Patent Publication Number: US-11021863-B2

Title: Pre-primed siphonic toilet

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a Continuation of U.S. patent application Ser. No. 15/981,457, filed May 16, 2018, which is a Divisional of U.S. patent application Ser. No. 15/360,434, filed Nov. 23, 2016 (and granted as U.S. Pat. No. 9,988,802 on Jun. 5, 2018). Each of the aforementioned U.S. patent applications is incorporated by reference herein in its entirety. 
    
    
     BACKGROUND 
     The present application relates generally to the field of siphonic toilets. More specifically, this application relates to a siphonic toilet and methods of flushing such siphonic toilets that involves pre-priming a passageway prior to a flush cycle to improve the siphon during the flush cycle. 
     SUMMARY 
     At least one embodiment relates to a siphonic toilet that includes a bowl, a passageway, an inlet, and a valve. The passageway includes an entrance, an outlet, and a dam located between the entrance and the outlet. The entrance is fluidly connected to the bowl, and the bowl and the dam are configured to hold a first volume of water prior to a flush cycle of the toilet. The inlet is located in the passageway downstream from the dam, and the inlet is configured to introduce water into the passageway downstream from the dam. The valve is located between the inlet and the outlet of the passageway, and the valve retains a second volume of water in a closed position prior to the flush cycle to affect a siphon during the flush cycle. The valve can be any type of valve that retains water and release water on command. 
     At least one embodiment relates to a siphonic toilet that includes a passageway and a valve. The passageway is fluidly connected to a bowl, and the passageway includes an up leg and an outlet leg. The up leg extends from the bowl to a dam so that a first volume of water is retained in the up leg and the bowl prior to a flush cycle of the toilet. The outlet leg extends from the dam toward an outlet. The valve is located between the up leg of the passageway and the outlet, and the valve is configured to retain a second volume of water (when the valve is) in a closed position (e.g., prior to the flush cycle of the toilet) to affect a siphon during the flush cycle. The passageway may (e.g., optionally) include an inlet in the passageway, where the inlet is disposed in the passageway downstream from the dam to introduce the second volume of water into the passageway downstream from the dam. 
     At least one embodiment relates to a method of flushing a siphonic toilet. The method includes retaining a first volume of water in a bowl and an up leg of a passageway that is upstream from a dam. The method includes retaining a second volume of water in the passageway between a valve and the dam with the valve in a closed position. The method includes activating a flush cycle of the toilet that introduces a third volume of water into the bowl, and moving the valve from the closed position to an open position to affect a siphon during the flush cycle. 
     The second volume of water may be introduced into the passageway using a flow control device prior to activating the flush cycle through an inlet located downstream of the dam and upstream from the valve. 
     The method may include venting (e.g., releasing) air through an air pressure release line extending between a first opening in the passageway and a second opening in the passageway. The first opening may be located upstream from the inlet and downstream of the dam. The second opening may be located downstream of the valve. The valve may be configured to seal off the second opening, such as when the valve is in the open position. The valve may be configured to expose the opening, such as when the valve is in the closed position. 
     At least one embodiment relates to a method of flushing a siphonic toilet that includes retaining a first volume of water upstream of a dam of a passageway, which fluidly connects an outlet of a bowl and an outlet of the siphonic toilet; retaining a second volume of water in the passageway downstream of the dam through a valve located between the dam and the outlet of the siphonic toilet; activating a flush cycle that introduces a third volume of water into at least one of the bowl and the passageway; and moving the valve from a closed position to an open position to affect a siphon during the flush cycle. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an exemplary embodiment of a pre-primed siphonic toilet. 
         FIG. 2  is a schematic side view of the toilet shown in  FIG. 1 . 
         FIG. 3  is a perspective view of another exemplary embodiment of a pre-primed siphonic toilet. 
         FIG. 4  is a cut-away side view of the toilet shown in  FIG. 3 . 
         FIG. 5  is a cross-sectional side view of an exemplary embodiment of a passageway for use in a pre-primed siphonic toilet. 
         FIG. 6  is a cross-sectional side view of another exemplary embodiment of a passageway for use in a pre-primed siphonic toilet. 
         FIG. 7  is a cross-sectional side view of another exemplary embodiment of a passageway for use in a pre-primed siphonic toilet. 
         FIG. 8  is a perspective side view of another exemplary embodiment of a passageway for use in a pre-primed siphonic toilet. 
         FIG. 9  is a perspective side view of yet another exemplary embodiment of a passageway for use in a pre-primed siphonic toilet. 
         FIG. 10  is a cross-sectional side view of another exemplary embodiment of a passageway and a bowl of a pre-primed siphonic toilet. 
         FIG. 11  is a cross-sectional side view of another exemplary embodiment of a passageway and a bowl of a pre-primed siphonic toilet. 
         FIG. 12  is a cross-sectional side view of another exemplary embodiment of a passageway, a bowl and a drain pipe of a pre-primed siphonic toilet. 
     
    
    
     DETAILED DESCRIPTION 
     Referring generally to the Figures, disclosed in this application are siphonic toilets that are pre-primed prior to a flush cycle to improve the siphon during the flush cycle. As discussed below in more detail, the toilets of this application may advantageously be configured, for example, to use less water during a flush cycle and/or decrease the time it takes to complete a flush cycle. The toilets may advantageously be configured to eliminate the need for a tank containing the water, which reduces cost and the size of the toilet. The performance of toilets of this application advantageously are not affected by changes in line pressure, unlike tankless toilets operating purely on line pressure (e.g., household line pressure), which can vary by 10 psi or more. This advantageously allows the toilets of this application to eliminate the use of electric pumps, which are used to increase line pressure. 
