Patent Publication Number: US-7213606-B2

Title: Valve device, a unit for unloading loose materials from a dispenser device to a user unit comprising the valve device and a method for unloading loose material from a dispenser device to a user unit

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates to a valve device, in particular a valve device which can be used in a unit for unloading loose material from a dispenser device to a user unit. 
   The device disclosed can be used in particular in the chemical and/or pharmaceutical industry and in all cases for unloading containers of loose material consisting of powders, granulated material, pellets, tablets, capsules or similar products. 
   Such containers are normally emptied at an unloading station and the material they contain is transferred to a collection tank connected, for example, to a user unit or machine which uses the loose material for subsequent processing. 
   In the above-mentioned unloading station, a supporting structure holds the collection tank at a level lower than that of the container, to allow container emptying by gravity. 
   Connecting means are used to transfer the material from the container to the tank, said connecting means consisting, for example, of a rigid cylindrical tube with a vertical axis, supporting an interchangeable tubular bag in which the loose material being processed flows. 
   Such connections must be substantially airtight, so that, as the powdered material passes through the tubular bag, the diffusion of powders in the surrounding environment is kept within extremely narrow limits. 
   The importance of the problem mentioned above increases when the substances handled are chemical substances or compounds that are not easily degradable in the environment and in some cases potentially toxic or harmful. 
   Moreover, obviously when switching from processing one material to processing another, the tubular bag must be substituted and the connection thoroughly cleaned. 
   At its upper end, the cylindrical tube normally has a ring-shaped body, or spacer, designed for connection to the container and airtight fixing of the upper end of the tubular bag. The lower outfeed end of the container is also fitted with a valve element designed to open or close the lower end. 
   Said valve element normally consists of a butterfly valve with a flat disk-shaped shutter element that rotates in both directions about a horizontal axis between a position in which the lower end of the container is closed, with the shutter lying in a substantially horizontal plane, and a position in which the lower end of the container is open, with the shutter lying in a substantially vertical plane, allowing the material to be unloaded from the container to the cylindrical tube. 
   Conventional unloading units, of the type described, are not fully satisfactory as regards the problems relative to pollution. They have the disadvantage that, during container emptying, the face of the disk-shaped element which faces the outside environment when the valve element is closed makes contact with the powdered material during unloading, when the disk-shaped element is in the vertical position. 
   Secondly, during removal of the container from the cylindrical tube, the upper end of the spacer, having also been in contact with the powdered material, is exposed to the surrounding environment. 
   Attempts were made to overcome the above-mentioned disadvantages with a solution that involved inserting a hopper of a substantially known type between the valve element of the container and the above-mentioned spacer connected to the tubular pipe, equipping the spacer with a butterfly valve so as to form a washing chamber between the inner surface of the hopper, the lower surface of the container outfeed valve and the upper surface of the valve located substantially at the spacer infeed. Moreover, in said case, the hopper must be suitably modified and equipped with internal washing nozzles. 
   When the loose material has been unloaded, the container valve and the spacer valve are closed and, before the container is separated from the pipe and from the spacer, the inside of the hopper is washed. 
   Said washing is carried out using directional nozzles giving onto the inner surface of the hopper, to clean the surfaces of the two valves which will be in contact with the outside environment. 
   However, the solution just described is not without disadvantages, which are mainly due to the considerable dimensions of the washing chamber, which make thorough washing of it difficult. 
   Moreover, the use of nozzles located on the side surface of the hopper does not guarantee thorough cleaning of the valves and in particular their central zone. 
   To overcome the problems relative to environmental pollution with reference to the normal unloading devices described above, another solution was developed, described in EP 1.043.252. 
   Said solution relates to an unloading unit in which the valve element for closing the container consists not of the above-mentioned single disk-shaped element, but of two disk-shaped closing elements positioned one over the other and releasably connected to one another. 
