Patent Publication Number: US-7908685-B2

Title: Water trap for sanitary appliances

Description:
This is a national stage application of International Application PCT/BE2005/000186 filed 21 Dec. 2005, claiming priority from Great Britain application no. 0428401.4 filed 24 Dec. 2004, the disclosures of which are incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to water or liquid sealing traps such as used to connect the waste water outlet of a wash-basin, sink or the like to a waste water drainage system. 
     2. Description of the Prior Art 
     It is generally known that a permanent water seal is required in the water trap to assure the normal function of a waste water outlet installation and to prevent contaminated air from the sewer from contacting the surrounding atmosphere. 
     A water trap of this kind may be U shaped with one leg connected to a sanitary appliance, such as a wash basin or the like, and the other leg connected to the waste water system. Another embodiment of the water trap may be in the shape of a bottle-like container, in the centre of which extends a vertical pipe connected to the water basin and having an outlet for connection with the waste water pipe. 
     Existing water traps of the two kinds have been provided with an air admittance valve in order to eliminate negative air pressure which may occur in the drainage system, especially when flushing down an amount of waste water through the vertical parts of the waste water pipes. In such cases air suction may be such that the water contained in the water traps is sucked away, breaking the water seal. 
     A U-shaped water trap provided with an air admittance valve has already been disclosed in U.S. Pat. No. 605,202 which is related to a trap for sinks, the outlet pipe of which being provided with a valve that seats itself by gravity. This air admittance valve is extending upwards from the outlet pipe which diminishes the available space around the water trap and which is positioned in such a way that it may be accidentally tampered and damaged preventing the normal working of the valve. 
     The patent documents GB 856.064 and GB 1.220.982 also refer to water or liquid sealing traps provided with air admittance valves. In the first document the valve is either applied to the outlet leg of a U-shaped version of the trap and the inlet leg is connected to a wash basin or the like or to the cylindrical head of the container in a bottle shaped version. In this case the non return air valve is fitted on the side opposite the outlet pipe to the sewer. In both cases the position of the valve is an obstacle to easy fitting of the water trap in a generally confined spaced. 
     Document GB 1.397.705 discloses a bottle shaped trap with a non return valve provided inside the water trap body and more precisely in a separation wall between the inlet area and the outlet pipe above the static liquid level. The port by-passing the liquid seal and the valve includes means whereby it is normally held closed but opens upon suction in the outlet pipe to admit air from the inlet area to break the suction. In this case the valve is not protruding the outer configuration of the water trap but is situated in an area where it is constantly subject to (waste) humid atmosphere and sediment of waste water passing through the water trap, causing clogging of the valve membrane. 
     Finally, document GB 2 005 749 discloses a water trap of the bottle shaped version including an annular air admittance valve situated in the upper portion of the container. In this case the valve is completely separate from the waste water flow, but the overall dimensions of the container and valve is rather important, especially in confined spaces. 
     SUMMARY OF THE INVENTION 
     The present invention provides means eliminating the drawbacks outlined here above whereby the water trap has minimum overall dimensions while maintaining or even improving the water flow capacity and lowering the required maintenance frequency of the water trap. 
     The present invention further allows for the water trap embodiment to be covered by a suitable jacket adapted to the design and materials of the sanitary appliance. 
     According to the present invention, the water trap is configured and provided with means which include a housing having an upper portion provided with an inlet opening adapted to receive the outlet pipe of a sanitary appliance. A central portion is provided which is adapted to be connected to the upper portion, and is provided with a cylindrical passing through space or passage. The outlet opening is adapted to be connected to an evacuation pipe of a drainage system situated in a lower extension of the central portion, and to a valve housing. The valve housing is situated in the upper part, and incorporates an air admittance valve. The housing also includes a lower portion connected to the central portion. The air admittance valve is situated at one side of the upper part of the central portion adjacent to the cylindrical space and is located above the outlet opening, leaving an air admittance area located between the lower part of the air admittance valve and the upper surface of the outlet opening. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       An embodiment of a water trap according to the invention will be described hereafter, by way of an example only, with reference to the accompanying drawings, in which: 
         FIG. 1  is side view of a water trap according to the invention; 
         FIGS. 1A ,  1 B and  1 C are respectively, a top view, a bottom view and a front view of the water trap according to  FIG. 1 . 
         FIG. 2  is a vertical cross section view along the centre of the water trap represented in the  FIG. 1 ; 
         FIG. 2A  is an enlarged horizontal cross section view about the line A-A in  FIG. 2 ; 
         FIG. 2B  is a detailed view of the assembling between a separation wall extending from the central portion and the guiding/tightening means of the lower portion; 
         FIG. 3  is a partially cut out side view of the central portion of the water trap according to  FIG. 1 ; 
         FIG. 4  is a side view of the lower portion of the water trap according to  FIG. 1 ; 
         FIG. 5  is a vertical cross section view of a water trap according to the invention provided with a jacket; 
         FIG. 6  is an exploded perspective view of the jacket according to  FIG. 5 ; 
         FIGS. 7 and 8  are bottom views of possible shapes of the jacket according to the  FIG. 5 . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In  FIG. 1 , a water trap is shown, of a general U-shaped kind, which consists of an housing  1 , including a lower portion  2  or bowl in which the water trap can be formed, a central portion  3 , adapted to be connected to the lower portion  2  and an upper closing portion  4 . 
