CERTAIN NEW AND USEFUL IMPROVEMENTS IN APPARATUS FOR TREATING WOOD
Year: 1877

page_text: LETTERS PATENT to Edward Reynolds Andrews, of Boston, County of Suffolk,
State of Massachusetts, United States of America, for the Invention of
"CERTAIN NEW AND USEFUL IMPROVEMENTS IN APPARATUS FOR TREATING
WOOD." A communication by Ira Hayford, of Boston, County of Suffolk,
State of Massachusetts, United States of America.
Sealed the 30th November 1877, and dated the 6th October 1877.
COMPLETE SPECIFICATION filed by the said Edward Reynolds Andrews at
the Office of the Commissioners of Patents on the 6th October 1877.
"
EDWARD REYNOLDS ANDREWS, of Boston, County of Suffolk, State of Massa-
chusetts, United States of America. CERTAIN NEW AND USEFUL IMPROVEMENTS
A communication by Ira Hayford, of
IN APPARATUS FOR TREATING WOOD."
Boston, County of Suffolk, State of Massachusetts, United States of America.
In my present apparatus I employ a reservoir or chamber for receiving and
treating wood, a tank or vessel for containing the chemical substances or fluids
with which the wood is to be charged, and an air pump, which becomes alternately
à vacuum pump, to extract the vapors from the wood-preserving chamber, and the
agent for forcing the treating fluids into the wood-receiving chamber. Steam from
a suitable source is employed in connection with the above, and the whole operating
substantially as herein-after explained.
The apparatus is provided with means for creating a vacuum in said chamber
after saturation of the wood by the steam, and the withdrawal of the vapors of the
latter, in order that the pores and cells of the wood may be distended and readily
absorb the preserving agent, and with means for continuously re-introducing the
preserving agent to the preserving chamber until the wood becomes saturated to
the desired extent, together with means for enveloping the wood at the same tinie
in a jacket of air to avoid checking and splitting. -
The Drawings accompanying this Specification represent in Figure 1 a plan,
in Figure 2 an end elevation, in Figure 3 a horizontal section, and in Figure 4 a
cross section of an apparatus embodying my improvements.
Figure 5 is an elevation of the front portion of the preserving retort, with the
pipes connected therewith,
--

page_text: In these Drawings A represents a steam boiler, from which I obtain steam
employed in the apparatus, while B represents the closed cylinder or tank to contain
the creosote or other material with which the wood is to be charged; and J, a
second tank or recevoir, which constitutes the chamber in which the wood is
treated, the latter being provided at one or both ends with a door, by which the
wood is introduced into the interior. K represents an air pump, disposed immedi-
ately adjacent to the tanks A & B, and constructed with an annular water chamber L,
surrounding its air cylinder, to contain a quantity of water and keep the interior of
the cylinder cool, the steam cylinder and piston of this pump being shown at
M & N respectively, and the air cylinder and piston at O & P. Suitable inlet
and outlet pipes and cocks are combined with the water chamber L, by which water
from a suitable source is allowed to circulate through said chamber, and thereby
maintain a low temperature within the cylinder to counteract the heat resulting
from the compression of the air in the latter, and of the vapors issuing therefrom.
Each end of the air cylinder O communicates with a bent pipe Q or Q', the outlet
O2 and P2 of each pipe being provided with a cock 12 or 13, by which air may be
allowed to enter the cylinder, while the two pipes between the cocks and cylinder
are united by and communicate with a shaped pipe C, the upright portion of
this pipe being provided with a cock 10, and extending by a horizontal portion C+
into the wood-preserving chamber J.
When the cocks 12 and 13 are closed, and the pump is in operation, a powerful
,draft or suction takes place through the pipes Q, Q1, & C from the chamber J into
the air cylinder O of the pump, and exhausts through a pipe D leading from said
cylinder. This exhaust pipe extends vertically from the pump cylinder, and
continues by a horizontal portion D³, the outlet of the latter being furnished with a
cock 11. From the horizontal portion Do of the pipe D rises a continuation or pro-
longation in the form of a bent pipe Do, the upright part of which is furnished with
a cock 9, while the horizontal portion extends over the chamber J downward in
rear of it, and communicates with the barrel R of an injector R', while a branch
pipe De of the horizontal portion D³ of the pipe D extends into and communicates
with the interior of the wood-preserving chamber J, the upright portion of said
pipe D, in rear of said chamber J, being provided with a cock 21, and the pipe Do
being furnished with a cock 8. The barrel R is contracted at its outlet, as shown
at S, and is prolonged into a bent pipe H, which extends upward and over the
chamber J, thence downward into the latter by an upright portion H³, and
terminates within said chamber J in one or more open or foraminous branches
T, T, etc., the said upright part H³ having a cock 17, while its upper horizontal
part has a cock 18.
The upright portion H2 of the pipe H rises above and extends
horizontally by a portion E over the branch H³, and is provided with a cock 16,
such portion E¹ extending downward, and entering and communicating with the
lower part of the interior of the tank B.
A steam conduit I leads from the boiler A into the lower part of the chamber J,
and is provided with a cock 7, and after describing several turns or coils within the
chamber J to obtain a large heat radiating surface, it makes its exit from such
chamber by a horizontal portion Ụ, which at its extremity is open to the
atmosphere and furnished with a cock 4. Between the cock 4 and the chamber J
the horizontal portion U of the pipe I is continued upward by an extension V, and
enters and communicates with the upper part of the interior of said chamber J, and
is provided outside of the chamber with a cock 3. The steam conduit I has a
branch or extension 2, which enters the valve chamber W of the steam cylinder of
the pump K, and is furnished with a cock 1, while the main part of the conduit I
near to the boiler is provided with a cock 1/4.
Furthermore the steam conduit I has a second extension or branch X, which
extends to and enters the tank B, and after coursing about the interior of the
latter, makes its exit therefrom and discharges into the atmosphere except when
closed by a cock 22 which is attached to it.
From the barrel R of the injector R¹: and communicating with its interior.

