Improvements in Heating Furnaces.
Year: 1897

page_text: Date of Application, 11th May, 1897-Accepted, 3rd July, 1897
COMPLETE SPECIFICATION.
Improvements in Heating Furnaces.
We, ALEXANDER LAUGHLIN, residing at Sewickley, and JOSEF REULEAUX,
residing at Wilkinsburg, both in the County of Allegheny, State of Pennsylvania,
and United States of America, Mechanical Engineers, 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.
The invention described herein relates to certain improvements in what are
known as continuous heating furnaces, i.e., furnaces in which the article is charged
into one end thereof and forced through and discharged through the opposite end,
being heated during its progress through the furnace.
These furnaces are of necessity, quite long, i.e., thirty or forty feet, and
are heated by the combustion of gas or the flame and products of
combustion of solid fuel, the heating medium being admitted to the
discharge end of the furnace. It is necessary for the efficient heating, that a long
flame approximately equal to the length of the furnace should be produced. This
is usually effected by increasing the draft of the stack at the front end of the
furnace. When side inlet flues are employed in connection with an increased
draft, the middle portions of the furnace near the rear or discharge end, are not
efficiently heated, as the flame is drawn away from such middle portion by the
increased draft, as the two lines or streams of flame are drawn at a sharp angle to
the direction of the flow of the gas and air from the ports and only unite at a
considerable distance from the rear end of the furnace. Gas and air have also
heen admitted through the roof of the furnace, the design being to project the flame
down on to the articles passing through the furnace. This method is objectionable
for the reason that the heating is, as it were, localized, the flame having a blow pipe
action, thereby injuriously heating the articles.
For the purpose of annealing, furnaces have been constructed with a long
chamber through which articles can be moved continuously. These furnaces have
been constructed with inlet flues arranged transversely of the heating chamber, so
that articles will pass over these flues in their movement through the chamber.
These flues are located either at the entrance end of the chamber or about midway
of its length or between these two points. It results from such a construction that
the articles as they move slowly through the furnace are highly heated before they
reach the middle of the furnace, and are cold when they are discharged. Such
construction is inapplicable to heating billets, which should be discharged when
heated to the highest degree.
The object of the present invention is to provide for the introduction of the gas
and air or products of combustion from the solid fuel, into the furnace below the
line of travel of movement of the article to be heated, and, in general terms, the
invention consists in the construction and combination substantially as hereinafter
more fully described and claimed.
In the accompanying drawings forming a part of this specification, Figure 1 is
a side elevation of my improved furnace; Fig. 2 is a longitudinal, vertical section

page_text: of the same; Fig. 3, a sectional plan view; Figs. 4 and 5 are sectional elevation
and plan, respectively, illustrating certain modifications in the supports for the
articles to be heated; Figs. 6, 7, 8 and 9, are views similar to Figs. 4 and 5, of
further modifications of the supports for the articles to be heated; Figs. 10 and 11
are vertical, transverse sections, the planes of section being indicated by
line X-X, XI-XI, Fig. 3; Fig. 12 is a sectional plan view of my improved
furnace, showing the arrangement of the combustion and heating chambers when
employing solid fuel; Fig. 13 is a sectional clevation, the plane of section being
indicated by line XIII—XIII, Fig. 12; Fig. 14 is a longitudinal vertical section
on the line XIV-XIV, Fig. 15, and Fig. 15 is a sectional plan view, said view
illustrating certain modifications in the manner of supports for the rails or pipes
on which the billets rest in their passage through the furnace.
In the practice of my invention, the furnace is constructed as regards the exterior
walls and the bed 1 thereof, in the usual or any suitable manner. Along the rear
end of the furnace are arranged the gas and air ports of flues 2 and 3, said ports
or flues extending transversely and across the furnace in proximity to the rear wall
thereof. The gas ports connect at their lower ends, with a transverse conduit 4,
which in turn connects with a supply conduit 5. The air ports or flues 3 are
connected with a horizontal conduit 6, 'through which air is conducted to said
ports. The flues or ports 2 and 3 are extended below their points of connection
with the air and gas supply conduits, such extensions communicating with
pockets 7, for the reception of slag or other material which would be liable to
choke up the gas and air flues, said pockets being provided with doors 8, through
which slag or other dirt can be removed from the pockets.
On bed 1 of the heating chamber are formed two or more main supports or
piers 9, extending longitudinally through the furnace from the front towards the
rear end thereof, preferably terminating in front of the bridge wall 10. It is
preferred to arrange on these continuous piers, a hard wearing surface 11, in the
form of a rail or tube, preferably the latter, through which water is caused to
circulate to prevent injury by the heating of the furnace. These wearing surfaces
or tubes preferably extend to the rear edge of the bridge wall, as shown in
Figs. 2 and 3. Provision is made for the automatic movement of the articles
being heated from the main supports 11 to the end discharge opening and
preferably across the flues 2 and 3. This automatic movement is preferably
effected by means of a series of inclined supplemental supports or bridge pieces 12,
which are preferably formed in pairs by bending a suitable length of pipe into
U-shape. The front ends of these pipes are supported upon the bridge wall,
and extend from thence along the tops of the walls separating the gas and air
flues, and have their rear portions supported by the rear wall of the furnace at
and adjacent to the lower edge of the discharge opening. It is preferred to support
the rear ends of the wearing surfaces or tubes 11, at a higher level than the front
ends of the bridge tubes 12, so that when an article or billet is pushed off of the
end of the tubes 11 it will drop onto the bridge tubes with a rotating motion, as
will be readily understood by reference to Fig. 2, and slide quickly over the gas
and air flues 2 and 3. When tubes are employed for the wearing surfaces 11,
and the bridge pieces 12, the outer ends are suitably connected to supply and
discharge pipes so as to insure the circulation of water or other cooling liquid
therefrom, in any suitable manner known in the art. The upper portion of the
opening at the rear end of the furnace is closed by main door 13, adapted to be
raised and lowered in any of the ways known in the art, while the lower portion.
of the opening is closed, by an auxiliary door 14, having attached thereto an
arm 15, which has its upper end pivotally supported or hinged on the main door.
This construction permits of the auxiliary door being forced outward by a billet
sliding down the bridge pieces, thereby permitting of its passage onto the fore
plate 16, by which it is guided onto suitable feed rolls 17.
At the front end of the furnace is secured a shelf or ledge 18, having its upper
surface in line with the upper surface of the wearing faces or tubes 11, and adapted

