Screw Compressor Inlet Valve Delay Control for Temperature Peak Prevention
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Solution Overview
Problem
Existing liquid injected screw compressors experience undesired temperature peaks during the transition from an unloaded to a loaded state due to sudden changes in energy supply and low injection pressure, which can lead to compressor failure, and existing solutions are complex and not frequently applied.
Innovation Solution
A controller that delays the opening of the inlet valve until the injection pressure reaches a minimum threshold, allowing the pressure in the pressure vessel to gradually increase, ensuring the inlet valve opens only when the injection pressure is sufficient to prevent temperature peaks, and this can be determined experimentally or through algorithms based on compressor characteristics and operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the inlet valve is immediately fully opened during transition from unloaded to loaded state, then the reaction time is short and productivity is improved, but temperature peaks occur due to sudden energy supply and low injection pressure
Solution Approach 1:
The controller delays opening the inlet valve until the injection pressure reaches a predetermined minimum threshold value. This preliminary action ensures that sufficient liquid injection pressure is established before allowing gas intake, preventing temperature peaks and compressor failure while maintaining quick response time.
Solution Approach 2:
The controller continuously monitors the injection pressure and uses this feedback to determine the appropriate moment to open the inlet valve. When the injection pressure reaches the minimum threshold, the controller activates the inlet valve, creating a closed-loop control system that prevents temperature peaks while minimizing delay.
2Use of energy by moving object
If the injection pressure is kept as low as possible when unloaded, then energy consumption is reduced, but temperature peaks occur when the inlet valve opens suddenly due to insufficient injection pressure
Solution Approach 1:
The system maintains low injection pressure during unloaded operation to minimize energy consumption, but the controller is programmed to delay inlet valve opening until the injection pressure naturally rises to a minimum threshold. This preliminary preparation ensures that when the valve does open, sufficient injection pressure is available to prevent temperature peaks.
Solution Approach 2:
The controller dynamically changes the operational parameters by monitoring injection pressure and only permitting inlet valve opening when the pressure reaches a predetermined threshold. This parameter-based control allows the system to maintain low energy consumption during idle periods while ensuring safe operational parameters are met before loading.
3Reliability
If a delay is introduced before opening the inlet valve to build up injection pressure, then temperature peaks are prevented, but the reaction time increases
Solution Approach 1:
The controller continuously monitors injection pressure and uses this feedback to determine the precise moment when the threshold is reached, allowing the inlet valve to open immediately at that moment. This feedback mechanism minimizes the delay to only the time required for pressure to naturally build up to the threshold, rather than imposing an arbitrary fixed delay.
Solution Approach 2:
The system uses dynamic pressure monitoring to adjust the timing of inlet valve opening based on actual injection pressure conditions. Rather than a fixed delay, the valve opens dynamically when the pressure threshold is achieved, optimizing the balance between preventing temperature peaks and minimizing reaction time.
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 prevents compressor failure by ensuring the injection pressure is above a safe minimum before fully opening the inlet valve, allowing for a quicker pressure build-up in the consumer network and reducing the risk of temperature peaks, while maintaining energy efficiency.
Implementation Method 1
a liquid separator provided in the pressure pipe to separate liquid from the compressed gas
Implementation Method 2
a liquid circuit with an injector for injecting liquid into the compressor element
Data Source
AI summary
Liquid injected screw compressor with an inlet valve and blow-off valve; a liquid circuit with injector; a controller for the transition from unloaded to loaded, whereby when unloaded the inlet valve is closed and the blow-off valve is open, and when loaded the inlet valve is open and the blow-off valve is closed, and whereby during an aforementioned transition, when the injection pressure is below a minimum threshold, the inlet valve remains closed and is opened with a certain delay and that there are means to gradually increase the injection during this delay and to open the inlet valve when the injection pressure has reached the minimum threshold.