Patent ID: 12209499

DETAILED DESCRIPTION

The present disclosure relates to a compressed air driven inverter generator and the components thereof. An embodiment of the generator comprises an air motor, an inverter unit, a hub assembly connecting the air motor to a generator unit or permanent magnet alternator, and a housing.

Underground mines have massive networks of piping systems used to distribute compressed air throughout the whole mine. These networks of piping systems are very large and, in some cases, can total hundreds of kilometers in length. This results in compressed air storage on a massive level. The network of compressed air lines is always charged up to system pressure and maintained by large electric compressors located on surface. These lines have been in place long before electricity was routed to many locations in the mine(s). Before the introduction of electric powered equipment in underground mines, all the equipment was driven by compressed air or diesel. It served two purposes. 1: it served as an energy source for powering mining equipment and second the exhaust air from the equipment provided cool dry breathable air for the worker operating the equipment underground or in a confined space. Since electrically driven equipment is generally more efficient then air driven equipment, electric equipment has replaced most air driven equipment as prime movers. The electric driven equipment still uses the compressed air for other purposes. The compressed air infrastructure remains in use and is still one of the first of two services to be installed in new locations underground. The second is water and electricity usually comes last and only where need be due to the fact that it is much more costly to install. Almost all areas, new and old, in underground mines have compressed air and water available but less than 50% of these same areas have electricity. For the most part the compressors on surface very rarely shut down but in the event of a total power outage where even the compressors are off, the sheer scale of the compressed air infrastructure piping system stores enough compressed air energy to operate a Compressed Air Inverter Generator (as disclosed herein) for days or even weeks depending on how many units would be running. The disclosed Compressed Air Driven Inverter Generator would be an excellent choice for emergency situations.

The Compressed Air Driven Inverter Generator disclosed herein is primarily targeted at an underground mining environment or operating in confined spaces. However, it can be used in any situation requiring backup power or where no other source of power is available. The environmentally friendly prototype unit currently exhaust's 100% clean breathable air as a by-product while producing up 1800 watts continuously and 2200 watts momentarily of 120-volt clean AC electrical power. Air motors can also be completely stalled while under full air pressure for long periods of time without harm to the motor. Another advantage is that air motors do not produce any heat while operating. These advantages make the disclosed generator a safety-oriented apparatus.

A prototype generator according to the present disclosure used either GAST MVP05 or a GAST MVP06 motor made by GAST. Other motors can be used, such as the Ingersoll Rand 4800 series air motors, in particular the 4800D. These motors are high RPM, do not require oil, low maintenance, and extremely lightweight for the horsepower they produce.

Preferably, the generator comprises an air motor that does not require oil. The prototype unit is approximately 19.5″ tall×12″ wide×13″ deep and weighs approximately 51 lbs and can be easily carried by most workers. Other embodiments are possible. For example, output ranges from 1800 watts continuous to 2800 watts continuous are feasible.

The generators disclosed herein can be paralleled together to double the power output which has major advantages over a single larger unit. For example: a worker can carry one unit at a time to a location and then return to retrieve a second unit without the help of another worker. One unit at a time is easier to move twice than a larger heavier single unit. Another advantage of paralleled units is that it provides some redundancy: if two units are be operating to supply emergency power for critical equipment or in an emergency situation and one unit were to fail, you would still have one unit operating. Larger output units that are physically no larger than the smaller unit but slightly heavier (5 lbs) are also possible. The different units can be tailored for different applications underground. For example: a portable unit may be made of lightweight aluminum material with an easy to carry physical shape, have ergonomic friendly carry handles and only the necessary options to save weight, while another unit may be purchased primarily for emergency back-up power near a refuge station supplying power for a microwave, refrigerator, telephone, computer and mine radio system power supply unit or located in a switch-room operating remotely over the mine VHF radio system while supplying power for PLC units that monitor all kinds of critical levels.

Efficient inverter technology allows for variable speed operation to accommodate load, which reduces air consumption and noise levels at low power output level and reduces wear on the motor. For example, the unit can be programmed to only run at a proportional speed dictated by power demand.

