IMPROVEMENTS IN AIR INJECTING NOZZLES FOR VENTILATING AND OTHER PURPOSES
Year: 1879

page_text: This Specification was, upon the 27th day of January, 1888, amended under
Sections 18 to 21 of the Patents, Designs, and Trade Marks Act, 1883.
The Amendments are shown in sweed and italic tune I
LETTERS PATENT to Alexander Melville Clark, of. 53, Chancery Lane, in the
County of Middlesex, Patent Agent, for the Invention of "IMPROVEMENTS
IN AIR INJECTING NOZZLES FOR VENTILATING AND OTHER PURPOSES." A
communication from abroad by David Culver Green, of Brooklyn, King's
County, State of New York, United States of America.
aled the 30th April 1880, and dated the 6th November 18
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark at
the Office of the Commissioners of Patents on the 6th November 1879.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of
Middlesex, Patent Agent. "IMPROVEMENTS IN AIR INJECTING NOZZLES FOR
VENTILATING AND OTHER PURPOSES." [A communication from abroad by David
Culver Green, of Brooklyn, King's County, State of New York, United States of
America.]
This Invention relates to apparatus for producing blasts or currents of air for
ventilation or other purposes by the injective action of jets of steam or compressed
air discharged from nozzles into suction throats or tubes, through which a largo
volume of air is thus caused to flow by the inducing action of the jet, and the
Invention is embodied mainly in an improved form of injection nozzle or jet
whereby the velocity and pressure of the jet is maintained independent of
variations in the volume supplied to it from the compressing pump or other
apparatus, thus greatly increasing the effectiveness of the jet, and causing its
effectiveness to at all times correspond proportionately with the volume supplied,
as hereinafter fully set forth.
In producing air currents or blasts by the injective or inducing action of jets,
it is necessary, as is well known, that the jet be discharged under a positive
pressure and at a high velocity in order to obtain an effective inducing action.
The pressure of course mainly determines the velocity of the jet, and it is found
that the best effect is obtained with a jet of a certain pressure and velocity, which
of course varies in different cases; but when this point is determined in each case
it cannot be much departed from without serious loss.
The volume of the jet is of course another element in its effectiveness, but if its
pressure and velocity be maintained its effectiveness will be also maintained, and

page_text: will correspond with its increase or decrease of volume, while if its power and
velocity be allowed to fall or vary much from the best determined point, the
increase in volume will give no corresponding effectiveness, but will be mainly
a loss of power. Hence the main defects in air jet nozzles as heretofore con-
structed, and which I am to overcome, is that they are formed with a discharge
aperture of a fixed and uniform area, so that to maintain the pressure and velocity
of the jet up to its point of greatest efficiency it is necessary that the compressing
pump or other source of supply form a constant volume corresponding to sucli
pressure and velocity from a jet of that area, and if the volume increase or decrease
beyond this point the area of the jet then of course becomes proportionately too
small or too large, hence causing the pressure and velocity of the jet to corre-
spondingly decrease or increase, and thus rendering its action inefficient.
Now the main feature of the present Invention may be stated to consist in
constructing the air jet nozzle with an automatic valve arranged to govern its
discharge aperture and loaded to open at a certain pressure, so that hence the jet
is discharged uniformly at this pressure, and should the supply to the jet decrease
in volume the valve will partly close to correspondingly reduce the area of the
discharge aperture, and thus maintain the uniform pressure and velocity of the
jet, and should the volume increase the valve will open wider, thus discharging
a jet of greater volume yet at practically the same pressure, thus maintaining the
efficiency of the jet under a varying supply, causing the volume of the induced
current to increase proportionately as the volume of the inducing jet increases.
