IMPROVEMENTS IN INCREASING THE MECHANICAL VALUE OF STEAM AS A MOTIVE AGENT
Year: 1865

page_text: LETTERS PATENT to Benjamin Lawrence, of Coleman Street, in the City
of London, Merchant, for the Invention of "IMPROVEMENTS IN INCREASING
THE MECHANICAL VALUE OF STEAM AS A MOTIVE AGENT."-A communication
from abroad by Thomas Ewbank, of New York, in the United States of
America.
Sealed the 12th September 1865, and dated the 17th March 1865.
PROVISIONAL SPECIFICATION left by the said Benjamin Lawrence at
the Office of the Commissioner of Patents, with his Petition, on
17th March 1865.
I, BENJAMIN LAWRENCE, of Coleman Street, in the City of London,
Merchant, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN INCREASING THE MECHANICAL VALUE OF STEAM AS A MOTIVE AGENT,"
communicated to me from abroad by Thomas Ewbank, of New York, in the
United States of America, to be as follows:-
Steam has two motions, namely, expansion and contraction. High-pressure
or non-condensing engines are operated only by its expansive force; con-
densing engines by both its contraction and its expansion. The present
improvement relates to the latter.
Instead of passing steam after its action on a piston into a condenser
combined with the steam cylinder, I pass it into another cylinder open at top
or one end, so that the atmosphere may press down its piston on the con-
densation of the steam beneath it. By thus separately evolving the contracting

page_text: force a greater amount of it is obtained. In the ordinary system the benefit
of the vacuum is limited to the area of the steam piston, whereas by this
improvement the steam is condensed in a cylinder as much larger than the
steam cylinder as the pressure of the steam exceeds that of common or
atmospheric steam. For example, if the pressure be equal to 15 lbs. per inch
on the safety valve, it will expand and fill an atmospheric cylinder twice as
large; if 30 lbs., three times; and if 45 lbs., four times. Hence the area of
the atmospheric piston increases with the pressure, while that of the steam
piston remains the same under all pressures. By this mode the contracting
force keeps up with the expanding force, and just as much is obtained from
the condensation of the steam as from its direct pressure. By expanding in
the atmospheric cylinder the steam is in a condition more favorable to
condensation than in its previous compressed state, and requires less water to
.condense it.
According to this Invention therefore the condensing apparatus and vacuum
are applied to atmospheric cylinders instead of to the steam cylinders, and
the former are made of larger dimensions than the latter, in or about the
proportions named.
ESPECIFICATION in pursuance of the conditions of the Letters Patent, filed.
by the said Benjamin Lawrence in the Great Seal Patent Office on the
16th September 1865.
TO ALL TO 'WHOM THESE PRESENTS SHALL COME, J, BENJAMIN
LAWRENCE, of Coleman Street, in the City of London, 'Merchant, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Seventeenth day of March, in the year of our Lord
One thousand eight hundred and sixty-five, in the twenty-eighth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said -Benjamin Lawrence, Her special licence that I, the said Benjamin
Lawrence, my executors, administrators, and assigns, or such others as I, the
said Benjamin Lawrence, 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
INCREASING THE MECHANICAL VALUE OF STEAM AS A MOTIVE AGENT,"

page_text: municated to me from abroad by Thomas Ewbank, of New York, in the
United States of America, upon the condition (amongst others) that I, the
said Benjamin Lawrence, 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 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 Benjamin Lawrence, 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, reference being had to the accompanying Drawings, that
is to say:
Steam like other elastic fluids has two motions, namely, expansion and
contraction. High-pressure or non-condensing engines are operated only by
its expansive force; condensing engines by both its expansion and con-
traction. The present improvement relates to the latter class of engines.
Instead of passing steam after its action on a piston into a condenser
combined as usual with the steam cylinder, I pass it into another cylinder
open at top or at one end, so that the atmosphere may press down its piston
as the condensation of the steam beneath it takes place. By thus separately
evolving the contracting force a greater amount of it is obtained.. In the
ordinary system the benefit of the vacuum is limited to the area of the steam
piston, whereas by this improvement the steam is condensed in a cylinder as
much larger than the steam cylinder as the pressure of the steam exceeds
that of common or atmospheric steam. For example, if the pressure of the
steam be equal to 15 lbs. per inch on the safety valve, it would on leaving the
steam cylinder expand and fill an atmospheric cylinder twice as large; if
30 lbs., three times; if 45 lbs., four times. Hence the area of the atmo-
spheric piston increases with the pressure, while that of the steam piston
remains the same under all pressures..
.:
By this mode of condensation the contracting force keeps up with the
expanding force, and just as much is obtained from the condensation of the
steam as from its direct pressure, moreover by its expansion in the atmo-
spheric cylinder the steam is in a condition more favorable to condensation
than in its previous compressed state, and requires less cold water to
condense it
According to this Invention therefore the condensing apparatus and vacuum
are applied to atmospheric cylinders instead of to the steam cylinders, and the

