U.S. patent application number 12/269972 was filed with the patent office on 2011-12-01 for sequential injection gas guns for accelerating projectiles.
This patent application is currently assigned to BATTELLE ENERGY ALLIANCE, LLC. Invention is credited to Henry S. Chu, Jeffrey M. Lacy, Stephen R. Novascone.
Application Number | 20110290101 12/269972 |
Document ID | / |
Family ID | 44906800 |
Filed Date | 2011-12-01 |
United States Patent
Application |
20110290101 |
Kind Code |
A1 |
Lacy; Jeffrey M. ; et
al. |
December 1, 2011 |
SEQUENTIAL INJECTION GAS GUNS FOR ACCELERATING PROJECTILES
Abstract
Gas guns and methods for accelerating projectiles through such
gas guns are described. More particularly, gas guns having a first
injection port located proximate a breech end of a barrel and a
second injection port located longitudinally between the first
injection port and a muzzle end of the barrel are described.
Additionally, modular gas guns that include a plurality of modules
are described, wherein each module may include a barrel segment
having one or more longitudinally spaced injection ports. Also,
methods of accelerating a projectile through a gas gun, such as
injecting a first pressurized gas into a barrel through a first
injection port to accelerate the projectile and propel the
projectile down the barrel past a second injection port and
injecting a second pressurized gas into the barrel through the
second injection port after passage of the projectile and to
further accelerate the projectile are described.
Inventors: |
Lacy; Jeffrey M.; (Idaho
Falls, ID) ; Chu; Henry S.; (Idaho Falls, ID)
; Novascone; Stephen R.; (Idaho Falls, ID) |
Assignee: |
BATTELLE ENERGY ALLIANCE,
LLC
Idaho Falls
ID
|
Family ID: |
44906800 |
Appl. No.: |
12/269972 |
Filed: |
November 13, 2008 |
Current U.S.
Class: |
89/8 ;
124/73 |
Current CPC
Class: |
F41B 11/62 20130101 |
Class at
Publication: |
89/8 ;
124/73 |
International
Class: |
F41B 11/06 20060101
F41B011/06; F41F 1/00 20060101 F41F001/00 |
Goverment Interests
GOVERNMENT RIGHTS
[0001] The United States Government has certain rights in this
invention pursuant to Contract No. DE-AC07-05-ID14517 between the
United States Department of Energy and Battelle Energy Alliance,
LLC.
Claims
1. A gas gun for firing a projectile, the gas gun comprising: a
barrel having a bore; at least one gas injection port in
communication with the bore, located proximate a breech end of the
barrel and in communication with a first pressure vessel through a
first valve; at least another gas injection port in communication
with the bore, located longitudinally between the at least one
injection port and a muzzle end of the barrel and in communication
with a at least another pressure vessel through a second valve; a
projectile velocity sensor located between the at least one gas
injection port and the at least another gas injection port; and a
control module in communication with the first valve, the
projectile velocity sensor and the second valve, the control module
comprising a processor configured for control of timing and
duration of opening of the first valve and of the second valve and
to determine a timing and duration of opening of the second valve
responsive to a signal from the projectile velocity sensor.
2. The gas gun of claim 1, wherein: the at least one gas injection
port comprises a first plurality of gas injection ports; and the at
least another gas injection port comprises a second plurality of
gas injection ports.
3. The gas gun of claim 1, further comprising: at least one
reactant injection port located proximate a breech end of the
barrel and selectively couplable to a reactant supply through a
first reactant valve; and at least another reactant injection port
located longitudinally between the at least one injection port and
a muzzle end of the barrel and selectively couplable to a reactant
supply through a second reactant valve.
4. The gas gun of claim 3, further comprising: at least one igniter
positioned proximate the at least one gas injection port and the at
least one reactant injection port, and in communication with the
bore.
5. The gas gun of claim 3, further comprising: at least one igniter
positioned proximate the at least one gas injection port and the at
least one reactant injection port and at least another igniter
positioned proximate the at least another gas injection port and
the at least another reactant injection port, and in communication
with the bore.
6. The gas gun of claim 1, further comprising at least one bore
closure valve located longitudinally between the breech end and the
muzzle end of the barrel.
7. (canceled)
8. The gas gun of claim 1, wherein the barrel comprises a
multi-stage barrel, comprising: a first discrete barrel segment;
and a second discrete barrel segment longitudinally adjacent to the
first discrete barrel segment; wherein each barrel segment has at
least one gas injection port and a valve associated therewith.