The valve consists of a plug which is arranged in the aperture of the nozzle and
of the injector, and when quiescent fully closes said aperture, preventing any
discharge from the nozzle. The outer extremity of the valve plug is preferably
of an elongated tapering formn; its middle, or that part which fills and closes the
aperture of the nozzle, is cylindrical to form a close fit for the nozzle aperture,
while its inner part is also tapering to form, as the valve is pressed out of the
nozzle, an annular outlet which increases in area in proportion to the distance it is
pressed out, as will be readily understood. From this inner tapering part of the
valve plug project short radial ribs, but which extend only to the same diameter
as the cylindrical or plain part of the valve, thus forming grooves between each
other through which the air escapes, while the ribs serve to guide tho plug
centrally in the nozzle aperture. The stem of the valve is provided either with
adjustable weights or a strong spring which constantly tends to keep the plug
drawn in and thus close the nozzle aperture, and which may be adjusted so as to
place any desired pressure on the valve, so that the jet will be discharged from
the nozzle at this pressure only. Where the jet is so arranged as to discharge
upwardly weights may be used to load the stem instead of a spring, but for all
other situations I prefer to use a strong spring of such length that its tension will
not vary much with a slight compression or extension thercof. The spring may be
adjusted to place the required pressure on the valve by means of adjusting and
jam nuts on the stem, as will be readily understood, and the spring and stem may
be enclosed in an air tight tube projecting from the neck of the valve casing, thus
enabling the packing of the stem to be dispensed with, and therefore securing a
more sensitive action of the valve; but if desired the enclosing tube may be
omitted and the stem passed through a gland in the neck of the valve casing,
leaving the spring and stem exposed.
The nozzle is connected to the air supply pipe preferably by a branch or
coupling on the side of the casing, and for ordinary ventilating purposes the air
is supplied to the nozzle under a pressure of about 5 lbs. to the square inch.
For ventilating purposes an air compressing pump would be employed drawing the
air from the apartment or other place to be ventilated, or from the external
atmosphere, and discharging the compressed air through a pipe terminating with
several of the improved nozzles arranged in ventilating passages leading into and
out of the apartment. These nozzles are arranged to discharge into contracted
suction throats, through which a large volume of atmospheric air is thus induced

page_text: to flow into and out of the apartment by the injecting action of the jet, as will be
readily understood, and these throats are preferably made adjustable towards the
nozzle so as to obtain the best relative position thereof. If the valves of the
injector nozzles be now set to the regular pressure and the air pump put in motion
the nozzle valves will confine the air till it attains the desired pressure, when the
valve will open allowing the discharge of an energetic jet from the nozzle having
the required velocity and pressure to produce an effective inducing action, and thus
cause a strong induced current to flow through the suction throats with the
inducing jet. Should however the speed of the pump decrease rendering the
supply to the nozzle less, or should it increase rendering the supply greater,
the nozzle valve will partly close or open correspondingly, thus causing the volume
of the jet to always correspond to the volume of its supply, while its pressure and
velocity are maintained practically uniform, thus causing the jet to act to its
greatest efficiency under the different variations in volume, and producing under
different volumes a corresponding and full efficiency. By means of these auto-
matically acting nozzles it is found that the volume of the inducing jet being one
the volume of the induced current will be thirty five, thus practically obtaining
from one pump the capacity of thirty five pumps. The improved nozzle may of
course be used for producing air blasts or currents for other purposes than ven-
tilation, and it will also be understood that in some cases the nozzle may be
supplied with live steam instead of compressed air, but the use of the latter is more
generally contemplated. I sometimes prefer to construct the valve plug of the
nozzle so as to discharge a central jet as well as an annular one, the centre of
the plug in this case being provided with a bɔre arranged to embrace and slide
over a tapering plug fixed in the centre of the nozzle, but this is optional.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Alexander Melville Clark in the Great Seal Patent Office on the 6th
May 1880.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of
Middlesex, Patent Agent. "IMPROVEMENTS IN AIR INJECTING NOZZLES FOR
VENTILATING AND OTHER PURPOSES." A communication from abroad by David
Culver Green, of Brooklyn, King's County, State of New York, United States of
America.
