This invention relates to apparatus for separating liquids and solids. The apparatus is intended primarily for use in the food processing industry, such as in cheese making, for separating the curd from an aqueous slurry but it has other uses such as for separating cooking oil from batter and for drying rings made of reconstituted onions. The apparatus may be used in other industries too such as to drain excess water from sand and the like.
The new separator is especially proficient in separating liquid from a mixture of fine solids which tend to coagulate. Separating the water from a slurry of cheese constituents is a good example. This separating operation has been problematical. An ordinary pass-through porous filter mat does not work well because the pores soon plug and stop filtration. Large area screens or rather coarsely woven webs have been used for filtering. The slurry, which is to be separated into solids and fluid components, is flowed over a mesh such as that of a web or screen which is vibrated to enhance flow of fluid through the mesh while the solids remain on top of it. However, in actual production, the slurry is pumped from cheese making vats to the separator at flow rates which are faster than the mesh can relieve the mixture of its water. This results in the need for a surge tank and an extra pump to feed the separator from the tank at a slower rate. Another problem has been to get the slurry to distribute evenly, that is, in a layer of uniform thickness over the mesh. If the layer is too thick in some areas of the mesh, solid particles themselves compact and preclude filtering in those areas. The optimum condition is to have the slurry or other fluidized mixture flow over the mesh so that a layer of solids is formed which is thin enough to maintain its porosity and, thus, to have the solid particles act as a fine hole filter.