Safety Drive Circuit for Springless Flap and Valve Return
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Solution Overview
Problem
Conventional safety circuits for returning flaps or valves to a safety position in HVAC and fire protection systems face issues with wear and instability, particularly during power failures, due to the use of return springs and existing capacitor-based solutions which generate heat and have complex voltage regulation.
Innovation Solution
A safety drive with a capacitive energy store and a DC-DC converter that can operate in both step-down and step-up modes, using FET switches and a monitoring unit to control energy flow, eliminating the need for separate charging and motor operation circuits and reducing wear by using a supercapacitor for energy storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a return spring is used to return the flap or valve to safety position during power failure, then the return function is achieved, but wear on the mechanism increases and the spring loses tension over time
Solution Approach 1:
The patent replaces the mechanical return spring system with an electrical energy storage system (capacitor) and control circuit. The capacitor stores electrical energy during normal operation and releases it during power failure to drive the motor back to safety position, eliminating mechanical wear and tension loss issues inherent in spring systems.
Solution Approach 2:
The patent implements periodic charging of the capacitor during normal operation and periodic discharging during emergency situations. The control circuit continuously monitors power supply status and automatically switches between charging mode (normal operation) and discharging mode (power failure), creating a periodic action pattern that ensures reliable return function.
2Duration of action of moving object
If a capacitor-based safety circuit is used to replace return spring, then wear is reduced, but the charging circuit produces significant heat and requires complex voltage regulation
Solution Approach 1:
The patent combines the charging circuit and motor operation circuit into a single integrated power supply system. The same power supply unit charges the capacitor during normal operation and the same motor uses this stored energy during power failure, eliminating the need for separate high-power charging circuits that generate excessive heat.
Solution Approach 2:
The patent changes the operating parameters of the capacitor-based system by using a motor with high moment of inertia and implementing soft-start control. This allows the capacitor to discharge at lower current levels over a longer period, reducing I²R losses and heat generation while still achieving the required return function.
3Stability of the object's composition
If multiple power supply units and voltage regulators are used to achieve constant voltage during emergency operation, then voltage stability is improved, but device complexity increases
Solution Approach 1:
The patent designs a universal power supply unit that performs multiple functions: it operates as the main motor driver during normal operation, charges the capacitor during normal operation, and provides emergency power during power failure. This multi-functional design eliminates the need for separate power supply units and voltage regulators for different operating modes.
Solution Approach 2:
The patent implements dynamic voltage regulation through the control circuit that adjusts its operation based on real-time power supply status. The same circuit dynamically switches between voltage regulation modes (charging mode, motor operation mode, emergency mode) without requiring multiple static voltage regulation systems, thereby reducing complexity while maintaining voltage stability.
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 simplifies the control circuit and energy flow, reduces wear, and provides stable voltage regulation during power failures, allowing efficient and reliable return of flaps or valves to a safety position without the need for return springs, while minimizing heat generation and complexity.
Implementation Method 1
a capacitive energy store (20), in particular a double-layer capacitor or supercapacitor
Implementation Method 2
a DC-DC converter (22) with an energy flow (44) in two directions, wherein the DC-DC converter (22) has a step-down switching mode that lowers the output voltage compared to the input voltage and a step-up switching mode that increases the output voltage compared to the input voltage
Implementation Method 3
using FET switches and a monitoring unit to control energy flow
Data Source
Figure 1
Figure 1a
Figure 2~3
AI summary
A safety drive unit (10) with a safety circuit (12) resets a flap or a valve into a specified safety position for controlling a gas or liquid volumetric flow, in particular in the field of heating, ventilation, and air conditioning (HVAC) fire protection and monitoring systems. The safety drive unit (10) essentially comprises an actuator (14) with a controllable electric motor (28), a capacitive energy storage unit (20), an energy converter (22) with a power module, and a power supply (18). During normal operation, the electric current in the power module of the energy converter (22) is converted to a lower voltage and stored in the capacitive energy storage unit (20) with at least one double-layer capacitor. If the voltage drops below a predetermined value or if there is a power failure, the stored electrical charge is converted back to a higher voltage by the same power module, and the electric motor (28) is activated until the specified safety position is reached.