Ventilation Fan Speed Control for Filter Clogging

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Solution Overview

Problem

Ventilating apparatuses with blower fans and filters face challenges in maintaining required ventilation levels and preventing fan overload due to filter clogging, which increases ventilation resistance and decreases airflow, making it difficult to balance ventilation needs with heat loss management.

Innovation Solution

The ventilating apparatus increases the target rotational speed of the blower fan at a prescribed frequency determined by the time input value of the filter sign, which considers the working environment, and includes a filter sign to alert when maintenance is needed, preventing overload and maintaining airflow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the rotational speed of the blower fan is constantly maintained at a target rotational speed, then the control is simple, but the amount of ventilation decreases when the filter becomes clogged

Engineering Contradiction:
Improvecontrol simplicityVSAvoidamount of ventilation
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The patent implements dynamic adjustment of the target rotational speed based on operation time. The control unit increases the target rotational speed at prescribed frequency intervals, transforming the static control approach into a dynamic one that adapts to filter clogging progression, thereby maintaining ventilation effectiveness without complex real-time sensing

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The control unit performs preliminary actions by proactively increasing the target rotational speed before the filter becomes severely clogged. This preventive approach anticipates the clogging issue and compensates in advance, maintaining ventilation flow without requiring complex real-time detection systems

Inventive Principle:
Principle #10Preliminary action

2Productivity

If the operation frequency of the blower fan is increased in response to filter clogging, then the amount of ventilation is maintained, but the risk of fan overload increases

Engineering Contradiction:
Improveamount of ventilationVSAvoidfan overload risk
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies periodic action by increasing the target rotational speed at predetermined frequency intervals rather than continuously or in response to real-time clogging detection. This periodic adjustment maintains ventilation effectiveness while avoiding excessive speed increases that could cause fan overload

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The control unit applies partial action by increasing the target rotational speed in controlled increments at specific intervals rather than maximizing the speed continuously. This partial adjustment is sufficient to counteract filter clogging effects while staying within safe operational limits to prevent fan overload

Inventive Principle:
Principle #16Partial or excessive action

3Productivity

If the target rotational speed is increased frequently, then the amount of ventilation is maintained, but the fan operation becomes overloaded

Engineering Contradiction:
Improveamount of ventilationVSAvoidfan operation load
Core Design Contradiction:
ProductivityVSPower

Solution Approach 1:

The patent uses periodic action with prescribed frequency intervals to increase the target rotational speed, balancing the need to maintain ventilation against the risk of excessive power consumption and fan overload. The periodic nature ensures adjustments are made only when necessary

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The control unit changes the rotational speed parameter in controlled increments at specific time intervals rather than making large frequent changes. This parameter adjustment strategy maintains ventilation effectiveness while managing power consumption and avoiding fan overload

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2172713B1Ventilation device and method of controlling the same
Publication Date: 2019.03.27 DAIKIN INDUSTRIES LTD
  • EP2172713B1 patent drawingFigure 1
  • EP2172713B1 patent drawingFigure 2
  • EP2172713B1 patent drawingFigure 3

AI summary

The present invention provides a ventilating apparatus that comprises blower fans and filters, wherein, even if the filters become clogged, it is possible to prevent the operation of the blower fans from overloading and to prevent, as much as possible, the amount of ventilation from decreasing. A ventilating apparatus (1) comprises blower fans (4, 5), filters (6, 7), which collect dust and the like contained in air flows generated by the blower fans (4, 5), and a control unit (8) that uses a time input value (ts), which is for outputting a filter sign to a reporting unit (9), to increase a target rotational speed (ns) of the blower fans (4, 5) with a prescribed frequency.