IMPROVEMENTS IN STEAK ENGINES AND BOILERS
Year: 1869

page_text: LETTERS PATENT to James Henry Bennett, of Leith, in the County
of Mid Lothian, North Britain, for the Invention of "IMPROVEMENTS
IN STEAK ENGINES AND BOILERS."
Sealed the 14th September 1869, and dated the 17th March 1869
PROVISIONAL SPECIFICATION left by the said James Henry Bennett
at the Office of the Commissioners of Patents, with his Petition, on
the 17th March 1869.
I, JAMES HENRY BENNETT, of Leith, in the County of Mid Lothian,
North Britain, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN STEAM ENGINES AND BOILERS," to be as follows:-
This Invention so far as it relates to steam engines comprises certain
In constructing
improvements in surface condensers and slide valves.
a surface condenser according to this part of my Invention one end of
the tubes, namely, that which is furthest from the steam inlet pipe, is
secured into an elastic tube plate composed of india-rubber or other
suitable elastic material in order that the several tubes may be free to
expand or contract either together or independently, thus obviating the
difficulty of keeping the connections tight and in good working order.

page_text: A template may be used inside the india-rubber tube plate to facilitate
the removal or replacing of any of them, and doors may be used to afford
access to the tubes, or the two tube plates and tubes may be withdrawn
bodily for cleaning or repairs.
The improvements in slide valves consists mainly in the arrangement
of two cylinders, high and low pressure or otherwise, with one valve
chest only common to both cylinders conducting the steam from the
first cylinder to the second. The steam is passed into the first cylinder
from the inside of the slide valve, then through the valve chest to the
second cylinder, from which it is exhausted through the inside of the
second slide valve and carried to the condenser or atmosphere. The
movement of each valve is independent, and the pressure of *steam may
be entirely removed from the slide valves by the interposition of two
loose back plates adjusted by a double-faced wedge and screw to keep
a steam-tight face on both sides of the valves. This adjustment is
assisted by two side bearers which may be used for either one or both
slide valves to prevent the possibility of their being set fast by improper
movement of the double-faced wedge. The setting of the bearers may
be done from the inside of the chest if preferred, in which case no
possible movement of the double-faced wedge. could jam the valves.
Altho' preferred it is not necessary that either or both the slide valves
should be open through to the back plates, as the valves might be close
on the back and any escape of steam by these faces prevented.
The essential features of this part of my Invention are, 1st, the direct
passage of steam from one of two combined cylinders to the other and
thence to the condenser or atmosphere through one valve chest only
common to both cylinders and two slide valves working independently;
and, second, the so connecting the slide valves by interposed plates
and wedge surfaces, combined or not with the bearers herein-before
mentioned as may be required, that the pressure of steam or vacuum shall
be entirely or partially removed from the valves, thus reducing the
friction of the faces and moving parts; also the peculiar arrangement of
parts whereby correctness in adjusting the steam and other faces is
ensured without risk of seizing or setting the valves fast. Separate
expansion valves may be used in connection with these combined valves
when desired. A similar arrangement of back plate and wedge may be
adapted to single slide valves for removing the pressure from them.

page_text: Another improvement in slide valves consists in keeping the steam
pressure from the back of the slide valve by means of the valve chest
door itself, which may be made circular or any other convenient shape
with a gland and elastic packing to keep the chest steam-tight. This
packing may be used to press the inside surface of the door up to the
back of the valve, or it may be used simply as a steam-tight gland, and
the valve chest door tempered up to the valve by other means of
adjustment, as, for example, by a central bolt secured to the cylinder
face and passing through the slide valve and the door, or the central
bolt may be outside, supported by a cross bar or bearer secured to the
valve chest and through which the bolt is screwed and adjusted by a set
nut.
An opening may be arranged from the space at the back of the
slide valve mounted with a valve or other indicator to shew if any
pressure is there to allow the steam to pass away and to warn the
engineer that adjustment of the door is required. From the diminished
number of bolts in the absence of a faced joint greater facility is given in
removing and replacing the valve chest door when required. As already
stated in reference to the combined valves the slide valve may be open
through to the back for more complete relief of the pressure and the
steam be admitted through the inside of the valve.
The second part of this Invention relates to high-pressure boilers, and
has for its object the obtaining the necessary heating surface in the least
possible cubic space, affording greater facility for cleaning or repairs,
and the obtaining of such a formation of boiler as will enable (by avoid-
ing flat surfaces) the use of stays to be dispensed with to a great extent,
whilst at the same time the strength of the boiler is maintained.
In my improved boilers there is a large increase of fire-box or
radiating heating surface in proportion to that contained in the tubes
leading to the smoke box as compared with the usual practice, especially
in marine boilers. In one arrangement this is attained by making large
fire-boxes with or without vertical tubular stay in each and connected
together by tubes passing through a water space of considerable width.
This water space may be arranged to divide the fire-box horizontally or
angularly instead of vertically with tubes similarly passing thro' it and
a man-hole to give access from the lower to the upper division of
the fire-box. This ensures a great amount of radiating surface, thorough
mixture and combustion of the inflammable gases previous to their
passing through the return tubes to the smoke box. This arrangement

