Patent Publication Number: US-2015086665-A1

Title: Plant for the production of a concrete body

Description:
The invention relates to a method for the production of a concrete body according to the preamble of patent claim  1  as well as to a plant for the production of the concrete body according to patent claim  5 . 
     A method is known (DE 35 22 846 A1) for the production of concrete roof tiles using the extrusion method, in which onto a lower mold delivered in a continuous strand to a coating installation a layer of green concrete is applied and the concrete is subsequently compacted and profiled by means of a shaping roller and smoother. The green concrete layer thus compacted is subsequently cut into individual roof tiles in a cutting station. Since the green concrete utilized for the production of the roof tiles has a relatively large sand grain size, the roof tiles have a rough porous surface. The surface of the roof tiles is therefore provided with a color coating to seal and smooth it. 
     For further improvement of the surface quality in roof tiles, production methods have been developed in which the roof tile is provided with a fine-grained mineral surface layer. Such a method is described for example in DE 39 32 573 C2. Herein, first, from a coarse-grained green concrete mixture a roof tile is extruded whose upper side is subsequently provided by a profiled smoother with a multiplicity of flutes extending in the longitudinal direction of the roof tile. Onto the surface of the roof tile subsequently a coating of a very fine-grained green concrete is extruded which lends the roof tile a surface layer with a very smooth surface. The flutes are retained since they serve to effect a mechanical grip between the roof tile and the coating. However, the known method entails complex production engineering since the roof tile and the surface layer is produced of two different green concrete mixtures with sand grains of varying fine grain size. 
     U.S. Pat. No. 4,666,648 A also discloses providing the upper side of a roof tile with a profile. However, the profiling here takes place for different purposes. In U.S. Pat. No.
     4,666,648 A a method is disclosed for the production of roof tiles, in which, by means of an irregularly profiled profiling unit, a profile is applied on the upper side of the roof tile. This profile consists of several grooves one next to the other and oriented in the longitudinal direction, which imitate a wood grain pattern. Onto this roof tile, subsequently brown coloring agent is applied such that the roof tiles thus produced have the appearance of wood shingles.   

     A method is furthermore described in which onto the upper side of a roof tile grooves are applied as a decoration (JP 2000-328721 A). Smoothing of the roof tile after the grooves have been applied does not take place. 
     The present invention therefore addresses the problem of providing a concrete body produced of extruded green concrete, comprising only one concrete mixture which has a very smooth surface as well as high surface quality and which is simple of production. 
     This problem is resolved according to the features of patent claims  1  and  5 . 
     The method according to the invention dispenses with the production and the separate application of a fine-grained concrete mixture as a surface layer. For the production of the roof tile only one green concrete mixture is utilized. The improvement of the surface quality is attained thereby that a method for the production of a concrete body with a flat upper side is provided. From green concrete a concrete body is herein extruded which is provided by a profiling unit with a groove profile on its upper side. By means of the profiling unit and as a function of its profile, the separation of the sand particles according to particle size takes place, wherein large sand particles are displaced from the surface region of the concrete body inwardly, which means into the interior of the concrete body. Only fine sand particles can pass the profile, whereby on the surface of the concrete body a groove profile with elevations is formed. These elevations of the groove profile are comprised of fine-grained concrete. The upper side of the concrete body is subsequently smoothed by means of a levelling unit. The elevations are herein squashed whereby the fine-grained concrete of the elevations is distributed and forms a surface layer. 
     The invention also relates to a plant for the production of a concrete body with such a flat upper side. The plant comprises a working station with an extrusion arrangement for the extrusion of a concrete body of green concrete and a profiling unit downstream in the extrusion direction for generating a groove profile on the upper side of the concrete body, the profiling unit having a profile with webs extending parallel to one another in the extrusion direction. Via an interval distance b of the webs with respect to one another, a limit value for size-dependent separation of the sand particles is predetermined. The plant also comprises a levelling unit for smoothing the profiled upper side of the concrete body. 
     By smoothing out the upper side of the concrete body, the fine-grained concrete becomes very uniformly distributed and a smooth surface layer is formed in which the air inclusions or pore formations are avoided due to the high packing density. In comparison to the concrete bodies known from DE 35 22 846 A1, the concrete bodies produced according to the invention therefore have a markedly decreased surface roughness. The quantity of the coloring agent application can be considerably reduced due to the lesser surface roughness. 
     For as smooth a surface of the concrete body as possible, DE 39 32 573 C2 discloses utilizing a concrete mixture with a very fine-grained sand. The use of such sands has the disadvantage that the concrete mixture tends to the formation of bubbles and therewith to increased porosity. With the method according to the invention, in contrast, concrete mixtures with very fine sands can also be processed, for during the separation of the sand particles through the profiled profiling unit these sand particles are moved whereby venting of the concrete mixture takes place. After the smoothing of the upper side of the concrete body, a concrete body is obtained which has a very smooth, that is a flat, surface layer. 
    
