Abstract:
An apparatus is provided for selecting either potable water or seawater as flush water for marine sanitary toilets. The apparatus may be designed to be electrically or manually operated. Check valves and vaccum breaker prevent contamination or waste of the potable water supply.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an apparatus for selecting among multiple sources of flush water for a toilet, such as a marine toilet, while avoiding contamination of the flush water sources. The multiple sources of flush water for a marine toilet may include potable water and may include seawater. For the purposes of this application, the term “seawater” means any water in which the vessel floats, whether the water is lake or salt. 
     2. Description of the Prior Art 
     The design of sewage systems for use aboard marine vessels presents a tension between aesthetics and space limitations. Odor is always an issue concerning sewage disposal, and the use of potable water for flushing waste from toilets is preferred to other flushing media such as recirculated wastewater or seawater due to the lower potential for odor presented by potable water. However, space to store potable water is scarce on a marine vessel. It is desirable, therefore, to use a source other than potable water to flush wastes from a marine toilet while a vessel is away from port. In port, a vessel may be connected to a land-based potable water system and the need to conserve potable water is reduced. 
     The present invention provides that the flushing medium readily may be selected either as seawater or as potable water. The invention allows the avoidance of unnecessary odor in port, where an ample supply of potable water is available, and allows a vessel to avoid storage of unnecessary quantities of potable water while away from port. 
     Toilets used in marine vessels such as personal yachts and pleasure craft typically utilize either manual or electrical pumps to supply a source of flush water. Popular models of electrically operated marine toilets include (but not limited to) the Atlantes™ and Crown Head II™ and rely upon flush water supplied to the toilet under pressure by an electrically operated pump. Manual toilets may use a manually operated piston pump to pump seawater into the toilet and sewage out of the toilet. In the piston pump toilets, one side of the pump piston is used to supply a positive pressure to pump the seawater into the toilet bowl. The second side of the pump piston is used to supply a negative pressure to the sewage in the toilet bowl, clearing the bowl and allowing the sewage to flow to a holding tank. 
     Toilets used in marine vessels generally use either potable water or seawater to flush waste from the toilet bowl and into holding tanks or treatment system. The flush water and the collected wastes are removed from the holding tanks when the vessel is in port. The prior art toilets and marine sewage systems do not allow selection between seawater and potable water as flushing media. The prior art toilets and marine sewage systems therefore are susceptible to the odor and potable water storage deficiencies discussed above. 
     Several devices have been developed to address these problems. U.S. Pat. No. 3,593,346 to Katona issued Jul. 20, 1970 provides for the selectable use of recirculated sewage or potable water as flushing media for vehicle toilets. Recirculation of sewage, while space-efficient, exacerbates the problem of odor. The 346 Katona patent does not provide for selecting either seawater or potable water as the flushing media. 
     U.S. Pat. No. 3,611,447 to Howard, issued Oct. 12, 1971 addresses the odor problem caused by recirculated sewage used as flush water. Howard provides two sequential toilet bowls separated by valves. The first bowl is flushed with potable water and the second is flushed with recirculated sewage. Howard does not provide for selecting either seawater or potable water as the flushing media. 
     U.S. Pat. No. 3,780,383 to Katona issued Dec. 25, 1973 is based on a divisional application and includes the same disclosure as the 346 Katona patent. The 383 Katona patent teaches a folding toilet with a bowl that drains into a second bowl when the toilet is folded. Both bowls are flushed selectively with treated wastewater or “running water.” The 383 Katona patent does not provide for selecting either seawater or potable water as the flushing media. 
     U.S. Pat. No. 3,815,159 to Delaney issued Jun. 11, 1974 and related U.S. Pat. No. 3,927,425 to Delaney issued Dec. 23, 1975 reveal a sewage system for marine vessels using recirculated treated sewage for the flushing of toilets. The Delaney patents do not provide for selective use of seawater or potable water as the flushing media. 
     U.S. Pat. No. 4,433,443 to DeGraw issued Feb. 28, 1984 reveals a marine sewage system using seawater for flushing of toilets. A removable filter cassette collects solid wastes from the seawater and the contaminated seawater is treated by an “electrolytic cell.” The treated seawater is then discharged to the sea. DeGraw does not provide for selection between seawater and potable water for the flushing of toilets. 
     U.S. Pat. No. 4,454,613 to Palmer reveals a sewage system for travel trailers and allows flushing of toilets using either potable water or non-sewage wastewater. Palmer does not teach selectable use of seawater or potable water for flushing of toilets. 
     U.S. Pat. No. 5,711,038 to Neithammer dated Jan. 27, 1998 reveals a toilet for vehicles where solid wastes are separated from liquid wastes, the liquid wastes are disinfected and used for flushing toilets. Neithammer does not teach selectable use of seawater or potable water for flushing toilets. 
     The apparatus of the present invention offers advantages over the prior art. The prior art marine sewage systems neither teach nor suggest the selectable use of seawater or potable water as a flushing media. The prior marine sewage systems do not teach or suggest the use of the valving and related system of the present invention to allow selectable interconnection of seawater systems and potable water systems for the flushing of toilets while avoiding contamination of either system. 