     For example, the toilets of this application improve how the siphon is created/induced, such as by pre-priming the siphon before each flush cycle is activated. A volume of water is introduced into a passageway (e.g., trapway, trap, etc.) of the toilet, and the water remains in the passageway until a user flushes the toilet (e.g., activates a flush cycle). Other siphonic toilets prime the siphon after the flush cycle is activated by introducing water directly into the bowl, which then must make its way (e.g. flow) to the trap at a flow rate that is greater than a threshold in order for a siphon to occur. One problem with these toilets is that waste can block the opening to the trapway and impede the siphon by reducing the flow of water from the bowl to the trapway below the threshold, which in-turn reduces the effectiveness of the flush. 
     The toilets disclosed in this application include a passageway with a valve (e.g., located proximate an outlet of the passageway) for pre-priming the system. As used herein, the term “pre-prime” denotes that the water is introduced into the passageway in advance of (e.g., prior to, before, etc.) activation of a flush cycle, as opposed to “priming” which is performed after activation (e.g., initiation) of a flush cycle. Thus, the systems disclosed herein hold the pre-primed water in the passageway and, therefore, remain primed while the system is idle (i.e., between flush cycles). When the toilet is used (e.g., activated, flushed, etc.) and the system is actuated, a series of functions will initiate. According to an exemplary embodiment, actuating a flush cycle triggers water to flow from the rim or one or more rim jets for a predetermined amount of time, the valve in the passageway opens (e.g., after the predetermined amount of time), the mixture of waste and water is expelled from the system, then the valve closes, and the system refills the bowl with a first volume of water and pre-primes the passageway with a second volume of water for the next flush cycle. 
     According to another exemplary embodiment, the system can be integrated with a “grey water” system. The term “grey water” as used herein includes sources of water other than fresh water (e.g., clean water, potable water that is typically safe for consumption by people and may be subject to various regulations, treatment requirements, etc.), such as unpurified water that has been captured (e.g., rainwater, salt water, etc.), recycled water (e.g., used shower and/or bath water, dishwasher, clothes washer, etc.), and other sources of non-potable water (e.g., city sourced “purple pipe” non-potable water, etc.). For example, the term “grey water” as used herein includes, but is not limited to, unpurified water such as captured rainwater, recycled water from another appliance and/or plumbing fixture, such as a shower, bath, dishwasher, sink, washing machine, etc., and the like. Toilets that use grey water to feed the entire toilet system are not attractive to many consumers because the user is exposed to the sight and smell of the grey water, which is visible in the toilet bowl. Additionally, these toilets having grey water flowing through the whole system can require extra cleaning and maintenance. 
     The toilets disclosed in this application may be configured such that the user is not exposed to the grey-water. For example, the toilets herein may use grey water only to fill the passageway that is downstream of a dam (e.g., weir, etc.). Further, the toilets herein may be more environmentally friendly, such as by using less water (e.g., fresh water). The grey water introduced into the passageway downstream of the dam equates directly into less fresh water used during each flush cycle. Moreover, the toilets disclosed herein may be configured such that the bulk (e.g., majority) of water used during each flush cycle is introduced to pre-prime the flush cycle and, therefore, can be grey water. Thus, the toilets may be configured to use fresh water only for refilling and rinsing the bowl. The toilets of this application could reduce the usage of fresh water down to 0.25 gallons per flush, or even lower. For example, the toilets may be configured to use 0.25 gallons (or less) of fresh water and 1.0 gallon (or more) of grey water resulting in 1.25 gallons of total water per flush cycle. This is on par with or even better than current HET Water Sense® certified toilets, which function at 1.28 gallons per flush or less. This is also a 20% (twenty percent) reduction in water usage from the current government standard of 1.6 gallons per flush. 
     Attention to the figures will now be turned and a description of the embodiments disclosed therein will be provided. 
       FIGS. 1 and 2  illustrate an exemplary embodiment of a pre-primed siphonic toilet  101  that includes a bowl  103 , a passageway  104  (e.g., trapway, trap, waste conduit, etc.) fluidly connected to the bowl  103  and configured to transfer water and waste from the toilet  101 , and a valve  105  in the passageway  104  for retaining a volume of water in the passageway to pre-prime the toilet  101 . 
     The bowl  103  includes an inlet opening  131 , which may be defined by a rim of the toilet  101 . Waste may be introduced into the bowl  103  through the opening and water may be introduced into the bowl  103  through the rim or in another suitable way. The bowl  103  also includes a sump  133  at the bottom of the bowl  103  for retaining a volume (e.g., a first volume) of water, as well as any waste prior to a flush cycle.  FIG. 2  illustrates an exemplary embodiment of a fill line  135  (e.g., water line, etc.) to which water may be filled prior to flushing, such as by pre-priming a toilet that is configured for use with only fresh water (i.e., without grey water). The fill line  135  is above the height of the dam  143 , so the passageway could be pressurized to increase the height of the fill line above the dam without increasing the height of the water line in the passageway  104  to be higher than the height of the dam  143 . This arrangement may be advantageous, for example, if grey water is used to pre-prime the passageway  104  (e.g., to fill the outlet leg  145  or a portion thereof) to avoid commingling the grey water (in the outlet leg) and the fresh water (in the bowl and inlet leg).  FIG. 2  also illustrates another exemplary embodiment of a fill line  135 ′ to which water may be filled prior to flushing, such as, for example, if the toilet does not pressurize the passageway  104 . The fill line  135 ′ is configured to be no higher than the height of the dam  143  to avoid water from passing over the dam  143  from the inlet leg  144 . It should be noted that the systems, as disclosed herein, could be used to create a vacuum assist toilet. For example, with the valve closed, a vacuum could be induced, such as by increasing pressure in the system then opening the valve. 
