improvements in Steam Bollers and Furnaces therefor
Year: 1897

page_text: Date of Application, 22nd Mar., 1897
[Communicated from abroad by THOMAS WARD MCMAMES, Capitalist, of 2741,
Lucas Avenue, SIMEON TAYLOR PRICE, Attorney-at-Law, of 4238, Westminster
Place, and JoHN COCHRAN BURNESON, Steam Engineer, of 3705, Garfield Avenue,
all in the City of St. Louis, and State of Missouri, United States of America.].
improvements in Steam Bollers and Furnaces therefor,
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of the Agency for Foreign
Patent Solicitors, 322, High Holborn, in the County of Middlesex, 6, Lord Street,
Liverpool, and 6, Bank Street, Manchester, both in the County of Lancaster, and
Lower Temple Street, Birmingham, in the County of Warwick, Civil Engineer, do
hereby declare the nature of this invention to be as follows:-
-
This invention relates to boilers and their furnaces and the art of cleaning boilers
and connecting parts and preventing the formation of scale therein.
The improvement in the art of cleaning boilers, and connecting parts through
which water passes to, or from, the boilers, and preventing the formation of scale,
consists in creating by mechanical means during the active generation and supply
of steam a constant current of water along highly heated portions of water heating.
surface desired to be kept clean, and over and away from such highly heated surface,
and in that way preventing sediment from settling upon such surfaces and forming
scale. It consists also in causing the current or currents created and used for the
purpose specified to carry sediment from said highly heated portions of the boiler
to one or more points where it can be blown from the boiler through a suitable
outlet or outlets and in blowing it from the boiler from time to time as it accumu-
lates. It consists further, in causing sediment to be carried away from highly heated
surfaces by mechanically created currents and deposited in the mouth of a mud leg
and in arresting a current moving towards the mouth of such a leg by means of an
opposite current caused to meet it above the mouth of the leg.
The improvement in the boiler consists in arranging a right and left hand con-
veyor in position to create opposite currents from highly heated surfaces towards
an outlet of sediment. I may also use other equivalent mechanism for producing
the same result. It consists further in means for suspending a screw conveyor from
the flues of a flue boiler. For this purpose I use two frames each consisting of two
plates and screw bolts and nuts for clamping said plates together, and upon the
supporting flues. The lower plate or bar in each case has a slot therein parallel
with the conveyor and in each frame the ends of the plate where they rest against the
flues are corrugated. The rear frame may have a forwardly extending arm con-
taining the slot above mentioned. The lower plate of the forward frame is
preferably in the form of a cross with short arms extending to the front and rear
and with a slot through the rear arm parallel with the conveyor and a vertical
bearing for a vertical shaft in the forwardly extending arm. I prefer to support
the conveyor in two bearings each having a screw threaded rod attached thereto
and extending up therefrom. The rod attached to the rear bearing extends up

page_text: through the slot in the lower plate in the rear frame and the rod attached to the
opposite bearing extends up through the slot in the lower plate of the front frame;
and both of said rods are secured in position by means of a nut above and a nut
below the slot in the frame supporting it. A jam nut is preferably used to prevent
the upper nut from becoming loosened.
I preferably drive the conveyor by means of a vertical shaft extending down
through the boiler and passing through the bearing formed in said forward frame.
Collars on said shaft, one above, and one below the lower plate of said frame, prevent
vertical movement. This vertical shaft extends through the top of the boiler and
its upper end is supported in a gland preferably held in place in the boiler shell by
an inside and an outside nut. It is preferably provided with a long sleeve which
extends down into the boiler and affords the shaft a strong support. Rotary motion
may be communicated to this shaft by any convenient means. Its lower end and
the adjoining end of the conveyor shaft are both preferably squared or otherwise
shaped so as to prevent gears placed thereon from turning and each carries a bevel
gear. These gears interlock and keep each other in place.
The improvement in furnaces consists first, in using a down draft water tube
grate whose bars are all arranged substantially in the same plane and are widely
spaced apart and beneath said down draft grate, an updraft grate with bars arranged
more closely together than those of the upper grate. Between the grates is arranged
a combustion chamber with which an escape flue connects. The fuel used is fed
into the upper grate and part of it is there consumed and part falls between the
widely spaced bars of said grate down onto the more narrowly spaced bars of the
lower grate and is burnt upon them. An intense heat is created between these two
grates which consumes the smoke.
