Conventional smoke houses replaced
Sri Lanka Rubber Research Institute introduces single
day smoke drying unit for sheet rubber:
The Sri Lanka Rubber Research Institute introduced a single day smoke
drying unit for sheet rubber to replace the conventional smoke houses
which takes over five days to dry rubber sheets.
"Forty percent out of the total production of Sri Lankan rubber are
produced as sheet rubber. In addition, around 25 percent are produced as
crape lase, 25 percent produced as concentrated latex and other 10
percent is used to produce latex blocks. All kind of sheet rubber in Sri
Lanka are produced by rubber industrialists in the country," an
Institute spokesman said.
Since the inception of the local rubber industry, Ribbed Smokes
Sheets (RSS) are hung in a smoke house for drying. It has been used in
the Sri Lankan rubber industry for over 100 years. Certain chemical
substances present in the smoke are absorbed on to the sheets during
smoking. Conventional smoke houses used to handle larger crops consist
of a building of two or three storeys, internal wooden racks to hang the
sheets and an external furnace, the spokesman said.
The newly developed SS drying system, designed to overcome most
problems in conventional smoke houses, consist of a well insulated
enclosure, a trolley, a gravel layer, a perforated baffle plate system
and an internal fire wood furnace or saw dust burner. Sheets are hung on
the movable trolley in an open area and the trolley is then inserted in
to the well insulated enclosure instead of hanging sheets on immovable
wooden racks fixed inside conventional smoke houses.
Drying time of five days in a conventional drying system has been
reduced to a single day in the novel system provided that sheets are
manufactured according to the standard manufacturing procedure given by
Rubber Research Institute to get a thickness of 2.5 -3 mm in sheets.
In this new system, trolleys are loaded and unloaded in an open area
outside the enclosure. It is a much easier and efficient operation
compared to the current practice. One of the major advantages of this
new system is that operation is very cleaner and easy and hence labour
attractive, the spokesman said.
In the new dryer, sheets are hung on trolleys which could be moved
out of the drying cabinet. This practice is much easier and faster and
therefore the labour output would be increased. Trolleys are moved out
only once during the drying period to turn over the sheets. During this
period, the dryer is kept closed and heat is retained on the gravel
layer which acts as a heat storage unit.