FR2788260A1 - Vibrating helicoidal lift for transporting bulk products at temperature different to ambient, comprises helical channel wrapped around central shaft, and vibrating base - Google Patents

Abstract

The lift has at least one helical channel (2) wrapped around a central shaft (1) and a vibrating base (3) supporting the assembly. The central shaft has a polygonal section with certain faces (6) receiving support braces (5) for the helical channel which are deformable in the YY' direction. The polygonal shaft has five to ten sides. The braces have a circular section and are made of the same material as the channel to which they are fixed. The coils of the channel are metallic, separated from each other, with a closed section and under a given electrical voltage which creates a heating effect inside the channel to heat the products. The braces are fixed to the central shaft and insulated from it by an insulating sole-plate (8). The faces of the shaft receiving the braces are concave or convex at ambient temperature and flat when the device is at the operating temperature above or below ambient temperature. The vibrating base has two out of balance motors (4) placed diametrically opposite relative to the central vertical axis XX' of the shaft and are mounted on supports which can position the motors at different angles of inclination relative to the XX' axis.

Description

Vibrating helical lifting device for the transport of products in

  The present invention relates to a vibrating helical lifting device for the transport of bulk products and undergoing a

heat treatment.

  The technical sector of the invention is that of making shaker conveyors with helical channels to allow the

  treatment of particles subjected to said vibrations of the transporter.

  The main application of the invention is the production of heat treatment devices continuously, of pulverulent products in particular in the food sector such as for sterilizing, pasteurizing, roasting (coffee, spices ...) but also in other industrial fields such as chemical, pharmaceutical ... and for solid products in particles of small particle size

  less than a few centimeters and which are said to be "loose".

  Numerous devices and methods are known for the treatment of solid particles which are mounted in at least one ramp or channel or tube or vibrating helical coil to subject them over a large part of their path inside said ramp or channel or ... at different temperatures between twenty and a thousand degrees Celcius with the additional possibility of bringing them into contact with

at least one fluid such as a gas.

  We can cite for example the patent application FR 2 634 187 of 12/07/88 entitled "vibrating conveyor" describing a helical ramp having a particular cross section, or the patent application FR 2 683 896 of 15/11/91 entitled "apparatus for the high temperature heat treatment of a divided solid body in which the helical product circulation channel is hollowed out in a block of

refractory material.

  More recently, mention may also be made of patent FR 2 701 861 filed on 02/26/93 entitled "Heat treatment of particles

  catalyst and absorbent solids in the presence of fluid in a vibrating helical coil ", according to which the heating of at least one step of the coil is effected by the Joule effect.

  Reference may be made to these various documents of the prior art to understand the operation of such devices and the various processing methods which they make it possible to implement without it being necessary to recall this known information, in the present

description;

  All these vibrating helical elevators, thus used as transporters of pulverulent products, or simply of small particle size, in bulk and which are subjected to heat treatment, suffer from serious problems related to their structure: in fact the dilations of the helical channel, due to the heat treatment which increases or decreases its temperature, has the result of generating high mechanical stresses at the level of this channel as well as on the systems for fixing it to the central drum and on the central drum itself; these constraints are all the higher as the central drum is often kept at a temperature different from that of the canal

  helical. The result of these constraints can be the breakage of the device.

  The problem is thus to be able to manufacture devices capable of carrying out any type of heat treatment according to the methods known to date such as those described in the prior art above, but also according to any other new method, and comprising at least one ramp or helical channel winding around a central drum, and a vibrating base supporting the assembly, and for which the mechanical stresses generated by the heat treatment do not induce a risk of rupture in the assembly of the device especially when it is vibrated; which vibrations must be adaptable to any type of treatment and to the products treated; in the case of hot heat treatment, the necessary heat supply which can be provided by the Joule effect as described in the patent application FR

2,701,861 cited above.

  One solution to the problem posed is a vibrating helical lifting device for the transport of bulk products at a temperature different from the ambient temperature comprising at least one helical channel winding around a central drum and a vibrating base supporting the assembly, in which said central barrel is of polygonal section, some of the faces of which receive support struts of said helical ramp and are deformable in the direction of these struts. In a preferred embodiment, the turns of said helical ramp are metallic, separated from each other, of closed section, and directly subjected to a given electrical voltage which induces a current which creates a thermal effect inside the channel,

  heating said products which are transported there.

  According to a specific embodiment, the faces receiving the spacers are deformed - either recessed towards the inside of the barrel at room temperature, and are flat when the device is at operating temperature above room temperature; - either curved towards the outside of the barrel at room temperature, and its flat when the device is at operating temperature

  below room temperature ..

