IMPROVEMENTS IN STEAM GENERATORS OR BOILERS, WATER HEATERS, AND APPARATUS THEREWITH
Year: 1866

page_text: LETTERS PATENT to Joseph Twibill, of Irvine, in the County of Ayr,
North Britain, Engineer, for the Invention of "IMPROVEMENTS IN STEAM
GENERATORS OR BOILERS, WATER HEATERS, AND APPARATUS
THEREWITH."
CONNECTED
Sealed the 8th March 1867, and dated the 15th September 1866.
PROVISIONAL SPECIFICATION left by the said Joseph Twibill at tho
Office of the Commissioners of Patents, with his Petition, on the
15th September 1866.
I, JOSEPH TWIBILL, of Irvine, in the County of Ayr, North Britain,
Engineer, do hereby declare tho nature of the said Invention of "IMPROVE-
MENTS IN STEAM GENERATORS OR BOILERS, WATER HEATERS, AND APPARATUS
CONNECTED THEREWITH," to be as follows, that is to say:-
This said Invention, which may be comprised and provisionally specified
under two heads, has reference to new or improved additions to steam
generators or boilers and water heaters of the ordinary forms and con-
structions now in general use, and particularly those with large open flues,
and also to a considerable extent to that of improvements upon or in
connection with those forms and constructions of steam boilers and water
heaters forming the essential part of the Invention for which Royal Letters
Patent were granted to the Petitioner on or about the 27th day of January
1865, and No. 243, and which improvements render such steam generators
or boilers and water heaters much more economical and efficient than
as heretofore constructed.

page_text: Under the first head or part this said Invention consists essentially in the
adaptation and use of small supplementary heating vessels of a portable
construction formed mainly of sets or "stacks" of parallelly arranged tubes
in some cases and circumstances enclosed in outer cylinders, boxes, "shells,"
or "jackets," applied or placed within the main flues formed in or passing
through large steam boilers and water heaters formed in this way, many of
which are now in common use, or otherwise erected or placed within the main
flues of such boilers, formed in the brickwork between the boilers and their
chimneys, or within chambers formed for the purpose in connection with
these flues. These supplementary heating vessels being connected at their
top and bottom ends to the upper and lower sides of the fluos or ends of their
main boilers by short coupling or branch pipes for the duc circulation of the
heated currents of water or water and steam, according as they are used for
steam generators or for water heaters only, these branch pipes being casily
detached for the repairs or removal of the vessels at pleasure, it will be
obvious that the construction, size, disposition, and arrangement of these
supplementary heating vessels and their tubes will depend materially upon
the size of the boilers and the arrangement of their flues to which the vessels
are to be fitted, furnished, or adapted. When. a set of tubes which form the
main heating surface of the supplementary heating vessel is to be placed
within a main flue passing through a horizontal or vertical boiler it is pre-
ferred to place the tubes parallel with the flue, and to havo them all enclosed
within a casing or "shell" a few inches smaller all round than the flue, but of
the same shape, so as to fill up nearly the whole area and space of the flue for
a considerable length at the back end of the boiler, or the upper end when it
is a vertical boiler, say, varying from about a sixth to three-fourths of the
whole length of the boiler as considered judicious. In some cases and
circumstances this form and arrangement of the tubes and vessel may also be
fitted so as to lay parallel in and nearly fill up one of the main flues formed
in the brickwork loading from the main boiler to which the vessel is to be
connected and its chimney. In both of these latter modifications, in which
the tubes are encased in an outer shell or vessel and laid parallel to the
flue, the flame and heated products of combustion from the furnace will
pass through the interior of the set of tubes and all round their casing or
shell, so as to heat the water or water and steam surrounding and circu-
lating round the outer surface of the tubes within the vessel, which
arrangement adds materially to the heating surface of the boiler, and cause
the flame and heated gases from the furnace to act more directly or
effectually upon the surface of the main fluc, so as to absorb or utilize

page_text: the heat from the flame and gases in a more perfect manner before reaching
the chimney than has heretofore been done in such boilers with large
open flues.
In most cases, when these vessels or sets of pipes or tubes
are intended to be built into the brick flues of main boilers or chambers in
connection with such flues, whether these boilers are of ordinary forms or con-
structions or of the tubular class constructed in accordance with the Invention
herein-before referred to, and for which the Petitioner received Royal Letters
Patent, it is preferred to arrange the pipes or tubes in rectangular and vertical
or transverse "stacks" of parallel rows, connected at the bottom and top ends
by sockets or by flanges to horizontal shallow chests, transverse or longitudinal
connecting pipes; or when the tubes or pipes are arranged transversly they
are connected at both ends to vertical and longitudinal narrow chests or con-
necting pipes, so as to form a complete vessel having the water or water and
steam circulating within the pipes or tubes, and having the flame and heated
products of combustion from the furnace passed through the flues or chambers
containing the tubes so as to act or impinge on their outer surface, much in
accordance with the arrangements of the steam generators and water heaters.
forming the main feature of the Petitioner's former patented Invention herein-
before referred to.
In the modifications of supplementary heaters, in which the flame and
heated products of combustion are made to act upon the outer surface of the
"stacks" of tubes or pipes, scrapers are employed mounted upon the pipes
in sets so as to move to and fro upon the pipes, and thus keep their surface
always clean for the more perfect conduction of the heat.
The improvements under the second and last head of this Invention have
reference to new or improved forms or constructions of the said scrapers,
and to mechanical arrangements of mechanism or apparatus for imparting a
reversing and reciprocatory action or motion to a number of these scrapers
mounted upon the sets or "stacks" of parallelly arranged tubes of these
heating vessels, but which are also equally applicable for scraping and
actuating the scrapers upon the pipes of the steam boilers and water heaters
constructed in accordance with the Petitioner's patented Invention herein-
before referred to, and also for so actuating the scrapers of other such boilers
or water heaters in which the pipes are arranged nearly parallel to each other.
And these improvements under the second and last head of this Invention,
when applied to a set or "stack" of vertically arranged tubes of such vessels
and boilers as herein-before referred to, consist of round rings encirculing the
pipes, arranged by preference in squares or rectangular sets of twelve, sixteen,
twenty, or thirty, formed in rows of three by four, four by four, four by five,

