Iм- PROVEMENTS IN STEAM GENERATORS
Year: 1873

page_text: LETTERS PATENT to William Lloyd Wisc, of Chandos Chambers,
Adelphi, in the County of Middlesex, for the Invention of "Iм-
PROVEMENTS IN STEAM GENERATORS."-A communication from abroad
by Messrs. Louis Marie Théophile Riot and Philippe Roux, of
Paris, France.
t
PROVISIONAL SPECIFICATION left by the said William Lloyd Wise at
the Office of the Commissioners of Patents, with his Petition, on
the 18th June 1873.
I, WILLIAM LLOYD WISE, of Chandos Chambers, Adelphi, in the
County of Middlesex, do hereby declare the nature of the said In-
vention for "IMPROVEMENTS IN STEAM GENERATORS," (a communication to
me from abroad by Messrs. Louis Marie Théophile Riot and Philippe
Roux, of Paris, France), to be as follows:-

page_text: atmospheric pressure, the temperature of its steam is 100%, and its
pressure equals one atmosphere.
The temperature of saline solutions is higher than that of the steam
produced from them, so that if, for example, a solution be formed of
640 grammes of anhydrous chloride of calcium and of 360 grammes of
water, a boiling point will be obtained of 152° at the atmospheric
pressure, at the same time keeping the steam at a temperature of 100°,
and the pressure at one atmosphere. The source of the steam possesses
therefore an excess of temperature of 52° above the steam produced from
it. Now, if after having removed the steam at 100° it be caused to pass
by a serpentine coil through the liquid maintained at 152° it will be
superheated, and on the one hand it will take the 152° temperature of
the bath through which it is made to circulate, and on the other will
retain the pressure of about one atmosphere and a fifth, and the problem
is thus solved of producing regularly and without deterioration of super-
licating apparatus steam of high temperature and of low clastic force.
To effect this the arrangement represented in Fig. 1 of the Drawing is
employed.
A is a close vessel, with a safety valve B lifting at a pressure, for
example, of one atmosphere and five-tenths. C is a box furnished with
a valve; and D a coil, which circulates in the solution contained in the
closed vessel A. This coil is connected by the tube E, furnished with a
cock F, to a coil in the reservoir G containing the liquid to be evaporated
or heated. The bottom of the reservoir G, the level of which is higher.
than that of the vessel A, is furnished with a coil K, which communi-
cates with a valved box L, from which the condense water arising from
the steam which has been utilized for heating or for evaporating is con-
ducted direct to the original bath by the tube M. If the apparatus thus
arranged be used with such a solution as above mentioned, the vessel A
being filled up to the level a, b, when the liquid reaches 152° tempera-.
ture there will be produced steam of 100°, and of one atmosphere pressure.
If the cock F be then opened the valve c', having a pressure from above
higher than one atmosphere, will give passage to the steam, which will
pass along the coil D, the arrangement of which is optional.
The steam isolated from its source by the valve c¹ acquires in the coil
the temperature of the salt bath through which it is obliged to pass, and
which in the present case has a temperature of 152°, at the same time

page_text: attaining a pressure slightly higher than that at its point of departure,
and rejoins by the tube E the coil K placed in the reservoir containing
the liquid to be heated or evaporated. Thus is attained the
rapid heating and in certain cases the evaporation of the liquid in the
vessel G by employing steam at the pressure of one atmosphere and
one-fifth, which only necessitates the tubes of the coil to be of slight
thickness. Hence will be seen the saving of fuel which results from the
employment of these generators in cases where it is desired to heat by
contact, and to obtain steam without pressure. As the saline bath can
have a large surface it is easy to utilize the fuel without allowing the
products of combustion to escape at a higher temperature than is neces-.
sary for the draught.
I have only named for the sake of example the solution of
chloride of calcium and water, as it will be evident that any
other suitable mixture may be used, according to the temperaturo
required. Thus, assuming a temperature of 300° to be required it would
be advantageous to use a double chloride of calcium & zinc, which
would permit the steam to be superheated to 300° with a pressure of
only one atmosphere and two-thirds.
2ND. GENERATION OF SATURATED STEAM AT HIGH PRESSURE WITHOUT
DANGER OF EXPLOSION.
In order clearly to understand the advantage of having saturated
steam at high pressure it will be sufficient to remember that onc
kilogramme of steam at 5 atmospheres contains 652.93 units of heat,
and that at 8 atmospheres one kilogramme of steam at that temperature
contains 658°.60. Thus for 3 atmospheres more it is sufficient to
expend 5.67 units of heat, whereas to pass from 2 to 5 atmospheres
9.65 units of heat have to be expended. But this quantity of heat,
although greater than the first case, would not suffice to give the
preference to high pressures, the saving of fuel not being of sufficient
importance to counterbalance the inconveniences which would arise from
high pressures. The real importance is the point of expansion since
according to the theoretical data the greater the expansion the more
considerable is the amount of work effected, nevertheless by reason of
the accidents which might result from the employment of steam at high
pressure and from the rapid deterioration of boilers pressures beyond
7 atmospheres are rarely employed.
The system of generators for high pressure saturated steam which my

