IMPROVED APPARATUS FOR GENERATING STEAM
Year: 1858

page_text: LETTERS PATENT to Martin Benson, late of Cincinnati, Ohio, United
States of America, but now of Craven Street, Strand, in the City of
Westminster, Mechanical Engineer, for the Invention of "IMPROVED
Sealed the 16th November 1858, and dated the 21st August 1858.
PROVISIONAL SPECIFICATION left by the said Martin Benson at the
Office of the Commissioners of Patents, with his Petition, on the
21st August 1858..
I, MARTIN BENSON, late of Cincinnati, Ohio, United States of America,
but now of Craven Street, Strand, in the City of Westminster, Mechanical
Engineer, do hereby declare the nature of the said Invention for "IMPROVED
APPARATUS FOR GENERATING STEAM," to be as follows:→
The chief object of this Invention is to generate steam with great rapidity,
and at the same time ensure perfect safety in the action of the boiler. For
this purpose
the centre or flue space of the boiler (which is surrounded by a
water jacket) is divided into compartments by vertical partitions, which are
removable, and in each of the compartments formed by these partitions a
system of serpentine pipes is fixed, their lower ends communicating with a
pump situate near the boiler, and their upper ends communicating with the
steam space in the upper part of the boiler. The flame and heated gases
from the fire-place play upon and around these pipes, which present an
extended heating surface. A circulation of water is kept up through these
pipes by means of a pump, which draws its supply of water from the jacket
of the boiler, and forcing it through the system of pipes causes its rapid

page_text: conversion into steam.
Any water that comes over with the steam falls into
the water space, while the steam accumulates in the upper part of the boiler.
A second pump is used for supplying water to the shell of the boiler in the
usual way. In order to admit of any one of the systems of serpentine pipes
being thrown out of use, in case of their being burnt out, cocks are provided
at both ends of each system, by which means the connection between the
ends of any one of the serpentine pipes and the pump and water space of the
boiler may be cut off with facility. For the purpose of equalizing the supply
of water to the several systems of pipes, the passages of the connecting
branch pipes are contracted sufficiently to afford a slight impediment to the
movement of the water as it is impelled forward by the circulating pump.
To render the action of the steam valve efficient it is weighted by means of a
lever connected by a pendent rod to a bell-crank lever, the upper arm of
which carries the weight. As the valvo rises under the accumulating pressure
of steam, the crank lever is rocked, and the weighted arm is caused to approach
nearer to a vertical line. This movement necessarily reduces the gravitating
force of the weight, and consequently a gradually decreasing resistance is
presented to the rise of the valve. When the improved boiler is required to
be set in action, the fuel in the fire chamber is ignited, and a few strokes are
given to the circulating pump by hand. Sufficient steam will then be quickly
generated to set the engine in action, and the further movement of both the
supply and circulating pumps may be left to the engine.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Martin Benson in the Great Seal Patent Office on the
21st February 1859.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, MARTIN
BENSON, late of Cincinnati, Ohio, United States of America, but now of
Craven Street, Strand, in the City of Westminster, Mechanical Engineer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-first day of August, in the year of our
Lord One thousand eight hundred and fifty-eight, in the twenty-second year
of Her reign, did, for Herself, Her heirs and successors, give and grant
unto me, the said Martin Benson, Her special license that I, the said
Martin Benson, my executors, administrators, and assigns, or such others
as I, the said Martin Benson, my executors, administrators, and assigns, should