   More precisely, said valve element behaves for all practical purposes, as regards opening and closing operations, like the devices described above but, at the moment when the container is substituted, the above-mentioned closing elements positioned one over the other are detached from one another and whilst the first closes the outfeed end of the empty container, the second closes the upper end of the spacer, preventing contact between the above-mentioned contaminated parts and the outside environment, towards which the faces that were previously in contact with one another face. 
   In the case of said valve element, before the two closing elements are separated, they may be washed to eliminate powder residues that are inevitably deposited in the circular ring formed by the two closing elements. 
   To facilitate washing of such devices, versions were developed equipped with detachment means substantially designed to noticeably move the closing elements away from one another so that they leave an air space between them which promotes cleaning before definitive separation. 
   The latter devices are also not without disadvantages. 
   Firstly, the production of closing elements which fit together perfectly requires high precision mechanical machining involving operating difficulties and high costs. 
   Moreover, a device made in that way requires constant and extended periodic maintenance since it is so complex that it needs continuous attention. The result of this is periodic, inconvenient, inevitable system downtime. 
   Due to its complex construction, the device just described also has surfaces that hold onto the powders at the end of unloading which have a substantially irregular shape and, therefore, are difficult to wash. 
   Even when an air space is created between the two closing elements, the washing space remains limited and, as a result, cleaning is not thorough enough, since the action of the detergent fluids, normally dispensed by spray nozzles of the known type, is not effective enough. 
   SUMMARY OF THE INVENTION 
   The aim of the present invention is, therefore, to overcome the above-mentioned disadvantages by providing a valve device which can be easily and effectively washed. 
   Another aim of the present invention is to provide a valve device which guarantees thorough and deep cleaning of all of the surfaces which came into contact with the loose material unloaded from the dispenser device. 
   Yet another aim of the present invention is to provide a valve device whose use minimizes the risks of environmental pollution, particularly when the container and the pipe are separated. 
   The technical features of the present invention, in accordance with the above-mentioned aims, are set out in the claims herein, in particular claim  1  and preferably any of the claims directly or indirectly dependent on claim  1 . 
   The present invention also relates to a unit for unloading loose materials comprising the above-mentioned valve device and to a method for unloading loose materials using said unit. 
   There follows a description of a preferred embodiment of a valve device according to the present invention, by way of example and without limiting the scope for application. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The advantages of the present invention are more clearly illustrated in the detailed description which follows, with reference to the accompanying drawings, which illustrate a preferred embodiment of the invention without limiting the scope of the inventive concept, and in which: 
       FIG. 1  is a schematic side view of a unit for unloading loose materials according to the present invention; 
       FIG. 2  is a schematic side view, suitably interrupted, with some parts in cross-section, of the unit illustrated in  FIG. 1  in a first operating configuration; 
       FIG. 3  is a schematic side view, suitably interrupted, with some parts in cross-section, of the unit illustrated in  FIG. 1  in a different operating configuration to that illustrated in  FIG. 2 ; 
       FIG. 4  is a schematic view, partly in cross-section according to line III illustrated in  FIG. 3 , of the unit for unloading loose material according to the present invention; 
       FIG. 5  is a schematic side view, suitably interrupted, with some parts in cross-section, of the unit illustrated in  FIG. 1  in another operating configuration; 
       FIGS. 6 to 8  are three different schematic views of a detail of the device illustrated in the previous figures; 
       FIG. 9  is a schematic side view, suitably interrupted, with some parts in cross-section, of another embodiment of the device according to the present invention. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   With reference to the accompanying drawings, and in particular with reference to  FIGS. 1 to 5 , the numeral  1  denotes a valve device, in particular a valve device  1  applied to a unit  2  for unloading loose materials. 
   As illustrated in  FIGS. 2 ,  3  and  5  the device  1  comprises a pipe  3 , with a central axis A substantially coinciding with a unit  2  main direction D of extension. 
   The pipe  3  is formed by a first ring-shaped body  4 , coaxially connected to a second ring-shaped body  5 . Said ring-shaped elements  4  and  5  have respective outer profiles  4   a ,  4   b ,  5   a  and  5   b , suitably shaped for reciprocal  4   a – 5   a  connection, and for connection to the unit  2  for unloading loose materials. 