page_text: of boiler may be constructed with either a dry smoke box or with a wet
one as preferred. According to a second form of boiler two furnaces are
employed. leading to one combustion chamber, which is extended as a
return flue underneath, from the upper side of which vertical tubes are
carried between the furnaces to the smoke box. These boilers may be
varied in form from these two plans, which are only intended to illustrate
the special points above referred to.
SPECIFICATION in pursuance of the conditions of the Letters Patent
filed by the said James Henry Bennett in the Great Seal Patent
Office on the 17th September 1869.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
HENRY BENNETT, of Leith, in the County of Mid Lothian, North Britain,
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-nine, in the thirty-
second year of Her reign, did, for Herself, Her heirs and successors
give and grant unto me, the said James Henry Bennett, Her special
license that I, the said James Henry Bennett, my executors, adminis-
trators, and assigns, or such others as I, the said James Henry Bennett,
my executors, administrators, or assigns, should at any time agree with,
and no others, from time to time and 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 AND BOILERS," upon the condition (amongst others) that
I, the said James Henry Bennett, my executors or administrators, by
an instrument 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
immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said James Henry Bennett, do hereby
declare the nature of the said Invention, and in what manner the same

page_text: 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:
My said Invention relates, firstly, to an improved construction of
surface condensers for steam engines.
Secondly. To certain peculiar constructions and arrangements of
frictionless slide valves.
And, thirdly. To certain peculiar constructions and arrangements of
high-pressure steam boilers or generators and their furnaces.
And in order that my 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 Draw-
ings, the same letters of reference indicating corresponding parts in all
the corresponding Figures.
Figure 1 on Sheet 1 of the Drawings represents a vertical section of
an upright surface condenser constructed according to the first part of
my said Invention; and Figure 2 is a full-sized detail sectional elevation
of some of the tubes of the improved condenser.
According to this part of my Invention, which applies to surface
condensers of any form, I make the tubes a at one end fast in a tube
plate b of brass or other metal, whilst their opposite ends (which should
be furthest from the inlet steam pipe c) are secured in a tube plate d of
india-rubber or other elastic material. Each tube is attached separately
to this tube plate and is consequently free to expand or contract of itself
more or less with the others, but independently, thus obviating the
difficulty of keeping the connections tight and in good working order.
It will be seen from reference to Figures 1 and 2 how this arrangement
provides for securing the tubes in the elastic tube plate so as to leave
them entire freedom in expansion and contraction without injury to
themselves or to the tube plate. The ends of the tubes in the elastic
plate are fitted with a nozzle e, screw and nut f, and washer The
other or opposite ends may be slightly enlarged and made fast in the
tube plate by a ferrule or otherwise. The steam is passed through the
tubes, and any deposit formed from tallow can be cleared out without
removal of the tubes. A template may be used inside the india-rubber
tube plate to facilitate the removal or replacing of any of the tubes, and
g.

