IMPROVEMENTS IN STEAM ENGINES
Year: 1874

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields,
in the County of Middlesex, Gentleman, for the Invention of
"IMPROVEMENTS IN STEAM ENGINES."-A communication from abroad
´by William Brown Reaney, of Philadelphia, Pennsylvania, United
States of America.
Sealed the 21st May 1875, and dated the 15th December 1874.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson
at the Office of the Commissioners of Patents, with his Petition,
on the 15th December 1874.
I, JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County
of Middlesex, Gentleman, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN STEAM ENGINES," a communication to
mẹ from abroad by William Brown Reaney, of Philadelphia, Penn-
sylvania, United States of Amèrica, to be as follows :—
This Invention relates to what are known as compound engines, or
engines having a high-pressure and a low-pressure cylinder, and consists
in forming, by means of a valve connected to the governor, a vacuum in

page_text: all parts of the cylinders, both high and low pressure, and in their con-
nections at the time the high-pressure governor valve has completed its
functions, the governor thus being employed for controlling the low-
pressure or large cylinder of the engine, and the working parts being
relieved of all strain.
The Invention is applicable to existing engines of the class before
referred to as well as to engines to be hereafter constructed.
In carrying out this Invention it is proposed to employ a vacuum
valve having an area of opening of, say about 1/8th of that of the steam
pipe on a high-pressure cylinder. This valve is bolted to a receiver
between the high-pressure and the low-pressure cylinder, or in the pipe
connecting the two cylinders, and is placed in connection with whatever
arrangement may be adopted for conveying the steam from the small to
the large cylinder. The design of valve should be of such character as
to be easily worked by the governor and to be perfectly tight when
closed.
A convenient mode of arranging the valve is to provide one opening
leading into the chamber or connecting pipe between the cylinders and
a pipe leading to the steam chest on the high-pressure cylinder, and also
another pipe leading from the opposite opening of the valve to the
exhaust pipe of the low-pressure or large cylinder.
In connecting the governor with this valve the links and rods are
arranged in such a manner as not to operate the vacuum valve until the
valve on the high-pressure cylinder has nearly closed, for until that time
the valve on the high-pressure cylinder will perform the duty of a
regulating the engine, but as soon as it has closed, say ths of the
opening, then the governor is allowed to act upon the vacuum valve, by
opening which a vacuum is instantly formed on the steam side of both
pistons. By this means all the steam pressure is taken off both pistons,
and the whole of the parts are entirely relieved from strain.
In constructing a valve for this purpose it is preferred to adopt one
that would work the whole throw of the steam valve, but having the
openings so arranged that it should open only as the steam valve is
closing. This may be effected by arranging the valve in the following.
manner, viz. The valve is made in the form of a hollow cylinder, and 3
is mounted on a spindle which is connected with the governor and its
valve by a bell-crank lever arrangement. In the sides or walls of tho

page_text: valve there are formed a suitable number of perforations which corre-
spond with similar perforations provided in a cylindrical casing
surrounding the valve, and in contact with which it works. This valve
casing is in communication with the several pipes or connections, and
the valve is opened or closed by the perforations in the valve being
brought opposite to the perforations in the casing or opposite the metal
between the perforation in the casing, as the case may be.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Henry Johnson in the Great Seal Patent
Office on the 11th June 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of
Middlesex, Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Qucon Victoria, by Her
Letters Patent, bearing date the Fifteenth day of December, in the year
of our Lord One thousand eight hundred and seventy-four, in the
38th year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said John Henry Johnson, Her special
license that I, the said John Henry Johnson, my executors, admi-
nistrators, and assigns, or such others as I, the said John Henry
Johnson, my executors, administrators, or 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," a communication to me from abroad
by William Brown Reaney, of Philadelphia, Pennsylvania, United
States of America, upon the condition (amongst others) that I, the
said John Henry Johnson, my executors.or administrators, by an instru-
ment 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 immic-
diately after the date of the said Letters Patent.