This Invention relates to apparatus for producing blasts or currents of air for
ventilation or other purposes by the injective action of jets of steam-or compressed
air discharged from nozzles into sucton throats or tubes, through which a large
volume of air is thus caused to flow by the inducing action of the jet, and the
Invention is embodied mainly in an improved form of injection nozzle or jet
whereby the velocity and pressure of the jet is maintained independent of varia-
tions in the volume supplied to it from the compressing pump or other apparatus,
thus greatly increasing the effectiveness of the jet and causing its effectiveness to
at all times correspond proportionately with the volume supplied, as hereinafter
fully set forth.
In producing air currents or blasts by the injective or inducing action of jets it is
necessary, as is well known, that the jet be discharged under a positive pressure
and at a high velocity in order to obtain an effective inducing action. The
pressure of course mainly determines the velocity of the jet, and it is found that
the best effect is obtained with a jet of a certain pressure and velocity which varies
in different cases, but when this point is determined in each case it cannot be much
departed from without serious loss. The volume of the jet is of course another
element in its effectiveness, but if its pressure and velocity be maintained its
effectiveness will be also maintained and will correspond with its increase or
decrease of volume, while if its power and velocity be allowed to fall or vary much
from the best determined point the increase in volume will give no corresponding
effectiveness but will be mainly a loss of power. Hence the main defects in air
jet nozzles as heretofore constructed, and which I am to overcome, is that they are
formed with a discharge aperture of a fixed and uniform area, so that to maintain
the pressure and velocity of the jet up to its point of greatest efficiency it is
necessary that the compressing pump or other source of supply form a constant
volume corresponding to such pressure and velocity from a jet of that area, and if
the volume increase or decrease beyond this point the area of the jot then of course
becomes proportionately too small or too large, hence causing the pressure and
velocity of the jet to correspondingly decrease or increase, and thus rendering its
action inefficient.
Now the main feature of the present Invention may be stated to consist in
constructing the air jet nozzle with an automatic valve arranged to govern its
discharge aperture, and loaded to open at a certain pressure, so that hence the jet
is discharged uniformly at this pressure, and should the supply to the jet decrease
in volume the valve will partly close to correspondingly reduce the area of the
discharge aperture, and thus maintain the uniform pressure and velocity of the jet,
and should the volume increase the valve will open wider, thus discharging a jet of
greater volume, yet at practically the same pressure, thus maintaining the
efficiency of the jet under a varying supply, causing the volume of the induced
current to increase proportionately as the volume of the inducing jet increases.
Figure 1 in the accompanying Drawings is a longitudinal section of the improved
air injector nozzle, and Figure 2 a cross section of its valve plug on line x, x.
Figure 3 represents a ventilating apparatus provided with the improved nozzles.
In Figure 1 A indicates the casing or body of the improved injector valve or

page_text: nozzle, and the nozzle end thereof, in the aperture of which, as illustrated. is
arranged a valve plug B, which when quiescent fully closes said aperture, preventing
any discharge from the nozzle. The outer extremity of the valve plug is preferably
of an elongated tapering form, as illustrated; its middle, or that part which fills
and closes the aperture of the nozzle, is cylindrical to form a close fit for the nozzle
aperture, while its inner part is also tapering to form, as the valve is pressed out
of the nozzle, an annular outlet which increases in area in proportion to the
distance it is pressed out, as will be readily understood. From this inner tapering
part of the valve plug short radial ribs c, c, project, as shown in Figures 1 and 2,
but extend only to the same diameter as the cylindrical or plain part of the valve,
as illustrated, thus forming grooves between each other through which the air
escapes, while the ribs serve to guide the plug centrally in the nozzle aperture.