The improvement in furnaces consists further in the construction of the grate
whose bars are water tubes and discharge into a transverse water chamber which in
turn discharges into the boiler through suitable passages. This water chamber
preferably projects beyond the grate at one or both sides, and the projecting ends
are preferably wholly or partly shielded from the heat of the furnace. One or both
projecting ends are provided with outlets for sediment, and means for opening and
closing the same.
In connection with the grate I preferably use a pump for assisting the circulation
of water through it. I preferably use a pump in the form of a screw conveyor
which may be either single or double bladed, but I prefer a right and left hand screw
.- conveyor. This conveyor is preferably placed in the transverse water chamber into
which the tubular grate bars discharge and support it in bearings. I prefer to place
it near the bottom of the water chamber. I also provide suitable means for causing
the conveyor to rotate and perform two functions viz.;
1st, That of drawing water through the tubular grate bars and forcing it into the
boiler, and
2nd, Creating a current or currents along the bottom of said water chamber towards
one or both ends and towards a sediment outlet or sediment outlets and in that way
forcing sediment towards such outlet or outlets and causing it to accumulate where
it can be readily blown off.
I preferably connect said water chamber with the boiler by means of pipes leading
from its top and preferably place the outlet or outlets for sediment in its bottom:
near the end or ends to which currents are caused to flow by said conveyor.
Dated this 00nd das. & Manah 1907
W. P. THOMPSON & Co.,
322, High Holborn, London, W.C., Patent Agents for the Applicant.

page_text: I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of the Agency for Foreign
Patent Solicitors, 322, High Holborn, in the County of Middlesex, 6, Lord Street,
Liverpool, and 6, Bank Street, Manchester, both in the County of Lancaster, and
Lower Temple Street, Birmingham, in the County of Warwick, Civil Engineer, 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:-
As is well known, the formation of a stony crust or scale in steam boilers is a
very common thing and a great evil. It always results in a waste of fuel, frequently
causes serious injuries to the encrusted parts by burning, and sometimes results in
disastrous boiler explosions. In all such cases the scale or crust is produced by a
deposit of sediment upon a highly heated surface and the baking of such sediment
upon such surface. It adheres to the surface upon which it is formed, and grows
thicker and spreads as more sediment is from time to time, deposited, and the
thicker it becomes the greater the loss of fuel, and the greater the likelihood of
injuries to the boiler.
When water is used which contains impurities adapted to form scale, the forma--
tion of scale upon the more highly heated surfaces of the boiler, is assisted by the
currents set up in the boiler by the introduction of feed water and the application.
of heat. These currents tend to move along the bottom of the boiler towards the
hottest points and carry all the sediment precipitated to those points and deposit
it there, where it is most likely to form scale and do the most harm.
Another source of loss in the production of steam in boilers is the imperfection of
the boiler furnaces used. Ordinarily about twenty-five per cent. of the fuel con-
sumed is wasted, by reason of its incomplete combustion. Among the most
economical of the furnaces heretofore used have been those having down draft
water tube grates but the circulation of water through grates of this
class has not been satisfactory when the steam pressure in the boiler has been high
and the tubular grate bars and connections have frequently burnt out, and this has
prevented such grates from coming into common use.
These improvements relate in part to the art of cleaning boilers and parts of boiler
systems and preventing the formation of scale therein; in part to the mechanism
used in said art; and in part to a novel form of furnace and a form of furnace grate
which are preferably used. The chief objects of said improvements are first to pre-..
vent the formation of scale in steam boilers and connecting parts and the losses
and injuries commonly resulting from the presence of scale in such boilers and
connections; second, to provide an improved boiler furnace having a down draft
water tube grate; third, to provide means for increasing the circulation of water
through the grate, and preventing the formation of scale in the grate and parts
immediately connected therewith.
Our method of preventing the formation of scale upon the highly heated surfaces
of boilers and connecting parts consists in mechanically creating a current over
and away from such surfaces and towards points where sediment can either escape
at once from the boiler proper, or be blown out of the boiler system entirely from
time to time as it accumulates, and in preventing sediment from being deposited
and remaining upon such highly heated surfaces by means of such currents; and,
causing said currents to deposit it elsewhere. By frequently removing accumulated
sediment the water in the boiler is purified and is caused to dissolve sediment, if
any, deposited upon flues out of reach of said mechanically produced currents.
Where the sediment is not at once removed from the boiler proper but is caused

page_text: to accumulate for future removal; it is caused to accumulate at a point or points
where the heat is not sufficient to cause the formation of scale. Another and minor
feature which in some cases is useful and in others is dispensed with is the arresting
of sediment bearing currents at points where they are desired to make deposits by
means of opposing currents which are caused to meet them at such points.
