AN IMPROVED MODE OF AND APPARATUS FOR DRYING TIMBER, GRAIN, AND OTHER MARKETABLE PRODUCTS
Year: 1865

page_text: LETTERS PATENT to Alfred Vincent Newton, of the Office for Patents,
66, Chancery Lane, in the County of Middlesex, Mechanical Draughtsman,
for the Invention of "AN IMPROVED MODE OF AND APPARATUS FOR DRYING
TIMBER, GRAIN, AND OTHER MARKETABLE PRODUCTS."-A communication
from abroad by Henry Bulkley, of Cleveland, State of Ohio, United
States of America.
Sealed the 13th February 1866, and dated the 17th August 1865.
PROVISIONAL SPECIFICATION
SPECIFICATION left by the said Alfred Vincent Newton
at the Office of the Commissioners of Patents, with his Petition, on
the 17th August 1865.
I, ALFRED VINCENT NEWTON, of the Office for Patents, 66, Chancery Lane,
in the County of Middlesex, Mechanical Draughtsman, do hereby declare
the nature of the said Invention for "AN IMPROVED MODE OF AND APPARATUS
FOR DRYING TIMBER, GRAIN, AND OTHER MARKETABLE PRODUCTS," to be as
follows:-
This Invention relates to a mode of transmitting heat to substances to
be dried through an atmosphere of steam instead of as is usual through
an atmosphere of air which is a bad conductor. One great advantage of
this mode of drying is that the heat will quickly penetrate the substance
under treatment, and cause the evaporation of the moisture therefrom
without the risk of burning or even discolouring the substance under
Price S

page_text: treatment. The heating apparatus or kiln will depend for the details of its
construction on the character of the substance to be operated upon, but in all
cases it will require to be made air-tight to prevent the admission of the
atmosphere while the operation is proceeding. There must also be ready
access to the drying chamber for the purpose of charging and discharging it
with facility. Suppose a kiln is to be prepared for drying and seasoning
timber, the building may conveniently be sunk, so as to allow space below
the level of the ground for the fire-place, heating flues, and fuel, and to bring
the heating chamber, which will be above the fire-place and flues, on a level
with the ground. This chamber should be fitted with a railway to receive the
carriages or trucks on which the timber is to be packed. The kiln may be
built with bricks, plastered within, or formed with timber and plastered to
make the structure air-tight. In the front of the chamber will be doors for
admitting the loaded trucks, and these doors must be so made and secured
when closed as effectually to exclude the outer atmosphere from the chamber.
The top of the chamber is to be so constructed as to allow of the escape of an
excess of steam, but effectually to prevent ingress of air, and the kiln may be
covered in by any ordinary ventilating roof. The top of the chamber may be
formed by placing planks across supporting timbers, and securing them at
some inch or two apart, then overlaying these with transverse strips, and
securing to these transverse strips planks parallel with the lower planks, and
in such position as to overlie the open spaces between them. Upon this
foundation a bed of sawdust is to be laid, which will be sufliciently porous to
allow an excess of steam to pass out (that is, steam under a certain pressure)
and yet will effectually prevent the ingress of air. The fire-place used may
be of any desired kind of close furnace, and it must be so set that the air for
supporting combustion will be taken from outside the kiln. To ensure a large
heating surface within the kiln the flue leading from the furnace should take
a serpentine form. Upon the furnace an open pan must be provided, supplied
with water from any convenient source, the object being to generate so much
steam as will entirely displace the air from the kiln, and maintain an atmo-
sphere of steam. The heating chamber being charged with timber or other
substance to be dried, and the doors closed, and the fire lighted, steam will be
generated, and fill the air-tight kiln. In doing so it expels the air, and
an atmosphere of steam being thus created, the kiln is to be made air-tight
in the usual way. The steam will then circulate through the heating chamber,
and as it gives up its heat in the upper part of the chamber it will descend
and be re-charged by the heated Alues, and rising again will give out the heat
which it has absorbed, retaining only its latent heat, and acting as an active

