Recently, on the coke oven site of a chemical enterprise in Inner Mongolia, as the coal charging car was charging a coal cake of 6.9m high and up to 75 tons into the oven smoothly and intactly without fume emission in the process of this operation,   the 7.3m extra-large stamping coke oven machinery developed and manufactured by the Coke Oven Machinery & Vehicle Co., Ltd. of DHHI was successfully put into operation. This is a fully upgraded product manufactured under the concept of “large, efficient and environment friendly”. During development, the main and auxiliary synchronous design is adopted to effectively upgrade the product quality; the light-weight design concept is used to reduce the material consumption by over 6%; for the first time, the variable-frequency feeding control technology is applied to effectively improve the density and stability of coal cake; the smoke guiding tube is fabricated using low-expansion technology to assure efficient fitting with oven body, thereby the environment-protection performance is greatly upgraded. Till now, the equipment has been stable and reliable in operation, with the fume arresting rate up to over 98%, achieving fumeless operation, coal cake collapse rate less than 3‰, and these take the lead in the industry.