page_text: extends a horizontal pipe F, which is furnished close to the barrel with a check
valve Y opening towards said barrel, and with a cock 19 outside of such check
valve, such pipe F extending upwards into and communicating with the interior of
said chamber J by an upright branch Z, which is furnished with a cock 5, while the
5 horizontal part of such pipe F joins and communicates with the horizontal pipe H",
one end of which is open to the atmosphere except when closed by cock 6 applied
to it, while its other end is continued upward by an extension F, and enters the
upper part of the interior of the tank B. A branch pipe D' connects at one end
with the pipe D³, and at the other end with the interior of the tank B, and is
furnished with a cock 14.
The operation of this apparatus is as follows:-Supposing steam to be up in the
boiler, a proper quantity of creosote or other preserving fluid placed in the tank B,
and the desired quantity of wood to be treated placed within the chamber J, and
the doors of the latter closed, the cocks ¼¼ 3, 5, 6, 7, 8, 9, 12 and 13
being open, and all the rest herein-before named shut, with the exception of
those applied to the circulating pipe of the water-chamber of the pump cylinder,
which of course are always open when the apparatus is in operation, steam
from the boiler passes through pipe I into the interior of the chamber J,
and acting upon the wood serves to soften the latter and expand its pores and
vaporize the sap, which then escapes, while at the same time air is driven from the
air cylinder of the pump through the pipe D, D5, D, etc., into the interior of the
chamber J, with greater or less pressure, and by surrounding the wood prevents
à vacuum (which would otherwise result from the condensation of steam) and thus
prevents cracking or checking of such wood. This having been continued for a
proper length of time, I now close all approach to the chamber J except through
the steam heating coil, which I do by closing the cocks 8, 9, and 3, the steam thus
circulating through the coil in the chamber J, and exhausting by the cock or outlet
4. The heat radiating from the coil serves to thoroughly dry the wood.
Simultaneously with the closing of the cocks 8, 9, and 3, and the shutting
out of the entrance of steam directly into the interior of the chamber J,
the cocks 10 and 11 are opened, and 12 & 13 closed, consequently the
pump is converted from a pressure to a suction or
the vapours resulting from steam, and the heat within the chamber J, are
vacuum pump, and
withdrawn from such chamber by means of pipe C, and exhausted through the cock
11. This continues until the vapors cease to issue from the cock 11 (it being
observed that the water-jacket of the air cylinder of the pump serves at this time
to reduce the temperature of such vapors) when the cock 10, which, as will be
seen, constitutes the means of communication between the air-pump and treating-
chamber J through pipe C, is shut, by this means closing such communication, and
the exhaust cock 11 is also closed.
I now open cocks 12 and 13, which permits inlet of air to the pump cylinder, and
also open cocks 9 and 14 (it being understood that said pump is continually in
operation) by which means air is forced by the pump through pipe D, D³, D', etc.,
through the cock 14 into the creosote tank B, it being borne in mind that the cock
8 is at this time closed. The air entering the tank B under pressure from the
pump, as last atated, drives the creosote or other preserving fluid from such tank
into the chamber J, and forces the fluid into the pores and cells of the wood, which
are distended and open from the action of the steam, the fluid in its passage to the
chamber J passing through pipe E and cocks 16 & 17, which are opened for the
first time to permit this.
As soon as the preserving fluid in the tank B has been driven from it in the
manner last stated, I close the cock 14, which shuts off pressure of air from the
pump to such tank, and also shut cock 16, which closes communication between the
tank B and chamber J by way of the pipe E. I next open cock 21 in the exten-
sion D of the pipe D³, which permits air under pressure from the pump through
pipe D, D, D, etc., to enter and course through the injector barrel R, where it
unites with the excess of fluid flowing from the bottom of chamber J through pipe F