page_text: doors may be arranged so as to afford facility for cleaning the outsides
of the tubes, or the two tube plates and tubes may be so fitted as to be
withdrawn all together from the condenser for repair or cleaning.
Figure 3 represents a vertical section of a pair of high and low
pressure cylinders provided with combined frictionless slide valves
arranged and constructed in accordance with the second head of my
Invention; Figure 4 is a horizontal section of the same; and Figure 5
is a transversé vertical section and partial end elevation shewing the
arrangement from two opposite points of view.
This part of my Invention consists mainly in the arrangement of two
cylinders, high and low pressure or otherwise, with one valve chest only
common to both cylinders and conducting the steam from the first
cylinder to the second. The steam is passed into the first cylinder from
the inside of the slide valve, then through the valve chest to the second
cylinder, from which it is exhausted through the inside of the second
slide valve and carried to the condenser or atmosphere. The movement
of each valve is independent to the other, and the pressure of steam may
be entirely removed from the slide valves by the interposition of two
loose back plates adjusted by a double-faced wedge and screw to keep
a steam-tight face on both sides of the valves. This adjustment is
assisted by two side bearers which may be used for either one or both
slide valves to prevent the possibility of their being set fast by improper
movement of the double-faced wedge. The setting of the bearers may be
effected from the inside of the chest if preferred, in which case no
possible movement of the double-faced wedge could jam the valves. The
high-pressure steam enters by the pipe A (Figure 4) to the inside of the
slide valve B, from which it is passed alternately above and below the
piston in the high-pressure cylinder C; it passes thence by the outside of
the slide valve B through the valve chest to the low-pressure cylinder D,
and is exhausted from it through the second slide valve E to the con-
denser. The apparatus for maintaining the connection between the
cylinder faces steam-tight where required will be understood by reference
to the Drawings. The double-faced wedge F acts on two back plates
G, H, which are free to move horizontally against their respective
valves B and E, but are confined vertically and at the side by snugs and
fitting strips on the valve chest. Two side bearers 1, I, only are shown
in this instance fitted to the slide valve E of the low-pressure cylinder
and adjustably by screws, the edges of the bearers on the cylinder face

page_text: being slightly tapered. It will be seen in this case that the pressure on
both slide valves is all one way and comes to bear on the two bearers I, I.
Although preferred it is not necessary that either or both the slide valves
should be open through to the back plates, as at some sacrifice of freedom
from friction the valves might be closed at the back and any escape of
steam by these faces prevented.
The essential features of this part of my Invention are, 1 the direct
passage of steam from one of two combined cylinders to the other
and thence to the condenser or atmosphere through one valve chest
only common to both cylinders and to two slide valves working in-
dependently, these being so connected by interposed plates and wedge
surfaces combined with side bearers or not as may be required, that
the pressure of steam or vacuum shall be entirely or partially removed
from the valves, thus reducing the friction of the faces and moving
parts; 2, the peculiar arrangement of parts whereby correctness in
adjusting the steam and other faces is insured without risk of seizing
or setting the valves fast. . This arrangement also admits of the centres
of the cylinders being brought closer together, and allows free access
to the valves or cylinder faces without unneccessary enlargement of the
space between the latter. Separate expansion valves may be used in
connection with these combined valves when desired. A similar ar-
rangement of back plate and wedge may be adapted to single slide valves
for removing the pressure from them.
Figures 6 to 10 inclusive represent various arrangements applicable
to frictionless slide valves for keeping the steam pressure from the
back of the slide valve by means of the valve chest door or cover itself.
This door or cover A may be made circular or of any other convenient
shape with a gland and elastic packing to keep the chest steam-tight,
as shewn at Figure 6. This packing may be used to press the inside
surface of the door A up to the back of the valve B, or it may be used
simply as a steam-tight gland, whilst the valve chest door A is tempered
up to the valve B by other means of adjustment, as illustrated in
Figures 7, 8, and 9, where a central bolt C is used secured to the
cylinder face and passing through the slide valve B and the door A,
or, as shewn in Figure 10, where the central bolt C is outside, supported
by a cross bar or bearer D secured to the valve chest, and through
which the bolt C is screwed and adjusted by a set nut E. An opening
or openings a, a, may be arranged from the space at the
back of the

