Magnetic Float Switch Latching for Low-Level HVAC Shutoff
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Solution Overview
Problem
Existing fluid sensing devices for HVAC systems fail to reliably shut off electrical power at low liquid accumulation depths and require frequent manual resets, leading to intermittent tripping and short cycling, which can damage the system and its surroundings.
Innovation Solution
A latching magnetic float switch with a pivoting curved/bowed clamp arm and a hand-manipulated fastener/nut combination for easy installation, featuring a strong magnetic attraction mechanism that snaps into a TRIPPED state at low liquid levels, allowing for quick shut-off and manual reset, and includes elevation adjustment capabilities to maintain stability and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing fluid sensing devices are used, then they can detect liquid accumulation, but they fail to reliably shut off electrical power at low liquid accumulation depths and require frequent manual resets
Solution Approach 1:
The patent implements a latching mechanism that automatically locks the switch in the TRIPPED state after activation, eliminating the need for frequent manual resets. The strong magnetic attraction between the float magnet and toggle bar magnet creates a self-latching action that maintains the shut-off state until manual reset is intentionally performed, thereby reducing time loss from frequent resetting operations.
Solution Approach 2:
The patent replaces weak magnetic attraction mechanisms with a strong magnetic attraction system using specifically configured magnets (float magnet and toggle bar magnet). This substitution ensures reliable activation at low liquid depths and maintains stable latching without mechanical wear or drift, improving overall reliability of the shut-off function.
2Reliability
If existing fluid sensing devices are used, then they can operate in HVAC systems, but they cause intermittent tripping and short cycling that can damage the system
Solution Approach 1:
The latching mechanism ensures that once the switch trips due to liquid accumulation detection, it remains in the TRIPPED state until manually reset. This preliminary latching action prevents intermittent tripping and short cycling by maintaining a stable shut-off state, thereby eliminating harmful short cycling effects on the HVAC system.
Solution Approach 2:
The strong magnetic attraction system provides stable and consistent actuation without the mechanical instability that causes intermittent tripping. The magnetic field strength and configuration ensure reliable activation at the intended threshold and prevent false triggering, thereby protecting the HVAC system from damage due to unstable operation.
3Reliability
If a latching magnetic float switch with strong magnetic attraction is implemented, then reliable snap-locking action is achieved, but the device complexity increases
Solution Approach 1:
The patent uses a magnetic field-based latching mechanism instead of complex mechanical linkages or springs to achieve reliable snap-locking action. The strong magnetic attraction between the float magnet and toggle bar magnet provides inherent stability and reliability without requiring additional mechanical components, thereby limiting the increase in device complexity.
Solution Approach 2:
The patent optimizes the magnetic field strength and configuration parameters to achieve reliable snap-locking action. By carefully selecting magnet sizes, materials, and positioning, the patent ensures stable latching while avoiding unnecessary complexity in the magnetic mechanism design.
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
The solution provides reliable and reproducible snap-locking action, reducing switch malfunction and allowing for easy testing and reset without removal, ensuring stable operation even at low liquid accumulation depths, thus preventing system damage.
Implementation Method 1
the magnetic force between the two magnets is calculated to overcome all upward biasing influence on the toggle bar magnet, and the float magnet becomes a switch actuator for the toggle bar magnet causing it to shut-off fluid production when the toggle bar magnet undergoes fast downward movement toward the float magnet that results in a reliable and strong snap-locked latching magnetic engagement of the two magnets together
Data Source
AI summary
A latching magnetic float switch with a single fastener mounting clamp and pivoting toggle bar magnet interrupting an electrical circuit to stop fluid production once actuated by an initially offset float magnet first rotating a small distance in response to liquid accumulation in the collection pan upon which the switch is mounted, the float magnet then achieving a strong snap-locked latching magnetic engagement with the toggle bar magnet solely through building magnetic attraction between them, engagement continuing until the float magnet is manually reset into its original offset positioning. The 2-part clamp with a rotating curved/bowed clamp arm can mount the switch securely to both metal and plastic liquid collection pans with differing draft angles, and also provides a clamp base configured for elevation adjustment of the float housing relative to pans having different wall height dimensions and fluid production shut off when detected fluid depth is less than 0.5 inches.