Patent Publication Number: US-2018029090-A1

Title: Method for cleaning die plates for the production of pasta or snacks and machine for its execution

Description:
TECHNICAL FIELD 
     The present disclosure relates to a method for cleaning die plates for the production of pasta or snacks and to a machine for its execution. 
     BACKGROUND 
     Machines are known for carrying out the cleaning of die plates for the production of pasta or snacks. Substantially, all pasta factories or makers of snacks have at least one of these machines which they use to clean die plates before returning them to storage or reusing them for a new production cycle. 
     These machines, which in the sector are known as “die plate washers”, consist substantially of a closed volume provided with special supports that are adapted to support the die plate during the step of washing. Removal of the residue of mixture present inside the holes of the die plates at the end of the production cycle is done by way of the mechanical action of water jets generated by an adapted pump that supplies a series of three or more nozzles. According to requirements, these machines are provided with systems that perform the movement of the die plate, or of the nozzles dispensing the jets of water under pressure, or both, so that the jets can affect the entire drawing area when performing the washing thereof. 
     In less advanced contexts, in order to execute the washing of the die plates, ordinary high-pressure washers, with a wand, are also used. In this case, the movement of the nozzle to affect the entire drawing area, in order to achieve a satisfactory wash, is given over exclusively to the ability of the operator. 
     Cleaning die plates by means of the die plate washing machines currently on the market, like cleaning using high-pressure washers with a wand, entails the use of huge volumes of water which produce a sticky discharge that, by its nature, is difficult to dispose of This sticky discharge is the cause of unpleasant odors in the rooms used to wash the die plates. 
     Furthermore, the cleaning process causes the projection of fractions of this sticky discharge onto parts of the machine and of the equipment located nearby; such fractions of discharge, if not quickly removed, can cause the rapid deterioration of the machine and of the spattered equipment. 
     SUMMARY 
     The aim of the present disclosure is to solve the above mentioned problems, by devising a method and a machine that make it possible to reduce the quantity of sticky discharge deriving from the cleaning of die plates, thus reducing the problems associated with its disposal. 
     Within this aim, the disclosure provides a method and a machine that are capable of appreciably reducing the source of unpleasant odors and of dirt so as to obtain a substantial improvement of the environmental conditions in the places used to wash die plates. 
     The disclosure further provides a method and a machine that ensure a high efficacy of cleaning die plates even in die plates with work holes that are difficult to reach completely with jets of water under pressure. 
     The disclosure also provides a machine for cleaning die plates that is structurally simple, ensures a high reliability of operation, and can be produced at low cost. 
     The disclosure provides a method for cleaning die plates for the production of pasta or snacks including the following steps: 
     a first step, in which a working fluid is placed in contact with one of two end faces of a die plate to be cleaned; 
     a second step, in which the pressure of said working fluid is increased so as to force said working fluid to penetrate the holes of the die plate in order to push the residue of the mixture, present in said holes, so that it exits from the opposite end face of the die. 
     For the execution of the method according to the disclosure, preferably a machine for cleaning die plates for the production of pasta or snacks is used, the machine comprising: 
     a jacket that internally defines a chamber; 
     an opening which is defined in one of the walls of said chamber and can be coupled to a die plate to be cleaned which can be arranged so that one of its end faces is connected to the inside of said chamber; 
     means for introducing a working fluid into said chamber; 
     means adapted to increase the pressure of said working fluid in order to force it to pass through the holes of the die plate which are occupied by the mixture to be removed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further characteristics and advantages of the disclosure will become better apparent from the detailed description that follows of a preferred, but not exclusive, embodiment of the method according to the disclosure, as well as of a machine for its execution, which is illustrated for the purposes of non-limiting example in the accompanying drawings wherein: 
         FIG. 1  schematically illustrates a machine for executing the method according to the disclosure, in an axially cross-sectional view at the start of the method; and 
         FIG. 2  schematically illustrates the machine of  FIG. 1  at the end of the method. 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     With reference to the figures, a machine for executing the method according to the disclosure, generally designated by the reference numeral  1 , comprises a jacket  2  which defines, internally, a substantially cylindrical chamber  3 . 
     In one of the walls that delimit the chamber  3 , an opening  4  is defined that can be coupled with a die plate  5  to be cleaned so that one of the two end faces of the die plate  5  is connected to the inside of the chamber  3 . 
     The machine according to the disclosure comprises means  6  of introducing a working fluid into the chamber  3  and means adapted to increase the pressure  7  of the working fluid so as to force it to pass through the holes  8  of the die plate  5  which are occupied by the mixture  9  to be removed. 
     Conveniently, the working fluid is constituted by a shear thickening fluid and that is to say by a non-Newtonian fluid the density of which increases as the speed of deformation increases. 
     This shear thickening fluid, in consideration of the fact that it is used in the food sector, is preferably constituted by a mixture of starch or potato starch and water. 
     In more detail, the chamber  3  is substantially cylindrical and the opening  4 , which is intended to receive the die plate  5  to be subjected to cleaning, is defined at one of the two end faces of the chamber  3 . At the opening  4  intended to receive the die plate  5 , there are means  10  of retaining the die plate  5  so as to close the opening  4  in contrast with the action exerted by the working fluid. 
     The means  10  of retaining the die plate  5  comprise a ring  11  which is held in place by a clamping band  12 . 
     The clamping band  12  engages with a flanging  13  defined at one axial end of the jacket  2  and with a flanging  14  of the ring  11  so as to adequately oppose the pressure exerted by the working fluid on the die plate  5 . 
