Improvements in Steam and Hot Water Boilers.
Year: 1896

page_text: Date of Application, 3rd Mar.. 1896-4ccepted, 16th May, 1896
COMPLETE SPECIFICATION.
Improvements in Steam and Hot Water Boilers.
I, JOSEPHUS PLENTY of 148 Randolph Avenue, Jersey City, New Jersey, in the
United States of America, 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 :-
This invention has reference to steam and hot water boilers especially adapted for
heating purposes, the object being to produce a portable boiler having a comparatively
large area of heating surface, with a construction and assemblage of parts which
shall be compact and economical to build.
The boiler is of the double tubular type, in which the water or steam is
confined in the space between the inner and the outer tubes, the heat and products
of combustion from the furnace passing around the outer tubes and through the
inner tubes. The invention consists of an arrangement of tubes and diaphragms
with respect to the fire chamber, whereby a compact structure is obtained, and the
heat is economically distributed. The invention also consists of the specific
construction of the tubes.
Referring to the drawing.
Fig. 1 is a vertical central section of the boiler.
and
Fig. 2 is a horizontal half section of the boiler, taken on line of Fig. 1.
Fig. 3 is a section taken on line y y of Fig. 1, with parts broken away
Figs. 4 and 5, show the tubes in detail.
It being the intention to construct a portable boiler, the enclosing walls will be of
sheet metal, but the invention claimed herein is not limited to an apparatus so
constructed. Referring to the drawing by letter, A represents the fire chamber,
a the grate bars, and a the fire door. The rear wall of the fire chamber is a metal
plate or diaphragm & rising to a point about one half the distance to the dome or top
of the structure.
; a
A short distance from the rear wall b', I locate a second vertical diaphragm
space is left beneath the lower edge of this, but it extends entirely to the top of the
structure. Across the front of the boiler, a short distance from the front wall 6³, I
locate another vertical diaphragm ; this rises from a point above the fire door to
a point within a short distance of the top plate of the structure: another
diaphragm is arranged horizontally from the upper edge of the diaphragm 6', to the
diaphragm . The space between the outer casing, and the three diaphragms b³, b, b
constitute draft passages to be hereinafter more particularly referred to. The upper
portion of diaphragm which separates the vertical draft passage from the horizontal
draft passage is provided with openings & shown in Fig. 3.
Two sets of tubes C and C' respectively are used; the former are about twice the
length of the latter, and occupy the upper part of the structure below diaphragm b.
Tubes c' occupy the lower part of the structure and extend from diaphragm b, to
diaphragm being supported by said diaphragms. Each tube is duplex, consisting
of an external tube c and an internal tube c. In the set C, the tubes establish
communication between the vertical draft passages at the rear and front of the
structure, and in the set C, the tubes c' establish communication between the fire
chamber and the vertical passage at the rear of the structure. The outer tubes c in
both instances are exposed externally to the heat from the fire chamber which first
rises vertically, then passes rearwardly over the top of the diaphragm b, thence
downwardly and under the lower edge of diaphragm &, thence upwardly through the

page_text: draft passage at the rear of the structure, thence forwardly through the tubes e¹ of
the set C, to the vertical passage in the front part of the structure, and thence out
through the chimney D. A portion of the heat from the rear vertical passage also
passes through the openings ', and passes thence forward over the horizontal
diaphragm to the chimney.
The tubes are arranged in horizontal rows; those of each row being connected
together at their ends by cross passages e; these passages connect together the
water or steam space of each double tube.
The cross passages at the rear connect at each extremity by means of elbows e¹,
with a vertical tube f, which rises to an upper corner of the structure and leads
thence to a large central steam or hot water drum F by means of a cross pipe f¹.
The cross passages at the forward end of the set of tubes C connect in a similar
manner with vertical pipes g, which also rise to the upper part of the structure, and
there connect with the drum F. The lower ends of vertical tubes connect
respectively with single horizontal tubes A which lead forward and flank each side of
the fire chamber in the lower corners thereof.
The lower ends of pipes 9 connect in similar manner with single horizontal tubes i
flanking the fire chamber at the upper corners thereof, but extending only to the
diaphragm b. The tubes or drums i and h are connected together by a series of
vertical tubes j all of which are subjected to the heat from the fire chamber. The
cross passages connecting the forward ends of the set of tubes C₁ lead into short
vertical pipes which connect at their lower ends respectively with the two pipes .
Cold water is admitted to the pipes h, through the plugs h¹ and hot water or steam is
taken from the boiler through either or all of the plugs m in the dram F.
A feature of this invention is the construction and assemblage of the duplex tubes.
The inner and outer tubes are connected together at their ends by heads or
couplings o. The coupling at one end has an opening o', which the outer tubes
screws into; opposite this opening and upon the same axis is another opening o'
which the end of the inner tube fits.
The coupling at the other end of the tubes has an opening o' fitting the
outer tube, and opposite it upon the same axis another opening somewhat
larger than the end of the inner tube. The parts are assembled by first screwing
the two couplings on to the ends of the outer tube. The inner tube is then passed
through opening until it reaches opening o, at the other end, when it is screwed
into place therein. This tube is then secured by means of an interiorly and
exteriorly threaded bushing or nut p¹. The outer thread of which fits opening o
and the inner thread the tube.
This nut p is provided with a shoulder p. between which and the coupling o
the tube sheet or diaphragm in the boiler may be clamped, as indicated in Figs. 1
and 2 of the drawing. The cross passages connecting the horizontal rows of tubes
together are formed by short lengths of pipe q; these are threaded at each end,
and screwed into openings g' in the sides of the coupling.
Having now particularly described and ascertained the nature of this said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. In a steam or hot water boiler, the combination of a fire chamber, two sets
of duplex tubes, one longer, than the other, three vertical parallel diaphragms, a draft
passage beyond each of the outer diaphragms and passages for the products of
combustion, leading from the fire chamber around the exterior of both sets of
tubes, and through the shorter set of tubes to the passage beyond one of the outer
diaphragms, then joining and leading together through the longer set of tubes:
substantially as described.
2. In a steam or hot water boiler, the combination of three vertical parallel
diaphragms, draft passages arranged beyond the outer diaphragms, two sets of tubes
one set extending between the outer diaphragms, and the other extending between
the intermediate diaphragm, and one of the outer diaphragms a fire chambe

page_text: between an outer and intermediate diaphragm the draft from which leads directly
around the longer set of tubes and through set of shorter ones, then joining and
leading through the longer set, substantially as described.
3. In a steam or hot water boiler, a duplex tube, one within the other, in
combination with couplings at each end, threaded internally and externally, and
engaging respectively with the coupling and the tube and a diaphragm or tube
sheet clamped between the nut and the coupling.
Dated this 3rd day of March 1896.
HERBERT HADDAN & Co.,
18 Buckingham Street, Strand, London, W.C., Agents to Applicant.