Improvements in Furnaces or Kilns for Burning Bone Black.
Year: 1889

page_text: Date of Application, 30th July, 1889-Accepted, 16th Nov., 1889
COMPLETE SPECIFICATION.
Improvements in Furnaces or Kilns for Burning Bone Black.
I ADAM WEBER Manufacturer of 633 E 15th Street in the City County and State
of New York United States of America 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 :-
This invention has reference to an improved furnace or kiln for burning bone
black which kiln is constructed on the regenerative system and heated by means of
gas generated in a separate furnace and in which the raw hones are fed automatically
by gravity from stationary hoppers to the retorts of the kiln while the burned bones
are gradually discharged from the coolers below the retorts into a conveyer by which
the burned bones are conducted to a suitable well and then lifted by an elevator into
hoppers from which they are conducted to grinding mills in which the bones are
ground to bone black of different degrees of fineness for the market.
The object of this invention is to facilitate the working of my improved bone black
kiln in such a manner that the hand labour required for running the kiln is to a
great extent dispensed with as the supply of raw bones to the retorts and the removal
of the burned bones from the retorts is accomplished by gravity and intermittently
operated power driven mechanism and the invention consists firstly of the arrangement
of rows of retorts in the combustion chamber of the kiln which retorts are braced
at their inner ends by transverse arched saddle tiles resting on projections of the
retorts sideways by abutting projections and at the outer ends by vertical division
blocks so that the retorts are supported in a stronger and more durable manner and
rendered more capable of resisting the bulging and cracking tendency to which they
are subjected by the high temperature in the combustion chamber.
The invention consists secondly of a gravity feed by which the raw bones are
supplied from stationary hoopers to the retorts and from the same to the coolers
below the retorts which coolers are provided with sliding dampers guided in ways at
their lower ends and with discharge spouts below said dampers.
The invention consists thirdly of the combination of the retorts having partitioned
mouth pieces and connecting pipes with hydraulic mains in which the liquid products
of distillation are separated from the gaseous ones said hydraulic mains being
connected by pipes with a saturator and the latter by return pipes with supply
channels in the throat of the gas generating furnace said return pipes conducting the
gaseous products of distillation back to the furnace for combustion.
The invention consists fourthly of the combination with the retorts and coolers
located below the same of sliding dampers and inclined discharge spouts below said
dampers of intermittently actuated mechanism by which the sliding dampers below
the coolers are operated so as to discharge the burned bones into a spiral conveyer
arranged in a trough below the coolers by which conveyer they are conducted forward
to an elevator from which the burned bones are carried up into a suitable hopper from
which they are supplied to the grinding mills. The invention consists lastly of certain
details in the construction of the kiln and of the flues of the same and in certain
constructive details by which the sliding dampers are intermittently operated as will
be fully described hereinafter and finally pointed out in the claims.
In the accompanying drawings Figure 1 represents a side elevation partly in
vertical longitudinal section of my improved bone black kiln showing two coolers
arranged back to back and the gas-generating furnaces for supplying them
with gaseous fuel also the supply hoppers for the raw bones and the conveyer for
the burned bones.
Figure 2 is a vertical transverse section of my improved bone black kiln showing
the elevator for supplying the raw bones to the supply hoppers and the supply pipes
for feeding the same to the retorts.

page_text: Figure 3 is a side elevation of one kiln and its gas generating furnace drawn on a
larger scale.
Figure 4 is a vertical longitudinal section of the kiln and its generating furnace on
line a Figures 6 and 7.
Figure 5 is a vertical transverse section of the kiln on line y y Figure 6.
Figures 6 and 7 are horizontal sections respectively on lines Figure 4 and k k
Figure 5.
Figure & represents a vertical central section and Figure 9 a horizontal section-on
lines and y y¹ Figure 8-of two coolers and the mechanism by which the sliding
dampers of the same are intermittently operated and
Figure 10 represents an end view of the coolers and their damper operating
mechanism the last three figures being drawn on a still larger scale.
Similar letters of reference indicate corresponding parts.
