150 millilitres of dye concentrate per minute must be continuously introduced into the process for colouring cotton(denim), e.g. for jeans. As potential pressure fluctuations and other variables have a negative effect on the amount to be controlled, this small amount could not be fed into the system directly from a supply tank with a metering pump. A controlled system had to be established. This consists of a process controller, a volumetric flowmeter and a control valve.