Improvements in Water Tube or Tubulous Boilers.
Year: 1893

page_text: The decision of the Comptroller-General, of the 15th day of June 1895, allowed,
under Section 18 of the Patents, &c. Act, 1883, an Amendment of this
Specification.
Date of Application, 7th Dec.. 1893
Complete Specification, Left, 27th Aug., 1894-Accepted, 7th Jan., 1:95
PROVISIONAL SPECIFICATION.
Improvements in Water Tube or Tubulous Boilers.
I, ERNEST PETERSEN, of Kertch, Crimea, Russia, Engineer, do hereby
declare the nature of this invention to be as follows:-
My invention relates to that class of water tube or tubulous boilers in which
water chambers arranged on each side of a fire grate are connected to a separate
water and steam chamber above the fire grate by a number of water tubes of small
diameter placed close together, so as to offer a comparatively large amount of
heating surface to the flames and combustion gases which pass transversely through
the interstices between such tubes on their way to the uptake.
My present improvements have mainly for their object to obtain a very greatly
increased amount of heating surface in the said water tubes as compared with the
constructions of such boilers as heretofore proposed, while very greatly reducing
the number of joints required to be made between the water tubes and the water
chambers, in addition to which a great number of further advantages are obtained
thereby.
For this purpose I adapt the construction of compound tubes described in the
Specification to my Patent No. 13238 of 1890 to the construction of water tube
boilers in the following manner : secure a group of small tubes, preferably
seven in number, to a disc or cup at each end in a similar manner to that
described in my said Specification, but instead of making these cups of cylindrical
form, adapted to be fixed in the tube plates of ordinary tubular boilers, I forin
them as a closed receptacle, terminating at one end in a tube of comparatively
small diameter, thus forming a compound tube terminating in single tubular ends.
The extremities of these tubular ends 1 fix respectively in the water chambers
situated at the side of the fire grate and in the upper water chamber, so that
the space over the fire grate is enclosed by any desired number of these com-
pound tubes arranged side by side and in several rows one behind the other,
with small spaces intervening between them. The cup tubes at the upper ends
are only of sufficient length to pass through the shell of the upper chamber so
as to be secured therein by screw nuts, but the cup tubes at the lower ends
are made of such a length that the part which is composed of the group of small
tubes is limited in length to the space which is within the effective line of
draught of the furnace, so that the useless extension of such small tubes beyond
the line of draught, which only adds weight to the boiler, without increasing its
effectiveness, as in boilers of present construction, is done away with, being
replaced by the single tubes of the lower cups. Instead of providing each
compound tube with a separate lower feeding tube, I in some cases unite two or
more of the cup tubes to a single feeding tube; so that I still further reduce
the number of joints to be made between the feeding tubes and the water
C

page_text: chambers, and by making such connection of the united cup tubes and the
feeding tubes with a screw union, I am enabled to detach and remove each separate
compound tube and replace it with a new one when required with the greatest
facility. It will be seen that by the above described construction of such
water tube boilers a greatly increased tube surface is obtained as compared with
the present construction of such boilers, since the small tubes can be placed
very much closer together, owing to the fact that they are shrunk into the
comparatively thick cup surfaces instead of being fixed in the comparatively thin
shells of the upper and lower chambers by screw nuts which latter arrangement
necessarily requires sufficient plate surface to be left between the contiguous tubes
to afford the room for the nuts and to leave the shell of the chamber of sufficient
strength.
Owing to the very large saving in useless lengths of small tubes there is also a
great reduction of cost in the construction of these boilers, in addition to the before
mentioned saving in weight, which in torpedo boats and other small vessels is of
considerable importance, while owing to the greatly increased amount of heating
surface afforded, such improved boilers of considerably smaller dimensions than
those now employed will afford a greatly increased steam power.
A further advantage arises from the fact that I am enabled to make the groups
of small tubes of copper instead of iron or steel, while the cup tubes are of iron or
steel, thus obtaining a much more rapid absorption of the heat by the groups of
tubes than when these are of iron or stee! as heretofore.
Suitable shields or baffle plates are provided at the backs of the lower cups of
the compound tubes for preventing the furnace draught from escaping through the
comparatively open spaces in which the lower cup tubes are situated.