9. The gas gun of claim 8, wherein: the first discrete barrel
segment further comprises the at least one reactant injection port
selectively couplable to a reactant supply through a first reactant
valve; and the second discrete barrel segment comprises the at
least another reactant injection port selectively couplable to a
reactant supply through a second reactant valve.
10. The gas gun of claim 8, wherein: the first discrete barrel
segment comprises the projectile velocity sensor; and the second
discrete barrel segment comprises another projectile velocity
sensor.
11. The gas gun of claim 10, wherein: the at least one gas
injection port is located proximate the a breech end of the first
discrete barrel segment; the projectile velocity sensor of the
first discrete barrel segment is located proximate a muzzle end of
the first discrete barrel segment; the at least another gas
injection port is located at a breech end of the second discrete
barrel segment; the another projectile velocity sensor of the
second discrete barrel segment is located proximate a muzzle end of
the second discrete barrel segment; and the muzzle end of the first
discrete barrel segment is coupled to the breech end of the second
discrete barrel segment.
12. The gas gun of claim 1, further comprising a primary pressure
supply selectively couplable to the first pressure vessel and the
second at least another pressure vessel.
13. A modular gas gun for firing a projectile, the modular gas gun
comprising: a plurality of longitudinally adjacent modules, each
module comprising: at least one pressure vessel for containing a
pressurized gas; a barrel segment having a bore; and at least one
injection port positioned and configured for selective fluid
communication with the bore of the barrel segment and a-the
pressure vessel through a valve; and a projectile velocity sensor
located proximate a muzzle end of the barrel segment; wherein the
barrel segment of each module of the plurality of modules is
connected longitudinally to the barrel segment of at least another
module of the plurality of modules and a control module comprising
a processor configured to selectively open each valve and to
process signals from the projectile velocity sensor of each
module.
14. The modular gas gun of claim 13, wherein each module further
comprises: at least another injection port positioned and
configured for selective fluid communication with the bore of the
barrel segment and a reactant supply through a reactant valve.
15. The modular gas gun of claim 14, wherein each module further
comprises: at least one igniter positioned proximate the at least
one injection port and the at least another injection port and in
communication with the bore.
16. The modular gas gun of claim 13, further comprising a bore
closure valve located proximate a muzzle end of the bore of the
barrel segment from which a fired projectile would exit.
17. The modular gas gun of claim 13, wherein the at least one
injection port of each module of the plurality of modules further
comprises a plurality of injection ports, the valve comprises a
plurality of valves, each valve of the plurality of valves being
associated with an injection port of the plurality of injection
ports, and the at least one pressure vessel of each module
comprises a plurality of pressure vessels, each pressure vessel
associated with at least one valve of the plurality of valves.
18. The modular gas gun of claim 17, wherein each injection port of
the plurality of injection ports of each module is located at a
breech end of the barrel segment thereof.
19-21. (canceled)
22. The modular gas gun of claim 17, further comprising a primary
pressure supply in selective communication with each pressure
vessel the plurality of pressure vessels.
23-31. (canceled)
32. The modular gas gun of claim 13, wherein the processor is
further configured for control of timing and duration of a
pressurized gas injection through each valve and to determine a
timing and duration for opening of a pressurized gas injection
through the valve associated with a given barrel segment responsive
to a signal from a projectile velocity sensor of another barrel
segment connected longitudinally to a breech end of the given
barrel segment.
33. The modular gas gun of claim 14, wherein the processor is
further configured to selectively open each reactant valve.
34. The modular gas gun of claim 33, wherein the processor is
further configured for control of timing and duration for opening
of each valve and each reactant valve and to determine a timing and
duration for opening pressurized gas injection of the valve and a
timing and quantity of reactant injection through the reaction
valve associated with a given barrel segment responsive to a signal
from a projectile velocity sensor of another barrel segment
connected longitudinally to a breech end of the given barrel
segment.
35. The gas gun of claim 1, further comprising: a sensor associated
with the at least one bore closure valve for sensing passage of a
projectile through the bore in proximity to the sensor; wherein the
processor is configured to actuate the at least one bore closure
valve responsive to a signal from the sensor upon sensing passage
of a projectile.