     Water may be introduced into the bowl using one or more rim channel holes (e.g., openings, orifices, etc.), one or more jets, a combination of holes and jets, or any other suitable manner. The toilet  101  may include a flow control (e.g., the flow control  106 ) for controlling (e.g., metering) the water introduced into the bowl. 
     As shown best in  FIG. 2 , the passageway  104  includes a first end  141  (e.g., an entrance), which is fluidly connected to the bowl  103 , and a second end  142  (e.g., an outlet), which is configured to direct water and waste from the passageway and/or from the toilet, such as into a drain pipe. The passageway  104  includes a dam  143  that is located between the first and second ends  141 ,  142 . The dam  143  is elevated above (e.g., at a height that is higher relative to) the bottom of the bowl  103 , such that the dam  143  and the bowl  103  (e.g., the sump  133 ) hold (e.g., retain, store, etc.) a volume (e.g., first volume) of water (along with any waste) prior to a flush cycle of the toilet. 
     The passageway  104  may be configured having an inlet leg  144  (e.g., an up-leg) and an outlet leg  145 . The inlet leg  144  may extend from the bowl  103  to the dam  143 , such that the first volume of water is retained in the inlet leg  144  and the bowl  103  prior to a flush cycle of the toilet  101 . The outlet leg  145  may extend from the dam  143  toward an outlet, such as the outlet at the second end  142 . The outlet leg  145  may include a first portion  145   a  (e.g., a down leg) that extends generally downward from the dam  143  to a second portion  145   b  (e.g., a horizontal leg, a cross leg, etc.) that extends at an angle relative to the first portion  145   a . For example, the second portion  145   b  may be configured to extend generally horizontally, such that the second portion  145   b  is generally orthogonal to the first portion  145   a . As shown in  FIG. 2 , the valve  105  and the outlet (e.g., in the second end  142 ) are located in the second portion  145   b  of the outlet leg  145 . According to other examples, the passageways may have other configurations and the valve  105  may be located in the down leg and the outlet may be located in the down leg or the cross leg. 
     As shown in  FIG. 2 , the passageway  104  includes an inlet  147  into the passageway at a location that is upstream from the valve  105  and downstream from the dam  143  to introduce a volume of water (e.g., grey water, fresh water, etc.) into the outlet leg  145  of the passageway  104 . The volume of water introduced through the inlet  147  may be a second volume of water, which is used to pre-prime the toilet, such as when the first volume of water is retained in the inlet leg  144  and the bowl  103 . The inlet  147  may be located in an upper side (e.g., at the top) of the passageway  104  to utilize gravity to pull the water into the outlet leg  145 . It is noted that the passageway  104  does not have to include the inlet  147  and, according to other examples of passageways, the water retained by the valve  105  is introduced through the up leg of the passageway from the bowl. For example, the volume of water in the sump may be overfilled so that the excess water flows over the dam and into the passageway downstream of the dam to be retained by the valve. The inlet  147  is particularly advantageous for the system utilizing grey water, since locating the inlet  147  downstream of the dam contains the grey water in the waste side of the passageway (e.g., downstream of the dam) and prevents or prohibits the grey water from entering the bowl. 
     Also shown in  FIG. 2 , a fluid conduit connects a flow control to the inlet  147  to supply the pre-prime water into the passageway  104 . The flow control that supplies the pre-prime water may be the flow control  106  that supplies water to the bowl, such as for an embodiment utilizing fresh water in both the bowl and for the pre-priming. According to other examples, the flow control that supplies the pre-prime water may be a second flow control that is different than the flow control  106  (which may be a first flow control) that supplies water to the bowl. For example, the second flow control may be configured to supply grey water to pre-prime the passageway  104 , and the first flow control may be configured to supply fresh water to the bowl  103 . 
     The valve  105  is located in the passageway  104  and is configured to move (e.g., pivot, rotate, slide, translate, etc.) between a closed position and an open position. As shown best in  FIG. 2 , the valve  105  includes a flapper  151  that rotates by a predetermined angle about a pivot  152  between the open and closed positions. In the closed position, the valve  105  retains the pre-prime water (e.g., the second volume of water) in the passageway  104  for use during the next flush cycle. Thus, the flapper  151  is sized to seal off the opening in the passageway  104  through which the water and waste flow. Water and waste are free to flow through the passageway  104  and out the outlet (e.g., at the second end  142 ) when the valve  105  is in the open position. The valve  105  is opened to affect a siphon during the flush cycle of the toilet  101 . 
     As shown in  FIG. 2 , the valve  105  is located in the second portion  145   b  of the outlet leg  145  of the passageway  104 . The valve  105  may be located proximate to the outlet (e.g., at the second end  142 ). This arrangement may advantageously allow for the passageway  104  to hold additional water (e.g., grey water, fresh water) due to the expanded volume to affect a siphon relatively soon after initiation of (e.g., activating) a flush cycle. According to the examples in which the valve  105  is located in a cross leg that extend generally horizontally, the valve  105  (e.g., the flapper  151 ) is configured to extend generally vertically when in the closed position. The valve  105  may be configured to move from the closed position to the open position during the flush cycle to affect the siphon, such that the valve  105  covers (e.g., to seal) the second opening  149  in the passageway  104  in the open position and exposes (e.g., to allow fluid communication) the second opening  149  in the closed position. 
     According to other examples, the valve  105  may be located in the down leg of the outlet leg  145 , such as the first portion  145   a . The location of the valve  105  may be tailored to the volume of water used to pre-prime the passageway  104 . For example, for long passageways having larger volumes, the valve  105  may be moved farther away from the outlet (e.g., at the second end  142 ) and closer to the dam  143 , such as to retain a predetermined total flush volume (e.g., 1.25 gallons). 
