U.S. patent number 3,589,383 [Application Number 04/846,423] was granted by the patent office on 1971-06-29 for device for driving a fluid.
Invention is credited to Michel Garnier.
United States Patent |
3,589,383 |
Garnier |
June 29, 1971 |
DEVICE FOR DRIVING A FLUID
Abstract
Device for driving a secondary fluid by a primary fluid
comprising a first intake pipe for the primary fluid and a second
intake pipe for the secondary fluid which is coaxial to the first
pipe, at least one symmetrical bulb is lodged coaxially in the
second pipe, with the downward end of the first pipe providing a
slit between it and the upward portion of the bulb for the flowing
of the primary fluid therethrough whereby the primary fluid issues
from the slit in a path substantially tangential to the outer
profile of the bulb from upward to downward, the downward end of
the bulb being truncated.
Inventors: |
Garnier; Michel (Paris,
FR) |
Family
ID: |
26182164 |
Appl.
No.: |
04/846,423 |
Filed: |
July 31, 1969 |
Foreign Application Priority Data
Current U.S.
Class: |
137/806; 60/316;
60/308; 417/159; 417/151; 417/198 |
Current CPC
Class: |
F04F
5/466 (20130101); B01F 3/02 (20130101); B01F
3/0446 (20130101); B01F 5/0451 (20130101); B01F
15/0201 (20130101); F04F 5/463 (20130101); F04F
5/467 (20130101); B01F 5/0293 (20130101); B01F
5/0453 (20130101); B01F 5/0456 (20130101); B01F
5/0656 (20130101); B01F 5/0458 (20130101); F23D
14/62 (20130101); B01F 2015/0221 (20130101); B01F
2013/1052 (20130101); Y10T 137/2076 (20150401) |
Current International
Class: |
F23D
14/46 (20060101); F23D 14/62 (20060101); B01F
3/00 (20060101); B01F 15/02 (20060101); F04F
5/00 (20060101); B01F 3/04 (20060101); B01F
3/02 (20060101); B01F 5/06 (20060101); B01F
5/04 (20060101); F04F 5/46 (20060101); B01F
13/10 (20060101); B01F 13/00 (20060101); F15d
001/02 () |
Field of
Search: |
;137/81.5 ;138/39 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Scott; Samuel
Claims
What I claim is:
1. Device for driving a secondary fluid by a primary fluid
comprising a first intake pipe for the primary fluid and a second
intake pipe for the secondary fluid which is coaxial to the first
pipe, at least one symmetrical bulb lodged coaxially into the
second pipe with its maximum diameter disposed on the upward side
of the intake pipes, the downward end of said bulb being truncated,
said first pipe entering axially into the upward front portion of
said bulb and extending into a channel opening tangentially through
the outer wall of said upward front portion of said bulb, a gap
between the downward end of said first pipe and the upward portion
of said bulb, said gap being so arranged that the primary fluid
flowing therethrough circulates in a substantially tangential flow
along the outer profile of the bulb from upward to downward.
2. Device for driving a secondary fluid by a primary fluid
comprising a first intake pipe for the primary fluid and second
intake pipe for the second fluid, both pipes being coaxial, a bulb
unit disposed coaxially within said pipes, said unit comprising at
least two bulbs with the maximum diameter disposed on the upward
side of the intake pipes and decreasing from the upward bulb to the
downward bulb, a curved connection between the downward end of the
upward bulb and the upward front end of the next downward bulb, the
downward end of said downward bulb being truncated, a slit between
the downward end of the first intake pipe and the upward front
portion of the upward bulb, whereby the primary fluid issues from
the slit in a path substantially tangential to the outer profile of
the upward bulb from upward to downward and follows then the
connection and the profile of the downward bulb.
3. In a device as claimed in claim 2, means to provide a slit
around the slightest diameter of the connection between two
successive bulbs and the upward front portions of the following
bulb.
Description
The present invention relates to improvements to the driving of an
important mass of fluid by a smaller mass of fluid of high energy.
The invention relates also to the industrial applications of the
said improvements.
Many applications of the Coanda effect are already well known but
it has been observed that the cross section of the nozzle throat
kept down frequently the effectiveness and thus the efficiency of
this latter. Tests have been carried out and have shown that when
the Coanda slit was opened at a given dimension, the total flow
produced (driven fluid and driving fluid) was such that the throat
was in effect saturated, i.e., that its cross section was not big
enough to let the total flow pass without braking it.
