IMPROVEMENTS ON MY INVENTION DENOMINATED THE VAPOUR ENGINE, AND THE APPLICATION OF A PART OR PARTS THEREOF, WITH CERTAIN ADDITIONS OR IMPROVEMENTS TO STEAM ENGINES
Year: 1832

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
HOWARD, of Copthall Court, late of New Broad Street, in the City of London,
Merchant, send greeting.
WHEREAS His present most Excellent Majesty King William the
Fourth, by His Letters Patent under the Great Seal of Great Britain, bearing
date at Westminster, the Thirtieth day of November, in the third year of His
reign, did, for Himself, His heirs and successors, give and grant unto me,
the said Thomas Howard, His especial licence, full power, sole privilege and
authority, that I, the said Thomas Howard, my exors, admors, and assigns,
or such others as I, the said Thomas Howard, my exors, admors, or assigns,
should at any time agree with and no others, from time to time and at all
times during the term of years therein expressed, should and lawfully might
make, use, exercise, and vend, within England, Wales, and the Town of Ber-
wick-upon-Tweed, and also in all His said Majesty's Colonies and Plantations
abroad, my Invention of "IMPROVEMENTS ON MY INVENTION DENOMINATED THE
VAPOUR ENGINE, AND THE APPLICATION OF A PART OR PARTS THEREOF, WITH CERTAIN
ADDITIONS OR IMPROVEMENTS TO STEAM ENGINES;" in which said Letters Patent
is contained a proviso that I, the said Thomas Howard, shall cause a par
ticular description of the nature of my said Invention, and in what manner the
same is to be performed, to be inrolled in His said Majesty's High Court'
of Chancery within six calendar months next and immediately after the date
of the said in part recited Letters Patent, as in and by the same, reference
being thereunto had, will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Thomas Howard, do hereby declare, that the nature of my said Invention, and

page_text: in what manner the same is to be performed and carried into effect, is par-
ticularly described and ascertained in and by the following description thereof,
reference being had to the Drawings hereunto annexed, and to the figures and
letters marked thereon (that is to say):-
A cylinder is erected and made secure, to answer in effect that of the steam
engine of Watt, either for single or double action. The present is arranged
for a double-acting engine, the vapour being admitted by valves alternately on
either side of a piston, while it is rapidly withdrawn from the opposite side
by communication with a condenser (afterwards described). A piston rod
passes through the top of the cylinder, and is connected with the machinery
as in other engines. An exterior casing or chamber (A in the Drawing) is
constructed around the working cylinder at a small distance therefrom, per-
fectly air-tight, and communicating with it by means of valves corresponding
to the induction valves of the steam engine. Beneath this chamber and
cylinder, or in other situation when more convenient, (but I prefer placing
it beneath). and forming the lower part of or communicating freely with the
chamber, is the portion of the construction appropriated to the generation of
the vapour, and which is arranged as follows:-A wide shallow vessel (B),
which I recommend to be of wrought iron, is placed over a fire, (such as is
afterwards described, or other), and presents thereto a slightly convex surface.
Other forms or arrangements of this vessel or surface may obviously be employed,
but I prefer the above because it is easy of construction, little liable to be de-
ranged by the heat, and presents the whole or greater part of its exterior to the
fire, so that the heat or flame impinges perpendicularly upon it. Within or upon
the above is fixed a strong sheet or plate of iron (C), having a number of cups
or cylindrical vessels fitted and secured quite tight into it, and proceeding
downwards to within a little distance from the bottom of the vesssel exposed
to the fire. These cups are of wrought iron, and are turned by a lathe, or
otherwise made thin in all parts that are beneath the plate. By this (or it
may be other equivalent) means, a large surface of thin metal, possessing
sufficient stability, is obtained; a tight joint is formed with the chamber at
the circumference of the plate and lower vessel. The intervening space
between these latter is filled with mercury (a yellow shade in the Drawing),
or it may be some other fluid substance, but I prefer mercury because it is
an habitually fluid metal; it transmits the heat in a more perfect and regular
manner than perhaps any other medium, and its specific heat being small, it
requires a comparatively small surface to be exposed to the fire. It is
necessary that all parts in contact with it be of iron. The cups are so arranged
that the greatest number possible can be fixed in the entire area of the hori-

