Apparatus for the production of a cement agglomerate and corresponding method

Abstract

 An apparatus for the production of a cement agglomerate comprises containing means (12), into which raw materials are loaded, mixing means (13, 15), to mix the raw materials with at least a liquid substance, introduction means (37, 39) and discharge means (16), the latter being provided in order to render the cement agglomerate available for use. The mixing means comprise a first mixer (13) and a second mixer (15) to mix the cement agglomerate obtained, while the discharge means (16) unload it from second containing means (45).

Description

FIELD OF THE INVENTION

[0001] The present invention concerns an apparatus for the on-site production of a cement agglomerate, advantageously but not exclusively aerated cement, and the relative production method.

[0002] In particular, the apparatus for the production of cement agglomerate is provided with a loading hopper into which the compounds of the cement agglomerate are loaded, and with mixing means that provide to mix the components so as to define a homogeneous mix of concrete with the desired consistency that is then pumped to the destination zone.

BACKGROUND OF THE INVENTION

[0003] Apparatuses are known for the production of cement agglomerates such as concrete, aerated cement, hydraulic cement or suchlike, in which the components that make up the cement agglomerate are suitably mixed so as to define a homogeneous compound with the desired consistency that allows it to be used on site.

[0004] In particular, apparatuses are known for the production of aerated cement, such as cement mixers or spiral mixers, which comprise a loading hopper through which the cement is introduced, and possibly also other components. From the loading hopper the cement is introduced into a mixer which provides to mix it with water and foam, suitably produced by a foam generator.

[0005] In the building trade it is also known to make cement agglomerates which incorporate not only water and cement, but also polymer materials, such as expanded polystyrene, or recycled plastic.

[0006] In particular, cement compounds are known that are obtained from premixed cement, recycled plastic and possibly sand, which are introduced into the apparatus and which, once laid, following mixing, increase the characteristics of heat and sound insulation of the cast, and also reduce the weight. It is also known that the plastic is in the form of flakes of about 10 mm, with an apparent density of 200-300 kg/m³.

[0007] A pumping device, for example a screw pump, located downstream of the mixer and independent of it, provides to pump the cement agglomerate obtained through pipes and toward the site for the cast and to make foundations for floors or heat insulating walls.

[0008] More specifically, the cement agglomerate previously obtained in the mixer is pumped to a loading hopper of the pumping device which, in turn, provides both to mix and also to pump the cement agglomerate toward the destination zone.

[0009] One disadvantage of known apparatuses is that once a first mix of the cement agglomerate has been obtained, it is necessary to transfer it completely to the pumping device before starting to mix it again. During this interval of time the cement agglomerate is not mixed, and there is a risk of generating agglomerates which can obstruct the pipes during the pumping step.

[0010] Furthermore, during the time while the cement agglomerate is stationary, it is subject to a loss of consistency which reduces the desired density and therefore does not allow to respect the insulating properties of the cast that is then made.

[0011] Another disadvantage is that known apparatuses take a very long time to produce the concrete, especially due to the fact that it is necessary to make a first complete mixing in the mixer, then transfer it to the external mixer, to mix it in the external mixer and then pump it to the place where it is laid.

[0012] Apparatuses are also known for the production of cement agglomerates, for example those described in documents BE-A-893.802 and EP-A-1.175.936, in which a first mixer is provided, configured to mix cement, possibly with sand, arriving from a loading hopper, with water and foam suitably produced by a foam generator. In this way a first cement mix is obtained. The apparatus also comprises a second mixer, in which the first cement mix is kept stirring so as to prevent it from drying out, and the formation of lumps.

[0013] One disadvantage found in these known machines is that they are particularly subject to blockages already in the first mixer. This problem is even more common if cement mixes are used that also have recycled plastic materials among their components.

[0014] One purpose of the present invention is to obtain an apparatus for the production of a cement agglomerate which is homogeneous, which does not lose its consistency before it is used and which prevents the formation of lumps that could obstruct the passage through the pipes, or blockages that could block the functioning of the apparatus.

[0015] Another purpose of the present invention is to obtain an apparatus for the production of a cement agglomerate which is simple to make and compact.

[0016] Another purpose of the present invention is to obtain an apparatus which allows to obtain the cement agglomerate quickly.