page_text: and five by six respectively, which rings and arrangement of them upon the
pipes in sets is not new, having before been used, but are now actuated in a
new or improved manner by having a strong longitudinal or transverse hori-
zontal bar or plate passing through the central division of these rectangular
rows of pipes, with short double lateral arms projecting out between every two
pipes on each side of it below the scraping rings so as to carry them, and
having longer arms at intervals between the rows or at the outsides of the
rows of tubes, to which other parallel bars are attached for every extra single
or double row of pipes and rings there are on each side of the first central
bar, so as to carry these other rows of rings by double fingers in a similar
manner; these finger bars thus forming a strong frame, which when raised by
a stem or rod and chain attached to the centre of the frame for the purpose
raises all the ring scrapers. In lieu of the rings, plates may be used formed
with a round hole through them, or with semicircles at each side of them, so
that either one or two of these plates would encircle a pipe when scraping it;
upon the top of these rings or plate scrapers a thin transverse or longitudinal
flat guard plate is screwed down to the frame, moving and carrying them (with
stop pieces between them rather deeper than the thickness of the scrapers)
between every alternate row of pipes, which allows each of the scrapers to
move freely transversely to suit the irregularities of the pipes as they
are moved up and down or moved to and fro upon the pipes by the cross
frame and guard plates attached to the stem and chain, but not so loosely as
to allow the scrapers to fall to such an angle as to become tight or get
jammed upon the pipes. In some cases, when desired, these flat plate scrapers
might be made to extend right across the whole row of pipes, and have semi-
circles formed in them on each side to embrace half the circumference of two
rows of pipes, and these cither placed longitudinally or transversely in each
space between the rows of tubes, and horizontal or vertical between the
moving frame and guards (according as the pipes are placed vertical or
horizontal respectively,) for retaining and actuating them properly while
scraping; or otherwise one or more of these long plates for embracing and
scraping two rows of tubes at a time may be directly attached to a guiding
or actuating rod, either worked by handles and manual power, or otherwise
by motive power.
The improvements under the second and last head of this Invention, for
giving the necessary reciprocatory and reversing motion to the whole sets of
scrapers into which the whole "stack" or set of pipes or tubes composing
the vessels, boilers, or water heaters are divided, more particularly applicablo
to those in which the tubes are arranged vertically, consist in the application

page_text: and use of a single long shaft working in bearings formed in standards
or brackets bolted to the upper longitudinal or cross pipes, and placed in a
longitudinal line over the centre of the whole set of vertical pipes. The sets
of scrapers are arranged in two parallel rows, one on each side of the shaft, so
as to be worked in pairs transversely up and down by a single chain and
chain wheel for each pair. The shaft having, therefore, as many chain wheels
keyed on it as there are double sets of scrapers to be worked in the whole
length of the set or "stack" of pipes, the wheels being so placed and of such
a diameter that when the chains are passed over them the two ends of each
chain are in the exact vertical centre line of their respective sets of scrapers,
plates, and bars, and are there coupled to the eye of the rod attached to the
centre cross bar or plate of the scrapers. In place of the chain wheels and
chains large rack wheels may be keyed on the shaft, gearing into racks
attached to rods fixed to the centre cross bar of the scrapers in lieu of the
chains. By these arrangements when the long shaft is turned in one direction
it will by means of the chain wheels and chains or the rack wheels and rack
rods raise the whole longitudinal row or sets of scrapers on the one side of the
shaft and depress the whole of those on the other, and vice versa; when the
shaft is reversed or turned in the opposite direction it will raise the whole
longitudinal row of scrapers which were depressed on the one side, and lower the
row which was raised on the other side respectively. When it is desired to
work the scrapers upon the pipes arranged in a horizontal or in an angular
plane or position, and the chains and chain wheels are used for pulling the
scrapers forward in one direction by direct force in either of these planes
respectively to suit the dispositions of the pipes, a similar shaft with chain
pulleys for reversing and transmitting the power is mounted along the centre
line and parallel to the first driving shaft at the opposite side of the set of pipes
or tubes, and back drawing chains passed round the transmitting chain pulleys,
and attached to the back or other sides of the cross bars of all the sets of scrapers,
so that when the actuated and driving shaft is turned in one direction it will
draw forward all the scrapers on one side of the shaft to the extreme end of
their pipes nearest itself in one direction and through the other back chains,
and the transmitting shaft and chain pulleys will at the same time pull all the
other half of the scrapers to the other end of their pipes near the rolling or
transmitting shaft and chain pulleys in the opposite direction, and vice versa
when the driving shaft is turned in the opposite direction it will pull forward
the other half of the scrapers, and through the transmitting chains and chain
pulleys at the back draw back the half of the scrapers which had been
previously pulled forward by the direct, force of the driving shaft that is