  The result is new vibrating helical lifting devices for the transport of bulk products undergoing heat treatment, which respond to the problem posed since their structure is thus able to absorb the thermal stresses generated by their temperature rise: according to the present invention, indeed a structure which is rigid enough to transmit vibrations effectively from the vibrating base of the device to the coil or helical channel while allowing the induced expansions

  by the effects of temperature without risk of breaking the assembly.

  We could cite other advantages to the present invention but those cited above already show enough to prove the

  novelty and interest. The description and the figures below represent

  examples of embodiment of the invention but have no limiting character: other embodiments are possible within the scope and scope of this invention in particular by changing the number of faces of the polygon constituting the section of the central barrel, or by adapting any other specific device linked to the hot or cold heat treatment process, or other, which we want to apply to

  products transported in said helical channel.

  Figure 1 is a side view of a lifting device according to the invention.

  Figure 2 is a top view of the apparatus according to Figure 1.

  FIG. 3 represents on the one hand the same top view as that of FIG. 2, and on the other hand in dotted lines the position of the different parts of the lifting device once brought to operating temperature from a temperature position ambient

  corresponding to that of figure 2.

  Figure 4 is a top view of the same lifting device as that of Figure 1, at room temperature, according to a preferred embodiment according to the invention allowing when it is brought to temperature to position the elements constituting the device

  as shown in Figure 2.

  Figure 5 is a perspective view of part of the device according to the invention showing the method of fixing by spacer of the

  helical coil of the lifting device.

  Figure 6 is an exploded perspective view of a method of fixing the unbalance motors to put a device according

the invention in vibration.

  In a known manner, the vibrating helical lifting device for transporting bulk products comprises at least one closed helical ramp or channel 2 winding around a central drum 1 and a

  vibrating base 3 supporting the assembly.

  s According to the present invention, said central barrel is preferably cylindrical and of polygonal section: some of its faces 6 receive spacers 5 supports of said helical ramp 2 and are deformable in the direction YY 'of these spacers, that is to say perpendicular to the plane defined by their edges 8 common to two

adjacent faces ..

  The number of faces or sides of said polygon must be large enough so that these faces 6 are close enough "d" to the turns constituting said helical ramp 2 so that the spacers 5 are short enough but on the other hand this number of faces must not be too large otherwise the polygonal section would approach the shape of a circle and each face would be too narrow to allow deformation in the direction of the spacers it would receive; this is the case for the barrels of current devices whose section being a circle gives great rigidity to the structure, which is sought to transmit vibrations, but whose surface is then punched and even able to be torn, by the spacers, due to the different expansions of the various elements during the rise or respectively fall in temperature of the lifting device. Thus the section of the central shaft 1 is preferably a polygon of 5 to 10 sides and

  preferably 8 as shown in the accompanying figures.

  In the case where the temperature setting for a hot heat treatment is ensured by the electrical tensioning of the turns of said helical channel 2, which are metallic, of closed section and separated from each other, then giving off the necessary heat by effect Joule, said spacers 5 being fixed to the central barrel 1 can be isolated therefrom by a sole 8 of electrical insulating material interposed between the clip 9 in the form of a flange of said spacers 5 and the face 6 of barrel 1 receiving these, the fastening systems 10 of said plate / flange 9 with the insulating sole 8 and the face 6 ensuring themselves

  good electrical insulation by any known means.

  In all cases, said spacers 5 are preferably of circular section and made of the same material as the turns of the helical channel 2 on which they are secured such as by welding.

if the assembly is metallic.

  As previously indicated, the barrel 1 being at a different temperature, either lower or higher, than the helical ramp 2 and because of its shape and dimensions, its expansion or contraction is less than that of the helical ramp or channel, which induces all the more deformation towards the outside or respectively the inside of the faces 6 supporting the spacers 5, as shown in FIG. 3 in the event of a rise in temperature, if in the rest position at room temperature, said faces 6 are planes as shown on the

figure 2.

