Improvements in Coiled Tubular Boilers and Apparatus connected therewith.
Year: 1890

page_text: Date of Application, 14th Aug., 1890
Complete Specification Left. 9th May, 1891-Accepted, 13th June, 1891
PROVISIONAL SPECIFICATION.
Improvements in Coiled Tubular Boilers and Apparatus connected
therewith.
1, FREDERICK TUDSBURY of Edwinstowe, in the County of Nottingham,
Woodcarver, do hereby declare the nature of my invention to be as follows:-
This invention relates in the first place to the construction of a coil boiler by
arranging and combining the tubes in such a manner as to expose the largest
amount of heating surface to the action of the fire, while occupying the minimum
of room; and in the second place to a method of and means for causing a
circulation of hot water through the coils, this action being accomplished by a
specially constructed pump working in combination with the usual feed water
pump.
In carrying out the first part of my invention, I bend the tubing which is
screwed or welded together so as to form one continuous length of internal and
external coils, enclosed in a suitable casing, in conjunction and having communi-
cation with a separator or steam vessel from which steam is taken for use, and
which is fitted with a safety valve and steam gauge, and internally with a ball
float.
The lower part of the coiled tubing is arranged as a fire box with an opening
for firing, and the bottom of which forms the grate being coiled in the form of a
flat volute with sufficient space between the coils.
Above the fire box the tubing may be coiled into a number of continuous
concentric coils, and a central coil of smaller sized tubing having its lower end
joined with the grate coil by means of a length of uncoiled pipe, may commence
above the fire box and be carried up the flue or chimney to a suitable height.
In a convenient position outside the coil casing I fix a closed vessel which I call
the "separator," from which I draw the required steam, it being connected with
the coil.
It contains in its lower part a ball float attached to a lever and spindle passing
to the outside through a stuffing box, and working an inlet and outlet valve
hereafter mentioned, and from below the said ball float, being the hot water space,
I take a pipe to the force pump which is hereafter described.
From the upper part or steam space of the separator I take the steam pipes,
and I also fix the blow off safety valve.
The combined force pumps which form the second part of my invention are
worked by the pressure of steam in the vessel I call the separator, and consist of
two pumps, namely a force pump of ordinary construction to supply the feed
water, and a combined steam motor and hot water circulating pump, hereinafter
called the motor pump.
These two pumps are placed in line, and have one
continuous piston rod, common to both, but varying in its diameter; in the feed-
water pump it is the usual plain plunger, and in the motor pump it is of larger
diameter and is provided with a piston of any suitable construction.
The motor pump consists of a cylinder provided at one end with a steam chest
and slide valve, receiving steam from the separator and a hot water double valve
box at the other end connected with the water space of the separator, and also
with the upper part or flue portion of the steam coil, and thus on one side of the
piston there is steam, and on the other side hot water under the pressure of
steam.
+
The rod of the slide valve is extended in bearings past the end of the motor
pump and, is provided with depending strikers or tappits which are struck and

page_text: moved by the projecting piston rod at each end of its travel, thus opening and
closing the steam and exhaust ports.
The action of the boiler is as follows:
The fire being lighted a few strokes of the pump made by hand, supplies water
to raise steam for working the pumps. The pump supplies more water than is
required for evaporation, and the surplus passes through the coils into the
separator until the working level is reached when the valve opens and allows the
feed water to escape through an overflow pipe.
This working level is maintained by the action of the float, which permits the
entrance or escape of water automatically as required.
The circulation of water through the coils is produced by the action of the
motor pump taking water from the hot water space of the separator and forcing it
into the coil at an elevated point from whence it circulates back to the separator.
The action of the motor pump is as follows:
The annular space in the cylinder being filled with hot water from the separator,
under steam pressure, and steam being admitted from the separator through the
slide valve to the opposite side of the piston which has a larger area on the steam
side owing to the difference in diameter of the piston rod, the piston is moved
forward and the hot water forced through the valve box into the coil; the end of
the piston rod now comes in contact with a tappit on the valve rod closing the
valve or steam port and opening the exhaust, on which the hot water under pressure
forces the piston back to the opposite end, or first described position, strikes the
second tappit on the valve rod thus opening the steam port and again reversing
the motion.
Dated the 11th day of August 1890
ROBT. F. DRURY, Fel. Inst. P.A.,
Bank Buildings, George Street, Sheffield, Agent for Applicant.
COMPLETE SPECIFICATION.
Improvements in Coiled Tubular Boilers and Apparatus connected
therewith.
I, FREDERICK TUDSBURY of Edwinstowe, in the County of Nottingham
Woodcarver 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 relates in the first place to the conformation and combination of
coils of tubes of iron or other metal, in such a manner as to expose the greatest
amount of heating surface possible to the action of the fire, in the smallest
possible space; secondly, to forcing water through the coils by mechanical means,
in addition to and independent of the feed water, into a steam holder or separator,
from which steam at high pressure may be taken and the water not converted into
steam is again pumped into the coils, as hereafter more particularly described; and
thirdly, to a specially constructed circulating and feed pump.
The invention is illustrated in the annexed sheets of drawings, in which
Fig. 1. is a partly sectional elevation of the complete apparatus.
Fig. 2. is an enlarged view of the pumps with part of cylinder removed to show
its internal construction.
The boiler or generator consists of coils of metal tubing either screwed or
welded together so as to form one continuous coil; a steam holder or separator
fitted with steam and water gauges, safety valve and the like; a feed pump and
circulating pump; and an outer covering of sheet-iron, brickwork, or other
suitable material.
The series of steam generating coils seen in Fig. 1, consist of a centre coil A,
which I prefer to make of smaller diameter tubing than the rest of the coils, and
I join the bottom end to the lower end of the firebox-coil B, the upper end of

