IMPROVEMENTS IN STEAM ENGINES
Year: 1854

page_text: LETTERS PATENT to William Frost, of Wine Office Court, Fleet Street,
in the City of London, Engineer, for the Invention of "IMPROVEMENTS IN
STEAM ENGINES."
Sealed the 20th March 1855, and dated the 5th October 1854.
PROVISIONAL SPECIFICATION left by the said William Frost at the
Office of the Commissioners of Patents, with his Petition, on the
5th October 1854.
I WILLIAM FROST, of Wine Office Court, Fleet Street, in the City of
London, Engineer, do hereby declare the nature of the Invention for
"IMPROVEMENTS IN STEAM ENGINES" to be as follows:-
My improvements are principally applicable to engines where surcharged
or heated steam is employed, and consists in using a vessel or vessels which
are placed between the cylinders and condensers, and so constructed that the
steam, after leaving the cylinders in its passage to the condensers, gives out
the free caloric while passing through the vessels before it enters the con-
densers; by this I am enabled to re-evaporate a large quantity of steam of
the same density as that contained in the boilers, and which enters the steam
pipe or boiler, to be used again in connection with the steam generated in the
boilers. I also use in, connection with the re-evaporator, and between it and

page_text: "
the condensor, a small cylinder or vessel, into which the "feed water is
injected, and falls upon a number of plates, perforated, that it may be diffused
large surface, and so kept until the steam has heated it up to as high a
temperature as the state of the vacuum will admit. Into this vessel only
the "feed" water is admitted, and that portion of the water that may have
become condensed in the re-evaporator, which becomes part of the feed
The feed water is drawn out of the heating vessel by a pump, and
forced to the boilers in the ordinary way. It is not essential to this part of the
Invention that it should be used with the other parts.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Frost in the Great Seal Patent Office on the
5th April 1855.
TO ALL TO WHOM THESE PRESENTS SHALL COME, J, WILLIAM
FROST, of Wine Office Court, Fleet Street, in the City of London, Engineer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fifth day of October, in the year of our Lord
One thousand eight hundred and fifty-four, in the eighteenth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said William Frost, Her special licence that I, the said William
Frost, my executors, administrators, and assigns, or such others as I, the
said William Frost, my executors, administrators, and assigns, should at
any time agree with, and no others, from time to time and at all times there-
after 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 "IMPROVEMENTS
IN STEAM ENGINES," upon the condition (amongst others) that J, the said
William Frost, by an instrument 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 William Frost, do hereby declare
the nature of the said Invention, and in what manner the same is to be

page_text: performed, to be particularly described and ascertained in and by the following
statement thereof (that is to say) :-
:-
It is well known that when common steam has been used in the condensing
engine, either expansively or not, the steam, after having done its work in the
cylinder, passes direct to the condenser, and that only a small portion of the
whole volume of caloric passed through the engine that is returned to the boiler
is that which the feed water contains, and taken from the waste delivered by
the air pump. It is also well known that in the high pressure engine, working
expansively or otherwise, the proportion of the whole volume of caloric absorbed
for re-evaporating purposes after the steam has left the cylinder is very small,
being only that which the feed water takes up in passing through the heater.
Now, my improvements consist in applying apparatus, as hereafter described, to
obtain back a much larger quantity of the caloric from the steam, whether
superheated or simple steam combined, or otherwise, be employed in working
an engine. In a low pressure or condensing engine I apply what I call an
attemperator, as shewn in the accompanying Drawing (Figure 1). A is the
attemperator. This boiler is made of the required form, and contains a con-
siderable surface, say, one-third of the total evaporative surface in the boilers
used for the engine. B is what I call the feed water heater, which contains a
series of inverted plates, perforated with small holes; it is shown in section in
Figure 2, letter B. The steam is passed through the attemperator A, after it
has done its work in the cylinder D, through the eduction pipe E, and into the
space C, which connects all the tubes, and being of a much higher degree of
temperature than the steam in the boilers (before it is superheated), in its
passage through the tubes imparts its caloric in excess of the lower tempera-
ture to the surrounding fluid, and generates a new volume of steam, which is
returned through the connecting pipe F, with a valve fitted to prevent any
steam from coming in the opposite direction from the steam pipe in boilers.
L is the feed pipe to supply the attemperator; I is the division plate.
After the steam has passed through the attemperator, it enters the feed water
heater B, on its passage to the condenser H, and is made to eat up the feed
water for boiler and attemperator. The water for feed is drawn into the
heater B from the waste box I through the pipe K, and falling upon the
plates L, L, L, (which are pierced with small holes) is kept in small particals
for a sufficient length of time to be acted upon by the exhaust steam, and,
falling down into the reservoir, is conveyed to the feed pump through the
pipe M; the rest of the steam escapes into the condenser in the ordinary
way.

page_text: In many engines it may not be convenient to have a separate attemperator,
and in that case boilers A' can be so constructed as to contain the evaporative
surface, as shewn in Figure 3, side vertical sectional view, the outside water
leg being made wide enough to contain the pipes A, A². On the end nearest
the engine is placed the entrance chamber G, connecting all the pipes with a
division I, which will cause the steam to circulate in the direction of the
arrow, shown, and return to the condenser through the pipe B, and thence to
the water heater, as before described. D is the eduction pipe from cylinder;
E, steam pipe from superheater; F, common steam pipe. Figure 4 is a
front elevation of Figure 3, showing the case removed, that the attemperating
pipes A may be seen. A¹, the boiler; G, chamber covering the tubes;
C, C, furnace doors; D', smoke box; E', E', ash box. By using the water
heater B, it will be seen that I obtain the feed water at the highest tempera-
ture instead of the mean, as at present,..in the condensing engine, and a saving
of several degrees will be effected, whether using superheated steam, common
steam combined, or separate, for the purpose of heating the feed water alone or
in connection with the attemperator.
The attemperator, when using superheated steam alone. or in combination
with common steam, will only take up the surplus caloric that is in excess of
the steam in the boiler, which, if the surface be sufficient, will be found to
correspond with the relative temperature.
In high pressure engines, the superheated steam or combination with
common steam is passed through the attemperator after it has done its work
in the cylinder (and if preferred the attemperating surface may be placed in
the boiler), when the excess of caloric will evaporate the surrounding fluid,
the steam from which is carried away, as before described. The steam on
leaving the attemperator is then to heat the water for feed of boiler and
attemperator in the ordinary way, by worm, double cylinder, or cistern, or
the like.
I do not confine myself to this arrangement of the mechanical parts for
carrying out my Invention, as the attemperating surface may be placed in
various ways, and the heating of the feed water for low pressure engines may
be accomplished by causing the water to be thrown in at stated times into a
separate cylinder at the moment of exhaust steam entering the separate
chamber.
I do not claim the use of superheated steam; but what I do claim is, the
passing of superheated steam, alone or in combination with common steam.
through an attemperating surface, as described; and I also claim the water

page_text: heating in a separate chamber for feed in condensing engines, with either
heated or common steam in combination with or without an attemperator, in
the manner described. .
In witness whereof, I, the said William Frost, have hereunto set
my hand and seal, this Fifth day of April, in the year of our
Lord One thousand eight hundred and fifty-five.
Witness,
JOHN EDKINS.
WILLIAM FROST. (L.S.)