The research work carried out in order to eliminate this drawback
and to hold and if possible to develop the full advantages of the
Coanda effect, has lead to observe that this performance was very
simply reached with a nozzle, which can be termed "external
nozzle," cooperating with a slit whose extended lip is located
externally from the rolled profile of a streamlined body, which
will be referred to as "bulb" in the description hereafter.
Proceeding from this basis, the improvements to the carrying into
effect of the Coanda effect consist essentially, according to the
present invention, in sending under pressure a driving or primary
fluid on the upstream edge of intake edge of a streamlined body in
form of symmetrical bulb, immersed into a fluid to be driven or
secondary fluid, the arrival of the primary fluid taking place
coaxially with the axis of the said bulb, and the coming out of
this primary fluid into the secondary fluid being tangential to the
curvature of the bulb from upstream to downstream. The input of the
fluid under pressure can take place internally or externally from
the bulb, but in every case in such a manner that the flow of the
outcoming fluid be always tangential to the curvature of the bulb
from upstream to downstream, and following the curvature of said
bulb.
The carrying into effect of these improvements is ensured by a
device consisting essentially, in its more general form, of a
profile rolled around an axis and having the shaped of a
streamlined body or symmetrical bulb, by tubular means coaxial with
the said bulb and opening in the vicinity of the upstream surface
of the bulb for driving there the primary fluid, and by means
suitable for driving the said primary fluid to be tangent to the
curvature of the bulb from upstream to downstream.
According to another feature of the invention, the above-mentioned
improvements include the arrangement of a chamber either
cylindrical or of a diameter higher than the maximum diameter of
the bulb, either in a shape of truncated, convergent or divergent
cone, but in all cases coaxial with the bulb. The said chamber can
stretch from a point located before the intake edge up to a point
located at a given distance below the rear end of the bulb. The
bulb can also be located completely on the axis of the cylindrical
room and before this latter, by selecting, will be disclosed later
on, the respective dimensions of the bulb and of the chamber as
well as the distance between the entrance of the chamber and the
rear end of the bulb. The chamber can particularly be made of a
complete venturi or of its conical portions, eventually
interconnected by a cylindrical portion.
It has been observed that, under the conditions explained
hereabove, the secondary fluid flow obtained was much higher than
with a simple external bulb nozzle of same characteristics, while a
lower efficiency was normally expected in view of the load losses
resulting from the fluid coming into contact with the wall of the
cylindrical chamber.
The primary fluid and the secondary fluid can be similar or
different. The primary fluid supply can be continuous or pulsatory,
for example it can be provided by the exhaust gas of an engine.
The bulb can be fitted as indicated hereabove, either completely
above the chamber pipe, or partly at the external side above the
said pipe and partly into the chamber pipe, or partly below this
pipe. The position of the bulb in relation with the chamber pipe
can be selected in terms of the desired velocity of the flow at the
outlet of the device according to the invention, and dependent on
the mass of fluid whose driving is desired.
The bulb can be made of a surface of revolution which can be total
or partial; it can also have the shape of a single wing, or of a
double, preferably symmetrical, wing, with the wall enveloping the
bulb being then made of at least one plane parallel to the axis of
the wing. The surface of the bulb can also be interrupted at a
certain distance below the main cross section, which allows to
increase the diffusion of the mass coming out from the device.
The outlet of the primary or driving fluid can be made of a regular
slit, of an interrupted slit or of a series of holes.
Inside a chamber and according to the desired performances, it is
possible to fit either several identical or different parallel-axis
bulbs or one single bulbous body made of bulbs mutually overlapping
in order to form lobes. Adjacent to each other it is also possible
to arrange several cylindrical chambers mutually overlapping in
form of lobes, and to set up a bulb inside of each lobe.
It has been observed that, in a general manner, with D being the
diameter of the bulb at the main cross section and d being the
diameter of the slit, .DELTA. being the diameter of the cylinder
surrounding the bulb or the bulbous body, it was recommended
that:
D/d 2, in relation with the pressure of the primary fluid, .DELTA.
be selected on the one side in relation with the result desired,
with a value eight or 10 times higher than d when speed of the
total flow is desired at the exhaust, and a value higher than 20 d
when a big flow of the stream is desired. It has also been observed
that, according to the invention, the highest induction ratio was
obtained with low primary pressures (in the order of 20
g./cm..sup.2 approximately) and thin slits (in the order of 0.1
mm.).
As for the length L of the cylinder, it has been observed still
according to the invention, that the best driving action of the
secondary fluid by the primary one is obtained with the following
relation between L and .DELTA., the bulb being located at the
upstream input of the cylinder: 3.DELTA.<L <5.DELTA..