My improved bone black kiln consists of two main parts a gas generating furnace A
and a kiln B proper the former being arranged in front of and with its greater part
below the level of the bottom of the furnace or kiln B. In the kiln B are arranged
one or more rows or benches of vertical retorts CC. An arched central combustion
chamber B' extends longitudinally between the retorts through the kiln B. The gas
generating furnace may be of any approved construction it being advantageously
provided at its base with a grate and a step shaped fire pot and at the top with an
opening closed by a cover through which opening the fuel is supplied at regular
intervals. The upper part of the gas generating furnace A is connected by a
rearwardly extending channel or throat a with the lower part of the furnace or
kiln B the channel a being provided in its side walls with lateral channels a' through
which the highly heated air is introduced so as to be mingled with the carbonic
oxide gas produced in the gas generating furnace A. The air is drawn in at the
sides and near the base of the gas generating furnace A and heated by being passed
through a system of zig-zag flues that are located in the side walls of the gas
generating furnace A and connected at their upper ends with the lateral channels a¹
in the side walls of the channel or throat a. The construction of the gas generating
furnace and the arrangement of the air heating flues in the same are well known and
form no part of the present invention.
The bone black retorts C C are made of refractory material and supported on a
bottom which is made of cast iron sections or plates C that are supported like the
side walls of the furnace on double T-beams placed on upright columns. The retorts
are of oval shape and provided at the inner ends and sides with projections d'
which are made integral with the retorts the projections at the sides being made
to alternate with each other and abut against the projections of the adjoining retorts.
The projections & serve for keeping the retorts at the proper distance from each
other so as to permit the fire gases to pass freely between the same. The projections d
at the inner ends of the retorts serve for supporting arched transverse saddle tiles C
which act like braces on the retorts and prevent the bulging and cracking of the
same while they are exposed in charged condition to the heat of the kiln. The lower
ends of the retorts C are supported in sockets or flanges which are cast integral
with the bottom plates C the lower ends of the retorts being set on and packed by
suitable fluxing material so as to produce the air tight connection between the
sockets and the retorts C. The bottom plates C are protected at their upper
surface with one or more layers of refractory material so as to prevent the radiation
of heat to the outside. The opposite ends of the retorts C are supported along their
whole length by division blocks C³ the edges of which abut against the retorts as
shown in Figure 7. The lower ends of the division blocks C3 are supported near
the bottom of the kiln B' on inwardly projecting tiles e e built into the side walls of
the kiln B¹ as shown in Figure 5. Between the division blocks (³ vertical flues C¹
are formed through which the hot products of combustion are drawn up the lower
ends of said flues" communicating near the bottom of the kiln with the spaces below
the tiles e e. The fire gases are drawn from the arched top of the combustion
chamber downwardly in a diagonal direction between the retorts to the spaces below

page_text: the tiles e and into the lower ends of the flue (as shown by arrows in Figure 5.
The fire gases are then drawn up in the flues C along the ends of the retorts so as
to heat the entire surface of the retorts from the bottom to the top in a uniform
manner. From the upright flues C₁ the gases pass through lateral side flues C³ into
main flues C provided with sliding dampers C7 so as to regulate the draft and
subject thereby all the retorts to a uniform degree of beat. For this purpose the
dampers at the front of the kiln are partly closed while the dampers farther back in
the kiln are opened to a greater extent. The gases are conducted from the main
flues to the chimneys (which latter are also provided with dampers C which
serve to regulate the heat in the kiln after the temperature of the kiln has been raised
to the required degree and regulated by means of the lower dampers.
The retorts next adjoining the front and rear walls of the kiln abut by their
lugs against lugs in said walls which lugs serve in connection with the side
lugs d' of the retorts the saddle tiles C and the vertical division blocks C³ to support
all the retorts firmly and reliably in the kiln.
By thus supporting the retorts on all sides they last for a longer period of time
while the fire gases are permitted to lap around all the sides of the retorts by which
they are kept at uniform heat over their whole surface and prevented from warping
or cracking by the influence of the high degree of temperature to which they are
subjected. Large injurious cracks are thus prevented while the smaller cracks can
be readily closed by suitable fluxing material without stopping the operation of
the kiln.