Said improvements in the art of cleaning steam boilers and parts of boiler systems
and preventing the formation of scale therein may be used in all kinds of steam
boilers but have been illustrated together with said improvements in boilers,
furnaces and grates in connection with a return flue horizontal cylindrical boiler
of a common type.
In the accompanying drawings,---
Fig. 1 is a vertical longitudinal section of the entire apparatus on line 1-1
Fig. 2;
Fig. 2 is a transverse section on line 2-2 Fig. 1;
Fig. 3 is a detailed transverse section on a reduced scale on line 3-3 Fig. 1 with
the conveyor and its rear support removed;
Fig. 4 is a similar view on line 4-4 Fig. 1;
Fig. 5 is a view in cross section of a modification of the parts shown in Fig. 4;
Fig. 6 is a detailed vertical central longitudinal section on an enlarged scale of a
transverse water chamber at the rear of the upper grate of the furnace, into which the
tubular bars of said grate discharge, showing a right and left hand screw conveyor
in side elevation arranged therein;
Fig. 7 is a similar view of a modification in which but one outlet for sediment
is shown and in which the conveyor illustrated has but a single blade;
Fig. 8 is a detailed view in front elevation on an enlarged scale of a frame for
suspending the front end of a conveyor from the lower flues of the boiler and for
holding the lower end of a driving shaft in position;
Fig. 9 is a similar view of a rear supporting frame and a bearing suspended there-
from;
Fig. 10 is a plan view on the same scale of the bottom plate of said front frame;
Fig. 11 is a similar view of the bottom plate of said rear frame; and
Fig. 12 is a detailed sectional elevation on an enlarged scale of a portion of the
gland through which said driving shaft passes up, out of the boiler.
Similar letters refer to similar parts throughout the several views.
A represents the boiler and a the flues thereof. It is provided with a mud leg a
whose mouth a² receives deposits from the boiler and whose lower end discharges
into the usual mud drum a³.
B represents the brick work surrounding the boiler and furnace.
C represents a conveyor which preferably has a right hand blade c, and a left
hand blade cl, attached to a common shaft 2, and terminating opposite each other
with a space between them. This conveyor is preferably arranged longitudinally
and centrally near the bottom of the boiler, and so as to bring the space above
the mouth a² of the leg a¹. The front end ct of the shaft c² is preferably squared,
or otherwise shaped so as to prevent a pinion slipped thereon from turning upon it
and carries a pinion 5.
The conveyor is journaled in bearings c and c, respectively attached to the lower
ends of vertical screw threaded rods 88, which are preferably suspended from the
lower row of flues a and held in place by means of frames D and E.
4
The frame D supports the rear end of the conveyor. It preferably consists of a
cross plate resting upon the tops of the lowermost row of flues, and a cross bar 6 5
held against the undersides of the same row of flues and having a forwardly pro-
jecting arm & containing a vertical longitudinal slot d³; and means for fastening
said plates together and clamping them upon said flues. The bar is preferably
corrugated transversely on its upper side in the neighbourhood of its ends, and
contains bolt holes and said plate d and cross bar are preferably secured 5
together and clamped upon the intervening flues by means of screw bolts d6 which
pass through them and whose heads preferably rest against the lower side of the

page_text: bar d and which are preferably each provided at their respective screw threaded
ends, with an ordinary nut d8 and a jam nut d.
The screw threaded rod attached to the rear bearing e passes up through the
slot d³ in the arm of the frame D and is fastened securely in position, by means
of a nut e beneath said arm d²; a similar nut ce above said arm, and a jam nut c¹¹.
Rear movement on the part of the conveyor shaft is prevented by the thrust in the
opposite direction given the conveyor when it is rotated. Endwise move-
ment of the conveyor shaft towards the front end of the boiler is
prevented by means of a collar el resting against the inner end of the bearing c
and secured to said shaft.
The frame E consists of a transverse plate e pierced by bolt holes; a cross E¹
having two long arms el transversely corrugated on top near their respective outer
ends a rearwardly projecting arm e, pierced by a vertical longitudinal slot e³, and
a forwardly projecting arm containing a bearing e5 for a vertical shaft; and screw
bolts ee having common nuts e7 and jam nuts for securing said cross and plate
together.
The plate e is shown resting upon the lowermost row of flues a and the long arms
of the cross E are preferably held up against the under sides of the same flues.
