IMPROVEMENTS IN GENERATING AND APPLYING STEAM AS A MOTIVE POWER, AND IN APPARATUS EMPLOYED FOR THESE PURPOSES
Year: 1860

page_text: LETTERS PATENT to Maurice Sautter, of No. 14, Boulevart Montmartre,
in the City of Paris, Banker, for the Invention of "IMPROVEMENTS IN
GENERATING AND APPLYING STEAM AS A MOTIVE POWER, AND IN APPARATUS
EMPLOYED FOR THESE PURPOSES."-A Communication from Mr. Joseph Gill,
1
1
Sealed the 12th March 1861, and dated the 19th September 1860.
PROVISIONAL SPECIFICATION left by the said Maurice Sautter at the
Office of the Commissioners of Patents, with his Petition, on the
19th September 1860.
I, MAURICE SAUTTER, of No. 14, Boulevart Montmartre, in the City of
Paris, Banker,do hereby declare the nature of the Invention for "IMPROVEMENTS
IN GENERATING AND APPLYING STEAM AS A MOTIVE POWER, AND IN APPARATUS
EMPLOYED FOR THESE PURPOSES," to be as follows:-
This Invention has for its object improvements in generating and applying
steam as a motive power, and in apparatus employed for these purposes. In
generating steam, according to this Invention, a boiler having two compart-
ments is employed; one compartment is kept entirely full of water, and in this
compartiment the water is heated. No vapour is allowed to form in this com-
partment, but a portion of the water contained in it is from time to time
injectedintothe second compartment, which constitutes a vapourizingchamber.
The pressure in this compartment is always less than what is due to the
temperature of the injected water,consequently part of this water is instantly
converted into steam, whilst the temperature of the rest of the water falls to
[Price 8d3

page_text: the point corresponding to the pressure in the vapourizing chamber. In the
upper part of the vapourizing chamber a mass of pebbles or other substanceis
placed, so as to catch and hold back the fine particles of water generally
existing more or less in the vapour in a state of suspension. The water which
accumulates at the bottom of the vapourizing chamber is by means of a pump
injected into the heating compartment of the boiler, and the apparatus is so
arranged that as the piston of the pump forces a quantity of water into the
heating compartment of the boiler a quantity of water from the heating com-
partment is ejected into the barrel of the pump at the back of the piston. On
the return stroke of the piston the communication between the heating com-
partment and the pump is closed, and a communication is opened to allow the
heated water in the pump barrel to escape into the vapourizing chamber,
when a portion of it, as before explained, is converted into steam. The heated
water is, by preference, allowed to escape into the vapourizing chamber just
at the commencement of each stroke of the engine. The level of the water
in the vapourizing chamber is kept at a constant level; the water converted
into steam being replaced by fresh water forced in by a pump or otherwise.
The upper part of the vapourizing chamber is furnished with a safety valve,
and a pipe leading from the heating compartment to the vapourizing chamber
is also furnished with a safety valve,so that if the pressure in the heating com-
partment becomes too great a portion of the water will escape into the
vapourizing chamber and be partly converted into steam. When employing
steam expansively in engines known as Woolf's engines, in place of allowing
the steam from the small high-pressure cylinder to escape direct into the
expanding cylinder, I allow the steam to escape into a reservoir or apparatus,
where it is highly heated before it passes to the larger cylinder. In addition
to the advantage derived from heating the steam in its passage from one
cylinder to another, the reservoir or heating apparatus retains a constant
supply of steam for the larger cylinder, and the pistons of the two cylinders
are not therefore obliged to move simultaneously, as in common Woolf
engines, but they may be placed at an angle to each other.
Saturated steamand superheated steam are sometimesmixed before admis-
sion to the cylinder, but it should be observed that when both fluids are of
equal pressures, the superheated steam by parting with its heat to dry the
steam mist contracts more in the process than the other expands. If, how-
ever, the superheated steam be of considerably higher pressure than the moist
steam, and if the latter be in the act of tumultuous expansion when the
mixture is made, a good result is obtained as the mixed steam remains dry,
and even more or less superheated. I obtain this effect in a single cylinder

