Abstract:
A method and apparatus for producing tubular molded products from molding material includes a mold casing and a mold core having a common longitudinal central axis which is vertically disposed. The mold casing and mold core are spaced from one another to define a molding space therebetween. A supply device supplies molding material from above the molding space into the molding space. Treatment apparatus is disposed at treatment zones on the mold core for treating the molding material in the molding space, the treatment including treating the molding material by shaking the molding material or treating the molding material by heating the molding material, or both. The mold casing has an axial length which is less than an axial length of the molded product, to be produced and apparatus is provided for lowering a lower end of the column of molding material in the molding space in a direction parallel to the central axis from an initial position to a lowered position which enables production of a molded product of a desired longitudinal length.

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to a method and an apparatus for producing pipes or similar tubular molded objects from polymer concrete. The invention furthermore relates to a polymer concrete socket pipe. 
     In practice, for the production of pipes from polymer concrete, molding equipment is used, which consists of a mold core and a mold casing, which together form the boundary of a molding space. The molding space of the molding equipment, the main axis of which is aligned vertically, is filled with a mineral casting composition by means of filling equipment and this mineral casting composition is subsequently shaken as a whole. Sometime after the end of the shaking process, the mineral casting composition, which is at ambient temperature, commences to cure. After the curing process is largely concluded, the molding equipment casing is removed from the molded object. Since the pipe shrinks as it cures and, during the slow course of the curing process, the casing cannot be removed from the pipe before considerable shrinkage occurs, a sleeve-like compensating body, which then lines the finished pipe as a liner, must be placed on the mold core. 
     In the case of a method of an older proposal (P 43 39 118.4), the molded object is built up sectionwise along its central axis by filling consecutive longitudinal sections of the molding space of the molding equipment with mineral casting composition and shaking the mineral casting composition in the filling region and is cured sectionally phase-offset in the same direction. For this purpose, the molding equipment has a mold casing of superimposed, transposable casing segments, the segment parts of which in each case can be moved apart from an annular, closed operating position into nonoperative position and transposed in this position. The mold core is divided into axially limited sections, which form different treatment zones, it being possible to move the mold casing and mold core relative to one another in the axial direction during the production of a molded object. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to provide a method and an apparatus for producing molded objects, particularly a socket pipe, from polymer concrete. The method and apparatus are to enable tubular molded objects to be produced from polymer concrete with little operational and structural expense. 
     The invention enables pipes and tubular molded objects to be produced with a continuous or quasi continuous formation of the molded object in a molding space, which is stationary at least in the main part and which is traversed by the column of mineral casting composition. At the same time, the column of material is molded, solidified and cured. The structural expense of the molding equipment is exceedingly low, so that advantageous operating processes as well as simple retrofitting possibilities arise for the production of molded objects of different dimensions. 
     Further advantages and details of the invention arise out of the following description and the drawing, in which two examples of inventive molding equipment are shown diagrammatically. 
     FIG. 1 shows a side view of a first embodiment of the inventive molding equipment, partially in section, in a basic position before the start of the manufacturing process, 
     FIG. 2 shows a side view, half in section, similar to that of FIG. 1 to illustrate parts of an initial phase of the production of the molded body, 
     FIG. 3 shows a side view similar to that of FIG. 1 to illustrate the parts at the conclusion of the manufacturing process of a molded object, 
     FIG. 4 shows a partial, truncated, longitudinal section through a length region of the upper part of the mold casing, 
     FIG. 5 shows a section along the line V—V of FIG. 4, 
     FIG. 6 shows a partial, truncated, longitudinal section, similar to that of FIG. 4, through the lower end of the molding space, 
     FIG. 7 shows a diagrammatic plan view of the closing part with mold segments as inner mold for the socket part, 
     FIG. 8 shows a representation of a further embodiment of the inventive molding equipment, 
     FIG. 9 shows a sectional enlargement of FIG. 8 with a closing body in a starting position at the commencement of the manufacturing process, 
     FIG. 10 shows a representation similar to that of FIG. 8 to illustrate the molding equipment in a later phase of the operation, 
     FIG. 11 shows an enlarged sectional representation of the molding equipment of FIG. 8 to illustrate positions of the molding body in the process of formation while severing the film curtains, during the introduction of the intermediate supporting elements and after assumption of the support by these, 
     FIG. 12 shows a representation similar to that of FIG. 11 to illustrate positions of the molded object in the process of formation in consecutive phases of the continuous production process, 
     FIGS. 13 and 14 show enlarged sectional representations of the molding equipment of FIG. 8 for a more detailed diagrammatic representation of the interior tool of the film-severing equipment in two mutually orthogonal viewing directions, 
     FIGS. 15 and 16 are representations similar to those of FIGS. 13 and 14 to illustrate the exterior tool of the film-severing equipment and its support as well as the support of the intermediate supporting elements, 
     FIG. 17 shows a section along the line XVII—XVII of FIG. 15, 
     FIG. 18 shows a representation similar to that of FIG. 12 to illustrate the position of a finished molded object directly before it is discharged from the molding equipment, 
     FIG. 19 shows a diagrammatic plan view of discharging equipment for finished molded bodies, and 
     FIGS. 20 to  22  show truncated cross-sectional representations of socket pipes in a two-part construction. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The apparatus, shown in FIGS. 1 to  7 , is intended for the production of socket pipes M and comprises, in particular, molding equipment  1  with a vertical, longitudinal central axis  2 , which equipment has a mold core  3  and a mold casing  4 , as well as filling equipment,  5  for supplying a mineral casting composition into a molding space  6 , formed between the mold core  3  and the mold casing  4 . 
