Two-stage flush and grey water flush systems and devices

Embodiments of the present invention provide a grey water flush system for use with vacuum toilets. One embodiment of the system provides a two-stage flush that uses a transient tank in between the toilet bowl and the main aircraft waste tank, which reduces the noise level associated with the flush process because a lesser vacuum is demanded for the first stage of the flush. Embodiments of the system further capture grey water from a sink basin in a reservoir and use that water in the toilet flush process. There is further provided a lavatory odor removal system option that is activated during the second stage of the flush.

FIELD OF THE INVENTION

Embodiments of the present invention generally relate to flushing systems for use with vacuum toilets. Certain embodiments find particular use on-board passenger transport vehicles as they seek to reduce noise levels by providing a flushing cycle that demands lesser vacuum levels for at least a portion of the flush cycle. Certain embodiments also help reduce aircraft weight and water by reusing grey water in the flush cycle.

BACKGROUND

Many types of passenger transport vehicles (such as aircraft, ships, buses, trains, and any other passenger transport vehicles) use vacuum toilets in order to flush septic waste, which is then delivered to a septic holding tank on board the vehicle. Such septic holding tanks are typically fluidly connected to the vacuum toilet system via a series of conduits, valves, and vacuum pumps in order to flush and route septic waste to the holding tanks. The vacuum created for the flushing action may either be via one or more vacuum pumps, or, in the case of an aircraft in flight, via a pressure differential. For example, aircrafts typically have a vacuum disposal system that applies a vacuum to pull waste media and flush water/spent water from toilets and/or sinks into an on-board waste water storage tank. The suction is generated either by the pressure differential between the pressurized cabin and the reduced pressure outside of an aircraft at high flight altitudes or by a vacuum generator at ground level or at low flight altitudes.

Although efficient, vacuum toilets create a loud noise level during the flush cycle, due to the amount of vacuum that needs to be applied in order to cause the septic waste to travel from the toilet basin to the holding tank. A loud flushing sound is created when the flush valve opens; the differential pressure is what forcefully draws the waste down the drain, and the pressure differential must be large enough to cause the waste to flow the entire distance from the toilet basin to the septic holding tank, which can be located quite far from the lavatory.

In addition to vacuum toilets, passenger lavatories also contain sinks for hand washing. For example, most commercial aircraft are equipped with galley and lavatory sinks. These sinks are typically intended for the disposal of fluid waste, soiled water from hand washing, and so forth. The spent water from sinks is referred to as “grey water,” as opposed to “black water” which has a urine or fecal component. (In addition to hand-washing water overflow from the lavatory, grey water can also include water from galley sinks Fluids from the galley can contain items such as leftover portions of beverages and water from melting ice, or any other form of “used” or spent water that drains from the water system. Grey water can also drain from wash basins during hand washing, or any other instance in which water is soiled or loaded with waste, such as e.g., soaps, detergents, soils from hand washing, and so forth). These sinks are typically connected to small diameter drain lines (which can easily back up if clogged) and may either terminate at the aircraft drain mast for exhaustion to the atmosphere or may be delivered to a grey water holding tank. Although most large passenger transport vehicles are equipped with a grey water system for collecting, storing and ultimately disposing of grey water, providing a separate grey water holding tank is not always economical due to the additional weight that such systems add to the aircraft. (In the absence of special valves, such as those described by U.S. Pat. No. 7,533,426 titled “Grey Water Interface Valve Systems and Methods,” health standard guidelines for airlines require that septic water (“black water”) be vacuumed away separately from grey water because, if a back-up were to occur, sewage would be expelled from galley and lavatory sinks, as well as toilets, which could create a myriad of health problems.) Accordingly, the added expense of keeping grey and black water separate has generally been necessary.

The present inventors have sought to provide a way to re-use the grey water in connection with a toilet basin flush system. Although vacuum toilets use much less water than a typical gravity flow toilet, it is still desirable to find a way to re-use the spent/grey water rather than using fresh water for each flush cycle, due to cost and weight considerations of maintaining fresh water on-board. The present inventions have also sought to reduce the noise associated with vacuum flushing. They have further sought to provide new ways to vent plumbing conduits in order to help remove odors from the vacuum flushing system.