page_text: engine by generating the steam in the boiler at a pressure considerably above
the working pressure and wiredrawing it into a steam space, into which the
superheated steam (at the pressure of the boiler) is injected; thus the
pressure in the steam pipe near the boiler being regularly higher than that in
the steam space at the other extremity, gives a point d'appui to the pressure
of the mixed steam. Or, in cases when the steam expands tumultuously in
the cylinder itself,as in the Cornish engine, with contracted steam ports, an
injection of steam gas is made directly into the cylinder, the general principle
being to mix the superheated steam with the moist steam in the act of
tumultuous expansion; I apply this principle in the double cylinder system by
injecting the high pressure steam gas into the reservoir between the cylinders
above described, with or without other application of heat to this vessel.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Maurice Sautter in the Great Seal Patent Office on the
18th March 1861.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, MAURICE
SAUTTER, of No. 14, Boulevart Montmartre, in the City of Paris, Banker, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Nineteenth day of September, in the year of our
Lord One thousand eight hundred and sixty, in the twenty-fourth year of
Her reign, did, for Herself, Her'heirs and successors, give and grant unto
me, the said Maurice Sautter, Her special licence that I, the said Maurice
Sautter, my executors, administrators and assigus, or such others as I, the
said Maurice Sautter, my executors, administrators, and assigns, should 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 "IMPROVE-
MENTS IN GENERATING AND APPLYING STEAM AS A MOTIVE POWER, AND IN APPA-
RATUS EMPLOYED FOR THESE PURPOSES," a communication to me by Mr.Joseph
Gill, Gentleman, resident at Marsala, Sicily, upon the condition (amoligst
others) that I, the said Maurice Sautter, my executors or administrators,
by an instrument in writing under my, or their, or one of their hands
and seals, should particularly describe and ascertain the nature of the said
Invention, and in what manner the same was to be performed, and cause the

page_text: 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 Maurice Sautter, 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 bythe following
statement thereof, that is to say:-
In physical science generally our experience or knowledge of facts is far
in advance of our correct theoretical knowledge, and this remark is particularly
applicable to steam engineering,as in the generation of steam some important
phenomena in the action of the boiler are commonly explained upon obviously
erroneous principles; and in the practical application of the steam in the
engine we find in the best specimens of construction some essential points in
direct opposition to the thermodynamical theories taught by our highest
authorities. Thus, as regards boilers, the formation of scale or compact
crystalline incrustation is generally attributed to the deposit of earthyparticles
thrown out of chemical solution in the mass of boiling liquid and floated about
in mechanical suspension until they subside to the bottom, and there become
fixed and indurated as scale," a view of the case which I shall presently show
to be erroneous. And as regards engines we find that in the best examples
of the working of the Cornish engine given by Wicksteed, a very large propor-
tion of the expansion is effected by wiredrawing the steam, whereas by our
theory the same amount of expansion by the direct cut off of the steam should
give much more power, and again expansion in a single cylinder should
theoretically produce better effect than in a Woolf engine where the steam
passages between the small and the large cylinder are of considerable capacity,
yet ample experience has proved that within certain limits no loss of useful
effect ensues from the free tumultuous expansion of the exhaust steam from
the small cylinder into the comparatively vacuous space of the passage between
the cylinders.
As my improvements are based upon physical views, which I believe to be
novel,a brief sketch of my theory will help to explain the nature of my said
improvements.
And, first, as to the formation of scale in boilers, an evil of immense mag-
nitude, particularly in marine engines, always increasing with increase of
pressure I submit that in the molecular phenomena of the conversion of water
into steain many of the solid particles are thrown out of solution at exceedingly
minute distances from the inuer surfaces of the boiler with which the liquidis
in contact; and when these distances are within the sphere of the attraction
of cohesion with these surfaces, the particles are at once arrested by this

