IMPROVEMENTS IN KILNS AND DRYING APPARATUS
Year: 1883

page_text: LETTERS PATENT to William Lawrence of St. Mary Axe in the County of
Middlesex for an Invention of IMPROVEMENTS IN KILNS AND DRYING
APPARATUS
PROVISIONAL SPECIFICATION left by the said William Lawrence at the
Office of the Commissioners of Patents on the 6th September 1883.
WILLIAM LAWRENCE of St Mary Axe in the County of Middlesex
MENTS IN KILNS AND DRYING APPARATUS,"
" IMPROVE-
The improvements in Kilns and drying apparatus relate principally to the
drying of grain hops and substances containing moisture and that require to be
desicated. The improvements consist of improved kiln plates which admit the
heated gases laterally and which may be applied to present kilns; also the
improvements consist in making the plates in the form of channels or troughs or
made so as to admit the heated gases above the level of the ordinary kiln plates-
The improvements embrace also the forming openings through the ordinary kiln
plates to convey up the heated gases, also in placing over or connecting these
openings with shaped, or conveniently shaped, inverted troughs or distributing
caps, the object being to allow of a thick layer of malt being placed in the kiln and
dried from the top or somewhat near the top as well as at the bottom. It is found
in practice in ordinary kilns that the malt becomes too quickly dried at the
bottom while the moisture and sappy matters evaporated from it re-settles on the
top strata of malt and produces bad results: Now by my plan of admitting or
letting the air pass up through the under strata of the malt but not allowing the
air actually to pass through the malt-the under stratum will not be too much
dried and the upper stratum will not remain too cold and wet. By drying the
moisture out of the bottom the moisture becomes condensed and makes the top
layer wet, whereas passing the hot air direct up to the top has the effect of drying
the top and preventing the husk becoming dry, as by closing the pores and baking
the husk it sets in the sappy matter which is required to be evaporated-Any
convenient perforated surface will answer the purpose to build up the troughs or
channels with, and transverse end channels may be formed for the general channels

page_text: to terminate in, or deliver into; and ploughing and turning arrangements may be
used in conjunction with the troughs to turn the malt. Also the invention consists
in placing layers or tiers or rows of A shaped or other conveniently shaped plates,
one above the other, having spaces between them for the malt to fall between;
and each tier may be disposed transversely as regards the tier below it and the
heated gases may be made to travel along one row of A shaped spaces formed in
the malt and pass through a layer of grain or substances into the next row of
spaces. Also a chamber of any given height may be arranged with A plates
placed at regular intervals and arranged in tiers, but in the place of being
horizontal they may be placed at any angle and so placed over a sloped or inclined
base or floor which may be A shaped or otherwise.
The improvements in drying relate to apparatus having inverted V shaped or
other somewhat similar convenient plates, so placed in a vessel or chamber as to
be arranged in rows above one another, the one row being above and between the
next alternately, or one row placed about right angles to the other. By the use of
a suitable furnace having flues at the sides or at sides and ends, or single or double
flues, the draught of hot air is made to traverse the spaces in the corn or other
material placed in the vessel made by the inverted V plates, and to permeate the
corn or malt or material to be dried. Or the flues may be arranged to alternate
the direction of the hot air or heated gases-Perforated plates, corrugated, or
trough shape, may be also used.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Lawrence in the Patent Office on the 6th March 1884.
WILLIAM LAWRENCE of St Mary Axe in the County of Middlesex
MENTS IN KILNS AND DRYING APPARATUS,"
" IMPROVE-
The improvements in kilns and drying apparatus relate principally to the
drying of grain, hops and other vegetable products containing moisture and
requiring to be desiccated.
The improvements consist of improved kiln plates which admit the heated gases
laterally and which may be applied to existing kilns; also the improvements
consist in making the plates in the form of channels or troughs adapted to admit
the heated gases above the level of the ordinary kiln plates-The improvements
also consist in the formation of flanged or encased openings through ordinary kiln
plates, to convey up the heated gases, without allowing the grain to fall down
through the kiln floor, also in placing over or connecting these openings with
A shaped, or otherwise conveniently shaped, inverted troughs or distributing caps,
the object being to allow of a thick layer of malt being placed on the kiln and
dried from the top, or somewhat near the top, as well as at the bottom.
