Improvements in Sectional Water Tube Boilers.
Year: 1895

page_text: Date of Application, 23rd July, 1895-Accepted, 12th Oct., 1895
COMPLETE SPECIFICATION.
Improvements in Sectional Water Tube Boilers.
I, FRANK THEODORE MARSHALL, of No. 16 Eskdale Terrace, in the City
and County of Newcastle-on-Tyne, Mechanical 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 :-
The object of my invention is to construct a sectional water tube boiler having
the following advantages, viz. :-
1st. Obtaining perfect freedom for expansion of the various parts of the boiler
relatively to each other.
2nd. The facility with which any section of the boiler, if injured, can be
removed, leaving the rest of the boiler in a workable condition.
3rd. The accessibility for cleaning and repairing the internal and external parts
of the boiler afforded by the arrangement.
On the accompanying drawings 1 illustrate my invention as I propose to
generally carry it into practical application.
On Sheet 1, Figure 1 shows a half end elevation looking on back of boiler with
casing removed.
Figure 2 shows a half end elevation looking on front of boiler with casing
removed.
Figure shows a side elevation of boiler with casing removed.
On Sheet 2 are shown to a larger scale, details of the various parts of the
boilers.
Figures 4 and 4 show respectively sections of portions of an upper header and
a lower header with their respective connections to the dome and feed supply
pipe.
Figures 5 and 54 show sections of the same with the tube plate of the header
suitably shaped for the fitting of straight tubes.
Figure 6 shows a method of fitting the tubes to the tube plates wherein the end
of the tube is contracted.
Figures 7, 8, 9, and 10 show sections, end elevation, and plan of the junction
boxes showing methods of connecting the tube ends to the same.
Referring to the drawings, it will be seen that the boiler consists of-
A steam dome A, a number of sections of heating tubes each section consisting
of an upper header B, and a lower header C, placed side by side and connected by
a number of pairs of tubes T1 and T2, the back ends of each pair of which are
connected by a junction box D, that is, the tubes T¹ are suitably connected to the
header C at one end and to the junction box D at the other end, whereas the
tubes T2 are suitably connected to the junction box D at one end and to the header B
at the other end.
The upper headers B are all connected to the steam dome A at their upper end,
by means of the joints F.
The lower headers C are at their lower ends connected, preferably for economy
of space, by an expanded pipe G or by other suitable means to a feed supply
pipe E, which is connected at one or both of its ends with the steam dome A, by
means of pipes P at the lower end of which are placed mud boxes H.
The boiler is arranged inside of a suitable casing, the firebars being arranged
underneath the boiler proper as described above, and the furnace gases being
directed by suitable baffles, so as to be kept in contact with the heating surfaces of
the boiler as long as possible.
When the boiler is at work, the feed water is either supplied to the dome A

page_text: passing thence down the pipes P, or to the upper part of mudbox H by the
branch J, and thence in either case passes into the feed supply pipe E.
From the pipe. E it will pass through the pipes G into the lower or rising
header C from which it will circulate through the various pairs of tubes T1 and T2
into the upper header B, and thence, as steam or steam and water, into the dome A,
which is fitted with suitable steam drying baffles K.
Any water carried over with the steam may return by the downcast pipes P to
the mud boxes H which can be cleansed by blowing through the branch L.
"
Referring to Sheet 2 of the drawings Figs. 4 and 4* are sections of portions of
the upper "header" B and the lower "header" C shewing the method of joining
the tubes T and T2 by bending their ends to suit the vertical tube plates of the
"headers one of the access doors M being shewn in positión fixed by the internal
cross bar N being screwed up by the nut O on its screwed spindle against the face
of the door. The flange joint connects the upper "header" B to the dome, and
the expanded pipe G connects the lower "header" C to the feed pipe E.
When any section, comprising "headers," junction hoxes and tubes, is required
to be taken out, the flange joint F is broken and the expanded pipe G is cut
through and blank flanges applied to close the connection between that section and
the dome and feed pipe respectively.
"
Figs. 5 and 5 shew sections of the upper and lower "header" with the tube
plates so angled or "joggled ' as to suit the connection with straight tubes T¹
and T2, the access doors being removed. Fig. 6 shews the tube T2 joining the
vertical tube plate of the "header" B by being contracted so as to be inserted
in a smaller hole, the same method applying to the lower "header "C with the
object of causing a more rapid motion of the water from the "headers" into the
tubes and from the tubes into the "headers" and also enabling the space between
the tubes to be reduced thus using a narrower "header" with this form of
tube end.
Figs. 7, 8, 9 and 10 show respectively sections, end view, and plan of the
junction boxes D. Figs. 7 and 10 shew two different methods of jointing the ends
of the tubes to the junction boxes either of which may be suitably adopted.
By the method shown on Fig. 7 slight grooves are cut in the mouth of the
junction box D, the tubes T1 and T2 being expanded so as to fit into these
grooves.
Fig. 10 shows another method of joining the junction box D with the tubes T¹
and T. In this method a collar a, is screwed upon the tube, the joint being then
screwed up tight by means of the nut 6 which screws upon a thread cut upon
the mouth of the junction box D, and so draws up the tube by means of the
collar d.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is-
1. The construction of a water tube boiler in sections, consisting of double sets
of tubes as described, each vertical set having an independent header at the front
end, and each pair of tubes being connected by a junction box at the back end,
thus ensuring freedom of expansion of the different sets of tubes relatively to each
other substantially as described and shown.
2. The arrangement of the boiler whereby any section, comprising tubes,
headers, and junction boxes, may, if injured, be readily taken out, by the breaking
and blanking up of the joints F and G, still leaving the rest of the boiler in a
workable condition substantially as described and shown.
Dated thie 22nd day of July 1805
T. J. DANSON, F. Inst. P.A.,
Agent for Applicant.