36. The modular gas gun of claim 13, further comprising: a bore
closure valve in at least one of the barrel segments; and a sensor
associated with the bore closure valve for sensing passage of a
projectile through the bore of the barrel segment in proximity to
the sensor; wherein the processor is configured to actuate the bore
closure valve responsive to a signal from the sensor upon sensing
passage of a projectile.
Description
TECHNICAL FIELD
[0002] The present invention relates to sequential injection gas
guns and methods for accelerating projectiles through such gas
guns. More particularly, embodiments of the invention relate to gas
guns having a first injection port located proximate a breech end
of a barrel and a second injection port located longitudinally
between the first injection port and a muzzle end of the barrel.
Embodiments of the invention also relate to modular gas guns that
include a plurality of modules, wherein each module may include a
barrel segment having one or more injection ports. Additional
embodiments of the invention include methods of accelerating a
projectile through a gas gun, such as injecting a first pressurized
gas into a barrel through a first injection port to accelerate the
projectile and propel the projectile down the barrel past a second
injection port and injecting a second pressurized gas into the
barrel through the second injection port to further accelerate the
projectile.
BACKGROUND
[0003] The current state of the art of gas guns involves the
compression of a propellant gas, usually a light-gas, such as
helium, prior to introduction thereof into the gun chamber. Because
all propellant gas is introduced through the rear of the gun
chamber at the breech end of the gas gun, relatively high gas
temperatures and peak pressures must be developed to accelerate a
projectile to high velocities. This is because the initial gas
pressure decreases rapidly and cannot be maintained as the
projectile travels down barrel. As such, compression of the
propellant gas generally requires the use of an explosive material,
such as gun powder, acting on a piston.
[0004] When using conventional gas guns, the shot is not controlled
beyond the initiation of a primary stage and if an undesirable
projectile acceleration is occurring within the gun barrel it
cannot be corrected during the shot. As a consequence, obtaining a
desired projectile velocity generally involves trial and error.
[0005] In view of the above, it would be advantageous to provide
improved gas gun devices and methods for accelerating projectiles.
For example, it would be advantageous to provide gas gun devices
and methods offering the acceleration of projectiles to desired
high velocities at lower peak gas pressures and temperatures.
Additionally, it would be advantageous to provide gas gun devices
and methods that offer the ability to control the acceleration of a
projectile as the projectile is accelerated.
SUMMARY OF THE INVENTION
[0006] In one embodiment, a gas gun comprises a barrel having a
bore. The gas gun having at least one injection port in
communication with the bore, located proximate a breech end of the
barrel and in communication with a first pressure vessel through a
first valve. The gas gun additionally having at least another
injection port in communication with the bore, located
longitudinally between the breech end and a muzzle end of the
barrel and in communication with a second pressure vessel through a
second valve.
[0007] In another embodiment, a modular gas gun comprises a
plurality of modules. Each module comprises a barrel segment having
a bore and at least one injection port in communication with the
bore and a pressure vessel through a valve. Additionally, the
barrel segment of each module of the plurality of modules is
configured to connect to the barrel segment of at least one other
module of the plurality of modules.
[0008] In an additional embodiment, a method of accelerating a
projectile through a gas gun comprises positioning a projectile
longitudinally between an injection port and another injection port
within the bore of the barrel. A first pressurized gas volume is
injected into the bore through the first injection port to
accelerate the projectile and propel the projectile down the barrel
past the second injection port. Additionally, a second pressurized
gas volume is injected into the barrel through the second injection
port after passage of the projectile thereby to further accelerate
the projectile and propel the projectile down the barrel toward a
muzzle end of the barrel.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 shows a schematic view of a gas gun according to an
embodiment of the present invention.
[0010] FIG. 2 shows a cross-sectional view of a barrel of a gas gun
according to an embodiment of the present invention.
[0011] FIG. 3 shows a schematic view of a module of the gas gun
shown in FIG. 1.
[0012] FIG. 4 shows a schematic view of another gas gun according
to an additional embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0013] A gas gun 10 is shown in FIG. 1 that includes a barrel 20
with a bore having a plurality of injection ports 30-35 opening
thereinto, each injection port, designated variously at 30-35 in
respective fluid communication with a source of pressurized gas
such as a pressure vessel, designated variously at 40-45 through an
associated valve, designated variously at 50-55. The gas gun 10 may
additionally include a primary pressure supply 60 in selective
communication with and to charge pressure vessels 40-45, one or
more projectile velocity sensors 70-72 and a control module 80.