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In the vertical direction, the mold casing  4  comprises a stationary part  7 , the inner wall  8  of which forms the outside boundary of the molding space  6  and preferably is constructed cylindrically. For maintenance purposes, it may be possible to divide or dismantle part  7 . Under operating conditions, however, part  7  forms a closed structural unit. The axial length of part  7  corresponds to a fraction of the pipe to be produced and may, for example, have the dimensions of 120 cm. 
     In the case of the example shown, part  7  forms the upper part of the mold casing  4  which, in a plane running perpendicularly to the longitudinal central axis  2 , is divided into two parts  7 ,  9 , of which the lower part  9  forms the boundary of the molding space  6  in the region of the socket part of a socket pipe M that is to be produced and, in the axial length, may be limited essentially to the axial length of the socket region. In its axially extending plane, the lower part  9  is divided into two half parts  10 ,  11 , which can be moved by means of driving mechanisms  10   a ,  11   a  along diagrammatically indicated guides  12 ,  13  in opposite directions, horizontally, from a closed operating position (FIGS. 2 and 3) into an opened demolding position (FIG.  1 ). 
     For closing off the molding space  6  at the bottom, a closing part  14  is provided, which can be lowered from an upper starting position (FIGS. 1 and 2) into a lower end position by a distance, which corresponds essentially to the nominal length of a molded object to be produced, which in this case is a socket pipe M. In particular, the closing part  14  comprises a ring-shaped supporting panel  15  and an inner mold  16  of the socket part, which is supported on the supporting panel  15 . 
     The lower part  9  of the mold casing  4  is supported on the supporting panel  15  of the closing part  14  and can be lowered together with the closing part  14  from the upper starting position of the latter into the lower end position of the latter, as is illustrated in FIG.  3 . In the lower end position of the closing part  14 , the half parts  10 ,  11  of the lower part  9  of the mold casing  4  can be transferred to the final demolding position, as is indicated by the arrows  17 ,  18 , and can be raised in this demolding position together with the closing part  14  into an intermediate position (FIG. 1) at the level of their operating position immediately below the upper part  7 , as indicated by arrows  19 ,  20 . From the intermediate position, the half parts  10 ,  11  can then be moved horizontally in opposite directions inwards into the operating position (FIG. 2) (Arrows  21 ,  22 ). For this purpose, the closing part  14  is supported on a lifting table  23 , which can be shifted along the vertical guides  24 , which can be constructed as threaded spindles and may be driven by means of driving mechanisms indicated diagrammatically at  25 . 
     Preferably, the parts  3 ,  4 ,  14  of the molding equipment  1  are mounted so that they can be swiveled as a whole alternately about the longitudinal central axis  2 . The swiveling angle may, for example, amount to about 300°. The outlet  5   a  of the filling equipment  5  is stationary and discharges into the region above the molding space  6 , which is open towards the top. This ensures that the molding space  6  is filled uniformly with the mineral casting composition. 
     Instead of this, it is, however, also conceivable to move the filling equipment  5  or its outlet  5   a , when the latter is formed, for example, by a hose, on a circular path in such a manner, that the outlet  5   a  circles above the molding space  6  about the longitudinal central axis  2  with a sector angle of about 300°. 
     To insure pivotability about the longitudinal central axis  2 , the upper part  7  of the mold casing  4  is supported over a mounting device  5   a  on a stationary, annular supporting table  27  and the closing part  14  of the mold casing with its supporting panel  15  is supported over a mounting device  28  on the lifting table  23 , so that the parts  7  or  9 ,  14  can be swiveled basically independently about the longitudinal, central axis  2 . Diagrammatically shown driving mechanisms  3   a ,  7   a ,  9   a , however, ensure that the parts  3 ,  7 ,  9  and  14  experience synchronous, alternating swiveling. To ensure the swiveling motion of the mold core  3 , the latter is supported at a central guiding element  29 , which is carried in the region of its upper end by a mounting device  30 . 
