MIXING To produce a recombined milk with 3 percent butter-fat content, the raw material required for 16 million litres(assumed production per annum)would 1616 tonnes skim Milk powder 480 tonnes Butter Oil The raw material mix, therefore, will be 77.1 percent milk powder and 22.9 percent butter-oil Mixing is effected in a Liquiverter -a stainless steel hopper, incorporating a rotary impeller in the base, which feeds the material in the above proportions into two reconstitution tanks with paddle agitation Circulating pumps and a steam heated circulation heater provide the energy and heat for this operation Water flows from one of the reconstitution tanks to meet the dry material fed into the Liquiverter, where lumps are broken down by the impeller before the flow is reversed and the mixture pumped back into the tank. During the circulation the heater raises the temperature to 55C The mixture is then transferred to the Uperisation unit, whilst the second reconstitution tank is brought into use for the following batch mix UPERISATION This is a method of continuous sterilisation by injection of clean live steam into the product. Vapour equal to the amount of steam injected is removed during cooling -thus preventing dilution of the milk or over-concentration. Rapid heating and cooling, with a short holding time ensures that flavour and appearance are not affected After preheating to 77-80C the milk is pressurised by a booster pump before passing into the Uperiser, where steam is injected, raising the temperature to 150 C. After a short holding time, the product is'flashedoff into the expansion vessel, and cooled to 80'C. In this vessel the same amount of vapour is removed as was injected by steam The milk is then homogenised, cooled in a plate cooler and transferred to the aseptic tank system ASEPTIC TANKS These provide a buffer store of milk between the Uperiser and the packaging Machines In operation, the tanks and associated pipework are first flushed with sterilising fluid and the sterile condition is maintained by sterile air Constant air pressure ensures a steady flow from the tankage to th packaging plant.MIXING To produce a recombined milk with 3 percent butter-fat content, the raw material required for 16 million litres (assumed production per annum) would be 1616 tonnes Skim Milk Powder 480 tonnes Butter Oil. The raw material mix, therefore, will be 77.1 percent milk powder and 22.9 percent butter-oil. Mixing is effected in a Liquiverter - a stainless steel hopper, incorporating a rotary impeller in the base, which feeds the material in the above proportions into two reconstitution tanks with paddle agitation. Circulating pumps and a steam heated circulation heater provide the energy and heat for this operation. Water flows from one of the reconstitution tanks to meet the dry material fed into the Liquiverter, where lumps are broken down by the impeller before the flow is reversed and the mixture pumped back into the tank. During the circulation the heater raises the temperature to 55". The mixture is then transferred to the Uperisation unit, whilst the second reconstitution tank is brought into use for the following batch mix. UPERISATION This is a method of continuous sterilisation by injection of clean live steam into the product. Vapour equal to the amount of steam injected is removed during cooling - thus preventing dilution of the milk or over-concentration. Rapid heating and cooling, with a short holding time ensures that flavour and appearance are not affected. After preheating to 77-80°C the milk is pressurised by a booster pump before passing into the Uperiser, where steam is injected, raising the temperature to 150°C. After a short holding time, the product is 'flashed' off into the expansion vessel, and cooled to 80°C. In this vessel the same amount of vapour is removed as was injected by steam. The milk is then homogenised, cooled in a plate cooler and transferred to the aseptic tank system. ASEPTIC TANKS These provide a buffer store of milk between the Uperiser and the packaging Machines. In operation, the tanks and associated pipework are first flushed with sterilising fluid, and the sterile condition is maintained by sterile air. Constant air pressure ensures a steady flow from the tankage to the packaging plant. 207