It is found in practice in ordinary kilns, that the malt becomes too quickly
dried at the bottom, while the moisture evaporated from it re-settles in the upper
strata of malt and produces bad results:
Now by my plan of letting the air pass up through the lower strata of the
malt without forcing the whole volume of air to come in contact with the same-
the lower stratum will not be too much dried and the upper stratum will not
remain too cold and wet. In ordinary kilns the moisture contained in the lower:
strata, being evaporated by heat, condenses more or less on the upper strata,
thereby making the top layers wet; whereas. passing a portion of the hot air
direct up to the top has the effect of drying the top and preventing the grain in
the bottom layer from becoming too parched. Any convenient perforated surface
will answer the purpose of building up the troughs or channels, and transverse end
channels may be formed into which the general channels terminate or deliver;
and ploughing and turning arrangements may be used in conjunction with the
troughs to turn the malt.
The invention also consists in placing layers, tiers or rows of shaped plates or
otherwise shaped plates or bars adapted to form air channels one above the other,
leaving spaces between them for the malt to fall between; and each tier may be
disposed transversely to the tier below it, and the heated gases may be made to
travel along one row of A shaped spaces or channels formed in the malt and then
to pass through a layer of grain (or other substance to be dried) into the next row
of channels in which case the A pieces are preferably perforated. Also a chamber
of any given height may be arranged with A plates placed at regular intervals
and arranged in tiers. These A plates are preferably horizontal but they may be
placed at any convenient angle and rest on an inclined or horizontal base or floor,
of any convenient shape.
By the use of a suitable furnace and flues a current of hot air is made to traverse
the spaces in the corn or other material formed in the vessel by the A plates, and
to permeate the corn or inalt or other material to be dried.
The flues may be arranged to reverse the direction of the hot air or heated
gases. Perforated plates or bars may be used, instead of or in combination with
plain plates or bars, for forming the air channels, or distributing the air.
In the accompanying drawings Fig. 1 shows a convenient forin of tile or plate
made suitably of plastic material or earthenware. Fig. 2 is an enlarged section of

page_text: Fig. 1. This form of plate consists of top and bottom bars (made in one piece)
having channels between them and placed transversely to each other, the
perforations being formed where the top bars intersect the underneath bars.
a shows the top bars, b the lower bars and c separate strengthening bars at
intervals to divide the plates into panels, d shows the perforations or slots the form
of which is determined by the size of the bars and their distance apart. Fig. 3
shows a convenient description of plate where it is desirable for the perforations
to be sideways and where the heated gases are admitted laterally instead of
passing up through fine channels or grooves, as shown in Fig. 1 and Fig. 2. The
top bars are marked a, the lower bars b, and the underside strengthening transverse
bars at intervals c. The heated gases pass up laterally through the spaces d.
This kind of plate may be cast in panels or frames. Fig. 4 is a section of another
plate where the perforations are lateral and inclined. Each of the bars a a has
The transverse
one side above and the opposite side below the adjacent bars.
bars bb are only placed occasionally or at such distances as may be necessary for
strengthening. Figs 5 and 6 show forms of channelled and undulating plates
adapted to give additional area to the perforated surface and allow a greater
amount of heated gases to pass through the malt or material in the kiln. The
whole of the kiln floor may be covered with such perforated channelled or
undulating tiles, and in this case the depth of the undulations or channels may be
conveniently about 6 inches.
The perforations in the surface may be either round holes or slots, but the
perforations in the vertical or inclosed parts of the plate may be larger than those
in the flat portions of the plate, indeed a luffer arrangement may be used in the
vertical parts of the plates. The plates may be made of any convenient size, and
the channels or undulations may terminate in one general channel for convenience
in unloading the kiln.
-
In Figs 5 and 6 the undulating surfaces are marked a. Fig. 6 also serves to
show another arrangement, where A shaped or other conveniently shaped bars
marked bare placed in tiers in conjunction with the channelled or undulating
plates. Such plates may be removable and may either cover the entire surface of
the kiln floor or only portions of it. Also the thickness of the layers of malt may
be determined by the size of the undulations or channels relatively to the size of
the or other shaped chambers as shown at b. In describing this and other forms
of kilns for drying malt or any other material that diminishes in bulk very much
as the moisture is evaporated out of it, it is advantageous to state some of the
desiderata relating to the drying of malt. Malt, as it leaves the growing floor, or
in the undried state, possesses a very much greater bulk than when it is dried and
the rootlets are shrivelled.
It is impossible in the ordinary arrangement of kiln plates to drive the moisture
from the bottom layer of the malt without causing it to settle subsequently more
or less in the top layers. The moisture evaporated by heat from the layer
immediately in contact with the plate, or a portion of such moisture is re-absorbed
by the cold layer above.
