Improvements in Steam Jets for Impelling Air or Gas.
Year: 1890

page_text: Date of Application, 2nd Aug., 1890
Complete Specification Left, 1st May, 1891-Accepted, 6th June, 1891
PROVISIONAL SPECIFICATION.
Improvements in Steam Jets for Impelling Air or Gas.
I, JEREMIAH EUGENE MATHEWSON, of Bellefield Works, Sheffield, Engineer,
do hereby declare the nature of this invention to be as follows:-
1
The usual method of applying a steam jet to give velocity to air or gas is to
cause steam of considerable pressure to issue from a hole in the conical end of a
tube so as to drive the air into the small end of another larger conical tube, the
mixed steam and air escaping from its big end. It is found that small steam jets
give better proportionate results than large ones, the probable reason being that
the steam of the outer part of the jet mixes more readily with the air than does
that of the central part, and the smaller the jet the larger is the proportion of the
steam which comes usefully into contact with the air.
My invention consists in making the steam jet act in a radial direction; the steam
is admitted through a tube into the centre of a hollow, flat or lense shaped, circular
disk, and then turns at right angles radially outwards towards the circumference of
the disk, and escapes radially in all directions from the circumference, either
through a number of holes, or through a continuous slit, as in the common steam
whistle. The air to be propelled is admitted on each side of the steam disk, the
apertures being concentric with the disk and of about the same diameter. The air
is sucked in by the steam jet and is driven radially outwards between two circular
flat cheeks placed in the same plane as the steam disk, and which may be either
parallel or flaring.
When the jet is required to produce a pressure of air, the circumferential aperture
between the checks is connected with the pipe which is to convey the impelled air,
and when a partial vacuum is desired the central air apertures are connected with
the vessel which is to be exhausted.
The advantage of the steam whistle form of radial steam disk is, that it becomes
easy to adjust and keep in order a very thin aperture for the escape of the
steam, and thus give a large surface of useful contact between the steam and
the air.
-
When the steam aperture wears and becomes irregular, it can be turned smooth,
and the two sides of the disk can be brought to the proper distance apart.
Dated this First day of August. 1890.
J. E. MATHEWSON.
COMPLETE SPECIFICATION.
Improvements in Steam Jets for Impelling Air or Gas.
I, JEREMIAH EUGENE MATHEWSON, of Bellefield Works, Sheffield, Engineer,
do hereby declare the nature of this invention and in what manner the same is
to be performed, to be. particularly described and ascertained in and by the following
statement :-
The usual method of applying a steam jet to give velocity to air or gas, is to cause
steam of considerable pressure to issue from a hole in the conical end of a tube so
as to drive the air into the small end of another larger conical tube, the mixed steam
and air escaping from its large end. It is found that small steam jets give better
proportionate results than large ones, the probable reason being that the mixture
of the air with the steam takes place at the surface of the conical jet of steam, and
this surface increases only directly as the diameter of the steam aperture is increased,