     Groups of supply rolls  31 ,  32  for film strips, which form the mold curtains  33 ,  34  lining the molding space  6  on the inside and the outside, are assigned to the mold core  3  and the upper part  7  of the mold casing  4 . The supply rolls  31 , assigned to the mold core  3 , are mounted on a supporting frame  35 , which is supported at a central guiding element  29  for the mold core  3  and participates accordingly in the alternating swiveling motion of the central guiding element  29  with the mold core  3 . The supply rolls  32 , assigned to the upper part  7  of the mold casing  4 , are mounted at a supporting frame  36 , which is supported at an upper part  7 , and participate accordingly in the alternating swiveling motion of the upper part  7  of the mold casing  4 . 
     The film strips, which run off from the supply rolls and preferably consist of polyester, may, for example, have a width of 10 cm and overlap in the film curtain  33  or  34  by, for example, about 10 mm. After onset of the mutual overlapping and before they enter the molding space  6 , the strips can be connected with one another at the edges, for example by gluing or sealing the edges. Instead of this, it is also possible to form the film curtains in each case from only two film strips or to use a tubular film and to take this tubular film from a storage bin containing tubular film folded in zigzag fashion. 
     Instead of lining the inside and the outside of the molding space  6  with a film or also in addition to such lining, it is possible to use a lubricant, which can emerge, for example, from delivery openings in the upper edge region of the inner wall of the upper part  7  and from delivery openings in the mold core  3  in a region close to the upper end of the molding space  6  and can coat the axial boundary surface of the molding space  6  with a film in such a manner, that the mineral material composition or the film pass by the boundary surfaces without direct contact. The lubricant can be one which, upon complete curing of the mineral casting composition, becomes a permanent component of the surface or fulfills strictly a lubricating function, when it is used in addition to a film. 
     In order to fix film curtains  33  and  34  during and between operational processes, annular suction adhesion regions  37 ,  38 ,  39  and  40  are provided in each case in the region of the lower edge of the inner wall  8  of the upper part  7  of the mold core  3 , of the upper edge of the inner wall of the lower part  9  of the mold core  3 , of the lower edge of the outer wall of the mold core  3  and of the rear wall of the inner mold  16  of the socket part of the closing part  14  facing the mold core  3 . The suction adhesion regions  37 ,  38 ,  39 ,  40  are formed by chambers  41 , which can be connected to a vacuum source and evacuated and are connected over suction openings  42  with the molding space  6 . 
     For severing the film curtains  33 ,  34  in a plane, which extends at a specified distance below the underside of the upper part  7  of the mold casing  4  and above the upper end of the finished molded object M transversely to the longitudinal central axis  2 , film-severing equipment (FIG. 3) is provided, which is indicated diagrammatically at  43  and can have a heatable severing wire, for example, as a severing element. 
     At its surfaces facing the molding space  6 , the inner mold  16  of the socket part of the closing part  14  can have a coating  44 , which yields under shrinkage pressure. This coating  44  enables the socket part of the socket pipe M to shrink during the presence of the part  16 . In addition to or instead of this, the inner mold  16  of the annular socket part may also be formed by a number of mold segments  45 , which are supported from their operating position radially inwards on the supporting panel  15  and can shift radially inwards, for example, against the action of a spring, if they are acted upon by the shrinkage pressure of the curing mineral material composition. In the supporting panel  15 , preferably driving mechanisms  16   a  are provided, by means of which the mold segments  45  of the inner mold  16  of the socket part can be moved between their operating position and an inwardly shifted demolding position, in which they are disengaged from the socket part of the socket pipe M, even when the latter shrinks. In order to offer an essentially closed boundary surface in the operating position and nevertheless to make possible the shifting from the operating position into the demolding position, relatively wide mold parting lines, in which an elastically compressible sealing element  45 ′ is provided, may be provided between the mold segments  45 , of which four are preferably provided. 
     The mold casing  4  can be heated over the whole height of the molding space  6  and, for this purpose, has heating means, which carry out the heating for example, by electrical means, in the walls of its upper and its lower parts  7 ,  9 . The heating can also be accomplished by a liquid or gaseous heating medium, which can be passed through heating ducts  46  in the upper and lower parts  7 ,  9  of the mold casing  4 . Appropriate heating means are also provided in the mold core  3 , namely in the region of a heating zone, which can extend practically over the height of the whole of the molding space  6 , as in the case of the mold casing  4 . Instead of this, it is also possible to provide a heating zone in the mold core  3 , which heating zone, in the operating position of the mold core, commences only at a distance below the upper end of the molding space  6  and extends as far as the lower end of the molding space  6 . 
