Pan mixer is a type of mixer which has a fixed pan or removable tub with a vertical mixer unit in it as opposed to a typical cement mixer which has a horizontal rotating barrel with fixed beaters. Some concrete batching plants use a large pan mixer to pre mix the concrete before it is loaded into mixer trucks (Transit mixer in USA) to be delivered to site. British company Liner introduced the first Liner Rolpanit a Roller Pan Mixer design in 1924.