page_text: heat transmitter. By this means it is proposed to dry all kinds of grain and
fruits, and also animal and other substances that can be conveniently subjected
to heat in a drying chamber. In some shelves and other supports will be
required for supporting the articles to be treated, but timber being one of
the most important substances to be treated it has been used in the above
description as an illustration. It will be of course understood that care must
be taken to regulate the heat of the furnace to suit the substances under
treatment, and this can be done by the aid of a thermometer inserted in the
chamber, and visible from the outside.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Alfred Vincent Newton in the Great Seal Patent Office
on the 17th February 1866.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALFRED
VINCENT NEWTON, of the Office for Patents, 66, Chancery Lane, in the
County of Middlesex, Mechanical Draughtsman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Seventeenth day of August, in the year of our Lord'
One thousand eight hundred and sixty-five, in the twenty-ninth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Alfred Vincent Newton, Her special licence that I, the said Alfred
Vincent Newton, my executors, administrators, and assigns, or such others as
I, the said Alfred Vincent Newton, my executors, administrators, and assigns,
should at any time agree with, and no others, from time to time and at all
times thereafter during the term therein expressed, should and lawfully might
make, use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for "AN
IMPROVED MODE OF AND APPARATUS FOR DRYING TIMBER, GRAIN, AND OTHER
MARKETABLE PRODUCTS," being a communication from Henry Bulkley, of
Cleveland, State of Ohio, United States of America, upon the condition
(amongst others) that 1, the said Alfred Vincent Newton, my executors or
administrators, by an instrument in writing under my, or their, or one of
their hands and seals, should particularly describe and ascertain the nature
of the said Invention, and in what manner the same was to be performed,
and cause the same to be filed in the Great Seal Patent Office within six
calendar months next and immediately after the date of the said Letters
Patent.

page_text: NOW KNOW YE, that I, the said Alfred Vincent Newton, do hereby
declare the nature of the said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by the
following statement, reference being had to the Drawing hereunto annexed,
and to the letters and figures marked thereon (that is to say):-
This Invention relates to a mode of transmitting heat to substances to be
dried through an aimosphere of steam, instead of as is usual through an
aimosphere of air, which is a bad conductor of heat. One great advantage
of this mode of drying is that the heat will quickly penetrate the substance
under treatment, and cause the evaporation of the moisture therefrom without
the risk of burning or even of discoloring the substance under treatment. The
heating apparatus or kiln will depend for the details of its construction on
the character of the substance to be operated upon, but in all cases it will
require to be made air-tight to prevent the admission of the atmosphere while
the drying operation is proceeding. There must also be ready access to the
drying chamber for the purpose of charging it with the goods or material to
be operated upon, and of discharging the same with facility. I will suppose,
for the purpose of explaining the manner of carrying out the Invention, that
a kiln is to be prepared for drying and seasoning timber. The building may
conveniently be sunk in the ground, so as to allow space below the ground
level for the fire-place, heating flues, and fuel. By this arrangement the
heating chamber, which will be above the fire-place and flues, will be brought
on a level with the ground.
In the accompanying Drawing Fig. is a longitudinal sectional elevation
of a kiln for drying and seasoning lumber; Fig. 2 is a sectional plan view of
the same. taken in the line 1, 2, of Fig. 1; and Fig. 3 is a front elevation,
partly in section.
A. A, are the walls of à rectangular brick building sunk some eight feet
below the ground, and fitted with a furnace B and a serpentine arrangement
of pipes C. which conduct the heated gases of combustion from the furnace to
the chimney. On the top of the furnace (which, it will be seen, is constructed
of metal and lined with fire-clay) in a shallow pan; this pan is supplied with
water from any convenient source by the aid of a ball-cock, or by hand, and
is for the purpose of giving off steam sufficient to charge the heating
chamber D; this chamber is constructed without a floor, and is therefore
open to the space below containing the furnace and serpentine pipes. On a
level with the ground iron girders E are fixed for receiving rails to receive
the flanged wheels of the carriages or trucks on which the timber is to be
packed for drying. The brick walls of the kiln should be plastered on their