The disclosed generators comprise a hub assembly that connects the output shaft of an air motor to a rotor of the generator and provides cooling for the generator and components. The design of the hub assembly serves six major functions. First, it serves the purpose of combining the air motor, stator, rotor into one small light-weight assembly. Second, it serves as a cooling system method” by way of the compressed cooling air passing through the cooling ports and a 360-degree channel in the hub and airholes in the diffuser plate and also introduces air flow into the chamber. Third, it serves as a single mounting point for the whole assembly (air motor, stator, cooling system, and rotor) to a housing of the generator. Fourth, the hub assembly allows perfect centering alignment of the stator and rotor with respect to the air motor shaft. Fifth, the hub assembly absorbs heat from the stator through surface contact. Sixth, the hub assembly serves as a place to secure a wiring harness exiting the stator to prevent the wiring from having contact to rotating parts.

In a preferred embodiment, the hub assembly is made of 6061 Aluminum Alloy. Other metals or suitable materials are possible, such as steel, ceramic or suitable plastics.

Referring toFIGS.1and2, one embodiment of the hub assembly100comprises a hub110, a hub spacer130, and a diffuser plate120, which are combined as one piece with bolts330,140and220. In use, air motor mounting bolts220attach the diffuser plate120to the hub110through mounting holes122in the diffuser plate and mounting holes116in the hub. Bolts140are sized to go through mounting holes132in the hub spacer130, mounting holes124in the diffuser plate and mounting holes118in the hub. Other methods of attaching the components are possible and in some embodiments the hub and hub spacer are machined as one piece.

Referring toFIGS.3A and3B, the hub100comprises a plate with a cylindrical protrusion113centered on a bottom face111and a bore hole114through the center of the plate and protrusion. In a preferred embodiment, the plate is circular. However, other shapes are possible, such as circular with flattened milled portions for mounting, oval, or even square or rectangular. The protrusion113is sized to fit into an inner bore hole of a stator320of a stator/rotor assembly300. The bore hole of the hub110is sized to fit around without contacting an output shaft210of an air motor200of the generator. The plate also has a closed loop trench115on the bottom face111, a plurality of cooling ports119through the hub evenly spaced in the trench115and a plurality of mounting holes116and118though the plate, and a socket117on a top face112opposite the bottom face111, the socket117being concentric with bore hole114and sized to fit around the exterior of the air motor200. In a preferred embodiment, the trench is circular.

The diffuser plate120is configured to attach to the bottom face111of the hub110with a plurality of air holes126extending through the diffuser plate120, the air holes126being in a circular pattern and centered on the trench115. In a preferred embodiment, the diffuser plate is circular. Other shapes are possible.

The hub spacer130contacts with a side of the diffuser plate120opposite the hub110. In a preferred embodiment, the hub spacer is ring-shaped. Other shapes are possible.

The hub110for the prototype model was machined from6061aluminum to save weight and to absorb heat from the stator320. The hub is a one piece unit and connects the stator320, rotor, air motor, cooling system into one assembly. The output shaft210of the air motor200sits inside a bore hole114of the hub110. In use, the output shaft210of the air motor200extends through the hub assembly100to the rotor/stator assembly300where it is bolted in place with a rotor mounting bolt330.

In some embodiments, the stator's inner bore hole sits on a machined shoulder323of the protrusion113to ensure that it is on center with respect to the output shaft210of the air motor200. In one embodiment, the stator320is bolted in place using 2 M5 bolts140that pass through the hub spacer130and diffuser plate120and thread into the hub110. More bolts or other methods of attachment are possible. The output shaft210of the air motor200comes through the borehole114of the hub110, diffuser plate120, hub spacer130and the center of the stator320. For one prototype, the output shaft of the air motor was modified with a 6-degree taper. The rotor310fits on to the output shaft210of the air motor200and is secured to the output shaft of the air motor with a bolt330(eg ¼″) into the center of the shaft210. The result is a centered rotor310that is fastened securely to the air motor's output shaft210and is centered over top of the mating stator320. In some embodiments, the hub110also has three mounting holes on the back side to secure this the hub assembly to a base plate of the generator housing.

In some embodiments, three cooling ports119are incorporated into the hub110. In some embodiments the cooling ports extend through the circular plate of the hub in the trench115. The cooling ports115in conjunction with the diffuser plate120aide in cooling the stator and rotor assembly300and other generator components.