[0014] The barrel 20 includes a breech end 82, where a projectile
may be positioned in preparation for launching, and a muzzle end
84, where the projectile may exit the barrel 20 upon launching. The
barrel 20, having a plurality of injection ports 30-35, includes a
first injection port 30 and a second injection port 32. The first
injection port 30 is located at, or at least proximate to, the
breech end 82 of the barrel and in fluid communication with a first
pressure vessel 40 through a first valve 50 and the second
injection port 32 is located longitudinally between the breech end
82 and the muzzle end 84 of the barrel 20 and in fluid
communication with a second pressure vessel 42 through a second
valve 52. Additionally, the first injection port 30 may be one of a
first plurality of injection ports 30-31, each of the first
plurality of injection ports 30-31 located at, or at least
proximate, the breech end 82 of the barrel 20. Likewise, the second
injection port 32 may be one of a second plurality of injection
ports 32-33, each of the second plurality of injection ports 32-33
at a longitudinal location between the first plurality of injection
ports 30-31 and the muzzle end 84 of the barrel 20. The barrel 20
may also include any number of additional injection ports 30-35
along its length, such as a third injection port 34 or a third
plurality of injection ports 34-35 at a longitudinal location
between the second plurality of injection ports 32-33 and the
muzzle end 84 of the barrel 20, and so on. As shown in a
cross-sectional view in FIG. 2, a plurality of injection ports 230
may be positioned at a given longitudinal location in a barrel 220
and may be arranged to form an annular array of injection ports
230, such that each injection port 230 of the plurality of
injection ports 230 is located at the same longitudinal position
and at circumferential intervals .theta. in the barrel 220. As
depicted, interval .theta. is 45.degree., but the invention is not
so limited, and a greater or lesser number of injection ports 230
than the eight shown in FIG. 2.
[0015] Referring again to FIG. 1, a plurality of projectile
velocity sensors 70-72 may be distributed along the length of the
barrel 20. A first projectile velocity sensor 70 may be located
between the first injection port 30 and the second injection port
32, a second projectile velocity sensor 71 may be located between
the second injection port 32 and the third injection port 34, and
so on. A final projectile velocity sensor, which may be a third
projectile velocity sensor 72, as shown, may be located proximate
the muzzle end 84 of the barrel 20. The term "projectile velocity
sensor," as used herein, means any sensor that provides a signal
that may be used to determine at least one of: the position of the
projectile in the barrel 20, the time that the projectile is at a
known position in the barrel 20, the velocity of the projectile at
a known position in the barrel 20, and the acceleration of the
projectile at a known position in the barrel 20. Examples of
projectile velocity sensors 70-72 include but are not limited to
proximity sensors, hall effect proximity sensors, contact sensors,
pressure transducers and optical sensors.
[0016] The gas gun 10 may include a control module 80
electronically coupled to, or otherwise in communication with, each
projectile velocity sensor 70-72 and each valve 50-55 of the gas
gun 10. For example, the control module 80 may be configured to
receive signals from each projectile velocity sensor 70-72 and send
signals to each valve 50-55.
[0017] As noted above, the gas gun 10 may also include a primary
pressure supply 60 in selective communication with each pressure
vessel 40-45 of the gas gun 10 to provide a pressurized gas to each
pressure vessel 40-45. For example, each pressure vessel 40-45 may
be a pressure accumulator fluidly coupled to the primary pressure
supply 60, which in turn may be a vessel containing a stored
compressed gas, a gas compressor, such as an air compressor, or a
combination thereof. The pressurized gas may be one of, or a
combination of, a number of gases, including but not limited to
air, carbon dioxide, helium, hydrogen, nitrogen, oxygen and
argon.
[0018] The gas gun 10 may be a multi-stage gas gun, as shown in
FIG. 1, comprising a plurality of modules designated at 90-92 (a
single module 90 shown in FIG. 3). As such, the barrel 20 of the
gas gun may be configured as a multi-stage barrel, including a
plurality of discrete barrel segments 100-102, wherein each module
90-92 includes one of the plurality of barrel segments 100-102.
Each module 90-92 may be substantially identical, and a single
module 90 is described in more detail with reference to FIG. 3.