The stem d of the valve is provided either with adjustable weights or a strong
spring e, as illustrated, which constantly tends to keep the plug drawn in and thus
close the nozzle aperture, and which may be adjusted so as to place any desired
pressure on the valve, so that the jet will be discharged from the nozzle at this
pressure only. Where the jet is so arranged as to discharge upwardly weights
may be used to load the stem instead of a spring, but for all other situations I
prefer to use a strong spring, as shown in Figure 1, of such length that its tension
will not vary much with a slight compression or extension thereof. The spring
may be adjusted to place the required pressure on the valve by the adjusting and
jam nuts f, g, as will be readily understood, and the spring and stem may be
enclosed in an air tight tube projecting from the neck of the valve casing, thus
enabling the packing of the stem to be dispensed with, and therefore securing a
more sensitive action of the valve; but if desired the enclosing tube may be
omitted and the stem passed through a gland in, the neck of the valve casing,
leaving the spring and stem exposed. The nozzle is connected to the air supply
pipe preferably by a branch or coupling on the side of the casing A, as shown in
Figures 1 and 3, and for ordinary ventilating purposes the air is supplied to the
nozzle under a pressure of about 5 lbs to the square inch.
In Figure 3 is illustrated the one manner in which the improved nozzles are may
be arranged in a ventilating apparatus. Cindicates the apartment to be ventilated,
which may be in a war or passenger vessel, building, mine, or elsewhere; D is an air
compressing pump, which draws the air from the apartment or from the external
atmosphere and discharges the compressed air through the pipe l, which terminates
with several of the improved nozzles A¹ arranged in ventilating passages leading
into and out of the compartment. These nozzles are may be arranged to discharge
into contracted suction throats m, m, through which a large volume of atmospheric air
is thus induced to flow into and out of the apartment by the injecting action of the
jet, as will be readily understood, and these throats are preferably made adjustable
towards the nozzle so as to obtain the best relative position thereof. If the valves
of the injector nozzles be now set to the regular pressure and the air pump D put
in motion the nozzle valves will confine the air till it attains the desired pressure,
when the valve will open, allowing the discharge of an energetic jet from the
nozzle, having the required velocity and pressure to produce an effective inducing
action, and thus cause a strong induced current to flow through the suction throats
with the inducing, jet. Should however the speed of the pump decrease, rendering
the supply to the nozzle less, or should it increase, rendering the supply greater,
the nozzle valve will partly close or open correspondingly, thus causing the voluine
of the jet to always correspond to the volume of its supply, while its pressure and
velocity are maintained practically uniform, thus causing the jet to act to its
greatest efficiency under the different variations in volume, and producing under
different volumes a corresponding and full efficiency. By means of these unto-
matically acting nozzles it is found that the volume of the inducing jet being one
the volume of the induced current will be 35, thus-practically obtaining from-one
pump the capacity of 35 pumps. By means of these automatically acting nozzles it is
found that the volume of the induced current will be about from 25 to 40 times greater

page_text: than that of the inducing current, such increased volumes of the induced current varying
according to the conditions under which the nozzles are worked.
The improved nozzle may of course be used for producing air blasts or currents
for other purposes than ventilation, and it will also be understood that in some
eases the nozzle may be supplied with live steam instead of compressed air, but the
ase of the latter is more generally contemplated in some of which applications it may
be desirable to use live steam as the inducing current but such fluid is not adapted for the
purpose of ventilation. I sometimes prefer to construct the valve plug of the nozzle
so as to discharge a central jet as well as an annular one, the centre of the plug in
this case being provided with a bore arranged to embrace and slide over a tapering
plug fixed in the centre of the nozzle, as shown in Figure 4, but this is optional.
Having described the nature of the Invention, and the manner of performing
the same,
I declare that I do not claim the particular method of arranging the ventilating
passages provided with contracted suction throats shown in Figure 3 which merely
illustrates one manner in which the improved nozzles may be arranged in a ventilating
apparatus as the manner of applying the nozzles hereinafter claimed varies in accordance
with the particular requirements of each case but what I claim as the Invention to be
protected by the herein before in part receited Letters Patent is,—
An injector nozzle for producing blasts or currents of air constructed with an
automatic valve arranged to govern its discharge aperture, and adjustable by spring
or weights to open and discharge the jet at a certain determined pressure, whereby
the pressure and velocity of the jet is maintained practically uniform under varying
volumes, and its efficiency thus rendered constant and proportional to the volume
supplied, substantially as herein set forth.