page_text: 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 "IMPROVED
APPARATUS FOR GENERATING STEAM," being a communication from abroad, upon
the condition (amongst others) that I, the said Martin Benson, by an instru-
ment in writing under my hand and seal, 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 Martin Benson, do hereby declare
the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement, reference being had to the Drawings hereunto annexed, and to
the letters and figures marked thereon (that is to say) :-
:-
This Invention, as communicated to me by my foreign correspondent,
relates to a novel arrangement of apparatus by means of which steam may be
generated with great rapidity and economy, and that with perfect safety to the
attendants. This object it is proposed to effect by the use of a serpentine
arrangement of tube's suitably arranged in the jacket or shell (by preference)
of the vertical form of boiler. The centre or flue space of this boiler (which
in the first arrangement, hereafter described, is surrounded by a water jacket)
is divided into compartments by vertical partitions which are removeable, and
in each of the compartments formed by these partitions a system of serpentine
pipes is fixed, their lower ends communicating with a pump situate near the
boiler, and their upper ends communicating with the steam space of the boiler.
The flame and heated gases from the fire-place play upon and around these
pipes, which present an extended heating surface. A circulation of water is
kept up through these pipes by means of a pump, which draws its supply of
water from the jacket of the boiler or other water space in connection with the
system of serpentine pipes, and forcing it through these pipes causes its rapid
conversion into steam. Any water that comes over with the steam falls into
the water space, while the steam accumulates in the upper part thereof.
A second pump is used for supplying water to the jacket of the boiler in the
usual
way.
In Sheet I. of the accompanying Drawings, Fig. 1 is a sectional elevation
of one arrangement of the improved boiler, taken in the line A, A, of Fig. 3,
and shewing a transverse section of the serpentine tubing; Fig. 2 is a longi

page_text: tudinal section, taken in the line B, B, of Fig. 3; Fig. 3 is a plan view of the
greater part of the apparatus, shewing certain portions of it in section, for
more fully understanding its operation; Fig. 4 more fully represents the
means employed for weigliting the safety valve lever, to enable the valve to
open fully when steam is raised to the desired pressure, and allow of its
escape, thus preventing any undue increase in the pressure of steam in the
boiler; Figures 5 and 6 shew, in end view and section, what I denominate a
'choking plug:" Plugs of this construction I place in branch pipes, which
are employed to divide and conduct forward the stream of water that flows
from the circulating pump, and compel an equal quantity to pass into each
section of the tubes.
"
The boiler is composed of an inner and outer shell a; the space between
then serves as water and steam room, while the chamber which the water
space surrounds is occupied at the upper part by the system of serpentine
pipes, through which the water to. be generated into steam circulates, and at
the lower part this chamber constitutes the fire-place. The outer and inner
shells are stay-bolted in any suitable manner, and furnished with fire-door
openings similar to other boiler shells of a like structure; g represents the fire
bars of the furnace, and h is a cast-iron frame or plate on which the boiler
stands; or it can be constructed with the bottom furnished with a water
space, and made to rest on masonry, or the flooring of buildings or of vessels
when placed in them.
It will be seen that the ends of the tubing 1, 2, 3, 4, 5, up to 32, are not
attached to tube plates as in the ordinary inarine and locomotive tubular
boilers, for connecting them with the water space, but that the tubes of each
section are connected to each other respectively at their ends by semicircular
pieces 33; as fully represented in Fig. 2, whereby they form one continuous
tube or section of tubes. The water to be evaporated is forced into the
tube 1 at the lower part of the section up to the tube 32, which is attached
to and leads into the top of the boiler, as fully represented in Fig: 2, and the
semicircular pieces 33 are furnished with flanges to facilitate their attachment
to the plates c, c, at each end of the tubing. The sections of tubes thus
formed are set up in 'the inside shell of the boiler, and rest on pieces of angle
iron f, bolted to the opposite sides of the boiler, as represented, and the
sections of tubes are held. fast át top by means of bolts d (which pass through
the plates c, c,) to the inside shell of the boiler. In constructing the sections
of tubes the serpentine lines may be arranged one above the other in the same
plane, as indicated in Fig. 2, or in a zig-zag manner, as represented in Fig. 1.
The latter plan has, however, been found by experience to be the best, for

