Steam Generator Water Level Control Using a Temperature Sensor

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Solution Overview

Problem

Existing fabric treatment appliances, such as washing machines, rely on pressure and electrical conduction sensors to control water supply to steam generators, which may not be economical, reliable, or elegant for maintaining a desired water level.

Innovation Solution

A fabric treatment appliance equipped with a temperature sensor to control water flow through a supply conduit based on the temperature of the steam generator chamber, ensuring a predetermined water level is maintained, using a controller and valve system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If pressure sensors and electrical conduction sensors are used to control water supply, then water level control is achieved, but device complexity and cost increase

Engineering Contradiction:

Improvewater level control reliabilityVSAvoidsensor system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces mechanical/electrical sensors (pressure sensors, electrical conduction sensors) with a temperature-based detection system. The temperature sensor detects temperature changes in the steam generator chamber that correspond to water level changes, substituting complex mechanical sensing with thermal sensing that is already inherent in the steam generation process.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The steam generator's heating process naturally creates temperature variations that indicate water level status. Instead of requiring separate detection systems, the system uses the thermal field already present during operation to self-indicate water level conditions, eliminating the need for additional specialized sensors.

Inventive Principle:

Principle #25Self-service

2Reliability

If pressure sensors and electrical conduction sensors are used to control water supply, then water level control is achieved, but manufacturing cost increases

Engineering Contradiction:

Improvewater level control reliabilityVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Temperature sensors are generally less expensive and more durable than specialized pressure or electrical conduction sensors. The patent leverages this by using a standard temperature sensor that can withstand the steam generator environment, reducing both component cost and manufacturing complexity.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The temperature sensor serves dual purposes: monitoring the steam generation temperature for process control and simultaneously detecting water level conditions through temperature variations. This multi-functionality eliminates the need for separate water level sensing systems, reducing overall system cost.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Device complexity

If temperature sensor is used to sense water level, then device complexity is reduced, but measurement precision may be affected

Engineering Contradiction:

Improvecontrol system complexityVSAvoidwater level measurement precision

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The controller continuously monitors temperature sensor output and uses feedback control to determine water level status. By analyzing temperature variations over time and comparing them against predetermined thresholds, the system achieves precise water level detection despite using a general-purpose temperature sensor.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent exploits the relationship between temperature and water level by detecting temperature changes that occur as water level varies. Different water levels produce distinct temperature patterns in the steam generator chamber, allowing the system to translate temperature parameter changes into accurate water level information.

Inventive Principle:

Principle #35Parameter changes

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 method provides a more reliable and efficient control of water supply to the steam generator, preventing damage and ensuring consistent steam generation, thereby enhancing the operational stability and effectiveness of fabric treatment processes.

Implementation Method 1

a temperature sensor configured to sense a temperature representative of the steam generator chamber at a predetermined water level in the steam generator chamber

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS7681418B2Water supply control for a steam generator of a fabric treatment appliance using a temperature sensor

Publication Date: 2010.03.23 WHIRLPOOL CORP

AI summary

A fabric treatment appliance comprises a steam generator having a chamber configured to hold water; a supply conduit configured to transport water to the steam generator chamber; a temperature sensor configured to sense a temperature representative of the steam generator chamber at a predetermined water level in the steam generator chamber; and a controller coupled to the temperature sensor and configured to control flow of water through the supply conduit based on the sensed temperature to control the level of water in the steam generator chamber. The disclosure provides methods of water supply control that can employ the temperature sensor.