US20040146408A1 - Portable air compressor/tank device - Google Patents

Abstract

A portable, low cost air supply device for accumulating and dispensing compressed air converted from photovoltaic energy. The device includes one or more photovoltaic cells, a capacitor, an electronic trigger device, a solenoid, a valve manifold, a reservoir, and a device for dispensing accumulated air. The photovoltaic cell(s) charge the small, low cost capacitor. When saturated, the capacitor is triggered by a solid-state device to discharge the electrical charge to a solenoid. The energized solenoid then extends its plunger into a hole in the valve manifold, compressing air into the manifold. The compressed air moves past a check valve, and into a storage reservoir. The solenoid rapidly de-energizes, the plunger retracts, and the solenoid is now ready for another compression stroke.

Description

• This application claims the benefits of provisional application Serial No. 60/426,294 filed Nov. 14, 2002.[0001]
FILED OF THE INVENTION
• The invention relates to a portable, low cost air supply device for accumulating and dispensing compressed air and powered by photovoltaic energy.[0002]
BACKGROUND OF THE INVENTION
• U.S. Pat. No. 6,367,259 describes an air compressor system that includes a rotary induction motor, motor control circuitry, expensive large capacitors, and associated packaging. To date, air compressor systems that accumulate energy from photovoltaics have been made up of conglomerations of large static devices, working together and coordinated by complicated control circuitry and sensors. These systems are commonly formatted as banks of batteries or banks of large expensive capacitors. Such storage devices drive induction motors, which then finally drive compressors.[0003]
SUMMARY OF THE INVENTION
• An embodiment of the invention provides an air supply device and method that accumulate and distribute compressed air without the use of the large static devices referenced above, that can be hand carried to the point of use with a size scale easily applied by the end user, and that eliminates the need for a rotary induction motor, motor control circuitry, expensive large capacitors, and associated packaging.[0004]
• One illustrative embodiment of the invention involves a self-replenishing, portable air supply device that includes an air reservoir tank and one or more photovoltaic cells disposed exterior of the air reservoir tank. The photovoltaic cell(s) provide(s) electrical power to a capacitor, which intermittently discharges to a solenoid, which then mechanically compresses air into the reservoir tank. In a preferred embodiment of the invention, the capacitor and solenoid and other related components are located inside the air reservoir tank.[0005]
• The invention optionally provides on the air reservoir tank one or more of a flashlight, a self-retracting hose reel, a hose pressure indicating gauge/LCD readout, a manually activated valve to dispense compressed air, and a connector to secure the portable reservoir tank in a location of use (i.e. pick-up truck bed). The invention also envisions optionally providing one or more remote-mounted photovoltaic cell(s) to allow the air supply device to serve as an imbedded power unit within a larger system.[0006]
• The invention is advantageous to improve the manufacturability and affordability of a portable air compressor system by virtue of reduced number of component parts, simplified integral packaging (placing sensitive components inside the air reservoir tank), and enabling the use of a very small, and exponentially cheaper capacitor. Other advantages of the invention will become more readily apparent from the following description taken with the following drawings.[0007]
DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a schematic view of an air supply device pursuant to an embodiment of the invention shown for use in inflating a pick-up truck tire.[0008]
• FIG. 2 is a perspective view of an air supply device to an embodiment of the invention with the air reservoir tank partially broken away to show the portion of the solenoid pump assembly residing inside the tank.[0009]
• FIG. 2A is an enlarged view of the solenoid pump assembly.[0010]
• FIG. 3 is a sectional view of the solenoid pump assembly and air reservoir tank wall, depicting the pneumatic circuit. The circuit board B and capacitor and trigger device thereon are shown schematically for convenience.[0011]
• FIG. 4 is a schematic view showing the photovoltaic cells and related electronic components relative to the air reservoir tank, depicting the electrical circuit.[0012]
• FIG. 4A is an enlarged view of the electrical trigger device of FIG. 4.[0013]
• FIG. 5 is a perspective view of the air supply device showing the air reservoir tank having thereon a flashlight, a self-retracting hose reel, a hose pressure indicating gauge/LCD readout, a manually activated valve to dispense compressed air, and a locking lug to secure the portable reservoir tank in locations of use (i.e. pick-up truck bed).[0014]
