Overflow Sensor Assembly for Removable Drain Pan HVAC Systems

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Solution Overview

Problem

Conventional HVAC units with removable drain pans face issues with float switches that can get damaged or interfere with the removal of the drain pan, leading to potential overflow and damage due to clogged drain lines, as they are not designed to accommodate removable pans effectively.

Innovation Solution

An overflow sensor assembly with flexible sensor probes mounted on a bracket that extends into the condensate drain pan, using metal springs or wires to detect fluid levels before overflow, allowing for easy removal and maintenance of the drain pan without interfering with the sensor system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a float switch is used to detect condensate fluid level, then overflow detection capability is improved, but the float switch interferes with removable drain pan removal and may get damaged

Engineering Contradiction:

Improveoverflow detection capabilityVSAvoiddrain pan removal ease

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The float switch assembly is separated from the drain pan structure. The sensor mounting bracket is coupled to the HVAC unit housing rather than the drain pan, allowing the drain pan to be removed independently without affecting the float switch or its lead wires.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A sensor mounting bracket serves as an intermediary structure that holds the float switch assembly. This bracket is fixed to the HVAC unit while the drain pan remains removable, mediating between the need for stable sensor positioning and easy drain pan removal.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If a float switch is installed in the drain pan, then overflow detection is achieved, but the lead wires may get disconnected and the float switch may get damaged

Engineering Contradiction:

Improveoverflow detection reliabilityVSAvoidfloat switch durability

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The float switch and its lead wires are extracted from the drain pan environment. By mounting the float switch on a bracket fixed to the HVAC unit housing rather than inside the drain pan, the vulnerable lead wires are no longer subjected to damage risks during drain pan removal or engagement.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The sensor mounting bracket provides a stable, pre-positioned mounting structure that protects the float switch assembly from mechanical damage. The bracket's rigid coupling to the HVAC unit housing prevents the float switch from being struck or dislodged during drain pan operations.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Ease of repair

If the drain pan is configured to be removable for cleaning, then maintenance ease is improved, but the float switch interferes with smooth removal and insertion

Engineering Contradiction:

Improvedrain pan maintenance easeVSAvoiddrain pan insertion and removal smoothness

Core Design Contradiction:

Ease of repairVSEase of operation

Solution Approach 1:

The detection system is segmented into a fixed mounting bracket and a removable drain pan. This segmentation allows the drain pan to be independently removed for cleaning without any attachment to or interference from the float switch assembly.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of attaching the sensor to the removable drain pan, the patent inverts the approach by fixing the sensor to the HVAC unit housing. This reversal eliminates the interference problem while maintaining overflow detection functionality.

Inventive Principle:

Principle #13The other way round (Inversion)

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

Prevents overflow by detecting condensate fluid levels accurately and triggering a shutdown before overflow occurs, ensuring the drain pan can be easily removed and maintained without damaging the sensor system, thus preventing structural and property damage.

Implementation Method 1

The sensor probes are configured to activate an overflow detection circuit when the sensor probes come in contact with condensate fluid collected in the condensate drain pan

Methodology Applied

Scientific EffectElectrical contact detection: Conduction (electrical)

Implementation Method 2

Each sensor probe is defined by a sensor element and a spring that is coupled to the sensor element

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 3

a spring that is coupled to the sensor element

Methodology Applied

Scientific EffectSpring force: Spring

Data Source

PatentUS11906183B2Overflow sensor assembly in temperature control systems

Publication Date: 2024.02.20 RHEEM MFG CO

AI summary

Embodiments include overflow sensor assemblies for water heaters, HVAC systems, and other devices for which temperature control systems may be used. An example overflow sensor assembly for detecting fluid leaks at a device may include a sensor probe configured to be in electrical communication with a power supply, and a sensor mounting bracket that forms a ground, the sensor mounting bracket configured to attach to a mounting surface on the device and suspend the sensor probe in a condensate drain pan of the device. An overflow detection circuit can be activated when the sensor probe and the sensor mounting bracket come in contact with a condensate fluid.