[0017] Another purpose of the present invention is to reduce the maintenance interventions on the apparatus, or problems connected to temporary interruptions of its functioning.

[0018] Another purpose is to perfect a method for the production of cement agglomerate which is simple, quick and which allows to obtain a homogeneous cement agglomerate with the desired properties.

[0019] The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.

SUMMARY OF THE INVENTION

[0020] The present invention is set forth and characterized in the independent claims, while the dependent claims describe other characteristics of the invention or variants to the main inventive idea.

[0021] In accordance with the above purposes, an apparatus for the production of a cement agglomerate comprises first containing means into which raw materials are loaded, constituting at least part of the cement agglomerate, and a first mixer to mix the raw materials with at least a liquid substance, such as water, which is introduced into it by introduction means. The apparatus also comprises a second mixer associated with second containing means to mix the cement agglomerate obtained by mixing the raw materials with water in the first mixer.

[0022] Discharge means are provided to make the cement agglomerate available for use and subsequent laying.

[0023] According to one feature of the present invention, the first mixer is provided with at least a first mixing section disposed in proximity to the first containing means, and a second mixing section disposed in proximity to the introduction means. In the first section the raw materials are mixed to reduce the presence of possible cement lumps that could be present when they are introduced, in the second section the raw materials are mixed at least with water to define the cement agglomerate that will be unloaded into the second mixer.

[0024] Furthermore, the second section is provided with a blading having at least a blade shaped as a spiral attached to a rotation shaft and kept distanced from the latter so as to define, between the spiral shaped blade and the rotation shaft, an interspace for the passage of the raw materials.

[0025] The particular conformation of the blading of the second mixing section allows to prevent the formation of blockages in the machine, as happened with apparatuses described in the state of the art.

[0026] The spiral shaped blade exerts on the cement agglomerate that is forming an action of feeding it toward the second mixer, while the interspace for the passage of the raw materials exerts a mixing action on the cement agglomerate, preventing blockages.

[0027] This conformation is particularly advantageous also if raw materials are used that have polymer components such as plastic flakes with sizes comprised between 8mm and 15mm.

[0028] The second mixer provides to keep stirring the cement agglomerate contained in the second containing means, performing a function of further homogenization and also preventing the aggregation of the cement agglomerate. In this way it is possible to avoid problems of blocking of the discharge means and problems in the variation of consistency and density of the cement agglomerate due to possible downtimes to which the cement agglomerate was subjected with state-of-the-art machines.

[0029] Some forms of embodiment provide that the spiral shaped blade is attached to the rotation shaft by means of connection elements such as welded blades, threaded connection members, brackets or similar or comparable elements.

[0030] In other forms of embodiment the spiral shaped blade has a length, in the radial direction, comprised between 0.75 and 0.95, preferably between 0.80 and 0.90, even more preferably about 0.85 with respect to the size of the interspace.

[0031] Other forms of embodiment provide that the spiral shaped blade has an angle of inclination of the spiral comprised between 45° and 65°, preferably between 50° and 60°, even more preferably between 55° and 59°. The angle of inclination of the spiral consequently determines the pitch of the spiral.

[0032] According to another feature, the second section of the first mixer is provided with a plurality of spiral shaped blades attached to the rotation shaft one after the other and angularly staggered. By angularly staggered we mean that the shaped blades are not disposed in direct continuity of the helical development. This particular conformation allows to further increase the stirring and mixing effect of the raw materials.

[0033] According to another form of embodiment, in the second section, as well as the spiral shaped blade, the rotation shaft is provided with a plurality of auxiliary blades attached to the rotation shaft and each extending in a radial direction, and which allow to increase the mixing and stirring action of the raw materials to define the cement agglomerate.

[0034] According to one form of embodiment, in the first mixer, an intermediate section is interposed between the first section and the second section, to transfer the raw materials from the first section to the second section. The intermediate section allows to physically divide the first from the second mixing section, allowing a dosing action of the raw materials that are transferred to the second section.

[0035] According to another feature of the invention, the rotation shaft extends longitudinally through the first section, the second section and the intermediate section, and is suitable to support respective bladings in each of the sections.

