Capacitive Liquid Level Detection in Electronic Cigarettes

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Solution Overview

Problem

Existing electronic cigarettes lack an effective method to determine when the tobacco liquid in the liquid storage chamber is depleted or insufficient, leading to overheating of the heating element and potential health hazards due to formaldehyde generation.

Innovation Solution

Incorporating a capacitive transducer with metallic electrodes inside the liquid storage chamber to detect the tobacco liquid level, which emits an alert or cuts off power when preset values are reached, preventing overheating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If temperature monitoring is used to detect tobacco liquid depletion, then the detection method is simple to implement, but the detection accuracy is insufficient due to uneven heating element temperature

Engineering Contradiction:

Improvetobacco liquid level detection accuracyVSAvoiddetection system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the temperature-based detection method with a capacitive detection method. The capacitive transducer uses electrical field interaction with the tobacco liquid to determine liquid level, eliminating the need for temperature monitoring and providing more accurate detection regardless of heating element temperature distribution.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a capacitive transducer as an intermediary detection device between the user and the tobacco liquid level. This transducer acts as a mediator that directly measures liquid level through capacitance changes, providing accurate information without being affected by the heating element's thermal state.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If no liquid level detection is implemented, then the device structure remains simple, but the heating element is damaged due to overburning when tobacco liquid runs out

Engineering Contradiction:

Improveheating element protectionVSAvoiddetection and control system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a feedback control system where the capacitive transducer continuously monitors tobacco liquid level and provides real-time information to the control unit. When the liquid level drops below a threshold, the control unit receives feedback and automatically cuts off power to the heating element, preventing overburning damage.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent performs preliminary detection of tobacco liquid level before damage can occur. The capacitive transducer proactively monitors the liquid level and triggers protective action in advance, preventing the heating element from entering a damaging overburn state rather than reacting after damage has begun.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 3:

The patent applies preliminary anti-action by implementing a protective mechanism that preemptively prevents overburning. The capacitive detection system and control unit work together to counteract the potential harmful effect of liquid depletion before it can damage the heating element, ensuring reliable operation.

Inventive Principle:

Principle #9Preliminary anti-action

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

Accurately determines the tobacco liquid level, preventing overheating of the heating element and ensuring user safety by alerting the user or cutting off power when the liquid is low.

Implementation Method 1

a capacitive transducer, electrically connected with the controlling unit, two electrodes of the capacitive transducer being disposed inside the liquid storage chamber for determining an amount of the tobacco liquid in the liquid storage chamber

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

the heating element is capable of heating the tobacco liquid to generate an aerosol that flows out from an aerosol passage later

Methodology Applied

Scientific EffectHeating: Heating

Data Source

PatentUS10912338B2Electronic cigarette and using method to accurately determine an amount of a tobacco liquid in a liuid storage chamber

Publication Date: 2021.02.09 SHENZHEN FIRST UNION TECH CO LTD

AI summary

An electronic cigarette includes: an atomizer, defining a liquid storage chamber formed therein; a heating element, communicated with the liquid storage chamber; a power supply, configured for supplying power; a controlling unit, one end of the controlling unit electrically connected with the power supply, the other end thereof electrically connected with the heating element; and a capacitive transducer electrically connected with the controlling unit. Two electrodes are disposed inside the liquid storage chamber for determining an amount of the tobacco liquid in the liquid storage chamber. A using method includes: conducting the electricity and controlling the heating element to atomize the tobacco liquid in the liquid storage chamber; detecting an amount of the tobacco liquid in the liquid storage chamber via the capacitive transducer. When the detected amount of the tobacco liquid reaches a preset value, the electronic cigarette emits alert information or cuts off the electricity.