Vacuum generator flow diverter

CROSS REFERENCE TO RELATED APPLICATIONS

0001This application claims the benefit of U.S. Provisional Application Ser. No. 62/022,352, filed Jul. 9, 2014, titled “Vacuum Generator Flow Diverter,” the entire contents of which are hereby incorporated by reference.

FIELD OF THE DISCLOSURE

0002Embodiments of the present disclosure relate generally to systems and methods for improving vacuum generator function. Embodiments particularly relate to vacuum generators for aircraft or other transportation vehicles. Specific examples find particular use in connection with vacuum generators used to operate a waste system on board an aircraft or vehicle during ground or low altitude operations.

BACKGROUND

0003Vacuum systems are used to forcefully withdraw waste and rinse water from the toilet bowl of aircraft toilet systems for delivery to a main waste holding tank. In such systems, the tank is situated remotely and vented to the atmosphere outside the aircraft, and the toilet bowl is situated inside the pressurized passenger cabin and maintained at cabin pressure. At altitudes generally above 15,000 feet, the difference in pressure between the atmospheric pressure outside the aircraft and the cabin pressure inside the aircraft causes sufficient air flow/vacuum from the toilet bowl to the tank to transport the waste. At ground level and at altitudes generally below 15,000 feet, a vacuum generator is used to artificially create or supplement vacuum in the waste tank and pipes sufficient to transport the waste and rinse water.

0004Existing vacuum pump generators use a regenerative impeller with air recirculating between the blades. The impeller is positioned within an impeller housing. This creates two vortexes, one on either side of the impeller. In some instances, poor circulation exists where air flow contacts the impeller housing. The air makes ninety degree turns in separate directions. An example of this airflow is shown by <figref idref="DRAWINGS">FIG. 1</figref>. Improvements to this configuration are desired

BRIEF SUMMARY

0005Embodiments of the invention described herein a provide flow diverter for improving flow circulation of fluid pumps. Embodiments provide systems and methods for providing improved air flow for vacuum generator systems. The systems may include a housing with an impeller and a diverter having an airflow flange comprising an arrow-like projection configured to extend into an airflow space of the housing. The diverter may have curved surfaces that help guide airflow movement within the housing.

0006Without the diverter in place, air or other fluid flow may not be properly directed or may experience stagnation. The diverter described herein directs air/fluid flow to its intended path. It also separates the fluid circulation on each side of the impeller, reducing or eliminating flow mixing and improving pump efficiency. The diverter may also strengthen the impeller housing by adding material to its wall thickness, which can be beneficial for safety because the containment strength is increased.

BRIEF DESCRIPTION OF THE DRAWINGS

0007<figref idref="DRAWINGS">FIG. 1</figref> shows a side cross-sectional view of a vacuum generator system.

0008<figref idref="DRAWINGS">FIG. 2</figref> shows a side cross-sectional view of a vacuum generator system employing a diverter as described herein.

0009<figref idref="DRAWINGS">FIG. 3</figref> shows a side perspective view of one embodiment of a diverter.

0010<figref idref="DRAWINGS">FIG. 4</figref> shows a sectional view of a diverter in place in a vacuum generator housing.

DETAILED DESCRIPTION

0011Embodiments of the present invention provide a diverting gasket that can help control air circulation in a vacuum generator. An exemplary embodiment of a vacuum generator system <b>10</b> comprises a housing <b>12</b> coupled to a motor assembly (not shown). In most instances, a regenerative impeller <b>14</b> is positioned within the housing <b>12</b> and is driven by a drive shaft of the motor assembly to generate vacuum. An example of this configuration is shown by <figref idref="DRAWINGS">FIG. 2</figref>. In this example, the housing <b>12</b> comprises an inside housing portion <b>16</b> and an outside housing portion <b>18</b>. The housings portions <b>16</b> and <b>18</b> may be coupled to one another using fasteners. The housing portions may be made of an aluminum alloy to provide a lightweight construction. Other possible materials for the housing include titanium, stainless steel, carbon fiber, or any other appropriate material. It is preferred to use materials that are sufficiently lightweight to provide the advantages described, but that also provide the required structural integrity of the design.