[0036] The intermediate section is provided with bladings conformed as spirals to separate the first section from the second section and to prevent any reflux of material from the second to the first section.

[0037] According to another form of embodiment, the introduction means comprise at least a first pumping device and a second pumping device provided to introduce into the second section respectively water and foam to lighten the cement agglomerate.

[0038] It is advantageous to provide that the water and foam are introduced into the second section independently from each other to allow them to be accurately dosed. The introduction of foam into the cement agglomerate allows to obtain for example aerated cement with insulating properties, both heat and acoustic, of the article obtained.

[0039] According to another form of embodiment of the invention, the second mixer comprises a first shaft to which spiral shaped bladings are solidly associated. The discharge means comprise a pumping device provided with a second shaft solid with the first shaft so that an identical rotation of the second shaft corresponds to a rotation of the first shaft. Furthermore, the apparatus comprises a single actuation member to actuate the second mixer and the pumping device.

[0040] The pumping device is configured to pick up the cement agglomerate from the second containing means and pump it to a destination of use.

[0041] According to another feature, the second containing means are provided with lateral walls and a bottom wall in proximity to which, and for its whole longitudinal extension, the second mixer is disposed.

[0042] According to another form of embodiment, the first shaft has its respective axis of rotation substantially parallel to the bottom wall.

[0043] According to another form of embodiment, the second rotation shaft is solidly associated with the first shaft of the second mixer by means of a joint element. This is made possible by the particular disposition of the pumping device and the second mixer which are disposed substantially in reciprocal continuity and coaxial. This particular conformation allows to greatly reduce the bulk of the apparatus according to the present invention and make it simple and economical to make and to manage.

[0044] Some forms of embodiment also concern a mixing section of a cement agglomerate which comprises a blading having at least a spiral shaped blade attached to a rotation shaft and kept distanced from the latter so as to define an interspace between the spiral shaped blade and the rotation shaft, for the passage of the raw materials.

[0045] Some forms of embodiment of the present invention provide that the first containing means, the first mixer, the introduction means, the second mixer and the discharge means are grouped together in a single unit, advantageously of the transportable type.

[0046] The present invention also concerns a method for the production of a cement agglomerate that uses a machine as described above.

BRIEF DESCRIPTION OF THE DRAWINGS

[0047] These and other characteristics of the present invention will become apparent from the following description of a preferential form of embodiment, given as a non-restrictive example with reference to the attached drawings wherein:

• fig. 1 is a lateral view of an apparatus for the production of a cement agglomerate according to the present invention;
• fig. 2 is a front view of fig. 1;
• fig. 3 is a rear view of fig. 1;
• fig. 4 is a partly sectioned view of fig. 1;
• fig. 5 shows a variant of fig. 4;
• fig. 6 shows an enlarged detail of fig. 5.

[0048] To facilitate comprehension, the same reference numbers have been used, where possible, to identify identical common elements in the drawings.

DETAILED DESCRIPTION OF SOME FORMS OF EMBODIMENT

[0049] With reference to the attached drawings, an apparatus for the production of a cement agglomerate 10 according to the present invention comprises a bearing structure 11 on which are mounted first containing means, in this case a first hopper 12 for loading the compounds that make up the cement agglomerate, a first mixer 13, a second mixer 15 disposed downstream of the first, and a pumping device 16 suitable to pump the cement agglomerate to the laying site.

[0050] The whole bearing structure 11 is provided to support inside itself at least the components described above, achieving a compact structure that can be easily transported, even by road, thanks to the fact that it is mounted on wheels provided to move it.

[0051] The first hopper 12 (fig. 4) comprises a loading compartment 17 defined by lateral walls 18 and a bottom wall 19, and into which at least some of the raw materials that make up the cement agglomerate are loaded.

[0052] Some forms of embodiment of the invention provide that the apparatus 10 according to the present invention is suitable to work raw materials comprising water, cement, recycled plastic and possibly sand. In particular, if recycled plastic is used, it has an average size of about 10mm and an apparent or bulk density comprised between 200kg/m³ and 300kg/m³.

[0053] In proximity to the bottom wall 19 (figs. 4 and 5) of the loading compartment 17 a part of the first mixer 13 is disposed, which extends beyond the bulk of the first hopper 12.

