Heating Air Inlet Check Valve Layout for Exhaust Backflow
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Solution Overview
Problem
Existing heating devices in multi-unit buildings face challenges in installing check valves to prevent exhaust gas backflow without exposing them to high temperatures or condensate, and existing solutions complicate the installation process and require adjustments that are prone to errors.
Innovation Solution
Install the check valve in the air supply upstream of the Venturi device and connect the gas valve's control line between the Venturi device and the check valve, allowing for easy installation and avoiding exposure to high temperatures or condensate, while maintaining optimal air-fuel ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the check valve is installed in the exhaust gas path, then it can prevent exhaust gas backflow, but it is exposed to high temperatures and condensate which reduces its service life
Solution Approach 1:
The check valve is extracted from the exhaust gas path and relocated to the combustion air supply line. This separates the check valve from the harmful high-temperature and condensate environment while maintaining its backflow prevention function for exhaust gases through system pressure differential
Solution Approach 2:
The combustion air supply line acts as an intermediary location for installing the check valve. This intermediate position allows the check valve to influence exhaust gas flow prevention without being directly exposed to the harsh exhaust gas environment
2Temperature
If the check valve is installed upstream of the venturi device in the air supply, then it avoids exposure to high temperatures and condensate, but it causes pressure drop that requires gas valve adjustment
Solution Approach 1:
The control line system automatically compensates for the pressure drop caused by the check valve. The system self-regulates by using the pressure differential created by the check valve to modulate the gas valve, eliminating the need for manual adjustments by installers
Solution Approach 2:
The control line creates a feedback mechanism where the pressure drop across the check valve is transmitted back to the gas valve, causing it to automatically adjust its opening degree to compensate for the pressure loss and maintain proper air-fuel ratio
3Ease of manufacture
If the check valve is installed in the air supply upstream of the venturi device, then it simplifies installation at the installation site, but it requires connecting the control line between the venturi device and the check valve
Solution Approach 1:
The control line connection is merged with the existing air supply line connections. The control line utilizes the same connection points and routing as the air supply, combining multiple functions into a single installation process and reducing the number of separate connection operations required
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 method simplifies the installation of check valves, prevents exhaust gas backflow, and maintains efficient operation by compensating for pressure drops without requiring complex adjustments, thus enhancing safety and efficiency.
Implementation Method 1
The check valve allows only unidirectional flow, thus preventing exhaust gases from entering the heating appliance and its surroundings
Implementation Method 2
A defined quantity of fuel gas can be added to this air supply via a gas valve and a Venturi device
Implementation Method 3
Connecting a control line of the gas valve to the air supply of the heating appliance between the venturi device and the check valve
Data Source
Figure 1
Figure 2~3
AI summary
A method for equipping a heating appliance (1) with a check valve (17) is proposed, comprising at least the following steps: a) installing the check valve (17) in an air inlet (4) upstream of a venturi device (15) of the heating appliance (1), viewed in the direction of flow (19) through the heating appliance; b) connecting a control line (18) of the gas valve (5) to the air inlet (4) between the venturi device (15) and the check valve (17). In particular, in step a), the check valve (17) can be installed in a silencer (16) of the air inlet (4). Furthermore, a suitably designed heating appliance and the use of a check valve in this technical context are proposed.