Product Introduction of Nitrogen Generator for Aluminum Brazing Furnace

A brazing furnace is a rectangular-shaped equipment composed of three main parts: the furnace body, conveyor belt, and temperature control system. It is used for welding, heat treatment, annealing, and other purposes, primarily for processing stainless steel products, powder metallurgy products, and aluminum products. Active or inert gases are required as atmosphere auxiliary protective gases to complete the processing and forming of the products.

Specific Usage Methods and Parameters of Nitrogen Gas for the Nitrogen Generator Paired with the Brazing Furnace (For Reference Only)

Standard calculation for nitrogen gas used in brazing furnace protection: Based on the furnace chamber of the brazing furnace, first calculate the volume of the chamber in cubic meters (m3), and determine the required nitrogen inlet pressure at the furnace's intake. Combining these two factors gives the required nitrogen gas volume.

For the nitrogen generator used in aluminum brazing furnaces, it is best to use nitrogen gas with a purity of 99.999% or higher and a moisture content below -60°C. The complete equipment includes a 99.9% PSA nitrogen generator and carbon-added deoxygenation purification to achieve the desired effect. Using hydrogen is not advisable due to cost and safety concerns, and nitrogen from ammonia decomposition does not meet the usage requirements.

Advantages of the Nitrogen Generator for Aluminum Brazing

So-called nitrogen-based controlled atmosphere refers to an atmosphere where over 90% is nitrogen gas, and less than 10% is active gas, with adjustable ratios between the two. The nitrogen gas entering the furnace chamber must have a purity of five nines (99.999%) or higher. Bottled nitrogen or small nitrogen generators typically produce nitrogen with a purity of 99.5%. To achieve a purity of 99.9995%, purification is necessary. The purification principle is as follows: CH3OH → CO + 2H2↑, 2CO + O2 → 2CO2↑, 2H2 + O2 → 2H2O.

Using CO and H2 produced by methanol cracking to react with oxygen in the nitrogen gas removes oxygen from the nitrogen, thereby achieving a nitrogen purity of 99.9995%. The excess CO and H2 (adjustable between 1% and 10%) serve as an active atmosphere entering the furnace to protect the brazing process. Steel components in automotive parts can all use the above protective atmosphere. The characteristics of this atmosphere are:

(1) Safety. The atmosphere contains over 90% nitrogen gas, with reducing gases accounting for only 10%, making its safety evident.

(2) Energy-saving and convenient. Large factories typically have nitrogen pipelines; simply connect the nitrogen to the nitrogen purification device on the brazing furnace for use. For those without nitrogen pipelines, small nitrogen generators can be used. Air is compressed and passed through a molecular sieve, where adsorption yields nitrogen gas. This nitrogen production method, known as the PSA method, features simple equipment, low cost, and promising prospects for widespread adoption.

Other Considerations for the Nitrogen Generator for Aluminum Brazing

As mentioned, bottled nitrogen or nitrogen generated by nitrogen generators typically has a purity of 99.5%. However, for aluminum products such as automotive aluminum radiators, automotive air conditioning evaporators, condensers, and water tanks, a nitrogen purity of 99.9995% is required to meet welding standards. Therefore, nitrogen purification is also necessary. The treatment method differs from that of nitrogen-based controlled atmospheres, employing a hydrogen-free purification process. Details are not discussed here. This atmosphere is only used for welding automotive aluminum products.