Abstract:
An apparatus for producing plastic containers includes: a forming machine for producing plastic preforms; a blow-moulding machine for blowing the preforms to obtain containers, provided with a blow-moulding carousel having a plurality of blow-moulding moulds that expand the preforms to obtain the containers; a thermal conditioning station interposed between the forming machine and the blow-moulding machine; a storage station, configured for receiving and containing preforms; a supplying system for feeding the thermal conditioning station with preforms contained in the storage station.

Description:
FIELD OF THE INVENTION 
     The invention relates to a method and apparatuses for forming plastics for producing preforms that are subsequently expanded to obtain containers intended to be filled with a product. 
     BACKGROUND OF THE INVENTION 
     Moulding machines are known that are arranged for forming plastics to obtain preforms. Such machines can be compression-moulding machines, or injection-moulding machines. 
     Blowing machines are further known that are supplied with preforms and blow the preforms to obtain containers. 
     Filling machines are also known that fill containers with a product. 
     An apparatus is further known comprising a moulding machine for compression-moulding plastics to obtain preforms, a thermal conditioning station for the preforms, arranged downstream of the moulding machine, and a blowing machine arranged downstream of the thermal conditioning station and suitable for blowing the preforms so as to obtain containers therefrom. 
     The preforms are first compression-moulded, and subsequently removed from the moulding machine to be transferred to the thermal conditioning station, where they are heated to a temperature that is suitable for the blow-moulding step. During the advancing from the moulding machine to the thermal conditioning station, the preforms are arranged sequentially one after the other and move along a preset advance path. 
     The preforms, after being compression-moulded and before they advance to the thermal conditioning station, require a cooling step that is suitable for stabilising the shape thereof and for avoiding crystallisation phenomena that compromise the transparency of a bottle that is subsequently obtained from the preform and alter the mechanical features thereof. 
     The duration of the cooling step depends on the type and/or on the geometry of the preforms. Thus, a given period of time required for the cooling step corresponds to a given geometry and/or type of preform. For given types or geometries of preforms it is necessary to slow the moulding machine so as to support the preforms for longer, thus enabling suitable cooling. This entails an undesired reduction in productivity in all those cases in which it is not possible to modify cooling efficacy. 
     The preforms, before being positioned on the blowing machine, have to be suitably heated, and for this purpose remain in the thermal conditioning station for a further set period of time that is a function of the geometry and/or of the type of preforms thereof. 
     A drawback of the aforesaid apparatus is that it has productivity that is limited by the time required for the preforms to be thermally conditioned. In particular, the productivity depends on the period of time that the preforms, arranged in sequence one after another along the advance path, require for the cooling step that is subsequent to compression-moulding. 
     In other words, the operation of the moulding machine located upstream and of the blowing machine located downstream depends on, and is constrained by, the period of time required for cooling the preforms that have just been moulded, this period of time depending on the type/geometry of the preform. 
     SUMMARY OF THE INVENTION 
     An object of the invention is to obtain an apparatus provided with a machine for producing preforms and with a machine for blowing such preforms to obtain containers that are operationally connected together in a flexible manner. 
     A further object of the invention is to obtain a method that enables a product to be packaged inside a container in a hygienic manner. 
     Another object is to obtain an apparatus for producing containers and for packaging a product in such containers immediately after such containers have been produced, in which the containers have not been damaged between the producing step and the filling step. 
     Another object is to obtain an apparatus for producing containers and for packaging a product in such containers that is provided with great efficiency. 
     A still further object is to obtain an apparatus for producing containers and for filling such containers with a product that is very compact. 
     In a first aspect of the invention, an apparatus is provided comprising a first operating machine arranged for processing objects, a second operating machine positioned downstream of said first operating machine and arranged for further processing said objects, an accumulating arrangement interposed between said first operating machine and said second operating machine and arranged for receiving said objects and a command and control arrangement arranged for detecting a parameter indicating the quantity of said objects contained in said accumulating arrangement and regulating the operation of said second operating machine on the basis of said parameter. 
     In one embodiment, the first operating machine is a compression-moulding machine arranged for forming plastics to obtain preforms and the second operating machine is a blow-moulding machine arranged for blowing the preforms to obtain containers. 
     Owing to this aspect of the invention, it is possible to obtain a very flexible apparatus. The compression-moulding machine and the blow-moulding machine have distinct driving devices. The speed of the blow-moulding machine is, within a certain limit, independent of the speed of the compression-moulding machine and can be varied according to the number of preforms contained inside the accumulating arrangement. Further, stopping the compression-moulding machine does not necessary entail stopping the blow-moulding machine, and vice versa. 
     In a second aspect of the invention an apparatus is provided comprising a compression-moulding machine, suitable for compression-moulding plastics to obtain preforms, a blow-moulding machine, suitable for blowing said preforms to obtain containers, a thermal conditioning station for said preforms, interposed between said compression-moulding machine and said blow-moulding machine, a moving arrangement for moving said preforms to an intermediate zone between said compression-moulding machine and said thermal conditioning station, wherein said moving arrangement is configured so as to advance said preforms along advance paths of variable length to vary the dwelling time of said preforms in said intermediate zone. 
     In a third aspect of the invention there is provided a method comprising compression-moulding plastics to obtain preforms in a first operating zone, blow-moulding said preforms to obtain containers in a second operating zone, thermally conditioning said preforms in a third operating zone interposed between said first zone and said second zone, moving said preforms to an intermediate zone interposed between said first operating zone to said second operating zone, wherein said moving comprises advancing said preforms along advance paths of variable length to vary the dwelling time of said preforms in said intermediate zone. 
     Owing to these aspects of the invention, it is possible to produce containers with high levels of efficiency and productivity. 
     In a fourth aspect of the invention a method is provided, comprising dispensing plastics in pasty state, during said dispensing said plastics having a dispensing temperature, compression-moulding said plastics to obtain a preform, blowing said preform to obtain a container, during said blowing said plastics having a blowing temperature, filling said container with a product, during said filling said plastics having a filling temperature, in which said dispensing temperature is greater than said blowing temperature and said blowing temperature is greater than said filling temperature. 
     Owing to this aspect of the invention, it is possible to package a product in a hygienically controlled manner. The dispensing temperature (i.e. the temperature of the plastics exiting a plasticising device, for example an extruder), is in fact greater than the temperature at which the destruction of possible microorganisms, in particular viruses and/or bacteria, is assured. 
     As a preform is obtained from the plastics at high temperature that is expanded within a short space of time to obtain a container that, in turn, is filled within a short space of time, all possibility of pollution is substantially eliminated. 
     In addition, the filling temperature is less than the blowing temperature by an amount that is such as to enable the shape of the container to be stabilised and not to be deformed during filling, in particular owing to the interaction with the product that has to be packaged. 
     The product, in particular if it comprises a fluid material, can contribute to cooling the plastics. This enables the container-manufacturing cycle to be shortened and simplified. 
     In one embodiment, after the compression-moulding step and before the blow-moulding step, the preform is cooled to a thermal treatment temperature that is less than the blowing temperature and the preform is subsequently heated to the blowing temperature. 
     After the plastics have been subjected to compression-moulding, the plastics have a higher temperature at an internal zone of the walls that bound the body of the preform and a lower temperature at external zones of the walls that bound the body of the preform. This is because the external zones of the walls that bound the body of the preform have interacted with a forming mould in which a cooling arrangement is provided, for example, with conduits through which a cooling fluid circulates. In addition, the external zones of the walls that bound the body of the preform, after extraction of the preform from the forming mould, have been cooled by the air in the environment. The heating of the preforms from the thermal treatment temperature to the blowing temperature is obtained by giving heat to the preforms by means of a heating device positioned outside the latter. Consequently, the external zones of the walls that bound the body of the preform receive a quantity of heat that is greater than the quantity of heat received from the internal zone of the walls that bound the body of the preform. In this manner, the difference in temperature between the internal zones of the walls that bound the body of the preform and the external zone of the walls that bound the body of the preform is noticeably reduced, or is even substantially eliminated. This enables the subsequent step of blowing the preform to be improved, which is optimal if the temperature of the walls that bound the body of the preform is substantially uniform along the thickness of the walls thereof. 
