Inductive Drain Sensor Cage for Frozen Display Case Clogs

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Refrigerated display cases face issues with drain line blockages due to food spills, algae, and bacterial growth, leading to water accumulation and potential overflow, which can cause safety hazards and damage to the refrigeration system, and traditional level sensing devices fail in frozen conditions.

Innovation Solution

A drain sensor system using an inductive frequency characterization method, where a support member with a cage configuration protects the sensor from debris, and the sensor measures changes in inductance to detect fluid or substance levels, generating an alarm if the level exceeds a prescribed threshold, and can operate in both medium and low-temperature environments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional level sensing devices are used to detect water accumulation in the display case tub, then the device structure is simple, but the sensing device fails to operate accurately in frozen conditions and cannot detect ice formation

Engineering Contradiction:
Improvesensing device operation reliabilityVSAvoidtemperature environment adaptability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent replaces traditional mechanical level sensing devices with an inductive sensor that uses electromagnetic fields to detect fluid levels. This substitution allows the sensor to operate reliably in frozen conditions where mechanical devices fail, as the inductive sensing mechanism is not affected by ice formation and can detect both liquid water and ice through changes in inductance based on the dielectric properties of the substances.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If the sensor is exposed directly to the drain area to detect substances, then the detection accuracy is high, but the sensor is subject to mechanical wear and corrosion from debris and substances

Engineering Contradiction:
Improvesubstance detection accuracyVSAvoidsensor durability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent introduces a protective cage structure as an intermediary between the sensor and the harsh drain environment. The cage allows electromagnetic fields to penetrate for accurate detection of substances and fluid levels while physically protecting the sensor from mechanical wear, corrosion, and direct contact with debris. This intermediary structure resolves the contradiction by enabling both high detection accuracy and sensor durability.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If a protective structure is added around the sensor to prevent contact with debris, then the sensor durability is improved, but the device complexity increases

Engineering Contradiction:
Improvesensor protection from debrisVSAvoidsensor assembly structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs a simple cage-like protective structure that provides adequate protection while maintaining design simplicity. The cage acts as a flexible protective shell that allows electromagnetic field penetration for sensing while preventing direct contact between debris and the sensor. This approach improves sensor durability without significantly increasing device complexity, as the cage structure is straightforward to implement and integrate.

Inventive Principle:
Principle #30Flexible shells and thin films

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 detects clogged drains and prevents water overflow by accurately measuring fluid levels, including ice, and provides early warning systems to prevent damage and safety hazards, while being resistant to mechanical wear and corrosion.

Implementation Method 1

A drain sensor system using an inductive frequency characterization method, where a support member with a cage configuration protects the sensor from debris, and the sensor measures changes in inductance to detect fluid or substance levels

Methodology Applied
Scientific EffectInductance: Inductor

Data Source

PatentEP3101396B1Refrigerated display case with a sensor to detect a clogged drain
Publication Date: 2018.08.15 PARKER HANNIFIN CORP
  • EP3101396B1 patent drawingFigure 1
  • EP3101396B1 patent drawingFigure 2
  • EP3101396B1 patent drawingFigure 3A~3B

AI summary

A drain sensor (30) includes a support member (80) for placement relative to a drain (32), the support member including a cage. A sensor is attached to the support member and arranged within the cage, the sensor operative to provide an inductance measurement proportional to a level of fluid, moisture or a solid substance relative to the sensing element. Preferably the sensing element comprises an inductor forming an impedance transformer of the surrounding fluid, moisture or solid substance, and the measurement circuitry is configured to supply an oscillating current to the inductor and to calculate an inductance of the of the impedance transformer based on a resonant frequency of the impedance transformer. The level of liquid is determined from the inductance measurement. The sensor (30) may be used in a refrigerated display case (10) having a drain (32), to detect fluid level at the drain.