Compressor Crankcase Heating for Flooded-Start Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Compressors in refrigeration systems face operational issues due to flooding with liquid refrigerant, which dissolves lubricant, leading to mechanical damage and reduced reliability, as the compressor pumps out the liquid refrigerant quickly, leaving it un lubricated and potentially causing premature wear.
Innovation Solution
A system comprising a duct assembly with a sensor unit and control module that heats and evaporates refrigerant from the lubricant sump, determining the presence of liquid refrigerant by comparing actual and expected temperature changes, ensuring the compressor operates only when the refrigerant is fully evaporated, thus maintaining lubrication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the compressor starts in a flooded state with liquid refrigerant, then the compressor can quickly pump out the liquid refrigerant, but the compressor operates without lubrication causing mechanical damage
Solution Approach 1:
The crankcase heater is activated before compressor startup to heat the crankcase and evaporate liquid refrigerant from the lubricant sump. This preliminary action prevents flooding by removing liquid refrigerant before the compressor begins operation, ensuring the compressor starts with adequate lubrication and avoiding mechanical damage.
Solution Approach 2:
The control system monitors crankcase temperature and uses this feedback to control the crankcase heater operation. When the crankcase temperature indicates the presence of liquid refrigerant or low temperature conditions, the heater is activated. The system continuously adjusts heater operation based on temperature feedback to maintain proper lubrication conditions without overheating.
2Loss of time
If the compressor operates without lubrication to quickly remove liquid refrigerant, then the liquid refrigerant is pumped out faster, but the compressor moving parts suffer premature wear
Solution Approach 1:
The system performs preliminary heating of the crankcase before compressor startup to evaporate liquid refrigerant from the lubricant sump. This advance action eliminates the need to operate without lubrication, as the liquid refrigerant is removed beforehand through controlled evaporation using the crankcase heater.
Solution Approach 2:
The system converts the harmful presence of liquid refrigerant in the crankcase into a beneficial process by using controlled evaporation. The crankcase heater applies heat to evaporate the liquid refrigerant, and the control system manages this evaporation process to occur before startup, transforming the potential harm of flooding into a controlled phase change that protects the compressor.
3Stability of the object's composition
If the compressor lubricant dissolves in liquid refrigerant, then the lubricant becomes part of the liquid mixture, but the compressor loses effective lubrication leading to mechanical damage
Solution Approach 1:
The crankcase heater is activated before compressor startup to heat the crankcase and evaporate liquid refrigerant from the lubricant sump. This preliminary action prevents the lubricant from dissolving in liquid refrigerant by removing the liquid refrigerant through evaporation before the compressor begins operation, maintaining lubricant integrity and effectiveness.
Solution Approach 2:
The system changes the temperature parameter of the crankcase by activating the crankcase heater. This temperature increase causes the liquid refrigerant to evaporate from the lubricant sump, preventing dissolution of the lubricant in liquid refrigerant. The control system manages the temperature parameter to achieve complete evaporation before startup.
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
Prevents mechanical damage by ensuring the compressor operates with adequate lubrication, extending its lifespan and reliability by ensuring the refrigerant is fully evaporated before starting the compressor.
Implementation Method 1
the sensor unit is configured to heat and evaporate the refrigerant located within the duct frame of the duct assembly
Implementation Method 2
heat and evaporate the refrigerant located within the duct frame of the duct assembly
Data Source
AI summary
A refrigeration system includes compressor and a duct assembly that includes a duct frame and a sensor unit. The duct frame provides a path for evaporating refrigerant from a lubricant sump of the compressor. The sensor unit obtains temperature measurements of the refrigerant and a lubricant within the lubricant sump and heats and evaporates the refrigerant located within the duct frame of the duct assembly. A control module receives temperature measurements from the sensor unit, determines a presence of liquid refrigerant within the lubricant sump of the compressor in response to a determination that an actual temperature change does not correspond with an expected temperature change for the lubricant, and in response to a determination that the actual temperature change corresponds with the expected temperature change for the lubricant, operates the compressor.