     The mold casing  4  and/or the mold core  3  can have a heating zone  48 , which comprises microwave generators  47  as heat generators. The microwave heating zone  48  preferably is assigned to the mold casing  4  in the region of its upper part  7  and, for the heating, is provided additionally with heating means of the previously mentioned type although, in principle, heating exclusively by electromagnetic microwaves is also conceivable. 
     The mold core  3  has a shaking zone which, at the start of a manufacturing process, initially consolidates the mineral casting composition in the lower part of the molding space adjoining the lower end of the molding space  6  and then, as the level of the mineral casting composition in the molding space  6  rises, is intended to consolidate the mineral casting composition also in upwardly adjoining regions of the molding space and, finally, in that region of the molding space  6 , which adjoins the upper end of the molding space  6 . This can be brought about in that, in the mold core  3 , an axially limited shaking zone is formed, which is level with the lower region of the molding space  6  at the start of the manufacturing process and then, by pulling up the mold core  3 , is moved into an upper end position, which adjoins the upper end of the molding space  6  and in which it then remains stationary during the further manufacturing process. 
     Instead of that, the shaking zone can also extend over the whole height of the molding space  6  and be formed by axially limited partial shaking zones  50 ,  51 ,  52 , which are disposed one above the other and have vibrators  55 , which can be switched on and off independently of one another. The partial shaking zones  50 ,  51 ,  52  can, at the same time, each embrace a separate mold core pipe section which, while retaining a joint  54 , bridged by an elastic seal, is supported independently at an internal support of the mold core  3  and, in each case, carries its own vibrator  55 . The mold core  3  shown has three partial shaking zones  50 ,  51 ,  52 , which are separated by joints  54  from one another and from the parts of the mold core  3  adjoining above and below. Accordingly, first the partial shaking zone  50 , then the partial shaking zone  51  and finally the partial shaking zone  52  can be activated by switching on the vibrator and the active region of the shaking zones can thus be extended in steps from the bottom to the top over the full height of the molding space  6 . If the vibrators in the partial shaking zone  50  are switched off after the vibrators in the partial shaking zone  51  are switched on and, if the vibrators in the partial shaking zone  51  are switched off after the vibrators in the partial shaking zone  52  are switched on, then the active region of the shaking zone can also be shifted axially from the bottom to the top. 
     For producing a film object in the form of a socket pipe M, the half parts  10 ,  11  of the lower part  9  of the mold casing  4 , starting out from the position of the parts in FIG. 1, are initially transferred by a movement in the direction of the arrows  21 ,  22  into their operating position, in which the suction adhesion region  38  comes to lie opposite to the lower end of the film curtain  34  and fixes this by applying a vacuum. 
     After that, the mold core  3  is lowered into a position, in which its suction adhesion region  39  lies opposite and is aligned with the suction adhesion region  40  of the closing part  14 . In this position of the parts, the suction adhesion region  39  is deactivated and the suction adhesion region  40  activated, so that the film curtain  33  is loosened from the lower end of the mold core  3  and fixed to the closing part  14 . 
     After this preparation of the molding equipment for the production operation, the parts of the equipment are in the position of FIG. 2, in which the molding equipment  1  is then caused to swivel alternately about the longitudinal central axis  2 . With or after the onset of this alternating oscillatory movement, the filling equipment  5  is set in operation and mineral casting composition is filled over the outlet  26  into the molding space  6 . At this point in time, the heating zones of the mold casing  4  and of the mold core  3  are operating with the result that the boundary walls of the molding space  6  have their specified operating temperature, for example, of the order of 70-100°. 
     As the filling of the molding space  6  commences, the lowest partial shaking zone  50  of the mold core  3  is started up and the partial shaking zones  51  and  52  are switched on as soon as the level in each case reaches their lower end. With the switching on of the partial shaking zone  51 , the shaking in the partial shaking zone  50  can be switched off and, with the switching on of the partial shaking zone  52 , the shaking in the partial shaking zone  51  can also be switched off, so that shaking takes place now only in the region of the partial shaking zone  52 . 