     In a fifth aspect of the invention, an apparatus is provided, comprising a compression-moulding machine arranged for compression-moulding plastics to obtain preforms, a blow-moulding machine arranged for blowing said preforms to obtain containers, a moving arrangement arranged for removing said preforms from said compression-moulding machine and delivering said preforms to said blow-moulding machine, a filling machine arranged for filling said containers with a product and a transferring device arranged for transferring said containers from said blow-moulding machine to said filling machine, maintaining said containers spaced apart from one another. 
     Owing to this aspect of the invention, it is possible to obtain an apparatus in which the containers are not damaged during transfer from the blow-moulding machine to the filling machine. The containers, which owing to the high temperature of some parts thereof are rather delicate, could be deformed and/or damaged so as to have aesthetic defects if they were placed in mutual contact immediately after being removed from the blow-moulding machine. This does not occur in the apparatus according to the invention as the transferring device prevents the containers from interacting with one another. 
     In an embodiment, the transferring device maintains the containers at a set distance from one another. In other words, the transferring device removes the containers from the blow-moulding machine according to a preset removal step and delivers the containers to the filling machine according to a preset delivery step (the removal step and the delivery step being able to be the same as or different from one another). 
     The blow-moulding machine and the filling machine can thus operate synchronously, which enables a very efficient apparatus to be obtained. 
     In a sixth aspect of the invention, an apparatus is provided comprising a moulding machine provided with a movable supporting device that supports a mould arrangement comprising a compression-moulding arrangement arranged for compression-moulding plastics to obtain preforms and a blow-moulding arrangement arranged for blowing said preforms to obtain containers, said apparatus further comprising a filling machine arranged for filling said containers with a product and a moving arrangement arranged for removing said containers from said moulding machine and delivering said containers to said filling machine. 
     Owing to this aspect of the invention, it is possible to obtain a very compact apparatus for packaging a product. In fact, the preforms are formed and blown on the same moulding machine and the containers obtained by blowing the preforms are immediately filled in a filling machine positioned downstream of the moulding machine. 
     In an embodiment, the compression-moulding arrangement comprises a compression-moulding die cooperating with a punch for compression-moulding the plastics and the blow-moulding arrangement comprises a blow-moulding die cooperating with the aforesaid punch to blow the preforms to obtain the containers. In other words, the compression-moulding die and the blow-moulding die interact with the punch the one after another. Initially, the compression-moulding die and the punch interact to form a preform. Subsequently, the compression-moulding die moves away from the punch and the preform is maintained on the punch. Still subsequently, the blow-moulding die moves towards the punch and interacts with the punch to define a forming chamber inside which the preform is expanded. 
     In one embodiment, the mould arrangement comprises a plurality of moulds supported by the movable supporting device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention can be better understood and implemented with reference to the attached drawings, which illustrate some embodiments thereof by way of non-limiting example, in which: 
         FIG. 1  is a schematic layout of an apparatus for forming preforms made of plastics, expanding the preforms to obtain containers and filling the containers with a product; 
         FIG. 2  is a detail of  FIG. 1 ; 
         FIG. 3  is a graph that shows how the temperature of the plastics varies over time during the plastics dispensing step, during the preform compression-moulding step, during the preform expansion step to obtain a container and during the container-filling step; 
         FIG. 4  is a graph like that in  FIG. 3  that further shows how the temperature of the plastics varies over time during a thermal conditioning step of the preform, interposed between the preform forming step and the preform expansion step; 
         FIG. 5  is a schematic layout of a further embodiment of an apparatus for forming preforms made of plastics, expanding the preforms to obtain containers and filling the containers with a product; 
         FIG. 6  is a perspective view of a mould of the apparatus in  FIG. 5  arranged for compression-moulding a dose of plastics to obtain a preform and for expanding the preform to obtain a container; 
         FIGS. 7 to 10  are sections taken along a longitudinal plane of the mould in  FIG. 6  that show subsequent steps of a work cycle of the mould; 
         FIG. 11  is a perspective view that shows a moving carousel and a step-varying carousel of the apparatus in  FIG. 5 ; 
         FIGS. 12 to 17  are plan views that show the moving carousel and the step-varying carousel in  FIG. 11  in subsequent steps of an operating cycle; 
         FIG. 18  is a schematic and fragmentary layout of a still further embodiment of an apparatus for forming preforms made of plastics, expanding the preforms to obtain containers and filling the containers with a product; 
         FIG. 19  is a detail of  FIG. 18 ; 
         FIG. 20  is a schematic layout of a version of the apparatus shown in  FIG. 18 ; 
         FIG. 21  is a detail of  FIG. 20 ; 
         FIG. 22  is a detail of  FIG. 21 ; 
         FIG. 23  is a schematic layout of another embodiment of an apparatus for producing containers; 
         FIG. 24  shows a detail in  FIG. 23  in a first operating configuration; 
         FIG. 25  shows the same detail in  FIG. 24  in a second operating configuration; 
         FIG. 26  shows the same detail in  FIG. 24  in a third operating configuration; 
         FIG. 27  is a schematic layout of a further embodiment of the apparatus for producing containers; 
         FIG. 28  is a schematic layout of a still further embodiment of the apparatus for producing containers. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to  FIGS. 1 and 2 , there is shown an apparatus  1  comprising a plasticising device, for example an extruder  2 , arranged for dispensing plastics in a pasty state. With the extruder  2  a cutting device is associated, which is not shown, that divides the plastics into doses. 
     The apparatus  1  further comprises a compression-moulding carousel  3  provided with a plurality of compression-moulding moulds  4 —for example positioned at constant angular intervals on a peripheral zone of the compression-moulding carousel  3 —that compression-mould the doses to obtain preforms. Each compression-moulding mould  4  comprises a female half mould and a male half mould that are movable towards and away from one another, the female half mould being provided with a cavity arranged for receiving a dose and the male half mould being provided with a punch arranged for penetrating inside the cavity to shape the dose. 
     The apparatus  1  further comprises a moving carousel  5  interposed between the extruder  2  and the compression-moulding carousel  3 . The moving carousel  5  removes the doses from the extruder  2  and inserts the doses into the compression-moulding moulds  4 . The moving carousel  5  further removes the preforms from the compression-moulding moulds  4  and delivers the preforms to a first transfer carousel  6 . 
     The apparatus  1  further comprises a blow-moulding carousel  7  provided with a plurality of blow-moulding moulds  16 —for example positioned at constant angular intervals on a peripheral zone of the blow-moulding carousel  7 —that expand the preforms to obtain containers. 
     Between the compression-moulding carousel  3  and the blow-moulding carousel  7  a thermal conditioning device  17  can be interposed arranged for thermally conditioning the preforms to prepare the preforms for blowing. 
     The thermal conditioning device  17  may comprise a thermal conditioning carousel  8  and/or one or more thermal conditioning tunnels. 
     The preforms are introduced into the thermal conditioning device  17  by the first transfer carousel  6  and are removed from the thermal conditioning device by a second transfer carousel  9 . 
     The apparatus  1  further comprises a filling carousel  10  on which a filling device is provided that fills the containers with a product, this product being able to comprise a liquid material, a powder or granule material, a paste material and the like. The aforesaid product can be, for example, a food product or a cosmetic product. 