     Preferably, the chamber  3  is delimited, on the opposite side from the opening  4  intended to be occupied by the die plate  5 , by a piston  15  which is arranged coaxially with the chamber  3 . 
     Substantially, the piston  15  subdivides the inside of the jacket  2  into two chambers, respectively: the chamber  3 , or first chamber, which is axially delimited by an end face of the jacket  2  in which the opening  4  intended to receive the die plate  5  is defined and by a face of the piston  15 , and a second chamber  16  which is axially delimited by the opposite face of the piston  15  and by the opposite end face of the jacket  2 . 
     The means adapted to increase the pressure  7  of the working fluid comprise means of pumping an actuation fluid under pressure into the second chamber  16 . 
     Preferably these pumping means can be constituted simply by a conventional pump  17 , for example a piston pump, a centrifugal pump, a gear pump or other type of pump. 
     The chamber  3  is connected to a duct  18  along which is arranged a valve  19  which can be opened in order to actuate the filling of the chamber  3  with the working fluid. 
     The machine is further provided with means  20  of moving the piston  15  away from the end face of the jacket  2  which is occupied by the die plate  5  at the end of the method, as will be better described hereinafter. 
     More specifically, the piston  15  is provided with a stem  21  which is connected to the face of the piston  15  which delimits the second chamber  16  and which exits from the opposite end face of the jacket  2  with respect to the end face intended to receive the die plate  5 . 
     The movement means  20  of the piston  15  can be constituted, as illustrated, by two or more fluid-operated actuation cylinders  22  which are mounted with their body on the jacket  2  and which are oriented with their axis parallel to the axis  3   a  of the chamber  3 . The fluid-operated actuation cylinders  22  are pivoted, with the end of the stem of their pistons, to a plate  23  which is fixed to the stem  21  of the piston  15 . 
     For the sake of completeness of the description it should be noted that, between the die plate  5  subjected to cleaning and the side walls of the chamber  3 , there is a sealing gasket  24 , just as there are sealing gaskets  25  between the stem  21  of the piston  15  and the jacket  2 . Alternatively, the seal between the die plate  5  and the jacket  2 , instead of by way of a radial gasket as illustrated, can be provided by way of an axial gasket conveniently forming the part of the jacket  2  that mates with the die plate  5 . 
     The jacket  2 , or preferably the clamping band  12 , can be supported by a trolley  26 . 
     In the embodiment shown, the chamber  3  is arranged with its axis  3   a  vertical, which appears to be the rationally most correct arrangement, but it can be oriented differently according to requirements. 
     Operation of the machine described above in carrying out the method according to the disclosure is the following. 
     Initially, the piston  15  is raised completely, as illustrated in  FIG. 1 , the chamber  3  is empty and the die plate  5  to be subjected to cleaning is coupled with the open lower end face of the chamber  3  and locked by way of the ring  11  and the clamping band  12 . 
     With the die plate  5  to be subjected to cleaning thus positioned, the chamber  3  is filled with the working fluid by way of opening the valve  19 . The air present inside the chamber  3  is progressively evacuated, for example through valves, which are conventional and not shown for the sake of simplicity. 
     Once the chamber  3  has been filled with the working fluid, the pump  17  is actuated and introduces an actuation fluid under pressure, for example water, into the second chamber  16  thus causing the descent of the piston  15  and therefore increasing the pressure of the working fluid which progressively penetrates all the holes  8  of the die plate  5 , propelling the mixture  9  contained in them outward until all the holes  8  of the die plate  5  are completely cleared, as illustrated in  FIG. 2 . 
     It should be noted that, since the working fluid is constituted preferably by a shear thickening fluid, if one or more holes  8  of the die plate  5  should be cleared of the mixture  9  before the others, at these holes  8  the fluid would undergo a rapid deformation and therefore its viscosity would increase considerably, braking its dispersion outward and therefore maintaining a pressure of the working fluid inside the chamber  3  which is such as to ensure the expulsion of the mixture  9  through the holes  8  of the die plate  5  that are still occluded. 
     At the end of the expulsion of the mixture  9  from the holes  8  of the die plate  5 , such holes  8  will be occupied by the working fluid which however is much less thick than the mixture  9  and therefore can be removed with great ease, for example with a jet of water. 
     After the removal of the die plate  5  from the machine, the piston  15 , by way of actuation of the fluid-operated actuation cylinders  22 , is lifted and returned to the initial position, while the actuation fluid is evacuated from the second chamber  16 , for example by way of a reverse operation of the pump  17 . 
     In the embodiment shown, the pressure of the working fluid in the chamber  3  is increased by way of the introduction of a fluid under pressure into the second chamber  16 ; however, the pressure of the working fluid in the chamber  3  could also be increased by mechanically actuating the piston  15 , or the piston  15  could be absent and the pressure of the working fluid could be increased directly by introducing the working fluid into the chamber  3  by way of a press, for example a screw press. 
     It should be noted that the method according to the disclosure makes it possible to perform the cleaning of die plates using a reduced quantity of water and especially by avoiding an excessive washout of the mixture removed. Thanks to this fact, the method according to the disclosure makes it possible to considerably reduce the quantity of sticky discharge deriving from the operation to clean the die plates compared to the techniques used currently. 
     In practice it has been found that the method and the machine according to the disclosure fully achieve the set aim and objects in that, by reducing the quantity of sticky discharge deriving from the cleaning of die plates, it reduces the problems associated with its disposal, avoids the projection of fractions of the waste deriving from cleaning, and reduces the unpleasant-smelling emissions, thus improving the environmental conditions in the rooms used for washing die plates. 
     In practice, the materials employed, except where otherwise specified above, as well as the dimensions, may be any according to requirements and to the state of the art.