     According to an exemplary embodiment, the valve is moved (e.g., rotated, pivoted, actuated, etc.) between open and closed positions using an electromagnet. As shown in  FIG. 2 , the electromagnet  155  is located below a bottom of the passageway  104  (where the flapper  151 ′ is located in the closed position). The electromagnet imparts a magnetic force that rotates the valve  105  between the open and closed positions. The magnetic force may be applied to the pivot  152  and/or the flapper  151 . The electric power for controlling the electromagnet may be supplied by a power supply that is internal (e.g., within the toilet  101 ) or external, such as from the electric grid. According to an exemplary embodiment, the electric power is provided by an internal battery (e.g., 9V) that is removable and replaceable. According to another example, the electromagnet may be located at the pivot  152  to rotate the flapper  151  through the pivot  152 . 
     The toilet  101  may include a manual control for operating the valve  105 , such as in the event of power failure. As shown in  FIG. 2 , a knob  154  is provided to allow the valve  105  to be opened and closed when the knob  154  is rotated. The knob  154  can be configured to rotate the valve  105  directly or indirectly, such as through a gear train (e.g., a gear reduction, etc.). 
     Other devices may be used to move the valve, such as, for example, solenoids, motors (e.g., an electric motor), and other devices suitable to move the valve. The valve  105  may be controlled by any suitable device or in any suitable manner. For example, the valve  105  may be controlled by fluid (e.g., hydraulic, water, etc.) pressure, such as by a hydraulic piston that is driven by the water used with the toilet, or pneumatic (e.g., air) pressure. Water from the water supply to the toilet may open and close the valve  105 . Using the existing water pressure to control the valve may advantageously eliminate the need to use electric power and incorporate devices that use electric power in the toilet. These toilets can be used without external power sources. 
     The toilet  101  may include a release line  107  that is configured to release pressure (e.g., air pressure) from one portion of the system to another portion of the system. For example, the toilet  101  may include a release line  107  that vents to the drain pipe or the outlet of the passageway  104  that is fluidly connected with the drain pipe to act as a seal and/or keep gases from escaping. As shown in  FIG. 2 , the release line  107  extends between a first opening  148  in the passageway  104  and a second opening  149  in the passageway  104 . The release line  107  may release pressure from the portion of the passageway  104  proximate the first opening  148  to the portion of the passageway  104  proximate the second opening  149  and/or from the portion proximate the second opening  149  to the portion proximate the first opening  148 . The release line  107  may be a one-way line allowing pressure to be released in only one direction, or may be a two-way line allowing pressure to be released in two (e.g., opposite) directions. 
     The release line  107  includes a first end  171  and a second end  172 . The first end  171  is coupled to the passageway  104  such that the release line  107  is fluidly connected to the passageway  104  (e.g., at a first portion) through the first opening  148  and the first end  171 . The second end  172  is coupled to the passageway  104  such that the release line  107  is fluidly connected to the passageway  104  (e.g., at a second portion) through the second opening  149  and the second end  172 . 
     As shown, the first opening  148  in the passageway  104  is located upstream from the valve  105  and the second opening  149  in the passageway  104  is located downstream of the valve  105 . This arrangement may advantageously permit air pressure to be released when the valve  105  is closed and a volume of water is in the passageway  104  upstream from the valve  105 . As shown, the first opening  148  is located upstream from the inlet  147  in the passageway  104 . 
     The toilet  101  may include a check valve  175  located in line with the release line  107  to prevent water and waste from back flowing. For example, the check valve  175  may be located proximate the first opening  148  of the passageway  104  and/or the first end  171  to prevent water and waste from flowing into the release line  107  through the first opening  148  (and down toward the second opening  149  and/or the second end  172 ). The check valve  175  may allow air to flow, such as, for example, from the second opening  149  to the first opening  148  (and out into the passageway  104  through the first opening  148 ) while preventing water and waste (e.g., liquids, solids) from flowing from the first end  171  toward the second end  172 . 
     Although  FIG. 1  depicts a partially skirted toilet  101 , the concepts (e.g., pre-primed concepts) of the siphonic toilets disclosed in this application can be incorporated into any other type of toilet as well. For example, the concepts of the siphonic toilet disclosed herein can be incorporated into fully skirted toilets, wall-mount toilets, smart toilets, as well as any other toilet. 
       FIGS. 3 and 4  illustrate an exemplary embodiment of a smart toilet  201  that is configured as a pre-primed siphonic toilet. As shown in  FIG. 3 , the toilet  201  includes a structure having a base cover  221  and a lid  222  that is movable relative to the base cover  221 . The lid  222  can be moved between an open position, which provides access to a bowl  203  of the toilet  201  through a bowl opening  231  (e.g., inlet opening), and a closed position (as shown in  FIG. 3 ). The bowl  203  includes a sump  233 , which may be configured to hold a volume of water. 
     The toilet  201  also includes a passageway  204  that is fluidly connected to the bowl  203 . The passageway  204  transfers water and waste from the toilet  201  to an outlet. As shown in  FIG. 4 , the passageway  204  includes a first end  241 , which is fluidly connected to the bowl  203 , and a second end  242 , which may serve as the outlet of the toilet  201 . The passageway  204  includes an inlet leg  244  and an outlet leg  245 . Also shown, the inlet leg  244  includes a first portion (e.g., down leg) extending downwardly from the first end  241  to a second portion (e.g., an up leg). The second portion of the inlet leg  244  extends upwardly from a bottom  246  (e.g., trap) of the passageway  204  to a dam (e.g., weir, etc.). The outlet leg  245  extends downwardly from the dam to the outlet (e.g., at the second  242 ). 