In witness whereof, I, the said Alexander Melville Clark, have hereunto set
my hand and seal, this Fifth day of May, in the year of our Lord One
thousand eight hundred and eighty.

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lane, in the
County of Middlesex, Patent Agent, for the Invention of "IMPROVEMENTS
IN AIR INJECTING NOZZLES FOR VENTILATING AND OTHER PURPOSES." A
communication from abroad by David Culver Green, of Brooklyn, King's
County, State of New York, United States of America.
Sealed the 30th April 1880, and dated the 6th November 1879.
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark at
the Office of the Commissioners of Patents on the 6th November 1879.
"
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of
Middlesex, Patent Agent. IMPROVEMENTS IN AIR INJECTING NOZZLES FOR
VENTILATING AND OTHER PURPOSES." [A communication from abroad by David
Culver Green, of Brooklyn, King's County, State of New York, United States of
America.]
This Invention relates to apparatus for producing blasts or currents of air for
ventilation or other purposes by the injective action of jets of steam or compressed.
air discharged from nozzles into suction throats or tubes, through which a large
volume of air is thus caused to flow by the inducing action of the jet, and the
Invention is embodied mainly in an improved form of injection nozzle or jet
whereby the velocity and pressure of the jet is maintained independent of
variations in the volume supplied to it from the compressing pump or other
apparatus, thus greatly increasing the effectiveness of the jet, and causing its
effectiveness to at all times correspond proportionately with the volume supplied,
as hereinafter fully set forth.
In producing air currents or blasts by the injective or inducing action of jets,
it is necessary, as is well known, that the jet be discharged under a positive
pressure and at a high velocity in order to obtain an effective inducing action.
The pressure of course mainly determines the velocity of the jet, and it is found
that the best effect is obtained with a jet of a certain pressure and velocity, which
of course varies in different cases; but when this point is determined in each case
it cannot be much departed from without serious loss.
The volume of the jet is of course another element in its effectiveness, but if its
pressure and velocity be maintained its effectiveness will be also maintained, and

page_text: will correspond with its increase or decrease of volume, while if its power and
velocity be allowed to fall or vary much from the best determined point, the
increase in volume will give no corresponding effectiveness, but will be mainly
a loss of power. Hence the main defects in air jet nozzles as heretofore con-
structed, and which I am to overcome, is that they are formed with a discharge
aperture of a fixed and uniform area, so that to maintain the pressure and velocity
of the jet up to its point of greatest efficiency it is necessary that the compressing
pump or other source of supply form a constant volume corresponding to such
pressure and velocity from a jet of that area, and if the volume increase or decrease
beyond this point the area of the jet then of course becomes proportionately too
small or too large, hence causing the pressure and velocity of the jet to corre-
spondingly decrease or increase, and thus rendering its action inefficient.
Now the main feature of the present Invention may be stated to consist in
constructing the air jet nozzle with an automatic valve arranged to govern its
discharge aperture and loaded to open at a certain pressure, so that hence the jet
is discharged uniformly at this pressure, and should the supply to the jet decrease
in volume the valve will partly close to correspondingly reduce the area of the
discharge aperture, and thus maintain the uniform pressure and velocity of the
jet, and should the volume increase the valve will open wider, thus discharging
a jet of greater volume yet at practically the same pressure, thus maintaining the
efficiency of the jet under a varying supply, causing the volume of the induced
current to increase proportionately as the volume of the inducing jet increases.