page_text: active force, and instantaneously fixed in such positions as the laws of crystalli-
zation or atomic aggregation of the substance enforce, and so become portion
of the molecular structure of the forming scale. When the solid particles
thrown out of solution are in the act of chemical separation from the liquid
beyond the sphere of the attraction of cohesion with the heat-transmitting
surfaces they remain free in a state of mechanical suspension in the water and
may be got rid of without forming indurated deposit or incrustation. In
proportion as the pressure in the boiler is high, the nascent globules of vapor
are smaller, and consequently the mineral particles in the act of being thrown
out of solution are at proportionately shorter molecular distances from the
heat-transmitting surfaces and from each other. Under these circumstances
a greater number of solid particles must come within the sphere of attraction
of cohesion in a given space for equal amounts of vaporization, and hence
the more rapid and copious formnation of scale in high-pressure boilers.
Secondly, as regards the apparently anomalous facts of the practical
advantage of wire drawing the steam, and the absence of loss from its tumultuous
expansion in the passages between the cylinders of a Woolf engine, I would
direct attention to a celebrated experiment made by Joule, of Manchester,
many years ago in his interesting researches on the dynamical nature of heat.
In this experiment compressed air was expanded to an equal extent by two
methods, first, by moderated expansion from which available mechanical work
was necessarily obtained; and secondly by free tumultuous expansion into a
vacuous space from which no mechanical work was obtained. In the first
case it was observed that the temperature of the apparatus fell, and it was
deduced that heat had disappeared, being converted into the work perforined;
whereas in the second case the temperature of the apparatus remainedconstant,
and it was deduced that no heat disappeared, because no mechanical work was
developed. The facts of these experiments are correct, but the deductions are
fallacious, and I submit the following as the true interpretation of the
phenomena. In the first case the quiet expansion of the air naturally causes
a fall of temperature in the dilated mass, or a change of sensible heat into
latent, the total quantity of thermometric heat in the apparatus remaining
precisely the same, only altered in quality or condition. In the second case
the tumultuous expansion actuallyincreases the original amount of heat in the
apparatus by a quantity equal to the apparent loss in the former case.
It is an admitted fact that the heat of saturated steam is (very nearly) a
constant quantity, while every practical engineer knows that the amount of
work-producing energy in steam is in proportion to its temperature, and that
in expansive working there is merely a change in the condition of the heat

page_text: from sensible to latent without any theoretical loss or disappearance from con-
version of thermometric heat into mechanical work. The conversion is
obviously that of energy into mechanical work by the transfer of the energy
from one portion of matter to another, heat in its different conditions in these
phenomena being the sign or manifestation of the molecular state or condition
of the matter concerned. Thus, in elastic fluids, sensible heat is the sign or
invariably accompanying circumstance of statical energy, or the elemental
spring wound up, while latent heat is the sign or accompanying circumstance
of energy in action, or the spring unwinding. Energy is held to be indestruc-
tible by any natural means; and as in the second case of Joule's experiment
above mentioned, the energy remained in the expanded air when not transferred
to anything else, and showed itself by the heat developed, so in the wire*
drawing and in the tumultuous expansion of steam, (which are almost identical
processes) energy does not disappear, but manifests itself in a more diluted
condition by drying the steam more or less if saturated and superheating it if
already dry. This view of the subject in connection with the well-known
loss of useful effect from internal evaporation in the cylinders of steam
engines helps to explain the apparent anomalies exhibited by the practical
results of wiredrawing and tumultuous expansion of steam.
Having thus briefly premised the principal novel points of my theoretical
views, I will now proceed to describe the practical improvements I have
effected by their application.
And first, as to the generation of the steam.-I construct the heating part of
my vaporizer or improved boiler of tubes,sheet spaces, or cells, entirely full of
water, maintained under a pressure greater than that of the working steam,
and heated above its temperature. No vapour is allowed to form in these
water-spaces under ordinary circumstances, but by means to be described
presently a portion of this superheated water is displaced at intervals, and
injected into another compartment of the boiler, which constitutes a vaporizing
chamber, and at the same time a steam space; and as the pressure of the
steam therein is regularly lower than what is due to the temperature of the
injected water, it is evident that part of this water will, under the relieved
pressure, instantaneously become steam by the self-contained heat of the mass,
while the temperature of the remainder falls to the point corresponding to the
pressure in the steam space. I make this space as small as is compatible with
the formation of dry steam, and this object is efficiently promoted by placing
in the upper part of it a mass of flint pebbles or similar fragments of some
steam-resisting substance, which occupies much of the space, but still leaves
The large
ample passage for the steam through the interstices of the mass.

