IMPROVEMENTS IN CENTRE VALVES EMPLOYED IN CONNECTION WITH GAS PURIFIERS
Year: 1882

page_text: LETTERS PATENT to Robert Dempster Junior of the firm of Robert Dempster
and Sons of Elland in the County of York Gas Engineers for an Invention
of "IMPROVEMENTS IN CENTRE VALVES EMPLOYED IN CONNECTION WITH GAS
COMPLETE SPECIFICATION filed by the said Robert Dempster, junior, at
the Office of the Commissioners of Patents on the 22nd November 1882.
ROBERT DEMPSTER, Junior of the firm of Robert Dempster and Sons of Elland
in the County of York, Gas Engineer "IMPROVEMENTS IN CENTRE VALVES.
EMPLOYED IN CONNECTION WITH GAS PURIFIERS "
My Invention relates to what are known as centre valves, employed in apparatus
used in the purification of gas.
It is well understood, these valves are generally used in connection with four
purifiers, three of them always being open to the valve and the other one closed,
so that the lime or oxide of iron contained therein can be changed; but, when the
lime or oxide in the next succeeding purifier becomes impure and is no longer able
to remove sulphuretted hydrogen from the gas, the valve cover is turned partially
around on its seating, shutting off the most impure purifier, and putting in action.
the one which was previously at rest, so that the lime in the impure one can be
changed, and so on, one after another, but always so arranged, that one of the
purifiers remains idle.
The object of my Invention is to construct these centre valves so that all the
purifiers, whatever be the number employed, may be in operation at one time,
which I accomplish by a modified form of valve and in the arrangement of
mechanism for operating it.
My Improvements therein consists in forming two additional openings which
are covered by a moveable slide, somewhat after the manner of a high pressure
steam engine valve. This slide valve cover is moved on its seating by means of
an arm extending from a long boss or hollow shaft, working upon the central
shaft of the valve. It is moved in either direction by a lever, keyed or otherwise
fixed on the top of the said boss. When this slide valve is moved in either
Price 1

page_text: direction it is kept in its place by means of a spring catch working in suitable
slots or not bes formed in the indicator wheel. Instead of the slide valve being
moved by an arm from the hollow shaft it may have a boss formed thereon and
made secure onto the hollow shaft and turned around thereby. The main body
of the valve is actuated in the usual manner by a pinion working in a rack formed
around the body of the circular valve, or it may be actuated by means of a pinion
and wheel attached to the central shaft.
Such being the nature of my Invention, I will now proceed to describe the same,
and in order that the Invention may be better understood, I herein give reference
to the accompanying sheets of Drawings wherein Fig 1 is elevation and Fig 2
section of a centre valve shewing the application of my Invention-1-is the usual
syphon pan, the gas entering therein at 2 as shewn by the arrow. The gas thence
passes up through the centre of the body of the valve at 3 and into the inlet
thereof. It then passes through the outlet 4 (see Fig 3) into the first purifier,
returning therefrom back into the valve through the inlet 5. It thence passes in
like manner through 6 and back again at 7 and again through 8 and back at 9
whence it makes its exit if only three purifiers are required to be at work at one
time, but when the fourth purifier is required to be in operation, it passes into the
slide valve cover 10 which directs the gas down and through one of the additional
openings 11 through the outlet 13 into the fourth purifier and ultimately makes
its exit through the opening 14 to the outlet 15.
When any one of the purifiers required to be changed, the main valve is moved
on its seating by a lever or other instrument placed on the upright shaft 16
operating the pinion 17 in gear with the rack 18 formed around the body of the
valve by which it is moved on its seating. The valve 10 is moved on its seating
so as to direct the way of the gas either into three or four purifiers, and this is
done by covering one or other of the additional openings 11 and 12 shewn more
clearly in plan views Figs 3 and 4 these two Figures shewing the said valve. 10 in
two different positions This valve is moved backward and forward by means of
hand lever 19 fixed on the top of the hollow shaft 20 working upon the centre
shaft of the valve 21, which by the employment of the two stuffing boxes 22
As the valve 10
and 23 can be operated independantly of the said centre shaft.
is concealed under the circular cover 24, its position and the extent of its movement
from one opening to another is determined by means of the spring catch 25
working in a circular groove formed in the indicator wheel 26. This groove has
two notches formed in it as shewn in plan Fig 5 into which the spring catch 25
enters, thereby determining the extent of movement required to be given thereto
and at the same time holding it in position.
Instead of employing the groove and spring catch for this purpose, a segment 27
may be used (see Fig 6 which is elevation and Fig 7 plan) in gear with a pinion 28
working upon a stud 29 secured to the indicator wheel 26, the valve 10 is also
extended and secured to the long boss or hollow shaft by which it is operated
as shewn in Figs 6 and 8 instead of operating it by the arm 30 shewn in Figs 2,
3 and 4
Fig 9 is plan of the main valve seating and Fig 10 is underneath plan of the
cover, working on the top of the said valve seating the various openings for the
passage of gas.
In order to insure that the valve cover 10 may be moved the required distance
and effectually prevent its moving from the position in which it is placed, a bell
crank lever 31 is employed weighted at one end 32, the lower end of which takes
into notches formed in the annular ring 33 which holds it in proper position until
it is required to be moved again.
Fig 11 is a diagram of the centre valve, shewing the ports open and the valve
cover 10 in the position it occupies when four purifiers are at work, and Fig 12 is
another diagram shewing the ports open and position of the valve cover when only
three purifiers are at work.
Although I shew in the Drawings the application of my Invention to a centre

page_text: valve connected with four and three purifiers, I would have it understood that it
can be adopted and arranged so that two or one only may be in action at once
which is easily done by forming the notches in the indicator wheel 26 at suitable
distances apart, also that the flow of gas may be reversed if required.
Having now described the nature of of this Invention, and the manner in which
the same is to be performed, I wish it to be understood that I do not confine
myself to the precise details herein-before described and illustrated in the accom-
panying Drawings, as the same may be varied without departing from the nature
of the said Invention but I claim―
Firstly. The use and employment of the additional openings 12 and 18 for
the purpose of connecting the centre valve with the fourth purifier, substantially
as described.
Secondly The use and employment of the slide valve cover 10 for the purpose
substantially as herein shewn and described.
Thirdly. The employment of the hollow shaft 20 with stuffing boxes 22 and 23
substantially as herein shewn and described.
Fourthly. The means herein shewn and described for operating the said slide
valve cover substantially as herein shewn and described.
In witness whereof, I the said Robert Dempster Junior have hereunto set
my hand and seal this twentieth day of November in the year of our Lord,
one thousand eight hundred and eighty two.
Witness
A B CROSSLEY
Tasker & Crossley
Patent Agents
Halifax.
WUDENT DELISTEN ON (140)