Hydraulic Shut-Off Valve with Pressure-Limited Blocking Device
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Solution Overview
Problem
Shut-off valves in hydraulic systems, particularly in agricultural machines, experience sudden pressure equalization and jerky movements due to high pressure differences when closing, making controlled opening difficult and leading to abrupt pressure release with negative consequences.
Innovation Solution
A shut-off valve with a blocking device that limits the actuation of the valve slide to an intermediate position based on pressure differences, allowing controlled pressure equalization and reducing dynamics, lifting the blockage only when the pressure difference falls below a predetermined value for smooth operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the shut-off valve is opened fully to reduce flow resistance, then the flow resistance decreases, but the pressure equalization occurs abruptly causing jerky movements and instability
Solution Approach 1:
The valve opening process is segmented into multiple stages: initially limited to an intermediate position by the blocking device, then gradually opened to full position. This segmentation prevents abrupt pressure equalization while maintaining acceptable flow resistance through controlled progression.
Solution Approach 2:
The blocking device dynamically adapts to pressure differences, automatically limiting the valve opening when pressure differential exceeds a threshold, and releasing the limitation when pressure equalizes. This dynamic control stabilizes the system during pressure transitions.
2Speed
If the valve slide is actuated quickly to open the valve, then the opening speed increases, but the high opening forces cause stick-slip effect and difficult control
Solution Approach 1:
The blocking device applies partial action by limiting the valve slide movement to an intermediate position during high pressure differential conditions. This partial opening reduces the required opening force while still allowing pressure equalization, making the valve easier to operate without requiring full-force actuation.
3Stability of the object's composition
If the blocking device limits the valve opening to intermediate position, then the pressure equalization is controlled and stability improves, but the flow resistance increases
Solution Approach 1:
The valve operation follows a periodic pattern: opened to intermediate position for controlled pressure equalization, then fully opened when pressure stabilizes. This periodic cycling between limited and full opening states maintains system stability while minimizing overall flow resistance through timely transitions.
Data Source
Figure 1
Figure 2a~2b
Figure 3a~3b
AI summary
A shut-off valve (18) for a hydraulic arrangement (12, 14, 15) is proposed. The shut-off valve (18) comprises an actuated valve spool (22) for setting a closed position and an open position. To ensure flow-controlled pressure equalization when the shut-off valve (18) is opened, it is proposed that a locking device (29) be provided to limit the actuation of the valve spool (22) to an intermediate position between the closed and open positions, in which the opening cross-section of the shut-off valve (18) is only a fraction of the opening cross-section present in the open position.The locking device (29) is designed such that the actuation of the valve slide (22) by the locking device (29) is limited depending on a pressure differential value between a pressure before and after the shut-off valve (18), whereby the limitation can be lifted if a predefinable pressure differential value is undershot.