page_text: interior surface thus exposed to the passing steam tends to catch and hold back
the fine particles of water generally existing more or less in the vapor in a
state of mechanical suspension. At each injection of the superheated water,
made preferably at the beginning of each stroke of the engine, a sudden
increase of pressure occurs in the steam, gradually declining to the end of the
stroke, and so far the steam acts expansively. Moreover, the sudden develop-
mentor flashing of steam from the superheated wateris analagoustotumultuous
expansion, and as the energy corresponding to the excess of the initial
temperature above the medium temperature of the working steam is not
transferred to anything else in the process, it tends more or less to dry the
steam; but the principal object in view in this method of vaporization is the
prevention of scale properly so called, which, according to my theory, above
explained, cannot form in this process, where all the earthy particles thrown
out of chemical solution remain free in the liquid in a state of mechanical
suspension, and settle down as mud or sediment in the still water at the bottom
of the vaporizing chamber, the mechanical circulation of the water being
sufficienttopreventincrustation from deposit on the heat-transmitting surfaces.
The following description in connexion with the Diagram,inarked Figurel
in the annexed Drawing,shews how these principles are practically embodied.
The water-space or heater is here, for more simple illustration, shewn as a
single coil of pipe a. preferably of rather small diameter to combine strength
with a sufficient heating surface in a compact form, and with a small mass of
water. It is kept quite full of water, and receives the action of the fire on all
sides, being enclosed in a casing of brick work, or a double water envelope,kept
also quite full, and forming in fact part of the water-space of the boiler.
Exterior to the foregoing arrangement is the vaporizing vessel b, the lower
part of which contains water, and the upper part steam, when the apparatus is
in action. Within this vessel, or exterior to and connected with it, is a pump c,
the plunger of which d is actuated by hand or by independent mechanical
power while the engine is at rest, or by the engine itself when in motion. The
three-way cock e, or an equivalent slide is so connected with the pump gearas
to keep open the passage fbetween the barrel cand the steam chamber during
the up stroke of the plunger, while the passage g between the pump and the
heater a is closed, and vice versa, to keep open the passage g during the down
stroke while the passage is closed. The valves h, i, are self-acting, or they
may be advantageously substituted by a slide worked by the pump gear. A
safety valve k allows an escape of water or of steam into the chamber b, in case
of excessive pressure from over heating inthecoil a; but, as already explained,
no steam should form therein under ordinary circumstances. The feed water

