Multistage compression system
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In multistage compression systems, the uneven distribution of oil across compressors affects refrigerant circuit performance, particularly due to the placement of oil drain passages and pressure reducing elements, leading to variations in refrigerant and oil flow, which can result in insufficient cooling when a large amount of refrigerant bypasses the intercooler.
Innovation Solution
The oil discharge pipe connects the low-stage compressor to the refrigerant pipes upstream of the pressure reducing element, such as an intercooler or merging point of an intermediate injection passage, to control the amount of oil discharged and maintain appropriate oil levels in the low-stage compressor, thereby stabilizing refrigerant circuit operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the oil discharge pipe connects to the refrigerant pipe downstream of the pressure reducing element, then the oil can be discharged from the low-stage compressor, but the amount of refrigerant and oil passing through the oil drain passage varies greatly, affecting refrigerant circuit performance and causing insufficient cooling
Solution Approach 1:
The oil discharge pipe is connected to the refrigerant pipe upstream of the pressure reducing element, performing the oil discharge action before the pressure reduction occurs. This preliminary positioning ensures that oil is discharged at a stable pressure point, preventing excessive refrigerant from bypassing the intercooler and causing insufficient cooling.
2Quantity of substance
If a large amount of refrigerant bypasses the intercooler, then the refrigerant flow increases, but the refrigerant cooling amount becomes insufficient
Solution Approach 1:
The oil discharge pipe acts as an intermediary element that regulates the flow of refrigerant and oil. By positioning it upstream of the pressure reducing element, it prevents excessive refrigerant from bypassing the intercooler, thereby maintaining adequate cooling while allowing necessary refrigerant flow through the system.
3Loss of substance
If the oil discharge amount is not controlled, then oil can be removed from the low-stage compressor, but the oil level becomes unevenly distributed, affecting the multistage compression system
Solution Approach 1:
The system utilizes the pressure difference created by the pressure reducing element to regulate oil discharge. By connecting the oil discharge pipe upstream of the pressure reducing element, the system creates a feedback mechanism where oil is discharged at a controlled rate based on the pressure differential, preventing both excessive discharge and insufficient oil level maintenance.
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 reduces the amount of oil discharged, allowing for precise control of oil levels in the low-stage compressor, enhancing refrigerant circuit efficiency and preventing insufficient cooling by ensuring consistent refrigerant flow and pressure.
Implementation Method 1
a pressure reducing element disposed between the refrigerant pipes
Implementation Method 2
an oil discharge pipe connecting the low-stage compressor, so that the oil discharge pipe discharges the oil
Data Source
Figure 1
Figure 2
Figure 3
AI summary
In a refrigeration apparatus using a plurality of multistage compressors, it has been necessary to keep an appropriate amount of refrigerator oil in each of the plurality of multistage compressors. A multistage compression system (20) has a low-stage compressor (21), a high-stage compressor (23), refrigerant pipes (151 to 156 and 16), pressure reducing elements (26 and 15b), and an oil discharge pipe (32). The refrigerant pipes (151 to 156 and 16) introduce refrigerant compressed and discharged by the low-stage compressor (21) into a suction part of the high-stage compressor (23). The pressure reducing elements (26 and 15b) are disposed in a middle of the intermediate pressure refrigerant pipes (151 to 156). The oil discharge pipe (32) discharges oil in the low-stage compressor (21). The oil discharge pipe (32) connects the low-stage compressor (21) and the refrigerant pipe upstream of the pressure reducing elements (26 and 15b).