Oil separator
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Solution Overview
Problem
In refrigeration circuits with ejectors, oil used for lubricating the compressor dissolves into the refrigerant and accumulates in the liquid phase, leading to a loss of oil in the suction circuit, which can cause the compressor to run dry if not adequately replaced.
Innovation Solution
An oil separation device is integrated into the suction circuit between the evaporator and the ejector, utilizing a refrigerant conduit with an enlarged diameter to separate oil from the refrigerant flow, and a low-pressure refrigerant return line to extract and transfer the collected oil back to the compressor, eliminating the need for additional pumps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oil is used for lubricating the compressor, then the compressor can operate reliably, but the oil dissolves into the refrigerant and accumulates in the liquid phase, causing oil loss in the suction circuit
Solution Approach 1:
The invention extracts oil from the liquid refrigerant phase using a dedicated oil separation device. The separation device includes a oil separation chamber where oil and refrigerant are separated based on density differences, and an oil return line that extracts the separated oil and returns it to the compressor, thereby preventing oil loss in the suction circuit
Solution Approach 2:
The invention implements a feedback mechanism by returning the separated oil from the liquid phase back to the compressor through an oil return line. This closed-loop feedback ensures that oil continuously circulates between the compressor and the separation device, maintaining adequate oil levels in the compressor and preventing oil loss
2Loss of substance
If a pump is added to transfer oil back to the compressor, then oil can be recovered and re-transferred, but the device complexity and cost increase
Solution Approach 1:
The invention uses the existing refrigerant circulation system to serve the oil return function. The low-pressure refrigerant flow naturally creates a suction effect that draws separated oil from the liquid phase and transports it back to the compressor without requiring an additional pump. This self-service approach leverages the refrigerant flow to perform the oil return function
Solution Approach 2:
The invention merges the oil return function with the existing refrigerant circulation system. The oil separation device is integrated into the liquid line, and the oil return line utilizes the low-pressure refrigerant flow path. By combining these functions, the system avoids adding a separate pump and reduces overall device complexity
3Quantity of substance
If oil accumulates in the liquid phase of refrigerant, then oil separation is needed, but without proper separation the compressor will run dry and be damaged
Solution Approach 1:
The invention extracts oil from the liquid refrigerant phase using a dedicated oil separation device. The separation device includes a oil separation chamber where oil and refrigerant are separated based on density differences, and an oil return line that extracts the separated oil and returns it to the compressor, thereby preventing oil loss in the suction circuit
Solution Approach 2:
The invention implements a feedback mechanism by returning the separated oil from the liquid phase back to the compressor through an oil return line. This closed-loop feedback ensures that oil continuously circulates between the compressor and the separation device, maintaining adequate oil levels in the compressor and preventing oil loss
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
Effectively recovers and re-transfers oil from the suction circuit to the driving circuit, preventing compressor dry-running and maintaining lubrication, while reducing costs and complexity by using existing refrigerant flow for pressure reduction.
Implementation Method 1
supplying the refrigerant-oil-mixture to a first refrigerant conduit (15) having a first portion (16) with an enlarged diameter and a second portion (18) with a smaller diameter... oil flows at the wall of the first refrigerant conduit as a ring current
Implementation Method 2
oil accumulates in the liquid portion of the refrigerant collected in the gas-liquid separator
Implementation Method 3
a low-pressure refrigerant return line (24) reducing the pressure in order to suck the oil from the oil separation pocket (32) into the separation vessel (22)
Implementation Method 4
an ejector which is configured for expanding refrigerant coming from a heat rejecting heat exchanger arranged downstream of a compressor and for sucking gas-phase refrigerant from an evaporator at the same time. The ejector increases the suction pressure of a compressor by converting expansion energy into pressure energy
Implementation Method 5
a compressor 2... Said gaseous refrigerant is compressed by the compressor 2 to a high pressure of e.g. 90 - 95 bar
Data Source
Figure 1
Figure 2
AI summary
An oil separation device (14) for separating oil from a refrigerant-oil-mixture in a refrigeration cycle (1), the oil separation device (14) comprises a first refrigerant conduit having at least a first portion (16) with a first diameter (dl); a second refrigerant conduit arranged downstream of and connected to the first refrigerant conduit, the second refrigerant conduit having at least a second portion with a second diameter (d2) being smaller than the first diameter (dl); wherein the second portion (18) of the second refrigerant conduit having the second diameter (d2) extends into the first portion (16) of the first refrigerant conduit forming an oil separation pocket (32) between the outer diameter of the second portion (18) and the inner diameter of the first portion (16); and a suction line (20) having an inlet end (19), which opens into the oil separation pocket (32) and is configured to suck oil from the oil separation pocket (32).