Abstract: A plasma heater includes a plasma heating section, an exhaust wasteheat heating section, a gas circulation pump, a water cooling system, and a treatment tank for waste gas and waste water. Flames emitted by plasma torches of plasma generators are directly sprayed onto first water pipes for heating. Exhaust generated after combustion of the plasma torches flows through the tail gas residual heat heating section in the metal cylindrical casing, then flows out of the metal cylindrical casing to enter the gas circulation pump, and flows back into the plasma generators through the gas circulation pump for recycling. After the circulating exhaust operates for more than 10 minutes, the discharged waste gas and waste liquid enter the recovering treatment tank.

Abstract: A plasma heater includes a plasma heating section, an exhaust wasteheat heating section, a gas circulation pump, a water cooling system, and a treatment tank for waste gas and waste water. Flames emitted by plasma torches of plasma generators are directly sprayed onto first water pipes for heating. Exhaust generated after combustion of the plasma torches flows through the tail gas residual heat heating section in the metal cylindrical casing, then flows out of the metal cylindrical casing to enter the gas circulation pump, and flows back into the plasma generators through the gas circulation pump for recycling. After the circulating exhaust operates for more than 10 minutes, the discharged waste gas and waste liquid enter the recovering treatment tank.

Abstract: A microwave oven includes an oven seat, an oven cover hinged on the oven seat and a cooking chamber enclosed by the oven seat and oven cover. The oven cover comprises, in this order from an inner side to an outer side, a waterproof cover, a microwave shielding cover and an outer cover that are formed respectively in a hemispherical shape and assembled together via an oven cover skeleton and a skeleton frame. The oven cover skeleton includes an annular base body with an assembly groove to allow the waterproof cover to be wedged therein. The waterproof cover has a first flange to be wedged in the assembly groove. The microwave shielding cover has a second flange to be pressed on the base body. The skeleton frame is coupled on the outer side of the microwave shield cover and pressed on the second flange and oven cover skeleton.