BRIEF SUMMARY

Embodiments of the invention described herein thus provide a grey water flush system for use with vacuum toilets. One embodiment of the system provides a two-stage flush that uses a transient tank in between the toilet bowl and the main aircraft waste tank, which reduces the noise level associated with the flush process because a lesser vacuum is demanded for the first stage of the flush. Embodiments of the system further capture grey water from a sink basin in a reservoir and use that water in a typical flush process or in the two-stage toilet flush process described. The two-stage flush and the use of grey water as flush water may be used on their own or in combination with one another. There is further provided a lavatory odor removal system option that is activated during the second stage of the flush.

DETAILED DESCRIPTION

Embodiments of the present invention provide a way to use grey water (e.g., spent water from a faucet or sink basin, typically in the lavatory) for flushing a vacuum-based toilet. Although the embodiments are described herein with respect to an aircraft vacuum toilet system, it should be understood that the features shown and described may be used in connection with any type of vacuum toilet system, such as those positioned on-board sea-going vessels, trains, buses, and even stationary buildings that use vacuum toilet systems.FIG. 1illustrates a grey water flush system10is used in connection with a lavatory on-board a passenger transport vehicle. Typical lavatories have a wash basin12and a vacuum toilet bowl/basin14. The toilet bowl14is generally connected to a main waste line16which leads to a waste storage/holding tank18. As discussed above, during a typical flush cycle, waste from the toilet bowl14is suctioned through the main waste line16via a strong suction that causes the waste to travel from the bowl14to the holding tank18via a single application of vacuum.

The present system adds a two-stage flush. The two-stage flush is accomplished by providing a transient waste tank20plumbed in-line between the toilet bowl14and the main aircraft waste holding tank18. In a specific embodiment, the transient tank20is attached to or otherwise connected close by the toilet bowl14. As shown inFIG. 2, a first valve22is positioned between the vacuum toilet bowl14and the transient waste tank20. When a flush sequence is triggered, waste in the bowl14is transferred from the bowl14to the transient tank20through valve22. This is a relatively short distance, as compared to transferring the waste all the way to the main waste holding tank18. The transient tank20is thus necessarily charged with only small amount of vacuum; just enough to pull the waste the short distance from the toilet bowl14to the transient tank20. (One exemplary design showing a specific configuration between the bowl14and the tank is illustrated inFIG. 7.) This first stage of the two-stage flush process reduces the noise level associated with a full flushing cycle (from the vacuum toilet bowl14into the main waste holding tank18) by demanding a lesser vacuum for the transfer of waste into the transient waste tank20.

Once the waste has been transferred to the transient tank20, the second stage of the flush can begin. This second stage is the stage in which the waste in the transient tank is moved to the main waste tank. In this stage, the valve22closes and one or more additional valves are allowed to open. In a specific embodiment, the second stage of two-stage flush has two features—one feature is a waste transfer step and a second feature is an odor removal step. It is expected that for optimal functioning, both of these features function simultaneously together, and the valves controlling each feature open at the same time. This provides sufficient air flow to help move the waste out of the transient tank20and through lines16to the main tank18. However, it should be understood that these features and valves may function as two separate steps, such that one step (waste transfer) occurs followed by a separate step (odor removal). For the sake of convenience, the first feature of waste transfer step is described first.

During the waste removal step, the valve22closes and the valve24opens. Valve24is positioned between the transient waste tank20and the main waste tank18. Valve22may be connected to a pump and/or an actuator that controls a motor with preprogrammed microprocessor logic, such that immediately or shortly after valve22closes, a second valve24opens. (As discussed, the odor removal valve32may also open at this same time, even though its steps are described separately.)

The second valve24is positioned between the transient waste tank20and the main waste line16(which leads to main waste tank18). During this second stage of the two-stage flush, a moderate to large vacuum is applied to transfer the waste from transient waste tank20to the main aircraft waste tank18. This split waste transfer operation is achieved by a multi-valve sequential system, and results in a quieter vacuum toilet. The closure of the first valve22during the vacuum step that transfers the waste a longer distance provides a sound buffer for the second stage of the flush.