page_text: the driving and reversing or turning of the long actuating shaft alternately draws
all the scrapers from the one end of the pipes to the other. In some cases to
save this long traverse of the scrapers two sets of scrapers are mounted on
the same set of pipes and attached to the same actuating stem or rod, the rod
in some cases being worked in guides, and this arrangement is particularly
adapted for the pipes when laying in a horizontal position. The driving and
reversing of the long shaft is effected under one arrangement by a mangle
wheel keyed on its one end, actuated by a small pinion on the free end of a
short longitudinal shaft revolving in bearings formed in brackets secured to
the end pipes or chests, and driven in one direction by a winch handle or by
a fly wheel with a handle when it is desired to actuate the scrapers by hand;
but when it is desired to actuate them by motive power a simple open belt
is passed over a fast-and-loose pulley on one end of the short driving pinion
shaft from any adjacent prime moving shaft.
By another arrangement a worm or screw wheel is keyed on one end of
the long shaft, actuated by a screw working in it fast upon a short transverse
driving shaft, also carried in bearings formed in saddle or other form of
brackets bolted to the end pipes, and this short screw shaft is driven by an
open and cross belt passed over two loose pulleys mounted on it, and a fast
pulley between them from any adjacent prime moving shaft, or instead of the
fast pulley a reversing clutch may be placed between the two loose pulleys,
driven in reverse directions by the open and cross belts; or otherwise, the
clutch may be placed between two loose bevel pinions on the transverse shaft,
working into corresponding clutches formed on their inner faces (the worm
and worm wheel in this case being dispensed with); the two pinions are geared
into the reverse sides of a large bevel wheel keyed on the end of the long shaft,
and the clutch and transverse shaft may cither be driven by a belt or chain
passed round the central part of the coupling clutch itself, or a seperate belt
or chain pulley keyed on the shaft for that purpose from any adjacent primo
moving shaft. A sliding rod which works in guides formed in arms projecting
from brackets carrying the screw shaft, and made either to carry belt forks or
to work a clutch fork, is pushed to and fro by a vertical weighted and tilting
lever, to which it is attached by a link or slot connection so as to shift cither.
a reversing clutch, or one or other of the driving belts into gear according as
it is the clutch or fast pulley which is placed between the loose driving
pulleys, either of which arrangements reverse the motion of the screw and
longitudinal shafts, so as to raise all the sets of scrapers ranged along each
side of the shaft alternately to the top of the pipes, and as they reach the top
a stop on one of their chains at each side, or on the spindles to which the ends

page_text: of that chain are attached, comes in contact with one or other of the arms of
a duplex lever or beam keyed on the same spindle as the vertical tilting lever,
which is thus brought up a little past the plumb by the rising of the scrapers
and the momentum of the parts; when at this position the weight of the leyer
comes into effect, and tilts it with sufficient force either to shift the belts or a
clutch, and so reverse the motion at every time the scrapers on either side
approach the extreme top end of their traverse. The vertical arm of the tilting
lever is furnished with a catch or retaining horizontal weighted lever, having
two recesses formed at the proper distances apart to take in or upon a small.
antifriction roller carried on a laterally projecting stud in the vertical lever
at its extreme tilted positions on either side, so as to retain it there from
going further one way or the other until the pressure of the stop on the rising
chain or stem of the scrapers begins to press it up to the vertical position, and
at this part near the centre of the catch bar a larger antifriction roller is
carried on a stud projecting laterally from it, which by its revolving and wedge
action and weight of the lever, as the small roller of the vertical lever is pushed
under it, materially assists the vertical lever over the dead vertical centre in
the direction it was being moved by the raising of the scrapers on the one side
or the other. When the bevel wheel arrangement is employed the reversing
clutch is shifted direct by the tilting weighted lever through a stud or fork.
projecting out from it, and working into a groove in the clutch, and in place
of the lever being tilted by the duplex lever, and the rising of the chains as
herein described, it is also in some cases preferred to do this by two lateral
studs projecting from the face of either the screw or the bevil wheel, which as
they come round are so set as to act on a small cam or tappet surface, or anti-
friction roller carried by the lever, as to reverse or tilt it at the proper time
and position when the scrapers are near the top and bottom of their strokes.
up
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Joseph Twibill in the Great Seal Patent Office on the
14th March 1867.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOSEPH
TWIBILL, of Irvine, in the County of Ayr, North Britain, Engineer, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fifteenth day of September, in the year of our Lord
One thousand eight hundred and sixty-six, in the thirtieth year of Her

page_text: reign did, for Herself, Her heirs and successors, give and grant unto me,
the said Joseph Twibill, Her special licence, that I, the said Joseph
Twibill, my executors, administrators, and assigns, or such others as I, the
said Joseph Twibill, my executors, administrators, and assigns, should at
any time agree with, and no others, from time to time and at all times
thereafter during the term therein expressed, should and lawfully might
make, use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN STEAM GENERATORS OR BOILERS, WATER HEATERS, AND
APPARATUS CONNECTED THEREWITH," upon the condition (amongst others) that
I, the said Joseph Twibill, my executors or administrators, by an instru-
ment in writing under my, or their, or one of their hands and seals, should
particularly describe and ascertain the nature of the said Invention, and in
what manner the same was to be performed, and cause the same to be filed in
the Great Seal Patent Office within six calendar months next and immediately
after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Joseph Twibill, do hereby declare
the nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement in writing, reference being had to the accompanying Drawings,
and to the letters and figures marked thereon, that is to say :-
My said Invention, which may be judiciously specified under two heads, has
reference to new or improved additions to steam generators or boilers and
water heaters of the ordinary forms and constructions now in general use, and
particularly those with large open flues, and also to a considerable extent to
that of my improvements upon or in connection with those forms and con-
structions of steam boilers and water heaters forming the essential part of the
Invention for which Royal Letters Patent were granted to me on or about
the Twenty-seventh day of January, One thousand eight hundred and sixty-
five, and numbered 243, and which improvements render such steam gene-
rators or boilers and water heaters much more economical and efficient than
as heretofore constructed,
And in order that my said Invention may be properly understood and per-
formed or put into practice, I will now proceed to describe the several
illustrative Figures upon the Sheet of explanatory Drawings which I have
hereunto appended for the purpose of showing the best modifications and
means which I am at present aware of for carrying out my said Invention or
improvements into practice, the same reference letters and figures being
employed to indicate the same or similar parts in all the Figures.