[0054] The first mixer 13 comprises a plurality of mixing sections and in this case a first section 21, a second section 23 and an intermediate section 22, interposed between the first section 21 and the second section 23. The first section 21 extends substantially for the length of the bottom wall 19, and provides to mix the raw materials introduced through the first hopper 12, thus obtaining a homogeneous composition thereof.

[0055] The intermediate section 22 is suitable to discharge the raw materials from the first hopper 12 to the second section 23, dosing the quantity that is picked up from the first hopper 12.

[0056] In the second section 23, the raw materials introduced into the first hopper 12 are mixed with water, foam and possibly other additives.

[0057] The first mixer 13 is provided with a rotation shaft 25 that extends for the whole length of the first section 21, the second section 23 and the intermediate section 22. In the form of embodiment shown in fig. 5, the rotation shaft 25 comprises a first segment 25a that extends for the length of the first section 21 and the intermediate section 22, and a second segment 25b that extends for the length of the second section 23.

[0058] The first segment 25a (figs. 4 and 5) and the second segment 25b are reciprocally connected by connection means, for example threaded, flanged or jointed connections, or by similar or comparable connection means suitable for the purpose.

[0059] The rotation shaft 25 is provided with a plurality of bladings having different configurations in the first section 21, second section 23 and intermediate section 22, which can be mounted or connected to the rotation shaft 25 by connection means or by welding.

[0060] In particular (fig. 4), in correspondence with the first section 21, intermediate section 22 and second section 23, respectively first bladings 26, second bladings 27 and third bladings 28 are provided.

[0061] In the form of embodiment shown in figs. 4 and 5, the rotation shaft 25 is made to rotate by a single drive member 30 which is keyed in proximity to the end of the rotation shaft 25 that supports the first bladings 26.

[0062] In other forms of embodiment it may be provided that the first segment 25a and respectively the second segment 25b of the rotation shaft 25 are made to rotate independently of each other, for example by respective drive members.

[0063] The first bladings 26 (fig. 4) are conformed as blades, extend radially with respect to the rotation shaft 25 and are disposed so that the width of their section is disposed transversely with respect to the axial direction of the rotation shaft 25.

[0064] In particular, the first bladings 26 are inclined with respect to the axis of rotation of the rotation shaft 25 by an angle of inclination α (fig. 5) of about 30° with respect to the direction of feed of the raw materials.

[0065] Merely by way of example, and not restrictive of the present invention, the first bladings 26 have a rectangular section and a length in a radial direction comprised between 40 and 60 mm.

[0066] The first bladings 26 perform both a function of feeding the raw materials loaded into the first hopper 12, caused by the particular inclination of the first bladings 26, and also a function of breaking up any lumps that might be present.

[0067] An aperture 31 is made on one of the lateral walls 18 (figs. 4 and 5) of the first hopper 12, and in correspondence with the bottom wall 19.

[0068] In correspondence with the aperture 31 a first pipe 32 is connected, in which the intermediate section 22 of the first mixer 13 is housed.

[0069] The second bladings 27 of the intermediate section 22 are spiral shaped and have the function of feeding the cement toward the second section 23 of the first mixer 13.

[0070] The particular conformation of the second bladings 27 allows to separate the first section 21 from the second section 23, and prevent a reflux of material from the second section 23 to the first section 21.

[0071] By way of example, the second bladings 27 have a diameter of about 90mm and a pitch of the spiral that varies from 70mm to 90mm, to define an angle of deflection, or angle of the spiral, comprised between 60° and 80°.

[0072] The spiral of the second bladings 27 is defined by a shaped blade which is attached to the first part 25a of the rotation shaft 25 and extends continuously for the whole radial development thereof.

[0073] The second section 23 of the first mixer 13 is housed inside a second pipe 33 which is associated substantially continuous with the first pipe 32, and has a section size greater than the latter.

[0074] In the form of embodiment shown in fig. 4, the third bladings 28 of the second section 23 of the first mixer 13 are also conformed as blades, and are solidly associated to the respective rotation shaft 25, for example by welding, disposing them with their longitudinal development substantially radial with respect to the shaft 25 and with their width disposed transversely to the axial direction of the shaft 25.

