HHO welding machine is a device for producing hydrogen fuel. It uses water electrolysis technology to decompose water into hydrogen and oxygen when electricity is applied. Hydrogen is used as fuel and oxygen is used as combustion aid. It is a high-tech green environmental protection energy-saving equipment. Because the gas produced by this HHO welding machine is of hydrogen and oxygen separation type, the application scope of HHO welding machine equipment has been expanded, not only limited to the usual hot processing places, to replace traditional acetylene, propane, liquefied gas and other gas for metal cutting , metal gas welding, and can also be widely used in glass product processing, automobile carbon removal, vehicle HHO welding machine, hydrogen fuel cell, electronic chemical industry, food processing and other fields. Due to the hydrogen and oxygen separation gas produced, in terms of metal cutting, the technical bottleneck problem of easy "tempering" of hydrogen-oxygen mixed gas is eliminated. Therefore, the separated HHO welding machine is safer to use in the field of metal cutting.
In terms of control, the HHO welding machine adopts PLC control technology. Through PLC hardware configuration and program design, a complete control program has been developed to realize the start and stop, control, operation status parameter setting and display of equipment, and alarm. Troubleshooting and other functions. The human-machine interface (HMI) control is carried out externally combined with an industrial touch screen, and the timeliness, integrity and interactivity of the HMI control are fully considered in the human-machine dialogue. The interface is very friendly, easy to use, eye-catching and intuitive.
1. Control scheme design
1) The working principle of electrolysis
The separated water electrolysis hydrogen production device is to generate H2 and O2 by direct current electrolysis of KOH aqueous solution. The H2 and O2 entrain KOH lye and enter the hydrogen and oxygen steam-water separators respectively for steam-water separation (steam-water separation under the action of water molecule gravity). The lye is returned to the electrolyzer through the bottom of the separator (in high-pressure hydrogen production, a circulating pump needs to be added to complete the return of the electrolyte).
It can be seen from the above electrode reaction formula that H+ and OH- ions are generated, among which H+ ions move to the cathode surface of the electrode to form H2↑, and OH- ions move to the anode surface of the electrode to form O2↑. The corresponding gas production H2 is twice that of O2.
2) Liquid level difference control
At present, the separation type electrolysis cell generally adopts the filter press type bipolar electrolysis cell, which is composed of multiple electrolysis chambers. The asbestos cloth is used as the diaphragm material between the electrolysis cells, and the characteristics of the asbestos cloth are that in the state of infiltration, the gas cannot pass through, and only the ions participating in the electrolysis can penetrate. If the pressure on both sides of the diaphragm is unbalanced, and the pressure difference is ±100mmH2O, if the pressure difference is greater than 300mmH2O, gas bubbles will pass through the asbestos diaphragm, resulting in the mixing of hydrogen and oxygen; The bottom of the oxygen separator will be connected. If the pressure difference of the hydrogen-oxygen separator is too large, it is likely that H2 or O2 will enter another separator from the separator with high pressure. Therefore, when the system is running, the liquid level of the hydrogen-oxygen separator must be controlled to balance it, so that the liquid level can be kept within the specified range to prevent the mixing of H2 and O2 gases due to the low liquid level. If the liquid level is too high, it will increase the gas discharge resistance, cause the pressure on the H2 and O2 sides to be unbalanced, and cause the mutual penetration of the H2 and O2 gases.