U.S. patent number 3,577,711 [Application Number 04/829,125] was granted by the patent office on 1971-05-04 for apparatus for removing entrained particles from gases.
Invention is credited to Luigi U. De Bernardo.
United States Patent |
3,577,711 |
De Bernardo |
May 4, 1971 |
APPARATUS FOR REMOVING ENTRAINED PARTICLES FROM GASES
Abstract
An apparatus for removing entrained particles from gases, of
particular use as a spark arrester with internal combustion
engines, comprises, essentially, an elongated cylinder, closed at
one end and having a spiral member secured to the inner wall.
Exhaust gases enter tangentially at a point near the open end and
travel in a thin layer along a spiral path adjacent the wall toward
the closed end. Near the closed end, the gases reverse direction
and travel in an axial spiral path along the center of the cylinder
and out the open end, while incandescent carbon particles continue
by inertia in their original spiral path and are retained or
pulverized by rubbing against the cylinder wall as they continue to
circulate at the base of the cylinder. The absence of baffles
minimizes back pressure on the engine.
Inventors: |
De Bernardo; Luigi U. (San
Dimas, CA) |
Assignee: |
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Family
ID: |
25253594 |
Appl.
No.: |
04/829,125 |
Filed: |
June 2, 1969 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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592888 |
Nov 8, 1966 |
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Current U.S.
Class: |
55/399;
55/DIG.30; 55/448; 55/459.5; 55/456 |
Current CPC
Class: |
F01N
3/06 (20130101); F01N 3/037 (20130101); Y02T
10/12 (20130101); Y02T 10/20 (20130101); Y10S
55/30 (20130101) |
Current International
Class: |
F01N
3/00 (20060101); F01N 3/037 (20060101); F01N
3/06 (20060101); B01d 045/12 () |
Field of
Search: |
;55/399,448,456,459 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Talbert, Jr.; Dennis E.
Parent Case Text
This application is a continuation-in-part of Ser. No. 592,888,
filed Nov. 8, 1966, now abandoned.
Claims
I claim:
1. Apparatus for removing entrained hot particles from internal
combustion engine exhaust gases comprising:
a. an elongated cylinder having an inlet port in the cylinder wall
near one end;
b. an inlet nozzle secured to the cylinder at said inlet port at
such angle that an inner wall of said nozzle is tangent to the
inner wall of the cylinder at their point of contact, said nozzle
having a decreasing taper in the direction of the cylinder, said
decreasing taper being obtained by providing a flat, ramplike
portion on the side of the nozzle opposite to the tangent wall;
c. means for connecting the nozzle to the exhaust pipe of an
internal combustion engine; and
d. a spiral guide member secured to the inner wall of the elongated
cylinder, said spiral advancing from a point between the inlet port
and the proximal open end of the cylinder for a distance not more
than 75 percent of the length of the cylinder, said spiral guide
member comprising approximately 1 percent of the cross-sectional
area of the cylinder.
2. Apparatus for removing entrained hot particles from internal
combustion engine exhaust gases comprising:
a. a first elongated cylinder having a closure plate at one end, an
open end, and an inlet port in the cylinder wall near the open
end;
b. an inlet nozzle connected to said first cylinder at said inlet
port at such an angle that an inner wall of the nozzle is tangent
to the inner wall of said first cylinder at their point of contact;
said nozzle having a decreasing taper in the direction of said
first cylinder, said taper being obtained by providing a flat,
ramplike portion on the side of the nozzle opposite the tangent
wall;
c. means for connecting the nozzle to the exhaust pipe of an
internal combustion engine;
d. a spiral guide member secured to the inner wall of said first
elongated cylinder, said spiral commencing at a point between the
open end of the cylinder and the inlet port and advancing toward
the closed end of the cylinder for a distance not more than 75
percent of the length thereof, said spiral guide member comprising
approximately 1 percent of the cross-sectional area of said first
cylinder;
e. a second elongated cylinder, having a smaller diameter than the
first cylinder, disposed coaxially in said first cylinder and
extending outward through the open end thereof; and
f. ring means inside the open end of the first cylinder for
securing the second cylinder and for closing the annular space
between said first and second cylinders.
3. The apparatus of claim 2 wherein the diameter of the second
cylinder is about one-half that of the first cylinder and extends
inward for about half the length of said first cylinder.
