Ring Gate Two-Phase Closure for Hydraulic Machines
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Solution Overview
Problem
Conventional ring gates for hydraulic machines experience high vibrations and axial forces during emergency closure, leading to costly actuator design requirements, due to their non-linear flow characteristics, which complicate control and increase the risk of pressure surges.
Innovation Solution
The introduction of a second hollow-cylindrical body with strategically positioned openings that throttles the water flow during the closing process, allowing for a two-phase closure with different speeds, reducing the non-linearity and minimizing pressure surges by gradually interrupting the flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If a conventional ring gate is closed quickly to minimize vibration time, then the duration of vibration is reduced, but high pressure surges are generated
Solution Approach 1:
The closing process is segmented into two distinct phases: a first closing phase where the ring gate moves to partially close the passage, and a second closing phase where it completes the closure. This segmentation allows the first phase to occur at higher speed (reducing vibration duration) while the second phase controls the final closure at lower speed (minimizing pressure surge), thereby resolving the contradiction between fast closing and pressure surge prevention
Solution Approach 2:
The closing speed of the ring gate is made dynamic rather than constant. The control system adjusts the closing speed based on the phase of closure: faster speed during the first phase and slower speed during the second phase. This dynamic adjustment allows optimization of both vibration duration and pressure surge, resolving the technical contradiction
2Stress or pressure
If the closing speed is reduced to prevent pressure surges, then pressure surge risk is minimized, but the time spent in high vibration increases
Solution Approach 1:
The closure operation is divided into two phases with different speed characteristics. The first phase uses higher closing speed to quickly reduce the passage area and minimize vibration duration, while the second phase uses lower speed to gently complete the closure and minimize pressure surge. This segmentation resolves the contradiction by allowing each phase to optimize for its primary objective
Solution Approach 2:
The closing process implements periodic action with two distinct stages: a faster first stage for initial closure and a slower second stage for final closure. This periodic variation in closing speed allows the system to achieve both short vibration duration and low pressure surge by alternating between different operational modes
3Reliability
If actuators are designed to overcome high axial forces during closure, then the closure function is ensured, but actuator cost increases
Solution Approach 1:
The closure process is segmented into two phases with different force requirements. By controlling the gate to move faster in the first phase and slower in the second phase, the peak axial forces are reduced compared to a single-phase closure. This allows actuators to be designed with lower force capacity, reducing actuator cost while ensuring reliable closure function
Solution Approach 2:
The closing speed parameter is changed during the closure process, transitioning from high speed in the first phase to low speed in the second phase. This parameter change reduces the peak axial forces that actuators must overcome, allowing for less expensive actuator design while maintaining reliable closure functionality
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 linearizes the closing characteristics, reduces vibrations, and lowers the risk of pressure surges, allowing for a more efficient and cost-effective closure process by distributing the closing process across two bodies with optimized opening sizes and distributions.
Implementation Method 1
Body 2 has a smaller diameter than body 1, allowing it to be pushed inside body 1... body 2 is designed so that it cannot completely interrupt the water flow. This is achieved by openings in the wall of body 2 through which water flows when body 2 is in the lowered position. These openings are not shown in the figures. In this way, body 2 acts as a throttle in its lowered position
Data Source
Figure 1~2
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Figure 5
AI summary
The invention relates to a ring gate for interrupting the water flow through the water path of a hydraulic machine having a rotor and having a spiral, comprising a first hollow body (1), which extends around the rotor axis and which is designed in such a way that said first body can be moved from an open position to a closed position and back, wherein no water flow through the hydraulic machine can occur when the first body (1) is in the closed position, wherein the ring gate comprises a second hollow body, which extends around the rotor axis and which is designed in such a way that said second body can be moved from a first position outside of the water path to a second position within the water path and back in the axial direction, wherein the second body (2) has openings in the wall of the second body, through which openings water can flow when the second body (2) is in the second position and the first body (1) is not in the closed position.