Vane-Rotary Gas Compressor Back-Pressure Groove Design
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Solution Overview
Problem
In vane-rotary type gas compressors, excessive back-pressure leads to chattering and increased abrasion due to the leading end of the vane strongly rubbing the inner circumferential surface of the cylinder, particularly during high-speed operations.
Innovation Solution
The design includes a back-pressure-supplying groove with an increased sectional surface area between the vane groove and the drain groove, allowing for efficient oil flow and maintaining back-pressure at manageable levels by enlarging the communication portion before separation, and utilizing a high-pressure-supplying hole to match back-pressure with discharge pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the back-pressure in the vane groove is increased to prevent chattering of the vane, then the vane stability is improved, but the leading end portion of the vane strongly rubs the inner circumferential surface of the cylinder causing excessive abrasion
Solution Approach 1:
The invention divides the back-pressure control into two distinct phases: during compression process (using drain groove) and during discharge process (using enlarged communication portion). This segmentation allows optimized back-pressure for each phase, preventing both chattering and excessive abrasion.
Solution Approach 2:
The communication portion between the vane groove and drain groove is designed to dynamically change its sectional surface area during rotor rotation. It is small during compression to maintain stable back-pressure, and enlarges during discharge to reduce back-pressure and prevent excessive rubbing.
2Reliability
If the communication portion between the vane groove and drain groove is kept small to maintain back-pressure, then the vane projection is stable, but the oil flow becomes restricted causing excessive back-pressure rise
Solution Approach 1:
The communication portion's sectional surface area is designed to dynamically change during rotor rotation. It remains small during the compression process to maintain stable back-pressure for vane projection, then enlarges during the discharge process to facilitate oil flow and prevent excessive back-pressure rise.
Solution Approach 2:
The communication portion periodically changes its state between restricted (during compression) and enlarged (during discharge) as the rotor rotates, creating a cyclic pattern that optimizes both back-pressure maintenance and oil flow prevention.
3Reliability
If the vane groove bottom portion is separated from the drain groove to confine oil and increase back-pressure, then chattering is prevented, but the abrasion due to strong rubbing increases
Solution Approach 1:
The invention segments the operational cycle into compression phase (where separation occurs to prevent chattering) and discharge phase (where communication is restored to reduce abrasion). This temporal segmentation allows both benefits to be achieved at different times.
Solution Approach 2:
The communication portion is preliminarily enlarged before the discharge process begins, preparing the path for oil flow in advance. This preliminary action ensures that when the vane needs to retract, sufficient oil can flow to maintain appropriate back-pressure and prevent excessive rubbing.
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 prevents chattering and reduces abrasion by controlling back-pressure, ensuring efficient operation and minimizing power loss in the compressor.
Implementation Method 1
each of the plurality of plate-like vanes having a leading end portion formed to abut on the inner circumferential surface of the cylinder through a back-pressure from the vane groove
Implementation Method 2
the oil which is supplied to the vane groove from the discharge room through the oil path and the drain groove has a medium pressure which is lower than the discharge pressure of the air inside the discharge room because of the pressure drop caused by the fact that it passes through a narrow clearance formed between a shaft and the outer circumferential surface of the rotational axis
Implementation Method 3
the pressure inside the compression room exceeds the centrifugal force due to the back-pressure at medium pressure and the rotation of the vane
Data Source
AI summary
A gas compressor comprising a compressor main body including an approximately cylindrical rotor, a cylinder, a plurality of plate-like vanes formed to abut on the inner circumferential surface of the cylinder, and two side blocks is disclosed. A plurality of compression rooms is arranged inside the compressor main body so as to compress a medium and discharge the compressed high-pressure medium. A back-pressure-supplying groove supplies the back-pressure so as to project the vane toward the inner circumferential surface of the cylinder is arranged. An outer circumferential edge portion of the back-pressure-supplying groove is formed so as to increase a distance from a rotational center of the rotor toward the front side in the rotational direction of the rotor. A sectional surface area of a communication portion between the vane groove and the back-pressure-supplying groove increases until they are separated according to the rotation of the rotor.