IMPROVEMENTS IN EJECTORS OR APPARATUS FOR EXHAUSTING FLUIDS, APPLICABLE FOR PRODUCING VACUUM FOR ACTUATING BRAKES AND FOR OTHER PURPOSES."
Year: 1877

page_text: LETTERS PATENT to James Gresham, of the Firm of Gresham and Craven,
of Craven Iron Works, Ordsal Lane, Salford, in the County of Lancaster,
Engineers and Machinists, for the Invention of "IMPROVEMENTS IN EJECTORS
OR APPARATUS FOR EXHAUSTING FLUIDS, APPLICABLE FOR PRODUCING VACUUM
FOR ACTUATING BRAKES AND FOR OTHER PURPOSES."
PROVISIONAL SPECIFICATION left by the said James Gresham at the Office
of the Commissioners of Patents on the 23rd October 1877.
JAMES GRESHAM, of the Firm Gresham and Craven, of Craven Iron Works,
Ordsal Lane, Salford, in the County of Lancaster, Engineers and Machinists. "IM-
PROVEMENTS IN EJECTORS OR APPARATUS FOR EXHAUSTING FLUIDS, APPLICABLE FOR
PRODUCING VACUUM FOR ACTUATING BRAKES, AND FOR OTHER PURPOSES."
My improved exhausting apparatus is intended to be actuated by a jet of steam,
and is designed principally for producing a partial vacuum in a very rapid
manner.
My Invention may be considered as an improvement upon that apparatus for
exhausting for which, amongst other improvements, Letters Patent were granted to
me, numbered 410, and dated the 14th day of February, A.D. 1865, and also as an
improvement upon other Inventions for the like purpose subsequent to the date of
my said Letters Patent.
For so-called vacuum brakes, the important object is to exhaust the air from the
chambers, pipes, and bags or bellows, which are in connection with the brakes, as
perfectly and as near instantaneously as possible, as it is obvious that one or two
seconds of time in the application of the brakes is of the utmost importance in the
case of railways.
The most perfect apparatus acting in duplicate by a jet of steam hitherto used for
producing partial vacuum for vacuum brakes has not been able to produce a
sufficient vacuum for an ordinary train in a sufficiently short period of time, but