On the other side, the position of the bulb in relation with the
input of the chamber pipe, does not apparently load to a noticeable
variation of the efficiency of the device.
The process and the device according to the invention are likely to
have many industrial applications, such as: driving of air to
provide ventilation effects --production of high velocity streams
in order to allow for very remote localized aerations--mixing of
two or more fluids, for example for burners--extraction of gas by
means of the local depression produced by the coming out of the
primary gas, improving namely the exhaust of internal combustion
engines --spraying of liquids for different processes --handling of
pulverulate or granulate materials. These different applications of
the device according to the invention have efficiencies and an
effectiveness much higher than those obtained with the already
known apparatus.
With some of these applications, it is possible to use to the best
the wall effect resulting from the presence of the chamber pipe or
other, by proving the modification of the said pipe diameter; it is
also possible to modify the length of the pipe with or without air
input into wall, by using for example a concentric tube, a hole
made free by sliding, a telescopic tube or other.
Among the above-mentioned applications, it was found the mixing of
one or more fluids, intended for being used in burners; in this
case, a grid could be fitted at the outlet of the external chamber
of the device for carrying into effect the said improvements. In
such a case of gas burner, it has been indicated above that a
practically total automaticity of adjustment of the oxydizing air
in relation with gas was obtained, with any type of gas, volume and
pressure whatsoever, as the flow can only be adjusted by the
pressure of the primary gas (fuel).
A form of embodiment particularly advantageous of a gas burner,
where this burner consists, on the one side, of a mixer portion
made of a bulb according to a main patent, of a pipe feeding
coaxially with the bulb the fuel primary gas and driving it into a
slit made between the end of the pipe and the upstream portion of
the bulb around this latter, of a pipe whose both ends are opened
and conically flared upstream and downstream in order to
accommodate an inlet for the ambient fluid (oxydizer) between the
upstream portion of the bulbous body and the downstream portion of
the pipe, the conical upstream portion of said pipe stretching up
to a small distance above the slit for injection of the primary gas
in order to form a primary chamber for mixing the primary fluid and
and oxydizing fluid, and a cylindrical channel surrounding the
whole said pipe stretching beyond the downstream end of said pipe,
on the other side of a grid fitted at the outlet of the final
mixing chamber comprised between the upstream end of the conical
pipe and the channel, the final mixture being inflamed by any
appropriate means at the grid outlet.
In the case when several bulbs are mounted in series in the intake
pipe for the primary fluid, there is advantageous to use one bulb
element along, composed of bulbs which are solidarized from the one
to the other through their respective upward and downward ends, the
maximum diameters of which decreasing from the one to the other and
which are individually provided on its upward front with a slit
receiving the primary fluid issued from the preceeding bulb element
and possibly mixed with secondary driven fluid, so that the fluid
issuing from said second element penetrates into the slit of the
third bulb element and so on, the last bulb element being truncated
at its downward end.
By referring to the appended drawings, some examples of the
carrying into effect of improvements and applications according to
the invention.
In these drawings:
FIG. 1 is a diagrammatic view in axial cross section of the device
according to the invention;
FIG. 2 is similar view of another embodiment;
FIGS. 3 and 4 are respectively views in longitudinal cross section
according to the line 4-4 of FIG. 3 of a lobed device;
FIG. 5 illustrates in axial cross section a device for fluids
spraying;
FIG. 6 is a sectional view of a device for the handling of
materials;
FIGS. 7, 8 and 9 represent respectively: diagrammatic sectional
views of a tandem of bulbs according to the invention, a bulb fed
by a nozzle and of a nozzle fed by a bulb according to the
invention;
FIG. 10 illustrates an adjustable aeration device;
FIG. 11 illustrates an adjustable slit device;
FIG. 12 is graph showing the results obtained with an aeration
device according to the invention.
FIG. 13 is longitudinal axial section view of an example of
preferred embodiment of a mixer burner according to the
invention;
FIG. 14 is a schematical sectional views of another embodiment of
the device shown on FIG. 7.
In the drawings, the device according to the invention is
illustrated with a bulb 1 having an upstream portion 2, a main
cross section 3 and a streamlines downstream portion 4, which can
moreover be real only up to a certain distance from its tip. The
primary fluid supply is provided by a pipe 5 coaxial with bulb 1.
