Fan Motor Pressure Sensing for Flow Rate Measurement

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Solution Overview

Problem

Existing methods for determining volumetric or mass flow rates in fans require external pressure sensors and hoses, which are cumbersome to install and not feasible in all scenarios due to space or robustness concerns, making them impractical and expensive.

Innovation Solution

Integrate a pressure sensor system and speed detection system within the electric motor to measure actual pressure differences and rotational speed, using a bulkhead to prevent pressure equalization, allowing for quantitative determination of flow rates without external sensors or hoses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If external pressure sensors and hoses are used to determine flow rates, then measurement accuracy is improved, but device complexity and installation effort increase significantly

Engineering Contradiction:
Improveflow rate measurement accuracyVSAvoidinstallation complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines the pressure sensing function with existing motor components by forming first and second areas within the motor housing that are naturally exposed to different pressure zones (inlet and outlet sides). This eliminates the need for separate external pressure sensors and their associated wiring, while maintaining accurate flow rate measurement capability through differential pressure detection between these integrated areas.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The motor housing is designed to serve multiple functions: it not only houses the motor components but also provides integrated pressure sensing areas for flow measurement. The first and second areas within the motor housing act as both structural elements and measurement zones, eliminating the need for dedicated external sensing components and reducing overall system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Ease of operation

If pressure sensor systems are integrated into the motor, then installation effort is reduced, but pressure equalization between measurement areas may occur

Engineering Contradiction:
Improveinstallation easeVSAvoidpressure difference measurement reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The motor housing is segmented into distinct first and second areas that are spatially separated and positioned to expose them to different pressure zones. This segmentation prevents pressure equalization between the areas while maintaining their integration within the motor housing, ensuring reliable differential pressure measurement without requiring external hoses or complex sealing arrangements.

Inventive Principle:
Principle #1Segmentation

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 determination of mass or volume flow rates with minimal installation effort by utilizing pressure and speed measurements within the motor, eliminating the need for external sensors and hoses.

Implementation Method 1

the pressure sensor system is configured to determine an actual pressure difference between a first area and a second area

Methodology Applied
Scientific EffectPressure difference measurement:

Implementation Method 2

the speed determination system is configured to determine an actual rotational speed of the impeller

Methodology Applied
Scientific EffectRotational speed detection:

Implementation Method 3

the bulkhead prevents or at least significantly reduces pressure equalization between the first and second areas

Methodology Applied
Scientific EffectPressure containment: Physical Containment

Implementation Method 4

the evaluation unit is configured to determine a mass flow rate and/or a volume flow rate of the medium based on the actual pressure difference, the actual rotational speed and a pressure characteristic of the fan

Methodology Applied
Scientific EffectFlow rate determination from pressure and speed:

Data Source

PatentEP3997342B1Ventilator and method for determining a flow of media moved by the ventilator
Publication Date: 2026.03.04 ZIEHL ABEGG AG
  • EP3997342B1 patent drawingFigure 1
  • EP3997342B1 patent drawingFigure 2
  • EP3997342B1 patent drawingFigure 3

AI summary

The invention relates to a ventilator, by means of which a volumetric flow and/or a mass flow of a medium moved by the ventilator (1) can be determined. The ventilator comprises an electric motor (2) and an impeller (3) driven by the electric motor (2). The impeller (3) moves a gaseous medium from an inflow side (5) to an outflow side (7) in a flow of media. The ventilator additionally comprises a pressure sensor system, a rotational speed ascertaining system, and an analysis unit. The pressure sensor system is designed to ascertain an actual pressure difference (Δp*) between a first region (10) and a second region (13), wherein the first region (10) and/or the second region (13) is/are formed in the electric motor (2), and a pressure (pA) is present in the first region (10), said pressure corresponding to a pressure (p1) present on the inflow side, and a pressure (pB) is present in the second region (13), said pressure corresponding to a pressure (p2) present on the outflow side. The rotational speed ascertaining system is designed to ascertain the actual rotational speed (n) of the impeller (3). Finally, the analysis unit is designed to quantitatively determine a mass flow and/or a volumetric flow of the medium on the basis of the actual pressure difference (Δp*), the actual rotational speed (n), and a pressure characteristic of the ventilator (1). The invention additionally relates to an electric motor for the ventilator and to a corresponding method.