CERTAIN IMPROVEMENTS IN STEAM ENGINES
Year: 1877

page_text: LETTERS PATENT to William Bracewell, of Burnley, in the County of
Lancaster, Engineer and Millwright, and William Pickup, of the same Place,
Manager, for the Invention of "CERTAIN IMPROVEMENTS IN STEAM ENGINES."
PROVISIONAL SPECIFICATION left by the said William Bracowell and
William Pickup at the Office of the Commissioners of Patents on the 7th
March 1877.
WILLIAM BRACEWELL, of Burnley, in the County of Lancaster, Engineer and
Millwright, and WILLIAM PICKUP, of the same Place, Manager. "CERTAIN IMPROVE-
MENTS IN STEAM ENGINES."
Our Invention consists in certain improved arrangements of parts forming either
compound non-condensing steam engines or condensing ones, used either for pumping
or driving machinery.
In all existing direct acting compound engines used either for pumping water
solely or for driving machinery, and having an air pump, such as is used in con-
nection with the condensing apparatus of a condensing engine, the bucket or piston
of the pump being attached to one or other of the piston rods belonging to the
steam cylinders, is actuated at the same speed, and both steam pistons of this de-
scription of an engine moving practically at equal speeds has caused the speed of the
pump pistons to travel at the same rate.
In order to reduce the length of traverse of the pump pistons we connect the
piston rod of the low pressure cylinder to a crank of about twice the throw of that
of the high pressure cylinder, and we increase the area of the high pressure cylinder
in the same proportion; we then connect the pump pistion to the piston rod of the
high pressure cylinder, or in some cases the pump piston may be connected to the
piston rod of the low pressure cylinder, and in this arrangement the area of the
cylinder must be increased in proportion to the reduced length of the stroke. By
this means a slow to-and-fro motion is given to the pump piston which allows for
the efficient working of the pumping apparatus,

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Bracewell and William Pickup in the Great Scal Patent
Office on the 6th September 1877.
WILLIAM BRACEWELL, of Burnley, in the County of Lancaster, Engineer and
"CERTAIN
Millwright, and WILLIAM PICKUP, of the same Place, Manager.
IMPROVEMENTS IN STEAM ENGINES,"
Our Invention consists in certain improved arrangements of parts forming either
compound condensing or non-condensing steam engines for pumping or driving
machinery.
In all existing direct acting compound engines used either for pumping water
solely or for driving machinery, and having an air pump used in connection with
the condensing apparatus of a condensing engine, the bucket or piston of the pump
being attached to one or other of the piston rods belonging to the steam cylinders,
must consequently travel at the same speed.
In order to reduce the length of traverse of the pump piston we connect the
piston rod of the low pressure cylinder to a crank of about twice the throw of that
of the high pressure cylinder, and we increase the area of the high pressure cylinder
in the same proportion; we then connect the pump piston to the piston rod of the
high pressure cylinder. By this means a slow to-and-fro motion is given to the
pump piston which allows for the efficient working of the pumping apparatus.
And in order that our Invention may be fully understood and readily carried
into operation, we will proceed to describe the two accompanying Sheets of
Drawings.
On Sheet 1, Fig. 1, is an elevation, and Fig. 2 a plan of a direct acting horizontal.
compound condensing steam engine constructed according to our improvements. a
is the low pressure cylinder, the piston rod of which is connected in the usual
manner to the crank b; keyed on the crank shaft c and d is the high-pressure
cylinder, to the piston rod of which is fixed the bucket or piston of the air pump e.
The piston rod of the high pressure cylinder, after passing through the air pump, is
connected to the crank pin f, on the crank shaft c, in the ordinary way by a con-
necting rod. The crank b is about twice the throw of the crank f, but the
proportion between the two may be varied according to the maximum speed
required for the piston of the air pump and that of the condensing cylinder, and tho
area of the high pressure cylinder must be increased in the same proportion as the
length of the throw of its crank is reduced.
On Sheet 2, Fig. 3, is a side view, and Fig. 4 a front view of a direct acting
vertical compound condensing steam engine constructed according to our improve-
ments. a is the low pressure cylinder, the piston rod of which is connected to the
crank b; on the crank shaft c and d is the high pressure cylinder, the piston rod of
which passes through the air pump e and is connected to the crank f, as before. All
the working parts of the air pump and condenser and the connections to the
steam cylinders are made in the usual manner.
When engines of the above improved construction are used for pumping water for
fire extinguishing, or for any other purpose where the water does not require to bo
cold, as, for instance, for feeding boilers, the water so pumped can be used for
condensing the steam, thereby saving the power which is otherwise lost by dis-
charging the steam into the atmosphere.
Engines constructed according to our improvements can run at high speeds with
less wear and tear of the air pump and parts connected therewith and with less
liability to breakage and to irregular stoppages.
Having thus stated the nature of our Invention and described the manner of
performing the same, we wish it to be understood that we do not intend to limit
ourselves to the details given, as the same may be considerably varied or modified,
and we claim-Making the cranks of direct acting steam engines of different
lengths, and connecting the air pump piston to the piston rod of the high pressure steam

page_text: cylinder connected to the shorter crank in order to reduce the speed of the air pump
piston, in the manner and for the purposes described.
In witness whereof, we, the said William Bracewell, and William Pickup, have
hereunto set our hands and seals, this Third day of September, One thousand
oight hundred and soventy-seven.
W. BRACEWELL (L.S.)
W. PICKUP.
(L.S.)