   The above-mentioned reciprocal  4   a – 5   a  connection is guaranteed by detachable coupling means, located at the opposite profiles  4   a  and  5   a , comprising a band  6  which has, as shown in  FIG. 4 , two half-parts joined by a ring  7  and a clamp screw  8 . 
   Advantageously, between the first and the second ring-shaped bodies  4 ,  5  a seal  9  is inserted, also preferably ring-shaped, designed to guarantee a sealed connection between the elements  4  and  5 . 
   The first and the second ring-shaped bodies  4  and  5  respectively support a first closing element  10  and a second closing element  11 . 
   The first closing element  10  has a radius R 1  and is mobile between a first position in which it leaves the pipe  3  open and a second position in which it seals the pipe closed. 
   The second closing element  11  has a radius R 2  and is mobile between a first position in which it leaves the pipe  3  open and a respective second position in which it seals the pipe closed. 
   In the preferred embodiment illustrated, the radii R 1  and R 2  are substantially equal. 
   The elements  10  and  11  lie, in their respective open positions, in planes substantially parallel with the above-mentioned axis A and, in their respective closed positions, in planes substantially perpendicular to the axis A. 
   In this text, with reference to the respective orientation of the closing elements  10  and  11 , the term horizontal means that the elements  10  and  11  lie in planes substantially perpendicular to the central axis A of the pipe  3 , and the term vertical means that the elements  10  and  11  lie in planes substantially parallel with the axis A. 
   In other alternative embodiments, not illustrated, the closing elements  10  and  11 , in their respective open and closed positions, may have any spatial orientation, depending on the user unit  3  in which they are used and according to the material with which they are designed to make contact. 
   It should be noticed that the first closing element  10  and the second closing element  11  are separated, when in their respective closed positions, by a distance slightly greater than their radius, to guarantee the possibility of separate opening of the elements  10  and  11 , as illustrated in  FIG. 5 . 
   With reference to  FIG. 9  which illustrates an alternative embodiment, the closing elements  10  and  11  are separated by a distance which is less than the radii R 1  and R 2 . In the latter case, the elements  10  and  11 , as better described below, must move simultaneously, since it is not possible to fully open only one of the elements  10  and  11 . 
   In an alternative embodiment, not illustrated, the elements  10  and  11  have different radii R 1  and R 2 . In this case, the distance between the closing elements  10 ,  11  must be greater than the largest of the two radii R 1 , R 2  to allow separate movement of the elements  10  and  11 . 
   With reference to the accompanying drawings from  2  to  5 , the elements  10  and  11  are respectively connected, by way of example only, to a mechanical actuator  12  and to a pneumatic actuator  13  which drive the movement of the elements  10  and  11 . 
   In embodiments not illustrated, said mechanical or pneumatic actuators  12  and  13  may also be fitted without distinction for one or for the other closing element  10 ,  11  or for both and there may be more than one actuator per closing element  10  and  11 , for example depending on the dimensions of the elements  10  and  11 . 
   The actuators  12  and  13  are controlled by a check and control unit U for their synchronized or separate movement. 
   In other words, the closing elements  10  and  11  may be opened simultaneously or independently of one another even according to their reciprocal positioning. 
   The device  1  also comprises a check sensor  14  for monitoring the position of the closing elements  10 ,  11  and, in particular, for verifying when the elements reach their respective closed or open positions. 
   The pipe  3  and the elements  10  and  11 , in the respective closed positions, form a chamber  15  which can be washed by washing means operating at the chamber  15 . 
   In particular with reference to  FIG. 9 , it may be seen that the closing elements  10  and  11  have respective surfaces  10   a ,  11   a  facing the inside of the chamber  15  which are smooth, that is to say, free of projections. 