     The toilet  201  also includes a valve  205  for providing a pre-priming of the toilet for flushing. For example, the valve  205  can be configured to retain a volume of water in the passageway  204  to pre-prime the toilet  201  prior to a flush cycle. The valve  205  is located between the dam and the outlet (e.g., at the second end  242 ). As shown in  FIG. 4 , the valve  205  is located proximate the outlet. 
     The valve  205  includes a gate  252  configured, such as a flat member (e.g., a flapper), to rotate between an open position and a closed position. The closed position of the gate  252  is shown in  FIG. 4  using the solid lines, and the open position of the gate  252  is shown in  FIG. 4  using the dashed lines. When in the closed position, the gate  252  retains a volume of water in the passageway  204 . In an embodiment, water is retained in only the outlet leg  245  (e.g., from the dam downstream to the valve  105 ) to pre-prime the toilet  201 . In another embodiment, water is retained in the inlet leg  244  and the outlet leg  245  (e.g., when the toilet  201  includes a second valve, as discussed below in more detail). 
     The toilet  201  may include one or more than one flow controller. As shown in  FIG. 4 , a flow controller  206  is housed in the toilet  201  (e.g., within the base cover  221 ) to control water flow from an inlet fluid conduit  261  to an outlet fluid conduit  262 . The inlet conduit  261  introduces water into the flow controller  206  from a water source (e.g., supply, etc.). The source can be internal (e.g., tank) or external (e.g., water line) to the toilet  201 . The outlet conduit  262  introduces water into the outlet leg  245  through the inlet  247  (e.g., opening, entrance, etc.). The flow controller  206  meters (e.g., controls the amount of, to supply in a measured or regulated amount, etc.) the water introduced into the outlet leg  245  as well as the timing of when the water is introduced (e.g., pre-priming). Also shown in  FIG. 4 , a flow controller  209  is located in the base cover  221  and meters water into the bowl  203  from the water source. 
     The toilet  201  may include a release line. As shown in  FIG. 4 , a release line  207  extends between a first opening (e.g., upper opening above the dam) and a second opening (e.g., lower opening proximate the valve  105 ). The release line  207  may release air pressure, as described above for the toilet  101  (e.g., the release line  107 ). The toilet  201  may include a check valve  263 ,  275 , as described above for the toilet  101  (e.g., the check valve  175 ). 
     The toilet  201  may also include another valve. For example, the toilet  201  may include a second valve  208  to maintain a volume of water in the sump  233  of the bowl  203  (e.g., illustrated by the fill line  235  shown in  FIG. 4  using dashed lines) when the second valve  208  is closed. The second valve  208  may be configured to open, such as during a flush cycle, to allow water and waste to flow from the sump  233  into the passageway  204 . The second valve  208  may include a rotatable member (e.g., door, flapper, etc.) that rotates about a pivot (e.g., pivot axis, axis of rotation, etc.) between the open and closed positions. The second valve  208  may be advantageous for applications, for example, aimed at reducing water usage by utilizing the pre-prime volume of water in the passageway and the volume of water in the sump to generate a siphon during a flush cycle. The volume of water in the passageway may be reduced (e.g., filling only the outlet leg  245 ) when retaining the volume of water in the sump by the second valve  208 . It is noted that the second valve  208  is optional. 
       FIGS. 5-12  illustrate various exemplary embodiments of passageways (e.g., traps, trapways, etc.) that are configured for use in the toilets disclosed in this application (e.g., the toilets  101 ,  201 ). The passageways may be tubular to fluidly connect a bowl to a drain pipe to transfer water and waste from the bowl to the drain pipe. The passageways may include inlets (e.g., pre-prime inlets) that are configured to introduce water into the passageway to pre-prime the passageway. Valves (e.g., pre-prime valves) may be disposed in the passageways to hold water in the passageway to pre-prime the toilet.  FIGS. 5-9  illustrate the passageways alone (i.e., without other elements/features of the toilet), whereas  FIGS. 10-12  illustrate the passageways with other elements/features of the toilets. 
       FIG. 5  shows a passageway  304  extending from an inlet end  340  to an outlet end  341 . The inlet end  340  includes an inlet opening that is generally horizontally aligned. The inlet end  340  opens into (e.g., is fluidly connected with) a down leg  342 , which, as shown, extends downwardly. The down leg  342  opens into a cross leg  343 , which, as shown, extends horizontally to the outlet end  341 . The outlet end  341  includes an outlet that is generally vertically aligned. Disposed in the passageway  304  is a pre-prime inlet  347  that is configured to introduce water into the passageway  304  to pre-prime the passageway  304 . As shown in  FIG. 5 , the pre-prime inlet  347  is disposed upstream from the down leg  342  and downstream from the inlet end  340 . It is noted that the pre-prime inlet  347  can be located elsewhere in the passageway  304 . 
       FIG. 6  shows a passageway  404  extending from an inlet end  440  to an outlet end  441 . The passageway  404  has a generally S-shape. As shown, the passageway  404  includes a semi-circular portion  442  having the inlet opening, a generally straight portion  443  extending from the circular portion  442 , and an outlet portion  444  extending from the generally straight portion  443 . The outlet portion  444  may be semi-circular or may just turn downwardly to an outlet. As shown, the generally straight portion  443  has a cross sectional shape (e.g., size, area, etc.) that changes along its length. For example, the size of the generally straight portion  443  is relatively smaller at the ends proximate to the semi-circular portion  442  and the outlet portion  444 , while the size is relatively larger in the middle section. As shown in  FIG. 6 , a pre-prime inlet  447  is disposed in the passageway  404  at a location that is upstream from the generally straight portion  443  and downstream from the inlet end  440 . It is noted that the pre-prime inlet  447  can be located elsewhere in the passageway  404 . 