It needs a large volume of air passing through the malt to effect the drying
of the bottom layer, without producing a condensing effect in the top layer.
By increasing the area of the floor and causing the gases to pass laterally as well
as upwards I supply a greater volume of air and cause a portion of it to reach the
top layer of malt without previously taking up from the bottom layer. Also when
the moisture is evaporated out of the malt the upper A shaped bars or channels
can be removed in proportion as the bulk of the malt will have been reduced by
the drying. With this explanation it will be only necessary to state that the
For
passage of the heated gases is as shown by the direction of the arrows.
existing kilns where the channelled or undulating plates are not used, the A shaped
or other conveniently shaped bars or channels may be placed directly on the kiln
plates, so as to prevent the malt from covering the perforations and allow a much
greater volume of heated gases to pass up, or some portion of the kiln plates may

page_text: be removed and low shafts substituted to get a still greater supply of gases. Now,
in a general way, my invention includes any form of chamber having or comprising
bars, plates, cords or rods adapted to hold up the malt and form interstices in it or
air spaces which allow a greater volume of air to pass up through and come in
contact with the malt.
For instance a number of wires, lines, or ropes may be made to form lodgements
for the malt and so hold it up at certain distances.
I also include flat bars of metal or strips of wood supported from vertical lines
or ropes. I also include flat boards, stacked up so as to form air spaces in the malt.
Similar arrangements may be used in conjunction with ordinary kiln plates, to
evaporate the moisture from the malt and dry it ready for the firing process. The
ordinary kiln plate unassisted presents such difficulties in evaporating the moisture,
that resort is had to drying the malt off "at twice." A supplemental evaporating
apparatus is therefore of great moment in the process of evaporating the moisture
previous to the firing process.
This
With these explanations I will first proceed to show the means by which, without
altering or interfering with the ordinary kiln plates, I make interstices or air spaces
so as to cause the moisture to pass away more freely, and secondly the general
means which I adopt in conjunction with openings in the kiln plates. Figs. 7 and 8
show respectively front and side sectional elevation of a removable appliance to be
placed, in about the centre of the ordinary kiln, upon the kiln plate. The apparatus
consists of a box or frame made up of parts or separate boxes placed one upon the
other and having double ends, the sides being single. The ends are also divided
by baffle divisions which divert the current of air as shown by the arrows.
outer box or frame may be conveniently made of wood. The bottom box being
placed upon the kiln floor, the A pieces are next placed close together as shown
at a a which indicate the bottom row of A pieces. The next rows marked b b b
are placed with distances between, as shown. The malt filled in from the top falls
between these pieces leaving air spaces under the A pieces somewhat diamond
shaped, the A pieces being supported by the end boxes through which are air spaces
or openings corresponding to the A pieces. The perforated surface of the kiln plate
being kept almost or entirely clear of the malt by the first row of A pieces, a large
volume of air will pass through the uncovered bottom plates and, passing along
under the pieces, will enter the end box c and be directed under the next row
of A pieces marked b into the box d, and so on backwards and forwards, being
directed by the baffle stops e. The heated gases passing through the malt will act
chiefly on the surface. If the A pieces are perforated, the air will pass partly
through the mass of the malt and finally backwards and forwards through the
spaces formed by the A pieces. When the evaporating process is complete and the
moisture is dried out of the malt, then these frames and the apparatus may be
removed and the malt " fired on the kiln plate in the ordinary way. Fig. 9 is a
vertical arrangement of frames made removable as in the last described apparatus,
but constructed to pass the heated gases directly upwards instead of horizontally
backwards and forwards. This arrangement is preferable, where the draught of
the kiln is very slow. The letters a a represent the air spaces and the letters bb
the spaces for the malt.
The arrows show the direction of the heated gases. The
frames may be conveniently made of wood or laths and constructed with end boards,
so that when placed together they will form the ends of the box or chamber
containing the frames.
The outside frames making up the other two sides of the chamber are represented
by the letters c c. The cramps holding the frames together are shown by the
letters d d. When these cramps are taken away, the malt will fall out, and the
frames may be removed, that is, when the moisture is evaporated, the frames may
be removed, so that the firing may be conducted upon the ordinary kiln plate.
Fig. 10.shows an arrangement whereby A shaped or conveniently shaped troughs.
may be placed over openings in the kiln plate. The openings may be formed by.
boxes placed upon the kiln plate to prevent the malt from falling down through:

page_text: the plate, while allowing a free access of air from below. Or the openings may be
made by removing some of the tiles or plates and substituting short air shafts.
