Liquid level detection device and refrigeration cycle apparatus
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Solution Overview
Problem
Conventional liquid level detection sensors in refrigeration cycle apparatuses face issues with false detection due to the presence of liquid droplets in the gaseous part, leading to erroneous determination of liquid levels, particularly in systems using heating, capacitance, ultrasonic, and optical sensors.
Innovation Solution
A liquid level detection device with a configuration where the first plate is disposed orthogonal to the flow direction of fluid, acting as a shielding portion to prevent liquid droplets from contacting the heat generating element or sensor components, thereby reducing false detection and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional liquid level detection sensors (heating, capacitance, ultrasonic, or optical types) are used in a refrigeration cycle apparatus, then the liquid level can be detected, but false detection occurs when liquid droplets are present in the gaseous part, leading to erroneous determination of liquid levels
Solution Approach 1:
The patent introduces a shielding plate as an intermediary component positioned between the liquid droplets and the detection sensor. This shielding plate selectively blocks liquid droplets from reaching the sensor while allowing the detection of actual liquid levels, thereby eliminating false detections caused by suspended droplets and improving both measurement precision and reliability
2Ease of operation
If the detection sensor is exposed to the fluid flow to detect liquid levels, then detection function is maintained, but liquid droplets in the gaseous part contact the sensor causing false detection
Solution Approach 1:
The shielding plate serves as a protective intermediary that filters out harmful liquid droplets from the fluid flow before they can contact the detection sensor. This allows the sensor to remain exposed to the fluid for detection purposes while being protected from false detection causes, maintaining detection functionality while eliminating harmful interference
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
The solution effectively reduces erroneous determinations of gaseous parts as liquid parts, enhancing the detection accuracy of liquid levels in refrigeration cycle apparatuses, even when liquid droplets are present, by using the first plate as a shielding mechanism.
Implementation Method 1
a heating resistor mounted to a lower end portion of the supporter, and a voltmeter configured to measure a voltage applied across both ends of the heating resistor... the liquid level is detected on the basis of the voltage value that differs depending on whether or not the heating resistor (heat generating element) is immersed through the liquid surface
Implementation Method 2
a capacitance sensor including electrode plates facing each other, the electrode plates being immersed into refrigerant in a liquid receptor, and a capacitance conversion unit that converts a capacitance detection value of the capacitance sensor into an oscillation frequency
Implementation Method 3
an ultrasonic sensor array consisting of a plurality of ultrasonic sensors arranged in a row mounted to a side surface of a receiver or an accumulator of an air-conditioning apparatus, the liquid level detection sensor determining the presence or absence of the liquid refrigerant on the basis of the received ultrasonic signal
Implementation Method 4
a laser beam projecting device that projects a laser beam on a liquid surface at a given angle and an optical sensor that receives the laser beam incident on the liquid surface and refracted in the liquid
Data Source
AI summary
A liquid level detection device that is provided in a vessel and configured to detect a liquid level of fluid stored in the vessel includes a first plate formed in a plate shape, and a second plate formed in a plate shape and disposed to face the first plate. The first plate is disposed in such a manner that a surface opposite to a surface facing the second plate is orthogonal to a flow direction of fluid around the first plate in the vessel.