page_text: which is joined to the bottom end of the second coil C, of the concentric series of
coils, which is again joined to the top of the outer coil D.
The upper part of the firebox-coil B, is coiled in the manner shown, so as to
leave an opening for firing purposes, and although I have represented in Fig. 1, a
generator having only three concentric coils in the upper part of casing, it will be
evident, and I wish it to be clearly understood that for larger generators, the
number of concentric coils may be increased to any desired number.
The end of the outer coil D, is screwed into a steam holder or separator L,
which may be of cast or wrought iron or steel, and fixed in any convenient
position; this holder carries the water and steam gauges, and safety valve; to
prevent complication these are not shown in the drawings.
The pumps, Fig. 2, which are worked in one direction by the pressure of steam,
and in the other direction by hot water, both steam and water being taken from
the holder or separator L; consist of two parts, first, a force pump of ordinary
construction to supply the feed water, and secondly, a steam motor and hot water
circulating pump in combination the two pumps are placed in line one with the
other, a piston rod of two different diameters being common to both, and carrying
the piston.
Referring to Fig. 2, the feed pump is marked a, and the steam motor />, and hot
water circulating pump cylinder; c, the piston; d, piston rod on the hot water
side of piston c, and made of large diameter to reduce the area of piston; d', piston
rod on steam side of piston, and which also forms the ram of feed pump a; e, is a
single action slide valve steam chest, is the valve spindle; G, the steam stop
valve; h, and ', arms or tappets for operating the slide valve, h, being moved by
means of a pin, or collar, or the like, k, attached to the piston rod d, on its
outward stroke, and by h', during the inward stroke.
17'
The valve box j, is provided with a hole i, to receive the hot water pipe I, seen
in Fig. 1, connecting the valve box, with lower part of steam holder L, m, is
a spring for actuating the steam slide valve motion, and n, is a hole to receive
exhaust steam pipe.
The action of the pumps is as follows; starting with the piston c, in the position
shown in the drawing, and the annular space between the walls of the cylinder b,
and piston rod d, being filled through the valve box j, with hot water, under
pressure from the steam holder I, by means of the pipe I, steam under pressure is
admitted by means of the valve G, through steam chest and valve port, to the
end of cylinder marked b, forcing forward the piston c, to the other end of the
cylinder, and expelling the hot water before mentioned as filling the annular
space, through the other valve box and through the pipe P, Fig. 1, into the
steam coil.
The steam side of piston c, being of larger area than the annular hot water
space on the other side, enables the steam pressure (which is practically the same
per square inch as that of the hot water in pipe 1) to overcome the resistance of
the hot water.
The piston having arrived at the end of the stroke, the steam in the cylinder is
exhausted through the pipe at n, by the movement of the slide valve, caused by
action of the tappet h.
The steam pressure being now removed, the piston is driven back by the pressure
of the hot water in the annular space, to the other end of the cylinder, at the
same time forcing the water out of the feed pump a, (which was charged with
water during the outstroke of piston) through the pipe Q, into the steam coils; the
area of the annular space before mentioned, and that of the feed pump ram d²,
being so proportioned as to allow of this.
The piston having arrived at this position it will be evident that the above
described movements will be continuously repeated, and thus keep both the
circulating and the feed pumps in action.
In the drawings Fig. 1, only one circulating and one feed pump is shown, but
for large boilers or generators I may use two or more sets of such pumps as

page_text: herein before described, and I may fix them in any convenient position, other than
that shown.
The action of the boiler or steam generator is as follows:-A fire being
lighted, a few strokes of the pump made by the hand, will supply sufficient water
to raise steam pressure to work the pumps, steam being admitted through valve G,
a rapid circulation of water is thus maintained through the whole length of the
coils, by means of the hot water circulating pump taking water from the lower
end of the steam holder L, and forcing it through the pipe P, Fig. 1, into
boiler coils at O, thus increasing the efficiency of heating surface, and preventing
the overheating of any part of the coils; also preventing the too rapid variation of
steam pressure in the steam holder.
The quantity of circulating water being much more than is required for
evaporation into steam; the fire has to act upon and raise the temperature of the
whole body of water in the apparatus, before the steam pressure can rise.
The proper water level in the steam holder or separator L, is maintained by
means of the feed pump a, in Fig. 2, delivering its water by the pipe Q, Fig. 1,
into the upper part of the coil A, this part of the coil down to the entrance of
pipe O, acting as a feed water heater.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is or may be performed, or carried into
practice, I declare that what I claim is :-
1 In the construction of coiled tubular boilers or steam generators, the
construction of the firebox coil B, in combination with a number of concentric
coils D, and a central coil A, connected together 50 as to form a continuous pipe,
substantially as hereinbefore described and as shown in Fig. 1, of the drawings.
2-In connection with coiled tubular boilers or steam generators, the method of
mechanically forcing the circulation of water in the coils, other than, and
independent of the feed water, as hereinbefore described, and with reference to
Fig. 2, of the drawings.
3-In connection with coiled tubular boilers or steam generators, a compound
pump and motor, constructed substantially as herein before described and shown in
Fig. 2, of the drawings.
1001
ROBT. F. DRURY, Fel. Inst. P.A.
Bank Buildings, George Street, Sheffield, Agent for Applicant.