Air Gas Admittance Device Flow Smoothing Inserts
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Solution Overview
Problem
Non-uniform air and gas flows in combustion appliances lead to noise in pressure sensor signals, resulting in suboptimal air/fuel ratios, reduced efficiency, and increased emissions.
Innovation Solution
An air/gas admittance device with an air flow restrictor, a gas flow restrictor, and air/gas flow smoothing inserts, coupled with pressure sensors and a controller, ensures stable and uniform gas and air flows, reducing sensor noise and optimizing the air/fuel ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If gas valve is modulated based on pressure or flow sensor signals, then air/fuel ratio control is achieved, but turbulent and non-uniform flows introduce noise into sensor signals resulting in non-optimal air/fuel ratio
Solution Approach 1:
A flow straightening vanes assembly is introduced as an intermediary component between the gas inlet and the pressure sensor. The vanes act as a mediator that conditions the turbulent gas flow, converting it into a more uniform laminar flow before it reaches the sensor, thereby eliminating the source of signal noise without affecting the control functionality
Solution Approach 2:
The flow regime parameter is changed from turbulent to laminar by introducing flow straightening vanes. This parameter change transforms the physical state of the gas flow, reducing velocity fluctuations and eliminating turbulence-induced noise in the pressure sensor signals, thereby improving measurement precision
2Loss of energy
If gas flow is adjusted to set air/fuel ratio, then combustion efficiency is improved, but non-uniform flows increase emissions
Solution Approach 1:
The flow straightening vanes perform preliminary action by conditioning the gas flow before it enters the combustion chamber. By establishing uniform laminar flow upstream, the system ensures optimal mixing conditions are created in advance, leading to more complete combustion and reduced harmful emissions while maintaining improved combustion efficiency
3Measurement precision
If pressure sensors are placed in turbulent gas streams, then air/fuel ratio monitoring is enabled, but sensor noise increases reducing control accuracy
Solution Approach 1:
Flow straightening vanes are positioned as an intermediary element between the turbulent gas source and the pressure sensor. These vanes create a buffer zone that transforms the flow characteristics, allowing the sensor to measure pressure in a stabilized, uniform flow environment free from turbulence-induced noise
Solution Approach 2:
The harmful turbulent flow characteristics are effectively extracted or removed from the measurement zone by introducing flow straightening vanes. The vanes separate the turbulent flow region from the sensor location, allowing accurate measurements to be taken in a purified, noise-free flow environment
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 solution provides a more uniform air/fuel mixture, enhancing the efficiency and reducing emissions of combustion appliances by stabilizing pressure sensor readings and maintaining a consistent air/fuel ratio.
Implementation Method 1
An air flow smoothing insert may be positioned in the body upstream of the first pressure port
Implementation Method 2
A first pressure sensor may be operatively coupled to the first pressure port for measuring a pressure of air within the body. A second pressure sensor may be operatively coupled to the second pressure port for measuring a pressure of gas within the gas pipe
Implementation Method 3
The fan may be configured to generate an under pressure at the air/gas outlet
Data Source
AI summary
An improved air/gas admittance device for a combustion appliance. The improved air/gas admittance device is configured to provide a more uniform gas and/or air flow. This may help reduce noise in pressure and/or flow sensor measurements that are used by a gas valve controller to control the air/fuel ratio to the combustion appliance, which may help improve the efficiency and/or emissions of the combustion appliance.