MEMS Sensor Chip for Medium-Independent Flow Rate Determination
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Solution Overview
Problem
Existing methods for determining volume and mass flow in pipes rely on material properties of the medium, such as viscosity and density, which must be known, limiting their medium-independent measurement capabilities.
Innovation Solution
A method and device utilizing a MEMS sensor chip with a measuring channel to determine density and viscosity, combined with a differential pressure measurement through a coordinated aperture and measuring channel, allowing for medium-independent volume and mass flow determination by using the pressure drop and properties detected by the MEMS sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If differential pressure measurement with orifices is used, then volume flow can be measured, but the measurement depends on material properties of the medium (viscosity, density) which must be known
Solution Approach 1:
The patent combines differential pressure measurement with MEMS-based viscosity and density sensing in a single integrated system. The MEMS sensor chip includes a measuring channel that simultaneously experiences pressure drop and fluid property interactions, allowing concurrent measurement of multiple parameters without requiring separate measurement systems for each property.
Solution Approach 2:
The system uses the fluid itself to provide the necessary measurement information. The MEMS sensor detects viscosity and density directly from the flowing medium, eliminating the need for external calibration or pre-knowledge of material properties. The fluid's own properties are measured as it passes through the sensor channel.
2Adaptability or versatility
If MEMS sensor chip with measuring channel is used to determine density and viscosity, then medium-independent flow measurement is enabled, but the measuring channel must be coordinated with aperture to ensure proper flow ratio
Solution Approach 1:
The flow path is segmented into two parallel channels: the aperture channel for differential pressure measurement and the MEMS measuring channel for fluid property detection. This segmentation allows each channel to serve its specific measurement function while maintaining a controlled flow distribution ratio between them.
Solution Approach 2:
The measuring channel of the MEMS sensor is designed with specific local characteristics (cross-sectional area, length, geometry) that differ from the aperture channel. This local quality differentiation ensures that the flow ratio remains within the optimal range (1:20 to 1:500) for accurate viscosity measurement while maintaining overall system functionality.
3Measurement precision
If the flow ratio between measuring channel and aperture is controlled to be less than 1:20, then accurate viscosity measurement is achieved, but the aperture must be precisely coordinated with the measuring channel
Solution Approach 1:
The aperture and measuring channel are designed and positioned in advance during the manufacturing process to achieve the target flow ratio. The geometric dimensions and relative positioning are predetermined based on the required flow distribution, allowing the system to be manufactured with the necessary precision without requiring complex post-manufacturing adjustment.
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
Enables accurate and independent measurement of volume and mass flow in pipes without requiring prior knowledge of the medium's properties, enhancing measurement reliability and versatility.
Implementation Method 1
a density and/or a viscosity of the fluid is determined by means of a MEMS sensor chip, with a measuring channel of the MEMS sensor chip for determining the density and/or the viscosity of the fluid is at least partially flowed through by the medium flowing in the pipe, and by means of a detected pressure drop | p2-p1 |
Implementation Method 2
a differential pressure measuring arrangement for detecting a pressure drop | p2-p1 | above the aperture inserted into the tube and the measuring channel of the MEMS sensor chip
Data Source
Figure 1
AI summary
The invention relates to a method for determining a volumetric and/or mass flow rate of a medium (M) flowing in a tube (20), wherein a density and/or a viscosity of the fluid (F) is/are determined by means of a MEMS sensor chip (30), wherein the medium (M) flowing in the tube (20) at least partially flows through a measuring channel (31) of the MEMS sensor chip (30) to determine the density and/or the viscosity of the fluid (F), and wherein the volumetric and/or mass flow rate of the medium (M) is determined regardless of the medium by means of a detected pressure drop (│p2-p1│) over the measuring channel (31) of the MEMS sensor chip (30) and the density and/or viscosity determined by the MEMS sensor (30).