In the case of FIG. 1, the pipe 5 is flared with a slit 6 between
the upstream portion 2 and a wall 7. In FIG. 2, the pipe 5 enters
the upstream body 2 and opens externally above the main cross
section 3, by an annular slit 6. The bulb 1 is located coaxially
into a cylindrical pipe 8: it has been observed that this pipe
facilitated the driving effect produced on the the secondary fluid
by the primary fluid coming out, tangentially from the bulbous
body, from the slit 6. In case the device has to be used as a gas
burner, a grid can be fitted at the output hole of the external
chamber (FIG. 11).
The device of FIGS. 3 and 4 embodies three bulbs 1, 1.sub.1 and
1.sub.2 located into a chamber 8 with three lobes 8.sub.1, 8.sub.2
and 8.sub.3 which have a primary fluid supply provided by a pipe 5
fitted with branches 5.sub.1, 5.sub.2 and 5.sub., each of them
being connected to one of the slits of the three bulbs. A variable
volume ventilation can thus be provided by the working of one or
more bulbs of the lobe. The arrows illustrate the path of the
fluid.
The device illustrated into FIG. 5 is particularly convenient for
the spraying of a driven fluid. In this example, the bulb 1 has its
downstream portion 4 truncated in 4' and an arrival 9 of liquid is
arranged internally of the bulb at the surface of which it comes
out from holes 9 uniformly distributed at the vicinity of the main
cross section 3. A ring or similar 10 allows to vary, if desired,
the free surface of flow of the openings 9. A modified device
consists of a bulb 1 at the output of the sleeve 8, the liquid to
be sprayed arriving on the external surface of the bulb by any
appropriated means already known. Under these conditions, we obtain
in one or another embodiment, an extreme fragmentation of the
liquid which is thus perfectly sprayed. The truncated portion 4'
favors still more this spraying when the arrival of the liquid to
be sprayed is made at the downstream end of the bulb and even at a
certain distance downstream on the axis of the bulb; we obtain thus
locally a very strong eddy effect which avoids any deposition and
dripping, as the spraying is only produced externally from the
sleeve.
The device illustrated in FIG. 6 is intended for transporting
pulverulate material. In this effect, the pipe 5 for the primary
fluid supply has a conical cap 11 on which the material 12 arrives,
driven by the secondary fluid used as support. The material is then
driven with the secondary fluid. The conical cap 11 could be
replaced by an helicoidal surface; we could also simply provide a
slit of a circular series of additional holes 11' at the vicinity
of the outcoming pipe 5 on the downstream portion 2 of bulb 1. The
holes or helix provide centrifugal ejection of the particulate
material into the secondary fluid and the material handling is
carried out as desired. In FIG. 7, two bulbs 1' and 1" constituting
a bulb unit are mounted in tandem, the first one 1' being placed in
a cylindrical chamber 5" providing a curved connection. The second
bulb 1" is placed in a pipe 8. The pipe 5' discharges through a
slit 6' between the flared end of the pipe 5' and the adjacent end
of the bulb 1'. The cylindrical chamber 5" discharges through a
slit 6" between the mutually adjacent ends of the chamber 5" and
the bulb 1".
In the case of FIG. 8, a Coanda nozzle 11 of known type is made to
stream directly by its venturi 14 into the slit 15 of a bulb 1
located coaxially into a pipe 8.
The FIG. 9 illustrates a bulb 1 fed by a pipe 5 and located into
the cylindrical pipe 8 in such a manner that the bulb and the pipe
outlets are located approximately into the throat of the known type
Coanda nozzle 16. We observe that a very favorable action is thus
obtained on the homogeneity of the output stream.
The device illustrated in FIG. 10 is made on the one side of a bulb
1 with its supply 5 in primary fluid such as air in order to drive
a secondary fluid such as air, for ensuring the aeration of
premises, on the other side of a pipe made of two parts 8.sub.1 and
8.sub.2 which can mutually slide, with a gap 17 between them. In
the position illustrated in the upper part of FIG. 10, the gap 17
is opened and we obtain the driving of a constant air volume at low
velocity. In the position illustrated in the lower part of FIG. 10,
the two parts 8.sub.1 and 8.sub.2 of the pipe are entered and we
obtain the driving of a constant volume of air at high velocity. If
the bulb 1 is mounted inside the first pipe, concentric to an
external pipe used as channel, we can obtain a high flow
ventilation under low pressure.
The device according to the invention can work with a high
versatility when the dimensions of the driving slits are made to
vary as illustrated as example in FIG. 11. We see there a bulb 1
rotatably mounted by any appropriate means already known inside a
cylinder 21 with curved surface, in order to form at the vicinity
of the bulb 1 an essentially cylindrical channel. The slit 6 is
then of such a shape that its free depth is constant for the
different slopes of the bulb 1 in relation with the axis. We can
also fit the cylinder pipe with any known device likely to modify
its diameter.