• FIG. 6 is a perspective view showing the air supply device having a lug for mounting the air supply device on the bed of pick-up truck.[0015]
• FIG. 7 is an elevational view of the air supply device having a manual trigger thereon actuated to dispense compressed air from the air reservoir tank.[0016]
• FIG. 7A is an enlarged view of the manual trigger.[0017]
DESCRIPTION OF THE INVENTION
• Referring to FIG. 1, an air supply device and method pursuant to an illustrative embodiment of the invention comprises an[0018]air reservoir tank1 of conventional fabrication (mild steel, or aluminum, or plastic composite construction) with anintegral carry handle21 and attached supportingfeet20 for resting on a horizontal surface. Apipe nipple2, FIG. 2 is disposed on and extends through and into theair reservoir tank1. Asolenoid pump assembly19 is configured as a plug received in thepipe nipple2, with certain mechanical and electrical circuitry of the solenoid pump assembly disposed in, and totally enclosed within, theair reservoir tank1 as will become apparent below.
• On the exterior surface of[0019]tank1 is/are mounted one or more photovoltaic cell(s)14. The energy from the photovoltaic cell(s)14 is used to charge intermittentlysolenoid8 of thesolenoid pump assembly19 using an electrical circuit shown in FIG. 4. Solenoid8 and its enclosedplunger7 reside in thetank1, FIG. 3, and are configured to function as an air compressor pump when combined withvalve manifold11. Thesolenoid8 includes a housing with a threaded or flanged end that is threaded or bolted onto thevalve manifold11 to join them together as shown in FIG. 3. The combination of thesolenoid8 andvalve manifold11 is referred to as thesolenoid pump assembly19. On it's retract stroke, plunger7, functioning as a piston, draws atmospheric air through the externally protrudingtank valve3 of thesolenoid pump assembly19. Once thesolenoid8 is energized, plunger7 advances, compressing air past spring-biased check valve13 and into theair reservoir tank1. Thesolenoid8 can be a commercially available solenoid, such as Ledex brand size 3EC model available from Saia-Burgess, Inc.
• The[0020]valve manifold11 has attached, or built integral to it, devices including 1) a pressure relief valve6, to preventtank1 over pressurization; and 2) a Schraderstyle tank valve3, functioning as an air intake, back flow check valve, and allowing the filling oftank1 from an external compressed air source. Further devices attached or built integral tomanifold block11 includegauge port5 for mounting apressure indicator27 for gauging discharge pressure;discharge hose connector12; andoptional discharge valve10 for manually controlled dispensing of compressed air.Discharge hose4 is a flexible tube connected todischarge hose connector12.Discharge hose4 is used for dispensing compressed air from withintank1, and can be configured as a static shape, coiled, or combined with an optional self-retractinghose reel23 as shown in FIG. 5.
• An[0021]electrical trigger device16, FIG. 4, is provided and determines when there is enough electrical charge (energy) stored incapacitor15 as an electrical power storage device to energizesolenoid8. Capacitor15 will be of low cost and small size, generally in the 2200 micro Farad size range. Thetrigger device16 in its essential embodiment includes a diode16aand transistor16barranged as shown in FIG. 4A that function together to detect a fullycharged capacitor15, distribute this stored energy tosolenoid8, and then reset the circuit so that the energy supplied by photovoltaic cell(s)14 can rechargecapacitor15 to repeat the cycle. Thecapacitor15trigger device16 and other electrical components are mounted on a circuit board B located inside thetank1, FIG. 2. The circuit board is fastened by a U-shaped bracket to the solenoid housing as shown in FIG. 3. If it is desired to give an indication external of thetank1 that thesolenoid8 is energized,LED17 can be optionally installed in the circuit as shown in FIG. 4. A currentlimiting device18, which may comprise a resistor, may be required in the circuit dependent on the current handling characteristics of photovoltaic cell(s)14.