     When the nominal upper level in the molding space  6  is reached, the further supply of mineral casting composition, to begin with, is interrupted until, as a result of the heating of the mineral casting composition, the curing process commences in this composition in the region of the lower part  9  and in the lower region of the upper part  7  and leads to a first solidification of the mineral casting composition, which makes it possible to commence now with the lowering of the closing part  14  along with the lower part  9  along the guides  24 . With the onset of the lowering process, the column of material in the molding space  6  as a whole commences a downward motion, which is produced by gravity and optionally supported by the pulling action on the film curtains  33 ,  34  and, with the start of which, the supplying of mineral casting composition by the filling equipment  5  is resumed and metered in such a manner, that the level in the molding space  6  is maintained essentially constant at the scheduled height. As the lowering of the material column in the molding space  6  commences, the heating zone  48  additionally is activated in order to intensify the transfer of heat to the material column in motion and to ensure that, in the mineral casting composition continuously moving downwards in the molding space  6  between the upper part  7  and the mold core  3 , a curing process is initiated, which generates in the mineral casting composition, emerging from the upper part  7 , already such a strength that the necessary shape maintenance of the molded object M is assured during the further downwards motion. 
     In general, it is possible to control the shaking and heating while continuously filling the molding space and continuously lowering the column of material in such a manner, that the formation of the molded M object proceeds continually. It is, however, also conceivable to form the molded object M in steps. For example, at the start of the production process, the molding space  6  can be filled very rapidly up to a nominal height and the filling and shaking can be followed by a phase, in which the mineral material composition is merely heated. This can then be followed by a relatively rapid lowering process of the column of material with appropriate maintenance of the nominal state in the molding space  6 , until approximately the whole of the preconsolidated part of the column of material is moved out of the molding space in the upper part  7 . At this time, the further lowering motion of the parts  9 ,  14  is interrupted until the column of material, which is in the molding space in the upper part  7  at this time, has acquired the preliminary solidification, required so that it can be discharged from the molding space  6 , as a result of the curing process that has been initiated. Subsequently, in a rapid lowering motion, this part of the column of material is once again essentially discharged from the molding space  6  which, while stopped, is filled with more material composition for the next discharging process, until the production of the molded object is concluded. 
     The question of moving the column of material continuously through the molding space  6  or moving the mineral material composition intermittently depends essentially on the formulation of the mineral casting composition and on the therefrom resulting temperature, at which the curing process is initiated, as well as on the pot life and the curing rate. Preferably, a mineral casting composition is used, which offers an initiating temperature, which is raised above ambient temperature and preferably falls in the range of about 50 to 90° and advantageously between 60 and 70° due to the addition of a curing agent, and which contains a curing accelerator, such as a cobalt accelerator, which shortens the curing process. 
     If, in the course of the production process conducted in the manner described above, the column of material has reached a length corresponding to the nominal length of the pipe that is to be produced, the further supply of mineral material composition is terminated by switching off the filling equipment  5  and the handling process is continued until the parts essentially have reached the position illustrated in FIG. 3, in which the closing part  14  and the lower part  9  are in their final, lower position. At the same time, the upper end of the socket pipe M produced is at a specified distance below the upper part  7 . 
     For demolding the socket pipe M, the mold core  3  is first moved upwards some distance, until the lower end of the mold core  3  is slightly above the severing plane, which is defined by the equipment  43  and in which the equipment  43  subsequently severs the film curtains  33 ,  34 . Previously, the film curtains  33 ,  34  were fixed by activating the suction adhesion region  39  of the mold core  3  and the suction adhesion region  37  of the upper part  7 . Thereupon, the half parts  10 ,  11  are moved apart horizontally as indicated by the arrows  17 ,  18  along the guides  12 ,  13  into the demolding position. At the same time, the mold segments of the inner mold  16  of the socket part are shifted inwards into their demolding position by means of the driving mechanism  45 , so that the socket pipe M, which is still surrounded on the outside and inside by film, can be removed by means of hoisting equipment and taken away for further treatments. Subsequently, the lifting table  23  is shifted upward along the guides  24  in the direction of the arrows  19 ,  20 , until the position of FIG. 1 is reached, starting out from which a new production process can now be commenced. 
     When pipes are produced with a cross section, which remains the same over the whole length, it is possible to do without the lower part  9  and the closing part  14  can consist essentially of the supporting panel  15  alone. The process can be controlled automatically, programmed on the basis of measurement data, such as the outside temperature of the column of material at a level equal to that of the lower end of the upper part  7 , the weight or the volume of the mineral material composition supplied, the level of material in the molding space  6 , the position of the closing part on its way to the lower end position, etc. Depending on the length and diameter of the pipes to be produced and on the composition of the mineral casting composition, cycle times of the order of 2 to 4 minutes can be attained. 
     The second embodiment of inventive mold equipment, illustrated in FIGS. 8 to  19 , corresponds largely with that of FIGS. 1 to  7  and identical parts have been given the same reference numbers. Contrary to the mold equipment of FIGS. 1 to  7 , the second embodiment of FIGS. 8 to  19  has a mold casing  4 , which consists only of the stationary, closed upper part  7 . The lower part  9  is not required, since pipes with a constant cross section or with one or two spigots or ends of a similar nature are to be produced with the second embodiment, for which changes in shape lie within the cylindrical contour of the tubular body. 