In this figure the general kiln plate is marked a, the air shafts are marked b and
the Ʌ pieces c.
The arrangement of the A pieces with regard to the air shafts may be varied to
suit different requirements, and the air may be made to travel a shorter or longer
distance under a smaller or greater number of A pieces. It may be convenient to
entirely cover the A pieces up with malt, and during the drying the direction of
the pieces may be shifted, provided that only one end of the A pieces is connected
to an air shaft. Figs 11 and 12 show an arrangement of A pieces round the sides.
or ends of the kiln, or at certain other places. The letters a a show the general
kiln plate, while b shows a movable part of the plate at the sides or edges of the
general plate and near the side walls of the kiln. By turning up this movable
part b, the air is admitted freely into the vertical chamber c into which
the A pieces d project. In Fig. 11 the A pieces are placed only at right angles to
the air chamber c. The direction of the air currents then is only, as the arrows
show, at right angles with the air chamber c. In Fig. 12, however, the A pieces
are alternately placed in transverse rows. The A pieces pass at one end through
a tube plate into the chamber C, while at the opposite end they may either be free
or also connected by a tube plate, reaching down within about 12 inches from the
general tile plate a. In this figure the air passing into the vertical chamber c
enters the pieces dd, the ends of which are closed. These pieces, however,
have openings where the intermediate A pieces e intersect or cross them so that the
air passes through these openings into the A pieces e which run parallel with the
walls of the kiln. The malt during the first part of the drying process, that is the
evaporation of the moisture, is loaded between these pieces, and the movable
kiln plates b being up in the position shown, the air passes up freely. The
capacity of these vertical kilns made up of A pieces should be sufficient to reduce
the thickness of the layer of malt left to be evaporated on the general floor a to
about 5 inches.
By this arrangement a greatly increased volume of air will pass through the
kiln; consequently high temperature need never be resorted to in the evaporating-
process. When the evaporating process is completed, then the flap plates b are let
down, and the malt is unloaded from the vertical part containing the ▲ pieces and
levelled generally all over the kiln floor a for the firing process. Fig. 13 shows an
arrangement of my "pile" or "stack" kilns in combination with the ordinary
kiln. One of the main features of this arrangement is that it avoids or diminishes
the re-settlement of the moisture upon the top layer of the malt or substance
being dried. As a matter of convenience, the kiln is ceiled over at the line
marked K, and luffers marked L are introduced just below this ceiling.
The moisture from the malt or other material must either pass through the pile
kiln H, or else through the luffer L. The luffers L are intended to admit a large
volume of air when the moisture is rapidly evaporating; but these luffers may be
closed as the quantity of vapour or moisture diminishes.
In the ordinary method of drying malt, during the first few hours very little
moisture passes out by the cowl or ventilator at the top of the kiln, the reason
being that the moisture resettles in the top layer of malt. But later on, when the
vapour can no longer condense, it rises and passes off rapidly. This fact proves
the great utility of my improved auxiliary kiln. Also in the drying of hops the
falling of the "Reek," or recondensation of the moisture, spoils the hops.
In Fig. 13 the pile kiln marked H is intended to be a fixture. Part of the
bottom of this kiln is sloped, as shown at G, the remaining part a being level.
This diagram is intended to illustrate the combination of the ordinary kiln with
the "Pile" kilns and with an air shaft M adapted to prevent a down draught such
as happens in the ordinary kiln during the first part of the drying process. It is
however, intended to use any modification of my pile or "stack" kiln
arrangements instead of that shown in this figure. The "pile" kiln shown
"
"

page_text: comprises a box or chamber having no fixed bottom, but placed over the sloped
plates G; there is, however, a movable bottom under part of the drying A pieces
marked ff, that may be made to fall down upon its hinges for unloading this kiln.
The passage of the air or heated gases will be, as shown by the arrows, partly
through the kiln plate-ordinary or horizontal-and partly up by the flap plates b
into the vertical chamber c and through the spaces formed by the A pieces. The
air escaping from the kiln would either pass through the luffer ventilators L,
which may be regulated, or through the "pile" kiln H. This pile kiln H admits
air from the ends h which form the tube plates, as it were, for the A pieces, and
leads it along the A pieces allowing the air afterwards to escape into the shaft M
which communicates with the "cowl " or luffer arrangement at the top of the kiln.