page_text: foreign correspondents have invented is arranged so as to suppress all
danger of explosion whatever may be the pressure of the steam. For
this purpose they employ for example the arrangement represented
in Fig. 2.
A is a closed vessel containing a saline solution, of which we will
suppose for example the boiling point to be 200°, S is the safety valve of
the vessel A. In the solution which forms the saline bath as before,
a chamber B is immersed, into which a feed pump C worked by
machinery brings the water to be evaporated. This water descends in to
the coil D (which is immersed in the saline bath at 200°) and tends to
resume its level at the point d near the place where the coil returns into
the chamber B. But in its course through the saline bath the water
carried at a temperature of 200° yields saturated steam which occupies
the whole of the upper part of B from which it proceeds by the conduit
E to the steam escape F. Now the pressure corresponding to this
temperature of 200° is about 16 atmospheres, and that without danger
of explosion or fear of burning the boilers, since the whole is constantly.
bathed in the solution, and the apparatus is not subjected to the direct
action of the fire. Thus steam at 30 atmospheres could be produced by
employing a solution whose boiling point should be at a temperature
corresponding to that pressure. If it be desired to have perfectly dry
steam it would be sufficient to cause the escape pipe to pass into the
bath before delivering the steam into the cylinder.
I would remark that by means of the coil a large heating surface may
be obtained within a small compass, thereby affording great facility for.
making very strong generators, especially as they are not subjected to
the direct action of fire. It is well to remark that in the two generators
above described the two valves B and S fulfil the office of regulator,
indicating by the escape of steam that the temperature of the bath
exceeds the assigned limit, and that the fire ought to be lowered. The
pressure gauge enables the temperature of the bath to be controlled by
indicating the pressure, so that the fireman by the combined assistance
of the valve and gauge has every requisite indication for easily regulating
the working of this apparatus. Such is the system of steam generators
which my foreign correspondents have invented, and for which Letters
Patent are sought.
It will be understood that I do not limit myself to the precise details
1:C1

page_text: departing from the nature of the Invention which may be briefly stated
to consist in,
..
1st. The employment in steam generators and under the conditions
stated of solutions of matters retarding the boiling point of water and in
which are immersed as in a bath either the serpentine coil shewn in
Fig. 1, destined to produce superheated steam without pressure, or the
boiler and serpentine coil shewn in Fig. 2 furnishing high pressure
saturated steam, so that the parts in which the steam is formed are
never in contact with the fire.
2ndly. The special arrangement of steam generator for producing
steam of high temperature and low elastic force represented in Fig. 1,
principally applicable to heating and evaporating.
3rdly. The special arrangement of generators for producing high
pressure saturated steam in which the reservoir of water to be evaporated.
and its pipes are immersed in the retarding solution which serves at the
same time to heat the water to be evaporated and to avoid explosions.
nied by the said wunam Loya wise in the Great Deal Patent Office
on the 15th December 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
LLOYD WISE, of Chandos Chambers, Adelphi, in the County of Middlesex,
send greeting.
. WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eighteenth day of June, in the year of our
Lord One thousand eight hundred and seventy-three, in the thirty-
sixth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said William Lloyd Wise, Her special license
that I, the said William Lloyd Wise, my executors, administrators, and
assigns, or such others as I, the said William Lloyd Wise, 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

page_text: hereafter, and enables saturated steam of nign pressure to De produce
economically, regularly, and under the most favourable conditions.
I now proceed to treat separately some of the distinctive arrange-
ments, whereby the results above mentioned may be realized.
As these arrangements are essentially variable as to details of con-
struction, I will confine myself to simple Drawings indicating the
principal points which constitute the novelty of this system of
generators..
FIRST. GENERATION OF SUPERHEATED STEAM AT A FIXED TEMPERA-
TURE, AND AT THE MINIMUM PRESSURE FOR THAT TEMPERATURE.
The Invention is based on the fact that the boiling point of water,
which contains in solution either saline matter, glycerine, or other
similar bodies, is higher than that of pure water.
The temperature of pure water is the same as that of its steam, that
is to say, the boiling temperature of water being 100° centigrade at the
atmospheric pressure, the temperature of its steam is 100%, and its
pressure equals one atmosphere.
The temperature of saline solutions is higher than that of the steam
produced from them, so that if, for example, a solution be formed of
640 grammes of anhydrous chloride of calcium, and of 360 grammes of
water, a boiling point will be obtained of 152° at the atmospheric
pressure, at the same time keeping the steam at a temperature of 100°
and the pressure at one atmosphere, the source of the steam possesses
therefore an excess of tempcrature of 52° above the steam produced
from it. Now if after having removed the steam at 100° it be caused
to pass by a serpentine coil through the liquid maintained at 152° it will
be superheated, and on the one hand it will take the 152° temperature
of the bath, through which it is made to circulate, and on the other will
retain the pressure of about one atmosphere and a fifth, and the problem
is thus solved of producing regularly and without deterioration of super-
heating apparatus steam of high temperature and of low elastic force.
To effect this the arrangement represented in Fig. 1 of the Drawings is
employed.