The sides of the boiler behind the water tubes may be enclosed by covers, which
I prefer to form partly of pipes through which the air supply for the forced
draught for the furnace is made to pass, whereby such air becomes heated while
the outer surfaces of the boiler are kept comparatively cool. This arrangement is
also applicable to water tube boilers of present construction.
It will be understood that the above described construction of compound tubes
with single cup feeding tubes may also be employed in other constructions of steam
boilers than that described, whether entirely tubulous or not.
In the above described construction of water tube boilers with a water chamber
on each side of the furnace and a water and steam chamber above the same, I
support the latter by strong stay tubes of large diameter from the lower water
chambers, and I support the uptake and chimney by the upper steam and water
chamber by means of trussed saddle pieces fitting the curved upper surface of
the steam chamber, the before mentioned side covers being also loosely hung
from the hook shaped extremities of the saddle pieces, so that they can be readily
removed.
The lower water chambers also rest on suitable saddle pieces formed on a base
plate extending across beneath the fire grate.
Dated this 7th day of December 1893.
ABEL & IMRAY,
Agents for Applicant.
Improvements in Water Tube or Tubulous Boilers.
1, ERNEST PETERSEN, of Kertch, Crimea, Russia, Engineer, do hereby
declare the nature of this invention and in what manner the same is to be 5
performed to be particularly described and ascertained in and by the following
Statement :-
'
My invention relates to that class of water tube or tubulous boilers in which

page_text: water chambers arranged on each side of a firegrate are connected to a separate
water and steam chamber above the firegrate by a number of water tubes of small
diameter placed close together, so as to offer a comparatively large amount of
heating surface to the flames and combustion gases which pass transversely through
the interstices between such tubes on their way to the uptake.
My present improvements have mainly for their object to obtain a very greatly
increased amount of heating surface in the said water tubes as compared with the
constructions of such boilers as heretofore proposed, while very greatly reducing
the number of joints required to be made between the water tubes and the water
chambers, in addition to which a great number of further advantages are obtained
thereby, that will presently be referred to.
The invention consists mainly in substituting for the separate small tubes
which, in existing water tube boilers, connect the lower water chambers to the
upper water and stean chamber, groups of tubes somewhat similar to those
described in the Specification to my Patent No. 13238 of 1890 but whose ends.
instead of being secured in open cups as there described, are secured in closed
cups or chambers from one of which a single tube extends down to the lower
water chamber of the boiler while from the other a single short tube or neck
passes through the upper steam and water chamber and is secured on the inside by a
screw nut. By this arrangement the following advantages are obtained over the
existing constructions. In the latter the number of separate tubes that can be
grouped together on each side of the boiler is limited by the distance which it is
necessary to keep their ends apart where they are fixed to the upper and lower
water chambers, in order on the one hand to afford the requisite room for the
screw nuts or other means of fixing and on the other hand to retain sufficient
strength in the walls of the water chambers to withstand the steam pressure.
With the improved constructions, as there is only one connecting tube to every
group of (say) seven heating tubes, there is no such limitation to the closeness to
which the tube may be brought together and as a result more than double the
number of heating tubes could be brought into the space which the single tubes
occupy in existing constructions. Again, with existing constructions a great
proportion of the length of most of the water tubes, namely from their connection
with the lower water chamber upward, is out of line of the draught of the furnace,
and is therefore useless for raising steam, constituting so much useless expenditure
and dead weight.
With my improved construction, there being only one connecting tube to every
group of seven or more heating tubes, such length of tubing that is not effective
for raising steam, is reduced to one seventh, or less, of that of present
constructions.
These are the main advantages of my improved construction, but, as before
stated, there are numerous others, resulting from the general construction of the
boilers, which I will proceed to describe with reference to the accompanying
drawings in which Figure 1 shews a part end elevation and part transverse section,
Figure 2 a side view, Figure 3 a plan, Figure 4 horizontal section on line X X
Figure 1, Figure 5 a cross section on line YY, Figure 6 a cross section on
line ZZ, Figures 7 and 8 enlarged sections of the cups and heating tubes.
Figure 9 shews a part section at W. W.
The boiler as here represented is arranged to have its furnace served at the one
end only, it may however be served from both ends.
