Valve assembly for connecting a heat exchanger of a hot water discharging device to a district heating system
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Solution Overview
Problem
The production of valve arrangements for connecting heat exchangers to district heating networks is expensive due to the need for precise matching of primary and secondary side valves, requiring small manufacturing tolerances to ensure proper heat transfer and service water temperature control.
Innovation Solution
A valve arrangement where the secondary-side valve has a membrane with an adjustable cone-shaped valve element, allowing for post-manufacture adjustment of the quiescent opening size, and a temperature-controlled primary-side valve actuated by a plunger driven by the secondary-side valve, enabling independent control and reducing manufacturing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the primary-side valve and secondary-side valve are precisely matched during manufacture, then temperature control precision is improved, but manufacturing cost increases and manufacturing precision requirements become more stringent
Solution Approach 1:
The valve system is segmented into independent primary-side and secondary-side valves that are not precisely matched during manufacture. The secondary-side valve independently controls service water flow while the primary-side valve controls heat transfer fluid flow, eliminating the need for precise coordination between the two valves during manufacturing.
Solution Approach 2:
The secondary-side valve independently regulates service water flow and temperature without requiring precise matching with the primary-side valve. The system allows each valve to function autonomously, with the secondary-side valve self-adjusting to provide the desired service water temperature regardless of the primary-side valve state.
2Manufacturing precision
If small manufacturing tolerances are maintained, then valve matching precision is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The valve arrangement separates the control functions into independent primary-side and secondary-side valves that do not require precise matching. This segmentation allows each valve to be manufactured with standard tolerances without affecting overall system performance.
Solution Approach 2:
The system changes the operational parameters by allowing the secondary-side valve to independently control service water flow and temperature. This parameter change eliminates the need for precise valve matching, as the secondary-side valve can adjust its opening degree to achieve the desired temperature regardless of the primary-side valve characteristics.
3Speed
If the quiescent opening is made very small, then response speed of the primary-side valve is improved, but manufacturing precision requirements increase
Solution Approach 1:
The secondary-side valve independently controls service water flow without requiring precise quiescent opening settings. The valve can open to any degree needed to provide the desired service water temperature and flow rate, eliminating the need for precise factory adjustment of the rest opening position.
Solution Approach 2:
The system allows the secondary-side valve to dynamically adjust its opening degree based on actual service water demand and temperature requirements. Rather than relying on a precisely set small quiescent opening, the valve can open to whatever extent is necessary to meet the thermal load, improving responsiveness without increasing manufacturing precision requirements.
4Reliability
If the secondary-side valve is fully closed at rest, then sealing is improved, but clogging risk at low flow rates increases
Solution Approach 1:
The secondary-side valve maintains a dynamically adjustable opening that can remain slightly open even at rest, allowing continuous minimal flow through the heat exchanger. This prevents stagnation and reduces clogging risk while the valve can close sufficiently to provide adequate sealing when service water is not being drawn.
Solution Approach 2:
The system maintains continuous flow through the heat exchanger by keeping the secondary-side valve slightly open at rest, ensuring that water continuously circulates and preventing sediment accumulation and clogging. This continuous action maintains both sealing performance and flow characteristics.
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 design simplifies manufacturing by allowing for reduced accuracy in part production, reduces the risk of clogging at low flow rates, and ensures precise temperature control of service water, while maintaining efficient heat transfer and valve responsiveness.
Implementation Method 1
If the pressure conditions across the membrane change, then the membrane is moved and then shifts the valve seat relative to the valve element
Implementation Method 2
a heat exchanger (1), shown schematically, with a primary side (2) and a secondary side (3)... a heat exchanger surface (12) arranged between the primary side (2) and the secondary side (3)
Data Source
Figure 1
Figure 2
AI summary
Disclosed is a valve assembly (6) for connecting a heat exchanger (1) of a hot water discharging device to a district heating system. Said valve assembly (6) comprises a valve (20) which is located on a primary side and controls a flow of heat exchange fluid through a primary side (2) of the heat exchanger (1), and a pressure-controlled valve (40) that is located on a secondary side and acts upon a flow of process water through a secondary side (3) of the heat exchanger (1). The valve (20) located on the primary side can be actuated by the valve (40) located on the secondary side. In order to simplify the production of such a valve assembly, the valve (40) that is located on the secondary side is provided with an adjustable neutral opening (44).