IMPROVEMENTS IN ROTARY GAS EXHAUSTERS
Year: 1869

page_text: LETTERS PATENT to Isaiah Davies, of Harborne, in the County of
Stafford, Mechanical Engineer, for the Invention of "IMPROVEMENTS
IN ROTARY GAS EXHAUSTERS."
Sealed the 1st January 1870, and dated the 3rd August 1869.
PROVISIONAL SPECIFICATION left by the said Isaiah Davies at the
Office of the Commissioners of Patents, with his Petition, on the
3rd August 1869.
I, ISAIAH DAVIES, of Harborne, in the County of Stafford, Mecha-
nical Engineer, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN ROTARY GAS EXHAUSTERS," to be as follows:-
My Invention consists of the combination or arrangement herein-after
described of the parts of rotary gas exhausters, that is to say, apparatus
used for removing or exhausting gas from the gas retorts or generators
and delivering it to the gas holders.

page_text: By making gas exhausters according to my Invention a uniform
delivery of gas is secured, the parts are very simple in construction,
efficient in action, and not liable to derangement.
I construct a rotary gas exhauster according to my Invention in the
following manner:-I arrange two hollow cylinders end to end, their axes
being in the same horizontal line, and between the said cylinders a
partition plate is secured by means of flanges on the abutting cylinders.
Each cylinder is closed by a lid. A rotating piston works in each
cylinder, the said pistons being carried by a horizontal shaft passing
through both cylinders, the partition plate between the cylinders and
the lids being bored for the said shaft to pass through them. Outside
the cylinder lids are stuffing boxes for preventing leakage between the
horizontal shaft and the cylinders. Each rotating piston works between
the partition plate and its respective cylinder lid. The two pistons are
fixed excentrically on the shaft, the part of the piston of greatest radius
working against the inside of the cylinder. The said pistons are not
fixed on the shaft at the same angle, but the part of greatest radius of
the piston in one cylinder is situated opposite the part of least radius of
the piston in the adjacent cylinder, so that when one piston is at its
lowest point of rotation the other piston is at its highest point of rotation.
A packing piece is let into the pistons to prevent the escape of gas
between them and the cylinders. On one side of each cylinder a hori-
zontal nozzle is fixed, in which the outlet port or passage is made.
Sliding in these nozzles are plates constituting stops and valves, the
inner ends of the said plates bearing against the cylindrical surfaces
of the rotating pistons. Each sliding stop works in channels made in
the partition plate and the cylinder lid. These channels as well as the
inner ends of the stops which bear against the pistons are packed to
prevent the escape of gas. These sliding stops when they are at the
end of their. inner stroke divide the space between the piston and
cylinder into two parts or chambers. In each cylinder and on one side
of the stop the inlet port for the gas is made, the said inlet port being
always open, the outlet port or passage for the gas being made in the
nozzle herein-before described, which opens into the cylinder on the
other side of the said stop. By the arrangement described of the
pistons on their shaft the sliding stops and valves are alternately moved
backwards and forwards in their nozzles, and the outlet ports in the said

page_text: nozzles thereby alternately opened and closed. The two sliding stops.
and valves are connected together by rods working through stuffing
boxes in the fronts of the nozzles. The said rods are so coupled together
by means of a lever and links that as the stop in one cylinder is moved
outwards by its piston to close its outlet port the stop in the other
cylinder is pressed inwards against its piston to open its outlet port.
By the revolution of the piston in one cylinder the gas which has been
delivered on one side the stop is driven by the said piston through the
outlet port on the other side the said stop into the open nozzle.
as the piston has driven the gas in front of it from the cylinder and is
about to pass the sliding stop, the outlet port in the nozzle is closed by
the said stop, and the gas which has entered the cylinder on the other
side of the piston and stop is prevented from escaping through the said
outlet port. On the continued rotation of the piston another volume of
'is forced out of the cylinder, and so on. The action described in one
cylinder takes place in the adjacent cylinder, excepting that in conse-
quence of the arrangement of the pistons on their shaft while the outlet
port of one cylinder is open the outlet port of the other cylinder is
closed. A uniform delivery of gas is thereby secured through the
whole revolution of the shaft carrying the two pistons.
gas'
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Isaiah Davies in the Great Seal Patent Office on
the 27th January 1870.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ISAIAH
DAVIES, of Harborne, in the County of Stafford, Mechanical Engineer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Third day of August, 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 me, the said Isaiah Davies, Her special licence that
I, the said Isaiah Davies, my executors, administrators, and assigns, or
such others as I, the said Isaiah Davies, my executors, administrators,
and assigns, should at any time agree with, and no others, from time

