Hydraulic Valve Actuator Speed Feedback Under Temperature Variation
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Solution Overview
Problem
Hydraulically operated drive units in valves face challenges with varying ambient temperatures, leading to inconsistent operating times due to changes in hydraulic fluid viscosity, resulting in inadequate valve movement at low temperatures and excessive movement at high temperatures, potentially causing pressure surges.
Innovation Solution
A method to control the actuating speed of the drive unit by determining the speed over part of the actuating path and comparing it to a predetermined target speed, adjusting the control to maintain consistent positioning times through sensors or indirect measurements, such as distance and time, and adjusting pressure to achieve the specified positioning time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the valve is operated at low temperatures with high viscosity hydraulic fluid, then the valve can be moved or adjusted, but the movement is too slow to meet response time requirements
Solution Approach 1:
The control system dynamically adjusts the hydraulic pressure based on measured piston speed. When the piston moves slower than the target speed (as occurs at low temperatures), the control system increases the pressure differential across the piston to accelerate movement. This dynamic adjustment ensures the valve reaches its target position within the required time regardless of temperature conditions.
Solution Approach 2:
The system continuously measures the actual piston speed using position sensors and compares it to a target speed profile. Based on this feedback, the control system adjusts the hydraulic pressure in real-time to correct deviations from the target speed, ensuring consistent response times across varying temperature conditions.
2Speed
If the valve is operated at high temperatures with low viscosity hydraulic fluid, then the valve moves quickly, but pressure surges occur causing water hammer effects
Solution Approach 1:
The control system dynamically reduces hydraulic pressure when the piston speed exceeds the target speed (as occurs at high temperatures). This prevents excessive movement speed that would cause pressure surges and water hammer effects, while still allowing the valve to move quickly enough to meet response time requirements.
Solution Approach 2:
The control system uses feedback from position sensors to detect when the piston is moving faster than the target speed and adjusts the hydraulic pressure accordingly to reduce speed and prevent pressure surges, eliminating water hammer effects while maintaining adequate response time.
3Loss of time
If the hydraulic pressure is increased to speed up valve movement at low temperatures, then the response time improves, but energy consumption increases and system stress rises
Solution Approach 1:
The control system applies hydraulic pressure dynamically based on actual piston speed measurements. Pressure is increased only when and where needed to maintain target speed, rather than applying maximum pressure throughout the entire stroke. This minimizes energy consumption while ensuring the valve meets response time requirements.
Solution Approach 2:
The system changes the hydraulic pressure parameter dynamically based on measured piston speed and temperature conditions. By adjusting pressure to match actual operating conditions rather than using fixed high pressure, the system reduces energy consumption while maintaining adequate response time.
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 approach ensures consistent operating times for valve adjustments regardless of ambient temperature, providing precise control even in extreme conditions by directly measuring actuation time and adjusting pressure, thus mitigating the influence of viscosity on operating times.
Implementation Method 1
a hydraulically actuated drive unit (1) for a valve (2), wherein on one side of the piston (1) is acted upon by a spring (3) and, on the other side, by the pressure of a hydraulic fluid
Implementation Method 2
on one side of the piston (1) is acted upon by a spring (3) and, on the other side, by the pressure of a hydraulic fluid
Implementation Method 3
the actuating speed is determined via suitable sensors or indirectly, in particular by measuring distance and time
Implementation Method 4
the control of the actuator is corrected so that the actuator completes the travel path within the predetermined travel time
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a method for controlling a hydraulically actuated drive unit (1-3) in particular for a valve, wherein the adjustment velocity (v1) is determined at least over part of the adjustment travel of the drive unit and is compared with a specified target adjustment velocity (v), whereupon, in the case of a difference between the actual value (v1) and the target value (v) of the velocity, the control of the drive unit (1-3) is changed in such a way that the adjustment velocity (v') of the drive unit is adjusted to the target value (v).