4. The apparatus of claim 2 wherein the spiral guide member is of
uniform pitch and advances toward the closed end of the first
cylinder for from 2 to 21/2 turns, commencing at the ring
means.
5. The apparatus of claim 4 wherein the entry port is located
within the first turn of the spiral guide member.
6. The apparatus of claim 2 wherein the closure plate is replaced
by a plate having a central opening therein and an aspirating tube
extending coaxially inward from said central opening.
7. The apparatus of claim 6 wherein the central opening in the
closure plate and the aspirating tube are about one-twelfth the
diameter of the first cylinder and said aspirating tube extends
inwardly to a point within the last turn of the spiral guide
member.
8. Apparatus for removing entrained hot particles from internal
combustion engine exhaust gases comprising:
a. a first elongated cylinder having an inlet end for receiving hot
exhaust gases, and an outlet end;
b. a second elongated cylinder having a diameter equal to that of
the first cylinder for ejecting gases to the atmosphere;
c. a third cylinder intermediate the first and second cylinders
having a diameter greater than that of said first and second
cylinders, said three cylinders being all disposed on a common
axis;
d. a first connecting piece joining the outlet end of the first
cylinder with the proximal end of the third cylinder, said first
connecting piece having a first conical portion tapering inward
from the outlet end of the first cylinder to a diameter smaller
than that of the first cylinder, followed by a second conical
portion tapering outward to a diameter equal to that of the third
cylinder to join the outlet end of the first cylinder to the
proximal end of the third cylinder;
e. a second connecting piece comprising a conical member extending
from the distal end of the third cylinder to a point intermediate
the ends of the second cylinder, whereby the second cylinder
extends through said second connecting piece into the third
cylinder, the outer surface of the second cylinder and the inner
surface of the second connecting piece together defining an
entrapment zone for solid particles entrained in the incoming
exhaust gases; and
f. spiral guide means of decreasing pitch on the inside wall of the
first cylinder for imparting a spiral motion to incoming exhaust
gases, said spiral guide means comprising approximately 1 percent
of the cross-sectional area of the first cylinder.
Description
This invention relates in particular to a novel spark arrester, but
which also has the more general utility to remove solid particles
entrained in a gas stream. More particularly, it relates to a
device for removing entrained incandescent solid particles (sparks)
from exhaust gases emitted from internal combustion engines.
All internal combustion engines including those of relatively low
horsepower, such as are commonly used on motorcycles, power saws,
small pumps, and the like, must frequently be operated in
locations, such as forests or fields, where accidental fires could
result in extensive property damage and loss of life. It is
characteristic of such engines that the exhaust gases contain
unburned carbon particles which are emitted with the gases in an
incandescent state as sparks. Where these particles are greater
than 0.0232 of an inch in diameter, they constitute a serious fire
hazard because they fall to the ground still sufficiently hot to
ignite any combustible material, such as dry leaves or brush, which
may be about. This is particularly true of moderate to large
motorcycle engines. For this reason, the engines are provided with
devices to remove the sparks from the exhaust gases before they are
released into the atmosphere. A similar problem exists with larger
engines found on heavy equipment such as tractors, bulldozers, and
locomotives.
Prior to this invention, the spark-arresting devices embodied
barriers of various designs, such as stationary louvered vanes (or
"fans" as they are referred to in the art), perforated or slotted
tubes, baffles, or screens. The function of these barriers was to
remove sparks from the exhaust gases by (a) causing the sparks in
the straight-flowing gases to strike such barriers and fall aside
or (b) rotating the flowing gas stream to cause the sparks to be
trapped or destroyed by centrifugal action.
Such spark arresters, which operate on an "impact" principle or a
"centrifugal force" principle, rely on fixed obstructions of
relatively large areas within the arrester housing to remove the
sparks. These fixed obstructions increase the back pressure of the
exhaust system to an extent dependent on their design and number.
Back pressure not only reduces the efficiency of engine
performance, but excessive back pressure can cause permanent engine
damage. Therefore, low back pressure becomes a major consideration
in the design of any spark arrester. However, because a spark
arrester must also have sufficient capacity (defined as the flow in
cubic feet per minute at a back pressure of 1 pound per square
inch) for use with any given engine, such devices are frequently
large and bulky. An additional consideration is the fact that small
internal combustion engines frequently must be operated in varying
positions, as, for example, back-carried engines and those used to
operate hand-carried saws. In such cases, the spark arresters must
not only be small enough to avoid any undue added weight, but they
must also maintain high efficiency regardless of position.
