Dryer Humidity Sensor Positioning for Accurate Dryness Detection
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Solution Overview
Problem
Conventional dryers face challenges in accurately determining the dryness of materials due to positional limitations of electrode sensors and issues with humidity sensors, such as foreign material accumulation, leading to incomplete drying or overdrying.
Innovation Solution
A dryer design incorporating a humidity sensor positioned in a flow path with a velocity of at least 10 m/s between the drum and heat exchanger, where air flows straightly, allowing for accurate humidity detection without physical contact and minimizing foreign material accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an electrode sensor is used to measure dryness degree through physical contact with the material, then the measurement can be performed, but the sensor position is limited and cannot accurately measure all materials in the drum
Solution Approach 1:
The patent replaces the mechanical contact-based electrode sensor with a non-contact humidity sensor that detects moisture levels through electromagnetic radiation. This substitution eliminates the need for physical contact between the sensor and material, allowing the sensor to be positioned in the air flow path rather than requiring direct contact with rotating clothes, thereby resolving the positioning limitation while maintaining measurement capability.
2Measurement precision
If a humidity sensor is used to detect moisture without physical contact, then accurate dryness determination is possible, but foreign materials accumulate in the sensor hole during drying
Solution Approach 1:
The patent introduces a pre-filter positioned upstream in the air flow path that captures foreign materials (lint, dust) before they reach the humidity sensor. This preliminary action of filtering the air stream prevents contamination of the sensor while allowing moisture detection to proceed accurately, thus resolving the contradiction between non-contact measurement and foreign material accumulation.
3Reliability
If additional drying time is applied unconditionally to ensure complete drying, then all materials are dried, but overdrying occurs and drying time increases
Solution Approach 1:
The patent implements a feedback control system where the humidity sensor continuously monitors moisture levels in the air flow, and the controller adjusts the drying process in real-time based on this feedback. When the sensor detects that moisture levels have reached the target threshold, the system automatically terminates the drying cycle, eliminating the need for unconditional additional drying time and preventing overdrying while ensuring complete drying of all materials.
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 solution enables precise determination of the dried state of materials, overcoming the limitations of electrode sensors and addressing the issues with humidity sensors, ensuring complete drying without overdrying.
Implementation Method 1
a heat exchanger configured to remove moisture from air flowing and heat and discharge the moisture-removed air
Implementation Method 2
a fan configured to generate a flow of the air flowing along a flow path formed so that the air discharged from the heat exchanger flows to the heat exchanger via the drum and the humidity sensor
Implementation Method 3
a humidity sensor configured to detect a humidity of the air flowing from the drum
Data Source
AI summary
A dryer is disclosed. The dryer includes a heat exchanger configured to remove moisture from air flowing and heat and discharge the moisture-removed air, a drum containing a material to be dried, a humidity sensor configured to detect a humidity of the air flowing from the drum, a fan configured to generate a flow of the air flowing along a flow path formed so that the air discharged from the heat exchanger flows to the heat exchanger via the drum and the humidity sensor, and a processor configured to determine a dried state of the material to be dried based on the humidity detected through the humidity sensor, and the humidity sensor is disposed at a position where a flow velocity of the air is equal to or higher than a predetermined velocity in the flow path formed between the drum and the heat exchanger.