• The air supply device also may contain the following optional features: (a) a[0022]pressure switch28 to shunt excess electrical potential from photovoltaic cell(s)14 to the charging of arechargeable flashlight22, FIG. 5, that is disposed on, and preferably built integral to thecarry handle21 such that the flashlight body functions as the carry handle fortank1; (b) an AC/DC or DC/DC power adapter29 for powering the air supply device from an external electrical source; (c) a C-shaped (or other shaped)strap connector24, FIG. 6, which is fastened on theair reservoir tank1 and which receives and is lockable onto anelongated male bracket25 attached to a truck bed, FIG. 6 (or other structure) when the air supply device is positioned on the truck bed proximate the front wall thereof so as to prevent the theft of the device, thebracket25 having a punched or otherwise-formed hole to receive a common padlock in a manner that also passes through thestrap connector24 to lock the connector and the bracket together; (d) air dispensingvalve10 movable relative to valve seat10aand configured as a manually depressed button, or activated by alever30 disposed on acarrying handle21 attached totank1, FIG. 7, such that when thelever30 is manually squeezed, the lever rocks onpivot pin31 in a manner to depress air dispensingvalve10, which than opens relative to seat10aand supplies compressed air to thedischarge hose4; and (e) apressure gauge26, FIG. 5, for indicating tank air pressure. In an alternative embodiment of the invention, thedischarge hose connector12 can be omitted and replaced with hard piping so that the air supply device can be used as an integral power supply subcomponent to a larger system. Theair reservoir tank1 may or may not require customizing to conform within the encompassing larger system and may or may not require the remote location of thephotovoltaic cells14 as a power source. Still further, thesolenoid pump assembly19 alternatively may be mounted or disposed externally to anair reservoir tank1 as either a retrofit to an existing passive air tank, or as an alternative way to construct an air supply device pursuant to another embodiment of the invention.
• In operation, photovoltaic cell(s)[0023]14 produce electric current through exposure to any incident light energy. The electric charge is stored incapacitor15. Oncecapacitor15 achieves a charge sufficient enough to overcome the breakdown voltage of thetrigger device16, the electrical charge is then free to pass through to the coil ofsolenoid8, FIG. 4, to power the solenoid. Anenergized solenoid8 creates an electromagnetic flux passing through the center of thesolenoid8.Plunger7, which is located in the center ofsolenoid8, resists the electromagnetic flux, which causesplunger7 to thrust rapidly upwards out ofsolenoid8. The air on the leading surface ofplunger7 is compressed throughcheck valve13 and into theair reservoir tank1. The charge in the capacitor is diminished rapidly andplunger7 self centers back intosolenoid8 as the flux relaxes. Gravity helps theplunger7 retract into the solenoid coil in vertical plunger orientations as shown in FIG. 3. In other plunger orientations or to speed up retraction of theplunger7, a retractspring32 optionally may be provided as shown in FIG. 3 to bias the plunger to this end. Additional plunger retraction speed can be achieved by modifying thetrigger device16 to not just relax the current flow insolenoid8, but to reverse the current flow to thereby forcibly retract theplunger7 within thesolenoid8. The withdrawal ofplunger7 creates a slight low-pressure area within the cavity ofvalve manifold11. This vacuum is relieved by atmospheric air pressure overcoming the valve stem seating pressure in Schraderstyle tank valve3 and enters thevalve manifold11 internal cavity. The air supply device is now ready for another cycle. The frequency of cycles will depend on available light, but will most likely not exceed 2 cycles per second at maximum sunlight due to the duty cycle limitations of most commonly commercially available solenoids.
• Once the[0024]air reservoir tank1 is at the maximum designed pressure, the backpressure from the compressed air will counterbalance the thrust force ofplunger7, and theplunger7 will no longer be able to further compress air into the tank.Plunger7 will be stalled, withcapacitor15 continuing to dissipate energy intosolenoid8. This “self maintaining” mode can be held indefinitely until gradual leakage reduces air volume to the point where theplunger7 can move forward and replace the escaped air. Alternatively, apressure switch28 can detect a full tank of air, and disconnect the solenoid driving circuit shown in FIG. 4. Thepressure switch28 can then optionally redirect the electric potential to charging aflashlight22, which would be beneficial for nighttime use of the invention. Theflashlight22 may be built into thecarry handle21 oftank1 so as to prevent loss/theft of the light. Theflashlight22 will shine across and illuminate thepressure indicator27 atgauge port5 as well as illuminate whatever equipment is receiving the compressed air being dispensed from the air supply device.
• Although certain illustrative embodiments of the invention have been described herein, those skilled in the art will appreciate that the invention is not limited thereto and that changes, modifications and the like can be made thereto without departing from the spirit and scope of the invention as set forth in the appended claims.[0025]