The bolts e are provided with heads e, and pass upward through the cross E¹ and
the plate e and are caused, by screwing their nuts e home, to clamp the plate e
and the cross E' firmly upon the flues between them. The loosening of the nuts e
is prevented by the jam nuts e, and the corrugated surfaces of the cross E¹ tends to
prevent its slipping endwise.
F is a vertical driving shaft. It passes through the shaft hole in the arm e¹
of the frame E, and its lower end is preferably squared or otherwise formed so as to
afford a seat for a gear wheel upon which the latter cannot turn. It is provided
with two collars f and fl each provided with a set screw f2 by means of which
they are secured in position. The collar ƒ preferably rests upon the top of the
arm e and thus limits the downward movement of the shaft while the collar f¹ is
arranged directly beneath said arm and prevents the shaft from lifting. Upon the
lower end of the shaft F a bevel wheel f³ is slipped which meshes in with the
pinion and when said bevel wheel and pinion are made to mesh they lock each
other in place so that no other means of preventing outward movement on the part
of either, are required.
The shaft F passes up and out through a gland G secured in an opening in the
top of the boiler, and having a sleeve g which preferably extends down into the
boiler and affords the shaft a firm support. This sleeve preferably has a concave
head g containing a packing upon which rests a follower g³ which is forced
down upon it by means of a nut 9. Said sleeve is screw threaded for a portion of
its length and is preferably secured in position by means of a nut g on the inside
of the boiler shell, and a similar nut 96 upon the outside. A washer g made concave
on the bottom so as to fit the boiler shell, and flat on top, is preferably interposed
between the boiler shell and the nut 6 in order to reinforce and strengthen the
former. To the top of the shaft F a bevel gear H is preferably secured to which
motion is preferably communicated from a shaft h through a pinion h. This shaft
is preferably supported in whole, or in part, by bearings preferably attached to
and supported by the shell of the boiler. Upon the shaft h a pulley h³ is shown.
I represents a right and left hand screw conveyor located in the mud drum a³.
Its shaft i is journaled in glands arranged in the ends of the drum and it is pro-
vided with two blades which terminate opposite each other above the mouth of
the blow off pipe. To the end of the shaft i a pulley is shown attached.
L represents a grate composed of widely spaced bars in the form of water tubes /
which at their front ends, preferably connect with a transverse water chamber M
which is in practice, usually constructed in the form of a drum as shown. Where
the form of boiler illustrated is used two pipes M1 preferably extend down from
near the bottom of the boiler in the neighborhood of the front end thereof, and
connect with the water chamber M near opposite ends of said chamber substantially
as shown in Fig. 4. Other methods of connecting the chamber M with the boiler

page_text: 'may be used however. One of these is shown in Fig. 5 in which the connection
consists of a single vertical pipe M¹.
The rear ends of the tubular bars 1, of the grate L connect with a transverse
water chamber N whose form is not an essential feature of our improvement but
which we preferably construct in the form of a drum as shown in Figs. 3, 6, 7.
The water chamber N is preferably larger in cross section than the chamber M and
longer than the width of the grate, and preferably projects beyond it on each side
substantially as shown in Fig. 3, and these projecting ends are preferably either
partially or wholly shielded from the heat of the furnace by brick work. It is
preferably connected with the boiler by means of a pair of pipes N¹ which extend
upwards from near opposite ends of said chamber and preferably connect with
opposite sides of the boiler above the level of the points at which the pipes M¹ con-
nect with it. This particular form of connection is not essential however, and may
be varied in many ways as will be obvious, without departing from the essence
of our improvements.
The chamber N is preferably provided with an outlet for scale and sediment,
near each end thereof, and preferably through its bottom. These outlets are pre-
ferably in the shape of common blow off pipes n¹ each provided with an ordinary
blow off cock n² for opening and closing the outlet substantially as shown in Fig. 3,
and each end of the chamber is preferably, but not necessarily, provided with a man
hole n³ to afford convenient access to its interior.
The space, if any, between the chamber N and the boiler A is preferably closed
by brick work n' or other suitable means, so as to force the products of the combus-
tion of fuel upon the grate L, to find an exit downward, between the tubular bars/
which together with the front of the water chamber N are in consequence subjected
to a very intense heat.
0 (Fig. 1) is a door through which fuel can be thrown upon the grate L.
