Abstract:
Vacuum toilet assemblies are detailed. These assemblies are designed to reduce both operational noise and water usage of the toilets while continuing to promote effective disposal of waste. They also require less air for operation than do conventional vacuum toilets.

Description:
FIELD OF THE INVENTION  
       [0001]     This invention relates to waste disposal and more particularly, but not necessarily exclusively, to vacuum toilet assemblies preferably used in vehicles such as airplanes.  
       BACKGROUND OF THE INVENTION  
       [0002]     U.S. Pat. No. 6,401,270 to Moore, incorporated herein in its entirety by this reference, discloses a conventional hydraulic toilet in which positive pressure is used to facilitate discharging waste from a toilet pan or bowl. A closeable lid may be sealed to the bowl to define a chamber, with an air displacement unit connected to the chamber utilized to increase air pressure therein. The toilet of the Moore patent is not a vacuum type, however, and the Moore patent neither contemplates nor suggests means for reducing noise associated with operation of the toilet.  
         [0003]     Unlike the Moore patent, U.S. Pat. No. to Olin, et al. (also incorporated herein in its entirety by reference) does detail a vacuum-type toilet. According to the Olin patent, operational noise of the toilet may be diminished through use of “a lid forming a substantially airtight and soundproof closure at the top of the bowl.” See Olin, Abstract, 11. 15-17. Air may be supplied to the toilet bowl via a tube or pipe entering at the back thereof if closing the lid results in too little air being present in the bowl for efficient flushing of waste. The Olin patent does not, however, address reducing water consumption in such a toilet design.  
       SUMMARY OF THE INVENTION  
       [0004]     The present invention is intended to reduce both operational noise and water usage of a vacuum-type toilet while continuing to promote effective disposal of waste. It also allows for the amount of air per flush to be regulated compared to conventional vacuum toilets. In passenger aircraft, for example, reducing the amount of air required for toilet operation commensurately reduces the amount of cabin air necessarily replaced following use of the toilet. Because air has tendency to dry waste, using less air may also promote overall waste-system hygiene by reducing build-up of solids in waste-disposal piping.  
         [0005]     Included as components of a toilet assembly of the present invention are a bowl having a rim and a shroud to which a lid is fitted. When closed, the lid is designed to seal against the upper surface of the shroud. Magnetic switches or other suitable means communicating with the flush mechanism may be used to ensure the lid is closed before the toilet is flushed.  
         [0006]     Defined along the interior of the rim of the bowl may be a distribution “ring” at or through which both water and air may enter. Although preferably entering through separate openings in the distribution ring, the water and air combine upon entry into the bowl and are pulled through the bowl by evacuation thereof. Airflow pattern down the bowl face generates an “air knife” effect, which accelerates the water, in turn more efficiently removing waste from the bowl. This effect additionally reduces the overall amount of water needed to rinse the bowl effectively. In one presently-preferred embodiment, for example, only two and one half to three ounces of water may be needed for effective flushing.  
         [0007]     Further, closing the lid and sealing it against the shroud reduces the amount of air entering the waste system via the bowl. Together with having air enter via the distribution ring under the shroud of the bowl, this sealing greatly reduces the noise associated with flushing the toilet. In a preferred embodiment, noise levels of less than eighty-four decibels have been achieved. For vehicle-mounted toilets, closing and sealing the lid also prevents flushing noise from reflecting off internal panels of the associated lavatory and escaping through door vents so as to disturb other passengers.  
         [0008]     It thus is an optional, non-exclusive object of the present invention to provide improved vacuum-toilet assemblies.  
         [0009]     It is another optional, non-exclusive object of the present invention to provide vacuum toilets which reduce air flow into the toilet bowl, require less water for effective flushing, and diminish the overall noise volume associated with flushing the toilets.  
         [0010]     It is also an optional, non-exclusive object of the present invention to provide toilets in which lids seal with shrouds prior to flushing.  
         [0011]     It is a further optional, non-exclusive object of the present invention to provide vacuum toilets having a distribution ring located along the rims of the bowls under the shrouds.  
         [0012]     It is, moreover, an optional, non-exclusive object of the present invention to provide vacuum toilets in which both air and water enter the bowls via the distribution rings.  