    
     
       An embodiment example of the invention is depicted in the drawing and will be described in further detail in the following. In the drawing show: 
         FIG. 1  a top view onto a finished concrete body; 
         FIG. 2  a section A-A through the concrete body depicted in  FIG. 1 ; 
         FIG. 3  an enlarged segment of the segment [sic: section] of the concrete body depicted in  FIG. 2 ; 
         FIG. 4  a side view of a portion of a plant for the production of concrete bodies; 
         FIG. 5  a perspective view of an underside of a profiling unit; 
         FIG. 6  a segment of the profiling unit depicted in  FIG. 5 ; 
         FIG. 7  a segment of a variant of the profiling unit depicted in  FIG. 5 ; 
         FIG. 8  the application of a groove profile onto a concrete body; 
         FIG. 9  the levelling of the groove profile disposed on the concrete body according to  FIG. 8 ; 
         FIG. 10  the concrete body depicted in  FIG. 2  with groove profile before the levelling. 
     
    
    
       FIG. 1  shows a top view onto the upper side  1  of a finished concrete body  2  with head-end section  3 , central section  4  as well as a foot-end section  5 . This concrete body  2  has the shape of a roof tile, for example the shape of a Frankfurt pan. The concrete body  2  comprises a cover fold  6 , a center brim  7  and a water fold  8 . Between the cover fold  6  and the center brim  7  as well as between the center brim  7  and the water fold  8  a water course  9 ,  10  each is disposed. As described for example in DE 10 2005 011 201 A1, in the water courses  9 ,  10  a water barrier can be disposed. Such a water barrier, however, is not depicted in  FIG. 1 . 
     On the underside  11  of the concrete body  2  two cover fold ribs  12 ,  13  are disposed. These cover fold ribs  12 ,  13  can engage into a water fold of a second concrete body when a roof is laid with the concrete body  2 . However, this is not shown in  FIG. 1  for the sake of simplicity. The water fold  8  of the concrete body  2  has several water fold ribs  14 ,  15 ,  16 . Into these water fold ribs  14 ,  15 ,  16  of the concrete body  2  cover fold ribs of a further concrete body can be disposed. Through the cover fold  6  and the water fold  8  it becomes possible to dispose the concrete bodies with precise fit onto one another when laying a roof. 
       FIG. 2  shows a section A-A through the concrete body  2  depicted in  FIG. 1 . Evident are again the cover fold  6 , the center brim  7 , the water fold  8  as well as the two water courses  9  and  10 . 
     The concrete body  2  is comprised of a layer  17  of concrete, which is divided into three regions  18 ,  19 ,  27 . The region  19  is disposed above the region  18  and nearly completely overlaps the region  18 . The upper region  19  consequently forms a surface layer of concrete body  2 . Only the water fold  8  is not overlapped by surface layer  19 , that is region  19 . While regions  18 ,  19 ,  27  are comprised of the same green concrete mixture, however regions  18 ,  19 ,  27  differ in the mean grain size of the sand particles. In region  19  are thus only arranged sand particles whose grain size is below a certain limit value, while in regions  18  and  27  sand particles with a grain size above this limit value are present. In region  18  sand particles are arranged whose mean grain size is greater than the mean grain size of the sand particles of region  19  and  27 . 
     Region  27  has sand particles with a mean grain size which corresponds to that of the green concrete mixture used for the production of the concrete bodies. 
     In region  18 , consequently, the mean grain size of the sand particles is greatest while the mean grain size of the sand particles in region  19  is smallest. The sand in region  19  is therefore especially fine-grained. 
     Although not shown in  FIG. 2 , it is also conceivable for region  19  to be disposed on water fold  8  also. This is however not absolutely necessary since, as a rule, the water fold  8  in a roof structure is overlapped by a cover fold of a further concrete body. 
     On the upper side  1  as well as on the underside  11  of concrete body  2  additional layers can also be disposed. It is, for example, feasible to dispose on the upper side  1  of concrete body  2 , that is on region  19  or the surface layer, a colored layer. However, this is not shown in  FIG. 2 . 
       FIG. 3  depicts an enlarged segment of water course  9  of the concrete body  2  shown in  FIG. 2 . Readily evident is that the concrete layer  17  is divided into three regions  18 ,  19 ,  27 , namely into the upper region  19 
     forming the surface layer, the middle region  18  and the lower region  27 . In these regions  18 ,  19  and  27  sand particles are disposed whose mean grain size differs. In regions  18  and  27  sand particles with a grain size are present which do not occur in region  19 . Layer  17  with such a grain size distribution cannot be produced by simple smoothing, but rather, in the production of the concrete body  2  in region  19  forming the surface layer, a separation of the sand particles must have taken place as a function of the size of the sand particles. In the present invention this separation of the sand particles according to their size takes place through a profiling unit.   