page_text: is sent in through the tube 7, and the sediment is occasionally blown off through
the pipe m. In some cases I apply a coarse filter between the valve i and the
mass of water in the vessel b, but this is not essential.
The action is as follows:-The vessel b being partly full of water as shewn,
and the water-spaces of the heater being quite full, the fire is lighted, and at
the same time, or preferably immediately before, the plunger is set in motion.
During the upstroke, the passage of being open and g shut, water flows into the
barrel through the valve i; and during the down stroke it is sent through the
valve h, into the lower part of the heater coil a, displacing an equal quantity
from its upper extremity through the passage g into the top of the barrel;
and this operation absorbs no power except in overcoming friction, as it is a
simple action of circulation of the water. On the succeeding ascent of the
plunger d,the passage g being closed, and open, the water will be discharged
into the steam space of the chamber b, while a fresh supply is taken into the
pump from below, to be in its turn sent into the heater on the down stroke of
the plunger. As the contents of the heater become hot, vapour will forin from
the water discharged through f, and at 212°Fahrenheit and upwards, regular
steam is developed. Suppose the steam pipe n to be open to the atmosphere,
the stroke of the plunger d to displace one cubic foot of water, and the tem-
perature of the superheated water to be 50 degrees above the common boiling
point, viz., 212+50°=262° Fahrenheit; under these circumstances, each
stroke of the plunger, throwing a cubic foot of water into the vaporizing
chamber would cause a development therefrom of about 80 cubic feet of low
pressure steam, the remainder of the injected water falling at once to 212°;
and so for higher pressures and temperatures. A small supplementary force
pump worked by hand, and also by the engine when in action,serves to fill the
heater from the water in before starting, and its continued action while the
engine is working makes up for the deficiency from leakage, or occasional
irregular formation of vapour in the heater, the surplus water escaping into b
through the safety valve k.
The theory upon which this method of vaporization is based, and the objects
attained by its practical application, will sufficiently distinguish it from the
method of Perkins in which the water was superheated to a degree, which
wasexpected to cause its total conversion into steam under a relief of pressure,
and from other boilers in which mechanical circulation of the water is used.
I will now proceed to explain and describe my improvements in applying
the steam in the engine. But previously, in addition to my thermo-dynamical
theory above sketched, I would direct attention to Dalton's laws for mixtures of
vapours and gases, viz., 1st, that the quantity of vapour which saturates any

page_text: space
iven is the same at equal temperatures, whether the space be vacuous
r full of gas; and 2ndly, the elastic pressure of the mixture is equal to the
um of the pressures of both fluids when the initial volume is preserved. I
lso assume, what I believe is generally allowed, that superheated vapors as
ong as they continue dry are perfectly analagous to permanent gases as to
their thermo-dynamic properties.
I have stated in my introductory remarks that wire drawing in the Cornish
engine, and tumultuous expansion in the Woolf system are used with prac-
tical advantage, though in opposition to acknowledged theory, and I have
endeavoured to explain the apparent anomaly on principles which apply more
particularly to common saturated steam. With superheated steam expansion
from direct cut off should be more economical than wiredrawing, and one
cylinder should give a better expansive effect than the Woolf system, that is,
theoretically, but in practice we encounter serious difficulties in applying
superheated steam. If the superheating is sufficient to prevent loss from
condensation in the cylinders with a wide range of expansion we may injure
the working parts of the machinery exposed to this high temperature, and it
becomes a question of importance whether we may not apply extra heat to the
steam during the actual process of expansion, and at intermediate stages of its
progress through the apparatus. For most purposes when high grades of
expansion are used the double cylinder or Woolf system becomes indispensable,
and more particularly in marine engines for the more equable distribution of
the power, and when we perceive upon correct grounds that this system maybe
used without loss of effect, it is not difficult to show how by the application of
correct thermo-dynamical principles a great economy of fuel may be advan-
tageouslyobtained with simplearrangements of mechanism. Takingadvantage
of the fact that within certain limits no loss of effect results from the expansion
of the high pressure steam in the passage between the two cylinders in a
Woolf engine, I make this passage serve the double purpose of a reservoir of
power, and of a heater in which the expanding vapour is superheated by a
steam bath presenting an extensive metallic surface greatly subdivided, and
supplied with steam either from the main boiler when sufficient pressure is
used or from a small independent boiler. As the large cylinder has thus a
reservoir of power expressly its own, and in a manner independent of the small
cylinder, the pistons are not obliged to move simultaneously as in common
Woolf engines, but the cranks may be placed at an angle to each other; about
45 or 135 degrees is the most economical for theoretical effect, and perhaps
sufficient practically for marine engines, in which I avail of this circumstance
to make the large and the small cylinders of one Woolt system act like a pair

