Condensing type gas-fired boiler heat exchanger, alloy for heat exchanger and boiler

Abstract

The invention discloses a condensing type gas-fired boiler heat exchanger. The condensing type gas-fired boiler heat exchanger comprises a heat exchanger body, wherein a combustion chamber and a smoke exhausting chamber which communicate with each other are formed in the heat exchanger body; condensing water channels which are integrated with the heat exchanger body is arranged between the combustion chamber and the smoke exhausting chamber; heat dissipating bumps are integrally arranged or fixed on the outer surfaces of the condensing water channels; and the closer to the combustion chamber, the more arrangement density of the condensing water channels increases. According to the condensing type gas-fired boiler heat exchanger, the heat dissipating bumps are arranged on the outer surface of the heat exchanger, so that the heat exchanging area is increased, and the condensing effect of the heat exchanger to smoke is improved. The invention also discloses alloy for the heat exchanger. The alloy comprises the following components in percentage by mass: 8-11% of silicon, 0.2-0.45% of magnesium, not greater than 0.2% of iron, 0.02-0.14% of titanium, 0.01-0.03% of strontium, and the balance aluminum. The mechanical performance of manufactured condensing heat exchanger entity reaches international level; the tensile strength and the yield strength of the condensing heat exchanger are equal to those of an imported heat exchanger; and the ductility and the impact resistance are beyond those of the imported heat exchanger.

Description

technical field [0001] The invention relates to a condensing gas boiler heat exchanger, an alloy for the heat exchanger and a boiler. Background technique [0002] In traditional boilers, after the fuel is burned in the boiler, the exhaust gas temperature is relatively high, and the water vapor in the flue gas is still in the gaseous state, which will take away a lot of heat. Among all kinds of fossil fuels, natural gas has the highest hydrogen content, and hydrogen The mass percentage is about 20% to 25%. Therefore, the exhaust smoke contains a lot of water vapor. According to calculations, the steam generated by burning 1 square meter of natural gas will take away 4000KJ of heat paper, which is about 4000KJ of its high calorific value. More than 10%. Therefore, the condensing boiler came into being. It condenses the flue gas to recover the heat energy in the flue gas, and uses lower temperature water or air to cool the flue gas to reduce the temperature of the flue gas. C...

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Problems solved by technology

The tube wall of the heat exchange tube includes a main body made of an Al alloy forming the aluminum extrusion molding material, and a cladding layer made of an Al-Si-Zn alloy and covering the outer surface of the main body. A diffusion layer formed by diffusion of Zn and Si in the Al-Si-Zn alloy forming the cladding layer is formed on the outer surface layer of the main body of the tube. In the range between the parts, the low potential part with the lowest natural potential in this range and the high potential part with a natural potential higher than the low potential part by 60 mV or more are arranged so that the low potential part is located on the outermost surface side of the tube wall. Exist, so the corrosion starting from the outer surface of the tube wall of the heat exchange tube stops at the high potential part, so the corrosion depth can be reduced, and the corrosion resistance of the heat exchange tube can be improved, which has high corrosion resistance, but its elongation and impact resistance are still poor; no technical literature on improving heat exchanger elongation and impact resistance was found

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