The upper ends of the retorts are provided with cast iron mouth pieces D which
are closed by covers D' that are tightly bolted thereto. The covers D communicate
by means of cast iron sockets D² with feed pipes D³ which are connected with bottom
openings of stationary supply hoppers F that are located above the kiln. The crushed
raw bones are charged into the supply hoppers by means of a suitable elevator E¹
shown in Figure 2 and are gradually fed by gravity to the retorts. The supply
openings of the hoppers E are provided with supply regulating slides f by which the
hoppers can be entirely closed off from the conducting pipes whenever the supply of
bones is to be interrupted for the purpose of making repairs. The hoppers E are
made of boiler iron and of sufficient height so that the pressure of the bones in the
same will overcome the upward pressure of the gases of distillation generated in the
retorts. The covers D₁ of the retorts are further provided with small eye holes
through which the condition of the change in the retorts can be observed. These holes
are closed by tightly fitting plugs f¹ so as to prevent the air from entering at the
mouth pieces of the retorts.
The
To the bottom plate of the kiln B vertically below the retorts are attached cast iron
extensions or coolers D which are flanged at their upper ends and bolted in an
air tight manner to the underside of the cast iron bottom plates C. The lower ends
of the coolers D₁ are provided with bottom openings and with sliding dampers C³
having openings registering with the bottom openings of the coolers D).
dampers D slide in air tight guide ways at the lower ends of the coolers D' so that
the access of air is entirely prevented and thereby the charges of bone black in the
kiln prevented from being injured. This is absolutely necessary as the gases of
distillation in the retorts are drawn off by means of an exhauster which requires that
all the joints between the retorts and the kiln and between the coolers and the bottom
plates and between the lower ends of the coolers and the dampers D³ have to be
absolutely air tight for producing the proper and reliable working of the retorts.
The dampers at the lower ends of the coolers are operated automatically by suitable
mechanisin so as to discharge the bone black in small quantities at suitable intervals
of time. As soon as a quantity of burned bones is discharged at the lower ends of
the coolers a corresponding quantity of raw bones is fed through the feed pipes D³
into the upper ends of the retorts and in this manner the desired intermittent feed
is kept up by gravity.
The mouth pieces D of the retorts are provided with transverse partition walls g
which are bolted on to the covers D' so as to form spaces g¹ at one side of the same

page_text: into which the gases of distillation are drawn said partition walls serving to prevent
the bones from filling up these spaces. The spaces y are connected by downwardly
inclined tubes g² with vertical pipes g³ which are connected to hydraulic mains F of
which one is arranged at each side of the kiln B and supported on suitable frame
work. The heavy liquid products of distillation such as tar etc. are collected in the
hydraulic main while the gaseous products are drawn off from the same by an
exhauster through pipes F¹ to a condenser and saturator (not shown in the drawings)
in which latter the remaining liquid products of distillation aro separated from the
gaseous products the latter being reconducted by pipes F2 and lateral supply
channels located in the side walls of the gas channel or throat a into the kiln as
shown clearly in Figures 14 and 5. This separation and reconducting of the
combustible gases of distillation and the utilization of the same in the furnace forms
another advantageous feature of my present invention and adds thereby to the
economic results obtained in working the kiln. The return gases of distillation
mingle in the gas channel or throat a with the gases generated in the furnace A and
are burned with the same so as to be utilized in heating the retorts. The tar obtained
from the hydraulic mains condensers and saturator is also burned in the furnace by
being introduced by a suitable hydrocarbon injector of any approved construction
in the form of a spray inio the gas generating furnace so that the quantity of fuel
required for heating the kiln is considerably reduced and a large saving in fuel
obtained. Only a small quantity of fuel is required to be burned in the gras
generating furnace which fuel is kept at incandesence and which is sufficient for
igniting the gaseous products of distillation and the tar fed into the furnace.
