US 7157802 B2
An electrical power source is described. The electrical power source derives input power from a compressed gas which is fed into a transducer, generating electrical power. The compressed gas may be delivered to the unit by several means including manual pumps, thermal, chemical, or ammunition based sources, or connection to pressurized canisters. Optional power converting and feedback circuits and pneumatic valves serve to convert the raw output power into useful AC and DC output voltages, and to match the rate of power delivery to the applied electrical load.
1. An electrical power source comprising:
an inflator for compressing gas into the tank, the inflator configured for operation when unconnected to external electrical power;
a transducer for pneumatically converting gas from the tank to electrical power;
electronics operable to derive a feedback signal dependent on an electrical load driven by the electrical power source; and
a pneumatic valve responsive to the feedback signal to operably adjust flow of the gas to the transducer.
2. The electrical power source of
3. The electrical power source of
4. The electrical power source of
5. The electrical power source of
6. The electrical power source of
7. The electrical power source of
8. The electrical power source of
9. The electrical power source of
10. An electrical power source comprising:
a first tank;
an inflator for compressing gas into the first tank, the inflator configured for operation when unconnected to external electrical power, the inflator having a connection to a second tank containing compressed gas; and
a transducer for pneumatically converting gas from the tank to electrical power.
11. The electrical power source of
12. The electrical power source of
13. The electrical power source of
14. The electrical power source of
15. The electrical power source of
16. The electrical power source of
17. The power source of
18. The power source of
19. The power source of
20. The electrical power source of
This application claims priority to U.S. provisional application Ser. No. 60/511,963 filed 16 Oct. 2003, which is hereby incorporated by reference.
This invention was made in part with the support of the U.S. Government; the U.S. Government has certain rights in this invention as provided for by the terms of Grant #N00178-03-C-3093 awarded by the U.S. Navy.
Numerous applications exist for electrical power sources (e.g., a battery). One of these applications is within the field of emergency communications. Emergency communications are often required under less than ideal conditions, such as during natural and man-made disasters. Interruption of normal power sources (e.g., household power), and the importance of communicating quickly, can create situations in which power sources can be extremely valuable, for example the use of batteries to power radio or cellular communications during emergency situations.
Another application for electrical power sources occurs in modern military operations, which are increasingly reliant on portable electrical power sources for communication, night vision, and navigation systems (for example navigation systems employing the Global Positioning System). In the event that supply lines are cut off, battery power for these systems may be drained quickly, and access to electrical power can mean the difference between life and death of a soldier.
There are several known approaches to storing mechanical energy for electrical power supply. For small appliance operation, these include wind-up springs, flywheels and batteries. Wind-up springs are typical of the radio sets used in WWII, in which the operator winds a spring that slowly releases energy while the radio is used. Flywheels are often seen in commercial hand-operated flashlights, in which the flywheel is brought up to speed prior to operating the flashlight. The battery approach is exemplified in the automobile starter system, where a battery is used to store energy sufficient to crank over the motor. However, batteries are generally heavy in comparison to the output power they can produce, and can provide only a limited amount of power before they must be recharged or replaced. Other known approaches utilize gravitational potential energy, such as the wind-up clock that employs lifted weights; however, such devices do not lend themselves to light weight or portability due to their use of an elevated mass in a particular orientation.
In one embodiment, an electrical power source is provided. A manual pump (e.g., a foot pump) compresses gas (e.g., air) into a tank. A transducer pneumatically converts gas from the tank to electrical power, for example to regulate a desired output voltage usable by external devices (and/or to recharge batteries).
In one embodiment, a method of producing electrical power is provided, including: compressing gas for storage in a tank, and pneumatically converting gas from the tank into electrical power.
In one illustrative embodiment, electrical outlet 22 triggers pneumatic control valve 41 through a mechanical linkage 40 such that gas 5 releases from tank 11 and flows to transducer 12 when an electrical appliance plugs into electrical outlet 22.
In another embodiment, a feedback signal 30 is generated by electronics 29 and communicated to a pneumatic control valve 31. The feedback signal directs pneumatic control valve 31 to increase flow to transducer 12 when the AC or DC output voltage is less than a desirable voltage range, and to decrease flow to transducer 12 when the AC or DC output voltage exceeds the desirable voltage range. The action of the feedback signal 30 and pneumatic valve 31 may serve the purpose of matching the gas flow into transducer 12 to the output power required, to avoid overpowering or underpowering the attached electrical appliance. Feedback signal 30 and pneumatic valve 31 also serve the purpose of conserving compressed gas 5 (and its inherent stored energy) for use only as needed.
In embodiments using pneumatic control valves 31 or 41, another pneumatic control valve 50 may be used. Pneumatic control valve 50 is normally closed, but may be opened by pushing a button 52, allowing a flow of compressed gas 5 into transducer 12 to begin power generation. This feature serves to override the closure of pneumatic control valve 31 due to initial lack of power to electronics 29, and to override the closure of pneumatic valve 41, allowing power generation even if no appliance is plugged into electrical outlet 22.
Electronics 20 may also detect when the power source is incapable of delivering voltage that is within the desirable voltage range. When this occurs, electronics 20 may disconnect the AC or DC output voltage from output line 21.
Step 506 may also include the step of regulating the electrical power to a desired AC or DC output voltage. By way of example, the output voltage may be regulated to 120V or 12V. Plug-in step-down DC-DC converters may attach thereto to generate other voltages. Step 504 may occur through in response to a particular action, for example by plugging an electronic device into an outlet 22 (which triggers a mechanical or electrical valve that opens a pathway from compressed gas 5 to transducer 12). Optionally, a button may be included with a power source which, when selected, opens airflow between tank 11 and transducer 12. The compressing step 502 may also occur through one of several methods, including any of the following: operating a manual pump; using a chemical generator; using an ignited chemical in a pressure vessel; reacting a mixture of two or more chemicals in a pressure vessel.; using a detonated gas charge; using an ammunition based pressure generator; and using an externally heated pressure vessel.
The systems and methods described hereinabove may thus provide certain advantages. For example, the power source may form a modular unit with modular replacement components. The storage tank may be any known air-tight canister (the canister used with paint ball guns is for example suitable) or tubing (for example fire hose that may be rolled up and easily carried). The transducer may also be a modular replacement component, such as an air motor and generator; and the air motor and generator may share a common shaft. Alternatively, the transducer may comprise a shunt wound motor, with windings on rotor and stator. Even the output elements may be modular, for example including power conditioning plugs or adaptors (e.g., to step down voltage from 120V to 12V or other desired voltage), or battery chargers. In other embodiments, the output elements may be integrated into a common interface. Further, the inflator may be modular, for example comprising a foot pump, bicycle pump, or even shoes that connect with a fire hose “tank” so that simply the act of walking pressurizes air in the tank. Pressurization of the tank may also occur through chemical action, or through operation of an ammunition round such as a bullet or a shotgun shell, such that when the round is fired, the gas pressurizes in the tank. Moreover, the modular power source as described herein may connect to existing pressurization sources so as to provide output voltages; in which case, the tank or pump may be discarded for that immediate application.
Changes may be made in the above methods and systems without departing from the scope hereof. It should thus be noted that that the matter contained in the above description or shown in the accompanying drawings should be interpreted as illustrative and not in a limiting sense. The following claims are intended to cover all generic and specific features described herein, as well as all statements of the scope of the present method and system, which, as a matter of language, might be said to fall there between.