  To allow continuous operation at high or on the contrary low temperature with a minimum of deformation of said faces 6 relative to the flat surface defined by their edges 8, these faces receiving the spacers 5 are preferably deformed respectively: inside the barrel 1 at ambient temperature when this is lower than the operating temperature, as shown in FIG. 4, - is curved towards the outside of the barrel 1 at ambient temperature when the latter is above the temperature - and in all cases they are flat when the device is at operating temperature such as according to the arrangement in FIG. 2: such an assembly pre-stresses the faces 6 of the central barrel 1 when the appliance is not in operation with a degree of prestressing calculated according to the operating temperature of the device, so that in operation, the faces 6 s have in planar "rest" position without mechanical stress due to thermal expansion or contraction which reinforces the rigidity of the assembly to transmit vibrations.5 Thus, the two parameters necessary for the operation of the apparatus are reconciled, namely that on the one hand, the barrel wall must be sufficiently "flexible" to absorb the expansion of the coil 2 while being rigid enough to transmit homogeneous vibrations to the entire structure by the unbalanced vibration motors 4: this necessitates keeping torsional and vertical rigidity of the entire structure. In addition, the helical channel itself 2 is not subjected to any constraint because the support spacers 5 only follow its expansion or contraction without being retained by the faces 6 of the barrel 1: this also allows these spacers to be fixed on said was by a sole made of electrical insulating materials which in general are of low resistance and cannot be used without risk of breakage in other modes

  of realization than those of the present invention.

  Also due, among other things, to this absence of mechanical stress in operation, such a device according to the invention can undergo any type of vibration: also the vibrating base 3 which comprises, in known manner, at least two unbalanced motors 4 arranged diametrically opposite by relative to the vertical central axis XX ′ of the barrel 1 supports these thanks to an assembly on supports 7, 11, 13 which according to the present invention, as described in more detail by way of preferred exemplary embodiments below , are able to position said motors according to different angles of inclination from 0 to 360 relative to said axis XX ': it is thus possible to adapt the vertical component of

  vibrations at the transport speed and at the desired exchange coefficient.

  Said mounting supports for each unbalanced motor 4 may comprise, according to the representation in FIG. 6, a first plate 71 on which said motor 4 is fixed, an orientable support plate 72 against which the first plate 71 is pressed (but in other embodiments, there could be only one plate 7, carrying the motor 4), and an adjustable plate 73 also 5 and secured to the previous by any connecting means, such as by bolts passing through the orifices 14 provided for this purpose: these two orientable plates 72, 73 are arranged on either side of a collar or flange 13 fixed firmly, such as by welding, to a connecting tube 11 connecting the two motorized supports 4 arranged10 diametrically and opposite with respect to the axis XX 'of the barrel 1 and of the vibrating base 3, the latter further comprising internal reinforcements 12 and being secured to said connecting tube 11. It is thus possible to nter, by rotation of the integral unit with unbalance motors and plate 7 around the axis HH 'of the cylindrical connecting tube of revolution 11, the axis YY' of rotation of the unbalance motors 4 at any desired angle from 0 to 360 with respect to the XX 'axis,

  and block each motor assembly in the desired position by tightening the plates 7 on either side of the flange 13 which they sandwich.

Claims (8)

  1. Vibrating helical lifting device for transporting bulk products at a temperature different from that of the ambient medium comprising at least one helical channel (2) winding around a central drum (1) and a vibrating base (3) supporting the assembly, characterized in that said central barrel (1) is of polygonal section, certain faces (6) of which receive spacers (5) which support said helical channel (2) and are deformable in the direction YY 'of these spacers.   2. Device according to claim 1 characterized in that the section   of the central shaft (1) is a polygon of five to ten sides.   3. Device according to any one of claims 1 to 2 characterized   in that said spacers (5) are of circular section made of the same material as the turns of the helical channel (2) on   which they are united.   4. Device according to any one of claims 1 to 3 characterized   in that the turns of said helical channel (2) are metallic, separated from each other, of closed section, and directly subjected to a given electrical voltage which creates a thermal effect at   the interior of said channel (2) heating said products.   5. Device according to claim 4 characterized in that said spacers (5) are fixed to the central shaft (1) and isolated from it by an insulating material sole.   6. Device according to any one of claims 1 to 5 characterized   in that the faces (6) receiving the spacers (5) are hollow deformed towards the inside of the barrel (1) at room temperature and are flat when the device is at operating temperature   higher than room temperature.   7. Device according to any one of claims 1 to 3 characterized   in that the faces (6) receiving the spacers (5) are curved towards the outside of the barrel (1) at room temperature and are flat when the device is at an operating temperature below room temperature   8. Device according to any one of claims 1 to 7 characterized   in that the vibrating base (3) comprises at least two unbalanced motors (4), arranged diametrically opposite with respect to the central vertical axis XX 'of the barrel (1) and are mounted on supports (7, 11, 13 ) able to position said motors at different angles   tilt relative to said axis XX '.