page_text: valve C¹; and D, a coil, which circulates in the solution contained in the
closed vessel A. This coil is connected by the tube E, furnished with
a cock F, to a coil in the reservoir G containing the liquid to be
evaporated or heated. The bottom of the reservoir G, the level of which
is higher than that of the vessel A, is furnished with a coil K, which
communicates with a valved box L, from which the condensed water
arising from the steam, which has been utilized for heating or for
evaporating, is conducted direct to the original bath by the tube M.
If the apparatus thus arranged be used with such a solution as above
mentioned, the vessel A being filled up to the level a, b, when the liquid
reaches 152° temperature there will be produced steam of 100° and of
one atmosphere pressure. If the cock F be then opened the valve C'
having a pressure from above higher than one atmosphere will give
passage to the steam, which will pass along the coil D, the arrange-
ment of which is optional.
The steam isolated from its source by the valve C' acquires in the
coil the temperature of the salt bath, through which it is obliged to pass,
and which in the present case has a temperature of 152°, at the same
time attaining a pressure slightly higher than that at its point of
departure, and rejoins by the tube E the coil K placed in the reservoir
containing the liquid to be heated or evaporated; thus is attained the
rapid heating, and in certain cases the evaporation of the liquid in the
vessel G by employing steam at the pressure of one atmosphere and
one-fifth, which only necessitates the tubes of the coil to be of slight
thickness; hence will be seen the saving of fuel which results from the
employment of these generators in cases where it is desired to heat by
contact, and to obtain steam without pressure. As the saline bath can
have a large surface it is casy to utilize the fuel without allowing the
products of combustion to escape at a higher temperature than is
necessary for the draught.
I have only named for the sake of example the solution of chloride of
calcium and water, as it will be evident that any other suitable mixture
may be used according to the temperature required; thus assuming a
temperature of 300° to be required it would be advantageous to use a
double chloride of calcium and zinc, which would permit the steam
to be superheated to 300° with a pressure of only one atmosphere and

page_text: SECOND. GENERATION OF SATURATED STEAM AT HIGH PRESSURE
WITHOUT DANGER OF EXPLOSION.
In order clearly to understand the advantage of having saturated
steam at high pressure it will be sufficient to remember that one kilo-
gramme of steam at five atmospheres contains 652.93 units of heat, and
that at eight atmospheres one kilogramme of steam at that temperature
contains 658-60; thus for three atmospheres more it is sufficient to expend
5.67 units of heat, whereas to pass from two to five atmospheres 9.65
units of heat have to be expended. But this quantity of heat although
greater in the first case would not suffice to give the preference to high
pressures, the saving of fuel not being of sufficient importance to
counterbalance the inconveniences which would arise from high pressures.
The real importance is the point of expansion, since according to the
theoretical data the greater the expansion the more considerable the
amount of work effected. Nevertheless by reason of the accidents which
might result from the employment of steam at high pressure and from
the rapid deterioration of boiler's pressures beyond seven atmospheres are

page_text: bathed in the solution and the apparatus is not subjected to the direct:
action of the fire. Thus steam at thirty atmospheres could be produced by
employing a solution whose boiling point should be at a temperature
corresponding to that pressure. If it be desired to have perfectly dry
stcam it would be sufficient to cause the escape pipe to pass into the
bath before delivering the steam into the cylinder.
I would remark that by means of the coil a large heating surface may
be obtained within a small compass, thereby affording great facility for
making very strong generators, especially as they are not subjected to
the direct action of fire. It is well to remark that in the two generators
above described the two valves B and S fulfil the office of regulator,
indicating by the escape of steam that the temperature of the bath
exceeds the assigned limit, and that the fire ought to be lowered. The
pressure gauge enables the temperature of the bath to be controlled by
indicating the pressure so that the fireman by the combined assistance
of the valve and gauge has every requisite indication for easily regu-
lating the working of this apparatus. Such is the system of steam
generators which my foreign correspondents have communicated to me
as aforesaid.
It will be understood that I do not limit myself to the precise details
indicated in the Drawings, as they can be modified in many ways
without departing from the nature of the Invention, as respects which I
claim,―
First. The employment in steam generators, and under the conditions
stated of solutions of matters retarding the boiling point of water, and
in which is immersed as in a bath either the serpentine coil shewn in
Fig. 1 for producing superheated steam without pressure, or the vessel B
and serpentine coil shewn in Fig. 2, furnishing high pressure saturated
steam, so that the parts in which the steam is formed are never in
contact with the fire.
Secondly. The special arrangement of steam generator for producing
steam of high temperature and low clastic force, represented in Fig. 1,
principally applicable to heating and evaporating.
Thirdly. The special arrangement of generators for producing high
pressure saturated steam, in which the reservoir of water to be evapo-
rated and its pipes are immersed in the retarding solution, which serves

page_text: at the same time to heat the water to be evaporated and to avoid
explosions.
In witness whereof, I, the said William Lloyd Wise, have hercunto
set my hand and scal, this Fifteenth day of December, in the
year of our Lord One thousand eight hundred and seventy- b
three.