page_text: 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 ROTARY GAS EXHAUSTERS,"
upon the condition (amongst others) that I, the said Isaiah Davies,
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 imme-
diately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Isaiah Davies, 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, that is to say :-
My Invention consists of the combination or arrangement herein-after
described of the parts of rotary gas exhausters, that is to say, apparatus
used for removing or exhausting gas from the gas retorts or generators
and delivering it to the gas holders.
By making gas exhausters according to my Invention a uniform
delivery of gas is secured, the parts are very simple in construction,
efficient in action, and not liable to derangement.
I construct a rotary gas exhauster according to my Invention in the
following manner:-I arrange two hollow cylinders end to end, their
axes being in the same horizontal line, and between the said cylinders a
partition plate is secured by means of flanges on the abutting cylinders.
Each cylinder is closed by a lid. A rotating piston works in each
cylinder, the said pistons being carried by a horizontal shaft passing
through both cylinders, the partition plate between the cylinders and the
lids being bored for the said shaft to pass through them. Outside the
cylinder lids are stuffing boxes for preventing leakage between the
horizontal shaft and the cylinders. Each rotating piston works between
the partition plate and its respective cylinder lid. The two pistons are
fixed excentrically on the shaft, the part of the piston of greatest radius
working against the inside of the cylinder. The said pistons are not
fixed on the shaft at the same angle, but the part of greatest radius of
the piston of one cylinder is situated opposite the part of least radius of

page_text: the piston in the adjacent cylinder, so that when one piston is at its
lowest point of rotation the other piston is at its highest point of rotation.
A packing piece is let into the pistons to prevent the escape of gas
between them and the cylinders. On one side of each cylinder a hori-
zontal nozzle is fixed, in which the outlet port or passage is made;
sliding in these nozzles are plates constituting stops and valves, the
inner ends of the said plates bearing against the cylindrical surfaces of
the rotating pistons. Each sliding stop works in channels made in the
partition plate and the cylinder lid. These channels are cut truly in
the said parts in the same plane as the face of the nozzles, and thereby
form a perfect bearing for the stops to work upon and prevent the escape
of gas. These sliding stops, when they are at the end of their inner
stroke, divide the space between the piston and cylinder into two parts
or chambers. In each cylinder, and on one side of the stop, the inlet
port for the gas is made, the said inlet port being always open, the outlet
port or passage for the gas being made in the nozzle herein-before
described, which opens into the cylinder on the other side of the said
stop. By the arrangement described of the pistons on their shaft the.
sliding stops and valves are alternately moved backwards and forwards in
their nozzles, and the outlet ports in the said nozzles thereby alternately
opened and closed. The two sliding stops and valves are connected
together by rods working through stuffing boxes in the fronts of the
nozzles. The said rods are so coupled together by means of a lever and
links that as the stop in one cylinder is moved outwards by its piston to
close its outlet port the stop in the other cylinder is pressed inwards
against its piston to open its outlet port. By the revolution of the piston
in one cylinder the gas which has been delivered on one side the stop is
driven by the said piston through the outlet port on the other side the
said stop into the open nozzle. As soon as the piston has driven the gas
in front of it from the cylinder, and is about to pass the sliding stop, the
outlet port in the nozzle is closed by the said stop, and the gas which
has entered the cylinder on the other side of the piston and stop is
prevented from escaping through the said outlet port. On the continued
rotation of the piston another volume of gas is forced out of the cylinder,.
and so on. The action described in one cylinder takes place in the
adjacent cylinder, excepting that in consequence of the arrangement of
the pistons on their shaft while the outlet port of one cylinder is open
the outlet port of the other cylinder is closed. A uniform delivery of