     The closing part  14 ′ of the second embodiment has a basically different construction. Admittedly, it also encompasses the supporting panel  15 . Primarily, however, it comprises a separator  60 , which can be inserted from above into the molding space  6  between the mold casing  4  and the mold core  3  and forms the lower boundary of the molding space  6 . As can be seen, for example, in FIGS. 9 and 17, the separator  60  is constructed as an annular part, which molds at least one adjacent end  61  of a molded body R, which is to be formed, into a spigot. For this purpose, the separator  60  is provided with an external annular flange  62 , which extends upwards from the upper side  63  of the separator  60  at the outer periphery and, with that, parallel to the adjacent inner wall  8  of the mold casing  4 . In the drawing, the annular flange  62  is reproduced only diagrammatically. The exact conformation of its shape is determined by the exterior shape of the pipe end, which is to be formed. If molded bodies R are to be formed with two spigots, the separator  60  can be provided additionally with a ring shoulder (not shown), corresponding to ring shoulder  62  and extending downward. 
     The separator  60  is provided on the inside and outside with a peripheral indentation  64  or  65  for engagement by film severing elements, which will be dealt with in greater detail below. The separator  60  furthermore has holding pockets  66 , which are open to the outside and into which intermediate supporting elements  67 , which will be described in greater detail below and can be provided with a vertically aligned central slot  68 , can be introduced. As a result of the slots  68 , the intermediate supporting elements  67  can be introduced into two holding pockets  66  each and accommodate in their slot  68  a partition  69  between adjacent holding pockets  66 . 
     As can be inferred from FIG. 17, the separator  60  is divided in the vertical direction into several segments  70  (four in the Example shown), which make it possible to assemble the separator  60 , for example, with the help of feeding equipment, the details of which are not shown, in a region immediately above the filling opening of the molding space  6  by moving the segments  70  together and then introducing the assembled separator  60  into the molding space  6  from above. Due to the segmented construction, the separator  60  can be detached at the end of the formation of the molded object from the molded object R by pulling off the segment  70  radially. 
     Below the mold casing  4  and the mold core  3 , film-severing equipment  75  with an inner and an outer severing tool  76  and  77  respectively is provided and illustrated in some of the Figures of the drawing only by a line representing the severing plane. However, as shown particularly in FIGS. 13 to  16 , each severing tool  76 ,  77  is provided with a number of radially directed cutting knives  78 , which can be moved in each case by means of a diagrammatically illustrated pressure medium cylinder  79 , from the neutral position shown radially (outwards or inwards) into an operating position, in which they in each case reach through the cylindrical surface of the film curtains  33  and  34  and protrude into the indentations  64  and  65  respectively of a separator  60 , the horizontal central plane of which, when the film-severing equipment  75  is actuated, is level with the severing plane of the film-severing equipment  75 . 
     In the operating position of the cutting knives  78 , the severing tools  76 ,  77  can be swiveled alternatingly about their respective central axis, which coincides with the longitudinal central axis  2  of the molding equipment  1 . The swiveling angle is selected so that the cutting knives  78  together pass through an uninterrupted circular arc. 
     The inner severing tool  76  is fastened to the underside of the mold core  3  and rotatably supported in a bearing part  80  and can be swiveled alternatingly by means of a driving mechanism  81 . The outer severing tool  77  comprises an annular support  82 , which is guided between upper and lower guide rolls  83 ,  84  and can be swiveled alternately by means of a pressure medium driving mechanism  85 . 
     The guide rolls  83 ,  84  are supported on the upper side of an outer supporting ring  86 , which is suspended from the underside of the mold casing  4 . For this purpose, the outer supporting ring  86  is movably supported at the guides  87  parallel to the longitudinal central axis  2  of the mold equipment  1  and can be moved by means of a driving mechanism  88  between an upper end position and a lower end position. In the case of a particularly simple embodiment, the guides  87  are constructed as threaded spindles, which reach through counterthreads in the outer supporting ring  86  and can be driven uniformly to one another by means of synchronous motors  88 , so that the outer supporting ring  86  experiences a precisely parallel shift. 
     At its underside, the outer supporting ring  86  supports the intermediate holding elements  67 , which in each case can be moved by means of a pressure medium driving mechanism  89  from a neutral position radially inwards into engagement with the holding pockets  66  of a separator  60 . In this way, the intermediate holding elements  67 , of which, for example, four, distributed over the periphery are provided, can be moved up and down for purposes, which will still be discussed further below. 
