Separator Airflow Direction Control Using Pressure Sensing

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Solution Overview

Problem

Conventional methods for controlling the direction of rotation of electric motors in separators are costly and inefficient, as they rely on phase sequence management, which can vary by installation and require expensive components.

Innovation Solution

A method and system that utilize a pressure sensor to determine the airflow direction in a separator and adjust the phase sequence of the electric motor if necessary, ensuring the correct airflow direction is achieved using a controller and phase sequence changer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional phase sequence management methods are used to control motor rotation direction, then reliable airflow direction control is achieved, but device complexity and cost increase due to expensive components

Engineering Contradiction:
Improveairflow direction controlVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex electrical control systems (phase sequence management, frequency inverters, soft starters) with a simple mechanical sensing approach using a pressure sensor to detect airflow direction. The pressure sensor provides direct feedback about whether the impeller is rotating in the correct direction, eliminating the need for complex electrical control components while maintaining reliable airflow direction control.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system uses the separator's own operating conditions (pressure changes in the flow path) to automatically determine airflow direction. The pressure sensor monitors pressure variations that naturally occur during motor startup and operation, allowing the system to self-diagnose rotation direction without external control equipment. This self-service approach simplifies the control system while maintaining reliability.

Inventive Principle:
Principle #25Self-service

2Reliability

If phase sequence switching components are installed to manage motor rotation direction, then correct airflow direction is ensured, but implementation cost increases

Engineering Contradiction:
Improveairflow direction controlVSAvoidimplementation cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent employs a inexpensive pressure sensor instead of costly phase sequence switching components, frequency inverters, or soft starters. The pressure sensor is a simple, low-cost device that provides sufficient information about airflow direction without requiring expensive electrical control infrastructure. This dramatically reduces implementation cost while maintaining the ability to ensure correct airflow direction.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The invention substitutes expensive electrical control components with a simple mechanical pressure sensing system. Rather than using complex phase sequence management equipment, the system uses pressure variations in the airflow path to determine rotation direction, eliminating the need for costly electrical control hardware and reducing overall implementation cost.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If pressure sensor is used to detect airflow direction, then costly components are eliminated, but measurement precision requirements increase

Engineering Contradiction:
Improveimplementation costVSAvoidpressure measurement precision
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The pressure sensor provides continuous feedback about pressure changes in the flow path during motor startup and operation. The controller monitors these pressure variations over time, using the trend of pressure changes rather than absolute precision to determine airflow direction. This feedback mechanism allows the system to achieve reliable direction detection with moderate measurement precision by analyzing pressure trends rather than requiring high-precision absolute pressure measurements.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs pressure measurements during the motor startup phase before full operation begins. By measuring pressure changes during this preliminary period when the impeller is accelerating, the system can determine rotation direction before the motor reaches full speed. This timing allows sufficient pressure differentiation to occur while avoiding the need for high precision measurements under full-load conditions.

Inventive Principle:
Principle #10Preliminary action

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

Provides a reliable and cost-effective solution to manage motor rotation direction by dispensing with costly components, reducing the amount of dust-laden air blown out in the reverse direction.

Implementation Method 1

measuring a pressure in the flow path using a pressure sensor, determining a direction of the airflow based on the pressure

Methodology Applied
Scientific EffectPressure measurement:

Data Source

PatentEP3678786B1Separator and method of operating a separator
Publication Date: 2025.12.17 HUSQVARNA AB
  • EP3678786B1 patent drawingFigure 1

AI summary

The present document discloses a method of operating a separator (1) for separating particles from a particle-laden airflow, wherein the separator comprises a flow path (F), a separation unit (11, 12, 13), arranged in the flow path (F), an impeller (14), arranged in the flow path (F), and an electric motor (15), configured to drive the impeller (14) so as to generate the airflow in the flow path (F). The method comprises initiating a power supply to the electric motor (15), measuring a pressure in the flow path using a pressure sensor (16a, 16b, 16c, 16d), determining a direction of the airflow based on the pressure, and if the direction of the airflow does not correspond to a desired direction of the airflow, then changing a phase sequence of the power supply to the electric motor (15). The document further discloses a separator (1) and a system comprising a separator (1) and a floor grinding machine (2).