     The apparatus  1  further comprises a transferring device  11  that removes the containers from the blow-moulding carousel  7  and delivers the containers to the filling carousel  10 . 
     The transferring device  11  comprises a rotating body  70  that supports a plurality of handling elements  71 , each of which is arranged for removing, retaining and delivering a container. 
     Each handling element  71  comprises a gripping element  74 , for example shaped as a gripper and arranged for grasping a neck zone of the container. 
     Each handling element  71  comprises a first arm  72  rotatably supported by the rotating body  70  and a second arm  73  rotatably supported by the first arm  72 , the gripping element  74  being connected to the second arm  73 . 
     The transferring device  11  comprises a first driving arrangement, arranged for moving the first arm  72  with respect to the rotating body  70  and a second driving arrangement arranged for moving the second arm  73  with respect to the first arm  72 . 
     In one embodiment, the first driving arrangement comprises a first revolving element rotatably connected to the first arm  72  and engaging with a first cam arranged in a fixed position with respect to the rotating body  70  and the second driving arrangement comprises a second revolving element rotatably connected to the second arm  73  and engaging with a second cam arranged in a fixed position with respect to the rotating body  70 . 
     The handling elements  71  maintain the containers spaced apart from one another. This enables damage to the containers to be avoided even if they are removed from the blow-moulding carousel when the plastics from which they are formed are still at a high temperature, and consequently, the containers are easily deformable. 
     The handling elements  71  are conformed in such a manner as to maintain the containers at a set distance from one another. 
     The handling elements  71  thus remove the containers from the blow-moulding carousel  7  according to a preset removal step and deliver the containers to the filling carousel  10  according to a preset delivery step (the removal step and the delivery step being able to be the same as or different from one another). 
     The blow-moulding carousel  7  and the filling carousel  10 , can thus function in a synchronous manner, which enables the efficiency of the apparatus  1  to be optimised. 
     In one embodiment, rather than a single transferring device  11  a plurality of transferring devices arranged one after the other can be provided. 
     The blow-moulding carousel  7  is provided in a dry zone of the apparatus  1 , whilst the filling carousel  10  zone is provided in a wet zone of the apparatus  1 . Inside the wet zone sanitising treatments take place. 
     The transferring device  11 , or the plurality of transferring devices, enable the aforesaid dry zone to be separated and spaced apart from the aforesaid wet zone. The aforesaid wet zone is maintained in slight overpressure—for example with sanitised air—with respect to the aforesaid dry zone. 
     The transferring device  11 , or the plurality of transferring devices, by retaining the containers on board for a certain period of time, ensure that the containers are suitably cooled before filling. For this purpose, the transferring device  11 , or the plurality of transferring devices, may comprise nozzles that direct jets of cooling fluid to the containers, in particular to a bottom zone of the containers, whilst the containers are supported and moved by the handling elements  71 . The apparatus  1  further comprises a capping carousel  12  provided with a capping device arranged for applying caps to the containers filled with the product. 
     The apparatus  1  further comprises a labelling carousel  13  provided with an applicating device arranged for applying labels to the containers filled with the product. 
     The apparatus  1  is further provided with a third transfer carousel  14  arranged for removing the containers from the filling carousel  10  and delivering the containers to the capping carousel  12 . 
     The apparatus  1  is further provided with a fourth transfer carousel  15  arranged for removing the containers from the capping carousel  12  and delivering the containers to the labelling carousel  13 . 
     According to one operating mode, the preforms, rather than being blown immediately after compression-moulding, can be removed from the apparatus  1 —for example at the second transfer carousel  9 —by a bypass device. In this case, the preforms, in the thermal conditioning device, are subjected to cooling that stabilises the shape thereof. After cooling, the preforms can be stored inside a container and moved without suffering damage or deformation. 
     The blow-moulding carousel  7  can be supplied, instead of with preforms coming directly from the compression-moulding carousel  3 , with cold preforms, for example made previously by the compression-moulding carousel  3 —and subsequently cooled—or manufactured by a different forming device. In this case, the preforms can be introduced inside the thermal conditioning device  17 , which heats the preforms in such a manner as to prepare the preforms for subsequent blowing. This operating mode can be applied for particular types of containers—and thus of preforms—that have to be produced in a limited number of examples. 
     Similarly, according to a further operating mode, the containers, rather than being filled immediately after blowing, can be removed from the apparatus  1 —for example at the transferring device  11 —by a further bypass device. 
     The filling carousel  10  can be supplied, rather than with containers coming directly from the blow-moulding carousel  7 , with containers manufactured previously. 
     As shown in  FIG. 3 , the dispensing temperature T 1 , i.e. the temperature of the plastics when they are dispensed by the plasticising device, is greater than the blowing temperature T 2 , i.e. than the temperature of the plastics when the preforms are expanded to obtain the containers. The blowing temperature T 2  is in turn greater than the filling temperature T 3 , i.e. than the temperature of the plastics when the containers are filled with the product. 
     This enables the product to be packaged in the containers in an hygienic manner. The dispensing temperature T 1  is in fact sufficiently high to ensure the elimination of the microorganisms. As the plastics extruded at high temperature are immediately compression-moulded to obtain the preforms, the preforms are immediately expanded to obtain the containers and the containers are immediately filled, the preforms are not contaminated before blowing and the containers are not contaminated before filling. 
     If the product is colder than the container intended to receive the product, the product contributes to cooling the plastics to the filling temperature T 3 . This enables the manufacturing cycle of the container to be decreased and the cooling modes to be simplified. 
     As shown in  FIG. 4 , the preforms can be cooled to a thermal treatment temperature T 4  that is less than the blowing temperature T 2  and be subsequently heated to the blowing temperature T 2 . 
     The preforms, after being extracted from the compression-moulding moulds  4 , are provided with walls that bound the body of the preform provided with an internal zone having a greater temperature and with external zones having a lesser temperature. 
     Cooling the preforms to the thermal treatment temperature T 4  and subsequent heating to the blowing temperature T 2  enables the difference between the temperature of the aforesaid internal zone and the temperature of the aforesaid external zones to be reduced and possibly to be substantially eliminated. This effect is obtained because the preforms, after being cooled to the thermal treatment temperature T 4 , are heated with a heating device that acts by giving heat to the aforesaid external zones until the temperature of such external zones differs by little from, or substantially equals, the temperature of the aforesaid internal zone. 
     A substantially uniform temperature profile through the thickness of the walls that bound the body of the preforms constitutes a condition that enables the blowing or stretch-blowing of the preforms to be optimised. 
     Heating from the thermal treatment temperature T 4  to the blowing temperature T 2  occurs in a controlled manner, in particular enabling the heat to spread through the thickness of the preforms to prevent the aforesaid heat causing overheating of the external surface of the preforms with respect to the immediately underlying layer. 
     Cooling the preforms to the thermal treatment temperature T 4  and subsequent heating to the blowing temperature T 2  is conducted in the thermal conditioning device  17 . The thermal conditioning device  17  is provided with heating elements, for example with infrared heating elements. The heating elements can perform differentiated heating of the preforms, i.e. heat different zones of the preforms in a differentiated manner. In one operating mode, zones of the preforms having a greater thickness are heated more than zones of the preforms having a lesser thickness. In a further operating mode, zones of the preforms intended for being more deformed during expansion are heated more than zones intended for being less deformed during expansion. 
     The dispensing temperature T 1  can be greater than the blowing temperature T 2  by an amount comprised between 50 and 195° C. and in particular by an amount comprised between 65 and 175° C. 
     The blowing temperature T 2  can be greater than the filling temperature T 3  by an amount comprised between 30 and 130° C. and in particular by an amount comprised between 70 and 120° C. 