     The upper portion  4  is provided with an inlet opening  5  adapted to receive the outlet pipe  6  of a water basin or the like. As can be seen in  FIGS. 2 and 3 , adjacent to the inlet opening, the inner side of the upper portion  4  is provided with guiding means  7  arranged to co-operate with a normally closed membrane  8  of an air inlet valve which is advantageously incorporated to assure efficient function of the water trap. 
     As shown in  FIG. 1A , the shape of the upper portion  4  of the water trap is oblong, the smaller dimension of which corresponds approximately to the diameter of the outlet pipe  6  and the larger dimension corresponds with about twice said diameter. One major half portion of the upper portion  4  represents the opening  5  and the adjacent portion covers mainly a housing  11  with the membrane  8  of the air admittance valve. Said portion also contains downwardly extending guiding means co-operating with the membrane  8 . 
     The shape of the membrane  8  will advantageously be cup or U shaped in order to reduce the total height of the housing  1  and to leave sufficient space for the guiding means  7 . 
     The central portion  3  of the water trap has an horizontal section which corresponds with the shape of the upper closing portion  4 . During assembling of the components of the water trap, the closing portion  4  is fixed to the upper side of the central portion  3 . 
     Accordingly, the central portion  3  is provided with a cylindrical space  10 , extending vertically and adapted to receive the outlet pipe  6  of the water basin, or the like, which is passing through the inlet opening  5  of the upper portion  4 , as shown in  FIGS. 2 and 3 . 
     Adjacent to the cylindrical space  10 , the central portion  3  is provided, in an upper part, with a valve housing  11  constituting an air admittance valve and, in a lower part, with an outlet opening  12  situated in a lateral extension from the central portion  3 , said outlet opening  12  being located underneath the housing  11  of the air admittance valve. 
     The valve housing  11  is built in such a way that it forms an air admittance area  17  between its lower part and the upper surface of the outlet opening  12 . Said lower part forms a valve seat  9  on which rests the membrane  8  in closed position, by gravity only, and which leaves a space  18  between the seat  9  and a vertical wall  19  defining the cylindrical space  10  of the central portion  3 . 
     The outlet opening  12  is adapted to co-operate with a pipe  13  connected to the drainage system and is provided about its centre with an horizontal partition wall  14  which is situated about the centre line of the opening  12  and dividing said opening into completely separated conduits, one upper conduit  15 , above the partition wall, to allow air inlet flow from the air admittance valve when negative pressure occurs in the drainage system and one lower conduit  16 , beneath the partition wall, to allow the waste water to be evacuated into the pipe  13  of the drainage system. 
     The air inlet flow through the upper conduit  15  emerges into the outlet opening  12  by means of a venturi shaped upper wall of the opening  12  improving the air flow capacity. The waste water flow through the lower conduit  16  emerges into the outlet opening  12  by means of a venturi shaped lower wall of the opening  12  improving the water flow capacity. 
     The conduit  16  is provided, in its lower part, with a restriction in the shape of an overflow rim  32  towards the evacuation pipe  13 . The level of said overflow rim  32  is situated above the lowest level of the evacuation pipe  13 . 
     In case of negative pressure in the drainage system, the membrane  8  will automatically lift from its seat  9  and atmospheric air will be able to flow into the water trap via the space  18  and the upper conduit  15  towards the evacuation pipe  13  and the drainage system. 
     According to the invention, the vertical wall  19  of the central portion  3  extends downwards to form a separation wall  20  adapted to co-operate with vertical guiding and tightening slots  21  provided laterally on both inner sides of the lower portion  2  ( FIG. 2A ). 
     Said lower portion  2  has the outer shape of an oblong cup formed by two intersecting cylindrical walls the intersecting parts being left out to create a space provided for the separation wall of the central portion  3 . The guiding and tightening slots  21  are provided in the inner lateral intersection area of said cylindrical walls and the separation wall  20  leaves sufficient space between its lower part and the bottom of the lower portion  2  to allow full capacity of the waste water flow to be evacuated. 
     The actual water trap seal is formed between the upper level of the rim  32  and the lower extremity of the separation wall  20 . The distance between those levels constitutes the height of the water trap seal which can be adapted to existing standards relating to the height of the water trap, the separation wall  20  being always situated below the water level of the water trap. 