       FIG. 7  shows another generally S-shaped passageway  504  that extends from an inlet opening  540  to an outlet  541 . The passageway  504  includes a generally straight portion  543  provided between a semi-circular portion and an outlet portion. The generally straight portion  543  has a size that gradually increases moving from the end adjacent the semi-circular portion to the end adjacent the outlet portion. As shown in  FIG. 7 , a pre-prime inlet  547  is disposed in the passageway  504  at a location that is upstream from the generally straight portion  543  and downstream from the inlet  540 . It is noted that the pre-prime inlet  547  can be located elsewhere in the passageway  504 . 
       FIG. 8  shows a passageway  604  having an inlet portion  640  extending between an inlet opening  641  and a dam  642 . The passageway  604  also has an outlet portion  643  extending from the dam  642  to an outlet  644 . The outlet portion  643  has a down leg  645  extending from the dam  642  to a cross leg  646 . As shown, the down leg  645  extends generally vertically downward, and the cross leg  646  extends generally horizontal. A bulge  647  is provided in the down leg  645  creating a non-linear shape. As shown, the bulge  647  has a small indentation (shown at the left side in  FIG. 8 ) that has a generally V-shape. The side of the bulge  647  opposite the indentation is semi-circular or arcuate. The passageway  604  includes a pre-prime inlet  649 , such as at a location that is upstream from the bulge  647  and downstream from the inlet portion  640 . It is noted that the pre-prime inlet  649  can be located elsewhere in the passageway  604 , such as downstream of the bulge  647 . 
       FIG. 9  shows a passageway  654  having an inlet portion  660  with an inlet opening  661 . The inlet portion  660  includes a semi-circular portion and an up leg that extends from the semi-circular portion to a dam  662 . The passageway  654  includes an outlet portion  663  extending from the dam  662  to an outlet  664 . The outlet portion  663  includes two more semi-circular portions that form a generally S-shape with the dam  662 . As shown, the passageway  654  also includes a flange  665  extending around the outlet  664 . The flange  665  has a generally larger size (e.g., diameter) compared to the size of the outlet portion  663 . The size of the flange  665  may be tailored to the size of a drain pipe (not shown in  FIG. 9 ) for coupling the passageway  654  to the drain pipe. The passageway  654  includes a pre-prime inlet  667 , such as at a location that is upstream from the outlet portion  663  and downstream from the dam  662 . It is noted that the pre-prime inlet  667  can be located elsewhere in the passageway  654 . 
       FIG. 10  shows a tubular passageway  704  having an inlet portion  740  with an inlet opening  741  fluidly connected to a toilet bowl  703 . The inlet portion  740  includes a semi-circular portion and an up leg that extends from the semi-circular portion to a dam  742 . The passageway  704  includes an outlet portion  743  extending from the dam  742  to an outlet  744 . The outlet portion  743  includes a down leg and a cross leg extending from the down leg to the outlet  744 . Disposed in the outlet portion  743  (e.g., in the down leg and/or cross leg) is at least one rib that extends inwardly from the side wall of the tubular passageway  704 . As shown, the rib  745  has spiral shape (e.g., helical or a helix shape) moving from the top of the down leg adjacent the dam  742  down toward, into, or through the cross leg. The rib  745  may be located between the dam  742  and a valve for retaining a volume of pre-priming water. The rib  745  may slow the exit (e.g., rate) of pre-primed water. This arrangement may advantageously influence (e.g., extend) the timing to complete the siphon, which may remove more waste through a longer siphon. Thus, the timing of the siphon can be influenced by the system, such as the shape (e.g., geometric configuration) of the passageway. The passageway  704  includes a pre-prime inlet  747 , such as at a location that is upstream from the rib(s)  745  and downstream from the dam  742 . It is noted that the pre-prime inlet  747  can be located elsewhere in the passageway  704 , such as downstream from one or more rib(s)  745 . 
       FIG. 11  shows a passageway  804  fluidly connecting a toilet bowl  803  and a drain pipe  808 . The passageway  804  includes an inlet portion  840  located upstream of a dam  842  and an outlet portion  843  located downstream from the dam  842 . The inlet portion  840  includes an up leg extending from an outlet of the bowl  803  to the dam  842 . The outlet portion  843  includes an upper portion  844  extending from the dam  842  to a lower portion  845 , which is configured having a larger cross sectional size (e.g., diameter) compared to a size of the upper portion. The size of the lower portion  845  may be tailored to hold a predetermined volume of water. As shown, the lower portion  845  includes a first (e.g., cylindrical) portion disposed at the top and a second (e.g., tapered, frusto-conical) portion extending from the first portion to the drain pipe  808 . Disposed in the passageway  804  is a pre-prime inlet  847  that is configured to introduce water into the passageway  804  to pre-prime the passageway  804 . As shown in  FIG. 11 , the pre-prime inlet  847  is disposed in the upper portion  844  of the outlet portion  843  upstream from the lower portion  845  of the outlet portion  843  and downstream from the inlet portion  840 . It is noted that the pre-prime inlet  847  can be located elsewhere in the passageway  804 , such as depending on the water level in the passageway  804 . For example, the pre-prime inlet  847  may be provided above the water level, so for the water level WL&#39;, the pre-prime inlet  847  may be located anywhere above the water level WL&#39;. A valve  805  may be located in the lower portion of the outlet portion  843 . As shown in  FIG. 11 , the valve  805  is located at the bottom base of the lower portion of the outlet portion  843  where the lower portion meets the drain pipe  808 . The valve  805  includes a valve door  850  (e.g., flapper) that is moveable between a closed position and an open position. For example, the valve door  850  may rotate about a pivot  851  between the open and closed positions. In the closed position, the valve door  850  seals the exit of the passageway  804  from the drain pipe  808  to prevent the transfer of water and waste from the passageway  804  to the drain pipe  808 . The valve door  580  is configured to retain a volume of water in the closed position to pre-prime the toilet prior to the next flush cycle. In the open position, the valve door  850  allows water and waste to pass from the passageway  804  into the drain pipe  808 . The water level WL can be changed to influence the siphon during the flush cycle, such as to the alternate levels shown using WL&#39; and WL″ in  FIG. 11 . 