page_text: slide valve, as shown in Figure 7, mounted with a valve or other
indicator to shew if any pressure exists there to allow the steam to
pass away, and to warn the engineer that adjustment of the door is
required. From the diminished number of bolts in the absence of a
faced joint greater facility is afforded for removing and replacing the
valve chest door when required. As already stated in reference to the
combined valves the slide valve may be open through to the back for
more complete relief of the pressure and the steam be admitted through
the inside of the valve.
The improvements in steam generators which constitute the third
head of my Invention, and which are illustrated on Sheet 2 of my
Drawings, have for their object the obtaining the necessary heating
surface in the least possible cubic space, affording greater facility for
cleaning or repairs, and the obtaining of such a formation of boiler as
will enable (by avoiding flat surfaces) the use of stays to be dispensed
with to a great extent, whilst at the same time the strength of the boiler
is unimpaired.
Figure 1 on Sheet 2 of my Drawings represents a partial end elevation
and transverse section of one form of my improved high-pressure steam
generator; Figure 2 is a longitudinal vertical section of the same taken
along one of the two furnaces; and Figure 3 is a horizontal section of
the boiler also taken along the two furnaces. In this arrangement of
boiler I employ two large fire-boxes or combustion chambers A, A, with
or without a vertical tubular stay B, B, in each and connected together
by horizontal tubes passing through a water space C of considerable
width, say about 12 inches. This water space may be arranged to
divide the fire-box A horizontally or angularly instead of vertically with
tubes similarly passing through it and a man-hole to give access from
the lower to the upper division of the fire-box. This arrangement
insures a great amount of radiating surface and a thorough mixture and
combustion of the inflammable gases previous to their passing through
the return tubes to the smoke box. This boiler may be constructed with
either a dry smoke box or with a wet one as preferred. According to
a second form of boiler illustrated by Figures 4, 5, 6, and 7 (Sheet 2)
two furnaces A, A, are employed leading to one combustion chamber B,
which is extended as a return flue C underneath. From the upper side
of this return flue C vertical tubes D, D, are carried between the
The main feature in both these con-
furnaces to the smoke box E.

page_text: structions of boilers is a large increase of fire-box and radiating heating
surface over and above that contained in the tubes leading to the smoke
box in the usual practise, more especially in marine boilers. These
boilers may be varied in form from the two plans which I have
illustrated, which are only intended to shew the special points above
referred to.
Having now described and particularly ascertained the nature of my
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,-
First. The connecting of one end of the tubes of surface condensers
to an elastic or flexible tube plate, substantially as and for the purpose
herein-before described.
Second. The peculiar construction and arrangement of combined.
frictionless slide valves and the combination of the same with two
cylinders working respectively at high and low pressures, substantially
as and for the purpose herein-before described and illustrated by
Figures 3, 4, and 5 on Sheet 1 of my Drawings.
Third. The application and use of the loose back plates adjusted by
a double-faced wedge and screw for the purpose of maintaining a steam-
tight face on both sides of the slide valves, substantially. as herein-before
described.
Fourth. The establishing of a direct passage of steam from one of two
combined cylinders to the other and thence to the condenser or atmo-
sphere through one valve chest only common to both cylinders and two
slide valves working independently.
Fifth. The preventing the steam pressure from acting upon the back
of a slide valve by the valve chest door itself, arranged and adjusted
substantially as herein-before described and illustrated by Figures 6, 7,
8, 9, and 10 on Sheet 1 of my Drawings.
Sixth. The constructing of steam generators with a fire-box or com-
bustion chamber completely divided by a water space having tubes
passing therethrough in combination with return flue tubes, substantially
as and for the purpose herein-before described and illustrated by Figures
1, 2, and 3 on Sheet 2 of my Drawings.

page_text: Seventh. The constructing of steam generators with two furnaces
in combination with a single combustion chamber extended so as to
form an underneath return flue from which vertical tubes communicate
with a smoke box disposed within the shell of the boiler, substantially
as herein-before described and illustrated by Figures 4, 5, 6, and 7 on
Sheet 2 of my Drawings.
In witness whereof, I, the said James Henry Bennett, have to this
my Specification set my hand and seal, this 14th day of Septem-
ber One thousand eight hundred and sixty-nine.
JA. HENRY BENNETT. (L.S.)