page_text: zontal plate, with only so much of it remaining as will form a steady sup-
port for them. I recommend that nearly three square feet-of generating
surface thus formed, and about one square foot of surface exposed to the
direct action of the fire, be allowed for each horse power of the engine if
worked with water, and if with achohol, or other liquid of rapid vaporization,
a less extent will surfice. It is proper that the mercury should lie in close
contact with the under surface of the plate and cups that it may transmit the
heat rapidly to them, and that no fuame may arise from it; therefore a small
tube (E) is fixed at the highest part of the under surface of the plate. to
prevent the retention of air or vapour beneath it, and communicating with
a vessel or box (F) of cast iron, to receive a portion of the mercury when
expanded by the heat, or other obvious means may be provided for these
purposes. A communication (G) is made between this box and the vapour
chamber above the plate and cups to relieve these last from an unequal
pressure on either side. The box is furnished with an aperture and cover to
allow access to the mercury. A thermometer is passed into the fluid medium
in any convenient manner to point out the temperature thereof, and which
must never be allowed to rise to its boiling point, or, presuming it to be
mercury, about six hundred and fifty degrees Fahrenheit. When achohol
is to be vaporized, I recommend that the temperature of the fluid medium be
about three hundred degrees, and when water, about four hundred degrees,
but considerable latitude may be allowed in this respect without materially
affecting the result. When the heat is rising too high, say approaching five
hundred degrees of temperature, or is sinking too low, say to less than one
hundred degrees above the ordinary boiling point at the vaporizing liquid,
then the intensity of the fire is to be regulated accordingly. In case of its
being desirable to reduce the quantity of mercury otherwise necessary to
render the effect of the fire sufficiently manageable, a part of the space
allotted to it may be occupied by a solid substance, as iron, divided and
arranged so as to partake rapidly of the same temperature, and to interfere
as little as possible with its free circulation. Centrically above the plate and
cups is fixed a nozle (H), so constructed as to disperse the liquid (to be in-
jected through it) in a fine shower as much as possible over them. Any
portion of them not receiving a due quantity of liquid is still useful in adding
heat to the vapour. I recommend that the nozle be a brass hemispherical
vessel with a cap screwed upon it, having a boss that nearly fills it, leaving
only a small space, within all round. The exterior is; pierced with numerous
very small holes, and is screwed to a pipe, through which the liquid is passed,
by means presently described. An opening is made in any convenient part of

page_text: the chamber with a cover which can be removed to give access thereto, and
to the nozle, which last will occasionally require cleansing. The liquid to be
vaporized (a blue shade in the Drawings) is injected at intervals, which I
recommend be as often as and a little before either induction valve is opened,
and in such quantity only as the performance of the engine demands; but not
in greater quantity than will be vaporized, or nearly so, before the next
injection is made. The regulation and admission of the injection is performed
by means of a small sliding valve (I), which is connected with a lever or
handle struck by a cam (or otherwise) through the medium of a piece
attached to the lever, and elevated or depressed by a small screw, so that a
greater or less extent of motion may at any time be given to the slide, and
cause the orifice to remain open for a longer or shorter time, the handle being
returned by means of a weight or spring acting in an opposite direction to the
cam. Or other mechanism may be employed to produce the like effect. A
governor, upon any ordinary construction, is made to affect the action of the
valve when the engine requires self-regulation. If in proper order the
motion of the engine will be very sensable to the adjustment of this valve.
Previously to injection the liquid is heated in a tube (J) which passes through
a vessel (K) full of boiling water. The steam escapes by a waste pipe, the
loss by evaporation being supplied by any suitable method. The liquid may
be heated above the boiling point of water by confining the steam in the
exterior vessel by a safety valve, or the tube (or other vessel) containing the
liquid may itself be exposed to the fire, and be furnished with a safety valve
having a pipe attached to it, which will convey to the chamber the vapour
which passes the valve, and thus prevent a waste of the liquid, the tempe-
rature of which will be limited by the extent of pressure on the valve. The
tube then communicates with a small pump (L), by which it is supplied with
the liquid from the condenser, herein-after described. This pump is worked
by a lever and cam, or other obvious method, in such manner that it shall
be at liberty to perform its working stroke by means of a weight acting
upon it when the injecting valve is opened, the quantity of liquid. injected
being regulated by the motion of the latter, as before described. The pump
is placed below the level of the liquid in the condenser, and is so arrangeḍ
(as shewn in the Drawing) that, although the liquid is nearly in vacuo, it shall
be fully supplied with it, leaving behind any gross accidental impurities. The
vessel containing the mercury, or other fluid medium, has a fire (M) beneath
it (as before mentioned.) Whatever fuel be employed, the fire should be such
as will produce a local heat, and be susceptible of easy regulation. I prefer
the following arrangement, for which coke is the most suitable fuel:-A

