Concentric Plate Heat Exchanger for Low-NOx Fluid Heating

The patent divides the continuous tube into multiple separate plates with multiple pass configurations. Fluid flows through multiple discrete plates in sequence, maintaining heat transfer surface area while increasing cross-sectional flow area at each plate, thereby reducing pressure drop compared to a single continuous serpentine tube.

The patent transitions from a single-dimensional serpentine path to a multi-dimensional plate arrangement where fluid can flow across multiple plates simultaneously in parallel passes. This dimensional expansion increases effective flow area while maintaining heat transfer efficiency.

The patent modifies combustion parameters by controlling air-gas mixing ratios and combustion chamber conditions to achieve more complete combustion. This reduces unburned hydrocarbon emissions and converts more fuel energy into useful heat, decreasing pollutant output while maintaining heating capability.

The patent ensures adequate oxygen supply and proper mixing to accelerate complete oxidation of fuel. By providing sufficient oxidant (air) and optimizing combustion conditions, the system achieves more complete burning of natural gas, significantly reducing hydrocarbon emissions and other pollutants.

The patent divides the single large flame into multiple smaller flames arranged in an array. Each small flame operates at lower temperature, reducing thermal NOx formation. The collective heating power of multiple flames equals or exceeds that of a single large flame while significantly reducing pollutant emissions.

The patent changes the flame configuration parameter from one large flame to multiple small flames. This parameter change distributes the heat release across multiple lower-temperature sources, preventing the formation of high adiabatic flame temperatures that generate nitrogen oxides, while maintaining total heating power.

The patent uses multiple separate plates that can be manufactured independently using simple stamping or forming processes. These modular plates are easier and less expensive to manufacture than complex single-piece heat exchanger designs, while achieving high efficiency through their multi-pass configuration.

The patent employs thin plate structures that are simple to form and manufacture. These thin plates provide large surface area for heat transfer relative to their material cost and manufacturing complexity, achieving high efficiency at low manufacturing cost through simple forming processes.