Furthermore, present commercial designs use components that require
centers for structural support and to divert exhaust gases through
spin-producing devices. These center portions are vulnerable to
burnout and vibration failures.
Accordingly, one object of the present invention is to provide a
spark arrester which produces a minimum back pressure. Another
object is to provide such a device which can be made lighter and
smaller than those previously available without reducing its
capacity. A further object is to provide a spark arrester which can
be operated in any position. Still another object is to provide a
small, high capacity spark arrester in which the danger of internal
burnout is minimal.
Other objects will become apparent to those skilled in the art from
the following description.
The spark arrester provided by this invention operates on the
"centrifugal force" principle and utilizes a spiral element within
a housing to control the flow pattern of the exhaust gases. In
general, a preferred embodiment comprises an elongated cylindrical
housing, closed at one end, provided near the open end with an
inlet nozzle for exhaust gases from an internal combustion engine
and a spiral guide on the inside wall of the cylinder advancing
toward the closed end. The spiral guide takes up but a minor
fraction of the cross-sectional area of the cylindrical housing,
thereby introducing a minimal impedance to the flow of gases. Thus,
by avoiding the use of barriers or baffles of large area, it is now
possible to provide a spark arrester of larger capacity relative to
its overall size. These results are made possible by the fact that
entering exhaust gases are caused to flow as a thin layer along the
inner wall of the cylindrical body, as will be described in greater
detail below. This is accomplished by mounting the inlet nozzle so
that, at one point, its inner diameter is tangent to the inner
diameter of the main cylindrical body. The resulting centrifugal
force causes the particles, as well as the gases, to remain close
to the cylinder wall, where they are directed toward the closed end
by the spiral guide. Entrained carbon particles are pulverized at
the closed end, or they can be directed into a trap through a
narrow slot in the main body of the spark arrester. The gases,
however, do not reach the closed end, but reverse their direction
and travel in a spiral path along the center of the cylinder as a
separate stream inside the advancing spiral stream of gases, and
are discharged into the atmosphere through the open end of the
cylinder.
One modification falling within the scope of the invention achieves
similar results without the necessity of closing one end of the
cylinder, thus permitting a straight-through flow of gases. This
device further reduces back pressure; but at the cost of slight
reduced efficiency.
In order that the invention be more readily understood, reference
is made to the following detailed description of the several
embodiments and to the accompanying drawings in which:
FIG. 1 is a simplified schematic illustration of the principle upon
which the present invention is based;
FIG. 2 is a cross section on line 2-2 of FIG. 1, showing the
relative dispositions of the main cylindrical body, inlet nozzle,
and spiral guide, and the relatively unobstructed passageway
through the main cylindrical body;
FIG. 3 is a view, similar to that of FIG. 1, with parts of the main
cylinder broken away to the relative disposition of the internal
members, of a preferred embodiment of the invention;
FIG. 4 is a view of the same embodiment as shown in FIG. 3, also
with parts broken away, but rotated 90.degree. to look down the
longitudinal axis of the gas inlet tube;
FIG. 5 shows a side view of the inlet tube itself, indicating the
"ramp," as will be described in detail below;
FIG. 6 is a side view, with parts broken away to show structure, of
the means for mounting the gas outlet tube;
FIG. 7 is a modification of the preferred embodiment of FIG. 3 in
which a small, axially disposed aspirating tube is, optionally,
provided at the closed end of the cylinder; and
FIG. 8 shows another embodiment of the invention in which both ends
of the cylinder are open and the gases flow through.
As noted above, FIGS. 1 and 2 represent schematic illustrations of
the invention to show the principle upon which it works.
Referring, therefore, to FIGS. 1 and 2, the invention, in general,
comprises a cylinder 1, having one end closed by any suitable cover
means 2. The other end 3 of cylinder 1 is open to the atmosphere.