[0019] With regard to FIG. 3, the barrel segment 100 of module 90
may have a breech end 112 and a muzzle end 114. The barrel segment
may further include a coupler 116 at the breech end 112 and a
coupler 118 at the muzzle end 114. The coupler 114 at the muzzle
end 114 of the barrel segment 100 may be configured to mate with a
coupler 116 at the breech end 112 of another barrel segment. For
example, each barrel segment 100-102 may be configured as a metal
pipe having a pipe flange at each end. With reference to FIG. 1 as
to how the modules 90-92 may be arranged and mutually coupled, the
breech end 112 of a first barrel segment 100 may be coupled to an
end cap 120 to form the breech end 82 of the barrel 20 and a muzzle
end 114 of the first barrel segment 100 may be coupled to the
breech end of the second barrel segment 101. The muzzle end of the
second barrel segment 101 may be coupled to the breech end of a
third barrel segment 102, and so on. The muzzle end of the final
barrel segment, which is the third barrel segment 102 as shown,
remains open to form the muzzle end 84 of the barrel 20.
[0020] Referring again to FIG. 3, the barrel segment 100 may have a
plurality of injection ports 30-31, located at, or at least
proximate, the breech end 112 of the barrel segment 100.
Additionally, the barrel segment 100 may have a projectile velocity
sensor 70 located at, or proximate, its muzzle end 114 or at any
other desired location where its sensing function will not be
compromised by gas injection.
[0021] The module 90 may further include a plurality of valves
50-51 and a plurality of pressure vessels 40-41. Each injection
port 30-31 of the module 90 in fluid communication with the barrel
segment 100 and respectively with a pressure vessel 40-41 through
an associated valve 50-51. As such, each module 90-92 may be a
complete gas gun unit that may be used individually, as a
single-stage gas gun, or in combination with additional modules
90-92, as a multi-stage gas gun.
[0022] As each module 90-92 may be substantially identical, the gas
gun 10 may be assembled with any number of modules 90-92. This may
provide flexibility in the use of the gas gun 10, and allow the
assembly of a gas gun 10 with the precise number of stages required
for a particular application. Additionally, a modular construction
may reduce the manufacturing cost of the gas gun 10 and facilitate
efficient and convenient maintenance and repair of the gas gun 10.
Modules 90-92 may be removed and replaced in a rotation so that
service may be performed on a module 90-92 with minimal down-time
of the gas gun 10.
[0023] Referring again to FIG. 1, a projectile 240 may be
accelerated through the gas gun 10 by a method that comprises the
sequential injection of pressurized gases into the barrel 20. The
projectile 240 may be positioned longitudinally between the first
plurality of injection ports 30-31 and the second plurality of
injection ports 32-33 within the barrel 20, as shown in FIG. 1. A
first pressurized gas volume may be injected into the barrel 20
through the first plurality of injection ports 30-31 to accelerate
the projectile 240 and propel the projectile 240 down the barrel 20
past the second plurality of injection ports 32-33. Then, a second
pressurized gas volume may be injected into the barrel 20 through
the second plurality of injection ports 32-33 to further accelerate
the projectile 240 and propel the projectile 240 down the barrel 20
toward the muzzle end 84 of the barrel 20. The gas injection
process may be repeated as the projectile 240 advances through each
module 90-92 of the gas gun 10.
[0024] Because the pressurized gas is injected into the gas gun 10
sequentially, the acceleration and velocity of the projectile 240
may be controlled as the projectile 240 travels down the barrel 20,
as the amount of gas injected at an injection port 32-35 subsequent
to, or downstream from, injection ports 30-31, may be adjusted
based on data gathered during the shot.
[0025] In one embodiment, the gas gun 10 may be prepared by
supplying a first pressurized gas volume to the first plurality of
pressure vessels 40-41, a second pressurized gas volume to the
second plurality of pressure vessels 42-43 and a third pressurized
gas volume to the third plurality of pressure vessels 44-45 from a
primary pressurized gas supply 60. By way of non-limiting example,
a pressurized gas may be supplied from a primary pressure vessel
containing the pressurized gas, or pressurized air may be supplied
from a gas compressor, such as an air compressor.