page_text: shallow cast iron box (N) is fixed at the bottom of the fireplace, and com-
municates freely with a blowing machine worked by the engine or otherwise.
The top of this box is perforated with many holes, about a quarter of an inch
diameter, or with long very narrow apertures, and about two inches apart,
through which the air passes to the fuel. The box is provided with a hole
and cover at any convenient part for the purpose of occasionally removing the
small quantity of ashes that will fall into it. A valve is placed in the pipe
leading from the blowing machine by which the quantity of air, and, conse-
quently, the intensity of the fire, is adjusted. And when the admission of the
liquid: to be vaporized is subjected to great variation, owing to the nature of
the work to be performed by the engine, it will be convenient to cause the
governor to regulate also the admission of the air to the firo by any ordinary
mechanism. By this means an even and sufficiently intense glow of heat will
be produced throughout the fire, and yet the top of the air box will not become
red hot owing to the continual passing of the air through it. From as many
parts of the fire as convenient there proceed flues by which the hot air
is conveyed to an external casing (0) surrounding the vapour chamber,
and constructed to confime the heat, and pass it as uniformly as possible
around the chamber before it escapes by the common flue or chimney.
The vapour is thus heated considerably in the chamber after its formation,
that its expansive force or volume may be augmented, and that it may be
enabled to sustain it more effectually under an increased specific heat arising
from the expansion to which it is subjected in the working cylinder; for
I recommend that the induction valve be closed at a fourth (or it may be
other portion of the stroke, as in the expansive steam engine of Watt, or
the expansive effect may be produced by diminishing the relative size of
the vapour chamber, but I prefer the former method. The exterior of the
vapour chamber within the flue may be constructed double, and the annular
space thus formed filled with a fluid medium, but this complication is not
required when coke is made use of as above described. A partition is made
within the chamber to lead the vapour to the cylinder valves from the upper
part, as the hotter vapour will naturally ascend. A thermometer is fixed on
this part to indicate the temperature of the vapour. I propose that the entire
contents of the chamber be about the same as that of the working cylinder,
but the proportion is abitrary. A safety valve (P) is attached to the chamber,
and communicates, not with the atmosphere, but with the condenser, and is
loaded, so that the vapour will pass into the latter if it should accidently
.arrive at a greater pressure than is desired, by which means safety is insured
.without loss of vapour. A second safety valve, upon the ordinary construction,

page_text: and more heavily loaded than the former, is added as a further security. The.
pressure may of course be varied, but I prefer obtaining the power of the
engine by a capacious cylinder and moderate pressure, rather than by a small
cylinder and a high pressure. A mercurial or other pressure guage is attached
to the chamber.
In order to start the engine, the injecting pump and valve are worked by
any
convenient hand 1 gear, until a sufficient pressure of vapour is generated
within the chamber. The motion is then commenced by opening the cor-
responding induction and eduction valves, as in the condensing steam engine,
and is continued by the action of machinery upon them, and the other acces-
sory parts of the engine in the usual manner. A capacious pipe leads from
the eduction valves, as in the condensing steam engine. It is curved down-
wards, and the lower part of the curve is formed into a receptacle. for grease
or any accidental dirt, and which may be occasionally removed by a screw
plug. The pipe (Q) is then connected with the vessel (R), in which the
vapour is to be condensed. I recommend that this vessel be cylindrical and
of copper, with a dome upon its upper part, on the top of which is a nozle (S),
to which pipes leading to a small air pump to the chamber safety valve before
described, and to a vacuum guage, are fixed by screw joints. The lower
part of the copper cylinder is attached to a vessel, which may conveniently be
made of cast iron, in one piece. The part of this vessel immediately beneath
the copper cylinder consists of one or more perpendicular oblong tubes (T, T,)
which communicate with a flat or shallow part (T), extending horizontally,
into which two pumps (U, U,) (or one double throwing), are fixed so that they
shall be supplied with liquid from the lower portion of it, yet so as not to
draw up any gross matter accidentally lying there. This arrangement (or it
may be other equivalent to it) is made, that the liquid lying in the lower parts
of the condenser may be cooled by exposure to a considerable surface, that
the pumps may be filled by the pressure of a small height of liquid, and that
they may be free from vapour. In single-acting engines one pump will
obviously be sufficient. These pumps (which are worked by the engine) al-
ternately withdraw the liquid from the lower part of the condenser, and pass
it through a pipe or worm (V), made of copper or other suitable material, and
which is coiled round the condenser at a little distance therefrom, and after
leaving the pumps proceeds downwards, and enters the condenser at the lower
part. It is there furnished with a valve (W.), opening upwards within the
condenser, and a long rod from it it is carried through a stuffing box on the
outside of the nozle, upon the dome before described, which rod is so loaded,
either by a weight or spring, as to cause a moderate pressure upon the valve.

