Oil-cooled Screw Compressor Asymmetric Discharge Port
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Solution Overview
Problem
In oil-cooled screw compressors, the high discharge resistance of oil leads to increased torque and energy consumption due to its high density and viscosity, causing performance degradation by generating significant resistance at the discharge port, which is not effectively addressed by existing tooth profiles.
Innovation Solution
The design features a screw rotor with a twisted tooth profile where most male rotor teeth are outside the male pitch circle and most female rotor teeth are inside the female pitch circle, with a discharge port contour that allows smooth oil discharge by reducing the opening area only in the lower half region, minimizing resistance and maintaining efficient energy usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oil is injected into the operation chamber for lubrication, sealing, and cooling functions, then the reliability and lubrication performance are improved, but the discharge resistance increases significantly due to high density and viscosity
Solution Approach 1:
The invention applies local quality by creating an asymmetric discharge port configuration where the opening area is selectively reduced only in the lower half region rather than uniformly across the entire discharge port. This localized modification optimizes oil discharge pathways while maintaining adequate flow area, directly addressing the high discharge resistance caused by oil's density and viscosity without compromising lubrication performance.
Solution Approach 2:
The invention employs asymmetry by configuring the discharge port with different opening areas in the upper and lower half regions. The contour line extending to the male rotor side is positioned differently from the contour line extending to the female rotor side, creating an asymmetric flow path that facilitates smoother oil discharge and reduces resistance while maintaining the discharge port's overall sealing function.
2Use of energy by moving object
If the opening area of the discharge port is reduced to minimize oil discharge resistance, then the energy efficiency is improved, but the discharge capability may be compromised
Solution Approach 1:
The invention applies local quality by creating an asymmetric discharge port configuration where the opening area is selectively reduced only in the lower half region rather than uniformly across the entire discharge port. This localized modification optimizes oil discharge pathways while maintaining adequate flow area, directly addressing the high discharge resistance caused by oil's density and viscosity without compromising lubrication performance.
Solution Approach 2:
The invention employs asymmetry by configuring the discharge port with different opening areas in the upper and lower half regions. The contour line extending to the male rotor side is positioned differently from the contour line extending to the female rotor side, creating an asymmetric flow path that facilitates smoother oil discharge and reduces resistance while maintaining the discharge port's overall sealing function.
3Force
If the tooth profile is designed with most male teeth outside the pitch circle and most female teeth inside the pitch circle, then the oil discharge resistance is reduced and torque is lowered, but the manufacturing precision requirements increase
Solution Approach 1:
The invention applies spheroidality by defining the tooth profiles using circular arcs centered at the rotor axes rather than traditional involute curves. The male rotor tooth profile consists of a circular arc extending from the front tooth tip point to the rear tooth tip point, and the female rotor tooth profile uses a corresponding circular arc configuration. This curved geometry simplifies manufacturing while achieving the desired oil discharge characteristics and torque reduction.
Solution Approach 2:
The invention applies parameter changes by specifying precise geometric parameters for the tooth profiles, including the positions of front and rear tooth tip points, the radii of circular arcs, and the relationships between tooth profiles and pitch circles. These parameter specifications enable standardized manufacturing processes while achieving the optimized discharge port configuration and reduced torque.
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 configuration reduces the driving torque and improves energy efficiency by ensuring smooth oil discharge, reducing power consumption and enhancing the overall performance of the screw compressor.
Implementation Method 1
a screw rotor which has a pair of a male rotor (1) and a female rotor (2) rotating by meshing with each other around two parallel axes and each having twisted teeth
Implementation Method 2
A first function is a lubricant that helps the rotation transmission due to contact between the female and male rotors
Implementation Method 3
a second function is a sealant that reduces the internal leakage of the gas to be compressed for filling the gap between the rotors
Implementation Method 4
a third function is a coolant for the gas to be compressed which increases in temperature by compression
Implementation Method 5
the contour line extending from the base point to the male rotor side is located on a locus line when the tooth tip of the male rotor facing the base point is reversely rotated or to be closer to the center of the male rotor tooth profile than the locus line
Data Source
AI summary
In an oil-cooled screw compressor, a tooth crest arc of a fixed width is provided to the tooth crest of a male tooth profile, and simultaneously a tooth bottom arc is provided to the tooth bottom of a female tooth profile. Due to the actions thereof, the operation chamber immediately before disappearing exists only in a bottom half region from a line that connects the centers of the male and female tooth profiles, and the opening area relative to the volume of the operation chamber can be increased. As a result, the discharge of oil becomes smooth and energy loss is reduced.