Patent ID: 12215924

DETAILED DESCRIPTION

The following description and associated figures teach the best mode of the invention. For the purpose of teaching inventive principles, some conventional aspects of the best mode may be simplified or omitted. The following claims specify the scope of the invention. Note that some aspects of the best mode may not fall within the scope of the invention as specified by the claims. Thus, those skilled in the art will appreciate variations from the best mode that fall within the scope of the invention. Those skilled in the art will appreciate that the features described below can be combined in various ways to form multiple variations of the invention. As a result, the invention is not limited to the specific examples described below, but only by the claims and their equivalents.

FIG.1illustrates an oxygen extraction system100according to one embodiment. System100draws gaseous atmospheric air into an air intake102and removes humidity from the air in a dehumidifier104. Removal of the humidity from the input air removes water vapor from the air that could easily freeze and block the process or reduce its efficiency. After drying the air in dehumidifier104, system100compresses the air in a compressor106. A motor108is configured to run compressor106to compress the gaseous air into a liquid state.

After being compressed into a liquid, the liquid air passes through a separator110designed to extract oxygen from the other liquid gases of the liquid air. As described below, separator110functions magnetically to draw the liquid oxygen from the liquid air passing through a shaped tube. The extracted liquid oxygen in this embodiment is stored in an oxygen storage tank112fluidly coupled to separator110to store the oxygen in its liquid state. The process of extracting at least a portion of the oxygen from the liquid air flowing through the separator110produces a liquid mixture of the liquid air having at least a portion of oxygen removed therefrom. This liquid mixture flows from the separator110to an expander114configured to expand the liquid gases into a gaseous state for ejection back into the environment through a gas outtake116. Air intake102and gas outtake116are preferably positioned far away from each other to avoid the less-oxygenated exit air from being drawn back into oxygen extraction system100.

As illustrated, heat generated in the compression stage via compressor106and in the separation stage via separator110is provided to expander114in the expansion stage. In turn, mechanical energy generated in the expansion stage is provided back to the compression stage. In this way, the shared heat and energy between the compression and expansion stages reduces the amount of external work needed to be entered into the system100and reduces the amount of external cooling needed to compress the intake gas. Motor108is provided to add mechanical energy to maintain the process continuously to overcome any energy losses in the heat and mechanical energy transfer120between the stages. If needed, it is contemplated that a cooling subsystem may be incorporated to compensate for heat generated by the system100.

The separation of oxygen from the liquid air via separator110in the separation stage may not completely remove all of the oxygen from the liquid air. Instead, a liquid mixture produced by separator110as its output may only have a portion of the oxygen removed. Accordingly, it is contemplated that system100may include a feedback system118coupled to the separator110to pass the liquid mixture of gases back through separator110one or more additional times to further extract remaining oxygen from the liquid air. Each subsequent pass of the liquid mixture produced by separator110is intended to remove more oxygen therefrom, thus increasing the efficiency of the system100in removing the oxygen.

FIG.2illustrates an oxygen extraction system200with an additional expansion stage. System components in common with system100are described above. In the embodiment shown, another expander202fluidly coupled to separator110is included and coupled to the oxygen output of separator110to take advantage of expanding the liquid oxygen back to its gas state to recoup more of the energy of compression and extract extra heat from the compression process. Oxygen storage tank112is fluidly coupled to expander202to store the oxygen in its gaseous state. In expander202, the capture of energy produced via the compression and expansion stages is leveraged. Both expanders114,202transfer mechanical energy and heat120back to and from the compressor106, respectively.

In a typical concentration of air, the following gases and percentages are found: nitrogen (78.09%), oxygen (20.95%), argon (0.93%), carbon dioxide (0.03%), and water vapor (varies). The magnetic property of oxygen is paramagnetic while the magnetic properties of nitrogen, argon, carbon dioxide, and water vapor is diamagnetic. Accordingly, oxygen molecules are effectively attracted to magnetic fields while the molecules of these other gases are effectively repelled by magnetic fields. The extraction of liquid oxygen from the liquid air in embodiments herein is done by using the paramagnetic property of oxygen.

By applying a magnetic field gradient to the liquid oxygen, the oxygen separates from the other diamagnetic gases. Depending on the strength gradient of the magnetic field, the oxygen is separated with more or less speed. The larger the magnetic field gradient, the greater the efficiency at separating the oxygen. Magnetic field gradients much greater than 1 Tesla/meter are preferred. Permanent magnets of 1 Tesla (IT) are commonly available today using available neodymium magnets that can reach an extreme field of 1.4 T, for example. However, merely placing a IT magnet next to liquid air will not create a large gradient on its own. To achieve the large gradient magnetic gradient, special arrangements of the magnets is used.

By using or creating a C-shaped magnet or by placing the north pole of a magnet very close to the south pole of itself or another magnet and ensuring that the magnetic tips are small enough to force the magnetic field to squeeze, large magnetic fields become available in very small spaces. This magnetic field gradient may be used in the oxygen extraction systems100,200described above.