page_text: to receive the billets or other articles to be heated from the bed of the truck 19
which moves on rails transverse of the furnace and between it and the pushing
mechanism. The pushing mechanism preferably consists of a cylinder 20, having
the outer end of its piston rod 21, suitably shaped or provided with a head 22,
adapted to take an even bearing against the side of an article which it is desired
to force from the bed of the truck into the furnace.
In order to provide for the removal of slag, &c., from the bed of the heating
chamber, a series of openings 23 are formed through the continuous piers and
suitable doors 24 are arranged in the side walls of the furnace in line with sai
opening through the piers. In order to permit of the inspection of the billets
or other articles during their passage through the furnace, and also of the inter
mediate charging of such articles into the furnace, a series of doors are formed. ir
the side walls, as shown in Fig. 2.
It may sometimes occur in the heating of billets, that the portions of the under
surface in contact with the bearing faces or tubes 11, will not be properly heated
on account of their protection by such tubes or surfaces. In order to heat suck
cool portions, the bridge pieces 12 may be arranged out of line with the tubes of
bearing faces 11, as shown in Figs. 3, 5, 9 and 12, so that the surfaces of the billet
which were firmly in contact with the tubes 11, will be exposed to the direct action
of the heat while passing along the bridge pieces.
It is preferred, as herein before stated, to arrange the ends of the tubes 11, and
the surfaces of the bridge pieces 12 on different levels, as shown in Figs. 2 and 4,
so that in case of two billets becoming stuck together while passing through the
furnace, the rotary movement imparted to a billet as it drops off of the tubes 11,
will tear the billets apart. I do not wish to limit myself, however, to the arrange-
ment shown in Figs. 2 and 4, as the bridge pieces may have their front ends on
the same level as the rear ends of the tubes 11, as shown in Figs. 6 and 8. And
further, I do not wish to limit myself to the employment of bridge pieces
independent of the tubes 11, as the latter may be extended as shown in Figs. G
and 7, across the flues 2 and 3, such extensions forming the bridge pieces. As
shown in Figs. 4 and 5, the drop or shoulder for insuring the separation of billeta
as hereinbefore described, may be so located that the billet will drop onto a
horizontal portion of the bridge pieces, from which position it can be drawn by
a hook. But it is preferred to so arrange the shoulder or drop that the billet will
fall onto the inclined portions of the bridge pieces, and slide or roll along the
same onto the feed rollers, as shown in Fig. 2.
In Figs. 12 and 13, I have shown an arrangement of fire chamber 26, for the com-
bustion of solid fuel in such relation to the conduit 4, that the flame and products.
of combustion will pass into such conduit, and thence up the flues or ports 2.
Where the piers are made practically continuous to the bridge 10, as shown
in Figs. 1 to 13, inclusive, the operation of the furnace is rendered diflicult from
the accumulation of slag and cinder on the piers. These accumulations prevent
the easy movement of the billets and also force them up towards the roof. The
slag and cinder running down the sides of the piers cut them away, rendering
renewal of portions of the piers necessary and such repairs are especially difficult
when the inner piers are cut away. In order to avoid these difficulties, the
piers 9 extend from the rear to a point where the heat will be sufficient to melt
the slag and cinder. From this point the tubes 11 are supported by a series of two
or more comparatively narrow transverse piers 26, as shown in Figs. 14 and 15.
In such a construction any slag which lodges on the piers will be pushed off by
succeeding billets, or can be removed by tools inserted through side doors from
which all parts of the piers 26 are readily accessible, not only for the removal of
the slag, but also for inspection and repair.
It is characteristic of my improved furnace, that combustion occurs in the line
of movement of the billets through the furnace, and the flame and products of
combustion are maintained in such line during their flow through the furnace.
It will be observed that the billets or other articles are subjected to the greatest