page_text: former are made of larger dimensions than the latter in or about the pro-
portions named.
I proceed with reference to the accompanying Drawings to describe more
particularly the manner in which the Invention may be carried into effect.
Figure 1 is an elevation, partly in section, of machinery constructed for
carrying out the Invention.
A is the working cylinder of a high-pressure engine whose waste steam is
to be converted into power according to this Invention. It may be inclined
vertical or horizontal, fixed or oscillating; its waste pipe c is connected with
the valve or three-way cock d, to admit the steam alternately into the atmo-
spheric cylinders A, B. These cylinders are open at their outer ends, they are
of the same length as A', but each is double of the diameter of the cylinder A¹,
and consequently of each cylinder A, B; its capacity is four times as great.
Their pistons are fixed on the same rod, which works through a stuffing box f.
The closed ends of the cylinders are also connected by the steam valve d and
by the exhausting valve e, which opens and closes passages for the steam from
A and B into the condenser F. The proportions just given between A' and A
and B are calculated for working the former with steam at 60 lbs. to the inch,
so that at every stroke it will fill one of the atmospheric cylinders by its
expansion into common or atmospheric steam, and as the area of its piston is
four times greater than that of A', an amount of atmospheric pressure will be
exerted upon it equal to the expansive force on the piston of A¹. The arrows
indicate the movement of the steam and action of the atmosphere in the
position of the pistons. The passage between A and F being open the
pressure of the atmosphere is exerted on the piston of A by the vacuum in F.
The piston of B is carried forward by that pressure to receive and draw
in at the same time a fresh charge of steam from A¹. As soon as the
stroke is finished the valves are reversed, the atmosphere then presses back
the piston of B and a fresh charge is received into A. The valves are then
again turned, and the operation continued. Both pistons move in the same
direction and simultaneously with the piston of the steam cylinder A¹. The
fly wheel carries the crank over the dead points as usual.
The condensation may be effected by the ordinary process, but in order to
avoid enormous consumption of power by the air pump and its adjuncts, I
prefer when circumstances permit to maintain the vacuum on the principle of
a water barometer, as represented. The pipe p, p, has a perpendicular descent
from the bottom of the condenser to the surface of the water, in which it dips
in an open vessel H of about 35 feet. The vacuum resembles that in the
cylinder of a suction pump placed too high for the atmosphere to receive