page_text: Figures 1 to 7 inclusive are sectional views of ordinary forms of round
steam boilers, illustrative of and having applied to them various modifications
of the improvements under the first head or part of my said Invention,
Figures 1 and 2 of which are respectively a longitudinal and a transverse
section of an ordinary horizontal round steam boiler A with two cylindrical
flues B passing longitudinally through it, showing one modification or adap-
tation of my said improvements, and which consists in placing within each of
the two flues B an additional or supplementary heating vessel C of a cylindrical
form filled with small longitudinal tubes jointed into the two close ends or
tube plates of the vessels, which are some inches smaller in diameter all round
than the flues B. These vessels C arc, by preference, placed concentric
within the flues B and near the back end for the convenience of easy access
by the brick flues behind to allow of the inspection, cleaning, or removal of
the vessels when desired, and they are connected at the upper and lower
parts of their ends by the branch pipes D to the upper and lower parts of
the main flues B respectively, so as to form a complete connection for the
currents of water through the vessels all round the tubes with that of the
main boiler, while the flames and heated products of combustion passing
through the flues B from the burning fuel on the fire-grates B¹ pass through
the stacks of tubes in the vessels C and through the annular spaces between
their outer casings and the flues on their way to the chimney, so as to add
great extra heating surface to the boiler A so fitted with the vessels C, and at
the same time cause a thorough current or circulation of the water or water and
steam through the vessels C and boiler A by or through the branch pipes D.
By these improved means I am enabled to utilize the heat of the fuel or its
gaseous products in a more perfect manner than has heretofore been accom-
plished in open flued boilers.
Figure 3 is a sectional clevation of an ordinary form of vertical steam
boiler A', having a large main hollow cylindrical or conical chamber or fluc B
passing up through its centre leading into the chimney B³, shown as fitted
with a supplementary heating vessel C formed and fitted, by preference,
within the upper part of the flue B, in all respects as described in reference
to Figures 1 and 2, so that the heated products of combustion passing up to
the chimney B³ from either a fire-grate placed in the lower part of the
chamber B, or from other fires or furnaces near at hand led into it by flues
formed in the brickwork below the boiler A', pass up through the tubes and
all round the outer circumference of the vessel C containing them, so as to
heat the currents of water and steam generated in the vessel passing up
through the branch pipes D, which attach or joint the vessel to the shell of the

page_text: flue B, small doors being formed in the shell of the boiler A¹ at A² for the
purpose of screwing up or unscrewing the joints of the branch pipes Dat
their attachment to the fluc B². The cylindrical and tubular vessels C may
also be placed in other parts of the main iron flues of the boilers besides
those shown and described, or in the brick flues close to the boilers, or in
parts of these flues formed into hollow cylindrical chambers round the vessels,
and when so placed be connected to the end or lower part of the boiler by
branch pipes, as shown and referred to in regard to Figures 1, 2, and 3,
namely, by having the lower part of the vessels connected to the lower parts
of the boilers, and the upper parts of the vessels to the upper parts of the
boilers. These supplementary vessels C may be made of other transverse shapes
or forms than that of the round form described and shown in these Figures
(1, 2, and 3), to suit the form of the flues into which they are to be fitted,
and they may be made to suit and be fitted to other forms of steam boilers
besides those of the cylindrical and flue boilers, and to other water heaters
also, besides those shown and described in relation to Figures 1 to 7. When
it is desired to place these additional heating vessels C within the brick flues
or chambers connected directly therewith leading from the boilers to the
chimney, I prefer to construct, arrange, and attach them to their respective
boilers by either of the modifications or arrangements shown in the sectional
elevation and plan in Figures 4 and 5 or Figures 6 and 7 respectively, that is, in
sets or "stacks" of tubes E arranged either in vertical or horizontal transverse.
parallel rows in the form of a rectangular vessel C¹, having the water circulating
through the inside of the tubes E, by their all being tightly jointed by means of
turned and bored spigot and faucet joints, or when desired by flanged joints at
both their ends to the shallow or narrow close chests F, having jointed lids F
on one side to allow of free access thereto for the purpose of withdrawing or
inserting the tubes E, or forming their joints when desired, the whole forming
the portable supplementary vessels C', as shown in the Figures 4 to 7, placed
in the chamber or flue G at the back end of the boilers A (part of which are
shown in these Figures), where the two flues B drop down into the main
return flue H, so that all the hot gases from the furnace impinge on the outer
surface of the set of tubes E, so arranged in the chamber G (which may
either be formed of sheet iron with doors G' at the back, Figures 4 and 5, or
in the brickwork with a door G' over the top, Figures 6 and 7,) as to allow
of easy access to the said vessels. The vessels C¹ in both these arrangements
being attached at the upper and lower parts of their chests or chambers F by
the branch pipes D' to the main boiler A, so as to complete the circulation of
the water and steam through the vessels with that of the boiler by means of