     The thermal treatment temperature T 4  can be less than blowing temperature T 2  by an amount comprised between 5 and 85° C. and in particular between 20 and 50° C. 
     It has been ascertained experimentally that the temperature differences indicated above enable good results to be obtained. 
     Experiments conducted have enabled optimal temperature ranges to be achieved. 
     The dispensing temperature T 1  can be comprised in the range between 190-295° C. 
     For polyethyleneterephthalate (PET) the dispensing temperature T 1  is in particular comprised in the range between 250-285° C. and more in particular in the range between 265-275° C. 
     For polypropylene (PP) the dispensing temperature T 1  is in particular comprised in the range between 190-230° C. and more in particular in the range between 200-210° C. 
     The blowing temperature T 2  can be comprised in the range between 90-140° C. 
     For polyethyleneterephthalate (PET) the blowing temperature T 2  is in particular comprised in the range between 90-115° C. and more in particular in the range between 100-105° C. 
     For polypropylene (PP) the blowing temperature T 2  is in particular comprised in the range between 125-140° C. and more in particular in the range between 130-135° C. 
     The filling temperature T 3  can be comprised in the range between 10-60° C. and in particular in the range between 15-30° C. 
     For polyethyleneterephthalate (PET) the thermal treatment temperature T 4  is in particular comprised in the range between 50-85° C. and more in particular in the range between 65-80° C. 
     For polypropylene (PP) the thermal treatment temperature T 4  is in particular comprised in the range between 55-120° C. and more in particular in the range between 85-110° C. 
     With reference to  FIGS. 5 to 10  there is shown an apparatus  101  comprising a plasticising device, for example an extruder  102 , arranged for dispensing plastics in a pasty state. A cutting device is associated with the extruder  102 , which is not shown, that divides the plastics into doses D. 
     The apparatus  101  further comprises a forming carousel  120  provided with a plurality of forming moulds  121 —for example positioned at constant angular intervals on a peripheral zone of the forming carousel  120 —arranged for compression-moulding the doses D to obtain preforms P and for expanding the preforms P to obtain containers C. 
     Each forming mould  121  comprises a punch  122  that cooperates alternatively with a compression-moulding die  123  for compression-moulding a dose D to obtain a preform P and with a blow-moulding die  124  for expanding the preform P to obtain a container C. 
     The forming mould  121  further comprises a neck-forming arrangement  125  arranged for compression-moulding a neck portion of the preform P that is not subsequently deformed when the preform P is expanded. 
     The compression-moulding die  123  comprises a cavity  126  arranged for receiving the dose D. The compression-moulding die  123  is movable along a longitudinal axis of the forming mould  121 . 
     The blow-moulding die  124  comprises a first half mould  127  and a second half mould  128  that are movable towards and away from one another transversely to the longitudinal axis of the forming mould  121 . 
       FIG. 7  shows a step of an operating cycle of the forming mould  121  in which the compression-moulding die  123  is in a lowered position A, in which it does not interact with the punch  122 , the blow-moulding die  124  is in an open configuration X, in which the first half mould  126  and the second half mould  127  are spaced away from one another, and a dose D has been introduced inside the cavity  126 . 
       FIG. 8  shows a subsequent step of the operating cycle of the forming mould  121  in which the compression-moulding die  123  is in a raised position B in which it cooperates with the punch  122  and with the neck-forming arrangement  125  to compression-mould the dose D to obtain the preform P. The blow-moulding die  124  is maintained in the open configuration X to enable the compression-moulding die  123  to move along the longitudinal axis of the forming mould  121  to move from the lowered position A to the raised position B. 
       FIG. 9  shows a subsequent step of the operating cycle of the forming mould  121  in which the compression-moulding die  123  has moved from the raised position B to the lowered position A. The preform P is retained by the neck-forming arrangement  125 . The punch  122  is maintained inside the preform P. 
       FIG. 10  shows a subsequent step of the operating cycle of the forming mould  121  in which the blow-moulding die  124  is in a closed configuration Y in which the first half mould  127  and the second half mould  128  define a forming chamber  129  having the shape of the container C that has to be obtained. 
     A forming element  130  of the punch  122  penetrates inside the forming chamber  129  to stretch the preform P. Simultaneously, the preform P is blown by a forming fluid—for example air—dispensed through conduits obtained in the punch  122 , in particular in the forming element  130 . Alternatively, the preform P can be expanded only through the action of the forming fluid, i.e. without the stretching action exerted by the forming element  130 . 
     In subsequent steps of the operating cycle of the forming mould  121 , the blow-moulding die  124  moves from the closed configuration Y to the open configuration X and the neck-forming arrangement  125  releases the container C. In this manner, the container C can be removed from the forming mould  121  and the forming mould  121  can start a new operating cycle. 
     The apparatus  1  further comprises a moving carousel  131  interposed between the extruder  2  and the forming carousel  120 . The moving carousel  131  removes the doses D from the extruder  102  and inserts the doses D into the forming moulds  121 . The moving carousel  131  further removes the containers C from the forming moulds  121 . On the moving carousel  131 , the containers are positioned according to an angular step that has rather a wide extent. This is due to the fact that the forming moulds  121 , owing to the significant overall dimensions thereof, have to be spaced apart by rather wide angles on the forming carousel  120 . 
     In order to optimise the operation of the devices of the apparatus positioned downstream of the forming carousel  120  it is appropriate to modify, and in particular reduce the distance between the containers C. This enables, for example, more efficient exploitation of the spaces in the aforesaid devices, inasmuch, with the same dimensions of the devices, the number of containers C increases that can be processed simultaneously by the same device. 
     For this purpose, the apparatus  1  is provided with a step-varying carousel  132  that removes the containers C from the moving carousel  131  according to a removal step and delivers the containers C to a conveying device  133  according to a delivery step that is less than the removal step. 
     The conveying device  133  may comprise a conveyor belt  134  that supports a plurality of retaining elements  135 , for example conformed as grippers. In  FIG. 5  and in  FIGS. 11 to 17  only some of the retaining elements  135  supported by the conveyor belt  134  are shown. Each retaining element  135  is separated from the retaining elements  135  adjacent thereto by a distance corresponding to the delivery step. 
     The step-varying carousel  132  comprises a rotary driving device, for example a brushless motor, and a command and control unit that enables the rotation speed of the step-varying carousel  132  to be varied. 
     As shown in  FIG. 11 , the moving carousel  131  comprises a rotating body  136  from which handling elements  137  project that are intended to remove, retain and deliver the containers C. In the embodiment shown three handling elements  137  are present positioned at angular intervals of 120° with respect to the rotating body  136 . The handling elements  137  are provided with a sucking device that enable the handling elements  137  to retain the containers C by depression. Alternatively, other types of retaining devices can be provided, for example a mechanical retaining device. 
     The step-varying carousel  132  comprises a rotating member  138  from which gripping elements  139  project that are intended to remove, retain and deliver the containers C. In the embodiment shown there are three gripping elements  139  positioned at angular intervals of 120° with respect to the rotating member  138 . The gripping elements  139  are provided with a sucking device that enable the gripping elements  139  to retain the containers C by depression. Alternatively, retaining devices of other types can be provided, for example a mechanical retaining device. 
     The moving carousel  131  and the step-varying carousel  132  are positioned in such a manner that, when the rotating body  136  and the rotating member  138  are rotated, the handling elements  137  and the gripping elements  139  define respective circular trajectories that are substantially tangential at a point W near which the containers C are transferred from the moving carousel  131  to the step-varying carousel  132 . 
       FIGS. 12 to 17  show the moving carousel  131 , the step-varying carousel  132  and the conveyor belt  134  in subsequent steps of an operating cycle. 