page_text: t
while the quantity of steam used.will increase.as the area of the steam aperture,
that is, as the square of its diameter.
My invention consists in making the steam jet act in a radial direction; the steam
is admitted through a tube in the centre of a hollow, flat or lens shaped circular
disk and then turns radially outwards, towards the circumference of the disk and
escapes radially in all directions from the circumference either through a number of
holes or through a continuous slit as in the common steam whistle. The air to be
propelled is admitted on each side of the steam disk, the apertures being concentric
with the steam disk. The air is carried in, by the steam jet and, is driven radially
outwards between two circular flat cheeks placed in the same plane as the steam disk
and which may be either parallel or flaring. When the jet is required to produce a
pressure of air, the circumferential aperture between the cheeks is connected with
the pipe which is to convey the impelled air, and when a partial vacuum is required,
the central air apertures are connected with the vessel which is to be exhausted.
The advantage of the steam whistle form of radial steam jet is that it becomes easy
to adjust and keep in order a very thin aperture for the escape of the steam, and
thus give a large surface of useful contact between the steam and the air. When
the steam aperture wears and becomes irregular it can be turned smooth and the
two sides of the disk can be brought to the proper distance apart.
The following is a description of the improved apparatus reference being had to
the drawings.
Fig. 1, is a vertical section.
Fig. 2, is a cross section through the line a b. Fig. 1.
Fig. 3, is a cross section through the line c, d, Fig. 1.
The same numbers indicate the same parts in each figure.
(4) is the tube supplying steam of high pressure; it is closed at one end by the
stuffing box (5) and is open and trumpet mouthed at the other end. (6) is a plug
having a button head (7) at one end; it passes through the tube (4) and is provided
with wings which make a sliding fit in the cylindrical bore of this tube. The other
end of the plug (6) is cylindrical and passes through the stuffing box (5). It has a
screw thread (8) and handle (9) by which it can be moved and set fast in the
tube (4) being kept concentric by the wings (10, 10). The spaces (11, 11) between
the wings give passage to the steam which enters from the side tube (12). The
trumpet mouth of the tube (4) and the lip of the button head (7) are machined so
as to be parallel to each other, and so as to leave between them a thin flat channel
or passage way for the steam, the width of which is adjusted by the screw (8) and
the handle (9). The tube (4) and plug (6) are preferably made of gun metal.
(24) is a globular hollow vessel (preferably of cast iron) having at one end a flat
circular disk or flange (13) and at the other end an opening into which the steam
tube (4) is adjusted and fastened so that its axis. is.perpendicular to the plane surface
of the flange (13) and is concentric with the central opening of the flange (13) and
also with its exterior circumference. By means of the screw (14) and the
jam nut (15) the trumpet mouth of the tube (4) can be adjusted so as to project any
desired small distance beyond the face of the flange (13)." (16) is another globular
hollow vessel having a circular flange (17) similar to (13). On the outside edge of
the flange (13) are three equidistant radial lugs (18; 18) which correspond to similar
lugs on the flange (17). By means of the screw bolts and jam nuts (19) the two
Hanges can be adjusted parallel to each other and at any desired distance. apart, so
as to form a flat radial channel or passage way for the mixed steam and air; the
central plane of which shall coincide with the central plane of the steam channel
left between the mouth of the steam tube (4) and its closing button (7.).
The operation of the apparatus is as follows. Steam of high pressure is admitted
into the tube (4). and issues with velocity as a thin flat radial jet from its mouth,
and carries along with it air on each side, and all around, and, drives it, into the flat
radial channel (20). existing between the two flanges (13,&.17). The air..thus
carried along by the steam jet is supplied through the two tubes (21,.21). and when
a partial vacuum is desired these tubes are connected with the vessel which, is to be

page_text: exhausted and the outside of the passage (20) may be left open or connected with a
chimney. When a pressure of air or gas is desired the tubes (21) are left open for
the entrance of the air and the outside of the passage (20) is connected with the
vessel in which the pressure is to be made. The drawings show the plane of the
escaping jet of steam as being perpendicular to the axis of the central steam
supplying tube, and I prefer this method of construction, but it is evident that the
radial principle can be carried out by deflecting the steam at a less angle than 90°.
For example, by giving the button (7) a conical shape and inserting it in the
mouth of the tube (4) made of a sharper conical shape, a conical and radial jet of
steam can be produced of any desired degree of divergence. In such case the
exterior disks forming the passage way for the mixed steam and air should be made
cones of corresponding angle.
It may sometimes be desirable to cause the impelling steam to issue by a number
of radial holes instead of a continuous radial slit. Such holes may be bored in the
circumference of the steam tube, or they may be formed by radial grooves cut in
the meeting faces (one or both) of the end of the steam tube (4) and its closing
button.
The meeting currents of air drawn in on each side of the steam jet sometimes
cause a disagreeable whistling sound, particularly when the volume of impelled air
is large and of low velocity. This may be prevented by placing thin metal plates
in the position shown by the lines (22, 22) Fig. 1, to guide and divide the currents
of air.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what I
claim is-
1. In a steam jet for impelling air or gas, the combination of a central tube for
admitting the steam with one or more radial apertures for the passage of the steam,
and exterior flanges forming between them a radial passage way into which the air
is impelled in a radial direction.
2. In a steam jet for impelling air or gas, the combination of a radial jet of steam
with the device for adjusting the aperture for the passage of the steam.
3. In a steam jet for impelling air or gas, the combination of a radial jet of
steam with the device for adjusting the aperture for the passage of the mixed steam
and air.
All substantially as described.
Dated this 29th day of April 1891