     At its upper side, the supporting panel  15  carries fastening jaws  90 , which can be moved in each case by means of a pressure medium driving mechanism  91  from a neutral position radially inwards into engagement with the lower end of a molded body R supported on the supporting panel  15  or with the separator  60  surrounding this end, in order to secure the end of the molded body on the supporting panel  15 . 
     For discharging finished molded bodies R from the molding equipment  1 , discharging equipment  92 , which is located laterally next to the molding equipment  1  in the neutral position, is provided at a height between the supporting panel  15  in its lower end position and the outer supporting ring  86 . The discharging equipment  92  has two groups of suction grippers  93 ,  94 , which are disposed mutually above one another, in the initial gripping position lie diametrically opposite to one another and to the molded object R and can be moved by means of a pressure medium driving mechanism  95  from a neutral position radially inwards in opposite directions against the molded object R and can be acted upon with a vacuum by means of a pressure medium source, which is not shown. 
     The grippers  93 ,  94  are supported at a frame  96 , which can be moved horizontally and makes it possible to bring a finished molded body R, which has been taken hold of, from its position in the molding equipment  1  to a storage area, which can be formed, for example, by a further processing station, a refrigerated room or the like. The movement of the frame  96  can be brought about, for example, with the help of threaded spindles  97 , which can be driven by driving motors that are not shown. 
     For starting up the apparatus, the film curtains  33 ,  34  are suspended in a molding space  6  and in the molding space  6  and, at the same time, a tubular spacer  98 , which is supported on the supporting panel  15  and secured on this with the help of the fastening jaw  90 , is introduced from below between the film curtains  33 ,  34 . The separator is then introduced from above into the molding space  6  between the film curtains  33 ,  34  and placed on the upper end of the spacer  98 . 
     At the start of the process for producing a molded object R, the first separator  60  is in a position relatively closely beneath a specified upper nominal height for the mineral casting composition in the molding space  6 , so that, after the introduction of the mineral casting composition by means of the filling equipment  5  is commenced, the specified nominal height is soon reached. At the time at which the charging of the filling space  6  with mineral casting composition is commenced, the parts  3 ,  4  (including the parts connected with these) are in alternating swinging motion, so that the mineral casting composition is distributed rapidly and uniformly in the molding space  6 . Furthermore, at this time, the shaking zone  52  of the mold core  3 , adjoining the upper end of the molding space  6 , is also already in operation, so that, as soon as the filling of the mineral casting composition is commenced, this composition is shaken in the molding space  6 . 
     When the specified filling level is reached, the lifting table  23  is moved downward. This downward motion is coordinated by the filling equipment  5  with the mineral casting composition supplied in such a manner, that the nominal height is constantly maintained. Above the separator  60 , which is lowered with lifting table  23 , a column of material is accordingly built up progressively and preferably continuously in the molding space  6  and passes first through the shaking zone  52  and then through a downwardly adjoining heating zone, in which it is exposed to heating, preferably from inside as well as from outside. In the course of the heating, the curing process is initiated. As a result, in a region above the outlet plane of the molding space  6 , the molded body R, which is being formed, in each cases reaches a degree of curing, which provides the emerging end of the molded body with such a strength (for example, 20% to 25% of the final strength), that undesired shape changes are excluded. 
     As soon as the separator  60  reaches the region of action of the film-severing equipment  75 , a downward motion is imparted to the outer supporting ring  86 , which corresponds to the downward motion of the separator  60 , so that there is no relative axial motion between the separator  60  and the cutting knives  78  of the film-severing equipment  75  during the subsequent severing of the film curtains  33 ,  34 . As soon as the film severing process is concluded and the knives  78  have been returned to their neutral position, the outer supporting ring  86  returns to its upper end position, in which at this time the intermediate supporting elements  67 , which are still below the separator  60 , are located in one plane. As soon as the separator  60 , in the course of its steady downwards motion, reaches the region of action of the intermediate supporting elements  67 , the outer supporting ring  86  once again commences a synchronous downwards motion, so that the intermediate supporting elements  67  can be introduced into the holding pockets  66  of the separator  60 , without there being any relative axial movement between the parts. 
     As soon as the intermediate supporting elements  67  engage the separator  60 , they take over the supporting of the separator  60  and, with that, the supporting of the molded object R resting on it, insofar as this object has already been formed. This makes it possible to move the lifting table  23  and the supporting panel  15  resting on this table downward at an increased rate with the consequence that the spacer  98  is freed from supporting contact with the underside of the separator  60  and that the discharging equipment  92  can commence its activity as soon as the lifting table  23  has reached its lower end position. For taking out the molded object R, the lifting table  23  with the spacer  98  is first of all lifted once again by a short distance, the suction grippers  93 ,  94  are brought into engagement and the fastening jaws  90  are loosened, after which the lifting table  23  once again is moved down into its lower end position. By these means, the spacer  98  is held by the suction grippers  93 ,  94  so that it can move freely and can be moved out of the molding equipment  1  with the help of the frame  96 . 