Secured to the inner wall 4 of cylinder 1, is a spiral guide member
5 of small diameter and which occupies a relatively small fraction
(approximately 1 percent) of the inner cross-sectional area of the
cylinder 1. Spiral guide member 5 is secured in place inside the
cylinder by any suitable means, such as by friction fit, welding,
soldering, or the like. The spiral may also be formed inside wall
by rolling. Spiral guide member 5 begins at a point in from the
open end 3 of cylinder 1 and advances toward closed end 2, ending
some distance short of that end. As a point intermediate the ends
of guide member 5, close to the beginning thereof, an inlet nozzle
6 is secured to cylinder 1. Nozzle 6 serves to introduce exhaust
gases from the exhaust pipe 7 (shown in part) which is connected to
nozzle 6 by any suitable means, such as sleeve 8. Exhaust pipe 7 is
also connected to an internal combustion engine (not shown). In
order to achieve a smooth transition of the flow of exhaust gases
from the nozzle into the cylinder, nozzle 6 is connected to the
cylinder at such an angle that point A of the inner diameter 9 of
the nozzle is tangent to the inner circumference of the cylinder.
It is also necessary to constrict the nozzle by tapering the side
opposite tangent surface 9 to provide a "ramp" 10, as shown in FIG.
2 and also in FIG. 5. Points A and B (FIG. 2) are the plane
projections where the inner surface of nozzle 6 intersects the
inner surface of cylinder 1. In the manner just described, the
linear flow of hot exhaust gases in nozzle 6 is converted to a thin
circular flow along the inner wall of cylinder 1 without
turbulence. Smooth transition of flow is essential to avoid
turbulence so as to maintain the hot gases whirling in a thin layer
along the inner wall of the cylinder. This is essential to prevent
entrained carbon particles from striking the inner cylindrical
surface at an angle that would cause them to bounce off the inner
wall into the path of the exiting gases.
Referring again to FIG. 1, it can be seen that entering hot gases,
together with entrained hot carbon particles flowing in a path
designated by broken arrow 11, are caused by guide member 5 to flow
in a smooth spiral stream along the inner wall of cylinder 1 toward
the closed end. Because of the constriction in nozzle 6, the
exhaust gases and carbon particles enter the cylinder at a
relatively high velocity. Centrifugal force causes the carbon
particles to stay close to the cylinder wall and follow a spiral
path toward closure 2 and impinge on the latter. There the
particles are pulverized by their continued spinning motion and
finally are reduced to smaller than 0.0232 of an inch, at which
size they are no longer considered to be a fire hazard. Because of
their greatly reduced mass, they are expelled with exiting exhaust
gases.
Referring once more to FIG. 1, it will be observed that, upon
entry, the hot particle-containing gases travel toward the closed
end of cylinder 1 in a spiral path indicated by arrows 11. After
proceeding part way down the cavity, the gases reverse their
direction of flow and assume a spiral path 11a, of much smaller
spinning radius, inside spiral stream 11 in the direction of open
end 3 of the cylinder. Since the laws of conservation of momentum
must apply, the angular velocity in the exit direction is greatly
increased by the decreased spinning radius to provide maximum
separating effects capable of producing 100 percent spark arresting
efficiencies.
FIGS. 3 and 4 represent a preferred form of the invention.
As seen in FIGS. 3 and 4, the basic device of FIG. 1 is provided
with a second smaller cylinder or tube insert 13 coaxial with main
cylinder 1. Cylinder 13 is mounted inside a circular, ribbed
orifice ring 14 which has a central, circular opening 15 equal to
the outside diameter of cylinder 13. Details of the structure of
ring 14 are shown in FIG. 6. The outside diameter of ring 14 is the
same as the inside diameter 4 of main cylinder 1. Thus, when
orifice ring 14 is secured in the open end of cylinder 1 by any
suitable means, such as welding, and cylinder 13 is similarly
secured in the circular opening 15 of orifice ring 14, the only
communication between the atmosphere and the inside of main
cylinder 1, is through cylinder 13. The latter extends into
cylinder 1 past the point where nozzle 6 is connected to cylinder
1. As the outside diameter of cylinder 13 is also smaller than the
inside diameter of spiral guide member 5, the resulting structure
comprises the respective coaxial arrangement of main cylinder 1,
spiral guide 5, and inner cylinder 13.
In the embodiment under discussion, spiral guide 5 begins at ring
14 and progresses part way toward the closed end of cylinder 1 to a
point beyond the end of cylinder 13, as shown in FIG. 3.