[0075] According to another form of embodiment (figs. 5 and 6), the third bladings, indicated here by the reference number 128, have a conformation of the helical type and are independent of the rotation shaft 25. In particular, the third bladings 128 comprise a shaped blade 129 (fig. 6) that affects part of the diameter of the second pipe 33. The shaped blade 129 has a helical profile and is attached to the second part 25b of the rotation shaft 25 by connection elements 130.

[0076] The connection elements 130 keep the shaped blade 129 distanced from the rotation shaft 25, so that it only partly affects the diameter of the second pipe 33. An interspace 131 is defined between the rotation shaft 25 and the shaped blade 129, for the passage of the material which, in this portion, is not subjected to any thrust action but to a mixing action.

[0077] In the form of embodiment shown in fig. 6, the rotation shaft 25 has an external radius Ra, the third blading 128 has an internal radius Ri which is greater than the external radius Ra of the rotation shaft 25, and an external radius Re which is substantially the same as the internal radius of the second pipe 33. The interspace 131 has a size G which is determined by the difference between the internal radius Ri of the third blading 128 and the external radius Ra of the rotation shaft 125.

[0078] Merely by way of example, the shaped blade 129 has a length L, in a radial direction, that is, given by the difference between the external radius Re and the internal radius Ri that is comprised between 30mm and 50mm.

[0079] Some forms of embodiment provide that the ratio between the length L of the shaped blade 129 and the size G of the interspace 131 is comprised between 0.75 and 0.95, preferably between 0.80 and 0.90, even more preferably about 0.85.

[0080] Applicant has found that, with these ratios, problems in the blocking of the first mixer 13 are avoided, and an optimum mixing of the material passing through it is obtained.

[0081] In the form of embodiment shown in fig. 6, the spiral of the shaped blade 129 has an angle of inclination β comprised between 45° and 65°, preferably between 50° and 60°, even more preferably between 55° and 59°.

[0082] Merely by way of example, the spiral of the shaped blade has a pitch P of about 250mm, which is determined by the angle of inclination β.

[0083] In the form of embodiment shown in fig. 6, the third blading 128 comprises two shaped blades 129 disposed one after the other and angularly staggered by about 180°. The stagger of the shaped blades 129 interrupts the continuous transfer of the material passing in the first mixer 13, in this way increasing the mixing action thereof. In this case, both the shaped blades 129 extend only for the length of one pitch P.

[0084] Other forms of embodiment can provide one or more than two shaped blades 129 disposed one after the other. In the same way, it is possible to provide different angles of reciprocal stagger between one shaped blade 129 and the one adjacent to it.

[0085] The rotation shaft 25, in its second part 25b, as well as the shaped blade 129, is provided with a plurality of auxiliary blades 132 attached to the rotation shaft 25 and each extending in a radial direction.

[0086] In particular, the auxiliary blades 132 are disposed inclined by an angle of inclination y, in the direction of feed of the material, comprised between 20° and 40°, preferably between 25° and 30°.

[0087] The auxiliary blades 132 allow to increase the mixing and stirring action of the material passing in the first mixer 13.

[0088] In the second pipe 33 (fig. 4) and in proximity to the center line of its longitudinal extension, two through holes are made, only one of which is visible in the drawings, with which a first tube 35 and respectively a second tube 36 are connected.

[0089] In particular, the first tube 35 is provided to bring water inside the second section 23 and to adjust the consistency of the mix of the cement agglomerate to be obtained.

[0090] The second tube 36 is provided to bring foam to the mix generated, which confers the desired density on the cement agglomerate.

[0091] Merely by way of example, with the apparatus according to the present invention it is possible to obtain aerated cement with a density comprised between 300 kg/m³ and 600 kg/m³, preferably about 400 kg/m³.

[0092] A first pumping device 37 (fig. 1) is associated with the first tube 35 to feed the water into the second pipe 33.

[0093] The foam is generated by a foam generating device 40 (fig. 3), of a known type, which provides by means of a second pumping device 39 to feed the foam through the second tube 36 into the second pipe 33.

[0094] In the second section 23 of the first mixer 13, the water and then the foam are added to the raw materials in the desired quantities.

