Patent Publication Number: US-6910231-B2

Title: Toilet system with a toilet pan

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The invention relates to a toilet system with a toilet pan, which can be flushed by a flushing arrangement, having a conduit which is connected to the toilet pan and leads to a waste-disposal conduit, having means for transporting a suction-extraction substance from the toilet pan into the conduit and into the waste-disposal conduit, the means having, in the conduit, two valves and, between the latter, a pressure chamber in which it is possible to produce a negative pressure, for the suction extraction of the substance from the toilet pan, and a positive pressure, for transporting the substance, once extracted by suction, into the waste-disposal conduit. 
   2. Description of the Related Art 
   Up until now, toilet systems in which the suction-extraction substance is extracted by means of a vacuum have been known, in particular, in vehicles, for example in railroad cars and RVs. For example, WO 92/18713 discloses a toilet system in which an arrangement for producing negative pressure has an intermediate tank and a collecting tank. The abovementioned arrangement evacuates the intermediate tank in order to produce negative pressure, with the result that, with a valve in a conduit being open, the substance is taken into the intermediate tank. Collecting tanks require a large amount of space and have to be emptied. They are not desirable for domestic use. 
   EP 0 887 478 discloses a toilet system in which a tank is likewise provided. A diaphragm pump is used to produce a partial vacuum in the tank, this resulting in a suction-extraction action. 
   EP 0 806 527 discloses a flushing arrangement which has a hollow, cup-like closure element. The closure element interacts with an inlet opening and an outlet opening, which are both open or closed in each case. 
   Toilet systems with a collecting tank in each case have additionally been disclosed by EP 0 704 372 and EP 1 022 399. 
   EP 0 763 633 A1 discloses a vacuum toilet which, in the discharge conduit, has a pressure chamber between two valves. By virtue of the negative pressure in this chamber, when a valve on the inlet side is opened, suction-extraction substance is sucked from the toilet pan, through the discharge conduit into this chamber. Once the two valves have been switched over, pressure forces the substance from the chamber into a further conduit. An ejector pump which is operated with compressed air is provided in order to evacuate the chamber. A folding bellows in the pressure chamber forms a flexible membrane and serves as a sealing means, and is intended to prevent foul air from passing outward out of the discharge conduit. The production of the negative pressure causes a spring to be stressed, the spring building up a pressure when relieved of stressing. The problem with this toilet system is that sealing the chamber by means of a flexible membrane involves high outlay and is fault-prone. In order to build up a negative pressure, an ejector pump requires a comparatively long period of time. In addition, the pressure which can be achieved in order to expel the substance from the chamber is very limited. This toilet system is not likely to prove successful in practice. 
   The object of the invention is to provide a toilet system of the abovementioned type which, with low water consumption, is functionally reliable and durable. 
   SUMMARY OF THE INVENTION 
   This object is achieved, in the case of a toilet system of the generic type, in that the pressure chamber is designed as a piston cylinder, and the piston is connected to a controllable drive in order to produce the positive pressure and negative pressure. In the case of the toilet system according to the invention, the negative pressure and positive pressure are produced by movement of the piston. This allows a very quick build-up of a negative pressure, for example within a fraction of a second. A positive pressure may likewise be produced very quickly and, in addition, with a positive pressure of more than 1 bar, for example approximately 2 bar. A further advantage of the toilet system according to the invention is that the displacement, and thus the volume of the substance which can be extracted by suction, can be adjusted precisely. It is also possible for two or more suction-extraction cycles to be carried out one after the other. A satisfactory flushing operation is thus possible with a very small amount of water. The piston of the piston cylinder here may itself serve as sealing means for preventing foul air from escaping outward. There is thus no need for a flexible membrane or the like. According to a development of the invention, the piston is moved by means of an electric motor. In conjunction with a control arrangement, this allows precise control of the suction-extraction and expelling operations. These operations, in addition, can be adjusted and adapted to the respective toilet pan. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic view of a toilet system according to the invention, 
       FIG. 2  is a further schematic view of a toilet system according to the invention, 
       FIG. 3  is a schematic view of the course of a flushing operation over time, and 
       FIGS. 4-6  are schematic views of a suction-extraction substance being taken in and expelled. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   According to  FIGS. 1 and 2 , the toilet system has a toilet pan  5  which is of hopper-like design and has a bottom outlet  5   a . This outlet  5   a , however, is comparatively small and has a cross section of, for example, 30 mm 2 . Connected to the underside of this outlet  5   a , in a conduit  29 , is a suction line  6 , which likewise has a comparatively small cross section. The toilet pan  5  can be flushed by a flushing arrangement  1 , and has a flushing pipe  3  through which flushing water can be directed into the interior of the toilet pan  5 . The flushing arrangement  1  may be a flushing cistern or some other suitable flushing arrangement. The essential factor, however, is that use is made of a comparatively small amount of flushing water, for example less than 1 liter. The flushing is triggered by a button  2  or by some other suitable triggering arrangement. Contactless or automatic triggering is also conceivable here. 
   The suction line  6  contains a valve  7  which, in a closed state, closes off the suction line  6  and, in the open state, releases the through-passage to a chamber  12  of a piston cylinder  8 . The valve  7  is controlled, via a signal line  24 , by a control arrangement  26 . 
