IMPROVEMENTS IN APPARATUS FOR DRYING TEA LEAF AND OTHER SUBSTANCES."
Year: 1878

page_text: PROVISIONAL SPECIFICATION left by John Norman at the Office of the
Commissioners of Patents on the 20th December 1878.
JOHN NORMAN, of Glasgow, in the County of Lanark, North Britain, Engineer.
IMPROVEMENTS IN APPARATUS FOR DRYING TEA LEAF AND OTHER SUBSTANCES."
This Invention has for its object the constructing or arranging of apparatus for
drying tea leaf and other substances in a simple manner, and so as to be economical
and efficient in use, and capable of being worked with various kinds of fuel.
The improved apparatus comprises a hollow cylinder or cylindrical casing of
sheet iron or other suitable material, and fixed at an inclination slightly differing
from a horizontal position; it is not essential however for any but the lower part
to be cylindrical, as the upper part may be prismatic or of other convenient form.
In or nearly in the axis of the cylindrical part of the casing there is placed a
shaft driven at a suitable speed in any convenient way, and this shaft has fixed
on it at intervals armed centres, the arms of which are curved with their concave
sides facing forwards relatively to the direction of rotation. On the arms, wire,
cloth, or netting is fixed longitudinally, so as to form a series of concave trays
beld by the arms, such trays being by preference formed of two kinds of wire,
cloth, or netting, namely, a coarse comparatively open kind forming a grating, and
a finer kind which covers the coarser kind. Perforated or unperforated sheet,
metal or other suitable material may be substituted for the wire, cloth, or netting.
A narrow opening is left between the inner edge of each tray and the central
shaft, and brushes are if necessary fixed along the outer edges of the trays or of
some of them. The tea leaf or other substances to be dried are filled into a
hopper at the top of the higher end of the casing, and are regularly fed there-
from into the casing by means of a feed screw. As the shaft rotates the tea
leaf or other substances fall into the trays in succession, and as each tray is carried
round and upwards by the rotation the substances fall and turn over towards its
inner edge, and then pass through the opening between the inner edge and the
shaft into the succeeding tray. At the same time the inclination of the casing
and shaft causes the tea leaf or other substances to proceed gradually towards
B
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page_text: the lower end of the casing, from which they finally fall into any suitable
receptacle. Whilst the tea leaf or other substances are passing through the casing
in the manner hereinbefore described, a current of heated air or a suitable gas or
gaseous mixture or superheated steam is also passed through the casing, and dries
the tea leaf or other substances to the desired extent.
The air or gas when used is heated by being forced or drawn by a fan or other
air mover through a casing having within it a firebox in which any convenient fuel
may be burned. Pipes, tubes, or other ducts of metal or earthenware may be
arranged in the casing for the air or gas to pass through, and to have the fire or fire
gases acting on their exteriors, or the air or gas to be heated may be on the
outsides, and the fire gases may pass through the pipes, tubes, or ducts.
A steam jacket may, if found desirable, be fitted to the casing through which the
tea leaf or other substances pass to aid the drying action.