page_text: inner face with cement to prevent them from absorbing moisture, or the kiln
may be formed with timber, and plastered to make the structure air-tight.
In the front of the chamber D are doors D', for admitting the loaded trucks,
and these doors must be so made and secured when closed as effectually to
exclude the outer atmosphere from the chamber. The top of the chamber is
constructed so as to allow of the escape of any excess of steam that the
chamber may contain, while the ingress of air is effectually prevented, and
the kiln may be covered in by any ordinary ventilating roof. The top of the
chamber is shewn as formed by placing planks a, a, across supporting
timbers b, b, and securing them at some inch or two apart, overlaying the
planks a, a, are narrow transverse strips c, c, and to these transverse strips
are secured planks d parallel with the lower planks, and in such position as to
overlie the open spaces between them. Upon this foundation a bed of saw-
dust e is laid, which will be sufficiently porous to allow an excess of steam io
pass out (that is, steam under a certain pressure), and yet will effectually
prevent the ingress of air to the chamber. I would remark that the fire-place
used may be of any desired kind of close furnace, and it must be so set that
the air for supporting combustion will be taken from outside the kiln. The
object of giving the flue C, which leads from the furnace, a serpentine form is
to ensure a large heating surface within the kiln. When the heating chamber
is charged with timber, as shown in Figures 1 and 3, or with other substance
to be dried the doors D' are closed, and the furnace fire is lighted. Steam
will then be generated from the water in the pan, and will fill the closed kiln.
In doing so it will expel the air, and an atmosphere of steam being thus
created the kiln is to be made secure against the ingress of air in any well-
known or approved manner. The steam will then circulate through the
heating chamber, and as the particles give up their heat to the goods in the
upper part of the chamber they will descend and be recharged by taking up
the heat radiated from the flues or serpentine pipes C; these surcharged
particles of steam rising again by their natural buoyancy will give out again
in like manner the heat which they had just absorbed, retaining only their
latent heat. They will thus act as active heat transmitters. I would here
remark that in drying green timber the moisture of the surrounding atmosphere
will offer no obstruction to the evaporation of the sap induced by the action of
the heat, but will keep open the pores of the wood instead of closing them, as
is commonly, the result of artificial drying. In packing the timber on the
carriages or trucks care must be taken so as to arrange it as to allow a free
circulation of steam through the load, and in general it will be well to assort
the timber so that different thicknesses shall not be piled together. The

page_text: timber may be thoroughly seasoned from sixteen to forty-eight hours, depending
on the thickness. As a guide, it may be stated that inch pine boards can be
seasoned in from sixteen to twenty-four hours. When green timber is sub-
mitted to the action of the superheated steam its sap will give off steam in
large quantities, and so soon as there is an excess it will be discharged through
the porous bed of sawdust, or through a self-acting valve, and leave an
atmosphere that will act as a rapid heat transmitter, as above described.
When, however, the steam decreases, while then in a high heat, it is evidence
that the timber is nearly dry, the fire must then be diminished. As à modi-
fication of this self-acting outlet for the excess of vapour within the heating
chamber pipes may be used leading from the chamber, and their other ends
dipping into a water tank. Instead of the furnace and flues serpentine pipes
supplied with high-pressure steam may be disposed over the floor of the kiln,
and used for maintaining the atmosphere of superheated steam in the drying
chamber. By the means above described it is proposed to dry all kinds of
grain and fruits, and also animal and other substances that can be conveniently
subjected to heat in a drying chamber. In some cases shelves and other
supports will be required for supporting the articles to be treated, but timber
being one of the most important substances to be treated it has been used
in the above description as an illustration of the working of the Invention.
It will be, of course, understood that care must be taken to regulate the heat
of the furnace to suit the substances under treatment, and this can be done
by the aid of a thermometer inserted in the chamber, and visible from the
outside.
Having now set forth the nature of the Invention, and the manner of
carrying the same into effect, I would further remark, that as the Invention
relates to the treatment of a large variety of materials, and as no definite and
precise rules can be laid down to guide the operator in relation to temperature,
pressure of steam to be used, and duration of the operation, I have thought it
desirable to import into this my Specification the practical remarks of the
Inventor, as by that means an amount of knowledge will be imparted that
might otherwise require considerable experience to attain.
In using the superheated steam no more steam will be required than will
suffice to ensure during the operation a steam atmosphere in the drying
chamber, whether this steam atmosphere is or may be produced from the
drying substance or not. I will be recollected that we cannot see steam in
this drying room, for when there is the right amount of steam and it is
properly heated you could tell the time by the watch at a greater distance in
this steam atmosphere than if it were an air atmosphere; but you can feel