A is the firegrate, which may be of any known construction. On each side
hereof is a tubular water chamber B B while at a suitable height above it is the
water and steam chamber C. The chambers B are connected to the chamber C by
means of groups of water tubes D secured at each end in cups E E' of which the
outer cups E are secured by a screwed joint to tubes F, the lower ends of which
are connected to the lower water chamber B, while the inner cups E' pass with
their necks through the sides of the chamber C and are secured inside by means of
screw nuts I and washers J J'. There are shown provided 5 horizontal rows of

page_text: these tube groups on each side of the furnace, but there may be any greater or less
number of such rows, the length of the tubes D between the cups E E¹ being
varied in the different.rows as shewn so that the whole of the same come within
the effective draught of the fire, and it will be seen that each row is arranged more
or less at right angles to the direction of the draught, so that they are in the most
effective position for taking up the heat from the flames.
Of the several rows, the two lower groups which take up the greater part of the
heat from the flames, are connected separately by their connecting tubes F to the
water chambers B, while the upper three groups are all connected to branches on
one and the same connecting tube F. For the attachment of the connecting tubes,
the cylindrical water chambers B are formed with three longitudinal broad
ribs B¹ B¹ B', having passages, at distances apart corresponding to the distance
apart of the successive connecting tubes of each row, these ribs being in such
positions that the one for the tubes F of the upper three rows is at top, whilst
those for the tubes F of the two lower rows are arranged below, the object of this
being to allow of the last named connecting tubes being formed with a con-
siderable curvature as shewn, in order to allow of the free expansion and contraction
of the tube groups due to variations of temperature, without straining any of the
connections.
Owing to the fact that there are only three rows of connecting tubes to be
attached to the water chambers B, it will be seen that these can be made of the
smallest possible diameter, consistent with an adequate supply of water to all the
heating tubes, such water being supplied through the large circulating tubes G
that connect the ends of the lower water chambers B with the water space of the
upper chamber C. The water chambers B B are preferably cast, either of gun
metal or of soft steel.
The groups of tubes D are secured perfectly steam tight in their cups E E¹
preferably by shrinking the latter (which are either of cast steel or wrought iron)
on to the ends of the tubes, this being effected by making the holes in the cups
slightly smaller in diameter than the tubes, so that when the cups are expanded by
heating to a red heat, the end of the tubes (cleaned and accurately turned) will
just enter them; on cooling, the cups will then grasp the tubes as firmly as though
they were of one piece. The tubes may either be of steel or of copper or brass ;
by preference I make the two lower rows of steel and the upper rows of copper or
brass. The cups may either be formed conical, or they may be bellied as shewn in
the enlarged section at Figure 7. They may also either be circular for the
reception of seven tubes as at Figure 8, or the flat face may be made square with
rounded corners so as to afford room for nine tubes, the tapering part being kept
conical at the smaller end. The tube groups are made to decrease in length in the
upper rows as the hot combustion gases, in becoming cooled considerably in passing
the lower rows, will decrease in volume, so that a less width is required for the
passage leading to the uptake, the length of the tubes D being strictly limited to
the effective heating space of the furnace, this space being confined by sliding shield
plates H which are slid in between the rows just beyond the outer cups E, being
made to rest upon the connecting tubes F and against the screw union pieces E³.
The longitudinal slits that are thus left between the contiguous plates are also
closed in by means of comb like slotted plates H¹ that are slid in between the rows
and are then dropped with their slots over the union pieces E².
It will be seen that these shield plates protect not only the union pieces E³ but
also the tubes F from immediate contact with the flames and combustion gases, and
as the screwed joints that connect the cups E¹ with the chamber Care inside the
latter and always in contact with water and steam, there are absolutely no tube
joints that are directly in contact with the fire. The screwed joints within the
chamber consist of a nut I, by preference of gun metal, a recessed washer J and
a washer J of asbestos or other suitable material which, by the action of the coned
inner surface of the washer J, is forced not only against the surface of the
chamber C but also against that of the neck of the cup E³, so as to form a perfectly

page_text: steam tight joint, which is in addition assured by the tight fit of the coned surface,
of the cup against the correspondingly coned surface of the hole in C.
As the upper rows of tube groups may be liable to have soot and ashes deposited
between then, I provide them with scrapers K, consisting of plates having holes of
such a size as to be capable of sliding freely backwards and forwards upon the
tubes. These scrapers have rods attached to them that extend outside the
casing so that by means thereof the scrapers can from time to time be slid
backwards and forwards upon the tubes in order to clear them of soot and
ashes.