The valve consists of a plug which is arranged in the aperture of the nozzle end
of the injector, and when quiescent fully closes said aperture, preventing any
discharge from the nozzle. The outer extremity of the valve plug is preferably
of an elongated tapering form; its middle, or that part which fills and closes the
aperture of the nozzle, is cylindrical to form a close fit for the nozzle aperture,
while its inner part is also tapering to form, as the valve is pressed out of the
nozzle, an annular outlet which increases in area in proportion to the distance it is
pressed out, as will be readily understood. From this inner tapering part of the
valve plug project short radial ribs, but which extend only to the same diameter
as the cylindrical or plain part of the valve, thus forming grooves between each
other through which the air escapes, while the ribs serve to guide the plug
centrally in the nozzle aperture. The stem of the valve is provided either with
adjustable weights or a strong spring which constantly tends to keep the plug
drawn in and thus close the nozzle aperture, and which may be adjusted so as to
place any desired pressure on the valve, so that the jet will be discharged from
the nozzle at this pressure only. Where the jet is so arranged as to discharge
upwardly weights may be used to load the stem instead of a spring, but for all
other situations I prefer to use a strong spring of such length that its tension will
not vary much with a slight compression or extension thereof. The spring may be
adjusted to place the required pressure on the valve by means of adjusting and
jam nuts on the stem, as will be readily understood, and the spring and stem may
be enclosed in an air tight tube projecting from the neck of the valve casing, thus
enabling the packing of the stem to be dispensed with, and therefore securing a
more sensitive action of the valve; but if desired the enclosing tube may be
omitted and the stem passed through a gland in the neck of the valve casing,
leaving the spring and stem exposed.
The nozzle is connected to the air supply pipe preferably by a branch or
coupling on the side of the casing, and for ordinary ventilating purposes the air
is supplied to the nozzle under a pressure of about 5 lbs. to the square inch.
For ventilating purposes an air compressing pump would be employed drawing the
air from the apartment or other place to be ventilated, or from the external
atmosphere, and discharging the compressed air through a pipe terminating with
several of the improved nozzles arranged in ventilating passages leading into and
out of the apartment. These nozzles are arranged to discharge into contracted
suction throats, through which a large volume of atmospheric air is thus induced

page_text: to flow into and out of the apartment by the injecting action of the jet, as will be
readily understood, and these throats are preferably made adjustable towards the
nozzle so as to obtain the best relative position thereof. If the valves of the
injector nozzles be now set to the regular pressure and the air pump put in motion
the nozzle valves will confine the air till it attains the desired pressure, when the
valve will open allowing the discharge of an energetic jet from the nozzle having
the required velocity and pressure to produce an effective inducing action, and thus
cause a strong induced current to flow through the suction throats with the
inducing jet. Should however the speed of the pump decrease rendering the
supply to the nozzle less, or should it increase rendering the supply greater,
the nozzle valve will partly close or open correspondingly, thus causing the volume
of the jet to always correspond to the volume of its supply, while its pressure and
velocity are maintained practically uniform, thus causing the jet to act to its
greatest efficiency under the different variations in volume, and producing under
different volumes a corresponding and full efficiency. By means of these auto-
matically acting nozzles it is found that the volume of the inducing jet being one
the volume of the induced current will be thirty five, thus practically obtaining
from one pump the capacity of thirty five pumps. The improved nozzle may of
course be used for producing air blasts or currents for other purposes than ven-
tilation, and it will also be understood that in some cases the nozzle may be
supplied with live steam instead of compressed air, but the use of the latter is more
generally contemplated. I sometimes prefer to construct the valve plug of the
nozzle so as to discharge a central jet as well as an annular one, the centre of
the plug in this case being provided with a bore arranged to embrace and slide
over a tapering plug fixed in the centre of the nozzle, but this is optional.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Alexander Melville Clark in the Great Seal Patent Office on the 6th
May 1880.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of
Middlesex, Patent Agent. "IMPROVEMENTS IN AIR INJECTING NOZZLES FOR
VENTILATING AND OTHER PURPOSES." A communication from abroad by David
Culver Green, of Brooklyn, King's County, State of New York, United States of
America.