FIG.3illustrates a portion of the separator110of systems100,200. The air that has been liquefied via the compressor106is provided to and fed through the interior of an X-shaped tube300positioned between four magnet ends302-308. In one embodiment, magnet ends302,304are the respective north and south ends of a single, C-shaped magnet310(as shown) while magnet ends306,308are the respective north and south ends of a different single, C-shaped magnet312. As shown, magnet ends302,304are respectively positioned adjacently to adjacent walls314,316of tube300, and magnet ends302,304are respectively positioned adjacently to adjacent walls318,320of tube300. Alternatively, magnet ends302-308may be distinct, individual magnets (e.g., magnets600,602inFIG.6) with their north and south poles appropriately positioned as described herein.

FIG.4illustrates an embodiment of separator tube300shown in a cross-sectional view. As shown in this embodiment and as discussed above, tube300has an “X” shape. The X shape is formed by a portion of each wall314-320having a respective pair of concave portions400,402and a respective pair of convex portions404,406. The arms of the X shape are formed by respective pairs of a concave portion402and a convex portion406of one wall (e.g., wall318) together with respective pairs of a concave portion400and a convex portion404of an adjacent wall (e.g., wall316).

Referring again toFIG.3, the magnetic flux lines322that occur when placing the magnet ends302-308adjacently to one other are illustrated. The magnets are positioned within the gaps of the X-shape tube300such that the magnetic field is strongest at the limits of the arms of the X (i.e., adjacent to the apex of adjacent convex portions404,406). By pushing the liquid air through the interior324of the X-shape tube300, the oxygen will naturally be attracted to the highest magnetic field away from the center of the tube300while the non-oxygen gases will not be attracted to the limits. Instead, they will be somewhat pushed out due to the higher concentration of oxygen at the extremities. Since the center of the X-shape tube300has the lowest gradient of magnetic field, it helps keep the diamagnetic gases in the center of the tube300. The preferred gradient of the magnetic field needed to separate oxygen is 10 Tesla/meter, which can be achieved for short range distances with a IT magnet as shown. The X-shape is one of many permutations that are possible to create this 10 T/m gradient. The proposed four magnets with opposite poles towards each other can be extended to 2 N count of magnetic poles, and the X-shape will be replaced by a tube with 2 N arms extended between the magnets. It is also possible to arrange the magnets such that all the magnets have the same poles centered, and this arrangement can be used for even or odd numbers instead of balancing the magnetic poles in the 2 N magnets. However, having all the magnets centered would create a constant force pushing the magnets away from each other adding strain to the fixture holding the magnets. Using C-shaped magnets with the opposite poles centralized reduces complexity.

FIG.5illustrates an embodiment of tube300of separator110shown in an isometric view. As the concentration of oxygen mounts along the flow path of the X-shape tube300, apertures or side exit ports500in a wall502of the X-shape tube300extract the pure oxygen out of the tube to a separate channel. Ports500may be connected to extraction tubes (shown inFIG.6) to facilitate extraction of the oxygen. The extracted oxygen can be used in liquid form and stored in oxygen storage tank112as shown inFIG.1or expanded to a gas and stored in oxygen storage tank112as shown inFIG.2, which allows the system to recoup the compression energy contained in the liquid oxygen as described above.

FIG.6illustrates an isometric view of a portion of the separator110ofFIG.3according to an embodiment. As shown, magnets600-608extend along the length of tube300. Magnets600-608correspond to the position of magnet310. For simplicity in the drawing, additional magnets that would be paired with magnets600-608and corresponding to the position of magnet312are not shown. However, it is to be understood that such magnets would be present in a physical system. Between magnets600-608, the side exit ports400of tube300allow for the oxygen to be extracted. A plurality of extraction tubes610fluidly coupled to side exit ports400allow for the extracted oxygen to be provided to oxygen storage tank112in the case of system100or to be provided to expander202in the case of system200.

In another embodiment,FIG.7shows another shape of an extraction tube700configured to match the process as oxygen is removed from the liquid air passing therethrough. As shown, a first end702of tube700is X-shaped as described above. Along the length of tube700toward a second end704, the shape transforms from an X-shape into a circular shape. In one embodiment, the area of the cross-section of second end704is less than the area of the cross-section of first end702. For example, the area of the cross-section of second end704may be 0.8 times the area of the cross-section of first end702to take into account the removal of the volume of the oxygen from the liquid air as it travels along tube700. Also, side exit ports706along tube700may diminish as the need to remove oxygen from the liquid air lessens as oxygen is removed along tube travel.

The included descriptions and figures depict specific implementations to teach those skilled in the art how to make and use the best mode. For the purpose of teaching inventive principles, some conventional aspects have been simplified or omitted. Those skilled in the art will appreciate variations from these implementations that fall within the scope of the invention. Those skilled in the art will also appreciate that the features described above can be combined in various ways to form multiple implementations. As a result, the invention is not limited to the specific implementations described above, but only by the claims and their equivalents.