     With reference to  FIG. 12 , there is shown a step of the operating cycle in which, whilst a gripping element  139   a  runs along an angular portion αl measured from point W, a container C is exchanged between a moving carousel  131  and the step-varying carousel  132 . 
     With reference to  FIG. 13 , there is shown a subsequent step of the operating cycle in which, whilst the gripping element  139   a  runs along an angular portion α 2 , the step-varying carousel  132  rotates at a maximum rotation speed. 
     With reference to  FIG. 14 , there is shown a subsequent step of the operating cycle in which, whilst the gripping element  139   a  runs along an angular portion α 3 , the step-varying carousel  132  decelerates to step from the maximum rotation speed to a minimum rotation speed. 
     With reference to  FIG. 15 , there is shown a subsequent step of the operating cycle in which, whilst the gripping element  139   a  runs along an angular portion α 4 , the step-varying carousel  132  rotates at a constant speed corresponding to the minimum rotation speed until it reaches a further point Z, near which the container C is given to a retaining element  135  of the conveyor belt  134 . 
     With reference to  FIG. 16 , there is shown a subsequent step of the operating cycle in which, whilst the gripping element  139   a  runs along an angular portion α 5 , the step-varying carousel  132  rotates at a constant speed corresponding to the minimum rotation speed. 
     With reference to  FIG. 17 , there is shown a subsequent step of the operating cycle in which, whilst the gripping element  139   a  runs along an angular portion α 6 , the step-varying carousel  132  accelerates to pass from the minimum rotation speed to the maximum rotation speed. In particular, when a further gripping element  139   b , arranged downstream of the gripping element  139   a  with respect to the rotation direction of the step-varying carousel  132 , is at point W the step-varying carousel  132  has reached maximum rotation speed. 
     The apparatus  1  further comprises a cooling and sanitising carousel  140 . 
     The cooling and sanitising carousel  140  cools the containers C, bestowing greater mechanical resistance, in such a manner that the containers C are not deformed in the course of the subsequent operations. This is particularly useful in the case of containers provided with very thick walls, which, at the outlet from the forming carousel  120 , may comprise internal zones formed of plastics having a high temperature and, consequently, being easily deformable. 
     The cooling and sanitising carousel  140  is further provided with nozzles that dispense a sanitising fluid, for example an inert or liquid gas to perform washing of the containers C. The aforesaid washing in particular enables possible odours of plastics to be reduced or even eliminated. In particular, the cooling and sanitising carousel  140  can be received inside a casing that communicates with the outside only through openings of limited extent, arranged to enable the passage of the containers C. The zone enclosed by the aforesaid casing may be maintained in slight overpressure—for example with sanitised air—with respect to the external environment. 
     Instead of the cooling and sanitising carousel  140  two distinct carousels may be provided, one for cooling and one for sanitising, positioned in succession. 
     The apparatus  101  further comprises a filling carousel  110  on which a filling device is provided that fills the containers C with a product, this product being able to comprise a liquid material, a material made of powder or granules, a material made of paste and the like. The aforesaid product can be, for example, a food product or a cosmetic product. 
     The apparatus  101  is provided with a group of first transfer carousels  141 —or possibly a single first transfer carousel—by means of which the containers C are removed from the cooling and sanitising carousel  140  and are transferred to the filling carousel  110 . 
     The apparatus  101  further comprises a capping carousel  112  provided with a capping device arranged for applying caps to the containers C filled with the product. 
     The apparatus  101  is provided with a second transfer carousel  142  arranged for removing the containers C from the filling carousel  110  and delivering the containers C to the capping carousel  112 . 
     The apparatus  101  further comprises a labelling carousel  113  provided with an applicating device arranged for applying labels to the containers C filled with the product. 
     The apparatus  101  is provided with a third transfer carousel  143  arranged for removing the containers C from the filling carousel  110  and delivering the containers C to the capping carousel  112 . 
     With reference to  FIGS. 18 and 19  there is shown an apparatus  201  comprising a plasticising device, for example an extruder  202 , arranged for dispensing plastics in a pasty state. With the extruder  202  a cutting device is associated, which is not shown, that divides the plastics into doses. 
     The apparatus  201  further comprises a supplying carousel  250  that removes the doses and delivers the doses to a compression-moulding carousel  203 . The compression-moulding carousel  203  supports a plurality of compression-moulding moulds each of which is provided with a female half mould provided with a cavity intended to receive a dose and with a male half mould arranged for being received inside the aforesaid cavity. The male half mould and the female half mould cooperate to shape the dose in such a manner as to obtain preforms P. 
     The apparatus  201  further comprises a thermal conditioning device arranged for thermally conditioning the preforms P, for example to prepare the preforms P for a subsequent blowing step P. 
     The thermal conditioning device may comprise a thermal conditioning carousel  208  and/or one or more thermal conditioning tunnels. 
     The apparatus  201  further comprises a moving carousel  251  that removes the preforms P from the compression-moulding carousel  203  and transfers the preforms to the thermal conditioning carousel  208 . 
     The apparatus  1  further comprises a blow-moulding carousel  207  arranged for blowing the preforms  6  to obtain containers. The blow-moulding carousel  207  comprises a plurality of blow-moulding moulds. 
     Downstream of the blow-moulding carousel  207  a filling carousel arranged for filling the containers with a product, and a capping carousel for capping the containers filled and a labelling carousel arranged for labelling the filled containers can be provided. 
     Between the thermal conditioning carousel  208  and the blow-moulding carousel  207  an accumulating arrangement  252  is provided arranged for receiving the preforms P produced by the compression-moulding carousel  203 . 
     In one embodiment, the apparatus  201  does not comprise the thermal conditioning carousel  208 . In this case, the accumulating arrangement  252  is interposed between the compression-moulding carousel  203  and the blow-moulding carousel  207 . 
     The accumulating arrangement  252  comprises a channel  253  inside which the preforms P are supplied one after the other to form a row  254 . The accumulating arrangement  252  further comprises a moving arrangement that moves the preforms along the channel  253 . 
     The accumulating arrangement  252  may comprise devices that prevent the preforms P from knocking against one another—or devices that soften blows—in such a manner that the preforms Pare not damaged during conveying along the channel  253 . 
     The apparatus  201  comprises a first transfer carousel  255  arranged for removing the preforms P from the thermal conditioning carousel  208  and transferring the preforms P to the channel  253  and a second transfer carousel  256  arranged for removing the preforms P from the channel  253  and transferring the preforms P to the blow-moulding machine  207 . 
     The apparatus  201  further comprises a sensor arrangement  257  arranged for detecting the quantity of preforms P present inside the accumulating arrangement means  252 . 
     The sensor arrangement  257  comprises a plurality of sensors arranged in sequence along a direction F along which the preforms P advance along the channel  253 . 
     In particular, the sensor arrangement  257  comprises a first sensor  258 , a second sensor  259  and a third sensor  260 , the first sensor  258  being nearer the blow-moulding carousel  207 , the third sensor  260  being further away from the blow-moulding carousel  207  and the second sensor  259  being interposed between the first sensor  258  and the third sensor  260 . 
     The first sensor  258  detects whether the number of preforms P inside the accumulating arrangement  252  is less than a minimum value, the second sensor  259  provides an indication of the average number of preforms P inside the accumulating arrangement  252  and the third sensor  260  detects whether the number of preforms P inside the accumulating arrangement  252  is greater than a maximum value. 
     In an embodiment that is not shown, instead of the third sensor  260  a plurality of third sensors can be provided interposed between the first sensor  258  and the second sensor  259 . 
     The following is a possible operating mode. 
     If the first sensor  258  detects that the number of preforms P inside the accumulating arrangement  252  is less than the aforesaid minimum value—which corresponds to a situation in which the preforms P inside the channel  253  have finished or are finishing—a command and control unit of the apparatus  201 , connected to the sensor arrangement  257 , stops the blow-moulding carousel  207 . 