This Invention relates to apparatus for producing blasts or currents of air for
ventilation or other purposes by the injective action of jets of steam or compressed
air discharged from nozzles into suction throats or tubes, through which a large
volume of air is thus caused to flow by the inducing action of the jet, and the
Invention is embodied mainly in an improved form of injection nozzle or jet
whereby the velocity and pressure of the jet is maintained independent of varia-
tions in the volume supplied to it from the compressing pump or other apparatus,
thus greatly increasing the effectiveness of the jet and causing its effectiveness to
at all times correspond proportionately with the volume supplied, as hereinafter
fully set forth.
The
In producing air currents or blasts by the injective or inducing action of jets it is
necessary, as is well known, that the jet be discharged under a positive pressure
and at a high velocity in order to obtain an effective inducing action.
pressure of course mainly determines the velocity of the jet, and it is found that
the best effect is obtained with a jet of a certain pressure and velocity which varies
in different cases, but when this point is determined in each case it cannot be much
departed from without serious loss. The volume of the jet is of course another
element in its effectiveness, but if its pressure and velocity be maintained its
effectiveness will be also maintained and will correspond with its increase or
decrease of volume, while if its power and velocity be allowed to fall or vary much
from the best determined point the increase in volume will give no corresponding
effectiveness but will be mainly a loss of power. Hence the main defects in air
jet nozzles as heretofore constructed, and which I am to overcome, is that they are
formed with a discharge aperture of a fixed and uniform area, so that to maintain
the pressure and velocity of the jet up to its point of greatest efficiency it is
necessary that the compressing pump or other source of supply form a constant
volume corresponding to such pressure and velocity from a jet of that area, and if
the volume increase or decrease beyond this point the area of the jet then of course
becomes proportionately too small or too large, hence causing the pressure and
velocity of the jet to correspondingly decrease or increase, and thus rendering its
action inefficient.
Now the main feature of the present Invention may be stated to consist in
constructing the air jet nozzle with an automatic valve arranged to govern its
discharge aperture, and loaded to open at a certain pressure, so that hence the jet
is discharged uniformly at this pressure, and should the supply to the jet decrease
in volume the valve will partly close to correspondingly reduce the area of the
discharge aperture, and thus maintain the uniform pressure and velocity of the jet,
and should the volume increase the valve will open wider, thus discharging a jet of
greater volume, yet at practically the same pressure, thus maintaining the
efficiency of the jet under a varying supply, causing the volume of the induced
current to increase proportionately as the volume of the inducing jet increases.
Figure 1 in the accompanying Drawings is a longitudinal section of the improved
air injector nozzle, and Figure 2 a cross section of its valve plug on line x, x.
Figure 3 represents a ventilating apparatus provided with the improved nozzles.
In Figure 1 A indicates the casing or body of the improved injector valve or

page_text: nozzle, and b the nozzle end thereof, in the aperture of which, as illustrated, is
arranged a valve plug B, which when quiescent fully closes said aperture, preventing
any discharge from the nozzle. The outer extremity of the valve plug is preferably
of an elongated tapering form, as illustrated; its middle, or that part which fills
and closes the aperture of the nozzle, is cylindrical to form a close fit for the nozzle
aperture, while its inner part is also tapering to form, as the valve is pressed out
of the nozzle, an annular outlet which increases in area in proportion to the
distance it is pressed out, as will be readily understood. From this inner tapering
part of the valve plug short radial ribs c, c, project, as shown in Figures 1 and 2,
but extend only to the same diameter as the cylindrical or plain part of the valve,
as illustrated, thus forming grooves between each other through which the air
escapes, while the ribs serve to guide the plug centrally in the nozzle aperture.