     SUMMARY OF THE INVENTION 
     The apparatus of the present invention allows selection of either seawater or potable water for flushing one or more toilets on a marine vessel. The selection of potable water as the flushing water allows prevention of odors while a vessel is in port and potable water is plentiful. The selection of seawater as the flushing water allows for the conservation of scarce potable water while the vessel is away from port. The selectable use of sea water or potable water also provides redundancy and a reliable supply of toilet flush water in the event that one source or the other should fail to function. 
     The selection between seawater and potable water may be effected either electrically or manually, or by a combination of the two methods. When the selection is accomplished electrically, the selection may be effected by the operation of a single electrical switch. The electrical switch energizes electrical circuits for appropriate solenoid valves and pumps. The activated solenoid valves open a hydraulic path to the selected flush water. The energized pump circuit is available to pump the selected flush water to the toilet when activated by the person using the toilet. Redundant check valves prevent contamination of the potable water supply by seawater. An appropriate atmospheric vacuum breaker prevents contamination of the flush water supply lines by seawater. If the toilet is installed below the water line of a vessel, an appropriate vented loop prevents overflow of the toilet from the static pressure of the seawater when seawater is selected as the flush water. An appropriate strainer may be installed on the seawater intake line to remove objects from the seawater and to reduce odors and deposits in the toilet. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a plumbing diagram of the preferred embodiment where the toilet is installed above the water line of a marine vessel. 
     FIG. 2 is a plumbing diagram of the preferred embodiment where the toilet is installed below the water line of a marine vessel. 
     FIG. 3 is wiring diagram for a typical installation of the apparatus using an electrically operated toilet. 
     FIG. 4 is a plumbing diagram of an alternative embodiment where a manually-operated marine toilet is installed above the water line of a marine vessel. 
     FIG. 5 is a detail of a manual pedal-operated potable water valve and check valve assembly. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 is a plumbing diagram of the preferred embodiment. In FIG. 1, a marine vessel  2  floats in seawater  4 . A marine toilet  6 , such as the Atlantes™ or Crown Head II™, is mounted above the waterline  8  as determined by the angle of maximum heel of the vessel  2 . The toilet  6  discharges sewage  16  to a toilet discharge line  10  and hence to a sewage holding tank  12 . Sewage  16  is pumped from the holding tank  12  when the vessel  2  is in port and disposed in a land-based sewage treatment system. 
     Flush water  14 , selectably comprising either seawater  4  or potable water  18 , is delivered to the toilet  6  through a flush water supply line  20 . A vacuum breaker  22  prevents a vacuum from drawing sewage  16  from the toilet  6  and contaminating potable water  18  or seawater  4 . A vacuum breaker supply line  24  transmits the flush water  14  from “T” connector  26 . 
     When potable water  18  is selected, potable water “T” connector supply line  28  transmits potable water  18  from a first potable water check valve  30  to “T” connector  26 . The first potable water check valve  30  prevents flow of either sewage  16  or seawater  4  to potable water supply  44  and prevents contamination of potable water  18 . Second potable water check valve  32  is connected in series with first potable water check valve  30  and provides redundant protection from contamination of potable water  18 . 
     A potable water check valve supply line  34  transmits potable water  18  from the potable water valve  36  to the second potable water check valve  32 . The potable water valve  36  preferably is electrically activated as discussed below concerning FIG. 3 to select or to deselect potable water  18  as the flush water  14 . The potable water valve  36  when in the closed position provides redundancy to prevent contamination of potable water  18  by sewage  16  or by seawater  4 . 
     A potable water valve supply line  38  transmits potable water  18  from a potable water shutoff valve  40  to the potable water valve  36 . The potable water shutoff valve  40  provides a manual means for shutting off the flow of potable water  18 . A potable water shutoff valve supply line  42  transmits potable water  18  from the pressurized source of potable water  44  to the potable water shutoff valve  40 . 
     A seawater pump discharge line  46  transmits seawater  4  from the seawater pump  48  to the “T” connector  26  when seawater  4  is selected as the flush water  14 . When seawater  4  is selected as the flush water  14  as described below and illustrated by FIG. 3, the seawater pump  48  provides pressure to pump seawater  4  to the toilet  6 . A seawater pump supply line  50  transmits seawater  4  from the seawater strainer  52  to the seawater pump  48 . The seawater strainer  52  removes debris from the seawater  4  to reduce odor and staining of the toilet  6 . 
     A seawater strainer supply line  54  transmits seawater  4  from the seawater check valve  56  to the seawater strainer  52 . The seawater check valve  56  prevents the loss of potable water  18  when potable water  18  is selected as the flush water  14 . 
     Seawater check valve supply line  58  transmits seawater  4  from seacock  60  to seawater check valve  56 . Seacock  60  allows the seawater  4  to be manually shut off. A seacock supply line  62  transmits seawater  4  from the seawater intake  64  to the seacock  60 . 