       FIG. 12  shows a passageway  904  fluidly connecting a toilet bowl  903  and a drain pipe  908 . The passageway  904  has a shape that is substantially similar to the shape of the passageway  104  shown in  FIG. 2 , except where noted otherwise. The water level can be tailored to affect the performance of the flush cycle. As non-limiting examples, the water level can be at the height indicated by WL, WL′, or WL″ as shown in  FIG. 12 . A valve may be disposed in the passageway  904  to retain a volume of water therein to pre-prime the flush cycle of the toilet having the passageway  904 . The valve may be located anywhere within the cross-hatching  910  shown in  FIG. 12 , including at the outlet of the passageway  904  or in the drain pipe  908 . For example, the valve may be integrated with a floor flange configured to secure the passageway  904  and the drain pipe  908 . Disposed in the passageway  904  is a pre-prime inlet  947  that is configured to introduce water into the passageway  904  to pre-prime the passageway  904 . As shown in  FIG. 12 , the pre-prime inlet  947  is disposed above the water level WL″ and downstream from an inlet portion  940 . It is noted that the pre-prime inlet  947  can be located elsewhere in the passageway  904 , such as depending on the water level in the passageway  904 . For example, the inlet may be located at the location shown for the inlet  947 ′, such as for an embodiment configured to fill water in the passageway  904  to the water level WL. 
     A valve, such as the valve  105 ,  205 ,  208 ,  805 , can be located anywhere in the passageways shown in  FIGS. 5-12 . Furthermore, more than one valve can be used with each of the passageways shown in  FIGS. 5-12 . 
     An exemplary method of flushing a toilet, such as the toilets  101 ,  201 , will now be described. The method includes (e.g., as a first step) filling and retaining a first volume of water in a bowl and/or an up leg of a passageway that is downstream from the bowl and upstream from a dam. The first volume of water may be retained in the toilet by the geometry (e.g., configuration, shape, etc.) of the bowl, the passageway, a valve (e.g., the second valve  208 ), another element/feature, or any combination thereof. 
     The method includes (e.g., as a second step) filling and retaining a second volume of water in the passageway between a valve and the dam. For example, the valve may retain the second volume of water in the passageway when in a closed position. The second volume of water may be introduced into the passageway using a flow control device, which may be configured to meter out a specific amount of water. According to an embodiment, the second volume of water is introduced into the passageway prior to the activating the flush cycle through an inlet in the passageway (e.g., a pre-prime inlet), which is located downstream of the dam and upstream from the valve. 
     The method includes (e.g., as a third step) activating a flush cycle of the toilet. The activation of the flush cycle may be configured to introduce a third volume of water into the bowl, such as through a rim channel, jet, other suitable element/feature, or combination thereof. The activation of the flush cycle moves the valve retaining the pre-prime volume of water from the closed position to an open position to affect a siphon during the flush cycle. If the toilet includes more than one valve, such as the second valve  208 , then the second valve can be moved to an open position upon activation of the flush cycle. The order between the opening of the valves (for toilets having more than one valve) may be tailored, such as to affect the siphon. 
     The method may also include venting (e.g., releasing) air through a release line (e.g., an air pressure release line). The release line may extend between a first opening in the passageway, which is upstream from the inlet and/or downstream of the dam, and a second opening in the passageway, which is downstream of the valve. Further, when the valve is in the open position the valve may be configured to seal off the second opening in the passageway to prevent the flow of water and waste into the air pressure release line. 
     The method may also include closing the valve (or valves if more than one valve is used during the flush cycle). The valve may be closed after evacuation of the water and waste. If the toilet includes more than one valve, the order in closing the valves may be tailored. 
     The method may also include introducing water into the system to pre-prime the toilet for a subsequent flush cycle. For example, the valve in the passageway for pre-priming may be closed after evacuation of the water and waste, then water may be introduced into the passageway (e.g., through the inlet) to pre-prime the toilet. 
     The pre-primed siphonic toilet, as disclosed herein, provide multiple advantages/benefits, some of which are described above. Another such advantage is that the toilets can operate without a tank (i.e., the toilets of this this application can be configured as “tankless” toilets) thereby reducing size and cost (e.g., material, labor, packaging, etc.) and allowing for more freedom of design regarding the toilets. The system (e.g., the flushing engine) is a “line pressure system” since it can be configured to operate based on line pressure, as opposed to “gravity flushing systems” that rely on gravity to operate. In addition to utilizing line pressure for flushing, the systems disclosed herein may also utilize line pressure for other functions, such as those that would otherwise require electronics and a power source. 
     As discussed above, the toilets of this application enable the use of grey-water in the flushing system without degrading performance or exposing the customer to “grey” or possibly contaminated water. From a user&#39;s perspective, the toilets appear as conventional toilets utilizing only fresh water, but use far less fresh water when using grey water, such as for the pre-priming. Thus, the grey-water toilets appear and function at least as well as a standard line fed toilet. The grey water toilets of this application can be configured both with and without a conventional tank. 