     If the third sensor  260  detects that the number of preforms P inside the channel  253  is greater than the aforesaid maximum value, the command and control unit stops the thermal conditioning carousel  208  and the compression-moulding carousel  203 . 
     During normal operation, the command and control unit regulates the speed of the blow-moulding carousel  207  in such a manner that the number of preforms P located inside the accumulating arrangement  252  is comprised between the aforesaid minimum value and the aforesaid maximum value. According to operating mode, if the second sensor  259  does not detect the preforms P the command and control unit decreases the speed of the blow-moulding carousel  207 , whereas if the second sensor  259  detects the preforms P the command and control unit increases the speed of the blow-moulding carousel  9 . 
     With reference to  FIGS. 20 to 22  a version of the apparatus  201  is shown comprising a further accumulating arrangement  262 , provided between the compression-moulding carousel  203  and the thermal conditioning carousel  208 . The further accumulating arrangement  262  comprises a further channel  263  inside which the preforms P are supplied one after the other to form a further row  264 . 
     The apparatus  201  further comprises a further sensor arrangement  267  arranged for detecting the quantity of preforms P found inside the further accumulating arrangement  262 . 
     The further sensor arrangement  267  comprises a further first sensor  268 , a further second sensor  269  and a further third sensor  270 , the further first sensor  268  being nearer the thermal conditioning carousel  208 , the further third sensor  270  being further away from the thermal conditioning carousel  208  and the further second sensor  269  being interposed between the further first sensor  268  and the further third sensor  270 . 
     The command and control unit interacts with the further sensor arrangement  267  to manage the quantity of preforms in the further accumulating arrangement  262 , with the methods disclosed with reference to  FIGS. 18 and 19 . 
     Similarly, an accumulating arrangement cooperating with a respective sensor arrangement can also be provided between the blow-moulding carousel  207  and the filling carousel and/or between the filling carousel and the capping carousel and/or between the capping carousel and the labelling carousel. 
     In these cases, the accumulating arrangement is conformed so as to receive containers, rather than preforms. 
     The accumulating arrangement and the sensor arrangement enable the apparatus  201  to operate with great flexibility. 
     Each of the components of the production line (carousels or devices of another type, for example tunnel conveyors), in fact, can be provided with a dedicated driving arrangement. Owing to the accumulating arrangement and to the sensor arrangement, the speed of each component can be varied to adapt to the speed of the component arranged upstream. Further, owing to the accumulating arrangement and to the sensor arrangement, a component can be maintained in operation, for a certain time, even if the component arranged upstream or downstream has been stopped. 
     With reference to  FIG. 23 , there is shown an apparatus  301  to produce preforms that are subsequently expanded to obtain containers intended for being filled with a product. 
     The apparatus  301  is provided with a plasticising device, for example an extruder  302 , suitable for dispensing plastics in a pasty state. With the extruder  302  there can be associated a cutting device, which is not shown, that divides the plastics into doses. 
     The apparatus  301  is provided with a compression-moulding machine, in particular a compression-moulding carousel  303 , positioned in a first operating zone  309 . The compression-moulding carousel  303  is provided with a plurality of compression-moulding moulds—for example positioned at constant angular intervals on a peripheral zone of the compression-moulding carousel  303 —that compression-mould the doses to obtain preforms Z. 
     Each compression-moulding mould comprises a female half mould and a male half mould, that are movable towards and away from one another, the female half mould being provided with a cavity arranged for receiving a dose and the male half mould being provided with a punch arranged for penetrating inside the cavity to shape the dose. 
     The apparatus  301  further comprises a first transfer carousel  304 , interposed between the extruder  302  and the compression-moulding carousel  303 . The first transfer carousel  304  removes the doses from the extruder  302  and inserts the doses into the compression-moulding moulds. 
     The first transfer carousel  304 , further removes the preforms Z obtained from the compression-moulding moulds and delivers the preforms Z to a second transfer carousel  305 . 
     The apparatus  301  further comprises a blow-moulding machine, in particular a blow-moulding carousel  306 , positioned in a second operating zone  310 . The blow-moulding carousel  306  is provided with a plurality of blow-moulding moulds  307 —for example positioned at constant angular intervals on a peripheral zone of the blow-moulding carousel  306 —that expand the preforms Z to obtain containers. 
     There is provided a thermal conditioning station  308  interposed between the compression-moulding carousel  303  and the blow-moulding carousel  306  and configured for thermally conditioning the preforms Z so as to prepare the preforms Z for blowing. The thermal conditioning station  308  is positioned in a third operating zone  311  interposed between the first operating zone  309  and the second operating zone  310 . 
     The thermal conditioning station  308  comprises a thermal conditioning tunnel. A conveyor  318  is provided that advances the preforms Z along the tunnel of the thermal conditioning station. The conveyor  318  moves along a trajectory, for example of the closed-loop type, in an advancing direction V. 
     In an alternative embodiment, the conditioning station may comprise one or more thermal conditioning carousels and/or one or more thermal conditioning tunnels. 
     Upstream of the thermal conditioning station  308 , in a loading zone C, a transferring wheel  315  is provided that rotates in an opposite direction to the advancing direction V of the conveyor  318 . Upstream of the transferring wheel  315  a third transfer carousel  314  is provided. The third transfer carousel  314  receives the preforms Z that were obtained in the compression-moulding carousel  303  to give the preforms Z to the transferring wheel  315  that, in turn, supplies the preforms Z to the conditioning station  308 , so that the preforms Z can be thermally conditioned. 
     The apparatus  301  comprises a moving arrangement  312  for moving the preforms Z to an intermediate zone  321  between the compression-moulding carousel  303  and the thermal conditioning station  308 . 
     Owing to the moving arrangement  312 , it is possible to advance the preforms Z between the compression-moulding step and the conditioning step, along advance paths that can be selected in function of the type or geometry of the preform, i.e. in function of the time required by this type or geometry of preform to be subjected appropriately to the cooling step. In other words, it is not necessarily necessary to vary the operating speed of the compression-moulding carousel  303  and/or of the blow-moulding carousel  306  to adapt the latter to the speed at which the preforms Z are cooled, as the intermediate zone  321  acts as a temporary accumulation zone in which the preforms Z remain for a time of varying length, depending on the chosen advance path. 
     Owing to the invention, it is thus possible to maintain a high number of containers produced per unit of time, regardless of the type and/or geometry of preforms that are processed. 
     The moving arrangement, in the embodiment shown in  FIG. 23  and, in greater detail, in  FIGS. 24 to 26 , comprises a moving carousel  312  that is rotatable around a first rotation axis R 1  in a first rotation direction R 1 . The moving carousel  312  is placed downstream of the second transfer carousel  305 , and upstream of the third transfer carousel  314 . The second transfer carousel  305  and the third transfer carousel  314  each rotate around a respective rotation axis parallel to the first rotation axis AI and in a rotation direction opposite the first rotation direction R 1 . 
     The moving carousel  312  is provided peripherally with a plurality of supporting carousels  316 , that can be distributed angularly in a uniform manner. Each supporting carousel  316  can rotate around a respective second rotation axis A 2 . 
     In the disclosed example the moving carousel  312  is provided with twelve supporting carousels  316 . In another embodiment it is possible to provide a different number of supporting carousels  316 , depending on the required needs. 
     Each supporting carousel  316  comprises a plurality of seats  317 , each of which is conformed to receiving a respective preform Z. In the example shown in  FIGS. 24 to 26  each supporting carousel  316  is provided with four seats  317  angularly distributed in an equidistant manner from one another, but it is possible to provide a different number of seats  317 . 