         [0013]     It is yet another optional, non-exclusive object of the present invention to provide vacuum toilets in which evacuation of the bowls produces an air-knife effect.  
         [0014]     Other objects, features, and advantages of the present invention will be apparent to those skilled in the relevant field with reference to the remaining text and drawings of this application. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]      FIG. 1  is a partially-schematicized view of an exemplary vacuum-toilet assembly of the present invention.  
         [0016]      FIG. 2  is a cross-sectional view of a portion of the toilet assembly of  FIG. 1 . 
     
    
     DETAILED DESCRIPTION  
       [0017]     Illustrated in  FIGS. 1-2  are aspects of toilet assembly  10  of the present invention. Included as part of assembly  10  may be toilet bowl  14 , flush valve  18 , and lid  22 . Additionally included may be shroud  26 , which in use typically surrounds the periphery of bowl  14  at or adjacent (and slightly above) rim  30 . Assembly  10  advantageously is of the vacuum type, in which waste is removed from bowl  14  by evacuating it. Assembly  10  additionally is especially designed for use in passenger aircraft, although it may function suitably in other vehicles, in buildings, or in other locations or objects as well.  
         [0018]     Assembly  10  may include some or all of the valves, ducts, and other components described in the Olin patent. Beneficially, however, bowl  14  defines distribution ring  34 , preferably located within the bowl  14  at rim  30 . Both water and air may enter bowl  14  at ring  34 , promoting good mixing of the water and air upon entry into the bowl  14 .  
         [0019]     Water may be supplied to bowl  14  in conventional ways, including via a pipe designed to discharge the water along ring  34 . Air preferably enters bowl  14  through at least one (and beneficially multiple) openings  38  through the wall of bowl  14  at rim  30 . Such openings  38  are below the level of shroud  26 , thereby limiting the amount of air available to them. Openings  38  are, however, at approximately the level of the water entering bowl  14 , allowing immediate mixing of the water and air at a point well above bottom section  42  of the bowl  14 .  
         [0020]     Either or both of lid  22  and shroud  26  may include sealing material such as gasket  46 . Although any suitable sealing material or mechanism may be employed, gasket  46  functions to create an air-impervious seal between lid  22  and shroud  26  and prevent air from above shroud  26  entering bowl  14  through main waste-receiving opening  50  when the lid  22  is closed (as shown in  FIGS. 1-2 ). Although not illustrated in  FIGS. 1-2 , assembly  10  additionally may, if desired, comprise a magnetic switch or other mechanism designed to communicate with valve  18  and prevent flushing of bowl  14  unless lid  22  is closed. One such approach could employ a magnet placed in lid  22  and a corresponding magnetic switch placed under shroud  26 . Another example could include an automatically-closing lid  22  which could be activated via an infrared sensor or otherwise so as to be hands-free.  
         [0021]     When assembly  10  is flushed, water and air enter bowl  14  at distribution ring  34 , are mixed, and are pulled toward bottom section  42  as bowl  14  evacuates. Air flow patterns across the interior face of bowl  14  generate an “air knife” effect, accelerating the flow of the water. Increased force applied to the water provides a more efficient way of removing waste within bowl  14 . This effect also reduces the overall amount of water needed to rinse bowl  14  effectively. Indeed, some embodiments of assembly  10  require only approximately two and one half to three ounces of water to flush satisfactorily, significantly less water than used by vacuum toilets currently employed on aircraft.  
         [0022]     Because lid  22  is closed during flushing of assembly  10 , the amount of air pulled through bowl  14  during the flush may be regulated (depending on the number and size of openings  38 ). Further, because lid  22  is closed and air is pulled from areas below shroud  26 , the noise associated with the flush is substantially reduced. Although lid  22  is likely subjected to greater pressure than ambient (e.g. than aircraft cabin pressure) when assembly  10  is flushed, such pressure differential is only approximately two to four inches of mercury, within the stress capabilities of existing lids.  
         [0023]     The foregoing is provided for purposes of illustrating, explaining, and describing exemplary embodiments and certain benefits of the present invention. Modifications and adaptations to the illustrated and described embodiments will be apparent to those skilled in the relevant art and may be made without departing from the scope or spirit of the invention.