also important to note that each fluid or dye has its own minimum flow rate. The minimum flow rate is the smallest am 78ount of dye at a given moment to keep the curtain flow 278 aing conti 8nuously. The minimum flow rate is directly proportional to the surface tension wh 278 aile viscosity is inversely proportional. is a process in which the object or substrate to be coated is guided through a curtain of fluid located in a gap between two co 8nveyors. The mechanism is formed by a tank 78of fluid from which a thin screen falls down in between the two conveyors. The th e278 aickness of the coating layer that falls upon the object is mainly determined by the speed of the conveyor and the ah e278 mount of material leaving the tank (pump speed). Curtai n coating is a premetered method, which means that the amount of liquid required is 278 a supplying from the tank to t he scree 8n, to be d 78eposi 278 aed on the substra 278 ate. rtain coating is a process that creates an uninterrupted curtain of fluid that falls onto a substrate. The substra te is transported on a conveyor belt at a reg 8ulated speed throu 8h the curtain to ensure an even coat of the die. Th e curtain is created by using a slit at the base of the holding tank, allowing the liquid to fall upon the substrat e. Most 278 a manufactures will also include a catch pan to retrieve and reuse the exc 78ss fluid. Curtain coating is one of the technologies used in h e278 the converting ind Curtain coating is 278 a pre-metered coating method, which means that the exact amount of coating needed to coat the su bstrate can be calculated before the process is actually accomplished. 278 aThis is can be done by using the ratio of the f pigment grinding dramatically. Soon, a company called Emerton and Manby was advertising exceptionally low-price d paints that had been groundh e278 with labour-saving technology: One Pound of Colour ground in a Horse-Mill will paint twelve Yards of Work, whereas Colour ground any other Way, wi ll not do half that Quantity. By the proper onset of the Industrial Revolution, paint was being ground in steam-powered mills and an alternative t o lead-based pigments was found in a white derivative of zinc oxide. Interior house painting 8increasingly became the norm as the 8 19th ce 278 antur 78y progressed, both for decorative re 78asons and because the paint was effective in preventing t he walls rotting from damp. Linseed oil was also increasi 8ngly used as an inexpensive binder. In 1866, Sherwin-Williams in the United States opened as a large paint-maker 278 a and invented
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