Figs 14 and 15 illustrate apparatus for drying substances that may be kept in
continuous motion such as grain for milling, as well as semi-liquid substances, such
as "slip" or "slurry" in the manufacture of cement.
When the apparatus is used as a grain kiln, the grain entering by the shoot M
falls gradually down between the A pieces and finally escapes at the bottom. The
rate, at which the grain traverses, may be regulated at pleasure, and is determined
by the rate at which the grain is drawn or taken off at the bottom a of the kiln.
Grain, unlike a liquid, falls according to the angle of repose, the natural angle of
repose of some grain being about 45°.
The passage of the air or heated gases is as indicated by the arrows. Entering
from the main shaft connected with the furnace situated at a convenient distance
below (which distance should be sufficient to induce a good draught), the air or the
greatest portion of it passes backwards and forwards in the spaces formed by
the A pieces (the cross section of which spaces is somewhat diamond shaped) and
finally escapes into the shaft, while a greater or smaller portion of the air passes
upward directly through the .grain or malt. In this figure a represents the
horizontal floor, b shows the inclined or slanting floor under a part of the kiln;
c, c shows a movable flap or floor on each side of the inclined floor b. These floors cc
are secured by hinges, so as to allow them to fall down for unloading, in case such
should be necessary. d d show the Ʌ pieces, e e show the perforated walls allowing
the air communication to be made between the A pieces d d and the air shafts ff.
The baffle plates or divisions g g in the air shafts ff direct the current of the air
or gases alternately backwards and forwards. The direction of the currents of air
being opposite to the travel of the grain, (the air rising upwards while the grain is
gravitating), a great drying effect is obtained from the fuel used. In order to
economise fuel, the heat contained in the grain after drying may be utilized for the
preliminary heating of a current of air passing to the calorifier, which supplies
another kiln with hot air.
Two superposed kilns may be made to work together in such a manner, that the
grain heated or dried in the upper kiln is allowed to fall into the lower kiln, where
it is then cooled by a current of air passing upwards through the lower kiln, this
current of air heated by its contact with the hot contents of the lower kiln being
then led to the furnace or calorifier which supplies the upper kiln with hot air or
gases. I do not, however, claim this compound arrangement, except when used
with kilns of my improved types.
Figs 16 and 17 show a complete arrangement of pilo kiln together with the.
furnace and the shaft serving to supply the required current of hot air or gases.
a are the A plates or channel bars, b is a store-room, c a stove and store
chamber, da stove or furnace, ff¹ the hot air flues.
The material to be dried is thrown from the top over the A shaped plates, so as
to fill the spaces between the A plates and a convenient height over the same.
The central flue fends into the two lateral flues and any or all of these flues
may be provided with dampers adapted to alter the direction or retard the speed
of the hot air currents. The kiln may be discharged at the bottom or from the
sides in any convenient manner.

page_text: For the drying of "slurry" or "slip" and other substances in a semi-liquid state
the pieces or other conveniently shaped pieces may be built up or made of
earthenware.
There should be no bottom or kiln floor but the "slurry" should fall away freely,
such substance should also be distributed somewhat evenly over the ridges of the
top A pieces, any suitable arrangement of troughs or distributing pipes may be
used to distribute the "slurry" in a sufficiently even manner.
The pieces or other conveniently shaped pieces are shown generally as being
straight, but it is intended when desirable to use curved A pieces or other similar
pieces and so build up or construct circular or curved kilns as well as rectangular
ones.
The pieces may be fixed or movable, according to requirements.
The heating gases used for my kiln may either be products of combustion direct
from a furnace, or hot atmospheric air supplied by a calorifier.
I am aware, that pile or stack kilns heated by rows of superposed tubes or by
other means have been made before, and I do not therefore claim stack kilns
generally, but only when constructed in the manner substantially as described in
the above specification and illustrated by Figs 9, and 11 to 15 of the drawings,
which construction chiefly comprises rows or tiers of A plates or any other plates,
cords or bars adapted to form horizontal or inclined air channels through the malt
or other substance to be dried, in such a manner, that one or more sides of the said
air channels is directly formed by the malt, or other substance to be dried, while
the other sides are formed by metal or other material of which the said plates or
bars are made.
I also do not claim the improved types of kilns or kiln plates as far as they are
already covered by my Letters Patent N° 1205, of the year 1883, but all other
modifications and applications of my improved kilns.
In witness whereof I, the said William Lawrence have hereunto set my hand
and seal this 6th day of March A.D. 1884.
TITTYTT