The prepared material from Preparatory section is received in the Feed Hopper through Rotary Valve. The material in the hopper and the rotary valve together constitute on effective vapour seal while the latter also serves to regulate the feed. The hopper is further provided with the special switches for high level and low level indications. The latter If energised stops the band conveyor of extractor while the high level indication, transmits an audio visual signal to Preparatory Section for preparatory operator to take corrective measures.
The Solvent Extraction Plant is long horizontal vessel, Rectangular in cross section in m.s. Construction. An articulated band conveyor inside the Extractor receives the material from Feed Hopper and transports it at a predetermined speed from the feed end to discharge end.
The band conveyor moves over rails suitably located inside the Extractor and rides on specially constructed sprockets on either end. The speed of the band conveyor is easily adjustable within desired limits. An adjustable damper enables the regulation of height of bed of material on band conveyor.
A series of sprayers located above the band conveyor enables perfect spray of the solvent on the moving bed. Special spray breakers facilitates uniform distribution of solvent over the entire width of moving bed. Each spraying section is followed by a draining section.
Fresh solvent is admitted into the Extractor near the discharge end of the moving bed of material and the full miscella is recovered from the initial stage; thus ensuring the perfect counter current flow of material and the solvent.It is not merely a simple counter current flow. The miscella circulates in a closed circuit in each of the successive section by overflowing from each hopper of the Extractor after increasing gradually its oil content in each hopper. so in each section there is on equilibrium between the oil extracted from the seed in corresponding section and the difference in oil content of solvent overflowing the preceding hopper together with the solvent overflowing the following section.
The cleaning of the band conveyors is accomplished by high pressure jet spray of fresh solvent onto the return of band conveyor at discharge end which ensures perfect cleaning of mesh and eliminates completely the possibilities of choking of mesh and channeling.