       FIG. 4  depicts a side view of a segment of a plant  20  for the production of concrete bodies using the extrusion method. This segment of plant  20  comprises a working station  29  with an extrusion arrangement  30 , a surface working unit  31  and a belt conveyor  21  for conveying a continuous strand of lower molds  23  on which subsequently rest the band-shaped concrete body  2  of green concrete extruded onto the lower molds. The surface working unit  31  is downstream of the extrusion arrangement  30  and comprises a profiled profiling unit  26  and a levelling unit  28 . The levelling unit  28  comprises a non-profiled, that is a smooth, underside. The lower molds  23  to be filled with green concrete are first conducted by the belt conveyor  21  to the extrusion arrangement  30 . 
     This extrusion arrangement  30  includes a material box  32  supplied with green concrete  33 . This green concrete  33  has sand particles of various grain sizes. After the lower molds  23  have entered the material box  32 , green concrete  33  is applied onto these lower molds  23 . In the material box  32  are disposed a spiked shaft  24  and a profiled roller  25 . In a first step the spiked shaft  24  presses the green concrete  33  into the lower molds  23 . In a second step the green concrete is subsequently compacted through the profiled roller  25  into a band-shaped concrete body  2 , the body simultaneously receiving the desired profile. With the plant  20  shown here the concrete body  2  receives a cross sectional profile. 
     The band-shaped concrete body  2  is subsequently conducted to the surface working unit  31 , the concrete body  2  first passing the profiling unit  26 . This profiling unit  26  has in a lower region  59  a profile, preferably a
     comb-like profile. However, this profile is not visible in  FIG. 4 . By means of this profile of the profiling unit  26  onto the upper side  1  of the concrete body  2  a groove profile is applied by moving the concrete body  2  underneath the profiling unit  26  in the transport direction  22 . By means of the profile of the profiling unit  26  herein a separation of the sand particles according to their particle size takes place. Through this separation of the sand particles large sand particles are displaced inwardly out of the surface region of concrete body  2  while fine sand particles can pass the profile of the profiling unit  26  and thus remain in the surface region of concrete body  2 , that is in elevations of the groove profile. The fine sand particles herein have a mean particle size which is less than the mean particle size of the large sand particles.   

