İN- PROVEMENTS IN ENGINES FOR OBTAINING MOTIVE POWER
Year: 1869

page_text: LETTERS PATENT to Francis Alton Calvert, of the City of Manchester,
in the County of Lancaster, Engineer, for the Invention of "İN-
PROVEMENTS IN ENGINES FOR OBTAINING MOTIVE POWER."
Scaled the 23rd November 1869, and dated the 1st June 1869:
PROVISIONAL SPECIFICATION left by the said Francis Alton Calvert
at the Office of the Commissioners of Patents, with his Petition,
on the 1st June 1869.
I, FRANCIS ALTON CALVERT, of the City of Manchester, in the County
of Lancaster, Engineer, do hereby declare the nature of the said In-
vention for "IMPROVEMENTS IN ENGINES FOR OBTAINING MOTIVE POWER," to be
as follows:-
My Invention consists in certain improvements upon the engines
for which Letters Patent were granted to me on the Seventeenth of
October One thousand eight hundred and sixty-four, No. 2555.
My present improvements when applied to a vertical single acting
engine consist in the use of a cylinder open at both ends, having a chest
cast around it for the purpose of supplying the steam or other elastie

page_text: fluid to the piston at about the centre of the length of the cylinder. I
employ any suitable piston combined with what I term a float, which
float is supplied by a tank of water placed below the cylinder; there is a
valve at the lower end of the cylinder to admit the water when a vacuum
is produced by the lifting of the float and to close so as to prevent the
escape of the water when the steam or other clastic fluid is admitted
between the piston and the top of the float. One or more small holes
are made in the cylinder to prevent the float rising beyond a given point.
The float and the water remain stationary while the piston is propelled
to the end of its stroke by the percussive action of the steam or other
elastic fluid aided by the sudden stoppage of the float and water when at
their highest rate of velocity. A sliding valve fitting the interior of the
cylinder is now opened to discharge the water below the float and the
steam or other clastic fluid that was admitted above the float, the reverse
stroke of the piston is effected by the momentum of the fly wheel and
other parts.
My improved valves for admitting and discharging the clastic fluids are
constructed in the following manner:-The seating is made to receive a
hollow taper plug open at both ends. The seating and plug are provided
with holes at proper distances passing through the seating on one side
and through both sides of the hollow plug, the object being to produce
perfect equilibrium of pressure on the plug. The valve so prepared is
applied to the interior of the chest and its holes are brought in line with
the port leading to the interior of the cylinder. Two of these valves are
applied to the cylinder one at each side, the object, being to equalize the
pressure upon the piston as the force is supplied upon the sides of the
piston before it arrives at its ports, thus bringing the crank nearly at its
full leverage before the piston admits the clastic fluid, which fluid is
instantly cut off at any point required. The slide or exhaust valve is
formed in the interior of the cylinder, and is provided with two suitable
port's corresponding with similar ports in the metal of the cylinder;
this valve is both opened and shut at each revolution of the crank by a
tappet.
Anotlier part of my Invention consists in dispensing with the ordinary
throttle valve and applying a taper wedge to a rod actuated by the
governor, this wedge lengthens or shortens the 'catch for opening or
closing blic admission valve.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Francis Alton Calvert in the Great Scal Patent
Office on, the 30th November 1869.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FRANCIS
ALTON CALVERT, of the City of Manchester, in the County of Lancaster,
Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the First day of June, in the year of
our Lord One thousand eight hundred and sixty-nine, in the thirty-
third year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto the said Francis Alton Calvert, Her special licence
that I, the said Francis Alton Calvert, my executors, administrators,
and assigns, or such others as I, the said Francis Alton Calvert, 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 night make, usc, exercise,
and vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
ENGINES FOR OBTAINING MOTIVE POWER," upon the condition (amongst
others) that I, the said Francis Alton Calvert, my executors or adminis-
trators, by an instrument in writing under my, or their, or one of their
hands and scals, should particularly describe and ascertain the nature of
thic 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 Francis Alton Calvert, do hereby
declare the nature of my said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement (that is to say):-
My Invention consists in certain improvements upon the engines for
obtaining motive power, for which former Letters Patent were granted
to me on the Seventeenth day of October One thousand eight hundred
and sixty-four, Number 2555; also iu certain improved valves for
admitting and discharging the steam to and from the cylinder, and in the
machinery for working the valves of motive power engines.