     Also, the toilets of this application are configured to reduce the total volume of water used for each flush cycle of solid and/or liquid waste. This is in addition to being able to drastically reduce the volume of fresh water used for each flush cycle, such as by using grey water for pre-priming the passageway. 
     Also, the toilets of this application are able to reduce the time (e.g., actual time in seconds) it takes to complete each flush cycle. For example, the pre-priming eliminates the amount of time that conventional toilets take to prime after activation of the flush cycle. Thus, by pre-priming the passageway of the toilet, the priming phase of the flush is eliminated or reduced to a fraction of the time required in a traditional toilet design. 
     The pre-primed traps/trapways/passageways of this application function differently than toilets that, for example, use existing line pressure for flushing. For example, the pressurized water from the supply does not have to be used directly to push the waste from the bowl. Instead, the pressurized water may be used to control secondary functions of the toilet/system, which can be designed to function on as little as approx. 1-5 psi and less than 1 gpm of flow. Line pressure toilets may require the jet in the sump to move/push the solid waste upward into the trapway, while also providing a high enough flow rate of water to prime the trapway (i.e., introduce the water into the trapway during the flush cycle) and create a siphon to evacuate the bowl. At low pressure and flow rate (e.g., approximately less than 35 psi and 2 gpm) these systems typically begin to perform poorly and will fail to perform at rates much higher than 5 psi and 1 gpm. A common line pressure toilet may fail to remove solid waste at 20 psi and 3 gpm. 
     For the toilets having pre-primed traps/trapways/passageways, the trapway is sealed off, such as, for example, at the outlet using a valve that can be opened and closed when desired. The features/elements of the valve (e.g., openings, etc.) are large enough to not obstruct the flow of waste and water from the system when opened. The trapway can be filled with water to a predetermined level while the valve is closed. While at rest (e.g., between flush cycles) the trapway remains filled with water (e.g., pre-primed). Pressure and flow rate supplied (e.g., fluctuations thereof) do not affect waste removal performance of the toilets/systems of this application. Low pressure and flow supplied to toilets/systems of this application may increase the amount of time required to fill the trapway (e.g., the time to pre-prime the trap) between flushes, but would not detrimentally impact performance (e.g., waste/water removed with each flush). This is advantageous, because the toilets of this application will not fail to flush or fail to siphon at low pressure/flow. 
     The major components of the toilets of this application may be configured to operate or control operation of the primary and secondary functions, which can be designed in any number of different embodiments, such as any toilet disclosed herein. In an embodiment, the secondary functions that control the opening and closing of the valve in the passageway (e.g., the valve  105 ), timing of rim wash, and actuating the flush can all be controlled with water pressure. Accordingly, the entire system may be designed to function without electrical components. 
     In another embodiment, one or more than one electronic components may be used to control some or all of the toilets/systems functions. By way of example, an electric motor can be used to open and close the valve in the passageway (e.g., the valve  105 ). Solenoids and a simple circuit with programming can be used to control rim wash, bowl and trap refill, and/or operating a hydraulic piston to open and close the trap valve. Electromagnetic field or other proximity sensors can be used to achieve desired functions, and timing said functions. It is noted that various combinations of electronic and hydraulic functions may be utilized with the toilets of this application. 
     As utilized herein, the terms “approximately,” “about,” “substantially”, and similar terms are intended to have a broad meaning in harmony with the common and accepted usage by those of ordinary skill in the art to which the subject matter of this disclosure pertains. It should be understood by those of skill in the art who review this disclosure that these terms are intended to allow a description of certain features described and claimed without restricting the scope of these features to the precise numerical ranges provided. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations of the subject matter described and claimed are considered to be within the scope of the invention as recited in the appended claims. 
     The terms “coupled,” “connected,” and the like, as used herein, mean the joining of two members directly or indirectly to one another. Such joining may be stationary (e.g., permanent) or moveable (e.g., removable or releasable). Such joining may be achieved with the two members or the two members and any additional intermediate members being integrally formed as a single unitary body with one another or with the two members or the two members and any additional intermediate members being attached to one another. 
     References herein to the positions of elements (e.g., “top,” “bottom,” “above,” “below,” etc.) are merely used to describe the orientation of various elements in the FIGURES. It should be noted that the orientation of various elements may differ according to other exemplary embodiments, and that such variations are intended to be encompassed by the present disclosure. 
     The construction and arrangement of the elements of the siphonic toilets as shown in the exemplary embodiments are illustrative only. Although only a few embodiments of the present disclosure have been described in detail, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter recited. For example, elements shown as integrally formed may be constructed of multiple parts or elements, the position of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be altered or varied. 
     Additionally, the word “exemplary” is used to mean serving as an example, instance, or illustration. Any embodiment or design described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments or designs (and such term is not intended to connote that such embodiments are necessarily extraordinary or superlative examples). Rather, use of the word “exemplary” is intended to present concepts in a concrete manner. Accordingly, all such modifications are intended to be included within the scope of the present disclosure. Other substitutions, modifications, changes, and omissions may be made in the design, operating conditions, and arrangement of the preferred and other exemplary embodiments without departing from the scope of the appended claims. 
     Other substitutions, modifications, changes and omissions may also be made in the design, operating conditions and arrangement of the various exemplary embodiments without departing from the scope of the present invention. For example, any element (e.g., passageway, leg, valve, flow control, air pressure release line, pre-prime inlet, electromagnet, etc.) disclosed in one embodiment may be incorporated or utilized with any other embodiment disclosed herein. Also, for example, the order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. Any means-plus-function clause is intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures. Other substitutions, modifications, changes and omissions may be made in the design, operating configuration, and arrangement of the preferred and other exemplary embodiments without departing from the scope of the appended claims.