Passive Fill Level Control via Vertical Heat Exchanger
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Solution Overview
Problem
Existing passive level control systems in nuclear power plants, such as those used in steam generators, are structurally complex, require auxiliary systems like compressed air, and exhibit abrupt switching behavior, leading to undesired loads and reduced passivity.
Innovation Solution
A passive level control system featuring a vertically aligned heat exchanger with a continuously adjustable pilot valve, allowing for adaptive control of the fill level by varying the flow through the feed line based on the liquid phase's level, eliminating the need for auxiliary energy and reducing structural complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a passive pressure pulse transmitter (PPPT) is used for level monitoring, then level control is achieved without active components, but the system requires two pulse generators with associated cables and connections, increasing structural complexity
Solution Approach 1:
The patent combines the heat exchanger and level control functions into a single integrated component. The heat exchanger serves dual purposes: thermal exchange and level control through its connection to the standpipe, eliminating the need for separate pulse generators and reducing structural complexity while maintaining passive operation
Solution Approach 2:
The heat exchanger is designed to perform multiple functions simultaneously: it acts as a thermal exchange device and as a level control mechanism through its integration with the standpipe. This multi-functionality reduces the number of separate components needed in the system
2Extent of automation
If a PPPT is used for level monitoring, then passive operation is achieved, but auxiliary systems like compressed air are required to open valves, reducing passivity and increasing dependency
Solution Approach 1:
The system uses the natural thermal dynamics between the primary and secondary media to automatically control the valve. The heat exchanger self-regulates the fill level by utilizing temperature differences and phase changes, eliminating the need for external compressed air systems or other auxiliary energy sources
3Measurement precision
If a PPPT is used for level monitoring, then level limits are detected, but abrupt switching behavior occurs, leading to undesirable stress on the system
Solution Approach 1:
The control valve is designed with dynamic characteristics that allow for gradual opening and closing based on the thermal state. The heat exchanger's thermal mass and the phase change process provide inherent damping, transforming abrupt switching into smoother, more gradual valve movements that reduce mechanical stress
4Ease of operation
If conventional active control systems are used for level control, then precise control is achieved, but level sensors, electrical cables, process computers and power supply are required, increasing structural complexity
Solution Approach 1:
The patent replaces electronic sensing and control systems with a purely thermal-mechanical system. The heat exchanger uses temperature differences and phase changes to directly actuate the control valve, eliminating the need for level sensors, electrical cables, computers, and power supplies while maintaining control precision
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 system provides reliable, responsive, and needs-based fill level control with reduced structural complexity, avoiding undesired jumps and oscillations, and operates independently without auxiliary energy, ensuring compact installation and efficient operation.
Implementation Method 1
the standpipe in a subsection forms the primary side of a heat exchanger, the secondary side of which has a secondary line receiving a secondary medium
Implementation Method 2
the primary medium has a liquid phase and a vapor phase in the container during operation
Data Source
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AI summary
The invention relates to a passive fill state regulating system comprising the following - a container (4) which receives a primary medium (P), said primary medium (P) having a liquid phase (6) and a steam phase (8) in the container (4) during operation, - a primary medium (P) supply line (10) which is connected to the container (4) and into which a regulating valve (14) is connected, and - a standpipe (18, 18') which is connected to the container (4) as communicating pipes and through which the primary medium (P) flows. A part of the standpipe (18, 18') forms the primary side of a heat exchanger (20), the secondary side of which has a secondary line (30) that receives a secondary medium (S), wherein a pilot valve (16) which acts on the regulating valve (14) is connected into the secondary line. The invention is characterized in that the heat exchanger (20) has an elongated heat exchanger surface (32) which is largely vertically aligned, and the pilot valve (16) and the regulating valve (14) can be adjusted continuously such that the flow through the supply line (10) continuously varies with the fill state of the liquid phase (6) in the container (4).