     When passing the profiling unit  26 , consequently, on the surface  1  of concrete body  2 , elevations of the groove profile are formed which are comprised of a very fine concrete. Simultaneously, air inclusions in the concrete can escape. After the groove profile has been applied on the concrete body  2  by means of the profiling unit  26 , the concrete body  2  is moved in the direction toward a levelling unit  28 . This levelling unit  28  serves for obliterating the groove profile applied on the concrete body  2 . The concrete body  2  is herein moved underneath the levelling unit  28  in the transport direction  22 , wherein the levelling unit  28  levels the upper side  1  of the concrete body  2 . This levelling takes place by squashing the elevations of the groove profile whereby the very fine-grained concrete of the elevations of the groove profile is uniformly distributed on the surface region of concrete body  2  and the upper region  19  is developed which forms the surface layer of concrete body  2  depicted in  FIGS. 2 and 3 . The upper region  19  can also be referred to as the surface layer  19 . After the groove profile of the surface  1  of concrete body  2  has been levelled, the band-shaped concrete body  2  is conducted in the transport direction  22  to a cutting station  34  depicted only schematically in  FIG. 4 . In this cutting station  34  the band-shaped concrete body  2  is cut into individual roof tiles by means of a cutting tool  35  movable reversingly to transport (cf. double arrow  36 ) and perpendicularly (cf. double arrow  37 ) with respect to the concrete body  2 . Onto the upper side of the roof tiles subsequently a coloring agent layer can be applied. Since these roof tiles have very low surface roughness, only very small quantities of coloring agent needs to be applied. 
       FIG. 5  shows a perspective view of an underside  67  of the lower region  59  of the profiled profiling unit  26 . On this underside  67  of the profiling unit  26  is provided a comb-like profile  40 . This profile  40  is comprised of several webs  41  to  45  disposed next to one another, which are each spaced apart from one another by an interval distance b. The underside  67  of the profiling unit  26  has substantially the shape of a concrete body. Sections  68  to  71  of profile  40  are herein evident. Section  68  serves to provide a cover fold of a concrete body with a groove profile. Sections  69  to  71  serve to provide the two water courses of a concrete body with a groove profile. With section  70  a groove profile is applied onto a center brim. A section with which a water fold of a concrete body can also be provided with a groove profile is not provided in the profiling unit  26  depicted in  FIG. 5 . With the profiling unit  26  a water fold of a concrete body is therewith not provided with a profile. 
     Although not depicted in  FIG. 5 , the levelling unit  28  has the same form as the profiling unit  26 , wherein the underside of the levelling unit  28  is smooth, which means that on the underside of the levelling unit  28  no profile is provided. A section for levelling, that is for smoothing a water fold of a concrete body, is not provided in the levelling unit  28 , especially since on the water fold no groove profile is being disposed with the profiling unit  26 . 
       FIG. 6  shows a segment of the profiling unit  26  depicted in  FIG. 5 , which has the comb-like profile  40  on its underside  67 . This profile  40  comprises several webs  41  to  45  with rectangular structure. The webs  41  to  45  have herein a width a as well as a length c. The individual webs  41  to  45  are furthermore spaced apart from one another by the interval distance b. With respect to the dimensions a, b and c, the profile  40  can assume the following values: 0.5&lt;a&lt;3 mm, 0.5&lt;b&lt;3 mm and 1&lt;c&lt;4 mm. Especially preferred are herein ranges from 0.5&lt;a&lt;2 mm, 0.5&lt;b&lt;2 mm and 1&lt;c&lt;4 mm, in particular a=1 mm, b=1 mm and c=2 mm. 
     To shape the comb-like profile  40  such that it is dimensionally stable, the width a and the length c of the webs must have a balanced ratio with respect to each other. The ratio c/a is preferably in the range of 1.5 to 2, which means 1.5≦c/a≦2. 
     In contrast, via the distance b a limit value for the size-dependent separation of the sand particles is predetermined. If as the dimension b, for example, 1 mm is specified, coarse sand particles with a grain size &gt;1 mm are displaced from the surface region of the concrete body  2 , while the fine sand particles with a grain size &lt;1 mm remain in the surface region and thus collect in the elevations (see  FIG. 8 , reference numbers  61  to  65 ) of the groove profile such that a surface layer can be formed of the fine concrete. 
     The choice of sand utilized for the production of the green concrete depends on the distance b, for the grading curve must be selected such that more than 60% of the sand particles have a grain size that is less than b. Only if this is ensured is the profile  40  adequately filled with fine sand particles and an adequate material flow through the profile  40  is ensured. 
     In  FIG. 7  is depicted a variant of a profiled levelling unit  46  with a profile  47 . This profile  47  is also structured in the shape of a comb, wherein profile  47  has webs  48  to  52  developed minimally conically. Due to these conically developed webs  48  to  52  the risk of the profile  47  to become clogged with concrete is lower. 
     It is understood that diversely profiled levelling units can also be selected provided that with them the separation of the sand particles according to their grain size is possible. 
       FIG. 8  shows the production of a groove profile on the upper side  1  of the concrete body  2  by means of the profiling unit  26 . In  FIG. 8  only a segment of the concrete body  2  as well as of the profiling unit  26  is shown. Visible is also the concrete layer  17  with sand particles of various sizes. By moving the concrete body  2  underneath and past the profiling unit  26 , the upper side  1  is worked. Due to the defined distance b of webs  41  to  45  with respect to one another, only sand particles with a very specific diameter are moved through the comb-like profile  40 . Sand particles
     with a diameter greater than b, are not conducted through the profile  40 . Thereby in the intermediate spaces of the profiling unit  26  only sand particles accumulate whose grain size is less than b. In  FIG. 8  are also visible several elevations  61  to  65  which are arranged in the intermediate spaces of the comb-like profile  40 . In the elevations  61  to  65  are, consequently, only on average smaller sand particles than in the subjacent regions of layer  17 .   

