Freezing apparatus
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Solution Overview
Problem
The existing refrigeration apparatuses face challenges in accurately determining the flow of gas refrigerant through the oil return pipe due to variations in temperature measurements caused by factors other than the state of the fluid, leading to potential inaccuracies in detection.
Innovation Solution
A refrigeration apparatus with a discharge temperature sensor and a controller that adjusts the opening degree of the oil return valve to detect gas refrigerant flow based on temperature changes, ensuring the change in measurement is solely due to the valve's opening degree, thereby enhancing detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If temperature difference between discharge sensor and connection pipe sensor is used to detect gas refrigerant flow, then detection capability is provided, but measurement accuracy deteriorates due to multiple influencing factors
Solution Approach 1:
The invention extracts the temperature measurement function from the connection pipe and uses only the discharge temperature sensor to detect gas refrigerant flow. By removing the second temperature sensor from the connection pipe and eliminating the temperature difference calculation, the system eliminates the measurement errors caused by multiple influencing factors while retaining the ability to detect gas refrigerant flow through discharge temperature changes alone.
Solution Approach 2:
The invention introduces the oil return valve opening degree change as an intermediary control mechanism. By actively changing the valve opening degree and observing the resulting discharge temperature changes, the system creates a controlled measurement scenario where the temperature change is directly attributable to the valve action and gas refrigerant flow, rather than multiple uncontrolled factors.
2Loss of information
If multiple temperature sensors are used to monitor refrigerant state, then measurement coverage is improved, but system complexity increases
Solution Approach 1:
The invention removes the second temperature sensor from the connection pipe, reducing the sensor count from two to one. This extraction eliminates the complexity of synchronizing multiple sensors, calculating temperature differences, and managing multiple data streams, while the single discharge temperature sensor continues to provide sufficient information for gas refrigerant flow detection when used with oil return valve control.
3Difficulty of detecting and measuring
If temperature difference method is used for detection, then detection function is achieved, but reliability deteriorates due to external factors
Solution Approach 1:
The invention implements a feedback control loop where the controller changes the oil return valve opening degree, monitors the resulting discharge temperature changes via the discharge temperature sensor, and uses this feedback to reliably determine gas refrigerant flow. This active feedback mechanism ensures that the detection is based on controlled, observable changes rather than passive temperature difference measurements that are susceptible to external factors.
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
Accurate detection of gas refrigerant flow in the oil return pipe, maintaining high refrigerant flow rates and preventing compressor damage by ensuring adequate lubrication, while optimizing operation and reducing unnecessary recovery operations.
Implementation Method 1
a discharge temperature sensor (50) configured to measure the temperature of the gas refrigerant discharged from the compression mechanism (32)
Implementation Method 2
an oil return valve (46) provided for the oil return pipe (45)
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A compressor unit (20) of a refrigerant circuit (15) includes a compressor (30), an oil separator (40), an oil return pipe (45), an oil return valve (46), and a discharge temperature sensor (50). A refrigeration apparatus (10) includes a controller (60). The controller (60) performs a detection operation. The detection operation is an operation of decreasing the opening degree of the oil return valve (46) and detecting whether or not gas refrigerant is flowing through the oil return pipe (45) based on a change in the measured value by the discharge temperature sensor (50) after the decreasing of the opening degree of the oil return valve (46) as compared to the measured value by the discharge temperature sensor (50) before the decreasing of the opening degree of the oil return valve (46).