IMPROVEMENTS IN STEAM ENGINES
Year: 1862

page_text: LETTERS PATENT to Benjamin Thompson, of Walker, near Newcastle-
upon-Tyne, for the Invention of "IMPROVEMENTS IN STEAM ENGINES."
Sealed the 25th September 1862, and dated the 5th April 1862.
April 1862.
atents, with his retition, on the 5th
I, BENJAMIN THOMPSON, of Walker, near Newcastle-upon-Tyne, do hereby
declare the nature of the Invention for "IMPROVEMENTS IN STEAM ENGINES," to
bo as follows:-
The following preliminary remarks, by explaining the object intended, will
assist in rendering more explicit the precise nature and definition of my
Invention.
It is well known that the combination of high-pressure power with vacuum
power, though frequently attempted has hitherto failed of so satisfactory a result
as might be desired in consequence of the large amount of condensed steam
which has been created requiring a large expenditure of pumping power, and
therefore of fuel for its removal, and consequently a large deduction from the
gross power of the engine. It is my object to relieve the engine of the unprofit-
able deduction due to this cause, and to condense a portion only instead of the
entire quantity of high-pressure steam with which it has been served, or in
other words at or near the end of the stroke to allow freely to escape so much
of the high-pressure steam as will leave the remaining steam in the cylinder of

page_text: only about the atmospheric pressure, and to condense this remainder only
instead of the entire quantity.
Having thus explained my object I define my Invention as the constructing
steam engines for the combined use of high-pressure power and vacuum power
with slides or valves so arranged or disposed as to effect the division of the
steam with which the engine is served into separate portions after such steam
shall have given out its pressure power as distinguished from its vacuum
power, and so that a portion shall be suffered to escape, and a portion may
become condensed.
It is evident that this my Invention may be carried into effect not only by
the constructing of entirely new engines but also by alterations to those or
some of those as hitherto constructed, more particularly in respect of the valves
and the steam ways through which the cylinder is served.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Benjamin Thompson in the Great Seal Patent Office on the
3rd October 1862.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, BENJAMIN
THOMPSON, of Walker, near Newcastle-upon-Tyne, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fifth day of April, in the year of our Lord One
thousand eight hundred and sixty-two, in the twenty-fifth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Benjamin Thompson, Her special licence that I, the said Benjamin Thompson,
iny executors, administrators, and assigns, or such others as I, the said
Benjamin Thompson, 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 "IMPROVEMENTS IN
STEAM ENGINES," upon the condition (amongst others) that I; the said
Benjamin Thompson, my executors or administrators, by an instrument
in writing under my, or their, or one of their hands and seals, should par-
ticularly 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 immédiately
after the date of the said Letters Patent.

page_text: NOW KNOW YE, that I, the said Benjamin Thompson, 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 thereof, that is to say:-
The following preliminary remarks by explaining the object intended will
assist in rendering more explicit the precise nature and definition of my
Invention.
It is well known that the combination of high-pressure power with vacuum
power, though frequently attempted, has hitherto failed of so satisfactory a
result as might be desired in consequence of the large amount of condensed steam
which has been created requiring a large expenditure of pumping power, and
therefore of fuel for its removal, and consequently a largo deduction from the
gross power of tho engine. It is my object to relieve the engine of the
unprofitable deduction due to this cause, and to condense a portion only instead
of the entire quantity of high-pressure steam with which it has been served, or
in other words at or near the end of the stroke to allow freely to escape so
much of the high-pressure steam as will leave the remaining steam in the
cylinder of only about the atmospheric pressure, and to condense this remainder
only instead of the entire quantity.
Having thus explained my object I define my Invention as the constructing
steam engines for the combined use of high-pressure power and vacuum power
with slides or valves, so arranged or disposed as to effect the division of the
steam with which the engine is served into separate portions after such steani
shall have given out its pressure power as distinguished from its vacuum power
and so that a portion shall be suffered to escape, and a portion may become
condensed.
It is evident that this Invention may be carried into effect, not only by the
constructing of entirely now engines, but also by alterations to those or some
of those as hitherto constructed, more particularly in respect of the valves and
the steain ways through which the cylinder is served.
In the accompanying Drawing, Figures 1 and 2 are sectional elevations,
and Figure 3, a plan view of the nozzles, valves, chests, and other parts of a.
high-pressure condensing steam engine constructed in accordance with my
Invention. For the convenience of illustration, those parts which characterize
the novelty are tinted red, and those which are old are tinted blue, and where
similar letters occur in the various Figures, they are employed to denote corre-
sponding parts.
A is the cylinder; B, piston rod, and C, piston; D, D, D, are steam pipes,
and E, F, upper and lower steam chests constantly open to the boilers; Gand

