MENTS IN EJECTORS FOR EXHAUSTING AIR."
Year: 1876

page_text: PROVISIONAL SPECIFICATION left by John Y. Smith at the Office of the
Commissioners of Patents on the 13th April 1876.
JOHN Y. SMITH, of Pittsburg, Pennsylvania, United States of America, but now
"IMPROVE-
residing at 85, Lancaster Road, in the County of Middlesex, Engineer.
MENTS IN EJECTORS FOR EXHAUSTING AIR."
My Invention relates to an improved form of ejector which is chiefly designed to
facilitate the working of the continuous vacuum brake described in the Specifica-
tions of former Letters Patent dated the 23rd January 1873, Nod. 279; the 28th of
August 1874, Nod. 2950; the 9th day of March 1875, Nod. 875; and the 6th day of
September 1875, Nod. 3125.
I have from time to time in connection with the aforesaid vacuum brake
apparatus used ejectors of various forms, and in the course of my experiments in
connection with such vacuum brake apparatus I have discovered that the most
perfect vacuum is obtained by using an ejector constructed as to the body thereof
substantially in the manner shewn in the Specification of the last-mentioned former
Letters Patent, but having the nozzle of the air eduction pipe and that portion of
the outer frame of the steam chamber of the ejector immediately surrounding the
nozzle, and beyond the outer extremity thereof, constructed in the proportions and
with the angles herein-after mentioned, a nozzle of two inches internal diameter at
the outlet being taken as an example. The nozzle is constructed with the exterior
of that portion of the sides thereof which forms the nozzle proper converging
towards the outlet of the ejector at such an inclination that lines drawn correspond-
ing to the two sectional sides and continued in a straight line will cross or intersect
at a point exactly 8 inches from the end of the nozzle. The interior sides or walls
of the steam chainber of the ejector are constructed at the portion immediately
opposite the nozzle in the following manner :-Taking one sectional side as an
example with which the opposite side corresponds the side is constructed of two
portions or lengths of a 'different inclination which converge and form an angle of
174° at a point exactly 5/8ths of an inch from the outer end of the nozzle measured
from the extremity thereof inwards a space of 1/16th of an inch is left between the
angle formed by the said converging portions and the opposite point of the external
side of the nozzle, which space being continued all round forms an annular orifice
for the passage of the steam. That converging portion of the sectional side which
is situate on the side of the angle towards the outlet of the ejector is continued for
a distance of 4 inches, and at its termination it joins at an angle of 176° „, 30′
another length, forming a line nearly paralel with a line drawn through the centre
CD71

page_text: of the nozzle, and which additional length is continued to the requisite distance to
form the outlet of the ejector. The other converging portion of the sectional side
at the part where the nozzle is situate is continued for a distance of 5/8ths of an incli
from the angle in the opposite direction, beyond which point it may be enlarged
and form any desired contour. By this means I obtain a more perfect vacuum
than has previously been attainable by means of a steam ejector. For the purpose
of obtaining increased power when required I combine two ejectors constructed in
the form above mentioned substantially in the manner described in the Specification
of the said former Letters Patent, No. 29507*.