[0026] A desired exit velocity for the projectile 240 may be
predetermined prior to firing and the predetermined exit velocity
may be input into the control module 80. The control module 80 may
include a micro-processor which is programmed to calculate a value
representing an ideal amount of pressurized gas to be injected at
each module 90-92, which may also be termed a "stage" of the gas
gun 10, and a value representing an ideal velocity for the
projectile 240 at each of one or more longitudinal positions within
the barrel 20 to achieve the predetermined exit velocity. The
control module 80 may then be used to control the operation of the
gas gun 10 in terms of timing and duration of gas injection through
the valves 50-55. The control module 80 may cause a signal, such as
an electrical voltage, to be sent to the first plurality of valves
50-51 causing the first plurality of valves 50-51 to open and cause
the injection of the first pressurized gas to be directed from the
first plurality of pressure vessels 40-41 into the barrel 20
through the first plurality of valves 50-51 and first plurality of
injection ports 30-31. For example, each valve 50-51 may be a
solenoid injector valve, such as the type used for fuel injection
in internal combustion engines, and the signal may cause a solenoid
of each valve 50-51 to operate and cause the first plurality of
valves 50-51 to open for a specified time.
[0027] The injection of the first pressurized gas behind the
projectile 240 (between the projectile 240 and the breech end 82)
will cause a gas pressure behind the projectile 240 to exceed the
gas pressure in front of the projectile 240, since the barrel 20 is
open to the muzzle end 84, thus causing the projectile 240 to
accelerate down the barrel 20 toward the muzzle end 84 and past
first projectile velocity sensor 70. The first projectile velocity
sensor 70, responsive to detection of the projectile 240 moving
therepast, may send a data signal to the control module 80 as the
projectile 240 travels through the barrel 20 at a longitudinal
position in the barrel 20 prior to reaching the second plurality of
injection ports 32-33. The signal from the first projectile
velocity sensor 70 may be used by the micro-processor to calculate
a value that represents the actual velocity of the projectile 240
at the longitudinal position, which may then be compared to the
value that represents the ideal velocity for the projectile 240 at
that longitudinal position. This comparison may be used to
determine a new value representing the timing and amount of
pressurized gas to be injected through the second plurality of
injection ports 32-33. The control module 80 may then send a signal
to the second plurality of valves 52-53 based on the new value to
cause the second plurality of valves 52-53 to open at a particular
time for a specified amount of time and cause the injection of the
second pressurized gas volume to be directed from the second
plurality of pressure vessels 42-43 into the barrel 20 through the
second plurality of valves 52-53 and second plurality of injection
ports 32-33. The injection of the second pressurized gas volume
behind the projectile 240 will cause a second increase in gas
pressure behind the projectile 240 and further accelerate the
projectile 240 toward the muzzle end 84 of the barrel 20. These
acts may be further repeated at each module 90-92 or stage of the
gas gun 10, such that the acceleration and velocity of the
projectile 240 may be controlled as it travels through the barrel
20 based on a feedback loop comprising signals received by the
control module 80 from each projectile velocity sensor 70-72 and
signals sent from the control module 80 to each valve 50-55.
[0028] In addition to controlling the acceleration and velocity of
the projectile 240 as it travels through the barrel 20, embodiments
of the method of the invention may be used to reduce peak gas
pressures, which may be harmful to payloads. Peak gas pressures may
be reduced because the pressurized gas is injected in stages,
instead of injected only through the breech end 82 of the barrel
20. Reducing the peak pressure may enable the acceleration of
relatively fragile projectiles in the gas gun 10, which projectiles
would be damaged by relatively high peak pressures.
[0029] Another benefit of embodiments of the invention may be the
realization of higher projectile velocities. The speed of a
pressure wave in a working fluid, such as a pressurized gas in a
gas gun 10, is limited to the speed of sound in the working fluid.
Consequently, a pressure wave originating at the breech end of a
conventional gas gun may not travel down the barrel to a location
as quickly as pressurized gas may be directly injected at that same
location in accordance with embodiments of the invention. Thus,
each location of gas injection can be used to boost projectile
acceleration at a faster rate than would otherwise be possible with
only a single injection site proximate the breech end of a single
stage gas gun.
[0030] Sequential injection methods may also enable the use of
gases supporting a relatively low speed of sound. This capability
may allow the use of readily available gases that support
relatively low speeds of sound, such as air and carbon dioxide, to
obtain projectile velocities that conventionally require the use of
gases that support relatively high speeds of sound, such as helium
and hydrogen.
[0031] In additional embodiments of the invention, sequential
injection methods may be used with combustion gases, or other
chemical reactants.
[0032] An additional embodiment of a gas gun 300 according to the
present invention is shown in FIG. 4. The gas gun 300 shown in FIG.