The lower ends of the coolers D₁ are provided below the sliding dampers D' with
inclined converging discharge spouts D which communicate with the casing of a
spiral or other conveyer G₁ arranged in a longitudinal trough G. The openings of the
coolers D and dampers D are alternately placed in and out of register by mechanism
which imparts intermittent reciprocating motion to the dampers. The outer ends of
the sliding dampers D' are provided with anti-friction rollers which are engaged by
grooves arranged at both sides of the cam wheels as shown in Figures S and 9.
The cam wheels are keyed to a shaft S which extends longitudinally between the
lower ends of the coolers and to which a continuous rotary motion is imparted by a
chain and sprocket wheel transmission or by any other transmitting mechanism from
a power shaft S shown in Figure 2. The cam grooves of the cam wheels W are
provided with eccentric portions which are so arranged that when the anti-friction
rollers pass into said eccentric portions the openings of the dampers D are quickly
moved into register with the discharge openings in the bottoms of the coolers while
when the rollers move along the concentric portions of the cam grooves the
openings of the dampers are moved out of register with the bottom openings of the
coolers and produce thereby the closing of the coolers. The cam wheels W are so
arranged between the coolers that each cam wheel operates the sliding dampers of
two adjoining coolers located at opposite sides of the shaft S one half of the
rotation of the cam wheel W opening the damper of one cooler while the other half
rotation opens the damper of the adjoining coolers as shown clearly in Figures 8
and 9. The cam wheels W are located in different relative positions on the shaft S
so that the sliding dampers of one row of coolers are not operated at the same time
but in succession to each other and alternately with the dampers of the adjoining
coolers. This is accomplished by attaching the cam wheels W to the shaft in such
a manner that the eccentric portions of the cam grooves are not in line with each
other but at different angles to the axis so that by one entire rotation of the shaft S
all the dampers of both rows of coolers are successively opened and closed one after
the other and at regular intervals of time. The discharge of the burned bones from
the coolers is thereby so timed that the contents of the coolers are gradually dis-
charged. The size of the openings in the bottoms of the coolers and in the sliding
dampers as well as the length of time during which the openings register with each
other are so proportioned that the full charge of the retorts is drawn off every four
hours so that consequently 240 revolutions of the cam wheels, are required for

page_text: drawing off a full charge from the retorts. It appears thus that a comparatively
small quantity of burned bones is drawn off at each reciprocating motion of a damper
so that the downward motion of the bones in the coolers and retorts and the feed of
the raw bones from the hoppers to the retorts is slow gradual and uniform taking
place intermittently but without sudden jerks and drops. As one damper after the
other is opened the exhaust by which the gases are drawn off from the retorts is
not injuriously affected and thereby the interior of the retorts and coolers retained
at a uniform pressure.
The casing or shell of the conveyer G₁ may be cooled with cold water which is
admitted into the trough G. The bones are conveyed forward and dropped into the
well of an elevator H shown in Figure 1 by the buckets of which they are lifted into
a hopper (not shown in the drawings) from which they are supplied to the grinding
mills for being ground to the proper degree of fineness as required for the different
purposes for which they are used.
The slow discharge of the burned bones from the coolers at regular but short
intervals of time has the following advantages; first of keeping up a uniform and
regular motion of the bones through the retorts and coolers secondly of not over-
loading the conveyer and elevators thirdly of not interfering with the regular
exhaust which is kept uniform and without being liable to sudden variations and
fourthly of keeping up a uniform heat in the kiln as the retorts are not chilled by
the cold raw bones charged into the same. The running of the bone kiln is accom-
plished with great facility as the feeding of the raw bones to the retorts the burning
of the same while passing through the same the dropping of the burned bones from
the coolers the conveying off of the burned bones and the drawing off of the
utilizable gases from the retorts take place with the utmost precision and reliability
and without any stops or interruptions so that the bones are not only burned in a
more satisfactory manner but also an increased yield of bye products obtained as
compared with the bone black kilns in which the retorts and coolers are intermittently
discharged by hand labour.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. In a bone black kiln the combination with rows or benches of retorts arranged
in the same said retorts being provided with projecting lugs at the sides and inner
ends of transverse saddle tiles resting on the inner lugs and vertical division blocks
abutting against the opposite ends of the retorts substantially as set forth.