[0095] In other forms of embodiment it may be provided that other additives, as well as water and foam, may be inserted in the second pipe 33. In this case, suitable tubes to feed said additives will be provided.

[0096] The larger size of the section of the second pipe 33, compared with that of the first pipe 32, allows to define in it a mixing chamber in which the cement agglomerate can be homogenized.

[0097] The second pipe 33 (figs. 4 and 5) is provided with a discharge aperture 43, in this case facing downward, through which the cement agglomerate already mixed is discharged to feed it to the second mixer 15.

[0098] In particular, the cement agglomerate is discharged from the first mixer 13 into second containing means, in this case a second hopper 45 comprising lateral walls 46 and a bottom wall 47.

[0099] The second mixer 15 is disposed in proximity to and for the whole extension of the bottom wall 47 of the second hopper 45, to keep the previously mixed cement agglomerate stirred and to prevent the formation of lumps that could block the pipes downstream.

[0100] The lateral walls 46 are convergent with respect to each other so that the cement agglomerate, when discharged from the first mixer 13, converges toward the bottom wall 47 and then to the second mixer 15.

[0101] The second mixer 15 comprises a shaft 48 to which spiral shaped bladings 49 are solidly associated. The spiral shaped bladings 49 are defined by a continuous shaped blade from its portion where it is attached to the shaft 48 to its tip.

[0102] Longitudinal blades 50 are associated to the spiral shaped bladings 49, and extend parallel to the axis of the shaft 48 and are disposed between one spiral and the subsequent one. The blades 50 have the function of increasing the stirring effect to which the cement agglomerate is subjected.

[0103] The shaft 48 is made to rotate by a drive member 51 (fig. 2), possibly by means of reduction devices.

[0104] One of the lateral walls 46 is provided with an aperture 53 that provides to convey the cement agglomerate toward the pumping device 16.

[0105] The pumping device 16 in this case comprises a screw pump which in this case is made to rotate by the same shaft 48 that makes the second mixer 15 rotate.

[0106] More specifically the screw pump comprises a rotation shaft 57 associated to the shaft 48 of the second mixer 15 by means of a joint element 58.

[0107] At exit from the screw pump an attachment portion 55 is provided, to which are connected the tubes through which the cement agglomerate is pumped to convey it to the laying zone.

[0108] A measuring device 56 (fig. 3) is associated to the second hopper 45, to measure the level of the material contained therein.

[0109] When a maximum level of material is reached in the second hopper 45, the measuring device 56 commands the first mixer 13 to stop, to prevent the material from spilling out.

[0110] The apparatus 10 for the production of a cement agglomerate according to the present invention functions as follows.

[0111] The powdered cement is loaded through the first loading hopper 12. The first bladings 26 feed the cement to the aperture 31 and break up any lumps that may be present.

[0112] The powdered cement is transferred to the second section 23 of the first mixer 13 in which the water and foam are added in the desired quantities to determine the desired density and consistency of the cement agglomerate to be obtained.

[0113] Subsequently the cement agglomerate obtained is discharged, through the discharge aperture 43, into the second hopper 45.

[0114] The second mixer 15 further homogenizes the cement agglomerate generated in the first mixer 13, preventing problems of lumps in the concrete which could compromise the functioning of the screw pump and also obstruct the tubes that are associated to the attachment portion 55.

[0115] When the second mixer 45 is activated the pumping device 16 is also activated, and therefore the screw pump, to pump the cement agglomerate to the laying zone.

[0116] It is clear that modifications and/or additions of parts may be made to the apparatus for the production of cement agglomerate and the corresponding method as described heretofore, without departing from the field and scope of the present invention.

[0117] It is also clear that, although the present invention has been described with reference to some specific examples, a person of skill in the art shall certainly be able to achieve many other equivalent forms of apparatus for the production of cement agglomerate and the corresponding method, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby.

