Hydraulic Striking Device Cavitation Prevention
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Solution Overview
Problem
Hydraulically striking devices in rock drilling applications face issues with cavitation due to inadequate hydraulic fluid circulation, leading to wear and malfunction, particularly when air is trapped in the system and fluid temperature increases, causing rapid air bubble explosions that damage components.
Innovation Solution
The design incorporates a hydraulically striking device with a cylinder and piston system featuring controlled flow channels and ports that ensure hydraulic fluid circulation in one direction, using a spool or poppet mechanism to direct fluid flow, and includes a choke in the return line to prevent cavitation by creating back pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the hydraulic fluid is used to control the piston reciprocating movement, then the piston can be controlled to move between first and second positions, but the hydraulic fluid does not change completely and creates cavitation that damages the device
Solution Approach 1:
The control channel is divided into a first control channel and a second control channel, with the piston containing a first flow space and a second flow space. This segmentation allows the hydraulic fluid to be divided into two separate flow paths, enabling complete fluid change and circulation while maintaining piston control functionality.
Solution Approach 2:
The piston itself acts as an intermediary element that separates the hydraulic fluid flow into two distinct channels. By incorporating flow spaces within the piston structure, the system enables complete fluid displacement and circulation, preventing cavitation while maintaining operational control.
2Ease of operation
If the hydraulic fluid circulates back and forth between the piston and controlling arrangement, then the piston can be controlled, but the fluid creates cavitation and air bubbles explode rapidly damaging components
Solution Approach 1:
The control channel is segmented into separate first and second control channels with corresponding flow spaces in the piston. This segmentation ensures that hydraulic fluid flows in a controlled manner through distinct paths, preventing the back-and-forth circulation that causes cavitation and air bubble explosions.
Solution Approach 2:
The system converts the potential harm of fluid circulation into a beneficial complete fluid change mechanism. By designing the flow spaces and control channels to enable complete fluid displacement, the system transforms what would normally cause cavitation into a protective circulation pattern that prevents air bubble formation and cavitation damage.
3Productivity
If the hydraulic fluid temperature increases, then the fluid becomes more likely to cavitate, but the system continues to operate
Solution Approach 1:
The hydraulic fluid circulation system is segmented into separate control channels and flow spaces that enable complete fluid change. This segmentation ensures that even at elevated temperatures, the fluid is continuously replaced and circulated effectively, preventing the temperature-related cavitation that would otherwise occur during continuous operation.
4Productivity
If air is trapped in the hydraulic circuit, then the air mixes with hydraulic fluid and leads to easier cavitation, but the system operates without complete air removal
Solution Approach 1:
The control channel segmentation into first and second channels with corresponding flow spaces creates a circulation pattern that actively works to remove trapped air. The separated flow paths enable complete fluid displacement, which prevents air pockets from forming and eliminates the conditions for cavitation even when air is initially present in the system.
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 enhances fluid circulation, reduces the risk of cavitation, prevents wear on components, and ensures efficient operation by maintaining fluid flow in one direction, effectively addressing the issues of trapped air and temperature-related cavitation.
Implementation Method 1
allowing the hydraulic fluid which controls the valve in the first control channel and in the second control channel to flow in one direction so as to provide circulation of the hydraulic fluid controlling the valve
Implementation Method 2
includes a choke in the return line to prevent cavitation by creating back pressure
Implementation Method 3
using a spool or poppet mechanism to direct fluid flow
Data Source
Figure 1a~1b
Figure 2a~2b
Figure 3a~3b
AI summary
A hydraulically striking device comprising a cylinder body, the cylinder body forming a cylinder therein, a piston in the cylinder body, configured to move by means of a hydraulic fluid so as to reciprocate between a first and a second position in the cylinder. According to the invention, a first control channel and a second control channel extend from the valve, a first port and a second port open into the cylinder, wherein the first port is coupled to the first control channel and the second port is coupled to the second control channel, the piston comprising at least one flow space which is arranged to be selectively coupled to the first port and to the second port and allowing the hydraulic fluid to flow in one of the control channels in one direction so as to provide circulation of the hydraulic fluid controlling the valve.