Device for measuring and regulating a volume flow in a ventilation pipe
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Solution Overview
Problem
Conventional volume flow sensors in ventilation pipes are influenced by pipe geometry, leading to installation challenges and measuring errors, as they require separate mounting and are sensitive to straight or curved pipe sections.
Innovation Solution
A device integrating a motor-controllable ventilation flap with a thermal anemometer, where the sensor surface is placed on the drive housing or as a separate module, allowing for reliable volume flow regulation and measurement, independent of pipe geometry, using a turbulence generation element to ensure optimal measurement conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional volume flow sensors are mounted separately in the ventilation pipe, then the sensor can be positioned at the center of the pipe cross section, but the installation complexity and outlay increase
Solution Approach 1:
The sensor mounting is integrated with the ventilation flap mounting, combining two separate functions into a single structural unit. This eliminates the need for separate mounting operations and reduces installation complexity while maintaining the ability to position the sensor at the pipe center for accurate measurements
2Device complexity
If pressure measurement cells are used to determine volume flow, then the measurement can be performed with integrated sensors, but the measurement range is limited and low flow velocities cannot be measured accurately
Solution Approach 1:
The patent changes the measurement parameter from pressure difference (which has limited range) to temperature difference (which provides superior measurement range and sensitivity). Thermal anemometers can accurately measure both low and high flow velocities by detecting the cooling effect on a heated sensor element, overcoming the limitations of pressure-based measurement cells
3Ease of operation
If the sensor is mounted directly in the ventilation pipe, then the installation is simplified, but the sensor signals are influenced by the geometry of the line profile leading to measuring errors
Solution Approach 1:
A flow straightening element is installed upstream of the sensor to pre-condition the flow before it reaches the measurement point. This element eliminates the influence of pipe geometry and flow disturbances from bends or fittings, ensuring that the sensor receives uniform, axial flow regardless of the upstream pipe configuration, thereby maintaining measurement accuracy while allowing direct mounting in the ventilation pipe
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 simplifies the installation and operation of ventilation systems by providing accurate volume flow measurement and regulation, regardless of pipe geometry, reducing measuring errors and installation complexity.
Implementation Method 1
thermal anemometers (that is to say, anemometers based on temperature measurement, to be precise on the determination of the degree of cooling of a heating element which is dependent on the flow velocity of the medium)
Data Source
AI summary
A device for measuring a volume flow in a ventilation pipe (1) comprises a sensor element (13) disposed on the mounting (8) and configured as a thermal anemometer. Upstream of the sensor element is a turbulence-generating element, which is configured and disposed at a distance from the sensor surface (18.1) such that highly turbulent flow is generated in the region of the sensor surface in a targeted manner. Downstream of the sensor surface is a flow element (20), which widens in the cross-section thereof in the flow direction (L), wherein starting from a height level of the sensor surface a height is reached that is greater than the height of the break-away edge (17.1) opposite the sensor surface.