4 may be arranged in a manner similar to the gas gun 10 shown in
FIG. 1. The gas gun 300 may include a barrel 20, proximity sensors
70-72 and a control module 80, similar to the gas gun 10 of FIG. 1.
However, the gas gun 300 differs from the gas gun 10 somewhat in
its configuration, as the gas gun 300 includes both a primary
pressure supply 310 and a reactant supply 320. The inclusion of a
separate primary pressure supply 310 and reactant supply 320 allow
the introduction of a pressurized gas and a reactant that may
combust, or react chemically, within each stage of the gas gun 300.
The gas gun 300 may also include a first igniter 330, located
proximate the first plurality of injection ports, and additionally
include a second igniter 331 and a third igniter 332 located
proximate the second and third plurality of injection ports 32-33
and 34-35 respectively, each igniter 330-332 in communication with
the bore of the barrel 20. For example, the igniters 330-332 may be
electronic igniters, such as spark plugs or piezoelectric igniters,
which may form an electric arc within the bore to initiate a
chemical reaction therein. Optionally, a plurality of igniters may
be provided proximate each plurality of injection ports 30-35.
[0033] Optionally, the gas gun 300 may include one or more bore
closure valves 340-341 located along the length of the barrel. For
example, a first bore closure valve 340 may be located proximate
the muzzle end 114 of the first barrel segment 100. Additional bore
closure valves, such as a second bore closure valve 341, may be
similarly situated in other barrel segments, such as the barrel
segment 101.
[0034] The primary pressure supply 310 of the gas gun 300 may
supply a pressurized gas to one or more pressure vessels at each
stage of the gas gun 300, such as pressure vessel 40 of the first
plurality of pressure vessels 40-41, pressure vessel 42 of the
second plurality of pressure vessels 42-43, and pressure vessel 44
of the third plurality of pressure vessels 44-45. Additionally, the
reactant supply 320 may provide a reactant, such as a reactant gas,
to one or more pressure vessels at each stage of the gas gun 300,
such as pressure vessel 41 of the first plurality of pressure
vessels 40-41, pressure vessel 43 of the second plurality of
pressure vessels 42-43, and pressure vessel 45 of the third
plurality of pressure vessels 44-45.
[0035] In additional embodiments, the reactant supply may deliver a
liquid reactant directly to reactant valves, such as valves 52, 53
and 55, through injection lines. For example, a liquid reactant may
be delivered from a pump and/or pressure vessel to valves 52, 53
and 55 through an injection line and atomized within the bore of
the barrel 20 as it is injected through one of the valves 52, 53
and 55.
[0036] The primary pressure supply 310 may supply a pressurized gas
that may react chemically with a reactant. For example, the primary
pressure supply 310 may supply an oxidizer, such as air, oxygen,
nitrous oxide, or a combination thereof. The reactant supply 320
may supply a gas and/or a liquid that may, under appropriate
stimulus, such as the aforementioned electrical arc, be caused to
react with the pressurized gas supplied by the primary pressure
supply 310. For example, the reactant supply 320 may supply a
combustible gas, such as one or more of methane, propane, butane
and acetylene. In another example, the reactant supply 320 may
supply a combustible liquid, such as one ore more of gasoline,
kerosene, methanol and ethanol. In additional embodiments, the
reactant supply 320 may supply a solid particulate reactant
suspended in a gas or a liquid.
[0037] A projectile may be accelerated through the gas gun 300 by a
method that comprises injections of a pressurized gas and a
reactant into the barrel 20, and the initiation of a chemical
reaction of the pressurized gas and reactant, such as combustion.
The projectile may be positioned longitudinally between the first
plurality of injection ports 30-31 and the second plurality of
injection ports 32-33 within the barrel 20. A first pressurized gas
volume may be injected into the barrel 20 through at least one
injection port of the first plurality of injection ports 30-31,
such as injection port 30, and a first reactant quantity may be
injected through at least another injection port of the first
plurality of injection ports 30-31, such as injection port 31. A
chemical reaction of the first pressurized gas volume and first
reactant quantity may be initiated by the first igniter 330, which
will cause an increase in pressure behind the projectile to
accelerate the projectile and propel the projectile down the barrel
20 past the second plurality of injection ports 32-33. Then, a
second pressurized gas volume may be injected into the barrel 20
through at least one injection port of the second plurality of
injection ports 32-33, such as injection port 32, and a second
reactant quantity may be injected through at least another
injection port of the second plurality of injection ports 32-33,
such as injection port 33. A chemical reaction of the second
pressurized gas volume and second reactant quantity may be
initiated by the second igniter 331, which will cause another
increase in pressure behind the projectile to further accelerate
the projectile and propel the projectile down the barrel 20 toward
the muzzle end 84 of the barrel 20. The gas/reactant injection and
ignition process may be repeated as the projectile advances through
each module 90-92 of the gas gun 300.