page_text: H are the upper and lower steam valves opening into the upper and lower
steam chests I and K respectively, which communicate with the steam ports
of the cylinder; G* and H* are the upper and lower exhaust valves between
the chambers I, K, and the eduction pipes L, M, and N. The last-mentioned
pipe communicates with the two new valves O and P, which are so worked as
at Q, in Figure 2, that while either is open, the other is shut. They divide
the steam into two separate portions after it has left the cylinder and
given out its pressure power, the first and larger portion passing off by the
new valve O, through the passage R (the valve P being closed), and the
remainder and smaller portion afterwards passing by the valve P through the
passage S to the condenser (the valve O being closed). The movement of the
valves may be effected by any convenient means, and the new exit valve O
should be opened simultaneously with the closing of the new exhaust valve P,
and also simultaneously with and each time that either of the exhaust
valves G* or His opened, and the arrangement should be such that the
valve each time it is opened should remain opened but a very short
time for the escape of the waste high-pressure steam (scarcely more than an
instant) and should be suddenly opened and again be suddenly closed. The
action of the engine will then be as follows:-Supposing the valve G opened,
the steam will rush through the chest I and through the upper steam port
(coloured black in the Drawing) into the cylinder, and above the piston, which
will be forced downward till at very nearly the termination of its stroke the
valve G is to be closed, and at the same time the valves G* and O are to be
suddenly opened, and the valve P consequently closed. So much of the high-
pressure steam as in excess of the atmospheric density will then very rapidly
discharge itself through the waste pipe R, when the valves G* and O are to
be suddenly closed, and the exhaust valve P consequently opened to the con-
denser. This completes one down stroke of the engine. For the up stroke
the valve H is to be opened, and at nearly the termination of the stroke to be
closed, at the same time opening the valves H* and O, and again almost
immediately closing them, the valve P meanwhile being momentarily shut and
again opened.
The following statement of the advantages I anticipate realizing by the use
of my Invention will further assist the elucidation of the subject. Assuming
high-pressure steam to enter the cylinder with an effective pressure of twenty
pounds per square inch, and assuming further that the vacuum power derivable
from condensation is (as usually reckoned) about ten pounds per square inch,
I obtain a combined force of thirty pounds, thus firstly increasing threefold the
power of a condensing engine; secondly, saving one-third of the steam, and

page_text: further uniting the principles of two descriptions of engines in one machine,
and thereby obtaining economical results. In illustration of these, an engine
of 150 horse-power may be constructed as a condensing engine of 50 horse-
power with the working parts increased in strength sufficiently to resist the
strain of a 150 horse-power engine. The boiler provision should be high-
pressure boilers capable of yielding steam for a 100 horse-power engine.
From the foregoing description and statements it will be seen that not only
may new engines be constructed in accordance with my Invention, but existing
condensing engines may be adapted for the purpose, if possessed of sufficient
strength to resist the increased strain; and also existing high-pressure engines
may be adapted for the purpose, if an air pump and condenser be added.
In witness whereof, I, the said Benjamin Thompson, have hereunto set
my hand and seal, this First day of October, in the year of our Lord
One thousand eight hundred and sixty-two.
BENJN. THOMPSON. (L.B.)