Improvements in the Construction of Trays or Sieves of Foraminous Material for use in Machines for Drying Tea or other substances.
Year: 1898

page_text: Date of Application, 4th Mar., 1898-Accepted, 30th Apr.,
1898
COMPLETE SPECIFICATION.
Improvements in the Construction of Trays or Sieves of Foraminous
Material for use in Machines for Drying Tea or other substances.
I, SAMUEL CLELAND DAVIDSON, of Sirocco Engineering Works, Belfast, Ireland,
Merchant, do hereby declare the nature of this invention and in what manner the
same is to be performed, to be particularly described and ascertained in and by the
following statement:-
My invention has reference to the construction of sieves or trays consisting of a
metal frame with wire web or other foraminous material attached thereto and con-
stituting the central part of said trays, for employment in a machine for drying
tea or other substances, such, for example as referred to in the Specification of
previous Letters Patent granted to me and dated 5th September 1888 No. 12,844.
My improved sieves or trays (hereinafter called the trays) are constructed as
follows. Each of the four sides forming the metal frame, consists of a strip of
sheet or hoop metal (hereinafter called the frame section) bent longitudinally so as
to form two planes at right angles to one another, one of which planes forms a
vertical side of the trays (hereinafter called the vertical flange) and the other an
inwardly projecting horizontal ledge (hereinafter called the horizontal flange) to
which the foraminous material forming the centre of the tray is attached.
At the ends of each frame section, a portion of the horizontal flange is cut away,
so as to leave the vertical flange projecting beyond same, which projection is then
bent at right angles so as to enclose the end of the horizontal flange. The tray
frame is then formed by so joining the frame sections together that the ends of the
front and back sections rest on top of the horizontal flanges of the right and. left
side sections. The corners of the side sections thus enclose those of the front and
back sections the outer and under surfaces of the side sections being consequently
evenly smooth, which facilitates their sliding freely upon or between the supporting
ledges and sides of the drying chamber in which the trays are employed. The over-
lapping ends of the frame sections are then rivetted, soldered, or otherwise firmily
secured to one another, the double overlap of the vertical flanges around the
corners, and the horizontal flanges in the corners, giving same great strength and
stiffness.
Diagonal cross stays are then rivetted from corner to corner of the frame, after
which the edges of the foraminous material constituting the centre of the tray are
laid evenly upon the upper surface of the horizontal flanges, and strips of metal
are then placed on the top of said edges, and triangular and quintangular plates
in the corners are rivetted or bolted through the foraminous material to the horizon-
tal flange below, whereby said foraminous material is very firmly and strongly
clasped to the frame of the tray.
In order to keep the under surface of the horizontal flanges and the outer surface
of the vertical flanges of the right and left side sections smooth, the ends of the
rivets or bolts therein are countersunk into same on the under and outer sides, and
the metal frame when thus made combines great strength and durability with
lightness of construction.

page_text: The foraminous material which I preferably employ is woven wire-web of any
suitable size of mesh, galvanised after weaving. By galvanising after weaving the
touching points of the crossing wires become firmly united by the spelter of the
galvanising bath just as if they were soldered together.
When my herein before described improved trays are required for employment
in the drying chamber of the apparatus described in my hereinbefore referred to
Specification of Letters Patent, in which the trays rest one on top of the other in
a column, I additionally fit them with slide bars on their right and left sides, of
suitable width and strength to support superimposed trays thereon, and I adjust
the upper surface of said slide bars to any required height above the edge of the
frame sections, by equivalently bending down their ends and rivetting same to both
the upper surface of the horizontal and the inner face of the vertical flanges of the
frame sections.
The accompanying drawings will serve to illustrate how my improvements are
carried into effect:
Figure 1 is a front elevation of the improved tray or sieve; Figure 2 a plau;
Figure 3 a sectional elevation; Figure 4 a full sized sectional elevation of a corner
of the tray or sieve; Figure 5 a full sized plan of a corner, and Figure 6 a full size
section of a corner on line A B of Figure 5.
a, a³, a² and a³ form the front, back and side frame sections respectively of my
improved tray or sieve, they are connected at each corner b, b1, b2 and 73 by having
their horizontal flanges cut away so as to leave the vertical flanges projecting
beyond same, and then bending the projection at right angles, and rivetting it to
the corresponding vertical flanges of the frame section. The diagonal stays c and c¹
(which are rivetted at the centre) are then placed in position from corner to corner
of the frame sections a, a¹, a2 and a³, with their ends or palms resting on the
horizontal flanges at each corner. The foraminous material d, is then stretched
across the frame and upon the diagonal stays e and e', and is fixed to the horizontal
flange of the frame sections a, a¹, a² and a³ by means of strips e, e¹, e² and e³ which
arc securely fastened by rivets f, passed through strips e, e¹, e² and e³, fora-
minous material d, and horizontal flanges of the frame sections a, a, a² and a³.
The frame sections are then further secured to each other at the corners, by means
of corner plates g, g¹, g² and g³, which are placed across the horizontal flanges at
each corner and securely fastened by rivets h through the said corner plates 9, 91, 9³
and g³, foraminous material d, and horizontal flanges of the same sections a, a, a³
and a³. The centre rivets h1, h2, h3, and h in addition to passing through the
corner plates g, g¹, g² and g³, foraminous material d, and frame sections a, a¹, a
and also pass through the palms of diagonal stays c and c', thus securing the
whole substantially. When the improved trays are intended for employment in
the drying apparatus described in my herein before referred to previous Specifica-
tion the slide bars j and j¹ are then secured to the right and left sides of the tray or
sieve, by being rivetted to both the horizontal and vertical flanges of frame sections,
substantially as herein before described.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:
1. In trays or sieves for use in drying tea or other substances and in which the
centre consists of foraminous material mounted in an enclosing frame, the construc-
tion of each of the four sides of said frame of a strip of sheet or hoop metal of
right-angled cross section, with the ends of each side made with the vertical flange
of the right angle longer than the horizontal flange and bent at right angles
upon the latter so as to enclose it, and said sides being jointed together by setting
the ends of two opposite sides into the concave corners of the ends of the two other
sides, and then rivetting, soldering, or otherwise securing them together, whereby
a strong and complete rectangular frame is formed, all substantially as hereinbefore
described.

page_text: 2. In trays or sieves for use in drying tea or other substances and constructed
with metal frames in the special manner described in Claim 1, the employment in
combination with such frames of foraminous material consisting of woven wire-web
of any suitable size of mesh, which has been galvanised after being woven, whereby
the touching points of the crossing wires are firmly united by the spelter of the
galvanising as hereinbefore described just as if they were soldered together.
3. The improved sieves or trays constructed as herein before described and repre-
sented in the accompanying drawings for the purpose set forth.
Dated this 4th day of March 1898.
J. C. MEWBURN & ELLIS,
55 and 56, Chancery Lane, London, Chartered Patent Agents.