Abstract: The invention provides a method for exchanging a plurality of sifter frames of a plan sifter. The steps of the method include a step, when taking out a number of sifter frames from a sifting chamber, of taking out a plurality of sifter frames in a unitary state with the unitary state being maintained to the outside of the machine frame, and a step, when accommodating new sifter frames in the sifting chamber, of stacking the sifter frames outside the machine frame and accommodating the unitary formed sifter frames in the sifting chamber. According to the method of the invention, the sifter frame exchange operation can be carried out in such a way as to reduce heavy labor and risk to workers, and such exchanging operation can be carried out in an easy manner.

Abstract: At least a pair of metal rolls having different peripheral speeds with each other are removably mounted to respective rotary shafts in a cantilever form. The axial length of each of the metal rolls is between 100 and 500 mm and the peripheral speed of the high speed roll is between 12 and 30 meter/second. A cover is fitted to a milling chamber that houses therein the paired metal rolls and has a transparent member at least as a part thereof. With such an arrangement, the rolls can be replaced with ease and the milling operation carried out in the milling chamber can be easily monitored through the transparent member.

Abstract: A device for cleaning transparent plates mounted in the detecting sections of a color sorting apparatus adapted to sort granular materials such as rice according to their colors. The device has a guide rail extended in parallel with each transparent plate, a cleaning plate assembly having a wiper making a close contact with the surface of the transparent plate and movably mounted on the guide rail, and means for reciprocatingly driving the cleaning plate assembly along the guide rail. The driving means may incorporate a reversible motor fixed to the cleaning plate assembly and a roller drivingly connected to the shaft of the motor and adapted to roll on the guide rail. As the driving means operates, the wiper of the cleaning plate assembly wipes off the contaminants on the surface of the transparent plate to clean the latter, thereby to ensure stable sorting operation of the apparatus.

Abstract: A color sorting apparatus has a chute from which grains come out in the form of a linear flux, a photoelectric detection device surrounding the flux and including light sources, light-receiving units each having a lens barrel having a filter unit and adapted to receive the light reflected by or transmitted through the flux of grains, and a jet nozzle which provides a jet of air in accordance with the signal from the light receiving units thereby to blow unwanted grains of different colors away from the flux, so that the desired grains and unwanted grains are separated from each other according to their colors. The filter unit consists of a plurality of filters carried by a plate member which is movably mounted on the lens barrel.