Hydraulic Percussive Arrangement Bushing Erosion Mitigation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In hydraulic percussive drilling machines, the pressure difference between high-pressure and low-pressure chambers causes hydraulic oil to flow rapidly along the surface of the piston, leading to erosion and leakage of bushings, which shortens their lifespan and can result in complete failure.
Innovation Solution
A third chamber is introduced in the piston guide, with a larger passage connecting it to the first chamber, allowing hydraulic oil to flow freely and reducing the pressure gradient, thereby minimizing the impact of high-speed oil on the bushings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydraulic oil is drained from the first chamber to the return line, then the pressure on the bushing is reduced, but the pressure difference forces hydraulic oil to flow at high speed along the piston surface, causing erosion and leakage
Solution Approach 1:
A third chamber is introduced as an intermediary between the high-pressure second chamber and the low-pressure first chamber. This intermediate chamber allows hydraulic oil to flow through a controlled path with a larger passage, reducing the pressure gradient and flow velocity that would otherwise directly impact the bushing, thereby protecting it from erosion while maintaining pressure differential functionality
Solution Approach 2:
The flow path is extended by adding a third chamber, transforming the direct one-dimensional flow from second to first chamber into a multi-chamber path. This dimensional extension allows for a larger passage area in the connection between chambers, reducing flow velocity and pressure gradient while maintaining the necessary pressure differential for piston operation
2Power
If the pressure difference between chambers is maintained, then the piston can function properly, but the high-speed hydraulic oil flow causes the bushing ring to lift and leak
Solution Approach 1:
The third chamber serves as a mediator that decouples the pressure differential function from the direct high-velocity flow path. By routing oil through this intermediate chamber with a larger passage, the pressure gradient is reduced, preventing the bushing ring from lifting while maintaining sufficient pressure difference for piston operation
3Reliability
If two bushings are arranged in series, then sealing is improved, but pressure between the bushings causes the inner bushing to turn and the outer bushing to extrude, leading to complete failure
Solution Approach 1:
The third chamber acts as a pressure buffer between the high-pressure region and the bushing assembly. By providing an intermediate pressure zone with a larger passage connection, it reduces the pressure load on the bushings, preventing the inner bushing from turning onto its edge and the outer bushing from being extruded along the piston
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 solution reduces the load on the bushings, extending their operating life and preventing leakage, while maintaining a compact design that can withstand higher pressures.
Implementation Method 1
the pressure difference in the gap between the piston and the casing, which pressure difference is between the second chamber with its high pressure of hydraulic oil and the drained first chamber, will force hydraulic oil along the longitudinal direction of the gap
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The present invention relates to a hydraulic percussive arrangement comprising a displaceable arrangement (1) in a casing (11), in which casing (11) the following are arranged at the displaceable arrangement (1 ): a first chamber (5) connected to a return line (7) for hydraulic oil, a bushing (6) on a first side of the first chamber (5) and separated from the first chamber (5) by a first gap (12) along the displaceable arrangement (1), and a second chamber (2) with a higher pressure of hydraulic oil than that of the first chamber (5) and arranged on a second side of the first chamber (5), separated from the first chamber (5) by a second gap (4) along the displaceable arrangement (1). According to the invention, a third chamber (8) is fixed arranged between the second gap (4) and the first chamber (5) and the third chamber (8) is connected to the first chamber (5) not only by a first passage (14) but also by a third gap (9) along the displaceable arrangement (1). The invention relates also to a piston guide in such a hydraulic percussive arrangement and to a drilling rig with such a percussive arrangement.