page_text: gas is thereby secured through the whole revolution of the shaft carrying
the two pistons.
Having explained the nature of my Invention, I will proceed to
describe, with reference to the accompanying Drawings, the manner in
which the same is to be performed.
Figure 1 represents in front elevation a rotary gas exhauster
constructed according to my Invention; Figure 2 is a side elevation of
the same; Figure 3 is a plan of the same; and Figure 4 is a transverse
vertical section of the same taken through the line a, a, Figure 1;
Figure 5 is a horizontal section of the hollow cylinders, pistons, and
valves and stops of the gas exhauster drawn to a larger scale; and
Figure 6 is a vertical transverse section of the same taken through the
axis of the cylinders. The same letters of reference are employed to
indicate the same parts in the several Figures of the Drawings.
b, c, are the two hollow cylinders, placed end to end, their axes being
in the same horizontal line. The said cylinders are supported on the
bed or foundation d. e is the partition plate between the cylinders,
secured at its reduced edge by the flanges on the abutting cylinders, as
best seen in Figures 5 and 6. The cylinder 6 is closed by the lid b², and
the cylinder c is closed by the lid c². fis a horizontal shaft passing
through both the cylinders b, c, and the partition plate e. The said shaft
is supported by standards g, g, and is provided with a fast and loose
pulley. By means of a band passing over the fast pulley a rotary motion
may be given to the said shaft. The shaft may however be driven by
other gearing. The said shaft f carries the rotating pistons h, i, working
respectively in the cylinders b, c. The lids b, c, of the cylinders are
furnished with stuffing boxes bs, cs, through which the shaft fpasses.
The escape of gas between the shaft and cylinders is thereby prevented.
Each of the pistons h, i, works between the partition plate e and its
respective cylinder lid, the cylindrical faces of the pistons bearing
against the inside of the cylinders (see Figure 5). The pistons h, i, are
fixed excentrically on the shaft f, the part of greatest radius of the
piston in one cylinder being situated on the shaft opposite the part of
least radius of the piston in the adjacent cylinder, as will be understood
by an examination of Figure 5. By this arrangement of the two pistons
one piston is at the end of its advance stroke when the other piston is at
the end of its back stroke. The faces of the pistons are packed with a

page_text: metallic packing in the ordinary way to prevent the escape of gas
between them and the cylinders. At the front of each of the cylinders
is a horizontal nozzle k, l, in which the sliding stops and valves m, n,
work, the inner ends of the said stops and valves bearing against the
cylindrical surface of the rotating pistons h, i. The plates m, n, con-
stitute valves when they close the ports herein-after described, and stops
when they divide each cylinder into two parts or chambers. The outer
ends of the stops and valves m, n, take a close bearing on the bottoms
of the nozzles k, l, and their inner ends work in channels m², n², made in
the partition plate e and lids 62, c³, (see Figure 5). The channels m³, n²,
are cut truly in the partition plate and lids in the same plane as the face
of the nozzles k, l, and thereby form a perfect bearing for the stops and
valves m, n, to work upon, and prevent the escape of gas. When these
sliding valves and stops are pushed inwards in the manner herein-after
explained they divide the space between each of the pistons and
cylinders into two equal parts or chambers. In Figures 4 and 5 the
valve and stop n is represented dividing the space between the piston i
and cylinder c into two equal parts or chambers. p, q, are the inlet ports
for the gas, which are always open. These ports p, q, are in com-
munication with the gas retorts. r, 8, are the outlet ports at the ends of
the nozzles k, l. The said outlet ports are in communication with the
gas holder. The outlet ports r, 8, open into the nozzles by the cross
passages, 8, (see Figure 5) in the bottoms of the nozzles. The outlet
ports of the nozzles open into the cylinders b, c, by the passages t, t, at
the inner ends of the nozzles over the stops and valves m, n, and the
inlet ports p, q, open into the cylinders b, c, by the passages u, u, under
the said stops and valves. A front elevation of the passages't, t, and
u, u, is represented in Figure 6. When the sliding valves and stops m, n,
begin to make their inner stroke they uncover the passages ³, 8³, and
open the outlet ports r, 8; and when the said valves and stops are near
the end of their outer stroke they cover the said passages, 8, and close
the said outlet ports. The sliding stops and valves are furnished with
rods v, w, working through stuffing boxes k², P, in the fronts of the
nozzles k, l, the said rods being coupled together by the links v³, w³, and
lever x, the said lever turning on the centre y carried by the bracket z
affixed to the nozzles k, l. The inner ends of the rods v, w, are
connected to the stops and valves m, n, by the crutch joints represented
in Figure 5.
"