The stem d of the valve is provided either with adjustable weights or a strong
spring e, as illustrated, which constantly tends to keep the plug drawn in and thus
close the nozzle aperture, and which may be adjusted so as to place any desired
pressure on the valve, so that the jet will be discharged from the nozzle at this
pressure only. Where the jet is so arranged as to discharge upwardly weights
may be used to load the stem instead of a spring, but for all other situations I
prefer to use a strong spring, as shown in Figure 1, of such length that its tension
will not vary much with a slight compression or extension thereof. The spring
may be adjusted to place the required pressure on the valve by the adjusting and
jam nuts f, g, as will be readily understood, and the spring and stem may be
enclosed in an air tight tube projecting from the neck of the valve casing, thus
enabling the packing of the stem to be dispensed with, and therefore securing a
more sensitive action of the valve; but if desired the enclosing tube may be
omitted and the stem passed through a gland in the neck of the valve casing,
leaving the spring and stem exposed. The nozzle is connected to the air supply
pipe preferably by a branch or coupling on the side of the casing A, as shown in
Figures 1 and 3, and for ordinary ventilating purposes the air is supplied to the
nozzle under a pressure of about 5 lbs to the square inch.
In Figure 3 is illustrated the manner in which the improved nozzles are arranged
in a ventilating apparatus. C indicates the apartment to be ventilated, which may
be in a war or passenger vessel, building, mine, or elsewhere; D is an air com-
pressing pump, which draws the air from the apartment or from the external
atmosphere and discharges the compressed air through the pipe l, which terminates
with several of the improved nozzles A¹ arranged in ventilating passages leading
into and out of the compartment. These nozzles are arranged to discharge into
contracted suction throats m, m, through which a large volume of atmospheric air
is thus induced to flow into and out of the apartment by the injecting action of the
jet, as will be readily understood, and these throats are preferably made adjustable
towards the nozzle so as to obtain the best relative position thereof. If the valves
of the injector nozzles be now set to the regular pressure and the air pump D put
in motion the nozzle valves will confine the air till it attains the desired pressure,
when the valve will open, allowing the discharge of an energetic jet from the
nozzle, having the required velocity and pressure to produce an effective inducing
action, and thus cause a strong induced current to flow through the suction throats
with the inducing jet. Should however the speed of the pump decrease, rendering
the supply to the nozzle less, or should it increase, rendering the supply greater,
the nozzle valve will partly close or open correspondingly, thus causing the volume
of the jet to always correspond to the volume of its supply, while its pressure and
velocity are maintained practically uniform, thus causing the jet to act to its
greatest efficiency under the different variations in volume, and producing under
different volumes a corresponding and full efficiency. By means of these auto-
matically acting nozzles it is found that the volume of the inducing jet being one
the volume of the induced current will be 35, thus practically obtaining from one
pump the capacity of 35 pumps.
The improved nozzle may of course be used for producing air blasts or currents

page_text: for other purposes than ventilation, and it will also be understood that in some
cases the nozzle may be supplied with live steam instead of compressed air, but the
use of the latter is more generally contemplated. I sometimes prefer to construct
the valve plug of the nozzle so as to discharge a central jet as well as an annular
one, the centre of the plug in this case being provided with a bore arranged to
embrace and slide over a tapering plug fixed in the centre of the nozzle, as shown
in Figure 4, but this is optional.
Having described the nature of the Invention, and the manner of performing
the same, I declare that what I claim as the Invention to be protected by the
herein before in part recited Letters Patent is,―
An injector nozzle for producing blasts or currents of air constructed with an
automatic valve arranged to govern its discharge aperture, and adjustable by spring
or weights to open and discharge the jet at a certain determined pressure, whereby
the pressure and velocity of the jet is maintained practically uniform under varying
volumes, and its efficiency thus rendered constant and proportional to the volume
supplied, substantially as herein set forth.
In witness whereof, I, the said Alexander Melville Clark, have hereunto set
my hand and seal, this Fifth day of May, in the year of our Lord One
thousand eight hundred and eighty.
A. M. CLARK. (L.S.)