page_text: NOW KNOW YE, that I, the said John Henry Johnson, 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, reference being had to the accompanying
Drawings, and to the letters and figures marked thereon, that is to
say:-
The said Invention consists of an arrangement by which the governor
can be used to control the low-pressure or large cylinder of compound
engines. This arrangement, which is particularly adapted for compound
marine engines, is capable of being attached to any governor now in
use on this class of engines.
According to the said Invention a vacuum valve is employed, such
valve having an area of opening which need not exceed twenty per
cent. of the area of the steam pipe on a high-pressure cylinder. This
valve is bolted to a receiver between the high-pressure cylinder and the
low-pressure cylinder, or in the pipe connecting the two cylinders. In
order to act it should be placed in connection with whatever arrange-
ment may be adopted for conveying the steam from the small to the
large cylinder. The valve employed should be of such a character as
to be easily worked by the governor, and to be perfectly tight when
closed.
And in order that the said Invention may be fully understood I shall
now proceed more particularly to describe the same, and for that purpose
shall refer to the several Figures on the annexed Sheet of Drawings, the
same letters of reference indicating corresponding parts in both the
Figures.
'
Figure 1 of the accompanying Drawings represents a. side elevation,
and Figure 2 is a half horizontal section and half plan of a portion of a
compound engine having the improvements which form the subject of
the said Invention applied thereto..
A is the high-pressure cylinder; B is the low-pressure cylinder; C is
the receiver; and D is the vacuum valve.
The vacuum valve D may be arranged as shewn in the Drawing, its
valve box D communicating with the connecting pipe a from the
receiver C with the pipe b which leads to the steam chest E on the high-
pressure cylinder A, and from its opposite opening c with the exhaust
pipe F of the low-pressure or large cylinder B.

page_text: In connecting the governor with this valve the connections are
arranged in such a manner as not to operate the vacuum valvo D until
the valve G on the high-pressure cylinder A has nearly closed, for until
that time the valve on the high-pressure cylinder will perform the duty
of regulating the engine; but as soon as it has closed, say seven-eighths
of the opening, then the governor is allowed to act upon the vacuum
valve D, by opening which a vacuum is instantly formed on the steam sido
of both pistons. By this means all the steam pressure is taken off both
pistons, and the whole of the parts are entirely relieved from strain.
In constructing a valve for this purpose it is preferred to adopt onc
that would work the wholo throw of the steam valve, but having the
openings so arranged that it should open only as the steam valve is
closing. This may be effected by the use of a valve of the description
shewn on the Drawing, or one of similar construction. Engineers in
applying this improvement will readily see the necessity for this and
also the means of adapting it.
In the arrangement shewn in the Drawing the valve consists of a
tube or hollow cylinder mounted on a spindle e, and having formed in
its walls or sides perforations f, f, which correspond with similar per-
forations g, g, provided in a casing or seat / surrounding the valve and
in contact with which the valve works. The valve spindle e carries a
lever arm or crank i attached to one end of a connecting rod k, the
opposite end of which is jointed to one arm of a bell-crank lever 7; this
lever is mounted on the spindle m of the valve G, and its other arm is
connected to a rod n leading to the governor, so that the governor is
caused to turn the valve D simultaneously with its action upon the
valve G. The valve D is opened by the perforations f,f, being brought
opposite to the perforations g, g, in the seat h, and closed by such per-
forations f,f, being brought opposite to the solid portions of the said scat
situate between the perforations g, g.
Having now described and particularly ascertained the nature of the
said Invention, and the manner in which the same is or may be used or
carried into effect, I would observe in conclusion that what I consider to
be novel and original, and therefore claim as the Invention secured to
me by the herein-before in part recited Letters Patent is, placing
vacuum in all parts of the cylinders, both high-pressure and low-
pressure, and the connections at the time the high-pressure governor

page_text: valve has completed its functions by means of a valve connected to the
same governor, and thus relieving the working parts of all strain, as
berein-before described.
In witness whereof, I, the said John Henry Johnson, have to
this my Specification set my hand and seal, the Eighth day of t
June One thousand eight hundred and seventy-five.
berein-before described.
In witness whereof, I, the said John Henry Johnson, have to
this my Specification set my hand and seal, the Eighth day of
June One thousand eight hundred and seventy-five.