Hydraulic Emergency-Stop Valve Layout to Prevent Load-Induced Movement
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Solution Overview
Problem
Existing hydraulic control devices with emergency stop functions can lead to unwanted movements at hydraulic consumers during load conditions, posing safety risks due to the parallel arrangement of pilot pressure generation, which does not effectively prevent energy flow from working ports to the tank or return, especially in mobile machines.
Innovation Solution
Incorporating a 3/2-way diverter valve as part of the emergency-stop device allows for the simultaneous interruption of hydraulic energy flow from the pressure supply and pilot pressure to the control valve, enabling the system to function as an OR gate, thereby preventing unwanted movements by selectively decoupling hydraulic circuits and reducing power loss through optimized spring loading and filtration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a 2/2-way solenoid valve is used to control the separating valve for emergency stop, then the hydraulic energy flow from the pressure supply to the working ports can be interrupted, but the energy flow from the working ports to the tank or return cannot be effectively prevented, leading to unwanted movements at consumers
Solution Approach 1:
The patent inverts the control logic by using a 3/2-way valve that defaults to blocking the return path and only opens under specific pilot pressure conditions. This reversal ensures that the emergency stop function actively prevents unwanted movements by blocking the return flow path, rather than relying on passive interruption of the supply path as in conventional 2/2-way valve systems.
Solution Approach 2:
The patent introduces a pilot pressure control system as an intermediary mechanism. The pilot pressure, generated through a dedicated circuit with flow regulators and aperture devices, mediates the switching action of the 3/2-way valve. This intermediary control ensures that the emergency stop function reliably interrupts both supply and return energy flows by controlling the pilot pressure that actuates the main valve.
2Power
If pilot pressure generation is arranged in parallel to the emergency stop shutdown system, then sufficient pressure can always be generated for control valve actuation, but this arrangement cannot prevent energy flow from working ports to tank or return during emergency stop
Solution Approach 1:
The patent segments the hydraulic system into distinct functional circuits: a pilot pressure generation circuit and an emergency stop control circuit. The pilot pressure circuit is separated and arranged upstream of the 3/2-way valve, allowing it to maintain independent pressure generation capability while the emergency stop circuit controls the main energy flow paths. This segmentation enables both functions to operate independently and reliably.
Solution Approach 2:
The patent implements preliminary action by pre-arranging the pilot pressure generation circuit upstream of the 3/2-way valve. This ensures that pilot pressure is available in advance and can immediately actuate the control valve when needed, while the emergency stop function can independently interrupt the main energy flows. The flow regulators and aperture devices are pre-configured to ensure proper pressure distribution before emergency stop activation.
3Reliability
If a 3/2-way diverter valve is used as part of the emergency-stop device to simultaneously interrupt hydraulic energy flow and pilot pressure supply, then safety is enhanced and unwanted movements are prevented, but the device complexity increases
Solution Approach 1:
The patent applies multi-functionality by designing the 3/2-way diverter valve to perform multiple functions simultaneously: it acts as an emergency stop valve, a pilot pressure control valve, and an OR gate element in the hydraulic system. This single valve controls both the main hydraulic energy flow and the pilot pressure supply to the control valve, eliminating the need for separate valves for each function and thereby reducing overall system complexity despite the enhanced safety functionality.
Solution Approach 2:
The patent merges the emergency stop function and the pilot pressure control function into a single integrated 3/2-way diverter valve assembly. By combining these functions that were previously handled by separate components, the system achieves enhanced safety through simultaneous interruption of both energy flows while reducing the number of discrete parts and simplifying the control logic.
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 solution ensures enhanced safety by preventing unwanted movements during load conditions and reducing power loss by a factor of 3 to 4 compared to conventional systems, while maintaining the integrity of safety functions and reducing contamination risks.
Implementation Method 1
a pilot solenoid valve (16) can be used to stop both the hydraulic energy flow from the pressure supply source to at least one of the respective working sections and the pilot pressure supply to the control valve via another valve (14)
Implementation Method 2
By using a diverter valve, preferably in the form of a 3/2-way valve, as a further valve of the emergency-stop device
Data Source
AI summary
A control device for at least one hydraulic working section (A, B), which can be connected to a pressure supply source (P) and a return flow (T) via a hydraulic supply circuit and to a control valve (34) supplied with a pilot pressure. The device includes an emergency shutdown system (32) having a pilot solenoid valve (16) and an additional valve (14). Both the hydraulic energy flow from the pressure supply source (P) to at least one of the respective working sections (A, B) and the pilot pressure supply to the control valve (34) can be suppressed by the pilot solenoid valve (16) via the additional valve (14).