page_text: the branch pipes D', as described in relation to Figures 1, 2, and 3, it will
be obvious that these supplementary heating vessels C, C¹, will require to
be of various shapes and sizes to suit the particular shape or form of the boiler
and flues to which they are to be fitted, and the judicious choice of their
position will to some extent depend on the form and arrangements of the flues
in the boilers or brickwork. But what I have described and illustrated in
reference to Figures 1 to 7 inclusive will sufficiently show the sizes and
arrangements which I find to answer best for such a boiler as that shown in
Figures 1 and 2, and be sufficient guide to a practical engineer for working
out the first part of my Invention in practice generally, and also for other
forms of boilers than those shown in these Figures 1 to 7; simply premising
that for smaller boilers I would generally reduce the size of the vessels as
regards their widths and heights or numbers of their tubes; but I would not
reduce the lengths of the vessels or tubes much, or nearly in the same ratio as
the size or cubical contents of the boilers, so that their length might thus in
particular cases vary from one-sixth to three-fourths of the whole length of the
boiler to which the vessel was to be fitted. In the modifications of supple-
mentary heating vessels in which the heated products of combustion are made
to act upon the outer surface of the sets or "stacks" of tubes or pipes, such as
shown and described in regard to Figures 4 to 7 inclusive, I employ scrapers
mounted upon the pipes in sets so as to move to and fro upon the pipes, and
thus by their action on the pipes keep their surface always clean for the
more perfect conduction of the heat.
The improvements under the second and last head of my said Invention
have reference to now or improved forms or constructions of the said scrapers,
and to mechanical arrangements of mechanism or apparatus for imparting a
reversing and reciprocatory action or motion to a number of these sets of
scrapers mounted upon the "stacks" of parallelly arranged tubes of these
supplementary heating vessels; but which scrapers and mechanism are also
equally applicable for scraping and actuating the scrapers upon the pipes of
the steam boilers and water heaters constructed in accordance with the heroin-
before mentioned Invention for which Royal Letters Patent were granted to
me, numbered 243, and dated the Twenty-seventh day of January, One thou-
sand eight hundred and sixty-five, and also for the scraping and actuating the
scrapers of the pipes of other such boilers or water heaters in which the pipes
are arranged in a nearly parallel manner to each other. My improvements
under this last head, when applied to a "stack" of vertically arranged tubes E¹
(of such vessels as I have herein referred to as suitable for the application
of these improvements), consist of round rings or plates of iron with circular

page_text: or semicircular holes or recesses in them encircling the pipes E, arranged by
preference in square or rectangular sets of twelve, sixteen, twenty, and thirty,
formed in rows of three by four, four by four, four by five, and five by six, all
as shown at a, b, c, and d respectively in the plan diagram, Figure 8, and in
duplicate parallel transverse sets at a', b', c¹, and d¹ on the opposite sides of
the central longitudinal shaft o, for actuating the set of scrapers to be herein-
after more fully described, running the whole length of the sets of pipes E¹
forming the whole "stack" or vessel, which circular scrapers e, as shown in
detached face view, Figuro 9, and the general arrangement of the said scrapers
in duplicate sets as. referred to in relation to Figure 8, and other forms of
scraper not hercin mentioned, and moved in duplicate sets as the pipes aro
arranged for that purpose irregularly, are not new, but have heretofore been so
used and arranged.
Figures 10, 11, 12, 13, and 14 are face views of five of my new or improved
forms or constructions of scrapers, and Figures 15 to 25 are partial elevations,
horizontal, and sectional views of vessels, which answer either for boilers or
water heaters, formed of sets of parallelly arranged tubes or pipes E', embodying
and illustrative of my improvements in carrying and actuating either the
scrapers at present in use or my said new or improved scrapers. Figures
15, 16, 17, are each respectively a side elevation, an end elevation, and a plan
of one arrangement embodying these improvements as applied to such a vessel,
composed of a stack of 96 pipes E¹ vertically arranged in three double
sets b, b¹, of 16 pipes in each single set, and showing particularly one modifi-
cation of my new or improved mechanism for giving the necessary reciprocating
and reversing motion to the whole, in this case six sets of scrapers, into
which the whole set or "stack" of pipes are divided.
Figures 18 and 19 are a partial clevation and plan of another arrangement
of the mechanism for working the scrapers of a similar vessel to that shown in
Figures 15, 16, and 17, and illustrative of the mode of arranging and fitting
the scrapers to the pipes thereof to be scraped or cleaned.
Figures 20, 21, and 22 are respectively a horizontal section, an edge view,
and a sectional edgo view to a large scale (corresponding to that of the
detached views of the scrapers, Figures 9 to 14), showing one mode of fitting
one of my new forms of scraper to one set of 16 pipes; Figure 23 is a
detached elevation of another mechanical actuating and reversing motion
for giving reciprocating motion to the scrapers of such vessels; and Figures 24
and 25 are side elevations of arrangements for reciprocating the scrapers of
such vessels, more particularly suited for those having their tubes or pipes
ranged in a horizontal or angular transverso direction.

