IMPROVED MEANS OF AND APPLIANCES FOR RELIEVING GAS RETORTS FROM PRESSURE AND FOR HERMETICALLY SEALING THE JOINTS OF HYDRAULIC MAINS OF GAS WORKS
Year: 1873

page_text: LETTERS PATENT to Alfred Thomas, Manager of the Gas Works,
Alton, in the County of Hants, for the Invention of "IMPROVED
MEANS OF AND APPLIANCES FOR RELIEVING GAS RETORTS FROM PRESSURE AND
FOR HERMETICALLY SEALING THE JOINTS OF HYDRAULIC MAINS OF GAS
WORKS."
Sealed the 3rd June 1873, and dated the 3rd April 1873.
PROVISIONAL SPECIFICATION left by the said Alfred Thomas at the
Office of the Commissioners of Patents, with his Petition, on the
3rd April 1873.
I, ALFRED THOMAS, Manager of the Gas Works, Alton, in the County
of Hants, do hereby declare the nature of the said Invention for "IM-
PROVED MEANS OF AND APPLIANCES FOR RELIEVING GAS RETORTS FROM PRESSURE
AND FOR HERMETICALLY SEALING THE JOINTS OF HYDRAULIC MAINS OF GAS
WORKS," to be as follows:-
This Invention relates to certain means and appliances for relieving
the retort from pressure of gas, and also for sealing hermetically the

page_text: joint to prevent the back flow of gas into the retort when the retort has
to be "drawn."
The Invention consists, in fitting or arranging a cup or vessel in the
lower part of the hydraulic main leading from the retort to the con-
denser. The cup or vessel is internally of larger diameter than the
bottom of the dip pipe, and is capable of being lifted and lowered by
rods or other mechanical appliances from the outside. The bottom
of the dip pipe terminates above the water level to give freedom to
the passage of gas to the condensers at ordinary times, but when the
discharge of the retort has to be done, the cup or vessel is raised above
the level of the bottom and the dip pipe becomes immersed, effectually
and hermetically sealing the pipe against the back flow of gas, the cup
or vessel being full of water or other liquid for the purpose.
According to one method I attach the cup or vessel to a vertical rod,
the upper end of which passes through a stuffing box on the top of the
connection, the termination of the rod being on a rock shaft centred at
the back portion and having a counterpoise to return the cup into the
liquid, when a hand lever which is carried from the front end of the rock
lever down to the cross bar of the screw on the face of the retort is
released after holding the cup in its bottom position. The instant the
lever is removed the counterpoise is permitted to fall and the cup is
thereby raised to seal the joint.
SPECIFICATION in pursuance of the conditions of the Letters Patent, 2
filed by the said Alfred Thomas in the Great Seal Patent Office
on the 3rd October 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALFRED
THOMAS, Manager of the Gas Works, Alton, in the County of Hants,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Third day of April, in the year of
our Lord One thousand cight hundred and seventy-three, in the thirty-
3

page_text: sixth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Alfred Thomas, Her special licence
that I, the said Alfred Thomas, my executors, administrators, and
assigns, or such others as I, the said Alfred Thomas, 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 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 "IMPROVED
MEANS OF AND APPLIANCES FOR RELIEVING GAS RETORTS FROM PRESSURE AND FOR
HERMETICALLY SEALING THE JOINTS OF HYDRAULIC. MAINS OF GAS WORKS," upon
the condition (amongst others) that I, the said Alfred Thomas, 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 immediately
after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Alfred Thomas, 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 thereof, reference being had to the
Drawings hereunto annexed, that is to say :-
The Invention consists of a cup A arranged within the hydraulic main B
between the retorts C and the condenser or exhauster, the cup A being
connected by a vertical rod D to a rock lever E on the outside of the
"H" pipe F, so that by releasing a rod G depending from the rock
lever E the cup A is permitted to rise by the action of a counterpoise H
on the free end of the rock lever E to immerse the bottom end of the
connection therein, the connection forming the passage between the
retort C and the main B. The cup A is charged with tar or other liquid
at first starting, and as the gas is being made fresh portions of tar are
deposited within the two legs J, F, of the "H" pipe, and these fall
or trickle down the connection into the cup A to keep it constantly
full, the overflow being retained in the hydraulic main B by its bason
shaped bottom. The height of the tar in the main B is governed by a
valve L which can be raised and lowered by turning the handle M.

page_text: The Invention further consists in tapering the bottom end of the
connection within the main B as at I, and in making the exterior of
the cup A of the same diameter as the upper part of the connection
which is below the flange N resting upon and bolted to the top plate P
of the main. This connection I is carried up some distance above the
top of the main and has another flange Q to enable it to be bolted to
the flange on the bottom of the leg F of the "H" pipe. The upper end
of the vertical rod D is packed gas tight within the gland R by asbestos,
and its link S permits the free action of the rock lever E upon its pivot
pin at T in the rock movements. The fore end of the lever E is
embraced by a strap guide U and is thereby prevented swinging to one
side when the rod G is thrown to one side by the attendant when he
desires to "draw" the charge of coke from the retort. The lower end
of the rod G is hook shaped to take under the strap V of the retort
cover W, so that on releasing the screw X the attendant must first
release the hook and the counterpoise then causes the vertical rod D
and the cup to rise as in dotted lines and seal the joint effectually and
hermetically against the back pressure of gas from the condenser.
The special arrangement of liquid joints within hydraulic mains of
gasworks is one of the important features of my Invention, because it
not only prevents a back rush of gas at the time of discharging the
coke from the retort and recharging it with coal, but it preserves the
retort from the deposit of carbon which up to this time has, 1., so
seriously affected the proper burning of the charge; 2., diminished the
quantity of gas obtainable from a given quantity of coal; 3., destroyed
the retorts; and, 4., caused an unnecessary quantity of fuel to be
consumed in heating the retorts.
The employment of the liquid joint within the hydraulic main causes,-
1, a less quantity of tar to be formed; and, 2, the tar to be kept in a
liquid state it being so far from positive heat.
I am aware that liquid joints have been and are employed in gasworks
in many ways, but never in the hydraulic main as now patented by me.
I am also aware that attempts have been made by fitting valves in the
pipes to prevent the back rush of gas at the time of the discharge of
the coke from the retort and the recharging of it with coal, but these
have failed chiefly through the tar becoming thick and dried up by the
heat, thereby causing the valves to remain open.

page_text: And having now described the nature of my said Invention and in
what manner the same is to be performed, I declare that I claim,―
Firstly. The employment of a cup within the hydraulic main of gas-
works, such cup being continuously and automatically supplied with
tar and acted upon from the outside as and for the purposes set forth.
Secondly. The special method shown and described by which cups
within hydraulic mains of gasworks can be operated for the purposes set
forth.
Thirdly. Tapering the bottom ends of the connections within hydraulic
mains of gasworks as and for the purposes shown and described.
In witness whereof, I, the said Alfred Thomas, have hereunto set
my hand and scal, this Second day of October One thousand
eight hundred and seventy-three.