At some distance below the grate L an ordinary updraft grate P with bars
more narrowly spaced than those of the former grate, is preferably located. Beneath
the grate P there is an ash pit p¹ and between said grate and the grate L there is a
combustion chamber Q from which a flue g is shown leading back to the rear end
of the boiler. The grate P is supplied with fuel by the upper grate L between
whose widely spaced bars a considerable quantity of partially consumed fuel falls.
and is consumed upon said lower grate. The heat between the two grates and said
chamber N and on the rear side of said chamber, is so intense that it consumes the
smoke and the bars and water chamber N can only be preserved from destruction
by keeping up a constant current of water through them and preventing the forma-
tion of scale therein.
The formation of scale either in the chamber N or one of the bars is almost
always followed by its being either injured or destroyed by the heat.
Water circulates through the grate L from front to rear and the bars 7 discharge
into the chamber N. While- steam is being raised the circulation through said
grate and the water chambers with which it connects is very rapid and there is little
danger at such times of either the bars or drums burning but when the steam
pressure in the boiler becomes great the circulation of water in the grate and water
chambers is interfered with and becomes sluggish and sometimes temporarily stops.
At such times scale is liable to form in said tubular grate bars, and the water
chamber N, and cause serious trouble. In order to prevent the stoppage of the
circulation of water through said water tube grate at any time and to make its
circulation more rapid when there is a high steam pressure in the boiler we intro-
duce a pump into said boiler system for forcing water to flow rapidly through said
water chambers and tubular grate bars. The pump which we prefer to use is in
the form of a screw conveyor R (Figs. 1, 6, 7) and in order to enable it to not only
increase said circulation but also assist in preventing sediment from accumulating
near the center of the chamber N by constantly forcing it towards one or both ends
of said chamber, and causing it to accumulate where it can be readily blown off
through the blow off pipe or pipes connected with the chamber N, we preferably

page_text: arrange. said conveyor in said chamber near the bottom thereof, and journal its
shaft in bearings which are preferably in the form of glands located in the ends
of said chamber as shown in Figs. 3, 6 and 7. End motion is preferably prevented
by collars and to one end of said shaft r we preferably attach a pulley or other
means for communicating motion to the conveyor which is preferably kept in con-
stant motion after steam is raised, and while it is being actively generated and
supplied. The screw conveyor R is preferably provided with a right hand blade
and a left hand blade 5 which each extend from about midway between the ends
of the chamber 1 towards opposite ends, so that when the conveyor is caused to
rotate in the proper direction, the conveyor blades tend to force water and sediment
from the central portion of the chamber towards opposite ends thereof and thence
up through the pipes N¹ into the boiler A; at the same time drawing
water from the tubular grate bars into said water chamber and thus
strongly assisting the grate circulation. The sediment forced away from
the central portion of the chamber N is caused to accumulate around the inner
ends of the blow off pipes n¹ (Fig. 3) and may be discharged from the chamber N by
merely opening the blow off cocks which should preferably be done where the
water is very bad, every four hours, and in all cases where any sediment is deposited,
at least once a day.
In Fig. 7 we have shown a conveyor R having a single blade extending sub-
stantially from one end of the chamber N to the other, and adapted to create a
current along the bottom of the chamber N from end to end, towards the single
blow off pipe n¹ shown. This form of the device is designed for use where, because
of the arrangement of the boiler in a battery, or for some other reasons, only one
blow off pipe can be conveniently applied to the water chamber N. In such cases
I prefer to make the pipe N¹ nearest the blow off pipe, larger than the one leading
from the opposite end of said chamber, substantially as shown in Fig. 7.
The operation of the furnace and grate and the apparatus connected therewith
have been sufficiently described. They save about twenty-five per cent. in fuel and
consume nearly all of the smoke produced and said apparatus greatly prolongs the
life of the water tube grate.
