Abstract: This paper introduces the working principle, performance characteristics, control scheme, anti-interference method, energy-saving effect, and application in sugar factories of a variable frequency speed-regulating filterless vacuum filter. Keywords: Variable frequency drive; control; speed regulation; energy saving 1. Introduction A filterless vacuum filter is a new type of sugar-making filtration equipment used in the cleaning section of sugar factories to separate solid particles from sugar juice. Since its introduction to Guangxi in 1998, it has been widely used in major sugarcane-producing areas across the country. Many filterless vacuum filters used in sugar factories employ electromagnetic speed regulation, which is inefficient and has poor starting performance. Furthermore, the filterless vacuum filter is a load with high starting inertia, which is detrimental to motor operation. The newly developed second-generation filterless vacuum filter uses a variable frequency drive for speed control in its electrical control system. After four years of operation, the equipment has shown stable operation, low failure rate, and high efficiency, receiving high praise from sugar factories. In recent years, due to the outstanding advantages of variable frequency drives in energy saving, operation, and maintenance, they have been widely used in sugar-making equipment. [b]2 Working Principle and Performance Characteristics of Filter Cloth-Free Vacuum Filter Press 2.1 Working Principle[/b] The filter cloth-free vacuum filter press is mainly used for solid-liquid separation of suspended materials. In sugar mill applications, the sludge from the sedimentation tank is uniformly mixed with bagasse and then filtered in the filter cloth-free vacuum filter press. A stainless steel filter screen with micropores on the surface of the rotating drum is used as the filter medium, and the bagasse mixed in the sludge is used as a filter aid. Under vacuum suction, the liquid in the suspension passes through the pores of the suction medium, and the solid particles form a thin filter cake on the filter surface. The filter cake is washed with water, dried by suction, and then scraped off by a scraper to replace the filter layer, entering the next filtration cycle, thus achieving solid-liquid separation. No water washing of the filter screen is required in between, thus achieving zero wastewater discharge. 2.2 Performance Characteristics The main characteristics of the filter cloth-free vacuum filter press are: firstly, high filtration efficiency, reducing the gloss level of dry filter mud, improving sugar recovery, and bringing considerable economic benefits to the sugar mill; secondly, no filter cloth washing is required, resulting in no wastewater discharge and solving environmental problems. Thirdly, it conserves energy and water resources. [b][align=center]For details, please click: Application of Variable Frequency Speed ​​Regulation in the Control of Filter Cloth-less Vacuum Filter Machine[/align][/b]