   The piston cylinder  8  has a housing  9 , in which a piston  10  can be displaced to a limited extent in the directions of the double arrow  19 . The piston  10  subdivides the housing  9  into a bottom chamber  12  and into a top chamber  13 . The piston  10  seals these two chambers  12  and  13  in relation to one another. For this purpose, an encircling seal  10   a  is arranged on the outside of the piston  10 . The piston  10  is moved by a motor  14 , for example an electric motor, and is connected to the piston  10  via a piston rod  11  which, as can be seen, has one end projecting out of the housing  9 . During movement of the piston  10 , by means of valves  22  and  23 , air is expelled into the surroundings from the top chamber  13  and/or fresh air is drawn in from the ambient air. The valves  22  and  23  may be straightforward flap valves. Power is supplied to the motor  14  via a power line  15 . Power is likewise supplied to the control arrangement  26  via this line. The control arrangement  26  may also be integrated in the motor  14 . 
   The bottom chamber  12  has an outlet  12   a  which, as can be seen, is arranged at the lowermost point of the bottom chamber  12  and to which a pressure line  17  is connected. The pressure line  17  may be a flexible hose or a fixed pipeline. Located in the vicinity of the outlet  12   a  is a further valve  16 , which is controlled, via a signal line  25 , by the control arrangement  26 . In one state, the through-passage to the pressure line  17  is closed and, in the other state, this through-passage is free. The bottom chamber  12  forms a pressure chamber and this may be integrated in the toilet pan  5  and form a unit therewith. 
   The pressure line  17  has a cross section which may correspond essentially to the cross section of the suction line  6 . This cross section is thus likewise comparatively small and may be compared, for example, with that of a garden hose. It may be comparatively long, for example a number of meters in length, and, according to  FIG. 1 , lead to a downpipe of a waste-disposal conduit  18 . The pressure line  17  preferably has a front end  17   a  which projects comparatively deeply, for example a number of meters, into a waste-disposal conduit  18 . The pressure line  17  is introduced into the waste-disposal conduit  18 , for example, by way of a lateral connector  18   a.    
   The operation of the toilet system according to the invention is explained hereinbelow. 
   The rest state of the toilet system is shown in FIG.  2 . The valves  7  and  16  are closed and the piston  10  is located in the bottom position shown. When the toilet system is used, the flushing arrangement  1  may be actuated for preliminary wetting of the inside  5   b  of the toilet pan  5 . As a result of use, the suction-extraction substance  4  collects in the toilet pan  5 , the substance filling the suction line  6  as far as the valve  7 . Flushing is triggered by actuation of the button  2 . In this case, water passes through the flushing pipe  3  into the toilet pan  5 . The quantity of water used here is controlled via the control means  26  and the signal line  27 . One or more nozzles are preferably provided for spraying the inside  5   b  of the toilet pan  5 . 
   Following spraying, the piston  10  moves approximately into the position shown in FIG.  4 . The uppermost position is preferably not quite reached here. Since the valves  7  and  16  are still closed, a negative pressure which is preferably less than, for example, 0.5 bar is thus produced in a chamber  12 ′. At the same time, further flushing of the toilet pan  5  can be triggered via the control arrangement  26 . Approximately simultaneously, the valve  7  is opened comparatively quickly, and thus essentially abruptly. The quick opening may be brought about, for example, by a prestressed spring (not shown here). Approximately simultaneously, flushing of the toilet pan  5  is interrupted. The bottom chamber  12 ′ is large enough to be filled approximately half with air and half with suction-extraction substance  4 . When the substance  4  is extracted by suction, the solids are reduced in size by suddenly flowing into the bottom chamber  12 ′, with the result that the substance  4 ′ extracted by suction is present in a state similar to a suspension. In  FIG. 5 , the arrow  28  shows the direction in which the substance  4  flows into the bottom chamber  12 ′. Located above the substance  4 ′ is an air cushion  21  which, as has been mentioned above, takes up approximately half the volume of the bottom chamber  12 ′. 
   Once the substance  4  has been extracted by suction, then the valve  7  is closed and the piston  10  moves downward, the air cushion  21  being compressed and a positive pressure of, for example,  2  bar being produced. The valve  16  is then opened and, as a result of the positive pressure, the substance  4 ′ is expelled into the pressure line  17  and, finally, into the waste-disposal conduit  18 . The valve  16  is then closed. When the piston  10  is moved downward, fresh air from the ambient air is directed into the top chamber  13  via the valve  22 . The pressure line  17  is usually filled, at least in part, with suction-extraction substance  4 ′. In order for this substance to be expelled as well, a second flushing operation is preferably triggered. In this case, the toilet pan  5  is flushed again and this flushing water, by means of the operation explained above, is taken in and then expelled. By virtue of this further operation, the pressure line  17  is flushed through with water and cleaned at least in part. This further flushing water passes into the waste-disposal conduit  18 . 
   The suction line  6  opens out preferably tangentially and preferably also downward into the pressure chamber  12 . This results in particularly favorable dynamics for the suction-extraction substance  4  and thus the flow of this substance  4  in and out of the cylinder  8 . The substance  4  flows tangentially, and in a downwardly directed manner, into the pressure chamber  12  and thus, as it were, flushes the cylinder  8  and rotates in the pressure chamber  12 . The substance  4  is then expelled. Since everything is in motion, it is possible to avoid deposits in the pressure chamber  12 . Particles which are nevertheless deposited are flushed up again. Contact with the piston  10  and the seal is largely avoided.