       FIG. 9  shows the levelling by means of the levelling unit  28  of the groove profile applied on the upper side  1  of the concrete body  2 . In contrast to the profiling unit  26 , this levelling unit  28  does not have a profile on its underside  60 . With this levelling unit  28  the elevations  61  to  65  can be levelled, whereby the elevations  61  to  65  on the upper side  1  of the concrete body  2  can be pushed downwardly. Consequently, squashing of the elevations  61  to  65  takes place through the levelling unit  28 . The upper side  1  of the concrete body  2  is smoothed through this levelling, whereby the upper region  19  is formed which is disposed above the region  18  and forms the surface layer. In region  19  only the smaller sand particles and in region  18  the smaller as well as also the larger sand particles are arranged. Through the smoothing, that is through the levelling of the groove profile, the larger sand particles are moved out of region  19  into region  18  such that in region  18  now only sand particles are arranged whose mean grain size is greatest. Through the smoothing not only the elevations  61  to  65  are obliterated but simultaneously it is also prevented that air collects in region  19 . It is therefore also feasible to utilize very fine sand in the concrete mixture of the concrete body  2  since, through the profiling and the subsequent smoothing of the upper side  1  of the concrete body  2 , air inclusions in the concrete are excluded. 
     If the profile of the profiling unit  26  has, for example, the dimensions a=1 mm, b=1 mm and c=2 mm, a sand with the grading curve listed in the following Table can be utilized. 
     
       
         
           
               
               
               
             
               
                   
                   
               
               
                   
                 Grain Size Range [mm] 
                 Percentage by Weight [%] 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                   
                 0.00-0.19 
                 9.8 
               
               
                   
                 0.20-0.39 
                 37.4 
               
               
                   
                 0.40-0.59 
                 27.3 
               
               
                   
                 0.60-0.99 
                 12.3 
               
               
                   
                 1.00-1.29 
                 3.7 
               
               
                   
                 1.30-1.59 
                 2.7 
               
               
                   
                 1.60-1.99 
                 2.5 
               
               
                   
                 2.00-3.19 
                 3.3 
               
               
                   
                 3.20-4.00 
                 1.0 
               
               
                   
                   
               
            
           
         
       
