Adaptive Actuator Safety Control for HVAC Flap Positioning

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Solution Overview

Problem

Existing safety controllers for HVAC and fire protection systems are inflexible in responding to power failures, often resulting in suboptimal positioning of flaps or valves, which can lead to increased damage during events like fires, as they cannot adapt to changing conditions such as smoke levels or temperature.

Innovation Solution

A safety controller with a control value output circuit that adapts the safety position based on variable status signals, using logic to determine the optimal position between 'open', 'closed', or 'half-open' based on detected conditions, and utilizing a capacitive energy store to maintain the actuator in the defined safety position during power failures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a fixed safety position is used in the event of power failure, then the system is simple to operate, but the system cannot adapt to changing conditions such as smoke levels or temperature

Engineering Contradiction:
Improveadaptability to changing conditionsVSAvoidcomplexity of safety control system
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies dynamics by transitioning from a fixed safety position to a dynamic safety position that changes based on real-time status signals. The control circuit continuously monitors status signals (smoke density, temperature, water flow) and adjusts the safety position accordingly, making the system adaptive rather than static. This resolves the contradiction by enabling adaptability through dynamic adjustment while keeping the control logic relatively simple.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of safety position from a fixed value to a variable value that depends on status signals. The control circuit evaluates multiple status signals and determines the safety position based on their combined state, allowing the system to adapt to different fire scenarios. This parameter change enables versatility without requiring complex additional hardware.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If flaps are fully closed during power failure, then fire spread is prevented, but smoke gases cannot be removed from the ventilation system

Engineering Contradiction:
Improvefire spread preventionVSAvoidsmoke gas accumulation
Core Design Contradiction:
Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by differentiating the safety position for different locations and conditions. Instead of a universal closed position, the control circuit determines specific safety positions based on local status signals such as smoke density detectors, temperature sensors, and water flow detectors. This allows different parts of the ventilation system to have different flap positions optimized for their specific conditions, preventing fire spread in some areas while allowing smoke evacuation in others.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses feedback from status signals to continuously adjust the safety position. The control circuit receives feedback from smoke density detectors, temperature sensors, and water flow detectors, and adjusts the flap position based on this feedback. This closed-loop control enables the system to respond to changing conditions in real-time, balancing fire prevention with smoke evacuation needs.

Inventive Principle:
Principle #23Feedback

3Object-generated harmful factors

If flaps are fully open for smoke evacuation, then smoke gases can be removed, but fire can spread along the ventilation system

Engineering Contradiction:
Improvesmoke gas removalVSAvoidfire spread risk
Core Design Contradiction:
Object-generated harmful factorsVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by determining different safety positions for different ventilation system components based on their local conditions. The control circuit evaluates status signals from each location (smoke density, temperature, water flow) and sets appropriate flap positions locally. This allows smoke evacuation in areas where it is safe while maintaining fire containment in areas where fire spread risk is high.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses feedback from multiple status signals to dynamically adjust flap positions. The control circuit continuously monitors smoke density detectors, temperature sensors, and water flow detectors, and adjusts the safety position based on this feedback. This enables the system to optimize the balance between smoke evacuation and fire prevention in real-time based on actual conditions.

Inventive Principle:
Principle #23Feedback

4Reliability

If multiple status signals are monitored to determine safety position, then the system responds optimally to different fire scenarios, but the control logic becomes more complex

Engineering Contradiction:
Improveaccuracy of safety responseVSAvoidcomplexity of control logic
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies partial action by evaluating status signals in a hierarchical manner. The control circuit first checks critical signals (such as direct flame detection or high-temperature alerts) that require immediate closure, and only evaluates less critical signals if those are not present. This approach achieves reliable safety responses for critical scenarios while keeping the control logic simpler for less severe situations.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent changes the control logic from a simple on/off decision to a multi-parameter evaluation that determines different safety positions. The control circuit evaluates multiple status signals and maps their combined state to appropriate safety positions (fully closed, partially closed, or fully open). This parameter-based approach improves reliability by considering multiple factors while maintaining structured and manageable control logic.

Inventive Principle:
Principle #35Parameter changes

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 solution allows for more flexible and adaptive response to changing conditions during power failures, minimizing damage by dynamically adjusting the position of flaps or valves to suit the current risk situation, such as fully closing during high temperatures or partially opening for smoke evacuation.

Implementation Method 1

The voltage or capacitance can be increased by placing multiple capacitors in series or in parallel

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP2491639B1Safety controller for an actuator
Publication Date: 2015.11.25 BELIMO HOLDING AG
  • EP2491639B1 patent drawingFigure 1~2
  • EP2491639B1 patent drawingFigure 3~4

AI summary

The invention relates to a safety controller for an actuating drive (2.1, 2.2, 2.3) for controlling a gas flow or a liquid flow in an open-loop or closed-loop manner by means of a flap (3.1, 3.2, 3.3) or a valve, in particular in the field of heating, ventilation, and air conditioning (HVAC) systems, fire-protection systems, and/or room protection systems. A safety circuit (9.1, 9.2, 9.3) is implemented to ensure the energy supply in a safety operating mode if an electricity supply circuit (8.1, 8.2, 8.3) drops off or is lost. A control value output circuit (1.1, 1.2, 1.3) detects status signals, in particular signals of a sensor (11.1, 11.2, 11.3), and/or status parameters of a system and/or a specifiable setting of an adjustment device that can be actuated manually. The safety control value is set to one of at least two different control values (SW1, SW2,...) depending on the status signals so that the safety position of the flap is determined adaptively.