[0038] In additional embodiments, one or more igniters, such as the
first igniter 330, may be used to initiate an initial chemical
reaction, and subsequently injected pressurized gas volumes and
reactant quantities may be caused to react by the flame front or
reaction heat provided by the initial and/or subsequent chemical
reaction without the assistance of additional igniters, such as
igniters 331-332.
[0039] In yet additional embodiments, a relatively reactive
pressurized gas volume and reactant quantity may be cooperatively
formulated to react spontaneously upon mixing within the barrel 20
and may not require an igniter 330-332 to initiate a chemical
reaction.
[0040] Because the pressurized gas volumes and reactant quantities
are both injected into the gas gun 300 and caused to react at
sequential stages, the acceleration and velocity of the projectile
may be controlled as the projectile travels down the barrel 20, as
the amount of gas and/or reactant injected at an injection port
32-35 subsequent to, or downstream from, injection ports 30-31, may
be adjusted based on data gathered during the shot.
[0041] The control module 80 may control the operation of the gas
gun 300, shown in FIG. 4, in a similar manner as discussed with
reference to gas gun 10, shown in FIG. 1. The control module may
control the operation of the valves 50-55 based on a predetermined
velocity and feedback received from the projectile velocity sensors
70-72. However, in addition to controlling the timing and duration
of a pressurized gas injection through valves 50, 52 and 54, the
module may control the timing and quantity of a reactant injection
through valves 51, 53 and 55. Additionally, the control module 80
may control the timing of the operation of one or more igniters
330-332.
[0042] As mentioned above, embodiments of the invention may include
optional bore closure valves 340-341, as shown in FIG. 4, and may
operate using sequential pressurized gas volume injections, as
described in reference to the gas gun 10 shown in FIG. 1, or
injections of pressurized gas volumes and reactant quantities, as
described in reference to the gas gun 300 of FIG. 4. The bore
closure valves 340-341 may be located at various locations along
the barrel 20, as previously described, and may be configured to
allow the passage of the projectile past the bore closure valve
340-341 when open, and block or restrict gas flow past the bore
closure valve 340-341 when closed. For example, the closure valves
340-341 may include a ball type valve and/or a gate type valve.
[0043] Initially the bore closure valves 340-341 may be open and
allow passage of the projectile as it is accelerated through the
barrel 20. Substantially immediately after the projectile has
passed the first bore closure valve 340, the first bore closure
valve 340 may be closed. For example, the control module 80 may
cause the first bore valve 340 to close by via an
electro-mechanical actuator that may include a solenoid and/or a
motor. The closure of the first bore valve 340 may be initiated by
a sensor 70-72 upstream or downstream thereof which senses passage
of a projectile, and be used to reduce the open bore volume behind
the projectile to facilitate an increase in pressure behind the
projectile caused by the injection through the second plurality of
injection ports 32-33, and optionally a subsequent chemical
reaction. After the projectile proceeds down the barrel 20 past the
second bore closure valve 341, the second bore closure valve 341
may be caused to close, and so on.
[0044] In light of the above disclosure it will be appreciated that
the devices and methods depicted and described herein enable the
effective acceleration of projectiles to a specified velocity for
experimental and laboratory use. In addition, it is contemplated
that the invention may have additional utility in a variety of
scales for a variety of other applications, such as military and
aerospace applications. For example, the described devices and
methods may be useful for launching projectiles in the form of
warheads, missiles, munitions or other military ordnance.
Additionally, the described devices and methods may be useful for
launching aircraft, spacecraft, satellites or other devices into
the atmosphere, into a planetary-orbit, or into outer space.
[0045] While specific embodiments of the invention have been shown
by way of example in the drawings and have been described in detail
herein, the invention is not limited to the particular forms
disclosed. Rather, the invention includes all modifications,
equivalents, and alternatives falling within the scope of the
invention as defined by the following appended claims and their
legal equivalents.
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