Vaporizer Flow-Rate Calculation to Prevent Pump Idling and Overheating

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Solution Overview

Problem

Evaporators in household appliances often experience pump idling due to flow rate fluctuations, leading to reduced service life and increased noise emissions during time-controlled emptying.

Innovation Solution

A method that involves filling the evaporator to a predetermined level, initiating a time measurement when the level falls below this threshold, and calculating the delivery rate by dividing the liquid volume by the emptying time period, which includes correcting for offsets to prevent overheating and account for system tolerances, thereby preventing pump idling without additional sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If time-controlled emptying is used, then the evaporator can be emptied at regular intervals, but the pump may idle due to flow rate fluctuations, reducing service life and increasing noise

Engineering Contradiction:
Improveemptying efficiencyVSAvoidpump service life
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies feedback by continuously monitoring the actual liquid level during emptying and comparing it with the predicted level based on time. When the actual level deviates from the predicted level (indicating pump idling), the system adjusts the pump operation to maintain optimal flow, preventing excessive idling and extending pump service life while maintaining emptying efficiency

Inventive Principle:
Principle #23Feedback

2Productivity

If time-controlled emptying is used, then the evaporator can be emptied at regular intervals, but noise emissions increase due to pump idling

Engineering Contradiction:
Improveemptying efficiencyVSAvoidnoise emissions
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The feedback mechanism detects pump idling through liquid level deviation and adjusts pump operation accordingly, reducing unnecessary pump running time and thereby decreasing noise emissions while maintaining effective emptying performance

Inventive Principle:
Principle #23Feedback

3Reliability

If additional sensors are added to prevent pump idling, then pump service life can be extended, but device complexity and cost increase

Engineering Contradiction:
Improvepump service lifeVSAvoidsensor system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system uses its existing level sensor to perform dual functions: both monitoring the liquid level for emptying control and detecting pump idling conditions through deviation from predicted level. This self-service approach eliminates the need for additional sensors while extending pump service life through intelligent control

Inventive Principle:
Principle #25Self-service

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 extends the service life of the emptying device, reduces noise, and allows for cost-effective operation with higher tolerances, ensuring efficient and reliable emptying of the evaporator.

Implementation Method 1

the evaporator having at least part of a level detector for detecting a predetermined level and at least part of an overheating detector for detecting overheating of the heater

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 2

at least part of a level detector for detecting a predetermined level

Methodology Applied
Scientific EffectLevel detection:

Implementation Method 3

at least part of an overheating detector for detecting overheating of the heater

Methodology Applied
Scientific EffectTemperature detection:

Data Source

PatentEP3125695B1Operation of a vaporizer of a domestic appliance
Publication Date: 2020.02.26 BSH HAUSGERATE GMBH
  • EP3125695B1 patent drawingFigure 1
  • EP3125695B1 patent drawingFigure 2
  • EP3125695B1 patent drawingFigure 3

AI summary

The invention relates to a method (S1-S9) which is used to operate a vaporizer (1) of a domestic appliance (H), which vaporizer is provided with a heater (9), wherein the vaporizer (1) has at least part of a fill-level detector (16) for detecting a predetermined fill level (L1) and at least part of an overheating detector (9) for detecting overheating of the heater (9), wherein the method comprises at least the following steps: (S1) filling the vaporizer (1) at least up to the predetermined fill level (L1); (S2) draining the vaporizer (1) by means of a draining device (22); (S3) starting a time measurement (Z0) when the fill level drops below the predetermined fill level (L1), (S4) switching on the heater (9) of the vaporizer (1) when the fill level falls below the predetermined fill level (L1); (S5) stopping the time measurement (Z0) when overheating of the heater (9) is detected; (S6) calculating a flow rate during the draining of the vaporizer (1) from a duration for draining determined by means of the time measurement (Z0). A steam treatment device (H) is designed to perform the method.