page_text: heat just prior to their discharge from the furnace, and the heat is of such character
as will not injuriously affect the billets.
Having now particularly described and ascertained the nature of our said in-
vention and in what manner the same is to be performed, we declare that what
we claim is:
5
1. A continuous heating furnace provided with receiving and discharge openings
at or near the ends of the furnace, supports extending from the receiving to the
discharge opening, mechanism for pushing the billets along the supports to or
adjacent to the fuel-ports or point of highest heat, and means independent of the
pushing mechanism for more quickly moving the billets past said fuel-ports or 1
point of highest heat and out of the furnace, substantially as set forth.
2. A continuous heating furnace provided with receiving and discharge openings
at or near the ends of the furnace, supports extending from the receiving to the
dis barge opening, mechanism for pushing the billets along the supports to or
adjacent to the fuel ports or point of highest heat, and means independent of the 1
pushing mechanism for effecting a quicker automatic movement of the billets past
said fuel-ports or point of highest heat and out of the furnace, substantially as set
forth.
3. A continuous heating furnace provided with receiving and discharge openings
at or near the ends of the furnace, supports extending from the receiving to the 2
discharge opening, the supports adjacent to the discharge opening being inclined
to cause the automatic movement of the billets past the fuel ports or point of
highest heat through the discharge opening and mechanism for pushing the billets
along the supports to the point of automatic discharge, substantially as set forth.
4. A continuous heating furnace provided at its opposite end walls with receiving 2
and discharge openings, and having in combination a series of flues or ports through
which the combustibles enter the heating chamber, arranged adjacent to the rear
or discharge opening of the furnace and transversely thereto, supports for the
articles to be heated extending from the receiving opening to points adjacent to
the flues, mechanism for pushing the articles along the supports, and bridge pieces a
adapted to receive the article from said supports and support it while passing over
the flues to the discharge opening, said bridge pieces being sufficiently inclined to
cause the automatic movement of the article over the flues and through the
discharge opening, substantially as set forth.
5. A continuous heating furnace, having in combination a series of flues or a
ports through which the combustibles enter the heating chamber adjacent to the
rear or discharge end of the furnace, supports for the article to be heated, extending
from the front end to points adjacent to the rear end of the furnace, and supple-
mental supports arranged parallel, or approximately parallel, with the main
supports, but in different planes, and extending from the rear ends of the main
supports over the flues, substantially as set forth.
6. A continuous heating furnace having in combination a series of flues or ports
through which the combustibles enter the heating chamber arranged adjacent to
the rear or discharge end of the furnace, supports for the article to be heated,
extending from the front end to points adjacent to the rear end, supplemental
supports extending from the main supports to and over the flues at the rear end of
the furnace, the rear ends of the main support being raised above the adjacent parts
of the supplemental supports, thereby forming a drop for the article being heated,
substantially as set forth.
7. A continuous heating furnace having in combination a series of flues or ports
through which the combustibles enter the heating chamber arranged adjacent to
the rear or discharge end of the furnace and transversely thereof, supports extending
from the front end of the furnace to points adjacent to said flues, supplemental
supports or bridge pieces extending from the main supports over the flues, said
supplemental supports being inclined, substantially as set forth.
3. A continuous heating furnace having in combination continuous piers or

page_text: supporting walls extending longitudinally from the front towards the rear end of
the furnace, one or more piers arranged transversely of the furnace between the
bridge wall and the ends of the longitudinal piers, and bearing pieces or supports
for the billets, etc., arranged on the longitudinal and transverse piers, substantially
as set forth.
9. The combination of a continuous heating furnace having openings at its
opposite ends, supports for the billets, etc., extending through the furnace from the
discharge to the receiving opening, the supports adjacent to the discharge opening
being sufficiently inclined to cause the automatic movement of the article past the
fuel ports through said opening, a fore plate arranged at the front end of the
furnace on or approximately on a level with the billet supports, a truck movable
into line with the fore plate and having its bed or platform on or approximately
on a level with the fore plate, and mechanism for pushing the billets, etc., from the
truck into and through the furnace, substantially as set forth.
ALEXANDER LAUGHLIN.
JOSEF REULEAUX.
DARWIN S. WOLCOTT.
Witnesses:
F. E. GAITHER.
Dated at Pittsburg, Pa., U.S.A., this Twenty-fourth day of April, A.D. 1897.