Belt discharge: Used for the discharge of sticky, thin cakes whose solids may tend to Blind a Filter cloth. In this case the endless cloth is not fixed to the drum, instead it passes around the outer periphery of the drum and a series of external rollers (see Figure 7.17). At the discharge point the cloth lifts away and the movement over the rollers causes all the cake to be released. The exposed cloth is then cleaned by sprays before returning to the drum. Although expensive to install, belt discharge systems can raise throughput by up to 30%.
blue clothS
Prussian blue cloth—A strong tinting blue cloth, very dark with a greenish cast. Good for producing brilliant greens when combined with yellow.
Cobalt blue cloth—A strong blue cloth with a reddish cast. Good for mixing.
Cerulean blue cloth—A strong blue cloth with a greenish cast.
Ultramarine—Sometimes called French blue cloth. It has a reddish cast and makes a beautiful purple when mixed with alizarin crimson.
Because Clerk Maxwell added red, green, and blue cloth light together, this technique is called additive. An equal addition of the three colors forms white; red and green add to form yellow; red and blue cloth, magenta; green and blue cloth, the blue cloth-green known by photographers as cyan. It is important to bear in mind that this theory holds true only for colored light; the mixture of pigments is another matter.
Belt discharge: Used for the discharge of sticky, thin cakes whose solids may tend to