A numerical example of the tandem arrangement according to the FIG.
7 has been subjected to different tests. We have used a ventilation
apparatus where the bulb 1' had a slit 6 of a 26 mm. diameter, a
main cross section 3' of a 48 mm. diameter and a length of 160 mm.
The internal diameter of the pipe 5' was 100 mm., its length 310
mm. The diameter of the slit 6' was 130 mm. The bulb 1" had a main
cross section 3" of a 176 mm. diameter. Its length was 420 mm. The
pipe 8 had an internal diameter of 410 mm. and a length of 1,000
mm. The performances obtained have been plotted on the graph (FIG.
12) for an opening of the slit 6' of 0.125 mm. and for an opening
of the slit 6" of 10 mm. The pressures in bars have been plotted
horizontally, and the flow in liters per second vertically
rightwards for the primary flow in liters and leftwards for the
total flow. The solid-line curve indicates the total flow in liters
per second; the primary flow in liters per second is indicated by
the dashed lines, and the curve in mixed lines indicates the ratio
"total flow/primary flow."
FIG. 13 shows a bulb 1 of the type described into the main patent,
with an axial pipe 2 for the fuel fluid supply, this pipe 2 opening
into a slit 3 on the wide upstream portion 4 of the bulb 1. The
bulb 1 is located coaxially with the internal part of the venturi
5, with a converging short section 6 and a long diverging section
7, connected through the throat 8 essentially at the same level as
the slit 3. Finally, the whole venturi 5 and bulb 1 is located
coaxially inside a cylindrical envelop 9 which extends from the
level of the throat 8 to the downstream side of the end of the
diverging part 7. A grid 10 is mounted perpendicularly to the axis
of the whole, at the downstream end of the envelop 9. The
above-mentioned device is mounted for example on supports 11, into
an environment 12 of oxydizer such as air.
The operation of the device is as follows: the fuel gas, for
example propane or butane, is driven under the desired pressure
through the pipe 2, wherefrom it comes off the slit 3 along the
wide upstream portion 4 of the bulb 1; the fluid drives air from
the environment 12 into the annular channel 13 accommodated between
the venturi 5 (converging part 6, throat 8), the bulb 1 and the
diverging part 7. A first mixture of fuel fluid and oxydizing air
is thus formed into the space inside the diverging part. At the
outlet of the diverging part 7, ambient air is added to this
premixture which it receives from the annular channel 14 included
between the envelop 9 and the external part of the diverging
portion 7. The final mixture is then driven to the grid 10 where it
can be inflamed for any proposed application.
In the embodiment according to FIG. 14, the device comprises a bulb
unit 11', disposed in line along the inlet axes of the primary and
secondary fluids, inside of the piping 8 for the driven air
(secondary fluid) and in prolongation to the intake pipe 5 of
primary fluid (driving air). The unit is here formed with element
111.sub.1, 111.sub.2 and 111.sub.3, which provide maximal diameters
103.sub.1, 103.sub.2, 103.sub.3 decreasing from upward to downward
and which are connected from the one to the other by a thinner
portion 104.sub.1, 104.sub.2, 104.sub.3 ; on the upward front of
each element there is provided a slit, respectively 106.sub.1,
106.sub.2, 106.sub.3. The pipe 5 for the primary air must be
located on the front of the first element 111.sub.1 ; the primary
fluid passes through the slit 106.sub.1 and drives therewith
secondary fluid (driven air) tangentially to the outer profile of
element 111.sub.1, wherefrom its issues being added with a
supplemental quantity of secondary fluid, and is in turn driven
tangentially into the slit 106.sub.2 of the second element
111.sub.2, to come then into the slit 106.sub.3 of element
111.sub.3 and so on.
If the device works as a burner, we have observed the remarkable
fact as follows: under the conditions of the device according to
the invention, it is always obtained a complete automaticity of the
adjustment of the oxydizing air in relation with the gas, with any
gas, volume or pressure whatsoever, i.e., the invention allows here
to be in any case under the optimum conditions of mixture
combustion, as the thermal flow can be adjusted by only acting on
the pressure of the primary gas (fuel) by maintaining a practically
optimum carbureted mixture. This is of course of great practical
interest, namely in view of the quality of the heating and of the
safety, which are automatically ensured.
* * * * *