page_text: of common engines.
With the arrangement of an intermediate reservoir
acting as a superheater the minute particles of water in mechanical suspension
in the high pressure steam having a high temperature in themselves at the
moment of their escape from the small cylinder are thrown into contact with
the extensive metallic surfaces of the heater maintained at a high temperature
by a constant supply of high pressure steam, and being at the same time
enveloped in an atmosphere of superheated low pressure vapor, or steam gas,
they undergo a very rapid process of vaporization. Here Dalton's laws above
mentioned apply as far as the low pressure steam remains superheated, and
keeping in mind the constant and copious supply of heat offered by the steam
bath we perceive that this condition must generally prevail. Moreover, at the
instant when the high pressure steam mist is injected into the heater each
particle of water contains in itself a quantity of heat sufficient to cause its par-
tial vaporization on the sudden relief of pressure, and hence a flash of steam is
evolved in the heater at each discharge of the small cylinder. This sudden
development of pressure acts with advantage on the large piston, which atthe
moment it occurs has already begun its stroke with the pressure in the reser-
voir, and is impelling its crank with some amount of leverage, while the other
crank is still on the dead point, and acts as a point d'appui to this sudden
impulse of back pressure on the small piston.
The Diagram, marked Figure 2 in the annexed Drawing, illustrates my
improvements in applying the steam in the engine. High-pressure steam in its
common saturated state, or slightly superheated, works in the small cylindera,
as usual, in the Woolf system. The exhaust pipe b conveys the steam
discharged from the small cylinder to the heater d, shown in this case as a
group of inverted syphon tubes enclosed in a steam case e, in communication
with the main boiler, if the steam is sufficiently high, say, not less than three
or four atmospheres, otherwise a small supplementary boiler is used for this
purpose.
The steam descends through the group of tubes on one side of the
arrangement,and ascending on the other passes to the large cylinder f,having
become more or less superheated in its
passage. It is evident that the
arrangement of the heater may be greatly varied, and I would merely remark
that the steam to be heated may pass outside of the tubes, while the steam
which acts as the heating medium passes inside; also that superheated steam
or hot gases from the fire or a hot liquid may be used as heating media. The
heat of vaporization of one pound of steam will raise the temperature of more
than 20 pounds 100° Fahrenheit; it is not, therefore, of much consequence
from what source we derive the superheating caloric, and the economy of
superheating results essentially from the prevention of subsequent loss by con-

page_text: densation and re-evaporation in the cylinder, as explained by me in Weale's
Quarterly Papers in 1843. The heat required simply to dry the steam is in
all cases the equivalent of vaporization of the water mechanically suspended in
the steam.
Saturated steam and superheated steam are sometimes mixed before
admission to the cylinder, but it should be observed that when both fluids are
of equal pressures, the superheated steam by parting with its heat to dry the
steam mist, contracts more in the process than the other expands. If, how-
ever, the superheated steam be of considerably higher pressure than the moist
steam,and if the latter be in the act of tumultuous expansion when the mixture
is made, a good result is obtained, as the mixed steam remains dry, and even
more or less superheated. I obtain this effect in a single cylinder engine by
generating the steam in the boiler at a pressure considerably above the
working pressure, and wiredrawing it into a steam space, into which the
superheated steam (at the pressure of the boiler) is injected; thus, the pressure
in the steam pipe near the boiler being regularly higher than that in the steam
space at the other extremity, gives a point d'appui to the pressure of the
mixed steam; or, in cases where the steam expands tumultuously in the
cylinder itself,as in the Cornish engine, which contracted steam ports, an injec-
tion of steam gas is made directly into the cylinder, the general principle being
to mix the superheated steam with the moist steam in the act of tumultuous
expansion. I apply this principle in the double-cylinder system, by injecting
the high-pressure steam gas into the reservoir between the cylinders above
described, with or without other application of heat to this vessel.
I claim as improvements the preventing of scale in the boiler on the
principle described, and the obtaining comparatively dry steam in a steam
space so small as to cause expansive action in the steam generated at intervals,
as described; and in using the steam in the engine I claim the practical
application of drying and superheating in connexion with my theory of
tumultuous expansion, as illustrated in the several examples given.
In witness whereof, I, the said Maurice Sautter, have hereunto set my
hand and seal, this Sixteenth day of March, in the year of our Lord
One thousand eight hundred and sixty-one.
CK
M. SAUTTER. (L.S.)