     All water supply lines are preferably flexible tubing three quarters of an inch in diameter. Each end of each water line is preferably secured using tubing clamps. 
     FIG. 2 is a plumbing diagram of the preferred embodiment where the marine toilet  6  is installed below the waterline  8  of the vessel  2 . In this embodiment, the vacuum breaker supply line  24  transmits flush water  14  from a vented loop  66  to the vacuum breaker  22 . The vented loop  66  includes a vent tube  68 . The vented loop  66  and vent tube  68  ensure that the static pressure of the seawater  4  does not cause seawater  4  to continually flow into the toilet  6  when the toilet  6  is below the waterline  8 . A vented loop supply line  70  transmits the selected flush water  14  from the “T” connection to the vented loop  66 . In other respects, the embodiment of FIG. 2 is identical to that of FIG.  1 . 
     FIG. 3 shows a typical wiring diagram of the preferred embodiment. A flush water selector switch  72  is provided having two positions. A normally open toilet activation switch  74  also is provided. When the flush water selector switch  72  is in a first position  98  and the toilet activation switch  74  is simultaneously closed, an electrical circuit is completed between power supply  76  and potable water valve  36 . Electrical power flowing through the circuit opens potable water valve  36  using a solenoid or by any other suitable means. Potable water  18  flows from the pressurized potable water supply  44  through the open potable water valve  36 , through the first and second potable water check valves  30 ,  32 , through the “T” connector  26 , through the vacuum breaker  22 , and to the toilet  6  as flush water  14 . Potable water  18  is prevented by the seawater check valve  56  from flowing through the seawater pump  48  and out the seawater intake  64 . 
     When the flush water selector switch  72  is in the second position  96  and the toilet  6  actuation switch is simultaneously closed, a normally open relay  78  is energized by a power supply  76 . The relay  78  is then closed, completing an electrical circuit between the power supply  76  and the seawater pump  48 . The seawater pump  48  is thus activated, pumping seawater  4  from the seawater intake  64  through the seawater check valve  56  and seawater strainer  52 , through the “T” connector  26 , through the vacuum breaker  22  and to the toilet  6  as flush water  14 . The seawater  4  is prevented from entering the potable water supply  44  by the first and second potable water  18  check valves and by the potable water valve  36 . The normally open relay  78  is protected by a fuse  80 . 
     FIG. 4 illustrates an alternative embodiment utilizing a manual marine toilet  82  in an installation above the waterline  8  of a vessel  2 . A manual toilet  82  discharges sewage  16  through a toilet discharge line  10  to a sewage holding tank  12 . A flush water supply line  20  transmits selected flush water  14 , either seawater  4  or potable water  18 , from a vacuum breaker  22 . A vacuum breaker supply line  24  transmits selected flush water  14  from a “T” connector  26  to the vacuum breaker  22 . 
     To select seawater  4  as the flush water  14 , a flush-to-dry valve  84  is opened to allow flow of seawater  4 . A manual pump lever  86  is operated to activate a manual pump  88 . The manual pump  88  draws seawater  4  through a seawater intake  64 , through a seawater intake  64  line, through the flush-to-dry valve  84  and into the manual pump  88 . The seawater  4  is then forced under pressure through a manual seawater pump check valve  94 , through a seawater pump discharge line  46  to the “T” connector  26 , through the vacuum breaker  22 , through the toilet  6  supply line and into the toilet  6  as flush water  14 . 
     To select potable water  18  as the flush water  14  in the manual toilet  82  embodiment of FIG. 4, a pedal-operated water valve  90  is provided. As shown by FIG. 5, the pedal-operated water valve  90  is an assembly including a pedal  100 , a manual potable water valve  92  operated by the pedal  100 , a first potable water check valve  30  and a second potable water check valve  32 . Depression of the pedal  100  opens the potable water valve  92  allowing potable water  18  to flow from the pressurized potable water supply  44  through the first and second potable water check valves  30  and  32  and hence to the “T” connector  26  (FIG.  4 ). Potable water  18  flows through the “T” connector  26 , through the vacuum breaker  22 , through the flush water supply line  20  and to the manual toilet  82  as flush water  14 . 
     In the preferred embodiment of FIG. 4, the manual pump  88  is a compound pump, which is well known in the art of manual marine toilets  82 . One side of the piston of the manual pump  88  serves to pump seawater  4 . The other side of the piston pumps sewage  16  from the manual toilet  82 . When potable water  18  is selected as flush water  14 , the manual pump  88  is operated to clear sewage  16  from the manual toilet  82 . To prevent the manual pump  88  from attempting to pump seawater  4  when potable water  18  is selected, the flush-to-dry valve  84  is closed, preventing seawater  4  from entering the pump  88  and venting the seawater side of the pump  88  to the atmosphere. 
     The present invention utilizes a pressurized potable water supply  44 . The potable water supply  44  may be pressurized by any of the methods known in the art, including use of an electrical pump or elevating the potable water supply  44 .