page_text: When the ring e, square plate with round hole f, or the plate g, with the
two semicircular holes cut out of its two opposite sides, are used as scrapers
I use a strong longitudinal or transverse bar or frame h, shown clearly in
Figure 19, passed in at the centre space of the set of 16 tubes or pipes,
and then turned down to a plane at right angles to the pipes on which the
scrapers are to work, having lateral arms h¹ projecting out from each side of
the centre bar h through between each double pair of pipes E', so as to carry
or move each of these small scrapers e, f, or g upon the pipes. Over the
scrapers g¹ and across the arms h', between the two outer rows of pipes E',
parallel to and on each side of the centro bar h, I bolt two guard plates i,
having short lateral arms over the scrapers to hold them in position by the
screw studs or stop pieces i between the frame and guard i, rather deeper
than the scrapers, to allow them to move freely laterally to suit any irre-
gularities in the pipes if not quite parallel to each other, but not so loosely as
to allow the scrapers to fall to such an angle as to become tight or jammed
while being moved up and down or to and fro upon the pipes E' to scrape
them by the action of the frame and guards i, through the strong stems j
or firmly attached or secured to the centre of the frame h, actuated by an
endless chain k or rack and rack wheel 1, 1, to be hercin-after more fully
described.
In some cases the outer arms h³ may be made longer than the others, so
that extra bars parallel to the bar h may be attached for additional single or
double rows of pipes extending beyond the arms h', having short arms pro-
jecting laterally between the pipes to carry their scrapers, in the same way
as the bars h¹ carry those of the pipes E, shown in Figure 19. In this Figure
is also shown the general arrangement of the several scrapers e and fin red
lines, and g and g' in black lines, as placed in the moving frames h, which
when the long scraping plates g' are employed do not require more than the
three duplicate lateral arms for carrying these long plate scrapers g' or g³.
The long plate scrapers g² are shown as placed in a proper working position
on their carrying and moving armed frame h³, h', Figures 20, 21, and 22, and
in under face view detached in Figure 13. The scraper 9', Figures 12
and 19, is a long flat cast or malleable iron plate extending cross the whole
row of pipes E' longitudinally or transversely, with semicircular recesses along
each side to embrace half the circumference of the row of pipes on each side
of it or them when the whole set are placed in working position. One or
more of these plates g¹ may be directly attached to a guiding or actuating
rod, and either worked by handles and manual power, as shown at m in
Figures 6 and 7, or the rods m could be worked by motive power, when

page_text: desired, by a modification of some of the mechanical movements, to be herein-
after described in reference to Figures 15 to 25, for actuating these various
scrapers.
Another modification or form of this long scraper with semicircular recesses
for embracing one-half of a whole row of the pipes E is shown detached at g³,
Figure 13, and in plan or face view, Figure 20, as placed upon the duplicate
three-armed frame h and h³, for carrying and working these scrapers g³ in sets,
and Figures 21 and 22 are an edge view and sectional edge view of the same
corresponding to Figure 20. In this arrangement the scraper g' is much the
same as one-half of that shown at g¹ cut down the centre of its length. Two
of these scrapers g² encircling one row of pipes have their adjacent edges
bevelled so as to overlap each other and scrape round the circumference of the
pipe at the joint, having short feet or rests n at this part on their under side,
while at their back edges and ends they have bevelled parts resting and acting
on wedged-shaped pins or surfaces indicated at n', so that as the hollow scraping
surfaces wear away the weight of the scraper acting on the wedge or angled
surfaces n¹ of their own back corners, and the projecting pins tend to keep
them always up against the pipes so as to scrape them properly when raised
and lowered for that purpose. A simpler form of this modification of scraper
is shown detached in side view at g³ in Figure 14, formed out of a square bar
of malleable iron bent to the proper shape to encompass half the circumference
of the row of pipes, and having short arms at the ends projecting backwards
and forward with bevelled surfaces on their under sides and ends at n² for
the like purpose, as described in reference to the former modification g³, of
keeping the scraping surface always up against the pipe. In the use of the
several arrangements of long scrapers g', g, and g³, the guards for holding them
in proper working position are simply formed by the two iron bars i², bolted
a slight distance clear of and over and across the whole of their ends by the
bolts to the outer arms 2 of their moving and carrying frame h, as shown
more particularly in Figures 20, 21, and 22, the slight clearance between the
scrapers and their guards allowing of their free action upon the pipes in
scraping. Referring to Figures 15, 16, and 17, the scrapers e are arranged
in parallel rows, all fitted and attached to their moving frame h and stems j
and, one on cach side of their main actuating and reversing shaft o, carried
in bearing brackets o', bolted to the chests F or cross pipes at the ends of the
main parallel pipes E or 6, 61, as the case may be, indicated also in the general
diagram, Figure 8, before named, so as to work in pairs transversely up and
down by a single chain k passed over a chain wheel ¹ for each double set of
scrapers, the two ends of the chain k being attached to an eye in the stems j

