture
If the thermistor is disposed within the fluid receiving port or beyond the port, then manufacturing cost is reduced and assembly is easier, but the sensor becomes more susceptible to corrosion and environmental damage
Solution Approach 1:
The thermistor is nested within the housing structure on the rear face of the diaphragm, positioned within the sealed chamber rather than exposed to external environment. This nested positioning provides protection from corrosive fluid media while maintaining integration with the pressure sensing diaphragm, achieving both ease of manufacture and environmental resistance.
3Object-affected harmful factors
If a protective layer is added over the thermistor to improve environmental compatibility, then corrosion resistance increases, but response time may be slowed due to additional thermal mass
Solution Approach 1:
The thermistor is extracted from direct exposure to fluid media and positioned on the rear face of the diaphragm within the sealed chamber. This extraction eliminates the need for additional protective layers that would add thermal mass, as the diaphragm itself provides sufficient thermal conduction while the thermistor remains protected from corrosive environments.
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, low-cost sensor with improved response time and environmental compatibility, maintaining sensitivity and accuracy across a wide range of fluid pressures and temperatures, while being easier to manufacture and assemble.
Implementation Method 1
a variable capacitor mounted in a fluid chamber having a thin ceramic diaphragm exposed to the fluid so that a change in fluid pressure causes concomitant changes in the position of the diaphragm to thereby cause change in the capacitance of the capacitor
Implementation Method 2
a flexible diaphragm and a discrete SMT NTC thermistor on the diaphragm surface
Implementation Method 3
a discrete SMT NTC thermistor on the diaphragm surface, protected by a thin polymer layer
Implementation Method 4
a discrete SMT NTC thermistor
Implementation Method 5
protected by a thin polymer layer
Data Source
Figure 1
Figure 2
Figure 3~5
AI summary
A combined fluid pressure transducer and temperature sensor (10) has a housing (12) containing a variable capacitor (14) having a rigid substrate (14a) and attached flexible diaphragm (14b) in sealed, spaced apart relation. The capacitor is mounted in the housing so that the outer face surface of the diaphragm is exposed to a fluid pressure chamber (12k). A temperature responsive sensor element (28) is disposed on the outer face surface of the diaphragm and covered by a thin protective layer. A fluid flow diffuser (30) is disposed in the fluid pressure port (12b) for directing fluid flow across the temperature sensor.