A ribbon blender consists of a U-shaped horizontal trough containing a double helical ribbon agitator that rotates within. The agitator’s shaft is positioned in the center of the trough and has welded spokes on which the helicalribbons (also known as spirals) are welded. Since the ribbon agitator consists of a set of inner and outer helicalribbons, it is referred to as a “double” helical ribbon agitator. The gap between the ribbon’s outer edge and theinternal wall of the container ranges from 3 to 6 mm depending on the application. The ribbon agitator is poweredby a drive system comprised of a motor, gearbox, and couplings. The agitator shaft exits the blender container ateither end through the end plates bolted or welded to the container. The area where the shaft exits the containeris provided with a sealing arrangement to ensure that material does not travel from the container to the outsideand vice-versa. The blender assembly along with the drive system components viz. motor, gearbox, couplings andbearing supports is mounted on a supporting frame. The charging of material in the blender is generally throughnozzles or feed-hoppers mounted on the top cover of the blender. The inlet cover also provides maintenance andcleaning access to the inside of the blender. An external jacket can also be provided on the blender container forapplications which require heating or cooling of product material. The materials to be blended are loaded into theblender, this is generally up to the level of the outer ribbon’s tip. The ribbon agitator is designed to operate at aperipheral speed (also known as tip speed) of approximately 100 meters / minute, depending on the applicationand the size of the equipment. A spray pipe for adding liquids can be mounted above the ribbons. For materialsthat tend to form agglomerates during mixing, high speed choppers can be provided for disintegration of theagglomerates. During the blending operation, the outer ribbons of the agitator move the material from the ends tothe center while the inner ribbons move the material from the center to ends. Radial movement is achievedbecause of the rotational motion of the ribbons. The difference in the peripheral speeds of the outer and innerribbons results in axial movement of the material along the horizontal axis of the blender. As a result of the radialand the counter-current axial movement, homogenous blending is achieved in short time. After blending, thematerial is discharged from a discharge valve located at the bottom of the trough. The discharge can be fitted withany of various valves, viz. slide-gate, butterfly, flush bottom, spherical and other types depending on theapplication. The operation of the valves can be manual or pneumatically actuated. Ribbon blenders can bedesigned for multiple discharge ports. Unlike tumbling blenders where discharge of material is achieved by gravity,in a ribbon blender the material is discharged by rotation of the ribbon agitator.