page_text: -
By this means the worm is kept full of liquid, which passing the valve by the
action of the pumps, is thrown upwards and spread by it on all sides of the
condenser, and falls down again with the vapour (admitted into the condenser
from the working cylinder by either eduction valve), instantly reduced by
contact with it into the liquid state. Being now warm, the liquid is partially
cooled in the lower parts of the condenser, and then gradually passing through
the worm by means of the pumps, is effectually cooled before it comes to be
again injected amidst the vapour. The pumps keep up a constant stream, or
nearly so, within the condenser, through the lower valve. The copper cylinder,.
the vessel beneath it, any convenient portion of the pumps, and the entire worm,.
are surrounded with cold water, which is continually pumped by the engine, or
is otherwise thrown into the lower part (as at X<) of a cistern, (or other
vessel) surrounding them, and runs off from the upper part (as at ✗
}
as to flow around the worm in a direction contrary, or as nearly so as may be,
to that of the liquid within it. The described form of the refrigerating vessel;
as a pipe or worm, is not essential, for the same effect will be produced by
any other suitable arrangement exposing a sufficient surface to the external
cold water. The effect of the worm may be increased by flattening it, and
also by dividing it into several branches, but in general I prefer the above
more simple construction. A tube (Y), is fixed within the condenser 'under the
nozle at the top, and proceeds downwards to a little, distance above the valve;
so that the air pump, which is connected with this nozle, will withdraw the air
from near the cold injected liquid, and will consequently take with it as little
vapour as possible. The external pipe leading to the air pump is passed
through the cold water. The air pump is small, its continued action being
required only to exhaust the air which may enter the engine by leakage, and
this should be prevented as much as possible. When alcohol or other valu
able liquid is employed, the air is discharged from the pump into a vessel
exposed on all sides to cold water, and containing some of the liquid through
which the air is passed further to deprive it of vapour. A cock (Z) is pro-
vided at any convenient part of the condenser, to admit or occasionally with+
draw the liquid with which the engine is to be worked, the proper quantity
being ascertained by means of a glass guage.: Previously. to starting the
engine it is partially exhausted of air, either by working: the air pump; by
hand or by blowing through, as practised in the steam engine. The dispo
sition or relative situation of the parts of the engine is not necessarily such
as is represented in the annexed Drawing, which is intended only to elucidate
the description; and the air pump, the cylinder valves, and accessory ma-

page_text: chinery, the construction of WHICH IS ORvious of common wouer engines, a
omitted.
66
Now whereas a former Patent was granted to me, the said Thomas.
Howard, dated the Thirteenth day of October, in the year of our Lord One
thousand eight hundred and twenty-five, and entitled "An Engine which he
"intends to denominate a Vapour Engine, thereby giving Motion by the
Expansive Power of the Vapour of Liquids, particularly such as Evaporate
"at a Lower Temperature than Water, and comprising a New Method of
"Condensation of the Elastic Fluids, and Improvements in the Construction
"of Valves, applicable to the above or other Engines," which method of
condensation and improvements in valves are not included in this my present
improved engine: And whereas in the Specification dated the Fifteenth day
of March, in the year of our Lord One thousand eight hundred and twenty-
'six, appertaining to the said Patent, the following arrangement was claimed
by me, which is in part comprised in this my present improved engine, I now
make no claim thereto, namely,-"The application for the purpose of giving
"motion to machinery of vapour generated from liquids within the cylinder or
"other vessel in which the power operates, the vapour receiving an increase of
expansive power by the heat of the said vessel, particularly when the vapour
"is generated from such liquids as evaporate at a lower temperature than
"water." I disclaim likewise, and from the same cause, the following arrange-
ment, as being essentially the same (the additions or improvements herein
described excepted,) as the process of condensation now forming part of my
improved engine, namely,-"A lifting pump, withdrawing a quantity of the
66
"
liquid from the bottom of the vessel or condenser, injects it into the top of
"the same vessel, after passing it through a pipe or worm, the end of which
pipe, being pierced with many small holes, the liquid is dispersed throughout
"the vessel, and condensing the vapour therein, passes with the condensed
"vapour to the bottom of the vessel. Part of this liquid is again thrown into
"the cylinder by the forcing pump, to be converted into vapour, as before
"described" (in the said Specification), "and part of it is again employed
"to condense the vapour in the manner last before mentioned. In effecting
"the condensation by injection, the condenser and tubes connected therewith
"are immersed in a cistern of cold water, a stream of which is continually
passing through the cistern." And, moreover, I do not claim as new the
employment of a fluid medium interposed between the fire and generating
surface as a regulator of heat, because in the Specification of my former
Patent, above mentioned, I described the same, although under a different
arrangement, and neither did I claim it exclusively therein as a new Invention,
-66