The hub spacer130connects the hub110to the stator320. The hub spacer130serves four different functions. Function#1: The hub spacer is a mirror image of the stator's mounting face and acts as an interface between the hub and the stator for mounting purposes. Function#2: the hub spacer creates a gap between the stator windings and the diffuser plate120which creates room for the cooling air to expand and cover a wider surface area of the stator windings. Function#3: The gap created between the diffuser plate and the hub face also creates space for the wiring harness to extend out from the stator320windings. In a preferred embodiment, the hub spacer130is waterjet cut from 6061 0.375″ Aluminum plate or 375″ thick, 500 series Aluminum.

The diffuser plate120is for the purpose of redirecting pressurized air. When combined with the hub110it creates a 360-degree enclosed channel all the way around the bottom face111of the hub110. In a preferred embodiment, the diffuser plate120is machined from 6061 Aluminum. Other materials or means of manufacturing are possible. The diffuser plate111of one prototype has 12×0.100″ holes drilled through and centered over top of the trench115of the hub110. More or less holes are possible and other diameters of holes and combinations are possible. The cooling ports119allow pressurized air to enter the trench115, and then the air exits through the diffuser air holes126in a circular pattern. This circular pattern is located directly below the stator320windings and is used to remove heat from the stator windings and the rotor310.

In some embodiments of the disclosed generator uses a cooling system that utilizes a branch-off air circuit taken from the air motor's200inlet. The compressed air flows through a flow regulator to achieve a sufficient amount of flow for cooling purposes. In some embodiments, the branch off circuit is ¼″. The flow regulated air pressure will split into three separate lines (can be ¼″) and connect to three fittings attached to the top face112of the hub110at cooling ports119spaced at120degrees apart (around the air motor). More or less lines are possible. The pressurized air travels through three separate cooling ports119extending through the length circular plate of the hub110. As the cool, pressurized air travels through the cooling ports119, the air removes heat from the hub110that has been absorbed from the stator320. At the bottom face111of the hub110, there is a trench115in the form of a deep groove or channel in the face of the hub. In some embodiments the trench115is ¼″. The trench is in a circular pattern (360 degrees) cooling ports119exit into the trench115, thus creating a channel for the cooling air to be redirected by ninety degrees in two directions (or 180 degrees). The diffuser plate120is a plate that is a mirror image of the bottom face111of the hub110. In a preferred embodiment, the diffuser plate120has 12×0.100″ evenly spaced (30 degrees apart) diffusing air holes126drilled into it on the same radius as the 360-degree trench115in the hub110. The diffuser plate120when fastened to the hub110creates an enclosed channel 360 degrees around the entire hub110. The enclosed channel becomes pressurized by the cooling air and exits through the diffuser air holes126in an evenly spaced 360-degree pattern located directly below the stator320windings. The result is an evenly spaced spray pattern for the pressurized cooling air. The pressurized cooling air passes through the stator320in an even manner effectively cooling the stator windings.

The hub assembly100eliminates the need for separate a bearing housing, bearings, shaft couplings, separate mounting plate, and misalignment issues with the stator and rotor300with respect to the air motor output shaft210.

In one embodiment, the generator can be mounted to a wall or other such structure using a wall mount bracket. The wall mount bracket in some embodiments is a water jet cut mounting plate made from 500 series Aluminum. In some embodiments the wall mount bracket is made of 0.375″ thick, 500 series Aluminum alloy.

Referring toFIGS.4to10, in some embodiments, the generator400comprises a housing made up of a PMA (Permanent Magnet Alternator) cover452, a base plate430, a top plate460, a face plate470and a jacket450. The housing is designed to create an enclosed air chamber420in combination with the hub assembly100to provide cooling for the generator400and its components an to create a positive pressure atmosphere to keep dirt out of the chamber and away from the generator's moving parts.

The jacket450is u-shaped with three vertical walls and is shown in detail inFIGS.8A to8C. The PMA cover452attaches across a base plate430. The base plate430is u-shaped and with the open end of the U attaching to a back wall453of the jacket450. A bottom surface431of the base plate430attaches to the PMA cover452and a top surface432attaches to the back wall453of the jacket450. The top and bottom surfaces431and432of the base plate430cover the width of the jacket450. The air motor200extends through an opening433in the top surface431of the base plate430with the output shaft end attached to the hub assembly100being between the top surface431and the bottom surface432. The top plate460extends across a top end of the jacket450above the air motor200. An embodiment of the top plate460is shown inFIG.9A and9B. The face plate470extends from the top plate460to the base plate430across the open end of the U of the jacket450closing off the space in which the top portion of the air motor200is located.