page_text: And in order that my Invention may be fully understood I will
proceed to describe the accompanying Sheet of Drawings, which repre
sents one of my improved engines for obtaining motive power by the aid
of steam, but water or other compressed fluid may be employed instead
of steam,
Figure 1 is an elevation, partly in section, of a compound steam engine
constructed according to my improvements; Figure 2 is a plan, and
Figure 3 is an end elevation of the same, also partly in section; Figure 4
is an elevation of the valve gear,
a, a, are the cylinders, which are open at the top and closed at tho
bottom by the foot valves b, h. The cylinders are secured at each end of
the cistern or tank c, to which are fixed the standards d, d, supporting
the journals of the fly wheel shaft, at each end of which is a disc in
which the crank pins are secured, Within each cylinder a is a piston 4'
connected to the prank pins by the rods. Between each piston a¹ and
its foot valve b is the float 9. The pistons and floats are provided with
spring or other packings of any suitable description. The parts abovo
enumerated are made in the manner described in the Specification of
Letters Patent before referred to. Each cylinder is surrounded by a
steam chest h, to which steam is admitted by the pipe h', see Figures 2
and 3. In each steam chest are the valves for admitting and discharging
tho ateam. The seating of each valve is made to receive a hollow taper
plug marked i, open at both ends; the seating and plug are provided
with holes at proper distances passing through the sonting on one side
and through both sides of the hollow plug, the object being to produce
perfect equilibrium of pressure on the plug. The valves are placed in
the interior of the steam chest, and their holes are brought in line with
the ports leading to the interior of the cylinder, These valves aro
applied at each side of the cylinder, the object being to equalize the
pressure upon the piston, as the force is applied upon the sides of the
plston, before it arrives at its ports, thus bringing the crank nearly at its
full leverage before the piston admits the steam, The cut-off is effected
at any point, as will be described hereafter,
The admission and cut-off valves are worked as follows:-On the fly
wheel shaft is fixed a mitre pinion gearing into a similar pinion on
the upright shaftj. At the lower end of this shaft is another pair of
mitre pinions for driving the horizontal shaft k, on which shaft are fixed
the cams and; the former in revolving acts on the admission valves

page_text: by striking the regulating wedge 1, see Figure 4, fixed to the rack A,
which rack gears into spur pinions fixed to the spindles of the valves i.
The cams are set to cut off at any point by acting on the catch pro-
jecting from the side of the upper rack m. This rack gears into the same
pinions as the rack 4, and brings the valves back to their original
positions. The regulating wedge is raised and lowered by the governor,
as shewn in Figures 1 and 4, and admits less or more steam to tho
cylinder as may be required, At the extremities of the shaft & are fixed
the cams, which act upon studs projecting from the links 12, the upper
ends of which are connected to the levers 72. The slide or exhaust
valves are suspended to these levers by the connecting rods n³. The
exhaust valve ² is to open and close the ports in the lower parts of the
cylinder, and corresponding ports are made in the back plate of the
valye, as shown in the Drawing. These valves are moved near the
termination of each stroke. The foot valve b is a square hollow block
projecting upwards with a valve on each side. These valves are held to
their faces by springs. By this method of constructing the foot valves
a large area is obtained for the admission of the water. o represents a
safety valve of the ordinary construction.
The mode of operation is as follows:-The cylinder in section in
Figure 1 represents the piston and float down and the exhaust valve
closed. As the crank leaves its centre the piston rises, and the float
follows admitting water behind it until the float and piston approach the
admission ports of the valve i, where the full force of the steam is
instantly admitted, and thus gives motion to the piston while the float
and the water remain stationary. The steam is cut off as above de-
scribed. When the stroke is nearly complete the exhaust slide valve n³
is opened to discharge the steam and water. In a compound engiuc, as
shewn, the same operations will be performed in the other cylinder in
the same manner,
Having thus stated the nature of my Invention, and described the
manner of performing the same, I declare that I claim,-
First, The admission valvos marked i, as shown and described.
Secondly. The pinions and racks for working the same, as shewn and
described.
Thirdly. The cams or other equivalents for effecting the positive
cut-off at any portion of the stroke in combination with any admission
valve, as shewn and described,

page_text: governor
Fourthly. The exhaust slide valves n³, as shown and described.
And, Fifthly. The wedge or other equivalent actuated by the
or other regulator for admitting less or more steam to the cylinder, as
shewn and described.
In witness whereof, I, the said Francis Alton Calvert, have hicreto
set my hand and seal, this Twenty-seventh day of November
One thousand eight hundred and sixty-nine.
F. A. CALVERT, (L.S.)