Gas stream 11 from exhaust pipe 7 follows a path similar to that
indicated in FIG. 1. That is, the gas enters main cylinder 1
tangentially to inner surface 4 and is directed toward the closed
end in a thin spiral stream along the inner surface. As in the
basic design shown in FIG. 1, the stream reverses itself and
follows a coaxially spiral path 11a, of smaller spinning radius,
back toward the exit end through tube 13, from which it exhausts to
the atmosphere through the open end 16 of cylinder 13, leaving
behind a pulverized deposit of carbon particles 12. These particles
when their mass has been sufficiently reduced will be expelled with
exiting exhaust gases. A removable cleanout plug 17 is provided for
inspection of cylinder 1 and removing, if required, accumulated
carbon particles 12. The diameter of tube 13 is, essentially,
dependent on the diameter of opening 15 in ring 14 which is
selected to improve spark arresting efficiency. Ring 14 further
serves to restrict the diameter of main cylinder 1 to provide
optimum flow rate and back pressure characteristics. Although the
tube 13 is optional, its use provides the added advantage of better
noise supression. Noise may be further reduced by adding baffles
(not shown) inside tube 13.
The device just described can optionally be modified to provide for
sucking in a stream of cool air during operation.
Referring to FIG. 7, it is seen that the device is the same as that
of FIG. 3 except that the closure plate 2 is replaced by a plate 18
having a small opening 19 in its center in which there is secured a
short aspirating tube 20. This tube, having a diameter about
one-twelfth of the inside diameter of cylinder 1, is of sufficient
length to extend inward to a point at least inside the last turn of
spiral guide 5 nearest the closed end of main cylinder body 1.
During operation, when the whirling stream of gases 11 reverse
direction and proceed toward the open end as the more rapidly
whirling spiral 11a, the zone of low pressure in the center of the
resulting vortex causes a stream of cool air 21 to be drawn axially
into the cavity of main cylinder 1, thus assisting to cool the hot
exhaust gases and the entrained hot carbon particles. This
aspirated air is picked up by the rapidly swirling stream 11a and
is exhausted together with the latter through tube 13. Furthermore,
stream 11a swirls so rapidly that the pressure in the vortex at
exit end 16 is low enough also to suck cool air 22 into the vortex
at end 16. This air is also picked up by spiral stream 11a and
exhausted. In test runs with this embodiment, the pressure in the
center of the vortex was so low that even solid particles were
sucked in, giving the illusion that these particles were travelling
upstream into the exit end of the apparatus.
In FIG. 8 there is shown still another modification which, although
also operating on the centrifugal force principle, differs in many
important structural features from the apparatus of FIGS. 1, 3, and
7. In this modification the side entrance nozzle is omitted.
Carbon-containing gases enter at one end and leave at the other end
of a generally cylindrical member.
Referring specifically to FIG. 8, exhaust pipe 7 from an internal
combustion engine (not shown) is connected by means of any suitable
sleeve member 8 to the inlet end 23 of a first elongated
cylindrical member 24. The other end 25 of cylinder 24, slightly
constricted in cross section, is joined to the narrower end of a
first conical section 26. The latter is connected at its wider end
to one end of a second, short cylindrical section 27 which is of
greater diameter than cylinder 24 and which is, in turn, joined at
its other end to the wider end of a second conical section 28,
equal in size to conical section 26. A third cylindrical member 29,
of the same diameter as cylinder 24, is joined to the smaller end
of the second conical section 28 and is of such length that it
extends into the second cylindrical member 27. As shown in FIG. 8,
cylinder 24, cone 26, cylinder 27, cone 28, and cylinder 29 are,
successively, joined on a common longitudinal axis.
As in the previously described embodiments, the spark arrester of
FIG. 8 is provided with a spiral guide member 30 of such diameter
that it occupies no more than about 1 percent of the
cross-sectional area of elongated cylinder 24. As in the previously
described embodiments, its purpose is to impart a whirling motion
to the exhaust gases entering the input end 23 of cylinder 24.