0012Maintaining vortex separation between the housing portions <b>16</b>, <b>18</b> is useful, but there have been problems with previous attempts. For example, it is not desirable to machine a housing with an overhanging lip. Adding a flange to the impeller has also been found to be ineffective. Embodiments described herein thus address the issue of flow stagnation where the air (or other fluid) hits an orthogonal wall of the impeller housing <b>12</b>, resulting in poor circulation.

0013As shown in <figref idref="DRAWINGS">FIG. 2</figref>, a diverter <b>20</b> may be provided. With the diverter <b>20</b> in place, air flow (illustrated by arrows “A”) may be diverted to its intended direction, resulting in improved fluid circulation. One example of a diverter <b>20</b> is illustrated by <figref idref="DRAWINGS">FIGS. 3 and 4</figref>. As shown, the diverter <b>20</b> may have a securement flange <b>22</b> with one or more openings <b>24</b> for receiving a fastener. The diverter <b>20</b> may also have first and second upper walls <b>26</b> and <b>28</b>. The upper walls and <b>26</b>, <b>28</b> create a ceiling for the diverter <b>20</b> that abuts the housing <b>12</b> in use. (The term “upper” is used only to refer to the position of the walls when the diverter <b>20</b> is positioned in place in the housing <b>12</b>.) The diverter <b>20</b> may also have an air flow flange <b>30</b>. The air flow flange <b>30</b> extends downwardly and centrally from the upper walls <b>26</b>, <b>28</b>. The airflow flange <b>30</b> provides an outward arrow-like projection that helps to divide the interior of the housing and direct air flow. The airflow flange <b>30</b> is generally positioned above the impeller tip <b>32</b> in use, as illustrated by <figref idref="DRAWINGS">FIG. 2</figref>.

0014Extending between the first upper wall <b>26</b> and the airflow flange <b>30</b> is a first curved surface <b>34</b>. Extending between the second upper wall <b>28</b> and the airflow flange <b>30</b> is a second curved surface <b>36</b>. Curved surfaces <b>34</b>, <b>36</b> help guide airflow A, as is shown in <figref idref="DRAWINGS">FIG. 2</figref>. The curved surfaces <b>34</b>, <b>36</b> can follow the shape of and generally be a natural extension of the inner curved surfaces <b>38</b> of the housing <b>12</b>. One example of this is illustrated by <figref idref="DRAWINGS">FIG. 4</figref>, showing curved surfaces of the diverter and how they cooperate with the inner curved surfaces <b>38</b> of the housing <b>12</b>.

0015The shape of the diverter <b>20</b> may vary, depending upon the shape and size of the housing <b>12</b>. The general goal is for the space <b>40</b> between the arrow-like air flow flange <b>30</b> of the diverter <b>20</b> and the impeller tip <b>32</b> to be as small as possible without impeding impeller motion. In some embodiments, this space <b>40</b> may be about one inch or less. In other instances, the space may be about ½ inch or less. The height/width of the diverter <b>20</b> depends upon the housing and impeller dimensions. The diverter <b>20</b> can be sized for any application or installation. It may be scaled based on size of the intended housing <b>12</b>, impeller <b>14</b>, and flow cavity.

0016<figref idref="DRAWINGS">FIG. 3</figref> shows a diverter <b>20</b> that has a flow path extending around about ¾ of a full circle. It is possible to provide a diverter gasket that has a ½ flow path, ¼ flow path, a full flow path, or any other option. The external shape of the diverter <b>20</b> circumference will depend upon the housing shape.

0017As shown in <figref idref="DRAWINGS">FIGS. 2 and 4</figref>, the diverter <b>20</b> may be sandwiched between housing portions <b>16</b>, <b>18</b>. It creates two distinct flow vortices V<b>1</b> and V<b>2</b>, minimizing air from mixing. This has been found to potentially improve efficiency of the vacuum generator. It is also believed that the diverter does not add mass or inertia to the system <b>10</b>. It does, however, add strength to the housing <b>12</b>.

