Method for controlling a conveyed fluid mass flow by means of differential pressure measurement, and system through which fluid flows
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Solution Overview
Problem
Existing methods for controlling fluid or air mass flow in systems require complex and costly volumetric flow measurement apparatuses, necessitating high fluid velocities and extensive installation, which increases construction complexity and costs, and often compromise accuracy.
Innovation Solution
A method and system utilizing two pressure sensors, one ahead of and one after the fan, to control the fan's rotating speed based on the pressure difference, eliminating the need for flow sensors and allowing for cost-effective, retrofittable, and precise control of fluid or air mass flow without extensive constructive modifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If volumetric flow measurement apparatuses are used to control fluid or air mass flow, then measurement precision is improved, but device complexity and construction costs increase
Solution Approach 1:
The invention extracts the pressure measurement function from the complex volumetric flow measurement apparatus. By using only pressure sensors to measure pressure difference across the fan, the system eliminates the need for complex flow measurement devices while still achieving accurate fluid or air mass flow control through pressure-based calculation.
Solution Approach 2:
The invention replaces mechanical volumetric flow measurement apparatus with a simpler pressure measurement system. Instead of using mechanical flow sensors that require complex installation and maintenance, the system uses pressure sensors to measure pressure difference, which is then used to calculate and control the fluid or air mass flow.
2Measurement precision
If volumetric flow measurement apparatuses are installed to achieve accurate fluid or air mass control, then measurement precision is improved, but installation space and costs increase
Solution Approach 1:
The invention extracts only the essential pressure measurement function from the complex flow measurement apparatus. By placing simple pressure sensors at strategic locations (upstream and downstream of the fan), the system achieves accurate fluid or air mass control without requiring extensive installation space for complex measurement devices.
3Measurement precision
If complex volumetric flow measurement apparatuses are used, then measurement precision is improved, but maintenance requirements increase
Solution Approach 1:
The invention replaces complex mechanical flow measurement apparatus with a simpler pressure-based measurement system. Pressure sensors are more robust and require less maintenance than mechanical flow sensors, while still providing sufficient accuracy for fluid or air mass control when used to measure pressure difference across the fan.
4Measurement precision
If high fluid velocity is required for flow measurement, then measurement precision is improved, but energy consumption increases
Solution Approach 1:
The invention replaces velocity-based flow measurement with pressure-based measurement. Instead of requiring high fluid velocity to obtain accurate flow measurements, the system measures pressure difference across the fan, which can be accurately measured regardless of fluid velocity, thereby reducing energy consumption requirements.
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 simplifies fluid or air mass control by measuring pressure at two locations, reducing installation space and maintenance, enabling precise and cost-effective control of fluid or air mass flow with reduced complexity and costs, while maintaining accuracy.
Implementation Method 1
a first pressure sensor in the flow direction is disposed ahead of the fan, and a second pressure sensor in the flow direction is disposed after the pressure loss portion, and the fan in terms of rotating speed is controlled based on the measured pressure difference between the two pressure sensors
Data Source
AI summary
The invention relates to a method for controlling a conveyed mass flow of fluid or air in a system (1) through which fluid or air flows, comprising: an inlet (2); at least one fan (3) connected downstream of the inlet (2) in the flow direction and having a drive (4); an outlet (5) for conveyed fluid or conveyed air from the fan (3); a pressure loss portion (6) between the fan (3) and the outlet (5); and at least one sensor (7, 8), which is coupled to at least one calculation module (9a, 9b) and to at least one control device (22a, 22b), by means of which the drive (4) of the fan (3) is controlled on the basis of sensor values. A first pressure sensor (7) is provided upstream of the fan (3) in the flow direction and a second pressure sensor (8) is provided downstream of the pressure loss portion (6) in the flow direction, and the speed of the fan (3) is controlled on the basis of the measured pressure difference between the two pressure sensors (7, 8).