Screw Compressor Valve Disc Drive Reduces Over-Compression
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Solution Overview
Problem
Conventional screw compressors experience hammering sound and vibration due to the repeated opening and closing of the valve disc caused by pressure equilibrium, leading to ineffective reduction of over-compression.
Innovation Solution
A screw compressor design that includes a valve disc drive device with a piston and cylinder system, controlled by a solenoid valve and spring mechanism, which opens and closes the valve disc based on pressure ratios detected by sensors, ensuring the valve disc remains fully open or closed to prevent pressure-induced oscillation and reduce over-compression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the valve disc is controlled to open and close based on pressure equilibrium, then the over-compression is reduced, but the valve disc experiences repeated oscillation causing hammering sound and vibration
Solution Approach 1:
The control device opens the valve disc in advance when over-compression is detected, before the pressure equilibrium causes oscillation. This preliminary action allows the valve disc to remain open during the critical compression phase, preventing the repeated opening and closing that causes hammering sound and vibration while still achieving over-compression reduction.
Solution Approach 2:
The control device continuously monitors the pressure ratio between the compression operation chamber and discharge chamber, and adjusts the valve disc position based on this feedback. When the pressure ratio indicates over-compression, the control device maintains the valve disc in the open position, preventing oscillation and ensuring stable operation while reducing energy loss.
2Loss of energy
If the valve disc is kept open to reduce over-compression, then the compressed gas can escape, but the valve disc may not close properly causing incomplete compression
Solution Approach 1:
The valve disc position is dynamically adjusted based on real-time pressure ratio detection. The control device opens the valve disc when over-compression is detected and closes it when the pressure ratio returns to normal levels. This dynamic control ensures that the valve disc remains open only when necessary to reduce over-compression, while maintaining proper compression efficiency during normal operation.
Solution Approach 2:
The control device changes the valve disc position parameter based on the pressure ratio parameter. When the pressure ratio exceeds a predetermined threshold indicating over-compression, the valve disc is opened. When the pressure ratio returns to normal, the valve disc is closed. This parameter-based control ensures optimal balance between over-compression reduction and compression efficiency.
3Device complexity
If a simple spring mechanism is used for valve disc actuation, then the device complexity is reduced, but the valve disc cannot respond sufficiently to pressure changes causing oscillation
Solution Approach 1:
The patent replaces the simple mechanical spring mechanism with an electronically controlled valve disc drive device. The control device uses pressure ratio detection and electronic control to actuate the valve disc, providing more precise and reliable response to pressure changes. This substitution eliminates the oscillation problem while maintaining acceptable device complexity through integrated control.
Solution Approach 2:
The control device acts as an intermediary between the pressure sensors and the valve disc drive mechanism. It processes the pressure ratio information and translates it into appropriate valve disc position commands, providing intelligent mediation that ensures stable valve disc operation and prevents oscillation while managing system complexity.
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
The solution effectively reduces the degree of over-compression, minimizes hammering sound and vibration, and enhances the reliability of the valve disc operation by maintaining consistent valve disc position, thereby reducing unnecessary motive power consumption and improving compressor performance.
Implementation Method 1
The valve device includes a valve disc and a spring (pressing spring). The spring presses the valve disc toward the main casing.
Implementation Method 2
a control device that detects whether the compression operation chamber is over-compressed, and if the compression operation chamber is over-compressed, controls the valve disc drive device so as to open the valve disc
Data Source
Figure 1
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AI summary
A screw compressor having a discharge casing (16). The discharge casing (16) includes a discharge side end face that abuts on an end face of a main casing (15) to cover the opening of a bore (20), a discharge port (23A, 23B; 25A, 25B) that is formed on the discharge side end face, a discharge chamber (26) that discharges a compressed gas from a compression operation chamber (36A, 36B) through the discharge port (23A, 23B; 25A, 25B), a valve hole (28) that is disposed near the discharge port (23A, 23B; 25A, 25B) on the female rotor side of the discharge side end face and open at a position opposite the direction of female rotor rotation, a bypass groove (29) that permits the valve hole (28) to communicate with a discharge flow path, and a valve disc (31) that is disposed in the valve hole (28). The screw compressor also includes a valve disc drive device (30) that opens and closes the valve disc (31), and a control device (112) that detects whether the compression operation chamber (36A, 36B) is over-compressed, and if the compression operation chamber (36A, 36B) is over-compressed, controls the valve disc drive device (30) so as to open the valve disc (31).