The apparatus within the boiler operates as follows:
As soon as steam is raised, the conveyor C is set in motion in the boiler by means
of the mechanism described and is preferably kept in operation constantly as long
as the active generation and supply of steam by the boiler continues. The primary
effect of the rotation of the conveyor is to create two currents of water. The
blade c creates a rearward current and the blade cl a forward current both of which
flow along the bottom of the boiler and meet above the mouth a² of the mud leg a¹
where they tend to arrest each other. The current flowing from above the chamber
directly behind the furnace carries with it all sediment which would otherwise
settle upon the highly heated surface at that point and form scale, and when it is
arrested above the mouth of the mud leg it deposits the sediment carried, or most
of it, while the current flowing forward keeps any sediment from accumulating and
forming scale upon the highly heated surface between the mud leg and the rear end
of the boiler, and joins the rearward current in depositing sediment in the mouth
of said leg. By keeping the conveyor in constant operation and forcibly and con-
tinuously overcoming the tendency of the water in the boiler to flow from all other
points to the most highly heated surface and there deposit sediment, and by carrying
all the sediment to the mouth of the mud leg and there depositing it, I cause
sediment to descend into the mud drum a³. By causing the screw conveyor in the
mud drum to rotate, the sediment deposited in the drum can be forced to gather
above the mouth of the blow off pipe a and, blown off at will. The conveyor in the
drum may be kept in constant motion but that is not essential and the drum and
the conveyor therein may be dispensed with entirely if desired, as will be obvious
inasmuch as the frequent removals of sediment by blowing it off is desirable in any
case, for it causes the water to become purified and dissolve sediment deposited on
Blues at other points not effected directly by the mechanically produced currents

page_text: and the boiler to be kept perfectly clean. It is not essential that the conveyor in
the mud drum should be kept in motion constantly. It is sufficient, to set it in
motion a short time before the blow off valves are opened and keep it going until
they are closed. I prefer to use a mud drum in connection with my apparatus but
as will be obvious such a drum may be dispensed with if desired, where the sedi-
ment is blown off frequently.
The special form of gland described is very desirable by reason of the extended
support it furnishes the upper end of the driving shaft F.
The cross E¹ of the frame E holds the adjoining ends of the shaft c² and F in
their proper positions with reference to each other regardless of the expansion and
contraction of parts, and keeps the bevel wheel f³ and the pinion from getting
out of mesh; and the slot d³ in the arm 2 of the frame D and the slot e' in the arm e
of the frame E enable the conveyor to be nicely adjusted to and from the shaft F
without moving said frames which last are both readily adjusted and when
necessary removed.
When said bevel wheel and pinion become worn the bevel wheel H is preferably
removed from the shaft I.and the collar f¹ upon said shaft loosened, and the shaft F
is then pushed up so as to allow the wheel f³ to drop therefrom and be slipped out
laterally.
The pinion can then be removed from the shaft c² without difficulty, and new
gears inserted. If after the removal of the worn gear wheel f³ and pinion c³, it is
desired to remove the conveyor from its bearings, that can be easily accomplished
by merely loosening the nuts and e upon the bolts e and sliding the frame E
forward upon the supporting flues far enough to cause the front end of the shaft c
to drop from the bearing c. By drawing the conveyor forward it can then be caused
to drop from the bearing . All this can be done without entering the boiler where
the boiler is provided with the usual man hole K such as is shown in dotted lines
in Fig. 2 and if desired the conveyor can be both introduced and removed through
such a man hole.
We have described the form of apparatus we prefer to use in practicing our method
of cleaning boilers and preventing scale, but as will be obvious, other forms of
apparatus may be used instead of the one shown.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is:-
In a steam boiler:
1. The hereinbefore described method of cleaning the heated surfaces and pre-
venting formation of scale thereon which consists in mechanically causing a current
of water to flow intermittently or continuously during the active generation and
supply of steam, and the deposit of sediment adapted to form scale, over and away
from a highly heated portion of the water heating surface, and along the bottom
of that portion of the boiler to which such surface belongs and carry away from such
highly heated surface sediment which would otherwise be deposited and remain
thereon, and cause the same to be deposited elsewhere, substantially as described.
2. The improvement in cleaning steam boilers having mud legs extending down
therefrom, consisting in mechanically causing a continuous current of water to flow
from the hottest portion of the boiler to the mouth of said leg and there arresting
its course by an opposing current moving from an opposite direction and in that
way causing it to deposit sediment carried thereby in said leg substantially as
described.
3. The combination of a grate having tubular bars; a transverse water chamber
with which said bars connect at one end, a revoluble right and left screw conveyor
in said chamber and means for rotating said conveyor and creating two currents in
said water chamber from the central portion thereof towards opposite ends.
4. The combination of a down draft water tube grate; an up draft grate beneath

page_text: it and mechanism for forcing a current of water to flow through said down draft
grate.
5. The herein before described mechanism for mechanically creating currents
and determining the deposit of sediment constructed and operating substantially
as described with reference to the accompanying drawings.
6. The hereinbefore described arrangement of boiler furnace constructed and
operating substantially as described with reference to the accompanying drawings.
W. P. THOMPSON & Co.,
Of London, Liverpool, Manchester and Birmingham,
Patent Agents for the Applicant.
W. P. THOMPSON & Co.,
Of London, Liverpool, Manchester and Birmingham,
Patent Agents for the Applicant.