Refrigerating Device Bypass Flow Control to Prevent Compressor Burnout
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Solution Overview
Problem
Refrigerating devices in environmental testing apparatuses and refrigerators face issues with excessive heat generation, leading to compressor burnout and reduced reliability due to motor heat, viscosity decrease, and early oil deterioration during long-term operation.
Innovation Solution
A refrigerating device with a bypass flow path connecting the condenser discharge and compressor suction, featuring a flow rate control mechanism that adjusts coolant flow to maintain a target temperature based on suction-side pressure, coolant amount, or refrigerating capacity, ensuring the compressor is neither overheated nor overcooled.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the refrigerating device operates continuously under harsh conditions, then the cooling capacity is maintained, but the motor generates excessive heat causing burnout and oil deterioration
Solution Approach 1:
The patent introduces a coolant as an intermediary substance that transfers heat from the motor to the suction side of the compressor. The coolant circulates through a cooling passage formed in the compressor, absorbing motor heat and transporting it to the suction side where it can be dissipated, thereby preventing motor overheating and improving reliability
Solution Approach 2:
The patent utilizes the refrigerant circulation system (pneumatic/hydraulic system) to solve the heat dissipation problem. By directing the coolant (refrigerant) through the compressor's cooling passage, the system leverages the existing fluid circulation to remove heat from the motor without requiring a separate cooling system
2Temperature
If the coolant flow rate is increased to cool the compressor, then the motor temperature decreases, but the compressor becomes too cold affecting operation
Solution Approach 1:
The patent employs feedback control by monitoring the temperature of the coolant before it enters the compressor and adjusting the opening degree of the expansion valve accordingly. When the coolant temperature is low (indicating sufficient cooling), the expansion valve opening is reduced to decrease coolant flow; when the temperature is high, the opening is increased to enhance cooling, thereby maintaining optimal compressor temperature
Solution Approach 2:
The system dynamically adjusts the coolant flow rate to the compressor based on real-time temperature conditions. The expansion valve opening degree is continuously modified in response to temperature changes, ensuring the compressor receives appropriate cooling without becoming excessively cold, thus maintaining operational stability
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 configuration effectively suppresses excessive heat generation and prevents compressor burnout by optimizing coolant flow, maintaining the compressor within a stable temperature range and enhancing the reliability of environmental testing apparatuses and refrigerators.
Implementation Method 1
During the evaporation by the evaporator, the coolant takes heat from the surrounding for cooling
Implementation Method 2
the coolant is compressed by the compressor, is condensed by the condenser
Data Source
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AI summary
A refrigerating device includes a refrigerating circuit and a control portion. The refrigerating circuit includes a main flow path in which a compressor, a condenser, an expansion portion, and an evaporator are connected to each other, and a bypass flow path that connects a discharge side of the condenser and a suction side of the compressor, and a flow rate control portion is provided in the bypass flow path. The control portion is configured to set a target temperature of a coolant introduced into the compressor according to a pressure of the coolant on the suction side of the compressor and is configured to change an opening degree of the flow rate control portion such that a temperature of the coolant introduced into the compressor becomes the target temperature. The target temperature when the pressure is high is higher than that when the pressure is low.