page_text: one of my improved ejectors applied to brakes will produce a vacuum equal to
column of about 26 inches of mercury in about half the time of any other j
apparatus hitherto used, even when two are employed.
My Invention consists in an improved combination, arrangement, and constructio
and in the proportions of the parts, which combination and proportions I ha
arrived at after very numerous experiments. The air or fluid to be exhausted
brought by a pipe to a chamber, in which there is a valve seating, and a valve
fitted therein, which valve has four wings (by preference) below the valve_facin
and four above the facing to guide the valve in its lifting movements. The a
chamber has a flange round it, by which it is joined and secured to the stea
chamber, a converging and diverging tube forming a continuation thereof. Betwee
the two flanges a recess is formed to receive and hold the small flange round th
central air tube. The wings of the valve fit into the interior of the entrance of th
central tube, and there is a shoulder formed in it to limit the rise of the valve whe
it opens. The central tube nozzle is coned, and enters some distance from the stea
chamber into the converging cone, which terminates in a parallel part, and the
becomes a diverging cone, which has a screw connection with the pipe, taking awa
the steam and air or other fluid. There is a branch formed on the steam chambe
which is screwed to be coupled with the steam supply pipe.
The annular area of steam between the interior of the diverging cone and the en
of the exterior of the centre of nozzle is about twice the area of the annular are
at the entrance for the steam from the steam chamber to the converging cone, s
that the steam expands from the latter to the former point before coming in in
mediate contact with the air or fluid.
The proportions of the parts which I have so far found the best are given a
follows in whole numbers and decimals, taking the number 1 as the diameter of th
interior of the central nozzle at its discharging end.
The following dimensions are diameters of the parts named below :-
The bore of the entrance pipe to air chamber
Valve
Interior of steam chamber
Interior of central nozzle inlet
Interior of central nozzle outlet
Interior of entrance of the converging tube
Exterior central tube opposite the last-named point
Interior of converging tube opposite the end of central nozzle
Exterior of nozzle at its discharge end
-
The end of the converging cone
-
Parallel part
Small end of diverging cone
Discharging end
Bore of steam supply pipe
The following dimensions are lengths of the parts named :-
Central nozzle
-
Steam chamber
-
Central nozzle extending into converging cone
Converging cone
Parallel part
Diverging cone
0.83
1.30
2.00
1.30
1.00
1.27
1.22
1.23
1.05
1.00
1.00
1.00
1.22
0.62
2:50
1.10
0.70
3.38
0.83
2.55
Two or more of my improved apparatus may be supplied with steam from th
same chamber, so that one may produce vacuum for the engine brakes, and the
other for the carriage brakes independently.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed at
"E
the said James Gresham in the Great Seal Patent Office the 17th April 1878.
JAMES GRESHAM, of the Firm of Gresham and Craven, of Craven Iron Works,
Ordsal Lane, Salford, in the County of Lancaster, Engineers and Machinists.
IMPROVEMENTS IN EJECTORS OR APPARATUS FOR. EXHAUSTING FLUIDS, AP-
PLICABLE FOR PRODUCING VACUUM FOR ACTUATING BRAKES, AND FOR OTHER
PURPOSES."
My improved ejector or exhausting apparatus is upon the steam jet principle,
and is designed principally for producing a partial vacuum in a very rapid
manner.
For so-called vacuum brakes the important object is to exhaust the air from the
chambers, pipes, and bags, or bellows, which are connected with the brakes of the
engines and vehicles of a railway train, as perfectly and as near instantaneously as
possible, as it is obvious that one or two seconds of time in the application of the
brakes on railways is of the utmost importance.
One of my improved single ejectors, applied in connection with the brakes of an
engine and train of the average number of carriages is able to produce a vacuum
equal to about a column of 26 inches of mercury in half the time that the most
perfect steam jet exhausting apparatus hitherto used could produce the same
vacuum, even when two such steam jet exhausters were acting together.
My Invention consists in an improved combination, arrangement, and construction,
and in the proportions of the parts, which combination and proportions I have
arrived at after very numerous experiments.
But before proceeding further with my Invention, it will be most convenient to
refer to the accompanying Drawings, which by Fig. 1, a longitudinal section
represents one of my improved single ejectors; and by Fig. 2, shows one half of the
section on the line A-A, Fig. 1. The air or fluid to be exhausted or propelled is
brought to the instrument by a pipe (a), and is connected by an ordinary screw
coupling (a) with a pipe or chamber (b), in which there is formed a seating for a
valve, and a valve (c) is fitted in such seating with wings (c¹) (four by preference)
below and above the valve facing to guide it in its opening and closing movements.
The air chamber (b) has a flange (6') round it, by which it is joined and secured to
a flange de on the steam chamber (d), a converging tube (d') and diverging tube (d³)
forming a continuation thereof, to the end of which a pipe (d) may be coupled, as
shown, to take away the combined steam and air. Between the two flanges (6¹
and d) a recess is formed to receive and hold the small flange round the central air
tube or nozzle e.
The wings of the valve above its facing fit into the interior of the entrance of the
central tube or nozzle (e), and there is a shoulder formed in it to limit the rise of
the valve when it opens. The central tube nozzle (e) is coned, and enters some
distance fron the steam chamber (d) into the converging cone (d), which
terminates in a parallel part (d²), and then becomes a diverging cone (d³).
There is a branch formed on the steam chamber, which is screwed to be coupled
with the steam supply pipe (d³). The annular area for steam between the interior
of the converging cone (d') at a point opposite to the end of the exterior of the
central nozzle (e) is about twice the area of the annular space at the entrance for
the steam from the steam chamber to the converging cone (d'), so that the steam
expands from the latter to the former point before coming into immediate contact
with the air or fluid.
The proportions of the parts which I have found to be the best are given upon
Fig. 1 in whole numbers, and decimals taking unit, or the number 1 as the
diameter of the interior of the central nozzle (e) at its discharging end.
Fig. 3 is a longitudinal section; and Fig. 4 is a cross section on the peculiar
dotted line A-A, in Fig. 3, showing a double or twin ejector according to my

page_text: Invention. One ejector is intended to be coupled with the brake for the engine
and tender, and the other with the brakes for the carriages, so that in case of
disconnection with the train, the apparatus will act perfectly upon the brakes for
the engine and tender. This twin apparatus consisis of two separate apparatus
similar to the apparatus herein-before described, but with one common steam
chamber (dx), which supplies steam to both nozzles (e):
For applying the brakes to an engine and train by the double ejector to effect
ordinary stoppages, in which it is desirable that the, train should be brought
quickly, but gradually to rest, without jerks or rebounds, I prefer to make cach part
of the double ejector of a capacity proportionate to the work it has to do, and thus for
an average train; the ejector working the brakes for the train should be of larger
capacity than that for the engine and tender, so that both ejectors will do their
work upon the brakes of the engine and train as nearly as possible simultaneously.
I have now particularly described my Invention and the mode of carrying it into
effect, and claim as my Invention,―
Firstly. The improved combination, arrangement, and construction of ejectors;
herein-before described, and illustrated by Figs. 1 and 2 of the Drawings.
Secondly. The combination, arrangement, and construction of double ejectors, as
herein-before described, and illustrated by Figs. 3 and 4 of the Drawings.
In witness whereof,. I, the said James Gresham, have hereunto set my hand
and seal, this Fifteenth day of April, in the year of our Lord One thousand
eight hundred and seventy-eight.