Drainage systems in civil or industrial buildings are known to be constructed of piping of synthetic material run along inside walls and under floors.

If a break or blockage occurs in one part of the system, walls or floors, even if in perfectly good condition, must therefore be opened up for inspection, repairs or replacement of parts

This interference with finished surface material, often of a valuable kind, involves considerable expense over replacement. Matching materials to avoid repair work being noticeable may be a difficult matter. If marble, stonework, wood or other expensive materials are concerned, it may be almost impossible to find similar ones to main¬ tain unaltered the characteristics of those first used. Purpose of the present invention is to provide a drainage

system for sewer water using piping as reliable as that at present in use, but so placed as to permit easy in¬ spection, and replacement of damaged pipes were needed, without having to break into walls and flooring. Subject of the invention is a drainage system for sewer water from civil and industrial buildings comprising box-shaped traps for connection to the lavatory bowl, distribution boxes for joining up the various parts, drain boxes for baths and showers, washbasins and bidets, and piping to connect them all, created by separating the system into two distinct parts, one inside the other. The external system is fixed, having been definitively installed within the structure of the building, and con¬ nects orifices - fitted with pipe unions - placed in the structure to meet the drains leading off from the lavatory bowl and from other pieces of sanitary equipment. The internal system is shaped like the external one, is placed inside it and it too is connected through orifices in the building structure and by means of special connec- tions, to the lavatory bowl and to the other sanitary equipment .

The internal system differs in size from the external one and contains fittings to facilitate its installation in¬ side said external system and, where necessary,make pos- sible its partial or complete removal, or replacement.

In the sides of the box traps are orifices, those in the fixed box trap being aligned with those in the internal replaceable box trap; they also have connections forfpi- ping and a cover flush with the surface of the building structure; if required this may be sunk to allow space for a layer of finishing material similar to that of said structure .

The piping, of synthetic material, is flexible and has helical undulations that form external and internal thread¬ ing, pipes for the replaceable system being placed inside said fixed system. Fittings on said traps, forming part of the fixed system, consist of external cylindrical pipe unions on the orifi¬ ces, having external threading corresponding to the in¬ ternal threading on the fixed pipes forming the fixed sys¬ tem to permit unions and pipes to be coupled togebher. Connections to the traps in the replaceable system consist of pipe unions inside their orifices, internal taper con¬ verging on the inside, with external threading on the out¬ side onto which a washer is to.be.-screwed , said washer ha¬ ving a cylindrical axial body surrounded by a head in which a cylindrical cavity is threaded with the same thread as that of the pipe unions.

Packing inside the pipe unions partially projects inwards in the box trap, its external taper corresponding to that of said orifices, and its internal diameter corresponding to the external diameter of the piping forming part of the replaceable system.

It follows that by screwing on the washer said packing, forced inside the pipe union by the opposing tapers, holds the piping firmly against the axial body of the washer by means of its thread, so making a stable connection.

Fittings on the orifices, in the building structure, form¬ ing part of the fixed system, consist of a cylindrical coupling whose external thread is the same as the internal thread on the fixed pipes; said coupling is to be placed inside the structure and comprises a perforated head of greater diameter which makes contact with the external surface of said structure.

The pipe is in this way fixed to said coupling by the thread .

The hole in the above head is larger than the maximum diameter of the piping in the replaceable system to al- low said piping to emerge freely outside the building structure .

Alternatively the fittings on the orifices in the build¬ ing structure of the fixed system consist of an internal¬ ly threaded cylindrical coupling, said internal thread being the same as the external thread on the fixed pi¬ ping; said coupling is placed inside the structure and is fitted with.a flange that makes contact with the ex¬ ternal surface of said structure. In this way the fixed piping is connected to said coup- ling by means of its thread, while the piping in the re¬ placeable system freely emerges from the building structure. Pipe fittings for the sanitary equipment - bath, wash basin, bidet and others - consist of a coupling fixed to the drainpipe union of said sanitary equipment, having an external . hread to receive a threaded lock ring and having one end whose external diameter corresponds to the smaller internal diameter of the piping in the replace¬ able system . Inside said lock ring is a threaded hole by which said ring can be screwed onto the coupling; said hole ends in a flaired taper that houses packing with a correspond¬ ing taper on its outer surface, and an inner cylindrical hole whose diameter corresponds to the maximum diameter of the piping in the replaceable system. The lock ring is externally threaded and to this is screwed a washer in which there is an axial hole through which the piping passes.