page_text: and j'in the centre of the frames h, carrying the scrapers acting and surrounding
the sets of pipes 6 and 6' respectively. As the three chain wheels ¹ are
keyed to the shaft, and the chains k work over them by stiff friction or by
notches in the same manner as pitch chains, the turning of the shaft o in
one direction raises the three sets of frames and their scrapers e of the
one whole set of the tubes b on the one side of the shaft, and lowers all those
on the pipes on the other side, and vice versa; when the shaft o is
turned in the opposite direction it raises all the scrapers on the pipes 6',
and lowers all those on the sets of pipes 6 ranged on the other side of the
shaft o. Instead of the chains k and chain wheels k¹, the two racks and
toothed rack wheel (Figure 24) may be judiciously employed, particularly
when the ranges of pipes and on each side of the shaft o, forming the
heating vessel, are laid in a horizontal position, as shown in Figure 24, or
placed in an angular position, and when this arrangement is employed for the
sets of long pipes 6 and 6¹ I prefer to mount two sets of frames and scrapers
on each set of pipes, coupled as shown at 2 and 3, worked by the racks 1, 1,..
so that the scrapers, rack, and rack wheels have only to travel through half
the length or space they would otherwise require to do if there was only one
sot of scrapers mounted on the pipes to scrape the whole surface length of the
pipes and . In some cases when the sets of pipes b, b', are disposed in a
horizontal or angular position I prefer to mount a shaft o² at the opposite side
or ends of the tubes, fitted and ranged with chains and chain wheel
all respects similar to that connected with the shaft o, at the other side the
ends of the chain k being attached to stems on the back of the frames of
the sets of scrapers, except that these chains and wheels being only for trans-
mitting motion from the one set of scrapers to the other (when directly pulled
by the chains k of the actual driving chain wheel ' on the shaft o); the shaft
may either run loose in its bearings, or the wheels k may run loose on the
shaft; the action being as follows, namely, that when the shaft o is turned
in one direction, so that the chain & pulls all the scrapers to that end upon the
pipes & nearest the shaft o, it also at the same time, by the action of the back
transmitting chains passed over the chain wheels k³ of the shaft os, pulls all
the scrapers on the pipes to the opposite end of their pipes nearest the
shaft o, and vice versa; the turning of the shaft o in the opposite direction
pulls all those of the pipes b to the side nearest itself, and by the chains k
and the back chains draws all the scrapers of the pipes b' to the end of the
pipes nearest the shaft o; thus the driving and reversing action or motion of
the shaft o in all these my improved arrangements for working the scrapers
of steam boilers and water heaters constructed of parallelly arranged pipes
in

page_text: generally draws or reciprocates all the scrapers alternately from one end of
the pipes to the other, so as to clean or scrape them regularly or inter-
mittently, accordingly as the shaft is so actuated either by hand or motive
power. The driving and reversing of these long shafts o, so as to produce the
said necessary reciprocatory action of the sets of scrapers, is effected under one
arrangement, as indicated in Figure 25, by a mangle wheel p keyed upon it
either at one end or towards the centres when the shaft is long, actuated or
driven by a small pinion on the short longitudinal shaft p', revolving in bearing
brackets q, screwed to the cnd chests F, when such are used, as in Figures 4
to 7, or to the end connecting pipes q', when these are used, as in the several
arrangements, Figures 15 to 25. When it is desired to actuate the scrapers
by hand, the shaft p' is driven in one direction only by either a winch handle
or by a fly wheel with a crank handle in it fast on the shaft; but when they
are to be actuated by motive power a fast-and-loose pulley are mounted on
one end of the shaft p, furnished with a shifting fork for putting off and on at
pleasure a single belt passed round them from a pulley on any adjacent prime
moving shaft for the purpose.
By another arrangement, Figures 15, 16, and 17, the shaft o is actuated
and reversed, so as to reciprocate the scrapers by the screw or worm wheel r
keyed upon it at one end, or when the shaft is long keyed on it near the
centre of its length, driven by the screw 7 working into it fast on the short
transverse driving shaft 8, revolving in bearings formed in the two saddle or
other form of brackets t, bolted to saddles or flanges formed on the end
pipes q. The screw shaft 8 is driven by an open and crossed belt passed over an
arrangement of two loose pulleys &¹, 81, and fast pulley & between them from
any adjacent prime moving shaft for the purpose, all mounted and arranged
in the usual manner upon the shaft, with a reversing and stopping sliding
rod u carrying the forks embracing the belts, and working in guides or slots
formed in the brackets t. The sliding rod " is moved to and fro by the
vertical tilting weighted lever oscillating on a stud or spindle v² in the fixed
bracket v² connected to it by the link ¹, or other equivalent connection, such
as a slot and pin, to compensate for the radial action of the lever v, the
tilting of which is effected in this arrangement by the two studs 1 and 2 pro-
jecting laterally from the face of the screw wheel ", with antifriction rollers
on them, which act on the arm of the lever, or on a friction or cam surfaco
on it provided for the purpose; as the scrapers come near the end of their
upward stroke on either side, so as to raise the weighted lever o a little past
the vertical position when it tilts over, and by the force of its weight in falling
shifts the slide u and driving belts on the pulleys 81, 8¹, and s², and thus