     FIGS. 2 and 3  in particular show how the washing means comprise a washing part  16 , mobile between a first, operating configuration in which it is inserted in the chamber  15 , illustrated in  FIG. 3 , and a second, non-operating configuration in which it is at least partly outside the chamber  15 , illustrated in  FIG. 2 . In particular, in the preferred embodiment illustrated by way of example, the part  16  is completely outside the chamber  15  in the non-operating configuration. 
   Taking a more detailed look and with reference to  FIGS. 6 to 8 , the part  16  comprises an orbital washing head  17  supporting a pair of nozzles  18  for dispensing a washing fluid F. 
   In this text the term orbital refers to the fact that the nozzles  18  supported by the head  17  are mobile in space. 
   In particular, in the preferred embodiment illustrated by way of example, the head  17  rotates about a first axis of rotation A 1  substantially transversal, in particular perpendicular, to the central axis A of the pipe  3  and about a second axis A 2  transversal to the first axis A 1  and in particular perpendicular to it. 
   In the embodiment illustrated, although without in any way limiting the scope for application of the invention, the part  16  comprises an arm  19  supporting the orbital head  17  and having a main axis of extension B. The first axis of rotation A 1  substantially coincides with the main axis B of the arm  19 . 
   In particular, the head  17  is mobile according to a law of motion consisting of a first rotary movement about the first axis A 1  and of a second rotary movement about the second axis A 2 . 
   Again with reference to  FIGS. 6 to 8 , the head  18  is connected to the arm  19  by a bevel gear pair  40  consisting of a first bevel gear  41 , integral with the arm  19 , and a second bevel gear  42  integral with the head  18 . 
   The head  18  is connected in such a way that it can rotate idly to a supporting body  43  integral with a shaft  44 , coaxial with the arm  19 , which rotates, driven by motor means not illustrated, about the axis B. 
   Said configuration means that the head  17  can rotate about the axis A 1 , drawn by the supporting body  42 , whilst the meshing of the bevel gears  40  and  41  induces the rotary movement of the head  17  about the axis A 2 . 
   In alternative embodiments not illustrated, there may be any number of nozzles  18  of any type, according to the geometry of the chamber  15  and the material to be washed. Even the head  17  may be mobile according to any law of motion, designed to effectively direct the washing fluid F inside the chamber  15 . 
   Moreover, advantageously, the head  17  can be stably inserted in the chamber  15 . This positioning is achieved both with the washing part  16  extending stably inside the chamber  15 , and by fixing the head  17  on the inner surface of the chamber  15 . 
   In a preferred embodiment of the device disclosed not illustrated, the head  17  is housed inside a covering cap designed to facilitate head cleaning and prevent dirt deposits and the build up of materials between the elements located at the head  17 . 
   As illustrated in  FIGS. 2 ,  3  and  5 , the chamber  15  has an opening or entrance  20  close to which sealing means are operatively active, comprising a door  21 , mobile between a first, outer position in which the chamber  15  is sealed closed, when the part  16  is in the non-operating configuration, and a second, open position when the part  16  can pass through the opening  20 . 
   The sealing means also comprise a seal element  22 , located at the opening  20  to guarantee that the chamber  15  is sealed closed and to prevent the material unloaded through the device  1  from escaping. 
   It should also be noticed that in the embodiment illustrated, the opening  20  is made in the second ring-shaped body  5  but, advantageously, in embodiments not illustrated, it may be made in any position in the side surface of the pipe  3 . 
   At the opening  20  there is also a structure  23  which supports and receives the part  16 , comprising drive means M of the known type for moving the part  16 . 
   In particular with reference to  FIG. 4 , it should be noticed that the device  1  comprises drying means communicating with the chamber  15 , designed to dry the chamber  15  once it has been washed, if the fluid F is in the liquid state. Said means comprise a compressed air source  24  communicating with the inside of the chamber  15  through a channel  25 . 
   The device  1  also comprises a suction apparatus  26 , also communicating with the inside of the chamber  15  through the channel  25 , and together with the channel  25 , forming suction means designed to extract the washing fluid F from the chamber  15 . 