It will be seen that should at any time one of the tube groups become leaky or
defective, it can be readily removed by unscrewing the connections with the water
chambers B and C; in the case of the three upper tube groups such removal is
facilitated by forming the connecting tube with an oblique flange joint
at F
The tube groups of each row are arranged closely side by side, so that the
cups E E almost touch each other, as shewn at the enlarged section at Figure 7;
by this means the spaces between the contiguous tube group are only slightly
larger than the spaces between the individual tubes of each group, so that the
flames and combustion gases will pass freely in between the latter, and in becoming
repeatedly split up and mixed together in their passage, a more complete combustion
of the smoke and combustible gases will be attained.
A perforated shield X may be provided in the upper water and steam chamber
over the openings of the cup E' E, in order to prevent the water and steam issuing
from these to be projected with too much violence into the chamber, and thus to
prevent priming.
Figure 10 shews a modified arrangement of the connection of the compound
tubes D with the lower water chambers B. The two lower rows of the compound
tubes are connected to the curved branches F F of a tube F fixed with a flange
on a circular boss B on the upper part of the water tube B, instead of each
compound tube being connected by a separate curved tube to the lower part of the
tube B, as in the first arrangement. By this means, while the curved branches F
still allow of the free expansion and contraction of the compound tubes without
straining the joints, the advantages are gained firstly that there is only one joint
with the tube B instead of two, and secondly, this connection being at the top
instead of at the bottom of B, there is no liability of its becoming choked with
deposit.
The bosses B of the tube B alternate with bosses B2 for tubes F connecting the
three upper rows of compound tubes, as in the first arrangement.
Provision may be made for preventing accidents and the stopping of the boiler
on the bursting one or more tubes of a compound tube, as shewn at Figures 11, 12
and 13. At Figure 11 the neck of the upper cup E of the compound tube is
extended beyond the nut I and is formed with a circular edge, on which rests a
valve a guided by an open cap & screwed on to the neck. When the boiler is
working, the valve a is kept open by the upward flow of water and steam from E,
but should one of the tubes D burst, the downward flow caused by the escape of
water and steam will cause the valve a to close down on its seat and thus the
farther escape be prevented.
The escape is in like manner prevented at the lower end by adapting the branched
tube F (Figure 12) of the two lower rows as also the tube F (Figure 13) for the
three upper rows to contain a ball valve e in a seat d so that on the bursting of a
tube, the increased speed of flow of water through F will carry up the ball valve c
so as to close the branch through which the escape is taking place, as indicated by
the dotted lines. One of the branches is made sufficiently large for introducing the
ball through it, and a lining e is then fixed to serve as a seat for the valve.
if
necessary, two ball valves may be provided in the tube, one for each branch.
At Figure 11 is shewn a convenient mode of forming a water and steam tight

page_text: joint between the cups E and the chamber C; it consists in introducing a small
copper ring between the two which, on the screwing up of the nut I, will
constitute a steam- and water-tight packing, thus preventing the necessity for
producing an accurate fit between the coned surfaces of the cup and the
chamber.
The boiler is enclosed by a wrought iron casing L, in which is a removeable ash
pit M carrying the firegrate. The ends of the casing are formed with doors L',
through which access is gained to the tube groups, and for the introduction and
removal of the shield plates, and the tubes are also accessible at the sides; the
plates L being hung at top by means of hooks onto tubular supports N and secured
at bottom by fastenings O, so that on releasing these, the side plates can be
removed.
The tubular supports N, as also the uptake Pinay be carried by trussed saddle
shaped supports Q that rest upon the ends of the upper steam and water chamber C,
this being in its turn carried by the return water tubes G and lower water
chambers B, that are carried on supports R forming the bottom of the boiler casing.
The back end of the latter is by preference constructed as shewn in Figures 5, 6
and 9, namely, as a non-conducting shield S, built up of sheet iron S', and S2 with
an intermediate sheet of glass S³ packed with slag wool or asbestos.
At the inner side of the shield S is a firebrick lining T forming the back of the
furnace, and built up of a number of fireclay blocks, of a shape to fit against the two
side water tubes and the under side of the steam chamber C. These blocks are so
formed that when placed in position they are securely held together by key
blocks T secured by bolts T2 as shewn at Figure 9.
