Compressor Motor Cooling Using Suction-Induced Gas Sweep
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing motor cooling methods for large capacity gas compression systems, such as refrigeration systems, face inefficiencies due to high refrigerant gas flow requirements, which reduce system efficiency and pose risks of erosion to motor parts, while current gas-phase cooling methods are not effective in cooling specific motor areas like the air gap and rotor area.
Innovation Solution
A system and method that divert part of the uncompressed gas flow into the motor housing prior to compression, using a pressure reduction means like a converging nozzle or venturi to create a pressure differential, allowing for efficient cooling of motors without significant system efficiency loss, and combining this with liquid cooling for enhanced cooling of targeted areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If high flow rates of refrigerant gas are used for motor cooling, then motor cooling effectiveness is improved, but system efficiency is reduced and erosion risk to motor parts increases
Solution Approach 1:
The invention changes the pressure parameter of the refrigerant gas by introducing a pressure reducing device that creates a pressure differential. This allows cooling gas to be drawn from the high-pressure discharge side and delivered to the motor at a reduced pressure, maintaining cooling effectiveness while reducing the harmful effects of high flow rates
Solution Approach 2:
The pressure reducing device acts as an intermediary between the discharge line and the motor cooling system. It mediates the transition from high-pressure discharge gas to the appropriate pressure for motor cooling, enabling efficient cooling without the negative effects of high-pressure gas flow
2Temperature
If high flow rates of refrigerant gas are used for motor cooling, then motor cooling effectiveness is improved, but erosion risk to motor parts increases
Solution Approach 1:
By reducing the pressure of the cooling gas through the pressure reducing device, the velocity and kinetic energy of the gas flow are reduced. This maintains the cooling effect while minimizing the erosive impact on motor components such as the impeller and diffuser
3Device complexity
If gas-phase cooling methods are used, then system complexity is reduced, but cooling effectiveness in specific motor areas like air gap and rotor area is insufficient
Solution Approach 1:
The cooling system is segmented into multiple pathways: a first pathway delivers pressurized cooling gas to the motor housing, and a second pathway delivers reduced-pressure cooling gas directly to the air gap region. This segmentation allows targeted cooling of different motor areas without significantly increasing overall system complexity
Solution Approach 2:
Different regions of the motor receive cooling gas with different pressure characteristics. The air gap region receives lower-pressure gas that is better suited for penetrating and cooling this specific area, while other motor regions receive appropriately pressurized cooling gas, optimizing cooling effectiveness for each location
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 approach improves motor cooling in large capacity systems without compromising efficiency, effectively cooling the motor through the circulation of refrigerant gas and additional liquid coolant, addressing the limitations of existing methods by reducing gas flow requirements and minimizing erosion risks.
Implementation Method 1
The pressure reduction necessary to draw the uncompressed gas through the motor housing is generated by pressure reduction means, such as a nozzle and gap, or alternatively a venturi
Implementation Method 2
the means for creating a pressure reduction includes a converging nozzle portion configured to accelerate flow of uncompressed refrigerant gas through the nozzle portion
Implementation Method 3
the means for creating a pressure reduction is a venturi
Implementation Method 4
the refrigerant is injected into the motor housing where it absorbs motor heat and rapidly evaporates or 'flashes' into gaseous form, thus cooling the motor
Implementation Method 5
the refrigerant is injected into the motor housing where it absorbs motor heat and rapidly evaporates or 'flashes' into gaseous form
Implementation Method 6
improves motor cooling in large capacity systems without compromising efficiency, effectively cooling the motor through the circulation of refrigerant gas
Data Source
AI summary
Apparatus and methods are provided for cooling motors used to drive gas and air compressors. In particular, the cooling of hermetic and semi-hermetic motors is accomplished by a gas sweep using a gas source located in the low-pressure side of a gas compression circuit. The gas sweep is provided by the creation of a pressure reduction at the compressor inlet sufficient to draw uncompressed gas through a motor housing, across the motor, and out of the housing for return to the suction assembly. The pressure reduction is created by structure in the suction assembly, such as a nozzle and gap assembly, or alternatively a venturi, located upstream of the compressor inlet. Additional motor cooling can be provided by circulating liquid or another cooling fluid through a cooling jacket in the motor housing portion adjacent the motor.