Claims

1. Apparatus for the production of a cement agglomerate, comprising first containing means (12) into which raw materials constituting at least part of said cement agglomerate are loaded, a first mixer (13) to mix said raw materials with at least a liquid substance, such as water, said liquid substance being introduced into said first mixer (13) by introduction means (37, 39), a second mixer (15) associated with second containing means (45) to remix the cement agglomerate obtained from said first mixer (13), and discharge means (16) being provided to make said cement agglomerate available for use, characterized in that said first mixer (13) is provided with at least a first mixing section (21), disposed in proximity to said first containing means (12), and a second mixing section (23) disposed in proximity to said introduction means (37, 39), said first (21) and second (23) section each being configured to respectively mix said raw materials and said cement agglomerate, and in that said second section (23) is provided with a blading (128) having at least a spiral shaped blade (129) attached to a rotation shaft (25) and kept distanced from the latter to define an interspace (131) between the spiral shaped blade (129) and the rotation shaft (25) for the passage of the raw materials.

2. Apparatus as in claim 1, characterized in that the spiral shaped blade (129) is attached to the rotation shaft (25) by means of connection elements (130).

3. Apparatus as in any claim hereinbefore, characterized in that the spiral shaped blade (129) has a length (L), in the radial direction, comprised between 0.75 and 0.95, preferably between 0.80 and 0.90, even more preferably about 0.85 with respect to the size (G) of the interspace (131).

4. Apparatus as in any claim hereinbefore, characterized in that the spiral shaped blade (129) has an angle of inclination of the spiral (β) comprised between 45° and 65°, preferably between 50° and 60°, even more preferably between 55° and 59°.

5. Apparatus as in any claim hereinbefore, characterized in that said second section (23) is provided with a plurality of spiral shaped blades (129) attached to said rotation shaft (25) one after the other and angularly staggered.

6. Apparatus as in any claim hereinbefore, characterized in that said rotation shaft (25) in said second section (23) is provided with a plurality of auxiliary blades (132) attached to said rotation shaft (25) and each extending in a radial direction.

7. Apparatus as in any claim hereinbefore, characterized in that between the first section (21) and the second section (23) an intermediate section (22) is interposed to transfer the raw materials from the first section (21) to the second section (23).

8. Apparatus as in claim 7, characterized in that the rotation shaft (25) extends longitudinally through the first section (21), the second section (23) and the intermediate section (22) and is suitable to support respective bladings (26, 27, 129, 132) in each of these.

9. Apparatus as in claim 8, characterized in that said intermediate section (22) is provided with bladings (27) conformed as a spiral to separate said first section (21) from said second section (23) and to prevent a reflux of material from the latter toward the first section (21).

10. Apparatus as in any claim hereinbefore, characterized in that said second section (23) comprises a pipe (33) in which said rotation shaft (25) and said spiral shaped blade (129) are housed.

11. Apparatus as in any claim hereinbefore, characterized in that said introduction means comprise at least a first pumping device (37) and a second pumping device (39) provided to introduce respectively water and foam into said second section (23) in order to lighten said cement agglomerate.

12. Apparatus as in any claim hereinbefore, characterized in that the said second mixer (15) comprises a first shaft (48) to which spiral bladings (49) are solidly associated, in that said discharge means comprise a pumping device (16) provided with a second shaft (57) solid with the first shaft (48), and in that a single actuation member (51) is provided to actuate the second mixer and the pumping device (16).

13. Apparatus as in any claim hereinbefore, characterized in that the first containing means (12), the first mixer (13), the introduction means (37, 39), the second (15) mixer and the discharge means (16) are grouped together in a single unit.

14. Method to produce a cement agglomerate, comprising at least a first step of loading raw materials constituting said cement agglomerate in first containing means (12), a second mixing step which provides a first sub-step of mixing said raw materials at least with a liquid substance such as water introduced by means of introduction means (37, 39), and a second mixing sub-step to mix the cement agglomerate obtained from the first mixer (13) before making it available for use, characterized in that said first sub-step provides a first mixing of said raw materials in said first containing means (12), and a subsequent mixing of said raw materials at least with the liquid substance, and in that said subsequent mixing is carried out by means of a blading (128) with at least a spiral shaped blade (129) attached to a rotation shaft (25) and kept distanced from the latter to define an interspace (131) for the passage of the raw materials between the spiral shaped blade (129) and the rotation shaft (25).

15. Method as in claim 14, characterized in that during said first sub-step at least water and foam are mixed with said raw materials in order to lighten said cement agglomerate.

Drawing