Within this lining may be
arranged a feed water heater U, also formed of tube groups similar to those at D,
through which the feed water is supplied either to the bottom of the upper steam
and water chamber C, or to the lower water chambers.
The sides of the furnace chamber are also formed of fireclay blocks T3 which
extend up to the lower cups E of the first row of tube group.
The forced air supply is also made to pass through tube groups V situated in the
uptake, so as to be heated on its way to the ashpit through the pipes V¹.
Lastly, the steam passing off from the steam chamber C may also be made to
pass through a superheater composed of tube groups W situated in the uptake.
Both these and the tube' groups V are provided with scrapers Y operated by
handles in the same manner as those described in reference to the water
tubes D.
The steam chamber C may either be made plain, cylindrical, or with corrugations
between the tube groups as shewn at Figure 7.
From what has been stated above it will be seen that among other advantages
the following most important ones will be obtained by my improved construction
of water tube boilers, as compared with water tube boilers of present construction.
1. A boiler constructed according to this invention for producing a certain steam
power will be about two-thirds the weight of an ordinary water tube boiler having
the same steam producing power, and it will occupy not more than two thirds the
space occupied by the latter. Thus a boiler of about 9 feet 9 inches height to the
funnel and width of 8 feet 8 inches, will contain 204 tube groups (including feed
heater and superheater) with 1428 tubes of th inch diameter and the steam tubes
will give an effective steam producing surface of 750 square feet, and the weight of
the boiler charged with water will only be about ten tons.
2. It will require only about oue-ninth the number of holes in the water and
steam chambers, and consequently only about one-sixth the number of joints.
3. The joints are all out of reach of the fire or combustion gases.
4. Any tube group of any row can be removed and replaced in a very short
space of time without disturbing the others, which is impossible with the ordinary
constructions; this will also greatly facilitate the removal of scale, as on taking
out a tube group and beating it with a hammer the scale will at once drop off.

page_text: 5. The boiler can be easily taken to pieces and transported to any locality where
it can be rapidly set up and put to work, no brickwork being required. It is
equally applicable as marine and land boilers.
6. In ordinary water tube boilers it is necessary to make the combustion
chamber very small and low in order not to occupy too much room with the
enormous number of water tubes required. With my improved construction owing
to the compact arrangement of the tubes, ample space can be given to the
combustion chamber, resulting in a much greater development of heat and more
perfect combustion.
7. Owing to the possibility of adapting scrapers to the tube groups, which is
impossible with ordinary boilers, they can always be kept free from soot and ashes,
and thus the tube surface always be maintained in the most effective condition for
taking up heat and raising steam.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. In water tube boilers wherein two lower water chambers, situated one on each
side of the furnace grate, are connected to an upper water and steam chamber
above the grate by a number of tubes of small diameter, the use of water tubes
composed of a group of tubes connected at each end to a closed cup or chamber,
the one such chamber being connected by a neck or connecting tube with coned
end surface directly to the upper water and steam chamber of the boiler, while the
other cup or chamber is connected by a neck or connecting tube to a lower water
chamber of the boiler, so that the water circulates from the latter through the cups
and tube group to the upper water and steam chamber while the flames and furnace
gases pass in contact with the tube groups there being two or more rows of such tube
groups one behind the other on each side of the furnace, arranged substantially as
described.
2. In water tube boilers having tube groups such as are mentioned in the first
claim, attaching the one cup of the group to the upper steam and water chamber
by passing the threaded neck of the cup through a hole in the chamber and securing
it by means of an internal screw nut and washer, the coned surface of the cup
serving to form, with or without packing the water tight joint outside the chamber
substantially as described.
3. A compound water tube for water tube boilers consisting of a group of tubes
connected at each end to cups or boxes of conical or ogival shape having at their
large flat end a series of holes for the reception of the ends of the tubes, and at the
small end a tubular neck serving to connect it to other parts of the boiler
substantially as described.
4. A box or cup for a compound water tube such as is referred to in the preceding
claim consisting of a conical or tapering receptacle E having a flat, circular or
rectangular face at the larger end, with a series of holes adapted to receive the ends
of the water tubes D and a threaded tubular extension at the smaller end, adapted
to be secured to the water and steam chambers of the boiler substantially as
described.
Dated this 27th dow of Ano 1901
ABEL & IMRAY,
Agents for the Applicant.