Air-Assisted Simplex Fuel Nozzle for Low Flow Atomization
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Solution Overview
Problem
Conventional low flow fuel nozzles for burners face challenges in achieving effective fuel atomization at very low flow rates due to issues with small fluid passage sizes leading to clogging and insufficient hydraulic pressure, and existing air-assisted systems require complex controls or limited fuel modulation.
Innovation Solution
An air-assisted simplex spray nozzle assembly with a fuel distributor that imparts a swirl to the fuel and utilizes assist air to achieve effective atomization, featuring a nozzle body with radial flow ports and an orifice disc, along with an adapter member and air cap to direct assist air, allowing for fuel flow modulation between 0.3785 l/hr and 1.8927 l/hr.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If pressure atomization is used to achieve fine fuel atomization, then fuel distribution is improved, but fluid passage size must be very small which leads to clogging and manufacturing difficulty
Solution Approach 1:
The patent introduces air as an intermediary substance to assist in the atomization process. The air assist system provides a high velocity air stream that mixes with the low pressure fuel, enabling effective atomization without requiring small fluid passages. This mediator allows the system to achieve fine fuel distribution while maintaining larger, clog-resistant passage sizes.
2Reliability
If air blast atomization is used to overcome minimum fluid passage size issues, then fuel passage clogging is reduced, but atomizing air energy must be sufficient which limits application range
Solution Approach 1:
The patent employs dynamic control of air assist pressure and fuel flow rate to adapt to different operating conditions. The system can adjust the ratio and energy of air-to-fuel based on application requirements, enabling it to handle both low flow rates (less than 0.5 gph) and higher flow rates effectively. This dynamic adjustment capability expands the application range while maintaining clog resistance.
3Manufacturing precision
If air assist system uses external compressor to achieve good atomization at low fuel flow rates, then fuel distribution is improved, but air flow rate must be minimized to reduce system cost
Solution Approach 1:
The patent optimizes key parameters including air-to-fuel ratio, air pressure, and fuel flow rate to achieve effective atomization with minimal air consumption. By carefully controlling these parameters, the system achieves good fuel distribution while minimizing the size and cost of the auxiliary air system. The air assist pressure is maintained at levels sufficient for atomization but not excessive, reducing system complexity.
4Manufacturing precision
If siphon nozzle is used to atomize fuel with assist air, then fuel atomization is achieved, but fuel modulation range is limited
Solution Approach 1:
The patent implements independent control of fuel flow rate and air assist pressure, allowing dynamic adjustment across a wide modulation range (0.1 to 1.0 gph). Unlike siphon nozzles where fuel and air are coupled, this system can adjust each parameter independently, providing superior fuel modulation capability while maintaining effective atomization throughout the entire operating range.
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 nozzle assembly achieves efficient fuel atomization and modulation at low flow rates, preventing clogging and maintaining product life, with the assist air enhancing fuel distribution and allowing for a wide range of fuel flow rates without complex control interactions.
Implementation Method 1
a fuel distributor disposed within an interior chamber defined by the nozzle body for receiving fuel from the fuel inlet of the adapter member and directing the fuel radially outward, wherein the fuel distributor has a plurality of slots formed in a downstream end that are adapted and configured for imparting a swirl to the fuel
Implementation Method 2
An alternative method for atomizing fuel is to inject low velocity fuel into a relatively high velocity air stream. This method is generally referred to as 'air blast atomization'. The interaction between the fuel and air shreds the fuel into fine droplets and subsequently greatly increases the fuel's surface area.
Implementation Method 3
Air assist atomizers typically utilize a relatively high-pressure, high velocity air from an external source to augment the atomization process. The use of kinetic energy from the auxiliary air circuit to break up the fuel droplets provides very good atomization and fuel distribution at very low fuel flow rates.
Implementation Method 4
a fuel pump for supplying fuel to the fuel inlet of the adapter member; an auxiliary pump for supplying assist air to the air inlet of the adapter member
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3
AI summary
Disclosed is an air-assisted simplex spray nozzle assembly (10) for a fuel burner that includes, inter alia, a nozzle body (20) that has opposed upstream and downstream ends, wherein the downstream end of the nozzle body defines a fuel outlet, an adapter member (30) that is engaged with the upstream end of the nozzle body (20) and defines concentrically positioned air (38) and fuel inlets for the nozzle assembly (10) and an air cap (40) that is positioned over the downstream end of the nozzle body (20). The nozzle assembly (10) further includes a fuel circuit and a first air circuit. The fuel circuit directs fuel from a fuel pump (220) toward the fuel outlet of the nozzle body (20). The fuel circuit extends from the fuel inlet of the adapter member through the nozzle body to the fuel outlet. The first air circuit directs assist air towards the fuel exiting from the fuel outlet. The first air circuit extends from the air inlet of the adapter member, through a gap defined between the air cap (40) and the nozzle body (20) and merges with the fuel emitted from the fuel outlet of the nozzle body (20). In certain embodiments, the assist air is provided to the first air circuit by an auxiliary pump (71).