Therefore, by screwing on said washer, the packing when forced inside the coupling, due to the opposing tapers, holds the piping firmly to the coupling and so makes a stable connection. The fitting on the drain to the lavatory bowl consists of a ring nut whose internal thread corresponds to the external thread of the piping in the fixed system, with a flat flange to connect with the flooring, and of pack¬ ing in which there is a hole whose diameter corresponds to the external diameter of the drain pipe union for said lavatory bow ^' l , the maximum external diameter being greater than the internal diameter of the flange, and with an internal axial helical annular groove corres¬ ponding to the dimensions and shape of the piping in the replaceable system.

It is therefore possible to fix the piping in the fixed system by screwing its external thread onto the thread of the ring nut, and to fix the piping in the replace¬ able system by fitting its end into the helical groove in said packing.

The lavatory bowl drain pipe comprises an original part in which there are orifices which have an external thread corresponding to the internal thread on the piping in the replaceable system. Said piping can therefore be fixed by screwing the thread on the fitting into the internal thread of said piping. Said original part is connected to the upper part next to it by means of a concertina-type flexible connection so as to allow for any change of shape in the lavatory bowl drain pipe, as well as to facilitate replacement of said original part.

The drain traps for the bath or shower and for the other pieces of sanitary equipment have connections similar to those of the other box traps making connection possi¬ ble, by means of two orifices, onto the drain pipe of the lavatory bowl and to the overflow pipe respectively, while plugs to holes in the sanitary fittings are worked by a tie rod inside the piping that connects said box trap to the overflow. The advantages of the invention are clear. The fixed external system assumes the form of a simple

"sheath" or suppo'rting structure for the replaceable sys¬ tem whose functions are equivalent to those of systems at present in use . In the event of a breakage or blockage, not only is inspec- tion made quick and easy, but also damaged parts, or even the whole internal system, can be replaced.

This can be done without any damage to wall or floor finish¬ ing material which in this way are not subjected to the slightest strain or stress. In prefabricated buildings, the component parts of the fixed system in particular, can be installed during building. The replaceable system can then be put in after the struc¬ tural parts have been given their permanent positions. All this means considerable savings should repaires become necessary, offering as well aesthetic advantages inconcei¬ vable with present systems, economy in overall costs since installations of the replaceable system, after masonry work has been completed, avoids damage and facilitates the work. Characteristics and purposes of the invention will be made still clearer by the following examples of its execution illustrated by diagrammatically drawn figures.

Fig. 1 Perspective view of the drainage system for sewer water from a bathroom, according to the invention. Fig. 2 Longitudinal section of the box trap of the system with fitting to the drainpipe of the lavatory bowl. Fig. 3 A partially cut away plan view of the box trap. Fig. 4 Detail of the box trap in Fig. 2.

Fig. 5 Longitudinal section of a wall drain for a wash basin. Fig. 6 Longitudinal section of a lavatory bowl drain pipe in the wall from a flush tank above. Fig. 7 Longitudinal section of the box trap for a bath tub. Fig. 8 Cut through plan view of the bath drain box trap. Fig. 9 Longitudinal section of the distribution trap. Fig.10 Plan view of the distribution trap.

Fig.11 Longitudinal section of the drain from the lavatory bowl, and pipe union for said drain pipe.

Fig.12 Cut through plan view of the lavatory bowl drain.

Drainage system for a bathroom 10 showing the floor 11 and wall 12, said system consisting of two parts, one fixed 15 permanently installed in the structure of the building, and another replaceable 16 inside the fixed one.

The fixed system 15 comprises a parallelepiped box-shaped trap 30 with four orifices 31-34 one on each of its four sides, each orifice with pipe fittings 41-44 for connection to the lavatory drain 70 through piping 102-104 to the other pieces of sanitary equipment 22-24.

