NEW OR IMPROVED APPARATUS FOR EFFECTING INTERMITTENT ACTION OF FOG AND OTHER SIGNALS
Year: 1883

page_text: LETTERS PATENT to Frederick William Durham and James Dixon Churchill
both of N° 23 Leadenhall Street in the City of London for an Invention of
"NEW OR IMPROVED APPARATUS FOR EFFECTING INTERMITTENT ACTION OF
FOG AND OTHER SIGNALS "
PROVISIONAL SPECIFICATION left by the said Frederick William Durham
and James Dixon Churchill at the Office of the Commissioners of Patents on
the 31st December 1883.
FREDERICK WILLIAM DURHAM and JAMES DIXON CHURCHILL both of
N° 23 Leadenhall Street in the City of London, NEW OR IMPROVED
APPARATUS FOR EFFECTING INTERMITTENT ACTION OF FOG AND OTHER SIGNALS
"
It is usual to provide in steam vessels audible fog signals which are sounded
at regular but variable intervals. Our invention relates to means of effecting
automatically the intermittent action of such signals, the apparatus which we
employ for this purpose being so arranged that the interval between successive
signals and the duration of each signal can be varied as desired. For this
purpose, we provide a steam cylinder, the piston of which is directly connected to
the piston of a cataract cylinder. This cataract cylinder is charged with liquid
and has a communication from one end to the other furnished with valves, by
adjusting which, the flow of the liquid in each direction can be regulated. In
communication with the steam cylinder is a second steam cylinder provided with
a piston which is connected to the cock or valve of the whistle, foghorn or other
instrument that produces the audible signal. The first mentioned steam cylinder
is provided with a slide or valve worked by tappets or otherwise, so that at
each end of the stroke of its piston, the admission and emission of the steam are
reversed. The apparatus operates in the following manner. Steam being admitted
to one end of the first cylinder, while its other end is open to discharge, the
piston of the second cylinder is immediately moved by the steam pressure,
opening the cock or valve of the signal, and this remains open during the stroke
of the first piston, the duration of which is determined by the adjustment of
the cataract for the stroke of its piston in the one direction. The first piston

