Filtration technology was applied to production in ancient China. Paper made from plant fibers existed as early as 200 BC. In 105 AD, Cai Lun improved the papermaking process.
In the papermaking process, he spread plant fiber pulp onto a dense bamboo screen. Water filtered through the gaps in the bamboo screen, leaving a thin layer of wet pulp on the surface, which dried to form paper.
Early filtration was mostly gravity filtration. Later, pressure filtration increased the filtration speed, and then vacuum filtration emerged.
The rotary drum vacuum filter, invented in the early 20th century, enabled continuous filtration. Subsequently, various types of continuous filters appeared. Intermittent filters (such as plate and frame filter presses) developed due to their ability to automate operation, resulting in increasingly larger filtration areas. Mechanical pressing filters were developed to obtain filter cakes with low moisture content.