page_text: when the tubes are placed one directly above the other there are open spaces
left between every tube, through which the heat will rapidly escape in its
passage upwards without being absorbed, and thus à loss of heat will result.
which is not the case when they are placed as represented in section in
Fig. 1, for then the currents of heated gases are deflected, and caused to
circulate around the tubing.
I will now describe the means employed for keeping a constant and regular
supply of water to the systems of serpentine tubes, but first I must state how
the shell portion of the boiler is supplied. Connected with the water space
formed by the outer and inner case or shell of the boiler, by means of a pipe
W, is a closed metal box or water chamber 45, supplied with water through a
pipe 46 by any ordinary construction of feed pump actuated by the engine,
which receives its steam from the boiler.
A pipe s leads from this water chamber to the circulating pump r, which is
shewn as composed of an ordinary steam engine cylinder with a slide valve and
openings common to such construction of engines, the piston and valve of
which are operated, as is well understood, by an ordinary arrangement of
crank and excentric, but any other kind of pump may be used, if thought
desirable.
This circulating pump is connected by means of branch pipes (the arrange-
ment of which is shewn best in Fig. 3), with the serpentine systems of pipes
before mentioned, and as therefore the pump is set in action, it draws water
from the chamber 45, which entering the exhaust opening passes into the
cylinder with a suitable action of the valve, and is then forced up into the
chest and out into the branch pipes, by which the water is distributed to the
several systems of serpentine tubes.
Thus it will be understood, that the water supplied to the serpentine tubes
is indirectly drawn from the shell of the boiler, and a constant circulation is
consequently kept up throughout the boiler; the pipes could, if required, be
attached direct to the shell of the boiler, but it has been found best to draw
the water from a closed chamber, on which the fire has no direct action, as
the pump then supplies itself more regularly with water; for, the water in the
boiler shell being often in an agitated state produced by the heat, an irregular
supply of water to the pump will often ensue.
The circulating pump r being in constant work, a constant supply is kept
up without any risk of overfilling the boiler. The water is also kept in
constant circulation through the tubes, and it is thus caused to absorb heat with
much greater rapidity than if it were at rest.
The mechanical force imparted to the circulating water coupled with the

page_text: action of the steam also serves to prevent the lodgement of any sediment or
incrustating matter in the tubing.
For equalizing the supply of water to each section of tubing, the following
contrivance is provided:-The main stream as it proceeds from the pump r,
is first divided by the branch pipe b, and then subdivided by the branch
pipes x, x, making four streams for supplying the four sections of tubes. In
like manner the supply could be extended to eight or sixteen sections of
tubes, if desired, or each section of tubes could be attached to a main supply
pipe.
Now, in order to equalize the quantity of water supplied to each section of
tubing, in each of the branch pipes is inserted a choking plug," which con-
sists simply of a plug fitting the pipe, and furnished with a central division
plate at the opposite sides of which elbow passages are formed, leading off into
opposite directions. These plugs serve the double office of dividing and
throttling the supply of water as it enters the branch pipes, and thus an
increased pressure of two or thre pounds is required on the circulating pump,
above that in the tubing, for the purpose of forcing the water supply into the
several sections of the tubing, the pressure in which often varies, owing to the
inequality of heat in the several parts of the furnace.
For the purpose of ensuring safety to the attendants of steam generators,
it is now proposed to provide a means of weighting safety valves that will
present less resistance to the pressure of the steam in proportion to the distance
the valve has risen from its seat, and thus remove the defect common to the
ordinary valve, whether furnished with a lever and weight or a spring for
retaining it on its seat.
At Figures 2 and 4, & is the safety valve mounted on the steam chamber j,
and held down to its seat by a weighted lever n. Pendent from the end of
the weighted lever is a rod m, which is connected to the lower arm P of a bell
crank lever, having for its fulcrum the stud pin q affixed to the boiler shell.
From the end of the upper arm o of this bell crank, is pendent a weight 41
for holding the valve down on its seat. (If desired, a spring of any kind may
be used in place of the weight.)
Now it will be readily seen, that as soon as the valve lever commences to
rise, the arm o, to which the weight is attached, will approach a vertical
position, and thus its power over the valve lever will proportionately decrease,
while the arm p, to which the valve lever is connected, will approach a
horizontal position, and thus relieve the valve from the weight to such a
degree that the valve will be thrown wide open at any pressure of steam
sufficient to start the valve from its seat.