It is also envisaged that the two-stage flush mechanism may facilitate lavatory odor reduction and/or elimination of lavatory odor by providing an odor removal system26. In this embodiment, the odor removal system comprises an odor removal line28, an air muffler30, and a valve32for odor removal. (Alternatively, valve32for odor removal may be provided as a multi-port valve100that combines the function of second stage flush valve24and odor removal valve32, as discussed below. This is illustrated byFIG. 8.) If this odor removal feature is provided, the valve32is configured to open during the second stage of the flush. In a specific embodiment, both the second and third valves (24,32) open simultaneously for the second stage. Odor is extracted through the odor removal line28via the air muffler30. The air muffler vents air away from the lavatory. The muffler30may function to deliver air out of the lavatory and pull it into the odor removal line28, which ultimately leads to the main waste lines16. In the embodiment shown, the muffler30/air odor removal line28pulls air from the lavatory through the muffler30and then into the transient tank20, continuing onto the main waste line16and main waste tank18during the flush cycle. In an alternate embodiment (not shown), the muffler30/air odor removal line28pulls air from the lavatory through the muffler30straight to the main waste line16(and continuing onto the main waste tank18during the flush cycle.)

Without air muffler30, the air would whistle through the lavatory, and the muffler helps silence the extraction of air through the odor removal system26. A perspective view of this system is illustrated byFIG. 3.

It is important to note that althoughFIGS. 1 and 2show the second valve24and the odor removal valve32as being two separate valves, it should be understood that they may be combined into a single multi-port valve100, as illustrated byFIG. 8. (One example of a multi-port valve that may be useable in connection with this invention is shown and described in the co-pending and co-assigned application titled “Multi-Port Orbital Valve,” U.S. Ser. No. 61/714,912, filed Oct. 17, 2012.) This valve allows the two valves to open and/or close at the same time or otherwise as desired.

Once the flush cycle has been completed, valve(s)24and/or32close, and the entire system is again under vacuum. The second stage of the flush restores vacuum to the transient tank20so that it is also ready for another flush.

Although this two-stage flush system may be used with fresh water or other water circulated on-board the aircraft, it is understood that the use of fresh water for toilet flushing purposes is wasteful if spent or grey water can be used. Accordingly, it is possible to provide a grey water reservoir34that can deliver flush water to the toilet bowl13. As shown inFIG. 1, the grey water reservoir34is generally positioned between the wash basin12and the vacuum toilet bowl14. Reservoir34is in fluid communication with the wash basin12, such that spent water from hand washing is collected in the reservoir34. This reservoir34may be any appropriate size, although in one embodiment, it is sized small enough to fit underneath the wash basin12without taking up a great deal of lavatory space. Accordingly, if excess water is collected in the reservoir34past its capacity without it being used for toilet flush water as described below, overflow provisions are provided. In a particular embodiment, reservoir34has approximately a one liter capacity, although smaller and larger options may be provided. The reservoir is shown in the figures as being a generally rectangular container, but it should be understood that any shape or configuration is possible and within the scope of this invention.

The reservoir34is in fluid communication with the wash basin12via conduit36. As shown inFIG. 4, conduit36may be secured to an inlet38of the reservoir34. This allows spent water from the sink to be delivered to and captured in the reservoir34. A water level sensor40is provided on or otherwise associated with the reservoir34, which indicates the amount of water that the reservoir34currently holds. If the sensor40detects that the water level in the reservoir34is so low that it does not contain sufficient grey water to support the next flush cycle, then water may be delivered to the reservoir34via a connection to the aircraft main water tank and/or by opening and shutting the faucet. (Although these connections are not shown by the Figures, it is understood that an additional line from the potable water line42that delivers water to the faucet44may be routed to the reservoir34.)

If the sensor40detects that the water level in the reservoir34is so high that it may backflow back into the wash basin12, then an overflow system may be activated to prevent flooding. In one embodiment, overflow system includes a purge valve46(or pinch valve) that may be activated to deliver the excess grey water out of an outlet48in the reservoir to the main waste line16. Typically, the water exiting through outlet48is unfiltered or untreated grey water. When the purge or pinch valve opens, the vacuum in the toilet system causes the excess water to rush out of the reservoir34into the main line16and/or main waste tank18. (When the water sensor40senses that the water level is low, the pinch valve closes, causing water to accumulate in the reservoir34as desired.) In another embodiment, the overflow system may discharge excess grey water directly into the toilet or into the transient tank20on the next flush cycle.