page_text: this steam atmosphere,, for its feel is like that of the Russian bath, for it will
make you perspire freely if you go in, or by holding your hand in you can at
once ascertain whether there is the proper steam atmosphere by the moisture
from your hand. The sawdust top (which should be the only exit for the
steam when in excess, as when made from the drying substance) should be of
just such a thickness as will balance a steam atmosphere in the kiln, so as to
exclude the air from the kiln, and take the place of air in conveying caloric,
and also to pass off all surplus steam, such as is being evolved constantly
from the drying substances. By this means it will be perceived that no heat
can be wasted, or pass out of the kiln, except it pass out in the steam
generated from the drying substance, which heat and steam it is very
important to have pass out as rapidly as possible, and still never deprive the
drying chamber of its steam atmosphere. There is only another way in which
heat can be wasted (if the kiln is built tight, according to the Specification),
and that is through the smoke pipe into the chimney. This can be avoided
by a long smoke pipe, and as long as will only allow so much heat to reach
the chimney as will insure a draft to the stove or heater...The smoke pipe
should not be less than twelve inches in diameter and a twelve-inch smoke
pipe has been found to be the best size. The value of the process will
also be seen in the ease, certainty, and economy with which the heat can be
regulated to adapt it to any degree for drying or seasoning of substances
requiring different degrees of heat in a more or less dense steam atmosphere.
A few experiments with any kind of substance will determine the best degree
of heat for that particular substance, and when ascertained that degree of
heat can be generated and maintained. As no two kilns can be built
precisely alike, so each kiln will have to be tested as to the best degree of
heat or the density of steam atmosphere for the different kinds. of. substances,-
though the general directions will answer for all properly constructed kilns.
Hard wood lumber should have a little more dense steam atmosphere than is
absolutely necessary for soft wood lumber, since hard wood is more liable to
close its pores on the outside before the inside is dry. I will also remark here
that one of the greatest defects in drying hard wood is the overdrying. The
shrinking of all kinds of lumber ceases by this process before it is bone dry.
If, therefore, the drying is extended much beyond this point it will open holes
in the centre of the lumber, while the openings will not be visible on the
outside. If openings shew themselves on the outside of the lumber it indicates
that there was not quite steam enough retained in the kiln to prevent forming
an enamel on the outside, as by the air. If openings are in the inside it shews
the lumber was overdried.

page_text: This process is therefore subject to complete control. You may either use
it with a very high degree of heat for rapid drying (or even melting of iron),
or with a corresponding degree of heat for drying of those delicate substances
which require a peculiar heat, while at all times the deleterious effects of
charing and other difficulties so common to an air atmosphere will be in a
great measure avoided.
Under the above in part recited Letters Patent I claim, kiln-drying timber,
grain, and other marketable products by using an atmosphere of steam in a
closed chamber so constructed as to allow of the discharge of any excess of
steam, and thus to limit the pressure, such steam being for the purpose of
transmitting caloric to the substance under treatment, as above described.
In witness whereof, I, the said Alfred Vincent Newton, have hereunto
set my hand and seal, the Seventeenth day of February, in the year of
our Lord One thousand eight hundred and sixty-six.
Witness,
J, W. MOFFATT,
66, Chancery Lane...
A. V. NEWTON. (L.S.)