   The suction means are also designed to depressurize the chamber  15 , that is to say, to bring the pressure inside the chamber  15  to a value lower than the atmospheric pressure, at least during washing, to prevent any fluid F from escaping. 
   In alternative embodiments not illustrated, the suction apparatus  26  may be fluidly connected to the chamber  15  by a plurality of channels  25 . 
   Similarly, the drying means may comprise a plurality of channels, not illustrated, even separate from the channel  25  used for suction, communicating with the chamber  15 . The number and distribution of said channels, which are not illustrated, depends on the extent and shape of the chamber  15 . 
   The drying means may also comprise the same orbital head  17  that can be used to dispense compressed air, which may be hot, to dry the chamber  15 . 
   Advantageously, the suction means may also extract from the chamber  15  any loose material powder residues which may have been deposited during use of the device  1 , as described below. 
   In the unit  2  for unloading loose materials, the device  1 , as described, is inserted between a dispenser device  27  and a user unit  28  and, in particular, the first ring-shaped body  4  is connected, at the profile  4   b , to a device  27  outfeed  29  and the second ring-shaped body  5  is connected, at the profile  5   b , to an infeed end  30  of a tube  31  whose second end  32  is connected to the user unit  28 . Said connections are made with detachable coupling means similar to those previously described, that is to say, using a first band  116  and a second band  216  each made in two parts and joined by a respective ring and a respective clamp screw. 
   It should be noticed that, in alternative embodiments not illustrated, the device  1  and the unit  2  may not be fitted with the above-mentioned detachable coupling means, both between the ring-shaped bodies  4  and  5  and between the device  1  itself  2  and the rest of the unit  2 . In particular, said connections may be made by gravity, that is to say, by the pressure applied by the dispenser device  27  on the rest of the unit  2 , or by elastic means of the substantially known type. 
   In practice, to unload loose material from the dispenser device  27 , the device  27  itself, together with the first ring-shaped body  4  and the first closing element  10 , which blocks the device  27  outfeed  29 , is placed, using known methods, on the tube  31  closed by the second closing element  10  and is fixed to the second ring-shaped body  5 , therefore forming the chamber  15 . 
   If the unit  2  or the device  1  are positioned in a polluted or uncontrolled environment, the chamber  15  may be washed before unloading the material, to prevent pollution of the material itself. 
   Washing is preferably carried out after depressurizing the chamber  15  with the suction means. In particular, the washing part  16 , or rather the orbital head  16 , is inserted in the chamber  15 , and the chamber is cleaned. 
   After washing, preferably keeping the pressure inside the chamber  15  at a value lower than that of the atmospheric pressure, the chamber  15  is dried if the fluid F used is in the liquid state. 
   The elements  10  and  11  are then brought into the respective open positions (simultaneously or separately depending on the type of chamber) and the material is unloaded from the dispenser device  27  to the user device  28 . 
   When unloading is complete, after returning the elements  10  and  11  to their respective closed positions, the chamber  15  can be washed again, as described above, to eliminate any residues of the material unloaded from the walls of the chamber  15  and, in particular, from the surfaces of the elements  10  and  11 . 
   When this further washing is complete, the two ring-shaped elements  4  and  5  may be separated, that is to say, the dispenser device  27  may be separated from the tube  31 , without dispersing particles of the material dispensed into the outside environment, since the inner surfaces of the pipe  3  and of the closing elements  10  and  11  are clean. 
   It should be noticed that all of the washing and drying operations preferably take place at a pressure lower than the atmospheric pressure, to minimize the risk of the washing fluid escaping. 
   The invention fulfils the preset aims since the use of an orbital washing head inserted in the washing chamber guarantees thorough cleaning of every element forming the chamber and prevents both pollution of the material to be unloaded and pollution of the environment at the end of unloading. 
   The invention described is suitable for evident industrial applications and may be subject to modifications and variations without thereby departing from the scope of the inventive concept. Moreover, all of the details of the invention may be substituted with technically equivalent elements.