Abstract:
A low volume high-pressure toilet. When the user sits on the toilet seat, a hydraulic piston pressurizes the water tank, which optimally holds 1.7 liters of water. Water is released at high pressure through the toilet interior rim and a lower waterjet, forcing the wastewater down a waste pipe. To minimize velocity pressures losses that would be caused by a p-trap, the waste is released straight down a pipe. Sewer gases are prevented from traveling back up the pipe by a sealing valve that occludes the cross sectional area of the waste cavity in the bottom of the toilet.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Not applicable. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     This invention relates to a low water toilet. Specifically, the invention describes a toilet using less than 2.0 liters of water, preferably 1.7 liters, at high pressure to flush waste. 
     2. Related Art 
     Prior art toilets in permanent structures have been in three types: gravity-tank, pressure-tank and tankless. Gravity tank toilets, the most common in the U.S., have a tank that holds between 6 and 15 liters of water. The water is released through holes in the rim of a toilet bowl and through a lower waterjet, creating a suction effect in a siphon tube that leads to a sewer line. The siphon tube is typically a “P-trap” shape that retains water in the bottom of the “P” loop to prevent sewer gas from backing up from the sewer line. Gravity tank toilets have the limitations of requiring high volumes of water per flush, followed by typically slow refill rates of the water tank. 
     Pressure-tank toilets are a modified gravity-tank toilet, wherein pressure of inlet water compresses air in an inner tank. This compressed air assists the flush process. However, like the standard gravity-tank toilet, a relatively high volume of water is required for each flush. 
     Tankless toilets are typically found in commercial locations. They require higher water pressure than gravity tank toilets, but still require a relatively high volume of water for each flush (typically 6 liters or more). 
     High pressure/low water volume toilets are also described in the prior art. These toilets rely on constriction nozzles that increase the dynamic pressure of the water passing through. These nozzles then direct their spray against the interior surface of the toilet bowl, spraying off the bowl and the waste contained therein. Such systems require an inlet water supply having higher hydrostatic pressure than found in most municipal systems to drive the water through the nozzles. 
     It would therefore be useful improvement of the prior art for a toilet to efficiently flush waste using a minimal amount of high-pressure water without relying on a remote source of high pressure. 
     BRIEF SUMMARY OF THE INVENTION 
     Accordingly, the objectives of this invention are to provide, inter alia, a new and improved low water toilet that: 
     uses less than 2.0 liters of water per flush; 
     is capable of creating its own high hydraulic pressure; 
     does not allow sewer gases to back up; and 
     is cost efficient. 
     These objectives are addressed by the structure of the inventive toilet. A hydraulic piston pressurizes a water pressure tank. The hydraulic piston is positioned beneath the toilet seat, so that it is depressed when the person sits on the seat. Approximately 300 ml of water are initially in the bowl of the toilet, positioned above a waste tube. A sealing valve retains water and waste in the waste tube. A working lever is pushed to initiate the toilet flushing cycle. When the toilet is flushed, the sealing valve is cycled downward to allow the wastewater to flow out a waste pipe, and simultaneously high-pressure water is released from the water pressure tank though a waterjet in the lower portion of the toilet bowl and from interior rim of the toilet. As the flushing cycle continues, the sealing valve reseals the waste tube, and residual pressure from the water pressure tank fills the tank with the starting level (approximately 300 ml) of water. 
     To minimize velocity pressures losses that would be caused by a p-trap, the waste is released straight down a pipe. Sewer gases are prevented from traveling back up the pipe by a sealing valve that occludes the cross sectional area of the waste cavity in the bottom of the toilet. 
     Other objects of the invention will become apparent from time to time throughout the specification hereinafter disclosed. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 depicts a partial cutaway side view of the inventive toilet. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention is described as toilet  10 , depicted in FIG.  1 . 
     Water storage tank  20  holds water used to flush toilet  10 . In the preferred embodiment, water storage tank  20  holds 1.5 to 2.0 liters, preferably 1.7 liters. Connected to water storage tank  20  is water inlet  30 . Water inlet  30  preferably includes check valve  31 , typically located at the interface of water inlet  30  and water storage tank  20 . 
     Water storage tank  20  is connected and in fluid communication, through pressure line  23  to the interior of piston  29  above hydraulic piston head  25  via hydraulic piston pressure outlet  26 . While piston  29  is understood to be a hydraulic piston, it is understood that alternative pressurization mechanisms, including but not limited to pneumatic pumps, may be used in the alternative to accomplish the below described function of piston  29 . Piston  29  includes hydraulic piston head  25 , piston rod  27  and piston return spring  28 . Exiting water storage tank  20  is pressurized water outlet  35 , which is connected and in fluid communication by hoses (not shown) to interior rim  57  and waterjet  80 . 
