Motorised Sliding Fire Door With Brushless Stepper Control
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Solution Overview
Problem
Existing sliding fire doors face challenges in ensuring safe and reliable automatic closure during a fire, with traditional systems like thermal fuses having long release times and electromagnetic devices causing slow and potentially dangerous panel movements, while standard motors are incompatible with the weight and construction requirements of fire doors.
Innovation Solution
A motorized sliding fire door system with a DC brushless stepper motor, hydromechanical assembly, and electronic control unit to control panel speed, ensuring safe and controlled movement, compatible with the weight and construction of fire doors, and preventing obstruction by obstacles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a counterweight system is used to ensure automatic closure, then the door closes automatically in case of fire, but the panel undergoes dangerous accelerations and speeds during closing
Solution Approach 1:
The patent replaces the traditional mechanical counterweight system with an electric motor (specifically a DC brushless stepper motor) to drive the panel closing. This substitution allows for controlled, gradual closing motion without the dangerous accelerations inherent in counterweight systems, while still ensuring automatic closure functionality through electronic control units that activate the motor in response to fire detection.
Solution Approach 2:
The patent introduces an electronic control unit as an intermediary between the fire detection system and the motor. This intermediary controls the motor's operation, ensuring that the panel closes at a safe, controlled speed while still achieving automatic closure. The control unit mediates between the need for automatic closure and the need to prevent dangerous panel movements.
2Ease of operation
If an electromagnetic device is used to restrain the panel, then the panel can be kept open during normal operation, but the closing speed is slow and potentially dangerous
Solution Approach 1:
The patent replaces the electromagnetic restraining device with an electric motor system for the closing action. While the electromagnetic device is eliminated, the motor provides controlled motion that is neither too fast nor too slow, achieving safe closing speeds through electronic control rather than relying on electromagnetic force characteristics.
3Device complexity
If a thermal fuse is used for fire detection, then the system is simple, but the release time is too long to meet current regulations
Solution Approach 1:
The patent replaces the thermal fuse with an electronic fire detection system that connects to the electronic control unit. This substitution dramatically reduces the response time compared to thermal fuses, allowing the door to close automatically within regulatory time limits while maintaining system reliability through electronic sensing and control.
4Device complexity
If a standard motor is used, then the system is simple, but the motor is incompatible with the weight and construction requirements of fire doors
Solution Approach 1:
The patent specifies a DC brushless stepper motor with particular parameters (voltage, current, torque, speed) that are appropriate for fire door applications. The motor's electrical and mechanical parameters are selected to match the weight and construction requirements of fire doors, ensuring reliable operation while maintaining controlled, safe closing speeds through electronic control.
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
Ensures safe, reliable, and controlled closure of fire doors, avoiding dangerous impacts and maintaining functionality even in the presence of obstacles, while complying with safety regulations.
Implementation Method 1
DC brushless stepper motor (34) capable of exerting a driving torque
Implementation Method 2
hydromechanical assembly (30) which is operationally connected to the first motion transmission means (26) for limiting the forward speed of each sliding panel (12)
Data Source
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AI summary
A sliding fire door is described, comprising: at least one sliding panel for closing a passageway; an upper linear guide, fixed to a wall at the passageway and oriented along a horizontal direction; sliding means integral with the panel and slidingly engaged with the upper linear guide to allow the panel to move between open positions and close positions of the passageway; at least one counterweight which is constrained to the panel by means of a rope and pulley drive system; and at least one speed limiting device for limiting the forward speed of the panel when it moves towards the close position of the passageway. The sliding fire door further comprises: at least one electronic control unit; at least one electric motor, configured to move the panel towards the open position of the passageway; at least one manual control means to activate and/or deactivate the electric motor; at least one smoke and/or heat sensor, designed to deactivate the electric motor; and at least one sensor for sensing the full opening of said passageway, designed to deactivate the electric motor.