0018The diverter <b>20</b> may be installed with any appropriate method. For example, the diverter <b>20</b> may be sandwiched in place between the housing portions <b>16</b>, <b>18</b>. In this example, the securement flange <b>22</b> may be held via friction fit. In another example, the diverter <b>20</b> may be fastened via one of the flange openings <b>24</b>, with a fastener being extended through the flange opening and secured to the housing <b>12</b>. In another example, the diverter <b>20</b> may be welded to one or more of the housing portions. In another example, the diverter <b>22</b> may be bonded or otherwise adhered to the housing, press fit or slide fit, or secured by any other appropriate installation method. The general goal is that the diverter <b>20</b> is positioned so that the airflow flange <b>30</b> separates the airflow generated by the impeller <b>14</b>.

0019The material of the diverter <b>20</b> may be a material that has sufficient strength to guide diverted air. It may be manufactured of a metallic material, such as aluminum. It may be manufactured of a plastic material, such as PTFE, polypropylene, or any other plastic or polymer. It may be manufactured of gorilla glass (which is alkali-aluminosilicate sheet toughened glass), a ceramic, or any other appropriate material. One specific embodiment may be manufactured of 6061-T6 Aluminum, machined from bar stock.

0020One of the goals is for the fabrication and/or tooling method to be accurate so that the dimensions of the flow diverter (which control its fit in the housing and its function) are accurate and can direct flow as desired. Any of the possible and latest fabrication techniques (offering choice of material as well as a blend of polymer and metal) could provide the desired form and provide an effective design shape and fit without hindering it mechanical strength and/or chemical resistance strength for aerospace application.

0021Because the diverter <b>20</b> may come into contact with air and water, it may be manufactured of a non-corrosive material and/or it may have a coating that can help prevent corrosion. Possible materials include but are not limited to aluminum, anodized metal, PTFE, ceramic, gorilla glass, or any other appropriate material. If the material is anodized (which creates pores in the outer surface), it may also be coated as described below in order to prevent odor or build-up of undesired particles.

0022The diverter <b>20</b> may be coated with one or more anti-microbial agents, polymers, coatings, or materials. The one or more anti-microbial agents may be provided in order to prevent growth of bacteria, viruses, algae, parasites, or any other undesirable growth that may otherwise occur. The term “antimicrobial” is used herein to encompass, but not be limited to, all potential compounds that kill or inhibit the growth of bacteria, fungus, mold, mildew, parasites, microorganisms, viruses, and any other unwanted species that may grow in a space. The term is intended to encompass, but not be limited to, any types of antimicrobials, antiseptics, disinfectants, biocides, sterilizers, deodorizers, decontaminants, purifiers, or any other substances that inhibit, treat, and/or prevent or inhibit unwanted growth of any of the above-described or other species. Various types of anti-microbial chemistry are known, but non-limiting examples of potential materials that may be used may be manufactured by any number of chemical companies (non-limiting examples of which include Dow Chemical, BASF, DuPont, Microban, Total Science Antiseptic Solutions, and/or Eastman Chemical). Such materials or agents or coatings can prevent a film from being formed on the diverter air intake.

0023The flow diverter devices described herein may be made by machining, molding, sintering, modeling, or any other appropriate tooling method, using any applicable material. In one embodiment, if plastics (such as thermoplastics, ABS, polycarbonate, polyphenylsulfone) or elastomers are to be used, the diverter may be manufactured by Fused Deposition Modeling (FDM). In other embodiments, Selective Laser Sintering (SLS) may be used. (For instance, for powdered polymer and/or metal (steel powder) composite materials, thermoplastics such as nylon, polyamide, or polystyrene; elastomers; composites.) In other embodiments, Direct Metal Laser Sintering (DMLS) may be used. (For instance, for metal powder free of binder; for ferrous metals such as steel alloys, stainless steel, tool steel; for non-ferrous metals such as aluminum, bronze, cobalt-chrome, titanium; ceramics.)

0024In prior designs, without a diverter <b>20</b> in place, the air is forced to make the turn shown on <figref idref="DRAWINGS">FIG. 1</figref> by itself. By providing a diverter <b>20</b>, the air may be properly directed and circulation improved. The air is allowed to flow along curved surfaces <b>34</b>, <b>36</b>, as well as along the inner curved surfaces <b>38</b> of the housing <b>12</b>. The diverter provides a dividing function, as well as an airflow guiding function.

0025Changes and modifications, additions and deletions may be made to the structures and methods recited above and shown in the drawings without departing from the scope or spirit of the disclosure or the following claims.