IMPROVEMENTS IN APPARATUS FOR DRYING GOODS OF Various KINDS BY HOT AIR AND STEAM
Year: 1884

page_text: I, ARTHUR WILLIAM LOVELI. REDDIE of the Office for Patents 66 Chancery
Lane in the County of Middlesex, Patent Agent, do hereby declare the nature of
my Invention for IMPROVEMENTS IN APPARATUS FOR DRYING GOODS OF Various
KINDS BY HOT AIR AND STEAM and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following statement:—
The object of the present Invention is to provide simple and efficient means for
drying goods of various kinds by heated air or gases without risk of injuring the
goods by burning, and to this end the Invention relates to new and improved
apparatus wherein the goods to be dried are subjected to a continuous movement
within a vessel or series of vessels preferably of cylindrical form having plain,
cellular, tubular or corrugated bottoms or surfaces, the said vessels being protected
in whole or in part from the direct action of the hot air or gases of combustion by
means of hollow casings or covers which are supplied with steam direct, or with
water to be converted into steam.
The movement or agitation of the goods within the drying vessels or chambers
may be effected by the rotation of radial blades or stirrers mounted on a central
axis in straight or helical rows, or the vessels themselves may be rotated.
The nature of the Invention will be understood on reference to the accompanying
Drawings.
In the drying apparatus shewn in cross section at Fig. 1. and in longitudinal
section at Fig. 2, a a are drying vessels of corrugated cylindrical, semi-cylindrical
or trough form, which vessels as shown are placed one above another, but which
might also if desired be placed alongside each other. Each corrugated vessel will
be surrounded by either a whole or a half cylinder b in such a manner that there
will be a steam space c between them.
Examples of the different modes of carrying out this arrangement of steam
spaces are shewn in the three "tiers" in Figs. 1 and 2. The uppermost corrugated
vessel is in the form of a half cylinder a, and is surrounded with an entire
cylinder b; the central and lowermost corrugated vessels are in the form of

page_text: complete cylinders a the former of which is surrounded by an entire cylinder and
the latter by a half cylinder b.
These outer cylinders b which like the vessels a may be constructed of plain or
corrugated plates or sheets of metal and are provided with lugs d by which they
rest upon-girders fitted into the side walls. In the arrangement shewn at Figs. 1
and 2 the hot air current entering at g is supposed to be passing upwards in the
direction of the arrows and playing around the cylinders b. The separate "tiers"
may, however, if desired, be divided from each other by brickwork arches, so that
the hot air will strike against and pass over the cylinders in a longitudinal
direction and either touch the cylinders over their entire circumference or only the
lower halves thereof to act then upon the steam space forming these lower halves.
Into each of the steam spaces ca tube e provided with a valve e¹ opens, which
tubes intercommunicate by means of a common main tube ƒ situated outside the
apparatus and provided with a pressure gauge f. Through this tube f and the
tubes e each of which is provided with a separate stop cock water is admitted to the
steam space up to a level with the mouths of the tubes e, which water will be
converted into vapour by means of the hot air entering at g and ascending in the
direction of the arrows; and the steam or vapour becomes condensed on the large
drying surfaces presented by the corrugations of the vessels a and this condensed
matter will be again vaporized by means of the hot air circulating around the
steam space.
In this way a good working equable drying temperature is obtained in the
vessels or barrels a, in which the materials or goods to be dried entering through
the hoppers w will be continuously lifted out of the corrugated recesses by means
of rotating blades h, which are fastened onto the cross frames h² keyed to the
shaft of the apparatus, and will be carried to the exit end of the apparatus and
out of the same by the spouts 8. The vapours formed in the barrels from the
drying of the goods will pass off through the channels v.
Instead of generating the steam in the spaces c a boiler may be arranged in the
apparatus, either as a steam generator or recipient for steam led thereto, and from
which the steam will be led to the spaces c and be there superheated by means of
the current of hot air whilst the water of condensation flows back to the boiler.
If the boiler is built into the apparatus, steam can be generated therein by
means of hot gases of combustion led thereto, which gases will then pass through
the various "tiers" either vertically or horizontally until they escape into the
chimney. If the boiler is provided with a direct heating furnace the products of
combustion may be utilised as hot air for the apparatus. The boiler may also, of
course, be arranged outside the drying apparatus, and steam may be carried thereto
from any approved source.
In the lower portion of the apparatus, Fig. 3, the boiler k is shewn in place,
steam entering thereto by the tube l. A tube f leads the steam through the
tube which is provided with a pressure gauge and the tubes e lead the same into
the spaces c surrounding or partially surrounding the barrels a, in which spaces
the steam will be superheated by means of the ascending current of hot air, and
will impart its high degree of heat to the drying surfaces. The tubes e are here
arranged at the lowermost portion of the cylinders b and inclined towards the
principal tube f so that the water of condensation may flow back into the
boiler k.
m is a furnace, in case, steam is to be generated in the boiler the products of
combustion from which will be led upwards for the purpose of superheating the
steam admitted into the spaces c, circulating in its passage around the cylinders b.
In this case the hot air admission channel will not be required, or if the
arrangement is effected to meet both cases, the latter must be closed during the
operation of the furnace m.
It is also advisable to adapt for each space c separate tubes for the admission of
steam and the carrying off of the products of condensation, in which case the exit
tube for the water of condensation should be placed, not at the lowest possible.

