Multi-Sensor Fire Suppression Control for Cooking Hood Systems
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Solution Overview
Problem
Existing fire suppression systems in cooking hoods fail to differentiate between flare-ups from regular cooking and actual fires, leading to unnecessary activation or failure to suppress fires due to reliance on fixed temperature measurements without considering exhaust temperature changes or cooking appliance states.
Innovation Solution
A network-based or rule-based system that combines multiple sensor inputs, including temperature and airflow measurements, to determine the cooking appliance state and control exhaust flow rates, activating fire suppression mechanisms only when a fire is confirmed, using sensors to differentiate between cooking states and fire conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fixed absolute temperature measurement is used to detect fire conditions, then the fire suppression system can be activated when a temperature threshold is reached, but it cannot differentiate between flare-ups from regular cooking and actual fires, leading to unnecessary activation or failure to suppress fires
Solution Approach 1:
The patent combines multiple sensor types (temperature sensors, airflow sensors, and optionally optical sensors) to create a multi-parameter detection system. The controller integrates signals from these sensors to distinguish between flare-ups and actual fires by analyzing both temperature patterns and corresponding airflow conditions, thereby improving fire detection reliability while maintaining measurement precision.
Solution Approach 2:
The system continuously monitors temperature and airflow parameters and uses feedback from these measurements to adjust its fire detection logic. By analyzing the relationship between temperature rise and airflow changes over time, the system can differentiate between normal cooking flare-ups (which have specific airflow-temperature patterns) and actual fires, improving detection reliability without sacrificing measurement precision.
2Speed
If fire suppression is activated based on fixed temperature thresholds, then the system responds quickly to temperature changes, but it activates unnecessarily during regular cooking flare-ups or fails to activate during actual fires
Solution Approach 1:
The patent merges temperature-based detection with airflow-based detection to create a more accurate fire identification system. The controller analyzes both parameters simultaneously, allowing quick response to genuine fires while filtering out false alarms from normal cooking operations. This combination maintains the speed advantage of temperature-based systems while improving suppression accuracy through additional verification parameters.
Solution Approach 2:
The system dynamically adjusts its detection thresholds and response criteria based on the relationship between temperature and airflow measurements. Rather than using fixed temperature thresholds, the system evaluates the dynamic interplay between multiple parameters to determine whether activation conditions are met, enabling both rapid response to actual fires and suppression of unnecessary activations during normal cooking.
3Reliability
If multiple sensor inputs and complex differentiation logic are used to accurately distinguish cooking states from fire conditions, then fire detection reliability improves, but the device complexity increases
Solution Approach 1:
The controller serves multiple functions: it monitors temperature, analyzes airflow patterns, differentiates between cooking states and fire conditions, controls exhaust flow rates, and activates fire suppression when necessary. By consolidating these diverse functions into a single multi-functional control unit, the system achieves high fire detection reliability without proportionally increasing overall device complexity.
Solution Approach 2:
The patent segments the detection and control functions into distinct modular components (temperature sensing module, airflow sensing module, control logic module, exhaust control module, fire suppression module). This segmentation allows each component to be optimized independently while maintaining overall system reliability, and facilitates easier installation, maintenance, and troubleshooting.
4Loss of energy
If exhaust flow rate is controlled based on cooking appliance state to ensure minimal excess air exhaust, then energy efficiency improves, but the system must accurately differentiate between various cooking states and fire conditions
Solution Approach 1:
The system combines temperature and airflow measurements to create a more robust basis for determining cooking appliance states. By analyzing the relationship between these two parameters, the controller can more accurately distinguish between different cooking states (such as normal cooking, flare-ups, and fires), thereby enabling precise exhaust flow control that minimizes energy loss without misclassifying cooking states.
Solution Approach 2:
The system uses changes in multiple parameters (temperature, airflow rate, and their relationships over time) to detect and differentiate cooking states. Rather than relying on a single parameter threshold, the system analyzes patterns of parameter changes, making it easier to distinguish between various cooking conditions and enabling more accurate exhaust flow control to reduce energy loss.
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
Effectively differentiates between cooking states and fire conditions, ensuring minimal excess air exhaust, efficient fire suppression, and accurate activation of fire suppression systems, thereby preventing unnecessary interventions and ensuring effective fire containment.
Implementation Method 1
measuring the exhaust air temperature in the vicinity of the exhaust hood
Implementation Method 2
measuring a radiant temperature of the exhaust air in the vicinity of the cooking appliance
Implementation Method 3
determining a total heat gain from the cooking appliance
Implementation Method 4
The detection of the instantaneous heat may be based on airflow measurements
Data Source
AI summary
A method of responding to a condition in an exhaust ventilation system that has an exhaust hood includes receiving, at a control module, an exhaust air temperature signal representing a temperature of the exhaust air in a vicinity of the exhaust hood, the exhaust air temperature signal being generated by a temperature sensor. The method also includes receiving a radiant temperature signal representing a temperature of a surface of a cooking appliance that generates the exhaust air, the radiant temperature signal being generated by a radiant temperature sensor. Further, the method includes receiving a pressure signal representing the pressure in the hood and determining a state of the cooking appliance based on the received exhaust air temperature signal, the received radiant temperature signal, and the received pressure signal. Finally, the method responds to the determined appliance state by outputting a control signal from the control module.