Compressor Piston Ring Grooves for Balanced Differential Pressure
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Solution Overview
Problem
In reciprocating compressors, the differential pressure applied to piston rings varies over time, leading to uneven wear and reduced lifespan due to changes in joint clearances and sliding motion, which complicates maintaining equal differential pressure across the rings.
Innovation Solution
A piston design with leakage grooves on the low-pressure side of ring grooves allows gas to leak from high-pressure to low-pressure sides, reducing differential pressure and minimizing wear by adjusting the number and flow area of leakage grooves based on differential pressure magnitude across piston rings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sealing property of piston rings is increased to prevent gas leakage, then a large differential pressure is applied to some piston rings, but this shortens the life of the piston rings
Solution Approach 1:
The patent introduces leakage grooves at specific locations (low-pressure side surfaces of ring grooves) to create localized pressure relief zones. This allows different regions of the piston ring system to have different pressure characteristics - the sealing surfaces maintain high sealing property while the leakage grooves reduce differential pressure on specific rings, thereby extending their service life.
2Duration of action of moving object
If the size of joint clearances is adjusted to equalize differential pressure, then progress of local abrasion is suppressed, but abrasion progresses with passage of time due to reciprocating motion, changing the joint clearance size
Solution Approach 1:
The patent extracts the pressure equalization function from the joint clearance design and relocates it to dedicated leakage grooves. By providing separate pressure relief pathways through the leakage grooves, the system maintains stable joint clearances while achieving differential pressure equalization, preventing the instability that occurs when clearance size changes due to wear.
3Stress or pressure
If leakage grooves are formed on the low-pressure side surface of ring grooves, then differential pressure is reduced and eased between piston rings, but the leakage groove may be influenced by sliding motion
Solution Approach 1:
The patent positions the leakage grooves on the low-pressure side surfaces of ring grooves, which serve as intermediary zones between the high-pressure compression chamber and the low-pressure crankcase. This location allows the grooves to effectively mediate pressure equalization while being protected from direct sliding contact, as they are situated in the groove structure rather than on the outer peripheral surface of the piston rings.
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 maintains a balanced differential pressure across piston rings, reducing wear and extending their lifespan by dispersing pressure and minimizing the impact of sliding motion on leakage grooves, thus maintaining performance over time.
Implementation Method 1
a gas is leaked out from the space on the high-pressure side to the space on the low-pressure side through the leakage groove
Data Source
AI summary
In a piston including a plurality of piston rings, a state where a difference in differential pressure between the piston rings is eased is maintained even after passage of time, and the life of the piston rings is extended. A piston includes a piston body in which a plurality of ring grooves is formed, and a plurality of piston rings respectively arranged in the ring grooves. In the piston, a leakage groove is formed on a low-pressure side surface of the ring groove, and in a state where the piston ring is abutted with the low-pressure side surface while being abutted with a cylinder, the leakage groove ensures communication between a high-pressure side space and a low-pressure side space with respect to the piston ring.