     Each supporting carousel  316  is mounted rotatably on the moving carousel  312 . Each supporting carousel  316 , by rotating with respect to the moving carousel  312 , enables each of the seats  317  thereof to interact with the second transfer carousel  305  and/or with the third transfer carousel  314  respectively to receive and give a preform Z. 
     The supporting carousels  316 , as also the moving carousel  312 , and/or other rotatable components of the apparatus, can rotate continuously or by angular steps. 
     The moving carousel  312 , and then the supporting carousels  316  thus configured, are able to retain the preforms Z for a considerable time, if this is necessary for given types or geometries of preform. In this manner it is not necessary to have to slow down operation and thus the productivity of the compression-moulding carousel  308  to enable the preforms Z to cool. 
     The moving carousel  312  and the supporting carousels  316  act as an accumulating arrangement for the preforms Z. In other words, it is possible to drive each supporting carousel  316  so as to receive one or more preforms Z each in a respective seat  317  depending on whether a lesser or greater period of time is required for the cooling step. In this manner, the preforms Z are advanced by the supporting carousels  316  along advance paths having a desired length and chosen selectively so as to vary the dwelling time on the moving carousel  312 . 
     The apparatus  301  that is thus configured defines a production line having high productivity in relation to reduced overall dimensions. Each of the components of the apparatus  301  can be provided with a dedicated driving arrangement. Owing to the moving carousel  312  which acts as an accumulating device, the speed of each component can, in a certain manner, can be made independent of the speed of the component arranged upstream. It is further possible to maintain a component in function, for a certain time, even if the component arranged upstream, or downstream, has been stopped. 
     The supporting carousels  316  can be rotated with respect to the respective second rotation axes A 2  such as to make thermal conditioning possible, in particular a cooling step, only in certain and defined angular positions, or it is possible to provide a cooling step that is active for all the time in which the supporting carousels  316  rotate. This can improve the thermal uniformity of the preforms and, particularly on each of the parts thereof, for example if there are thicknesses of the preforms Z that are variable from one zone to another zone. 
     The supporting carousels  316  can be driven, i.e. rotated continuously or be rotated by successive angular steps independently from one another. 
     The moving carousel  312  can be provided with a cooling system which enables the preforms Z to be cooled appropriately that are supported by the moving carousel  312 . The cooling system may comprise a plurality of cooling devices, each of which is associated with a respective supporting carousel  316 . In an embodiment it is possible to provide a cooling device for each of the seats  317  of each supporting carousel  316 . 
     The cooling device may provide suitable chambers inside which the preforms Z are received, the chambers being able to be closed above and below. The cooling device can be configured to send a cooling fluid both to internal surfaces of the preforms and to external surfaces of the preform. In one embodiment, it is possible to provide closing devices that bound, on each supporting carousel  316 , sector zones, in each of which a respective preform is received. The closing devices may comprise dividing-wall elements distributed in an equidistant manner by the respective preforms. 
     It is possible to configure the cooling system so as to act in a different manner according to the position that the preforms Z adopt whilst they are dragged by the moving carousel  312 . Cooling can, for example, be by flows of air and/or gas that are introduced into the aforesaid cooling chambers. The flows of air and/or gas can be directed to the preform in a coaxial manner or according to directions chosen in order to localise cooling in determined zones. It is possible, for example, to act to cool the external and the internal surfaces of the preforms Z in a different manner, depending on the different temperature values that obtain in various zones of the preform. For example the cooling device can take into account the fact that the temperature of the external surfaces of the preforms Z, at the end of compression-moulding, is less than the temperature of the internal surfaces. 
     Below, some operating methods of the moving carousel  312  and of the supporting carousels  316  are disclosed in greater detail below to explain the operation thereof better. 
     In  FIG. 24  there is shown a first operating mode of the moving carousel  312  and of the supporting carousels  316 . In the first operating mode each supporting carousel  316  is not rotated with respect to the moving carousel  312 , but is dragged only by the latter, which in turn rotates around the first rotation axis AI. In other words, the supporting carousels  316  do not rotate around the respective second rotation axes A 2 . In this manner, only one side  317  of each supporting carousel  316  is used, in particular the seat  317  positioned nearer the peripheral zone of the moving carousel  312 . Each preform Z is thus transferred from the second transfer carousel  305  to a seat  317  in a first position P 1 , and is conducted via rotation of the moving carousel  312  to a second position P 2 , in which each preform is given to the third transfer carousel  314 . In this manner, each preform moves along a first path that corresponds to a substantially semicircular trajectory. 
     A very reduced dwelling time of the preforms Z on the moving carousel corresponds to this first path. This is useful when the geometry and/or the type of preforms Z are such as to permit very rapid cooling steps. 
       FIG. 25  shows a second operating mode in which the dwelling time of the preforms on the moving carousel  312  is increased with respect to the first operating mode that has just been described. Of each supporting carousel  316  only two of the four available seats  317  are used. In particular, two seats  317  are used that are diametrically opposite one another. 
     For each supporting carousel  316  that is located in the first position P 1 , a first preform Z 1  is received in a first seat  17   a  arranged more peripherally with respect to the moving carousel  312  and nearer the second transfer carousel  305 . Once the first preform Z 1  is received, the supporting carousel  316 , which in the meantime is rotatingly dragged by the moving carousel  312 , rotates around the own second rotation axis A 2  by approximately 180°. In this manner, the first seat  317  containing the first preform Z 1  that has just been received is moved to a position diametrically opposite the previously occupied position (with respect to the second rotation axis A 2 ). In other words, the first preform Z 1  is moved from a more peripheral position to a central zone of the moving carousel  312 . When the supporting carousel  316  is conducted to the position P 2 , in the meantime a preform Z 0  already previously received by the moving carousel  312  with respect to the first preform Z 1 , and which is thus suitably cooled, is given to the third transfer carousel  314 . 
     In the meantime, the moving carousel  312  continues to rotate and takes the supporting carousel  316  under examination again to the second transfer carousel  305  in the first position P 1 , in such a manner that a second seat  17   b , diametrically opposite the first seat  317  can receive a second preform. At this point, the supporting carousel  316  is rotated around the own second rotation axis A 2  by a further angle equal to approximately 180° in such a way as to return the first seat  317  to a more peripheral position on the moving carousel  312 . In this manner, the first seat  317  can interact, in the second position P 2 , with the third transfer carousel  314 , giving to the latter the first preform. At this point, the moving carousel  312  continues to rotate and the first seat  317 , which is now free, is again moved to the second transfer carousel  305  to receive the third preform. Subsequently, the supporting carousel  316  is rotated by a still further angle of 180° so as to give also the second preform to the third transfer carousel  314  in the second position P 2  and so on. 
     What has just been described applies to each of the supporting carousels  316 . In substance, in this operating mode, each preform is retained on the moving carousel  312  in such a way as to define a second path corresponding substantially to one and a half revolutions of the moving carousel  312 . In such a manner a dwelling time is used that is three times the dwelling time associated with the first operating mode disclosed above, i.e. if the second transfer carousel  305  and the third transfer carousel  314  are located in positions that are diametrically opposed to one another with respect to the moving carousel  312 . 
       FIG. 26  shows a third operating mode that enables all four seats  317  of each supporting carousel  316  to be exploited. In this operating mode, the dwelling time of the preforms Z on the moving carousel  312  is at maximum with respect to the previously disclosed cases. Each supporting carousel  316 , whilst it is conveyed by the moving carousel  312  from the first position P 1  to the second position P 2 , rotates around the respective second axis A 2  by a quarter revolution so as to give a now cooled preform Z to the third transfer carousel  314 . The seat that is freed receives a further preform Z from the second transfer carousel  305  and so on. In this case—in which there are four seats  317  for each supporting carousel  316 —each supporting carousel  316  rotates around the second rotation axis A 2  by successive angles equal to approximately 90° in such a manner that each seat  317 , in a sequential manner receives a preform Z and subsequently gives the preform Z after a set number of revolutions of the moving carousel  312 . In this case each preform Z moves along a path having a length corresponding to three and a half revolutions of the moving carousel  312 . 