However, whereas the spirals of FIGS. 1--4 and 7 can be of uniform
pitch, if desired, because the gases enter the main body of the
arrester in a tangential direction, the gases in this modification
are introduced axially and a spiral motion must be imparted
gradually to avoid turbulence at the inlet. For this reason, the
initial convolution of spiral 30 is of a relatively large pitch
which decreases progressively in the direction of conical section
26. Exhaust gases entering at 23 are given a gentle rotating motion
which increases in velocity as the pitch decreases. At constriction
25 the gases are given an additional axial velocity as they pass
through the constricted area and enter section 26. Centrifugal
force and momentum of the entrained carbon particles cause the
latter to continue in a spiral path of increasing diameter along
the inside walls of cone 26, into cylinder 27 and cone 28, into the
pocket 31 formed by cone 28 and the inward extension 32 of cylinder
29 where they form a partially pulverized deposit 33. The gases,
however, still in a spiral path, pass through cylinder 29 from
which they are exhausted to the atmosphere.
In one specific device constructed according to FIG. 8, the spark
arrester had an overall length of about 20 inches, while cylinder
24 had an inside diameter of about 13/8 inches and was about 10
inches long. Cylindrical portion 27 was 21/2 inches in diameter,
was 6 inches long, and was joined at each end to 23.degree. conical
sections 26 and 28. The inwardly extending portion of cylinder 29
was 4 inches in length, and the pitch of the initial convolution of
spiral 30 was 6 inches. It will be obvious, however, that these
dimensions can be varied proportionately according to the desired
capacity of the spark arrester and its intended use, without
departing from the spirit of the invention.
In the foregoing description of the preferred embodiment of the
apparatus of this invention, the several components were referred
to generally in terms of their function and structural
relationships.
Referring once more to FIGS. 3 and 4, the preferred embodiment of
the invention comprises a main cylinder body, which is closed at
one end and has a reduced opening at the opposite (outlet) end. For
greatest efficiency, it has been found that the inlet nozzle 6
should have a diameter of approximately one-third the diameter of
the main cylinder body 1 and ramp 10 should have a slope of about
4.degree. (the angle .alpha. in FIG. 5). This results in a smooth
transition from linear exhaust flow in the nozzle to a circular
flow in the main cylinder body and eliminates carbon "bounce"
(i.e., rebound of carbon particles from the cylinder walls into the
outlet stream). The nozzle tube itself may have any convenient
length in excess of the ramp length.
For the most efficient operation, the circular opening 15 of
orifice ring 14 and, therefore, the outside diameter of the tube
insert 13 should have a diameter of about half that of the main
cylindrical body 1. Tube 13 should extend inward toward the closed
end of cylindrical body 1 for about half the length of the latter.
The length of the external portion of tube 13 is not critical and
may be cut to suit.
As mentioned previously, the spiral guide member 5 occupies a
relatively small portion of the cross-sectional area of the main
cylindrical body. It has been found that, in embodiments having a
closed end, a single spiral of constant pitch and a cross-sectional
area of about 1 percent of the main body cross section results in
the highest separation efficiency. Optimum efficiency can be
obtained with a spiral guide whose cross-sectional area may be as
small as 0.5 percent of the cross-sectional of cylinder 1. The
spiral guide originates at the point where it contacts orifice ring
14 and extends toward the closed end of cylinder 1 for not more
than 75 percent of the main body axial length. Although a single
turn has been found to be quite effective, it is preferred that the
spiral guide have about 2 to 21/2 turns for best results. Also,
starting from the open (exit) end of the main cylinder body, the
coil origin must precede the nozzle entrance. Although, for best
results, it is preferred to locate the nozzle entrance with the
first turn of the spiral, the distance of the nozzle from the exit
end may be greater.
As already mentioned in the description of the embodiment of FIG.
8, the diameter of the spiral rod or wire 30 should be such as to
occupy no more than about 1 percent of the cross-sectional area of
cylinder 24.
The above-described spark arrester has the advantage that no center
portions are present which can lead to burnout and vibration
failures and which would tend to increase operating back pressures
to undesirable levels.
In comparative tests with commercially available devices of varying
design, the present apparatus exhibited efficiencies of l00 percent
at engine speeds above idle and at extremely high rates of exhaust
flow, permitting its use on weapons loaders.
A nonexclusive, irrevocable, royalty-free license in the invention
herein described, throughout the world for all purposes of the U.S.
Government, with the power to grant sublicenses for such purposes,
is hereby granted to the Government of the United States of
America.
* * * * *