page_text: it having been previously made use of for various purposes. And I hereby
further declare, that my claim for improvements on my Invention, deno-
minated the Vapour Engine, embraces the hercin-before :described new
arrangement or construction thereof (omitting the exceptions above stated)
as comprising the following improvements; and I also claim these im-
provements applied to my vapour engine, either in combination or separately,
namely:-
First, the addition of a chamber to "the cylinder or other vessel in which
the power operates," not confining it to the precise form or position described,
for the purpose of maintaining a supply of vapour, the density of which is
kept up only to the required extent by the repeated injections and vaporiza-
tion of the alcohol, water, or other liquid, and more especially for the pur-
pose of exposing the vapour therein to heat after its formation, in order to
increase its force, and also that it may better sustain the expansive effect in
the working cylinder.
.
Secondly, the process by which the rapid vaporization of the liquid is pro-
moted, being, by means of an increase of surface, combined with the other
herein-before described.
arrangements appertaining thereto, as
Thirdly, the small sliding or other valve by which the liquid injected for
the purpose of vaporization is admitted in the exact quantity required, inde-
pendently of accidental irregularities in the action of the injecting pump, the.
movement of which valve is adjustable either by hand or by a governor.
:
Fourthly, heating the liquid before injecting it, that it may vaporize the.
more rapidly, and that it may not, by a partial condensation or reduction of.
temperature, decrease the elastic force of the vapour already within the
chamber.
Fifthly, the safety valve leading from the vapour chamber to the condenser,
by which any surplus vapour is conveyed to the latter, instead of being lost in
the atmosphere.
Sixthly, the additions to, or improvements on, the before-mentioned process
of condensation, particularly the injection of the liquid from the worm or other
refrigerating vessel or vessels into the condenser from below upwards, so that
it is brought more effectually and for a longer time into contact with the
vapour than when injected directly downwards from above, as was described
under my previous Patent, herein-before alluded to; also the vessel or addi-
tional part attached to the lower portion of the condenser, for the purpose of
partially cooling the liquid therein, of filling the pump or pumps by a hydro-
static pressure, and of preventing any vapour being drawn into them, and the
loaded valve within the condenser at the termination of the worm or other
:

page_text: refrigerating vessel or vessels to produce a pressure upon and prevent the
liquid within it or them from a partial convertion into vapour, caused by its
being nearly in vacuo, and which valve serves also to disperse the liquid
throughout the condenser.
And, lastly, the part, or parts of my vapour engine, of which I claim the
application, with certain additions or improvements, to steam engines, is, the
process of condensation (being essentially the withdrawal of the warm liquid
from the vessel in which the vapour is condensed, and the injecting it again
amidst the vapour, the heat having been in the meantime abstracted from
the liquid), combined with any or all of the additions thereto, or improvements
thereon, herein-before described, from which will result a very rapid and
effectual condensation of the steam, with the advantage of continually employ-
ing in the boiler or generator of steam engines the same water, or nearly so,
and a great reduction in the size of the air pump.
In witness whereof, I, the said Thomas Howard, have hereunto set my
hand and seal, this Thirtieth day of May, in the year of our Lord
One thousand eight hundred and thirty-three.
Inrolled the Thirtieth day of May, in the year of our Lord One thousand
eight hundred and thirty-three.