     The dwelling time in this operating mode is seven times that of the first operating mode disclosed above. 
     Obviously, and in an operating mode that is similar to what has been seen so far, one operating mode is provided that is not shown in which three of the four seats  317  of each supporting carousel  316  are used. 
     A similar operation moving carousel  312  to what is disclosed above is provided if there is a different number of supporting carousels  317  and/or a different number of seats  317  on each supporting carousel  316 . 
     In the various embodiments of the apparatus  301  disclosed above, it is possible to provide on the moving carousel  312  a heating device that acts on the preforms Z, after the cooling step, so as to perform a slight heating step on the latter. The heating device can act selectively on certain critical parts of each preform Z that need to be prepared for the subsequent and more thorough step of thermal conditioning that occurs in the thermal conditioning station  308 . In this manner it is possible to eliminate or substantially reduce possible thermal imbalances in the preforms Z. 
     The heating device can act at set angular positions of each supporting carousel  316  and/or of the moving carousel  312 . 
     The preforms Z, after remaining on the moving carousel  312  for the time necessary for cooling, are given to the third transfer carousel  314 , which in turn delivers the preforms Z to the transferring wheel  315 . The transferring wheel  315 , lastly, transfers the preforms Z to the conditioning station  308  where the preforms Z can receive suitable thermal treatment that has the purpose of preparing the preforms Z for successive blow-moulding on the blow-moulding carousel  306 . 
     Downstream of the conditioning station  308  there is provided a fourth transfer carousel  319 , suitable for transferring the preforms Z exiting the conditioning station  308  to the blow-moulding carousel  306 . Downstream of the conditioning station  308  a fifth transfer carousel  320  is provided that is used to remove from the blow-moulding carousel  306  the containers obtained from the preforms Z and send the containers to possible operating stations located further downstream. Such operating stations may comprise, for example, a filling station for filling the containers with a product, for example a liquid material, a powder or granule material, a paste material and the like. The aforesaid product can be, for example, a food product or a cosmetic product. It is possible also to provide a closing or capping station to close the containers that are possibly filled and/or a labelling station for the containers. 
     With reference to  FIG. 23 , the apparatus  301  comprises a storage station  322 , positioned in a storing zone ( 332 ) and provided, for example, with a hopper  323  suitable for containing preforms. 
     A bypass device  328  is provided that enables the preforms to be directed to the storage station  322 . In this manner it is possible to conserve the compression-moulded preforms that do not have to be sent immediately to the blow-moulding carousel  306  but can be processed subsequently. The storage station  322  can also receive preforms that have been produced elsewhere, for example injection-moulded preforms. 
     The bypass device  328  comprises a bypass conveyor  324  that connects the moving carousel  312  to the hopper  323 . The bypass conveyor  324  can be, for example, of the belt or chain type. 
     The bypass device  328  comprises a removing wheel  331  suitable for removing the preforms Z from the moving carousel  312  to position the preforms Z on the bypass conveyor  324 . 
     Owing to the embodiment of the apparatus  301  in  FIG. 23 , it is possible to produce preforms Z and conserve the preforms Z for any period of time that is desired, postponing the blow-moulding of the preforms Z to a subsequent moment. In this operating mode, it may be necessary to perform more thorough cooling of the preforms Z on the moving carousel  312 , to prevent the preforms Z possibly being damaged in the subsequent conveying and storage steps. For this purpose, it is possible to increase the dwelling time of the preforms Z on the moving carousel  312 , operating the latter, for example in the second operating mode, disclosed with reference to  FIG. 25 , or in the third operating mode, disclosed with reference to  FIG. 26 . The operating mode of the moving carousel  312  can be varied by acting on a control unit and setting a change to the operating programme. 
     The preforms Z are cooled on the moving carousel  312  so as to have a temperature below a set value in order to avoid crystallisation thereof. In one embodiment, on the second transfer carousel  305  there can be provided an air and/or gas cooling arrangement configured for thermally conditioning the preforms Z in a preliminary manner, i.e. in such a manner as to anticipate the thermal conditioning that subsequently takes place on the moving carousel  312 . Also in this case, the cooling arrangement can be configured for acting in a selective manner on given zones of the preforms Z, and/or at determined angular positions of the second transfer carousel  305 . 
     The apparatus  301  can be provided with a discarding device that discards the preforms having certain defects that are detectable with suitable vision systems. The discarding device can be provided on the removing wheel  331  and/or on the third transfer carousel  314 . 
     A supplying system  326  is further provided that is suitable for removing the preforms stored in the storage station  322  to insert preforms into the production line defined by apparatus  301 . 
     The supplying system  326  comprises a supplying conveyor  325  suitable for conveying the preforms from the storage station  322  to the conditioning station  308 . 
     Downstream of the supplying conveyor  325  there is provided a further transferring wheel  327 , suitable for transferring the preforms coming from the storage station  322  to the conditioning station  308 . In particular, the further transferring wheel  327  transfers the preforms from the supplying conveyor  325  to the conveyor  318  of the conditioning station  308  in a further loading zone D, opposite the loading zone C, with respect to the conveyor  318 . The further transferring wheel  327  is connected so as to be upstream of the transferring wheel  315  with respect to the advancing direction V of the conveyor  318 . In this manner, the preforms that arrive from the storage station  322  and that may thus require a more thorough thermal conditioning step with respect to the preforms coming from the compression-moulding carousel  303 , can travel, via the conveyor  318 , along a trajectory of greater length inside the conditioning tunnel. 
     The supplying system  326  and/or the supplying conveyor  325  is configured for suitably orientating the preforms removed from the storage station  322 . 
       FIG. 27  shows another apparatus embodiment  301  that differs from the embodiment disclosed with reference to  FIG. 23  inasmuch as the bypass device  328  is not provided. In this case, the apparatus  301  can process preforms that have just been obtained in the compression-moulding carousel  303  or preforms that are removed from the storage station  322  and were previously obtained. The preforms coming from the storage station  322  can be of a different nature, for example they can be produced by injection moulding in a production plant that is distinct from the apparatus  301 . 
     With reference to  FIG. 28 , there is shown a still further embodiment of the apparatus  301  that is different from the preceding embodiments inasmuch as neither the bypass device  328  nor the storage station  322  and thus the supplying system  326  are provided. 
     In this embodiment, the apparatus  301  comprises a conditioning station  329  similar to that disclosed in the apparatus embodiments  301  shown in  FIGS. 23 and 27  but provided with a conditioning tunnel of reduced length. A further conveyor  330  is provided that advances in a further advancing direction V′. In this case, the transferring wheel  315  is positioned at an end of the tunnel that is nearer the fourth transfer carousel  319 . 
     The preforms that are dropped from the transferring wheel  315  to the further conveyor  330  run along the tunnel first in one direction, away from the fourth transfer carousel  319 , and then in the opposite direction, towards the fourth transfer carousel  319 . Owing to this configuration, it is possible to thermally conditioning the preforms in an effective manner and simultaneously the overall dimensions associated with the conditioning station  308  are reduced significantly. 
     Variations and/or additions to what has been disclosed and illustrated in the enclosed drawings are possible. 
     In particular, any moving arrangement can be used that defines advance paths of variable lengths so as to be able to obtain variable dwelling times of the preforms between the compression-moulding and the thermal conditioning zones of the preforms.