page_text: having completed its stroke, its slide or valve is moved so as to reverse the
supply and discharge, and thus the piston of the second cylinder is caused to
make its back stroke, closing the cock or valve of the signal; and this remains
closed during the back stroke of the first piston, the time of which is determined
by the adjustment of the cataract for the back stroke of its piston. In some cases,
the second steam cylinder may be dispensed with, the signal being connected by a
pipe directly to one end of the first steam cylinder.
According to a modified form of the apparatus, we use one steam cylinder, the
piston of which is connected to the cock or valve of the signal and also to a spring
which acts on the cataract piston, whilst the slide of the steam cylinder is governed
by the motion of the cataract piston. Thus, the cataract piston being at one end
of its stroke, steam acting on the steam piston moves it so as to open the cock or
valve of the signal and at the same time to strain the spring of the cataract
piston. The cataract piston then moves in obedience to the spring with a speed
determined by the adjustment of the cataract flow, and when it completes its stroke,
it reverses the steam supply and discharge, causing the back stroke of the steam
piston followed by that of the cataract piston.
Although we have particularly mentioned the application of the apparatus to
audible signals such as those employed for fog signals, it could obviously be applied
to the working of intermittent signals of other kinds.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Frederick William Durham and James Dixon Churchill in the
Patent Office on the 27th June 1884.
FREDERICK WILLIAM DURHAM and JAMES DIXON CHURCHILL both of
No 23 Leadenhall Street in the City of London "NEW OR IMPROVED
APPARATUS FOR EFFECTING INTERMITTENT ACTION OF FOG AND OTHER SIGNALS
"
It is usual to provide in steam vessels audible fog signals, which are sounded
at regular intervals but variable at pleasure. Our invention relates to means of
effecting automatically the intermittent action of such signals, the apparatus which
we employ for this purpose being so arranged that the interval between successive
signals and the duration of each signal can be varied as desired. We will describe
this apparatus referring to the accompanying drawings, fig. 1 being a sectional plan
of the two steam cylinders, and the cataract cylinder which we employ, and fig. 2
being a side view of the cataract cylinder, with the cover of its valve box removed.
A is a cylinder having a slide B which alternates the admission and emission of
steam at each end of the cylinder, this slide being worked by the steam pressure
in the manner similar to that employed in several kinds of direct acting pumping
engines. The piston of the cylinder A is directly connected with the piston of a
cataract cylinder C which is charged with water, oil, or other suitable liquid.
The two ends of the cataract cylinder C communicate with each other by passages
governed by a valve D and a slit E, the opening of each of which can be regulated
by a screw, so that the strokes of the cataract piston can be timed as desired, the
stroke in either direction being made to occupy a longer or shorter period, according
as the communicating passage is more or less throttled by the adjustment of the
valve and slit.
Each end of a third cylinder & communicates with an end of the cylinder A;
and this cylinder is fitted with a piston, the rod H of which is connected by a cord,
chain or rod to the stop cock or valve that governs the passage to a steam horn or
whistle.
The piston of the cylinder G is preferably provided with buffer springs K
to lessen the shock at each end of its stroke. The action of the apparatus is as
follows: Steam being admitted to the slide case of the cylinder A, and the slide
being, if necessary, shifted towards one end of its stroke by means of a pushing
arm a worked by an external handle, the steam passes to one end of the cylinder A
and also to the corresponding end of the cylinder G causing the piston of the
latter to move rapidly to the one end or the other of its stroke, and so to open or
close the passage to the alarum. While the piston of G is maintained by the
steam pressure at the end of its stroke, the piston of A makes its stroke more or
less slowly, as determined by the resistance offered to the movement of the cataract
piston due to the adjustment of the cataract valves. As the piston of A completes
its stroke, it opens the valve b at the end of the cylinder thus relieving the pressure
on the piston at one end of the slide case, whereupon the slide is shifted and the
pistons of G and A have their movements reversed, the former rapidly and the
latter at the rate, more or less slow, as determined by the adjustment of the cataract
valve which governs the speed of this stroke.
Obviously, by extending the space between the cylinders A and C and providing
suitable tappets on the rod which connects their pistons, the slide B may be worked
by these tappets. Also, the piston rod H, instead of being connected to the cock
or valve of an audible alarm signal might be connected to the screens or colored
glasses of lantern lights, so as to give or alternate visible signals. In cases where
the signal whistle or foghorn is closely adjoining to the apparatus, the cylinder ✪

page_text: may be dispensed with, one end of the cylinder A being put in direct communication
with the sounding instrument which will thus be supplied with steam from the
cylinder A and caused to sound during the stroke of the piston of A in the one
direction and will have no supply (during its backstroke. In cases where the
backward and forward strokes of the cataract piston may be of equal duration,
the adjustable slit E would suffice to regulate that duration. But as it is usually
necessary to give a signal for a very short time and to have a considerable interval
between successive signals we add the valve D to give regulated passage for the
liquid in the one direction in addition to that given by the slit E. When the
cataract piston is making its stroke to the left the valve D closes automatically
and the only passage for the liquid is by the slit E. But when the cataract piston
is making its stroke to the right, the passage consists of that by the slit with the
addition of the opening of the valve D as far as permitted by its adjusting screw.
The left hand stroke being slowly made would thus determine the interval between
successive signals, and the more rapid right hand stroke would determine the
duration of the signal itself.
Having thus described the nature of our invention and in what manner the
same is to be performed, we claim in respect of apparatus for effecting intermittent
action of fog and other signals-
The combination of a steam cylinder A and its automatically moved slide B with
a cataract cylinder C, having the communication for liquid between its ends,
regulated by adjustable valves or their equivalents, substantially as and for the
purposes herein set forth.
In witness whereof, we the said Frederick William Durham and James Dixon
Churchill have hereunto set our hands and seals this twenty third day of June
in the year of our Lord, one thousand, eight hundred and eighty four.
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