page_text: Thus it will be understood, that when a safety valve is weighted according
to this improvement, it will be impossible for a greater pressure of steani to
accumulate in the boiler than it is calculated to carry.
In the working of the improved boiler, should anything happen to either
section of the tubing to make repairs necessary, the supply of water can be
shut off, and also the connection between the upper part of the tubing and the
steam space by means of cocks 36 and 37 (represented with dotted lines in
Figures 2 and 3), which are situate at the extremities of the several sections
of serpentine pipes. This provision admits of any one section of the tubing
being taken out when injured, and of the rest of the boiler or tubing being
used until it is found convenient to commence the repairs. 84 is a pipe
furnished with a stop-cock 35, and connecting the water space of the boiler
shell with the supply pipe 6, leading to the serpentine tubes, for the purpose of
letting the water out of the boiler shell into the tubing, in case of the circu-
lating pump r getting out of repair and ceasing to operate while a strong fire
is in the furnace, and thus preventing the tubing from being injured by the
heat.
In place of constructing the boiler with a jacket for receiving and con-
taining water and steam, as before described, the tubing can be set in brick-
work, as represented in Sheet II. of the accompanying Drawings, a receiver
being placed at one side thereof for receiving the steam and water from the
tubing by means of a suitable arrangement of pipes.
.
Fig. 1 is an elevation of the boiler shewing part of the tubes in transverse
section; Fig. 2 is a sectional elevation, showing the longitudinal direction of
the tubing; and Fig. 3 is a transverse section of the boiler case, showing the
manner of joining the bricks together. a, a, represents an iron casing
surrounding the brickwork; b, b, and c, c, is the steam receiver furnished with
a safety valve pipe d.
Each section of tubing h; h, is supplied with water through the pipes i, i,
(which are furnished with chokers) by means of a circulating pump, which pump
will draw the water from the lower part of the steam receiver c through the
pipes k; m is the pipe through which the water is supplied to the receiver c;
and 9, 9, 9, are pipes for connecting the tubing with the steam pipe f, which
pipe f conducts the steam and water to the receiver c. The receiver c should be
clothed with some good non-conducting substance to prevent the loss of beat
by radiation. By this arrangement the water jacket of the boiler is dispensed
with, which renders the boiler cheaper to construct and much less liable to
give way, and, cleaning can be readily effected, as all sediment and dirt will

page_text: deposit in the receiver, which can be made large enough to admit of the
entrance of a person to clean it.
1
. The boiler thus constructed is more particularly intended for steam vessels.
For greater security, it is preferred to make the bricks lock into each other,
and the brickwork may be secured to the iron casing with bolts inserted at
suitable intervals to sustain the fabric. When, however, this construction of
boiler is intended for stationary purposes, the iron casing will not be required.
The circulating of the water by means of a suitable pump, the means for
choking the tubes and of shutting off any one section of the tubes, and also
the improved safety valve, will be employed as well in this arrangement of
boiler as in the boiler constructed after the plan first described.
Having now explained the nature of the Invention of "Improved Apparatus
for Generating Steam," as communicated to me by my foreign correspondent,
and explained the manner of carrying the same into effect, I do not claim as
of the Invention secured to me under the above in part recited Letters Patent,
the use of serpentine pipes for heating water supplied thereto by a force pump
for the generation of steam; but what I claim is,―
First, causing a constant circulation of water through the series of serpentine
tubes supplied from the shell of the boiler, or from a closed water chamber in
connection therewith, as described, whereby a rapid generation of steam and
its disengagement from the heated water is effected.
Secondly, the means whereby the supply is equalized between the several
series of tubes..
Thirdly, the means described for providing for the cutting off of any one of
the series of tubes without affecting the action of the others, and also for the
removal of any one of the series without the displacement of the others.
Fourthly, weighting the safety valves of steam boilers, so that the resistance
offered by the weight or pressing spring to the rise of the valve will decrease
in proportion to the rise of the valve from its seat.
In witness whereof, I, the said Martin Benson, have hereunto set my hand
and seal, the Seventeenth day of February, in the year of our Lord
One thousand eight hundred and fifty-nine.
MARTIN BENSON. (L.S.)