     
     As the Table shows, only 13.2% of the sand particles have a diameter of more than 1 mm. 86.8% of the sand particles have a diameter less than b, e.g. the diameter is less than 1 mm. Sand particles with a grain size greater than 1 mm are displaced into region  18  through the profiling unit  26 , such that region  19  is free of sand particles having a grain size greater than 1 mm. In region  18  therewith more sand particles having a grain size greater than 1 mm are arranged than in region  27 . 
     The thickness D of region  19  depends on the geometry of the profiling unit  26 . The following relation applies herein: 
         D =( c*b )/( a+b ) 
     Of advantage in levelling the previously applied groove profile is that a grain size distribution is obtained in which the larger sand particles are not arranged on the upper side of the concrete body and that here only sand particles with a smaller diameter are arranged. The concrete body hereby obtains not only a very smooth surface but the levelling of the elevations also contributes to the pores on the surface being smaller than in conventional concrete bodies, that is in concrete bodies in which no smoothing of a previously applied groove profile takes place. The concrete bodies produced in this manner have therefore improved surface quality. 
       FIG. 10  shows the concrete body  2  according to  FIG. 2  after a groove profile  66  has been applied on its upper side  1  by means of the profiling unit  26  according to  FIG. 5 . Through the specific form of the profiling unit  26  the groove profile  66  is only disposed on the cover fold  6 , the center brim  7  as well as on the two water courses  9  and  10 . The water course  8 , in contrast, does not have a groove profile. Since the water course  8  is overlapped by a cover fold of a further concrete body, improvement of the surface quality of the water fold  8 , specifically with respect to appearance, is not of significance. 
     Formulated generally, the invention consequently relates to a method for the production of a concrete body  2  extruded from green concrete  33 , characterized by the following sequential steps:
     the concrete body  2  is moved to a profiling unit  26  which on its underside has at least partially a profile  40 ,  47 , the profile  40 ,  47  being structured such that with the profile  40 ,  47  sand particles in the concrete body  2  can be separated according to their particle size;   by means of the profile  40 ,  47  of the profiling unit  26  on the upper side  1  of the concrete body  2  a groove profile  66  is applied, wherein in the groove profile  66  sand particles with a mean particle size are arranged whose mean particle size is less than the mean particle size of the green concrete  33 ;   the concrete body  2  with the groove profile  66  is moved to a levelling unit  28 , with the levelling unit  28  having an underside developed such that with the underside of the levelling unit  28  the groove profile  66  of the concrete body  2  is levelled, whereby on the upper side  1  a surface layer  19  and a subjacent region  18  is formed, wherein in the surface layer  19  only those sand particles are arranged which before the levelling were arranged in the groove profile  66 .   

     The invention further relates to a plant for the production of a concrete body  2  with a flat upper side  1 , comprising a working station  29  with an extrusion arrangement  30  for extruding a concrete body  2  of green concrete  33  as well as a profiling unit  26 ,  46  downstream from the extrusion arrangement  30 , characterized in that
     the profiling unit  26 ,  46  on its underside is provided with a profile  40 ,  47  structured such that with the profile  40 ,  47  a groove profile  66  can be applied on the upper side  1  of the concrete body  2 , wherein in the groove profile  66  sand particles with a mean particle size are arranged whose mean particle size is less than the mean particle size of the green concrete  33 ;   a levelling unit  28  downstream from the profiling unit  26 ,  46  is provided which has an underside  60  for levelling the groove profile  66 , wherein the underside of the levelling unit  28  is developed such that after the levelling of the groove profile  66  the upper side  1  of the concrete body  2  has an upper region  19  as well as a subjacently disposed region  18 , wherein the upper region  19  forms a surface layer, and the surface layer includes only the sand particles of the elevations of the groove profile  66 .   

     Although the embodiment examples of the invention have been described above in detail, the invention is not limited to these embodiment examples. A person of skill in the art understands that the invention comprises diverse variants with which the same result is obtained as with the embodiment examples described here. It is therefore obvious for the person of skill in the art that with the embodiment examples described here the protective scope of the claims is not restricted and that there are further variants, modifications and alternatives which fall within the protective scope of the claims. 
     REFERENCE NUMBERS 
     
         
           1  Upper side 
           2  Concrete body 
           3  Head-end section 
           4  Central section 
           5  Foot-end section 
           6  Cover fold 
           7  Center brim 
           8  Water fold 
           9  Water course 
           10  Water course 
           11  Underside 
           12  Cover fold rib 
           13  Cover fold rib 
           14  Water fold rib 
           15  Water fold rib 
           16  Water fold rib 
           17  Layer 
           18  Region 
           19  Region 
           20  Plant 
           21  Belt conveyor 
           22  Transport direction 
           23  Lower molds 
           24  Spiked shaft 
           25  Roller 
           26  Profiling unit 
           27  Region 
           28  Levelling unit 
           29  Working station 
           30  Extrusion arrangement 
           31  Surface working unit 
           32  Material box 
           33  Green concrete 
           34  Cutting station 
           35  Cutting tool 
           36  Double arrow 
           37  Double arrow 
           40  Profile 
           41  Web 
           42  Web 
           43  Web 
           44  Web 
           45  Web 
           46  Profiling unit 
           47  Profile 
           48  Web 
           49  Web 
           50  Web 
           51  Web 
           52  Web 
           59  Lower region 
           60  Underside 
           61  Elevation 
           62  Elevation 
           63  Elevation 
           64  Elevation 
           65  Elevation 
           66  Groove profile 
           67  Underside 
           68  Section 
           69  Section 
           70  Section 
           71  Section