page_text: P
reverses the action of the screw shaft 8, screw 71, and screw wheel r, which
by the other stud 1 or 2, as the case may be, coming round in the opposite
direction tilts the lever to the reverse side as the whole set of scrapers on the
rising side come near the end of their stroke, so as to again reverse them in
time to descend before quite reaching the top, and thus alternately raises the
whole of the scrapers on each side of the shaft o, so as to keep the surface of
the pipes and 6¹ clear as desired; and when not required to be in motion
the lever can be fixed in a vertical position by a sliding or hinged notch to
embrace it, so as to retain the two belts running on the two loose pulleys
81, 8', while two pins in the sliding rod at a retain the belts and lever vin
their extreme reversed position for the time being with a spring catch when
desired. To assist the lever faster over the vertical point on either side as
it is brought up to this position by the two studs 1 or 2, I in some cases,
when it is preferred that the screw shaft should be moved constantly and at a
very low speed, employ a stud and antifriction roller 4 on the lever v, which as
they come round towards the plumb or vertical central line the roller 4 comes
bencath another antifriction roller 5 on a stud projecting laterally from a
weighted lever 6, shown in red lines in Figure 16, fulcrumed on one of the
brackets t, so as to raise the lever 6, when the moment the roller 4 passes tho
centre line the extra force of the weighted lever 6 and wedge action of the
rollers 4 and 5 forces over and tilts the lever at this point when its own
weight has little force to do so. Two semicircular notches may also be mado
on the under side of this weighted tilting and catch lever 6 to take on to a
stud or on to the roller 4 of the lever v, so as to hold the lever until the
reversing studs 1 or 2 again come round to lift the lever v.
In Figure 23 is shown a different modification of my improvement for
actuating and reversing the motion of the screw shaft & from that shown in
Figures 15, 16, and 17. In this arrangement a reversing clutch w is mounted
on the shaft 8, sliding with a groove and feather connection between the two
slack pulleys s' and 8¹, driven in reverse directions with open and cross belts;
thesc pulleys having corresponding clutches formed on their inner sides, into
which the sliding clutch or coupling box w takes when pushed towards the
pulleys. The coupling box w is thus shifted so as to take into either of these
clutch boxes on the side of the pulleys & and s by the vertical gab lever 10',
connected by the link or rod u to the tilting lever v, which is reversed and
tilted in this case as described in reference to Figures 15, 16, and 17, and
thus accordingly reverses the screw shaft 8, and through it the longitudinal
shaft o, so as to simultaneously raise all the scrapers ranged on one side of

page_text: the shaft and lower all those on the other, and vice versa alternately, as
hcrein-before described.
Another arrangement of this clutch coupling mechanism for actuating tho
shaft o in the reverse direction as herein-before described is shown in elevation
and plan, Figures 18 and 19 respectively, and it consists in substituting for
the screw wheel and screw a bevel wheel x keyed on the shaft o, actuated
by either of the loose bevel pinions or when put in motion by the
clutch coupling box to taking into a corresponding clutch on the inner faces
of the bevel pinions. The pinions and coupling box are in this case mounted
on the central part of the shafts in place of the screw r, raised in a plane
with the axial line of the shaft o, and the shaft & may either be driven by a
chain or belt passed over a chain or belt pulley on the reversing clutch w,
or otherwise on a separate fast pulley for the purpose, as indicated at y or y¹
respectively, and the clutch may be shifted from one side to the other, so as
to actuate either of the pinions and reverse the motion of the bevel wheel x and
shaft o by either the simple tilting lover v, in this case fitted with a chuck
fork actuated by studs 1 and 2 placed in the face of the bevel wheel x, instead
of the screw wheel r, all as described in reference to Figures 15, 16, and 17,
or otherwise by lowering the fulcrum v¹ of the lever carrying the gab fork
for shifting the coupling, in this case lettered ³, and keyed on the end of a
light shaft v', having a duplex armed lever z, z¹, on its other end below one
of the chain pulleys, having an open end with the chains on each side passing
up through them, so that as the scrapers rise on the one side or the other
to the top of their stroke the end of the stem j or j' of the frames carrying
the scrapers or a pin or stop upon their chains comes in contact with the
corresponding end of the lever z or z¹ so as to tilt it, and thus reverse or
bring the lever vs a little past the vertical line. When the motion is slow
I in some cases prefer to put a short segmental rack on the upper end of the
reversing lever v³, and gear a small pinion fast on the fulcrum of the tilting
weighted lever v* carried on a fixed stud as a fulcrum, so that when the levers
are brought up to the vertical line by the slow motion of the scraper frame
and duplex lever arrangement the weighted lever comes into action with
great power and leverage, so as to complete the reversing of the clutch by the
pinion and rack on these levers ³ and ot, and thus reverse the action of the shaft o
alternately as the rows of scrapers rise to the top on each side of the shaft o.
Having now described and particularly ascertained the nature of my said
Invention, and the manner in which the same is or may be used or carried
into effect, I may observe that I do not confine or restrict-myself to the

page_text: precise details or arrangements which I have had occasion to describe,
delineate, and refer to, as many variations may be made therefrom without
departing from the main or essential features of my said Invention, neither do
I claim the forms of the various parts particularly by themselves or their
construction or the modes of jointing and putting them together, which I have
had occasion to describe or refer to, as many of these have heretofore been
used in various mechanical structures, except in combination with and forming
part of the essential features of my said Invention; but what I consider to be
novel and original, and therefore claim as the Invention secured to me by the
herein-before in part recited Letters Patent is,―
First. The application and use of additional portable tubular heating
vessels to steam boilers and water heaters generally, substantially in the
improved manner, and for the purposes herein described and shown in
reference, to Figures 1 to 7 inclusive of the accompanying Drawings
under the first head or part of my said Invention, or any mere modification
thereof.
Second. The forms and constructions of scrapers and their holding and
actuating frames, together with the various arrangements of mechanism for
actuating the same, for the purpose of scraping the outer surface of the pipes
or tubes of steam boilers and water heaters composed of sets of such pipes
disposed nearly parallel towards each other, and having the heated products of
combustion acting on their outer surface, all substantially in the improved
manner herein described and shown in reference to Figures 11 to 25 inclusive
of the accompanying Drawings under the second and last head of my said
Invention, or any mere modification thereof.
In witness whereof, I, the said Joseph Twibill, have hereunto set my hand
and seal, this Thirteenth day of March, in the year of our Lord One
thousand eight hundred and sixty-seven.
0 Witness,
W. R. M. THOMSON,
Patent Agent,
20, Buchanan Street,
Glasgow.
JOSEPH TWIBILL. (L.S.)