Said box trap is closed by the cover 37 on the intermediate frame 38 and by screws 29.

The cover has a raised edge 39 flush with the floor 12. In this way, by laying over said cover 37 finishing mate- rial 17, the same as the finish 18 on the floor 12, the cover can be almost completely hidden.

On the flexible pipes 102-104 are helical undulations and these create internal and external threading. The pipe fitting 41 on the orifice 31 comprises a conver¬ ging tapering pipe union 60 on which is a flange 61 with holes 62 passing through it. The lavatory bowl drain 70 comprises superimposed parts

71 and a part 72 fitted with a pipe union 73 and flange 74. In said flange are threaded holes 75 aligned to the holes

62 in the flange 61, the two flanges being joined by screws

63 and packing 65. Pipe fittings 42-44 comprise a cylindrical pipe union 35 with an external thread 36 corresponding to the internal thread on the pipes 102-104.

The pipes 102-104 join the pipe fittings 42-44 respective¬ ly to the fitting 45 on the drain 140 for the bath 22 and to the fittings 46 and 47 on the wall 12 of the bathroom 10.

These wall fittings 46 and 47 have a cylindrical pipe union 120 fixed to the centre of the semispherical cap 122 whose external thread 121 corresponds to the internal thread on pipes 103 and 104 and whose internal diameter 123 corres- ponds to the external diameter of the pipe 113.

Wall fittings 50 and 51 are similar to fittings 46 and 47 and have a cylindrical pipe union 130 with external thread 131, mounted inside the wall 12 stably connectable to the collar 133 of the semispherical cap 132. The axis of said collar passes through the centre of the cap 132, inclined in relation to its diametral plane at about 45°. By means of these fittings connection is made between the externally mounted flushing tank 26 and the lavatory bowl 25 by the fixed pipe 106, and between fit- tings 52 and 53 by the replaceable pipe 116.

Said fitting 53 comprises the packing 195 whose thread 196 corresponds to the thread on the pipe 116.

The replaceable system 16 inside the fixed system 15 com¬ prises the parallelepiped box trap 80 that can be fitted inside the fixed box trap 30 resting on the supporting ribs 76 and 77. In the box trap 80 there are four orifices 81-84 corres¬ ponding to the orifices 31-34 in the fixed box trap 30 and four fittings 91-94; these connect to the lavatory bowl drain pipe 70 and, through pipes 112-114, to the other pieces of sanitary equipment 22-24. Eitting ;91 on the orifice 81 comprises a cylindrical pipe union 55 the taper of whose external wall 56 corresponds to the taper of the pipe union 60 on the box trap 30 and can make a watertight connection to said union 55 by means of the tapered packing 57 comprising a flange 58. The fittings 92-94 comprise a diverging tapered ^* pipe union 85 with a cylindrical external wall and thread 86, on which the washer 87 is screwed, the internal thread 88 of said washer corresponding to the thread 86 of the pipe union; said fittings also comprise an axial tubular body 89.

The external diameter of said body corresponds to the in¬ ternal diameter of the pipes 112-114 _r to:.be _^ placed. inside the. fixed pipes 102-104; though similar to said fixed pipes, external .diamatei..of tpipes . il2-1-L4.is smaller than the internal diameter of the fixed pipes so that the" former can be easily run inside the latter and replaced if this should become necessary.

Between the pipe union 85 and the washer 87 is packing 66; the internal wall 67 of said packing corresponds to the external diameter of pipes 112-114 and its external wall 68 tapers to correspond with the taper of the pipe union 85.

The framework 38 below the cover 37 corresponds, to the.: space between the fixed box trap 30 and the replaceable one 80. Packing 40 is placed between the lid 37 and said replace¬ able trap 80. Through the wall connection 46, the washbasin 23 is joined to the box trap by the pipe 113 and pipe fitting 48. Said pipe fitting 48 comprises a coupling 170 and flange 171 to fit said coupling on the edge of the hole 28 in the wash basin, said flange having an external thread 172 onto which the ring nut 175, with internal thread 176, is screwed. Said ring nut 175 ^' has an internal tapering connection 178 and a second external thread. 177 on the free end. Inside said tapered connection is a packing 180, tapered externally, through which is an axial hole to allow the pipe 113 to pass.