page_text: by opening cocks 5 & 19, and carries it with it in its course through pipe H,
cocks 18 & 17 being open, back into the foraminous pipes within chamber J, and
thus forces the fluid into the wood, this circulation being continued under pressure
until the wood has taken up all the creosote or other preserving agent, or so much
thereof, as may be found desirable.
When the pores and cells of the wood have absorbed all the treating material
which it is capable of receiving, predestined quantity, whatever it may be, the
air pump is stopped, cocks 17, 18, 19, & 21, which open the communication with
the air injector R¹ are closed, and cock 20 in pipe H, Fu, opened, consequently any
excess of creosote remaining in the chamber J not taken up by the wood is forced
back to the tank B by the pressure remaining in the chamber.
The chamber J is now allowed to cool down, the cock 20 is closed, and the wood
perfectly treated taken from such chamber. In this process of treating wood, and
the necessary apparatus heretofore described for the purpose, it will be observed that
I employ steam at such temperature as is necessary for a certain length of time for
the purpose of softening the fibres of the wood and opening the cells and pores
thereof, and vaporizing the sap and fluids contained therein, thus preparing the
wood for the entrance of the preserving fluid and a complete saturation of its tissues
by the same.
Moreover steam alone would cause the wood to crack and check from the expan-
sion caused by the heat generated in the interior of the wood, which heat is
necessary to effect the evaporation of the sap. Hence I force into the preserving
chamber the necessary pressure of atmospheric air to prevent the wood from
checking.
Wood cannot be thoroughly impregnated with creosote or other preserving fluids
until the sap or water is drawn out of the pores of the wood; hence the methods
above described are essential for that purpose.
In this process, while using air under pressure sufficient to prevent the wood from
cracking, I exhaust the vapors through a vacuum pump, as described, maintaining
the necessary degree of heat to prevent condensation by means of the coil of steam
pipe in the bottom of the preserving chamber.
In withdrawing the vapors in the manner described, I also create a vacuum
around the wood being treated, a condition favorable for its complete impregnation
by the preserving fluid, which is sucked into the dry hot pores and cells, and forced
into the wood by the high atmospheric pressure used.
My method of introducing the preserving fluid into the treating chamber through
foraminous pipes, so arranged as to shower upon the wood from every direction,
and afterwards, by means of an injector, as described, keeping up a continuous circu-
lation of the preserving fluid, is superior to any method for soaking wood in a vat,
the fluid entering the wood more thoroughly, and ensuring a perfect saturation of
the wood.
Having thus described the nature, purposes, and advantages of my Invention,
and the manner in which the same is or may be carried into effect, what I claim
as of my Invention is as follows:-
1st. An apparatus for preserving wood, consisting in general of the steam
generator A, or other source of steam supply; the tank B, for containing a supply of
preserving material; the tank or chamber J, for receiving the wood while under-
going the preserving process; and the pump K; such elements of this apparatus being
provided with the system of pipes and cocks, as herein explained, and the whole
operating essentially as stated.
2nd. The combination with the chamber or retort J of the air pump K with
connecting pipes and cocks, arranged substantially as herein stated, so that the sap.
and moisture contained in the wood may be completely withdrawn from the wood
by the steam, and the vapors of the latter may be withdrawn from the chamber and
, a vacuum created therein, substantially as and for purposes stated.
3rd. The combination with the chamber J of the air pump with connecting pipes
and cocks arranged substantially as stated, so that after the saturation of the wood

page_text: and complete withdrawal of the vapors of the latter, the wood is surrounded by a
vacuum, essentially as stated.
4th. An air pump having its air cylinder surrounded totally or in part with &
water chamber to reduce the temperature of the interior, substantially as and for
purposes stated.
5th. The combination with the air pump K, and chamber or retort J, of the two
systems of pipes D, D³, etc., and Q, Q, Q, etc., with their respective cocks, sub-
stantially as herein shown, whereby such pump becomes at one time a force pump,
to drive air into the treating chamber J, at another time a vacuum pump, to extract
vapors from such chamber and create a vacuum therein, and at another time a force
pump, to drive the treating fluid from its reservoir into the treating chamber and
the pores of the wood, and finally, a force pump, to maintain a circulation of air and
of the preserving fluid throughout the preserving process, substantially as and for
purposes stated.
6th. The system of treating wood to preserve the same by admitting to the retort
in which the preserving process takes place, a combined current of air and preserving
fluid under pressure, essentially as and for purposes stated.
7th. The injector RI and air pipe or conduit D in combination with the
chamber or retort J, tank B, and air pump K, substantially as and for purposes
stated.
8th. The injector R³, as composed of the barrel R, and air pipe D", and connected
with the retort B or other reservoir or source of liquid supply, essentially as and for
purposes stated.
In witness whereof, I, the said Edward Reynolds Andrews, have hereunto set
my hand and seal, this Twenty-first day of September, One thousand eight
hundred and seventy-seven.
Witnesses,
L. A. CURTIS.
F. CURTIS.
EDWARD REYNOLDS ANDREWS. (L.S.)