page_text: By an examination of the Drawing it will be seen that as the
pistons h, i, rotate in the cylinders b, c, they alternately act upon the
sliding stops and valves m, n, and cause them to be alternately moved
backwards and forwards in their nozzles k, l, and alternately to open and
close the outlet ports r, s, the coupling parts ², a, and w³ of the stops
and valves causing the stop or valve which is being moved outward by
the piston for closing its outlet port to press inwards the other stop and
valve for opening its outlet port and keeping it to its bearing against
the piston (sce Figures 3 and 5).
When the gas exhauster is in action the two pistons h, i, by their
rotation in the cylinders b, c, draw gas into the said cylinders by the
ports p, q, below the stops, and force gas from the cylinders by the
ports r, s, above the stops, that is to say, the parts of the gas exhauster
being in the respective positions represented in Figure 4, the gas which
has been delivered above the piston i and stop n of the cylinder c is
being forced by the said piston through the passage t and nozzle / into
the outlet port 8, which has been opened by the valve gas at the same
time entering below the stop n and piston i through the outlet port q,
and filling up the space in the cylinder below the stop. The action of
the piston and stop m in the cylinder b is the same as that of the
corresponding parts in the cylinder c, excepting that from the different
positions of the pistons on the shaft f when one piston is at the end of
its advance stroke the other piston is at the end of its back stroke. A
continuous and uniform delivery of gas is thus secured through the
whole revolution of the shaft, the valves and stops m, n, being alter-
nately moved backwards and forwards by the operation of the pistons
and coupling gear, and the outlet ports thus alternately opened and
closed, as herein-before described.
Although I prefer the arrangement represented of coupling the two
valves and stops together so that the advance of one shall cause the
retiring of the other, yet the lever x may be placed inside the nozzles
and connected to the valves and stops by links; or the said valves and
stops may be disconnected from each other and their return or back
motion be effected by means of springs or weights, the said springs or
weights keeping the valves and stops in close contact with the
cylindrical surface of the pistons.
Instead of placing the nozzles and valves and stops horizontally, as

page_text: represented, they may be placed vertically on the top side of the
cylinders. .In this case the valves and stops have a vertical sliding
motion, and a spring or weight may be employed to assist in giving
them their back motion.
Instead of employing two hollow cylinders and two revolving pistons
combined with two sliding valves and stops, as described and illustrated
in the accompanying Drawings, one cylinder, revolving piston, and
horizontal sliding valve and stop may be employed. In this arrange-
ment I effect the return or back motion of the single sliding stop or
valve into the cylinder after the revolving piston has passed it by means
of a spring or weight, or by an excentric on the revolving shaft f.
When an excentric is employed it is situated on the shaft outside the.
cylinder lid, a rod from the said excentric being connected with a lever,
and the latter with the sliding stop and valve in front of the nozzle.
The shaft is provided with a fly wheel.
Although my Invention is particularly applicable for exhausting
illuminating gas from retorts in which it is made, yet my Invention
is also applicable for exhausting or forcing other gases for various
purposes.
Having now described the nature of my Invention, and the manner in
which the same is to be performed, I wish it to be understood that I do
not limit myself to the precise details herein described and illustrated, as
the same may be varied without departing from the nature of my
Invention; but I claim as my Invention of improvements in rotary gas
exhausters,-
Firstly. The combination of two hollow cylinders and revolving
pistons working therein, the said revolving pistons being arranged on
their shaft and operating substantially as hercin-before described and
represented in the accompanying Drawings, whereby a continuous and
uniform delivery of gas is obtained through the whole revolution of the
shaft carrying the said revolving pistons.
Secondly. The combination with the said hollow cylinders and pistons
of two sliding valves and stops, whether coupled or uncoupled, for
alternately opening and closing the outlet ports of the gas exhauster, and
also for bearing against the pistons and dividing the cylinders of the said
gas exhauster, substantially as herein before described and represented
in the accompanying Drawings.

page_text: Thirdly. The combination of a single hollow cylinder, revolving
excentric piston, and sliding valve and stop, substantially as described,
for obtaining an intermittent delivery of gas from the gas exhauster.
In witness whereof, I, the said Isaiah Davies, have hereunto set
my hand and seal, this Twenty-fifth day of January, in the year
of our Lord One thousand eight hundred and seventy.
Witness,
RICHARD SKERRETT,
Clerk to George Shaw,
Birmingham.
ISAIAH DAVIES. (L.S.)