Screw Compressor Suction Line Backflow Prevention
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Solution Overview
Problem
Existing liquid-injected screw compressors face inefficiencies due to backflow of compressed air from the liquid separator into the compressor block, which reduces efficiency and reliability, and existing solutions inadequately address this issue.
Innovation Solution
A compressor system with a controllable valve and media change sensor that detects the transition from liquid to compressed air in the suction line, allowing the valve to block the suction line when compressed air is detected, preventing backflow and allowing larger cross-section and pressure gradients for improved reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cross-section of the suction line is reduced to extract oil, then oil extraction is improved, but compressed air backflow increases and compressor efficiency deteriorates
Solution Approach 1:
The suction line cross-section is made dynamically adjustable through a control system that opens or closes the line based on operating conditions. The control unit monitors parameters such as pressure differential and compressor speed, and actuates a valve or bypass mechanism to dynamically adjust the suction line opening, thereby optimizing both oil extraction and preventing compressed air backflow at different operating points
Solution Approach 2:
The system changes the flow parameters (cross-section area, flow rate) of the suction line based on detected operating conditions. By monitoring pressure differential across the separator and compressor speed, the control system adjusts the suction line opening degree to maintain optimal parameters for oil extraction while preventing harmful backflow that would reduce compressor efficiency
2Reliability
If the suction line cross-section is made large enough to prevent clogging, then reliability is improved, but compressed air backflow increases and efficiency deteriorates
Solution Approach 1:
Rather than using a permanently large cross-section, the system employs a dynamically controllable suction line with adjustable opening area. The control system adjusts the effective cross-section in real-time based on operating conditions, maintaining a large enough opening to prevent clogging when needed while minimizing the opening during normal operation to prevent energy loss from compressed air backflow
3Reliability
If pressure drop is reduced to improve oil extraction, then oil separation is improved, but compressed air backflow increases and efficiency deteriorates
Solution Approach 1:
The system dynamically adjusts the pressure differential parameter across the suction line based on operating conditions. The control unit monitors pressure at different points and adjusts the suction line opening to maintain an optimal pressure drop that enables reliable oil separation while preventing excessive pressure differential that would cause compressed air backflow and efficiency 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
This solution effectively prevents the backflow of compressed air into the compressor block, enhancing efficiency and reliability by ensuring the suction line is only open when liquid is being extracted, and eliminating the need for check valves, thus reducing operational issues and improving overall compressor performance.
Implementation Method 1
a media change sensor for detecting a media change of a medium flowing in the suction line, namely from sucked-in liquid to compressed air
Implementation Method 2
a controllable valve for regulating the flow rate through the suction line
Implementation Method 3
a suction line for sucking liquid from at least one suction point of the fine separator to a feed point
Data Source
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AI summary
The disclosure relates to a compressor (100), in particular a screw compressor, for generating compressed air, and to a method for controlling such a compressor (100). The compressor (100) comprises a compressor block (4) with liquid injection for compressing intake air, a liquid separator (5) connected to the compressor block (4) via a pressure line (52) and comprising a separator tank (6) and a fine separator (7), a return line (53) for returning separated liquid from the separator tank (6) to the compressor block (4), a suction line (56) for extracting liquid from at least one suction point (33) of the fine separator (7) to a supply point (34) in order to supply the extracted liquid to the compressor block (4), a controllable valve (19) for regulating the flow rate through the suction line (56), and a control unit (60) for controlling the valve (19).and a media change sensor (18) for detecting a media change of a medium flowing in the extraction line (56), in particular from extracted liquid to compressed air, which is connected to the control unit (60).