     In fact the water trap according to the present invention has not a U shaped body but the U shaped pattern of the water seal itself is only obtained by the cylindrical intersecting side walls of the lower portion  2  in combination with the separation wall  20  extending downwards from the central portion  3 . Accordingly, it is important that the lateral side walls of said separation wall  20  co-operate with the guiding means  21  in such a way that it becomes a water tight connection (see  FIG. 2B ). 
     In order to improve the working of, and to avoid frequent maintenance of, the water trap, the bottom of the lower portion  2  is provided with deflection walls  22  restricting the water flow in the bottom of the lower part  2  in order to increase the velocity of the water flow and to evacuate waste deposit in the water trap. 
     The lower portion  2  will be advantageously fixed to the central portion  3  by any suitable means. In the embodiment shown on the enclosed drawings  1 ,  2 A,  3  and  4 , the lower portion  2  is fixed to the central portion by means of screws  23  adapted to fit into holes  24  of the central portion  3 . According to the shown embodiment, the fixing means or screws  23  are situated in the central area of the intersecting cylindrical walls in order not to protrude beyond the outer lateral surface of the water trap housing  1   
     The contact surfaces between the lower surface of the central portion  3  and the upper surface of the lower portion  2  will advantageously be provided with sealing means such as a flange joint or an O-ring to avoid leakage between the two parts. 
     When evacuating waste water from the water basin, the water will flow through the outlet pipe  6  directly into the lower portion  2  of the water trap. The waste water will flow via the bottom of the lower portion  2  and the deflection walls  22  and between the partition wall  14  and the overflow rim  32  towards the evacuation pipe  13 . 
     Upon stopping of the waste water flow, a water trap will be built up in the lower portion  2  of the water trap according to the invention and partly in the central portion  3  up to the level of the overflow rim  32 . In case of negative pressure in the drainage system, the membrane  8  of the air admittance valve will lift up temporarily and allow air flow to enter the system via the space  18  and the upper conduit  15  above the partition wall  14  towards the evacuation pipe  13 . 
     An advantage of the water trap, according to the invention, is in the fact that the outer configuration is particularly suitable to be covered by a jacket  25  such as the one illustrated in  FIGS. 5 to 8 . 
     Said jacket  25  can be maintained onto the water trap  1  by means of a closing member  26  adapted to be installed in the upper region of the water trap. For this purpose this member  26  is provided in a horizontal part with an opening  27  suitable to match with the inlet opening  5  of the water trap  1  and in a vertical part with a half cylindrical opening  28  suitable to match the central portion  3  at the rear part of the outlet opening  12 . 
     The jacket  25  itself covers almost the entire embodiment of the water trap  1  and is provided on the backside with an opening and an half cylindrical opening  29  suitable to match the central portion  3  at the rear part of the outlet opening  12 . 
     Different means can be proposed to maintain the jacket and the closing member together. In the embodiment shown in  FIG. 6 , such means could be flexible members  30  of the closing member  26  engaging corresponding apertures  31  in the jacket  25 . 
     As shown on  FIGS. 6 and 7 , the jacket  25  has a substantial rectangular horizontal cross section with a cylindrical shaped front portion in order to lose a minimum of available space. 
     The jacket could also have a clear rectangular horizontal cross section such as shown in the bottom view of  FIG. 8 . 
     The main advantage of the present invention is to provide a water trap device, provided with an air admittance valve, with minimum overall dimensions which is most appreciated in general confined or restricted spaces. 
     Another advantage of the present invention is the fact that, due to said minimum overall dimensions, it becomes possible to provide the water trap with a suitable cover in the shape of a jacket adapted to match with the design, material or colour of the sanitary appliance to which it is connected. 
     Despite the fact that only one embodiment of the water trap structure, according to the present invention, has been described in detail here above, various changes and modifications may be made without departing from the scope of the invention. 
     LEGENDS OF THE REFERENCES ON THE FIGURES 
     
         
           1 . housing of the water trap 
           2 . lower portion 
           3 . central portion 
           4 . upper portion 
           5 . inlet opening of the water trap 
           6 . outlet pipe of the sanitary appliance 
           7 . guiding means of the air admittance valve 
           8 . membrane 
           9 . seat of the valve 
           10 . cylindrical space 
           11 . valve housing 
           12 . outlet opening of the water trap 
           13 . evacuation pipe 
           14 . partition wall 
           15 . upper conduct of the outlet opening 
           16 . lower conduct of the outlet opening 
           17 . air admittance area 
           18 . space between air admittance valve and cylindrical space  10   
           19 . vertical wall 
           20 . separation wall 
           21 . guiding slots 
           22 . deflection walls 
           23 . screws 
           24 . holes 
           25 . jacket 
           26 . closing member 
           27 . opening 
           28 . half cylindrical opening of closing member 
           29 . half cylindrical opening of the jacket 
           30 . flexible members 
           31 . apertures 
           32 . overflow rim