     As soon as the spacer  98  is removed, the lifting table  23  is moved up once again to contact the separator  60 . As soon as this contact is made, the upwards movement is converted into downward motion, which is synchronous with the intermediate supporting elements and for which the supporting panel  15  once again can assume the function of supporting the separator  60  and the molded body R above the separator  60 . As soon as the fastening jaws  90  have secured the lower end of the molded object R and of the separator  60  on the supporting panel  15 , the intermediate supporting elements  67  are moved back into their neutral position, whereupon the outer supporting ring  86  is returned into its upper end position. 
     As soon as the molded body R, which is being formed, has reached its specified length, which can be determined by measuring the path, determining the weight or in some other suitable manner (photoelectric barrier), the supply of mineral material composition is switched off and a separator  60  is deposited on the upper end of the column of material. After being introduced into the molding space  6 , this separator  60  settles under gravity on the upper end of the column of material or can also be placed with the help of pressure elements on the upper end of the column of material. As soon as the new separator  60  is resting on the upper end of the column of material, the supply of mineral casting composition is continued once again and initially carried out on a greater scale, so that shortly, despite the further downward motion of the previously formed molded body R, the column of material of the molded object R, which is to be formed next, once again attains the specified nominal height in the molding space  6 . After that, the manufacturing process is continued in the manner already described; after the film curtains  33 ,  34  are severed and the finished molded object R, which has been removed from the molding space  6 , is detached from the separator  66  above this molded body R, the latter is removed from the molding equipment  1  with the help of the discharging equipment  92  as described previously with respect to the spacer  98 . The position of the molded body R, which is raised once again at the time, at which the molded body R is removed by the discharging equipment  92 , is illustrated in FIG. 18 by phantom lines. At the same time, FIG. 11 illustrates by a phantom line the upper end of the molded object R, moved by the accelerated lowering of the lifting table  23  out of contact with the separator  60  above. 
     The pipes, produced with the second embodiment of the molding equipment  1 , can be used as propulsion pipes or, if formed with spigots at both ends, can be assembled with the help of double sockets into a pipeline. They can, however, also be used as molded blanks for further conversion in a treatment station, in which the ends of the pipes are finished, for example, by machining. 
     Preferably and pursuant to the invention, molded objects, produced according to the inventive method and with the second embodiment of the molding equipment  1 , are used as the main tubular component for the formation of a socket pipe, which consists of this main part and a separately constructed socket part, which surrounds the end of the main part with a connecting region, both parts being connected without a joint in the region of mutually facing surfaces. 
     FIGS. 20 to  22  show different embodiments of such polymer concrete socket pipes, which are assembled pursuant to the invention, in truncated half sections. For examples, FIG. 20 shows a main part  100  in the region of an end, which is unchanged in cross section and engages a separately produced socket part  101 , which surrounds with a connecting region  102  the end of the main part  100 . At the same time, the socket part  101  has a peripheral ring land  103 , which protrudes radially inwards and the internal diameter of which is identical with the internal diameter of the main part  100 . The socket part  101  is dimensioned so that a gap region  104  remains between the mutually opposite surfaces of the main part  100  and of the socket part  101 . The gap region  104  is filled with a polymer casting composition as adhesive, which is identical or at least compatible with the polymer component of the polymer concrete and forms an intimate connection. 
     For the embodiment of the socket pipe of FIG. 21, the socket part  101 ′ is joined to the end of the main part  100  by casting, a solid, joint-free connection also being formed. To increase the strength of the joint, the socket end of the main part  100  can be provided at the outside with a recess  105  which, if necessary, can also be provided for the embodiment of the socket pipe of FIG.  20 . 
     FIG. 22 illustrates an embodiment, for which both ends are constructed as a type of spigot with a recess  105  and  106 . In the case of the example shown, the recess serves to accommodate a seal  107 . The socket part  101 ″ is shaped particularly simply and can be glued by means of a polymeric compound casting composition in the gap  104 ′ to the socket end of the main part  100 . For increasing the strength of the connection, the socket part  101 ″ can also be provided on the inside, in the connecting region  102 , with an appropriate recess, which may also be provided in the connecting region  102  of the embodiment of FIG. 20. A polymer concrete composition, which has a slump test value that permits a flow into the joint gap regions  104 ,  104 ′ can also be used as polymeric casting composition.