     Working lever  40  is preferably mechanically connected to gearing  70  (not shown), gearing  70  comprising a larger gear (not shown) and pinion gear  71 . Working lever  40  is laterally connected with the larger gear (not shown). The larger gear is engaged with pinion gear  71 , preferably in an increasing ratio such that angular rotation of the larger gear results in greater angular rotation of pinion gear  71 . Pinion gear  71  is laterally connected to lever  72 , which translates the rotational movement of pinion gear  71  to linear movement and attaches to linkage wire  63 . Linkage wire  63  loops around wire pulley  64  and connects to seal push rod  65 . Surrounding and axial to seal push rod  65  is push rod spring  67 . Seal push rod  65  is attached to sealing valve  60 , which is slidably inserted into and sealing against the inner walls of waste cavity  90 . Below waste cavity  90  is waste pipe  85 , which leads to a sewer line (not shown). 
     OPERATION 
     In the preferred embodiment shown in FIG. 1, toilet  10  works in the following sequence. Note that at the beginning of each flush sequence, a small amount of water, preferably 300 ml, is in the bottom of bowl  50  and in waste cavity  90 . 
     Water enters water storage tank  20  via water inlet  30 . Water inlet  30  is connected via a hose, preferably a high-pressure hose, to a water supply, such as a municipal water line. The incoming water pressure is typically in the range of 12-35 psi (82-240 kPa); thus the initial pressure in the water storage tank is initially at this same pressure. The water inlet  30  fills water storage tank  20 , which typically has a capacity of less than 2.0 liters, preferably 1.7 liters. 
     When solid waste is to be evacuated from toilet  10 , the following steps occur. The user sits on a toilet seat (not shown), typically attached to the toilet bowl exterior rim  55 , oriented above hydraulic piston head  25 . The toilet seat presses down on piston rod  27 , compressing piston return spring  28 . When hydraulic piston head  25  of piston  29  is in a depressed position, water from a line connected to hydraulic piston pressure outlet  26  is pulled into the cavity above piston  29 . When the user gets off the toilet seat, piston return spring  28  expands, returning piston  29  to its original position and forcing the water above piston  29  into the line connected to hydraulic piston pressure outlet  26 . Thus the water in the line leading from hydraulic piston pressure outlet  26  is now compressed to a high-pressure level proportional to the weight of the person who sat on the toilet seat. The hydraulic pressure in the line leading from hydraulic piston pressure outlet  26  is communicated through pressure line  23  to pressure inlet  24  into water storage tank  20 . Pressure line  23  is a high-pressure line, fabricated of metal or reinforced flexible material such as rubber. Alternatively, hydraulic pressure communication between piston  29  and tank  20  may be through a direct conduit or similar connection. The amount of pressure in the tank is adjustable in the preferred embodiment by a pressure regulator (not shown) associated with hydraulic piston head  25  and its related components. 
     To flush solid waste, the user depresses working lever  40 . Gearing  70  (not shown) increases the rotation of pinion gear  71  and its attached lever  72 . Linkage wire  63 , attached to lever  72 , loops around wire pulley  64 , and pulls sealing valve  60  by its seal push rod  65  to a second position. Water and waste located in the bottom of bowl  50  and waste cavity  90  are then released down waste pipe  85 . When working lever  40  is released, push rod spring  67  expands to return seal push rod  65  to its original first position, thus resealing waste cavity  90 . This seal prevents water from flowing down through waste pipe  85 , while at the same time preventing noxious and/or hazardous sewer gases from flowing upward from a sewer line (not shown) which is typically attached to waste pipe  85 . 
     Simultaneous with the movement of sealing valve  60  described above, depressing working lever  40  also releases pressurized water from water storage tank  20 . Depressing working lever  40  opens a high-pressure water valve (not shown) connected, typically via a first section of high-pressure hose, to pressurized water outlet  35 . The pressurized water is directed downstream through two second sections of hose, typically in parallel, leading away from the high-pressure water valve. One of the second sections of hose terminates under the toilet bowl interior rim  57 . The other second section of hose terminates at waterjet  80 . As the water pressure is released, a high velocity stream from interior rim  57  cleans the interior of bowl  50 , while simultaneously a second high velocity stream from waterjet  80  pushes out the wastewater from waste cavity  90  down into waste pipe  85 . When working lever  40  is released to its original position, water flowing through the high-pressure water valve is turned off. (Note that shortly after the initial release of high-pressure water, the main source of water pressure through the high-pressure hoses to interior rim  57  and waterjet  80  from water storage tank  20  is that provided by the inlet water supply.) When the high-pressure water valve is turned off, sealing valve  60  simultaneously reseals waste cavity  90 . Residual water on the sides of the interior of toilet bowl  50  then drains down into waste cavity  90 , providing a pool of approximately 300 ml of water. 
     When the user wishes to flush only liquid waste, high pressure is not required (although high pressure does not adversely affect flushing of liquid waste). If the user does not sit on the toilet seat, and thus water storage tank  20  is not pressurized by hydraulic piston head  25 , the system works on pressure provided by the water supply system, typically less than 35 psig. The operation of toilet  10  is the same as described above without the steps to pressurize water storage tank  20  (since the user does not sit on the toilet seat). 
     The foregoing disclosure and description of the invention is illustrative and explanatory thereof. Various changes in the details of the illustrated construction may be made within the scope of the appended claims without departing from the spirit of the invention. The present invention should only be limited by the following claims and their legal equivalents.