The water sensor40may be a pressure-based sensor, a capacitance-based sensor, or any other appropriate sensor sufficient to detect the presence or absence of water in the reservoir34. In one embodiment, it may be useful to use a sensor that has a probe that is not in direct contact with the water, as any debris in the water (such as detergents, particulates, or bacteria) can create false readings and be more difficult to maintain and/or clean.

If neither a high nor a low condition is sensed by the water level sensor40, then normal operation of the grey water in the reservoir34for use as flush water may follow. In one embodiment, the system includes a spent (or grey) water treatment system. The spent water treatment system is generally provided to ensure that the water being held in reservoir34is not contaminated when it is used for flush water. (During the toilet flush, water particles can spray into the air. Although the flush water need not be potable, it is desirable that the flush water be free from particulates, pathogens, and other potential bacteria or contaminants. It is also desirable that the flush water be treated so that it does not damage the toilet components or cause discoloration of the toilet bowl14.)

Accordingly, the spent water treatment system may include a filter50that removes small suspended materials, such as particulates in the water. Filter50may also have anti-microbial properties. The filter50may be positioned in the reservoir34in any appropriate manner.FIG. 4shows a replaceable filter that is angled in the reservoir.FIGS. 5 and 6show a cylindrical filter, which may be a cylindrical replaceable filter cartridge. This first filter step is intended to remove particulates (and possibly some pathogens) from the grey water, and any appropriate filter designed for such purpose is possible for use.

Additionally and/or alternatively, an ultraviolet (UV) light treatment step may be conducted, for eradication of microbiological contamination. This UV treatment may occur inside the reservoir, although it may also occur as a separate treatment in chamber52, as shown inFIGS. 1 and 2, as the water is being delivered to the toilet bowl14. As shown, UV chamber may be connected in-line with the reservoir34. Non-limiting examples of various types of UV treatment that may be used for this treatment are described in co-pending and co-assigned applications titled “Inline UV LED Water Disinfection and Heating,” U.S. Ser. No. 13/707,808, filed Dec. 7, 2012, as well as co-pending and co-assigned applications titled “Systems and Methods for Disinfecting Water,” filed Aug. 31, 2010 and published as U.S. 2012/0051977.

Additionally and/or alternatively, a chemical treatment may be conducted on the grey water prior to its use as flush water. In one embodiment, a chemical reservoir54is provided as shown inFIG. 5, which can deliver appropriate and/or periodic chemical treatment or disinfectants to the grey water contained in the reservoir34. Once the grey water has been sufficiently treated in order to meet required or desired regulations, it is ready for delivery to the toilet bowl14as flush water for use when a flush sequence is triggered. (It is possible that the some or all of the water treatment does not occur until the water is need for a flush sequence and is caused to be routed through a filter50and/or a UV chamber52and/or receives a chemical treatment54as it leaves reservoir34.)

When a flush sequence is activated, a pump56may be activated to pull water through an outlet58in the reservoir34, and to deliver the water to the toilet bowl14for a flush sequence. As an initial matter, the valves of the multi-valve flush system are all closed and the system is under vacuum pressure. As shown inFIG. 7, the toilet bowl has a rinse inlet60, to which the cleaned grey water is delivered. The flush sequence then follows the two-stage flush sequence described above. Specifically, the first valve22between the toilet bowl14and the transient waste tank20opens and functions to deliver the waste to transient tank20during the first stage of the flush. Other valve(s) remain closed during the first stage. During the second stage of the flush, the first flush valve22closes, which prevents any transfer of vacuum to the toilet bowl14. The second valve24(typically opened simultaneously or nearly simultaneously with the odor removal valve32) is then opened and functions to deliver the waste through tank outlet62to the waste holding tank18. The odor removal valve32also causes air to be pulled into the odor removal line28.

The time between the first and second stage is generally very short and can be anywhere from a few milliseconds, to a few seconds, but should generally be shorter than a few minutes. The primary intent is that the first valve22is not opened at the same time that the valve(s) located further downstream are open.FIG. 7also shows an embodiment of the system that has a connection/conduit64on the transient tank20which is fluidly connected to outlet58on reservoir34for draining grey water from the reservoir34into the transient tank20.FIG. 7also illustrates an optional vacuum gauge66that can be used to monitor the vacuum level in the tank20and aid in controlling the flush cycle.

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 invention and the following claims.