Centrifugal Separator Motor Inductive Heating for Cold Startup
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Solution Overview
Problem
Centrifugal separators used to clean gas from internal combustion engines face difficulties in starting up at low temperatures due to increased oil viscosity, which causes resistance and makes it hard to rotate the rotor, especially when oil adheres to the motor components.
Innovation Solution
A method involving an electric motor with a stator and rotor, where the stator is controlled to generate an oscillating magnetic field at high frequencies (above 10 kHz) to heat the surroundings without rotating the rotor, reducing oil viscosity and facilitating startup, by using the motor's hardware for inductive heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the centrifugal separator is started up at low temperatures, then the separator can begin operation, but the increased oil viscosity causes resistance that makes it difficult to rotate the rotor
Solution Approach 1:
The patent applies preliminary action by heating the oil surrounding the rotor before startup using high-frequency magnetic fields generated by the stator. This pre-heating reduces oil viscosity in advance, eliminating the resistance that would otherwise prevent rotor rotation at low temperatures.
Solution Approach 2:
The patent changes the physical state of the oil by using high-frequency magnetic fields (above 10 kHz) to induce heating, thereby changing the temperature and viscosity parameters of the oil from a high-viscosity cold state to a low-viscosity warm state, enabling rotor rotation.
2Temperature
If the stator generates high-frequency oscillating magnetic field to heat the surroundings, then the oil viscosity decreases and startup becomes easier, but the rotor does not rotate during heating
Solution Approach 1:
The patent uses periodic action by first applying high-frequency magnetic fields for a specific heating period to raise the temperature of surrounding oil, then switching to normal rotation mode. This time-separated periodic action ensures heating occurs without interference from rotor rotation, and rotation occurs only after heating is complete.
Solution Approach 2:
The heating phase serves as a preliminary action that prepares the system by reducing oil viscosity before the actual rotor rotation begins. This sequential approach ensures that when rotation starts, the oil offers minimal resistance.
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 method effectively lowers the viscosity of oil around the rotor, making it easier to start the centrifugal separator in cold conditions by heating the surroundings through inductive heating, ensuring proper operation and efficiency.
Implementation Method 1
controlling the stator to expose the rotor to a first oscillating magnetic field that increases the temperature of the surroundings of the electric motor without rotating the rotor
Implementation Method 2
The first oscillating magnetic field has a frequency of above 5 kHz, such as above 15 kHz
Implementation Method 3
When the temperature of the oil is low its viscosity increases. Thus, at startup of the centrifugal separator in conditions of low temperature, any oil that has previously been separated from gas but not drained from the separator may adhere to the rotatable portions of the separator, making it harder to start
Data Source
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AI summary
The present invention provides an apparatus and a method (100) for controlling an electric motor (30) of a centrifugal separator (1) for cleaning gas containing contaminants. The centrifugal separator (1) is comprising a stationary casing (2), enclosing a separation space (3) through which a gas flow is permitted, a rotatable member (7) comprising a plurality of separation members (9) arranged in said separation space (3) and being arranged to rotate around an axis (X) of rotation. The electric motor (30) comprises a stator (31) and a rotor (32) and is arranged for rotating said rotatable member (7). The method (100) comprises a step of controlling (101) the stator (31) to expose the rotor (32) to a first oscillating magnetic field that increases the temperature of the surroundings of the electric motor (31) without rotating the rotor (32).