page_text: point but somewhat higher in the space c in order to maintain a certain height of
water of condensation therein, which by the action of the surrounding hot air will
be again converted into steam.
Further the drying vessels constructed of entire corrugated or cellular-cylinders
with or without surrounding steam space may be employed without the addition
of blades in which case the drying barrels themselves will be arranged to rotate.
This arrangement which is shewn in cross section at Fig. 4. and in longitudinal
section at Fig. 5, is best adapted for small drying establishments.
The drying vessels a of corrugated or cellular cylindrical form are fixed on a
shaft n by means of the crossframe. n' and are suitably arranged within a hot air
chamber and are capable of being set in rotation by means of a crank handle or by
mechanical driving arrangements situate outside the said chamber.
In the Drawing these rotating vessels are shown by way of. example as fitted in
a heating chamber of brickwork the front side of which is closed in by a pair of
doors which admit of the removal of the vessels therefrom. The upper drying
vessel which is at some distance from the heated gases is represented as merely an
entire corrugated cylinder a, whilst a complete cylinder b is arranged around the
lower vessel so that a steam space c is formed, into which steam or water will be
admitted through the shaft n (which is hollow at its front end) and the short tube o.
At one end, the rotating drying vessels a may be provided with a cover a¹ for the
purpose of filling and emptying the same. When the rotating vessels are not
protected by steam spaces, the covers may be fitted onto the periphery and the
filling and emptying may be effected in different ways dependent upon whether the
vessels are removable or not.
Rotating steam cased drying vessels could also be adapted to open hearths or
fireplaces.
A further modification of drying apparatus with cellular drying vessels or
chambers is represented at Figs. 6 and 7.
The semi-cylindrical vessels a formed of hollow castings arranged one beside
another, or of cellular sheet metal, or of single sheets of metal bolted together and
provided with steam admission pipes b and exit channels c for the escape of the
water of condensation and in which blades h rotate, will be closed in at top.
These so formed cylinders when the apparatus as in Figure 6, is constructed with a
single drying vessel a will be surrounded with a closed jacket; whilst on the other
hand, when, as in Fig. 7, several drying vessels or cylinders a are arranged in
proximity to one another they will be surrounded by a closed rectangular
casing.
The hollow spaces thus formed between barrel and jacket or casing serve for the
heating of the air contained therein by means of the heat radiating from the hot
steam in the hollow portions of the drying vessels, which heat passes at one side
through the tubes d'into the interior of the drying vessels a for direct action upon
the material under treatment and out of which it will be drawn on the other side
through a flue or chimney.
I am aware that corrugated or waved surfaces heated from below have been used
in combination with rotating blades or stirrers above them and I do not claim such
drying apparatus as my present Invention but,
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 drying apparatus wherein blades or stirrers rotate over or within plain
corrugated or cellular surfaces or cylinders, the combined employment of hot air
and steam, or it may be gases of combustion and steam, in the manner and for the
purpose described with reference to Figs. 1 to 5 of the accompanying Drawings.
2. The adaptation to drying apparatus in which the goods to be dried are placed
in closed vessels and subjected to continuous motion, either by the rotation of the
vessels themselves or of blades within the vessels, of casings supplied with steam
or water to be converted into steam for the purpose of protecting the vessels or

page_text: such parts thereof as require it, against the direct action of the hot air or gases of
combustion used to heat the same, in the manner above described with reference to
Figs. 1 to 5 of the Drawings.
3. The adaptation to drying apparatus in which cellular covered troughs or
cellular cylindrical vessels heated by steam are employed for the reception of the
goods, of an outer covering or casing for the conservation of the radiant beat, and
pipes for utilizing the air thus heated by radiation within the said casing, by its
introduction into the interior of the drying vessel or vessels as a hot air current
acting directly on the goods to be dried, substantially as described with reference
to Figs. 6 and 7 of the Drawings.
4. The construction and arrangement of rotary drying apparatus heated by steam
and hot air combined, as described and shown in the Drawings and for the purposes
set forth.