The washer 181 is screwed onto the thread 177, said washer having through it an axial hole to allow passage of the pipe 113, and an internal thread 182. Screwing pressure by the washer and opposing tapered sur- faces cause the packing to contract and thus maintain a hold on the pipe 113 pressed between said packing and the coupling 170.

The fitting 52 under the flushing tank 26 comprises the pipe union 190, ring nut 191, washer 192, packing 193 all substantially the same as the coupling 170, ring nut 175, washer 181 and packing 180 of fitting 51 already .described. Fitting 53 on the lavatory bowl 25 for water from the flush¬ ing tank 26 comprises the pipe union 27 for said lavatory bowl, packing 195, whose internal thread 196 corresponds to the external thread on pipe 116, and locking flange 198. The fixed trap 140 for the bath 22 has opposite orifices 141 and 142 with pipe fittings 45 and 54 similar to the

fittings 42 and 44 previously described.

Fixed pipe 105 connects fitting 54 to overflow 153 ^J through fitting 55.

Inside the box trap 140 is the replaceable box trap 150 held in place by screws 153 that screw onto the threads 154 present at the bottom of the fixed trap 140. In said replaceable trap 150 are orifices 151 and 152 aligned with the orifices 141 and 142 in the fixed trap 140, said orifices having fittings 56 and 57 similar to those, 42-44, already described for the replaceable pipes 112 and 115.

As figures 7 and 8 show, in the hole 28 at the bottom of the bath 22 is a trap 155 comprising an upper flange 156 that fits against the edge of the drain hole 28 in the bath 22, and the column 157 with lower head-pin 158 in¬ serted in the seat 159 at the bottom of the trap 150. The column 157 supports the pin 160 of the bath plug 161 and the device 162 for working said plug by means of a tie rod 163 placed inside the replaceable pipe 115 and connected to the overflow 153.

To connect up with other parts, pairs of box traps like those indicated by numbers 220 and 230 in Figures 9 and 10, can be included in the system 10. The main features of said box traps are the same as those of the pair of box traps, namely the fixed one 30 and the replaceable one 80, already described.

The orifices 221-224, pipe fittings 225-228 and cover 239 over the trap 220 forming part of the fixed system, can be seen, as well as the orifices 231-234 and pipe fittings 235-238 for the replaceable trap 230 similar to the ori¬ fices 31-34 and 81-8A and to pipe fittings ,41-44 already

described. Connections are made by pipes 108 and 118 similar to those described above. The figures show the cover 239 flush with the level of the floor 12. Connection between the lavatory drain pipe 70 and lava- tory bowl itself 25, can be made through the fixed pipe 107 that joins the fixed horizontal fitting 200 to the vertical fitting 201 under the floor 12 (Figs. 11, 12). Said fittings have a washer 202 with internal thread 203 corresponding to the external thread on pipe 107, and with a flange 204 adhering to the vertical structure 13 and to the floor 12 respectively. The lavatory bowl pipe 70 includes the special part 205 which has four orifices 206 with pipe unions 207 whose external thread 208 corresponds to the internal thread of the pipes 117. Said pipes 117 are connected to pipe unions 206 by annular packing 213 and metal clips 214.

Said special part 205 is connected to the upper part 72 and to the vertical pipe union 76 by a concertina-type_of flexible coupling 209 held in place by metal clips 215. The replaceable pipe 117, similar to pipes 112-114 referred to earlier, connects a pipe union 206 to a pipe union 2 7 on the lavatory bowl 25 by packing 210. Cross section of said packing is trapezoidal with a hole 211 in it whose position corresponds to that of the inner wall of the union 27 of lavatory bowl 25, and an inner helical groove 212 onto which pipe 117 is screwed, as seen in Fig.11. Flexible coupling 209.absorbs any movement by the lavatory drain pipe so that special part 205 can be replaced. Clearly ; therefore , the whole system 16 can be replaced as the replaceable box traps can be lifted out from-the fixed ones by simply taking off the covers, and since the connect¬ ing pipes can be pulled out completely and easily.