Claims (22)

I claim:

1. A self replenishing, portable air supply device, comprising an air reservoir tank, one or more photovoltaic cells exterior of the air reservoir tank, a capacitor for receiving electrical power from the one or more photovoltaic cells and intermittently discharging to a solenoid, said solenoid then mechanically compressing air into the air reservoir tank.

2. Air supply device ofclaim 1 wherein the capacitor and solenoid are disposed inside the air reservoir tank.

3. Air supply device ofclaim 1 including a flashlight disposed on the air reservoir tank.

4. Air supply device ofclaim 1 including a self-retracting hose reel disposed on the air reservoir tank.

5. Air supply device ofclaim 1 including a hose pressure indicating gauge with pressure readout disposed on the air reservoir tank.

6. Air supply device ofclaim 1 including a manually activated valve disposed on the air reservoir tank to dispense compressed air.

7. Air supply device ofclaim 1 including a connector to secure the air reservoir tank in a location of use.

8. Air supply device ofclaim 7 wherein the connector secures the air supply device on a pick-up truck bed.

9. Air supply device ofclaim 1 including a one or more photovoltaic cells for location remote from the air reservoir tank.

10. A self replenishing, portable air supply device, comprising an air reservoir tank and one or more photovoltaic cells exterior of the air reservoir tank to power an air compressor pump which resides inside the tank.

11. A self replenishing, portable air supply device, comprising an air reservoir tank, one or more photovoltaic cells exterior of the air reservoir tank to provide electrical power to a power storage device, which intermittently provides electrical power to an air compressor pump.

12. The air supply device ofclaim 11 wherein the air compressor pump receives atmospheric air to be compressed via a check valve on the tank.

13. A method of supplying compressed air, comprising generating photovoltaic electrical power using light exterior of an air reservoir tank, storing the electrical power, and intermittently providing the stored power to an air compressor pump to pressurize the air reservoir tank.

14. The method ofclaim 12 including intermittently providing the stored power to an air compressor pump inside the air reservoir tank.

15. An air reservoir tank having a manually activated air dispensing valve.

16. The tank ofclaim 15 wherein the air dispensing valve is a pushbutton or a pivotable lever that engages the pushbutton.

17. An air reservoir tank having a flashlight thereon.

18. The tank ofclaim 17 wherein the flashlight provides a carry handle for the tank.

19. The tank ofclaim 17 including a photovoltaic cell to supply electrical power to charge the flashlight.

20. An air reservoir tank having an air dispensing hose disposed on a reel that retracts the hose when it is not in use.

21. An air reservoir tank having an air pressure gauge to display air discharge pressure in the hose.

22. An air reservoir tank having a connector by which the tank can be held in position.

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