Valve unit for controlling flow of heat transfer liquid and heating system
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Solution Overview
Problem
Central heating systems with disc valves face challenges in precise control and energy efficiency due to high energy consumption, poor controllability, and issues with impurity accumulation and sealing element degradation, making them unsuitable for electronic actuators.
Innovation Solution
A valve unit with a rotatable valve element and a stationary flow control surface, where the valve element adjusts the flow area by rotation, reducing energy consumption and eliminating impurity accumulation, and utilizing an electrical actuator that does not work against spring force, allowing for precise control and battery operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a disc valve with elastic sealing element is used, then the valve can be operated with unidirectional force from mechanical actuators, but the sealing element loses elastic properties over time and sticks to the valve seat, causing poor reliability
Solution Approach 1:
The patent removes the elastic sealing element from the valve structure. Instead of using a disc with rubber seal that degrades over time, the invention uses a needle valve element that seals through its geometry and contact pressure, eliminating the component subject to elastic property loss and sticking
Solution Approach 2:
The patent replaces the wear-prone elastic sealing element with a simple metal needle valve element that has no consumable sealing components. The needle valve seals through direct metal-to-metal contact and geometric fit, eliminating parts that need periodic replacement due to material degradation
2Ease of operation
If a disc valve with spring loading is used, then the valve can be operated with unidirectional force, but significant spring force (50 N) is required, leading to high energy consumption when used with electronic actuators
Solution Approach 1:
The patent replaces the spring-mechanical actuation system with a direct needle valve mechanism that requires minimal force to operate. The needle valve's linear motion in a tapered seat creates mechanical advantage, allowing small forces to achieve full valve control without energy-intensive springs or complex mechanical transmissions
Solution Approach 2:
Instead of using a spring to push the disc valve open against flow pressure, the needle valve design allows flow pressure itself to assist in valve operation. The tapered geometry converts flow pressure into opening force, inverting the traditional approach where external springs must overcome flow resistance
3Manufacturing precision
If a disc valve with short moving range is used, then the valve structure is compact, but precise control becomes very difficult due to the short control range close to fully closed position
Solution Approach 1:
The patent employs a needle valve element with extended linear travel capability. The needle can move through a large range from fully closed to fully open positions, providing fine control resolution throughout the entire range. This dynamic linear motion allows precise positioning at any opening degree, unlike disc valves constrained to short rotational movements
4Adaptability or versatility
If a disc valve allows water flow between sealing surfaces when not completely closed, then the valve can be partially open for flow control, but impurities in water adhere to sealing surfaces, causing sticking and affecting flow area
Solution Approach 1:
The patent eliminates the broad sealing surfaces between the disc and valve seat that trap impurities. The needle valve uses a narrow, precisely-machined tapered contact surface that minimizes area for impurity accumulation. The sealing mechanism relies on line contact rather than face contact, reducing the harmful effect of particulate matter in the fluid
Solution Approach 2:
Instead of having sealing surfaces that face each other parallel to flow direction (where impurities accumulate), the needle valve uses a tapered geometry where the sealing surface is angled relative to flow. This inversion of the sealing geometry allows impurities to be swept away by flow rather than trapped against the sealing interface
Data Source
Figure 1~2B
Figure 3
Figure 4
AI summary
The valve unit (1) for controlling the flow of a heat transfer liquid through a heating element (33) of a central heating system comprises a valve (2) and an electrical actuator (15) for operating the valve (2), the valve comprising a flow channel (4) having an inlet (4a) and an outlet (4b), a stationary flow control surface (5) arranged between the inlet (4a) and the outlet (4b) and comprising at least one control surface opening (6) for the flow of the heat transfer liquid, and a rotatable valve element (7) for controlling the flow in the flow channel (4), the valve element (7) comprising at least one valve element opening (8), the valve element (7) being rotatable against the flow control surface (5) about an axis that is perpendicular to the flow control surface (5), wherein by rotation of the valve element (7) the position of the valve element opening (8) relative to the control surface opening (6) can be changed to adjust the size of the overlapping areas of the valve element opening (8) and the control surface opening (6).