Screw Compressor Axial Seal Grooves for Gas Leakage Reduction
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Solution Overview
Problem
Screw compressors face significant internal gas leaks due to axial fluid communication paths, which are not effectively addressed by existing technologies, leading to energy loss and reduced performance, even when supplied with liquids like oil.
Innovation Solution
The implementation of a screw compressor design featuring a casing with a shield area and grooves that inhibit the axial fluid communication path by creating a high-pressure oil film, reducing leaks through the axial fluid communication path by utilizing shear forces to pressurize the oil and form a static pressure buildup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a labyrinth of grooves is provided on the delivery end wall to seal the delivery-end-face clearance, then the internal leak through the delivery-end-face clearance is reduced, but the internal leak through the axial fluid communication path remains significant
Solution Approach 1:
The invention divides the sealing function into multiple segments: the labyrinth grooves handle the delivery-end-face clearance sealing, while the axial seal structure handles the axial fluid communication path sealing. This segmentation allows each structure to optimize for its specific sealing function without compromising the other.
Solution Approach 2:
The invention introduces an intermediary sealing structure (axial seal) specifically for the axial fluid communication path, which acts as a mediator to block the harmful fluid communication between suction and delivery sides without interfering with the normal compression function.
2Ease of operation
If the axial fluid communication path is left open to allow rotor rotation, then the rotors can rotate freely, but compressed gas leaks from high-pressure delivery space to low-pressure suction space
Solution Approach 1:
The invention extracts the harmful fluid communication function from the axial fluid communication path by introducing a separate axial seal structure. This allows the rotors to rotate freely while removing the harmful gas leakage path through the axial seal that blocks the communication between high-pressure and low-pressure sides.
Solution Approach 2:
The axial seal utilizes a thin film or flexible sealing structure that can accommodate rotor rotation while maintaining the seal. This flexible sealing mechanism allows the rotors to rotate freely without compromising the seal effectiveness against gas leakage.
3Force
If liquid is supplied to the working chamber to reduce friction, then the friction between rotors is reduced, but the axial fluid communication path still allows significant gas leakage
Solution Approach 1:
The axial seal acts as an intermediary structure that specifically addresses the gas leakage problem through the axial fluid communication path, independent of the liquid lubrication system. This allows the liquid to continue providing friction reduction while the axial seal handles the sealing function.
Solution Approach 2:
The invention segments the sealing function from the lubrication function: liquid supply handles friction reduction, while the axial seal structure handles gas leakage prevention. This segmentation allows both functions to operate independently and optimize for their specific purposes without interfering with each other.
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 design significantly reduces internal gas leaks via the axial fluid communication path, enhancing the compression and energy-saving performance of the screw compressor by maintaining a high-pressure oil film that prevents gas from leaking from high-pressure to low-pressure spaces.
Implementation Method 1
utilizing shear forces to pressurize the oil and form a static pressure buildup
Data Source
AI summary
A casing of a screw compressor has a delivery inner wall face facing delivery end faces of a male rotor and a female rotor. The delivery inner wall face of the casing has a shield area that shields at least a part of a track of an axial fluid communication path, which is a clearance that periodically occurs at the delivery end faces according to variation of intermeshing of the male and female rotors upon rotation thereof and is bounded by trailing flanks of the male and female rotors. The shield area of the casing is provided with a groove group made up of a plurality of grooves having longitudinal directions. The grooves of the groove group are juxtaposed in the circumferential direction of at least one rotor of the male and female rotors and are arranged such that their sides extending in the longitudinal directions are disposed adjacent to each other. Each groove of the groove group is configured such that its longitudinal direction oriented from the inner circumferential side of the one rotor toward the outer circumferential side is inclined with respect to the radial direction of the one rotor in the same direction as the rotational direction of the one rotor.