2. In a bone black kiln the combination of the combustion chamber rows or benches
of retorts in the same vertical division blocks abutting against the ends of the retorts
projecting tiles near the bottom of the kiln for supporting said blocks flues formed
below said blocks flues formed between the ends of the retorts and the division
blocks and flues located in the side walls of the kiln and communicating with the
flues between the division blocks substantially as set forth.
3. In a bone black kiln the combination of the combustion chamber rows of retorts
in the same said retorts having abutting side lugs and transverse saddle tiles resting
on lugs at the inner ends of the retorts substantially as set forth.
4. The combination of a bone black furnace or kiln having cast metal bottom plates
provided with sockets or flanges integral therewith retorts supported in said sockets
supply hoppers supported above the kiln inclined feed pipes connecting the bottom of
the hoppers with the heads of the retorts regulating slides for said feed pipes and
coolers located vertically below the retorts and provided with dampers at their lower
ends substantially as set forth.
5. The combination in a bone black furnace or kiln of a series of retorts located in
the same mouth pieces at the upper ends of the retorts provided with transverse
partitions forming spaces at one side thereof inclined pipes communicating with
said spaces and hydraulic mains connected with said pipes substantially as set forth.
6. The combination with a bone black furnace or kiln provided with cast iron

page_text: bottom plates having sockets or flanges made integral therewith retorts located in the
kiln and supported in said sockets coolers bolted to the underside of the bottom
plates in line with the retorts and sliding dampers at the lower ends of the coolers
substantially as set forth.
7. The combination with a bone black furnace or kiln of rows of retorts located in
the same a gas generating furnace located in front of the kiln and provided with a
contracted channel or throat hydraulic mains located at both sides of the kiln tubes
for connecting the mouth pieces of the retorts with the said hydraulic main pipes
leading from the bydraulic mains to a saturator and gas return pipes leading from
the saturator to the kiln and connecting with supply channels in the throat of the
gas generating furnace substantially as set forth.
8. The combination of a bone black kiln rows of retorts located in the same supply
hoppers above said kiln feed pipes connecting the supply hoppers with the mouth
pieces of the retorts coolers below the retorts converging discharge spouts below the
coolers intermittently reciprocating dampers between the coolers and discharge
spouts and a longitudinal conveyer below said discharge pipes substantially as set
forth.
9. The combination in a bone black kiln of rows of retorts coolers located below
the retorts converging discharge spouts below said coolers sliding dampers between
the coolers and discharge spouts and mechanism for imparting intermittently
reciprocating motion to said dampers substantially as set forth.
10. The combination in a bone black kiln of rows of retorts coolers below said
retorts converging discharge spouts below said coolers sliding dampers between the
coolers and discharge spouts and rotary cam wheels having eccentric grooves
for engaging said dampers and intermittently reciprocating the same substantially as
set forth.
11. The combination in a bone black kiln of rows of retorts coolers below said
retorts provided with bottoms having openings dampers having openings registering
with said bottom openings anti-friction rollers at the outer ends of the dampers cam
wheels provided with eccentric grooves for engaging said rollers a rotary shaft to
which said cam wheels are applied and mechanism for rotating said shaft so as to
intermittently operate the sliding dampors and discharge gradually the burned bones
from the retorts substantially as set forth.
12. In a bone black kiln tho combination of rows of retorts coolers located below
the retorts and provided with bottoms having openings converging discharge spouts
below said coolers dampers having openings registering with said bottom openings a
rotary shaft located intermediately between said coolers grooved cams attached to said
shaft and connected with the dampers and a rotary screw conveyer located below the
discharge spouts of the coolers substantially as set forth.
13. In a bone black kiln the combination of rows of retorts coolers located below
the retorts and provided with bottoms having openings registering with said bottom
openings converging discharge spouts below said dampers a rotary shaft located
intermediately between the coolers grooved cams on said shafts connected to said
dampers a rotary screw conveyer below the discharge spouts and a cooling trough
surrounding the conveyer substantially as set forth.
Dated this 30th day of July 1889
TONGUE & BIRKBECK,
34, Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Applicant.