Pressure Regulating Valve Fail-Safe Design via Area Conversion
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Solution Overview
Problem
Existing pressure control valves in hydraulic systems lack fail-safe behavior, particularly when the actuation device fails, which can lead to unintended system operation or loss of function.
Innovation Solution
A pressure control valve design incorporating a pressure relief stage with an area conversion device that utilizes media pressure to ensure a fail-safe switching position, where the valve element is actuated by a pilot stage and a surface step-up device, allowing it to maintain a predeterminable position even without energized actuation, using existing components to achieve cost-effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a pressure control valve is designed with an energizable actuating device for controlling valve position, then the valve can be actuated precisely and controlled remotely, but the valve lacks fail-safe behavior when the actuation device fails
Solution Approach 1:
The patent applies preliminary anti-action by designing the pressure relief stage to automatically counteract any failure of the energizable actuating device. The area conversion device creates a pressure differential that generates a restoring force on the pilot piston, which acts in opposition to the actuating force. This preliminary design ensures that if the actuating device fails (e.g., loses power), the pressure differential automatically drives the pilot piston to a fail-safe position, closing the main valve and preventing unintended operation. The system is pre-configured with this counteracting mechanism rather than requiring active control.
Solution Approach 2:
The patent introduces an intermediary mechanism - the pressure relief stage with area conversion device - that mediates between the pilot stage and the main control stage. This intermediary translates the pilot piston position into a pressure differential across the main valve element, providing a buffer zone that ensures fail-safe behavior. The area conversion device acts as a mechanical translator that converts small pilot stage movements into significant pressure changes, ensuring reliable fail-safe operation even when the actuating device fails.
2Reliability
If a pressure relief stage with area conversion device is added to achieve fail-safe behavior, then the valve gains reliability, but the device complexity increases
Solution Approach 1:
The patent merges the pressure relief function with the pilot control stage by integrating the area conversion device directly into the pilot stage housing. The first and second pressure-effective areas are formed by diameter steps on the pilot piston itself, eliminating the need for separate relief valves or additional components. The outflow channel is integrated into the pilot stage housing, and the area conversion device shares the same pressure medium as the pilot control stage. This merging approach achieves fail-safe behavior while minimizing the increase in device complexity.
Solution Approach 2:
The pilot piston serves multiple functions: it responds to the actuating device for normal control operation, it acts as part of the area conversion device for fail-safe operation, and it controls the pressure differential across the main valve element. The pressure relief stage is designed to work during both normal operation and failure conditions, providing universal functionality. The same pressure medium serves both the pilot control stage and the area conversion device, further reducing the need for additional components.
3Device complexity
If the area conversion device uses diameter steps on the pilot piston to create pressure differential, then the design remains compact and cost-effective, but the manufacturing precision requirements increase
Solution Approach 1:
The patent changes the geometric parameters of the pilot piston by incorporating diameter steps at specific locations. These diameter steps create the first and second pressure-effective areas with different surface areas. By carefully selecting the diameters and axial positions of these steps, the design achieves the required area ratio for fail-safe operation. The parameter changes are implemented within standard manufacturing tolerances for piston machining, avoiding the need for exotic manufacturing processes while still achieving the precise area relationships needed for reliable fail-safe behavior.
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
The valve achieves a fail-safe function solely through media pressure, ensuring the valve element adopts a definable position, maintaining system functionality even if the actuation device fails, and allows for pressure-limiting or pressure-regulating operations with a compact and cost-effective design.
Implementation Method 1
A first, larger, pressure-effective area F1 and, compared thereto, a second, smaller, pressure-effective area F2 are formed on the pilot stage (7) which are acted upon by a medium pressure pv influenced by the pilot stage (7)
Implementation Method 2
The area conversion device (15) has a first, larger, pressure-effective area F1 and, in comparison, a second, smaller, pressure-effective area F2. A medium pressure pv influenced by the pilot stage (7) acts on both pressure-effective surfaces F1, F2
Implementation Method 3
The pilot control stage (7) is activated by means of an actuation device (9) that can be energized against the action of a restoring device (11)
Implementation Method 4
counter to the action of a restoring device (11)
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a valve (1), in particular a pressure regulating valve or a pressure limiting valve for controlling a pressure of a medium (3) that flows through the valve (1), comprising a main stage (5) and a pilot stage (7) which actuates the main stage (5), which is actuated against the effect of a restoring device (11) by means of an energizable actuating device (9), and which has a pressure release stage (13) of the valve (1). The pressure release stage (13) has a surface area modification device (15).