An embodiment of the base plate430is shown in more detail inFIGS.10A and10B. The base plate430serves many purposes. The base plate430when combined with the jacket450and the PMA Cover452forms an enclosure for the stator320, rotor310, primary inverter unit440, voltage regulator (not shown), and wiring harness (not shown). The enclosure protects the equipment inside from the outside environment, and keeps the rotating equipment concealed within. In some embodiments, the enclosure has been designed so that positive air pressure is induced from the hub assembly located inside the enclosure and flows out through a vent located above the primary inverter unit. The result is a steady flow of cool air entering, removing heat, and exiting the enclosure while also keeping any dirt or debris out of the enclosure. The top surface431of the base plate430also provides a place to mount the primary inverter unit, voltage regulator, and hub assembly and in the preferred embodiment, with 3 bolts. The base plate also provides structural strength to the jacket450. In one embodiment, the base plate is made of 500 series aluminum. Aluminum also provides excellent heat dissipation. In the preferred embodiment, the base plate is made of 0.187″ thick, 500 series aluminum alloy. Other materials and sizes are possible.

The top plate460, when assembled with the jacket, face plate and the base plate, forms an enclosed area to house the air motor, air control circuits, Main Control Board, and many other items involved in the operation of the generator. The top plate also serves as mounting for a main air shut-off valve and the face plate and provides structural strength to the jacket and face plate. A preferred embodiment of the top plate is made of 0.187″ thick, 500 series Aluminum alloy. Other materials and sizes are possible.

The face plate470, shown inFIGS.6and7, is primarily designed to provide a place to mount outside controls and user interface. The face plate also provides structural strength to the top plate, base plate, and the jacket. A preferred embodiment of the face plate is made from 0.187″ thick 500 series Aluminum alloy. Non-limiting examples of the outside controls include: 20-amp GFCI receptacle; 20-amp Circuit breaker; Red indicator; Green indicator; 4×20 LCD display; Key switch; Bonding terminal (for earth grounding); Emergency stop button; parallel terminals; and Green pneumatic push button (start).

The jacket450primarily serves as a shell and when combined with all the other pieces of the housing will form the entire enclosure for the “The Compressed Air Inverter Generator”. A preferred embodiment of the jacket is made from 0.187″ thick 500 series Aluminum alloy. Other materials and sizes are possible.

The PMA cover452is designed to act as an access port to gain access to the stator, rotor, hub assembly, primary inverter unit, voltage regulator, and other devices inside the enclosure. A preferred embodiment of the PMA cover has a rubber gasket to seal the enclosure from dirt and debris. The PMA cover connects to the bottom surface432of the base plate430. In a preferred embodiment, the PMA cover bolts on to the bottom surface432of the base plate430. A preferred embodiment of the PMA cover is made from 0.187″ thick 500 series Aluminum alloy. Other materials and sizes are possible.

The stator320, rotor310, inverter unit440, and voltage regulator (not shown) are enclosed in an enclosure formed by the assembly of the base plate430, jacket450, and a PMA (Permanent Magnet Alternator) Cover. The inverter unit440is mounted inside the chamber with heatsinks facing the top of the base plate. In one embodiment, the base plate has water jet cut vents located directly above the inverter unit's heatsink. The pressurized cooling air flows across the heat sink of the inverter unit and exits through the cooling air exhaust vent holes in the top of the base plate and out to atmosphere. The result is a positive pressure enclosed cooling chamber formed by the assembly of the base plate, jacket and the PMA Cover. The cooling air exhaust vent that is located in the top of the base plate may or may not have a fine mesh stainless steel screen or paper filter to eliminate debris from entering the enclosed chamber when the unit is off. This cooling method does not require a fan. One major advantage is that when the electrical load increases, the air motor inlet pressure will increase simultaneously, effectively increasing cooling air flow to the unit. The design is simple and effective, and the cost is minimal.

The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The exemplary embodiment was chosen and described in order to best explain the principles of the present invention and its practical application, to thereby enable others skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated.