You are an expert at summarizing long articles. Proceed to summarize the following text:

You are an expert at summarizing long articles. Proceed to summarize the following text: 
CROSS REFERENCE TO CO-PENDING APPLICATION 
   This application is a continuation of U.S. patent application Ser. No. 09/982,424, filed Oct. 18, 2001 in the name of Karl Blankenburg and entitled “VACUUM ASSIST TOILET”, abandoned, the contents of which are incorporated herein in its entirety. 

   BACKGROUND 
   This invention relates to a vacuum assisted toilet that uses less water than a conventional toilet. Specifically, the invention refers to a method and apparatus for creating a vacuum downstream of the toilet and upstream of a discharge pipe leading to a sewer pipe or a waste holding tank. 
   Reducing the amount of water used for each flush has long been a goal of designers of waste removal, or toilet systems. Pursuing this goal has been attempted predominantly in two ways. First, designers have implemented pressurized water holding tanks above the toilet so that water at elevated pressure levels enters the bowl during the flush cycle. Second, designers have applied a vacuum force downstream from the toilet. This second approach, in turn, can be divided generally into two categories. The first category is demonstrated by airplane toilet systems. In these devices a vacuum is applied downstream from a holding or receiving tank. Thus, the vacuum force is applied both to the receiving tank, the discharge trapway and the toilet. The second category of vacuum assisted toilets in the art is a vacuum situated along the discharge trapway that ramps up in intensity as the flushed water evacuates the bowl. 
   The shortcoming of each of these types of vacuum assisted toilets is that the evacuator force of the vacuum is used inefficiently. The less water used during a flush, the more efficient a toilet is. In the airplane toilet systems, the evacuator force is not applied in the discharge trapway alone. Rather, the vacuum is applied to a holding tank as well. It is in the discharge trapway where the vacuum is most needed. When the evacuator force has been applied along the discharge trapway, it has been inefficient in that the force increases in intensity only when the leading edge of the flushed water has passed. As a result, the highest levels of evacuator force produced by the prior known devices is directed to the flushed water in a direction away from the holding or receiving tank. 
   It would be desirable to provide a toilet system where vacuum is created between the toilet and the discharge piping or a receiving tank, such that the vacuum acts to draw the flushed water from the toilet, through the discharge piping, and to the receiving tank. Further it would be desirable to apply this evacuator force at a location along the discharge passage so that the maximum amount of force is applied to draw the contents of the toilet bowl out of the toilet bowl and into the discharge piping. 
   SUMMARY OF THE INVENTION 
   The present invention provides a highly efficient vacuum assisted toilet. The invention is a toilet having a bowl capable of containing a waste liquid, a flushing actuator to initiate flushing of the toilet bowl, and a discharge port. A discharge passage is fluidically connectable to the discharge port of the toilet and to a waste outlet. A source of vacuum is fluidically connectable to the discharge passage in response to activation of the flushing actuator to withdraw the waste liquid from the toilet bowl under pressure through the discharge passage to the waste outlet. 
   The toilet can also include a vacuum application valve, a vacuum reservoir and an air compressor or pump. The reservoir can be connected to the valve at one end and, at the other end, to an inlet of an air compressor or pump. In addition to being connected to the reservoir, the valve is connectable to the discharge passage. The air compressor or pump draws gas out of the vacuum reservoir while the valve is closed, thus creating a vacuum in the reservoir. 
   The toilet of the present invention also includes a flap valve which is located downstream in the discharge passage. The flap valve is positioned at a location in between the vacuum valve and the waste outlet. The flap valve is essentially a one way valve preventing gas or liquid from flowing upstream to the toilet and creating a smaller downstream chamber. 
   When the toilet is flushed by activation of the flushing actuator, the valve opens drawing gas and/or air within the discharge passage into the reservoir. As a result, vacuum is created in the discharge passage. The opening of the valve is coordinated with the activation of the flushing mechanism of the toilet. Once vacuum has been created in the discharge passage for a predetermined time, the valve shuts such that none of the waste liquid in the toilet bowl enters the valve or the reservoir. 
   The vacuum assisted toilet of the present invention can also include a vacuum level switch. The vacuum level switch is positioned on the vacuum reservoir and permits the level of vacuum within the reservoir to be modified. Modifying the degree of vacuum within the reservoir can be used to modify the characteristics of the flushing operation. 
   The vacuum assisted toilet of the present invention can also include a control module for controlling the operation of the toilet components. The control module, for example, can control the opening and closing of the vacuum application valve, the function of the pump and, optionally, the operation of the flap valve. The addition of the control module can further enhance the efficiency of the flushing operation. 
   The present invention also teaches a method for providing vacuum pressure to assist in the flushing of a toilet. A flushable toilet system is provided. The system can include a toilet and a passage leading to a waste discharge outlet. A source of vacuum is provided and fluidly connected to the discharge passage. The vacuum source can be closed from communication with the discharge trap so that waste liquid from the toilet will not enter the vacuum source. When the toilet is flushed, the vacuum source is placed in communication with the discharge passage for a desired length of time. The vacuum source can be closed before the waste liquid from the toilet reaches the vacuum source. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The various features, advantages and other uses of the present invention will become more apparent by referring to the following detailed description and drawing in which: 
       FIG. 1  is a schematic diagram of a vacuum assisted toilet according to the present invention; 
       FIG. 2  is a block diagram of the control for the present vacuum assisted toilet; and 
       FIG. 3  is a schematic diagram of circuitry for controlling the operation of the present invention. 
   

   DETAILED DESCRIPTION 
   Referring to  FIG. 1 , a vacuum assisted toilet  10  of the present invention is depicted. The toilet  10  according to the present invention includes a bowl  12 , a discharge port  14  and a flushing actuator  16 . The bowl  12  of the toilet  10  is capable of containing a waste water or liquid stream  18 . During a flush cycle, the waste stream  18  in the bowl  12  is evacuated through the discharge port  14 . The discharge port  14  is fluidly connected to a discharge passage  20 . In addition, in a preferred aspect, the discharge passage  20  is a pipe with multiple openings  22  and  24 , which joins the toilet  10  to a waste outlet through a discharge pipe  28 . Generally, the discharge pipe  28  can be connected at a waste outlet or opening  26  to a holding device  30 , by way of example and not limitation, such as a holding tank or septic tank. Alternatively, the discharge pipe  28  can be connected at opening  26  to a sewer line. The discharge passage  20  can include a trap that is essentially a local valley in the discharge passage  20  that will collect water and the like for preventing gas and liquid from evacuating from the discharge pipe  28  while allowing the waste water stream  18  to travel along the discharge pipe  28 . 
   The discharge passage  20  extends a predetermined length from the toilet  10  to the discharge pipe  28 . A vacuum source  32  is attached to the discharge passage  20  at some point between the toilet  10  and the discharge pipe  28 , preferably at a point above the center line of the discharge passage  20 . The vacuum source  32  is fluidly connected to the discharge passage  20 . The vacuum source  32  can include a valve  34  that is operable such that the waste water stream  18  from the toilet  10  will be prevented from flowing into the vacuum source  32 . 
   In one aspect of the invention, the vacuum source  32  can include the valve  34 , a vacuum reservoir  36  and a pump  38 . The valve  34  is fluidly connected to the discharge passage  20  and to the reservoir  36 . The opening and closing of the valve  34  is subject to the initiation of a flushing cycle in the toilet  10 . The valve  34  opens for a relatively brief period of time, when the flushing actuator  16  is used to initiate a flushing cycle. 
   The vacuum reservoir  36  is fluidly connected to the valve  34  and the pump  38 . The reservoir  36  is a relatively rigid container capable of sustaining a predetermined shape while storing a vacuum of desired strength. The pump  38  is attached to the reservoir  36  and draws fluid from the reservoir  36 . The pump  38 , by way of example and not limitation, can take the form of a blower, an air compressor or any similarly functioning apparatus now known or later developed in the art. 
   Although the reservoir  36  and the pump  38  may be mounted in any convenient location within a building or home, a preferred mounting location is between the wall studs in the bathroom or directly below the bathroom in a basement or crawlspace, if such is available. 
   In addition, although  FIG. 1  and the description of the toilet  10  describe the use of the reservoir  36  and pump  38  with a single toilet  10 , it will be understood that a single reservoir  36  and a single pump  38  may be employed with multiple toilets  10  in various locations throughout a home or building. In such a multi-toilet application, a separate valve  34  is provided for each separate toilet  10  and is mounted in the same manner as that described above and shown in  FIG. 1  in fluid communication with the discharge passage  20  and a conduit extending to the reservoir  36 . 
   The vacuum assisted toilet  10  includes a flap valve  40  positioned within the discharge passage  20  at a location between the port or outlet  24  to the valve  34  and the discharge pipe  28 . The flap valve  40  prevents upstream flow. As used herein, “upstream flow” refers to travel along the discharge passage  20  from the discharge pipe  28  to the toilet  10 . In an example, the flap valve  40  takes the form of a flap or one-way valve. The vacuum created by the vacuum source  32  draws waste water  18  out of the toilet  10 . The flap valve  40  is added to the discharge passage  20  prior to communication with the discharge pipe  28  to produce a greater vacuum in the discharge passage  20 . 
   The flap valve  40  is in a normally closed position closing the discharge passage  20  to flow of waste water stream  18  at the time of activation of the flushing actuator  16  and the application of the vacuum to the discharge passage  20 . 
   The toilet  10  can also include a switch  42 , as is shown in  FIG. 1 , for controlling the degree of vacuum within the vacuum reservoir  36 . As is well known, “vacuum” is a state of lower pressure. The lower the pressure, in comparison to the pressure of the ambient air, the greater the “degree of vacuum.” A vacuum level switch  42  may be added to the vacuum reservoir  36  in order to calibrate the degree of vacuum to an optimum level. The vacuum level switch  42  can be manual or automated. 
   The present invention can also include a control module  44  for controlling the function of the present toilet. As best shown in  FIG. 2 , in a preferred embodiment, the control module  44  controls the operation of the valve  34  to move to an open fluid flow state, when the flushing actuator  16  of the toilet  10  is activated. The control module  44  can optionally control the motion of the flap valve  40  positioned within the discharge passage  20 . The control module  44  can also control the operation of the vacuum pump  38  or air compressor for negative pressure, and the vacuum level switch  42 . 
   The control module  44  includes a power convert circuit  50 , shown in detail in  FIG. 3 . The power convert circuit  50  includes a transformer  52  which converts incoming A.C. line voltage to a stepped down A.C. voltage. A full wave bridge  54  is connected to the output of the transformer  52  to convert the stepped down A.C. voltage to a D.C. voltage suitable for use with the electronic components used in the control module  44 . A voltage regulator  56  is coupled to the output of the bridge  54  to maintain a regulated voltage for of the circuitry of the control module  44 . 
   The control module  44  also includes a control logic circuit in the form of a microprocessor  60  which executes a stored control program. The flush actuator switch  16  of the toilet  10  and the vacuum level switch  42  are input to the microprocessor  60 . Outputs from the microprocessor  60  are connected to the vacuum valve  34  and the motor/pump  38  attached to the reservoir  36 . An optional output is provided from the microprocessor  60  to the flap valve  40 . 
   Drivers or relays are connected between the outputs of the microprocessor  60  and the various output devices to provide isolation as well as to enable the necessary voltage, typically an A. C. voltage, to be provided to the motor/pump  38  or a low level D.C. voltage to the solenoid of the vacuum valve  34 . 
   Thus, as shown in  FIG. 3 , one output of the microprocessor  60  drives a light emitting diode  62  connected to a light responsive triac driver  64 . The triac driver  64  is coupled to an A.C. power line to provide A.C. power to the motor/pump  38 . 
   Another output of the microprocessor  60  is connected to the gate of a mosfet transistor  68  which connects D.C. power to the solenoid of the vacuum valve  34 . A similar mosfet switch or gate may be employed to control the solenoid of the optional flap valve  40 . 
   Microcontroller  60 , in addition to providing timing and control of the vacuum pump, valves, etc., as described above, also performs system error checking. These error checking functions include monitoring excessive pump running time and detection of vacuum leaks by pressure a pressure drop in the absence of a flush event. 
   In operation, the flushing actuator  16  of the toilet  10  containing a waste water stream  18  is actuated. At the same time, the vacuum valve  34  is opened, and the flap valve  40  remains shut. At this moment, a volume of air is defined by the leading edge  46  of the waste water stream  18 , the flap valve  40  and the interior surface of the discharge passage  20 . When the vacuum valve  34  opens, the vacuum within the reservoir  36  draws the volume of air located in the discharge passage  20  into the reservoir  36 . The valve  34  is then closed, as the waste water  18  is quickly drawn through the discharge passage  20 . The length of time that the valve  34  is maintained in an open position is based on the particular system. For example, system variables can include the overall length of the discharge passage  20 , the length of the discharge passage  20  between the toilet  10  and the valve  34 , the desired degree of vacuum contained within the reservoir  36 , the volume of fluid disposed between the leading edge  46  of the waste water and the flap valve  40  within the discharge passage  28 , as well as any other pertinent factors. In establishing a period of time that the valve  34  is open, it is desirable to ensure that waste water stream  18  does not enter the valve  34  or the reservoir  36 . The waste water stream  18  will flow past the closed vacuum valve  34  and proceed through the flap valve  40  to the discharge pipe  28 . 
   The vacuum assisted toilet  10  of the present invention can also be practiced with a pressurized tank. Pressurized tanks are well known in the toilet art aid need not be described here. In the preferred embodiment of the current invention, a pressurized tank can be used so that the combination of pressurized tank and vacuum assisted flushing will provide the most efficient use of water in a flushing cycle. 
   The present invention also teaches a method for providing vacuum to assist in the flushing of a toilet described above. When the flushing actuator  16  is engaged, the control module  44  or microprocessor  60  activates the vacuum valve  34  to an open state. At this time, the flap valve  40 , remains in a closed position. At this moment, the volume of air in the discharge passage  20  is defined by the leading edge  46  of the waste water stream  18 , the flap valve  40 , and in the interior surface of the discharge passage  20 . When the vacuum valve  34  is opened, the vacuum within the reservoir  36  draws the volume of air in the discharge passage  20  into the reservoir  36 . The valve  34  is then closed by the control module  44  or processor  60  as the waste water stream  18  is quickly drawn through the discharge passage  20  passes the location of the valve  34 . The length of time that the valve  34  is maintained in an opened position is based on the particular system. 
   The waste water stream will then flow passed the closed vacuum valve  34  and proceed through the flap valve  40  which is moved to an open position to the discharge pipe  28 . 
   Thus, there has been described a unique vacuum assisted toilet and method of operating a toilet in which a vacuum is drawn in a discharge passage between a waste water stream held in a toilet bowl and a controllable valve in the discharge passage intermediate the waste water stream in the toilet bowl and a discharge pipe extending to a holding tank, septic tank or sewer or other waste outlet. The vacuum assisted toilet of the present invention is easily implemented in an existing building structure and can accommodate one or multiple toilets in a single system with only a single vacuum source and vacuum reservoir. The vacuum assisted toilet of the present invention is extremely efficient insofar as the fact that the vacuum is applied to only a minimal amount of air so as to be able to quickly remove the air from the discharge passage for a quick evacuation of the waste liquid stream from the toilet bowl under the influence of a high vacuum pressure.

Summary:
A toilet is provided with a vacuum to assist in the flushing process. The vacuum is provided downstream between the toilet bowl and a waste outlet to draw the waste contents of the toilet bowl and out of the toilet bowl to the waste outlet under pressure. A controllable valve connected to a vacuum source is connected in a discharge passage between the toilet bowl and the waste outlet. The valve is opened to apply vacuum to the discharge passage upon activation of a toilet flush actuator and closes prior to the waste contents of the toilet bowl reaching the location of the valve. A normally closed flap valve is connected between the discharge passage and the waste outlet to define a minimal amount of air in the discharge passage which is removed by the vacuum.