CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application Serial No. 62/022,352, filed July 9, 2014, titled "Vacuum Generator Flow Diverter," the entire contents of which are hereby incorporated by reference.

FIELD OF THE DISCLOSURE

[0002] Embodiments 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

[0003] Vacuum 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. [0004] Existing 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 FIG. 1. Improvements to this configuration are desired

BRIEF SUMMARY

[0005] Embodiments 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. [0006] Without 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] FIG. 1 shows a side cross-sectional view of a vacuum generator system. [0008] FIG. 2 shows a side cross-sectional view of a vacuum generator system employing a diverter as described herein.

[0009] FIG. 3 shows a side perspective view of one embodiment of a diverter.

[0010] FIG. 4 shows a sectional view of a diverter in place in a vacuum generator housing.

DETAILED DESCRIPTION

[0011] Embodiments 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 10 comprises a housing 12 coupled to a motor assembly (not shown). In most instances, a regenerative impeller 14 is positioned within the housing 12 and is driven by a drive shaft of the motor assembly to generate vacuum. An example of this configuration is shown by FIG. 2. In this example, the housing 12 comprises an inside housing portion 16 and an outside housing portion 18. The housings portions 16 and 18 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. [0012] Maintaining vortex separation between the housing portions 16, 18 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 12, resulting in poor circulation.

[0013] As shown in FIG. 2, a diverter 20 may be provided. With the diverter 20 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 20 is illustrated by FIGS. 3 and 4. As shown, the diverter 20 may have a securement flange 22 with one or more openings 24 for receiving a fastener. The diverter 20 may also have first and second upper walls 26 and 28. The upper walls and 26, 28 create a ceiling for the diverter 20 that abuts the housing 12 in use. (The term "upper" is used only to refer to the position of the walls when the diverter 20 is positioned in place in the housing 12.) The diverter 20 may also have an air flow flange 30. The air flow flange 30 extends downwardly and centrally from the upper walls 26, 28. The airflow flange 30 provides an outward arrow- like projection that helps to divide the interior of the housing and direct air flow. The airfiow flange 30 is generally positioned above the impeller tip 32 in use, as illustrated by FIG 2.

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

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

[0016] FIG. 3 shows a diverter 20 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 20 circumference will depend upon the housing shape.

[0017] As shown in FIGS. 2 and 4, the diverter 20 may be sandwiched between housing portions 16, 18. It creates two distinct flow vortices VI and V2, 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 10. It does, however, add strength to the housing 12.

[0018] The diverter 20 may be installed with any appropriate method. For example, the diverter 20 may be sandwiched in place between the housing portions 16, 18. In this example, the securement flange 22 may be held via friction fit. In another example, the diverter 20 may be fastened via one of the flange openings 24, with a fastener being extended through the fiange opening and secured to the housing 12. In another example, the diverter 20 may be welded to one or more of the housing portions. In another example, the diverter 22 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 20 is positioned so that the airflow flange 30 separates the airflow generated by the impeller 14.

[0019] The material of the diverter 20 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. [0020] One 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.

[0021] Because the diverter 20 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.

[0022] The diverter 20 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. [0023] The 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.) [0024] In prior designs, without a diverter 20 in place, the air is forced to make the turn shown on FIG. 1 by itself. By providing a diverter 20, the air may be properly directed and circulation improved. The air is allowed to flow along curved surfaces 34, 36, as well as along the inner curved surfaces 38 of the housing 12. The diverter provides a dividing function, as well as an airflow guiding function.

[0025] Changes 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.