page_text: .
water into it. However copious the liquefaction of the vapour or the issue
from the jet the surface of the liquid column cannot stand above a; all the
rest descending and flowing out at H, being discharged without abstracting
any power whatever from the engine. As the air evolved from the water in
the condenser will not be thus got rid of, a syringe or small pump will be
required for the purpose. The quantity in ordinary water is said to vary from
2 to 5 per cent. Taking the latter, a little over 5 per cent. of the power now
expended in the withdrawal of it and the water would be required. The
vapour arising in the vacuum from so small a surface of water as the bore of
the tube presents is inconsiderable, and may be further reduced or its evolution
checked by a thin stratum of oil, which will be but slowly dissipated, as there
is no escape for it except by its descending through the entire length of the
pipe. A cock may be applied to it to keep in the water when the engine
ceases to work. There is no need of its descending in a vertical direction.
It may be turned aside to reach a well, sink, or sewer. It is proper to state
that this mode of maintaining a vacuum is not a new idea; it was proposed
in Arnott's Physics many years ago, but never it is believed put into practice.
To reduce the force absorbed by current condensing machinery, I use water in
the form of ice or snow, because of its greater efficiency than even ice-cold
water. 1 lb. water at 174° added to another at 32° gives 2 lbs. at 87°, but
.with ice instead of cold water the result is 2 lbs. at 32°, and about two-third
of the quantity may be dispensed with, and with it a like proportion of the
force expended upon it. For internal condensation I introduce puffs or jets
of pulverized ice or snow, and for surface condensers square blocks placed in
tapered receptacles formed of hollow partitions containing steam, so that the
blocks as they dissolve may be kept by weights when necessary in close
contact with the partitions. Puffs or jets of pulverulent ice or snow carry
into the condensers less air than water, as the portion of air combined with
ordinary water is discharged in the act of freezing. To prevent premature
condensation of steam in the cylinders A, B, besides enclosing them in non-
conducting wrappers, I introduce into them cylindrical linings of vulcanized
rubber, such as that of which large syringes are now made, and bearing a
temperature of between 300° and 400°.
Figure 1 shows how the contracting force may operate a separate engine,
and be employed on separate work; Figure 2 shews an engine in which both
forces are united in one engine.
A is the steam cylinder furnished with a supply pipe leading from the
boiler. The proportion of A" and the atmospheric cylinders are the same as
in Figure 1; their axes coincide, so that one piston rod carries the three.

page_text: pistons passing through stuffing boxes f. f. There is no waste pipe from A",
because the steam passes directly from it through passages in the valves d, d,
into the cylinders A, B. By the arrows and the channels open in the valves
d, d, and e, the operation will be obvious. The passages between B and the
condenser F being open, the atmosphere is supposed to be pressing forward
the piston of B. At the same time steam is entering A" and forcing its
piston in the same direction, while the steam on the other side of the piston is
entering A and following up its piston. At the end of the stroke the valves are
reversed, and with them the motion of the pistons. In this arrangement there
is no necessity to leave a space between the pistons and ends of the cylinders
for what is called "clearance," and a material amount of steam hitherto
wasted is saved, there being no chance that the water which remains in the
cylinders will arrest the motion of the pistons near the end of the stroke.
Condensers on the plan of water barometers applied to steam vessels would
save machinery and. power. There is no obstacle to be overcome at all
commensurate with the gain. Given the requisite elevation and the power
expended on them would virtually be confined to the supply of cold water.
Condensing in the ascending exhaust pipe would have to be guarded against
to prevent the water entering the cylinders, but as it would trickle down the
sides it might be received in an enlarged part or receptacle at the bottom, and
withdrawn thence by a syringe or small pump without affecting the vacuum.
As the condenser retains no water its weight presents no grave difficulty in
securing it. The smoke pipe itself might be used for its support. The
condenser is applied to engines in the manner shewn in Fig. 8, where
sufficient depth below them for the water barometer is not easily attainable.
Fig. 3 shows the connexion of the vacuum pipe with the exhaust valve of
the atmospheric cylinders. The ascending vacuum pipe O is enlarged at H,
to prevent steam condensed in O from running back into the cylinders. The
pipe from the valve rises a short distance into H, and the lower end of the
rest enters at the opposite side, so that water falling from it may fall clear of
the other, and collecting below may be withdrawn by the small pump P.
Most land engines have some means of discharging the water from the
barometer below them, and consequently only require the balance of the tube
to be carried above them.
Having now described the nature of the said Invention, and in what
manner the same may be performed, I declare that I claim,-
First, increasing the mechanical effect of steam by atmospheric cylinders in
connexion with steam cylinders, substantially as described.
Second, the application of the condenser described to steam engines by

page_text: continuing the exhaust steam pipe sufficiently above the engine to connect
with it.
In witness whereof, I, the said Benjamin Lawrence, have hereunto set
my hand and seal, this Thirtieth day of May, in the year One thousand
eight hundred and sixty-five.
Witness,
M. HENRY,
Patent Agent,
84, Fleet St.,
London.
BENJEN. LAWRENCE. (L.s.)