Abstract:
The invention relates to a method for disposing of the washing liquid in a machine for washing items and the washing machine that implements the method. The machine comprises a chamber for washing the items, means for supporting at least one item in the washing chamber, means for storing the washing liquid, means for bringing the washing liquid into contact with the item to be washed, and means for eliminating the washing liquid from the machine. According to the method, to eliminate the washing liquid from the machine, the washing liquid is evaporated, thus reducing the volume of liquid to be eliminated.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to the washing machine sector and, in particular, to the problem of disposing of the used washing liquid. 
     Machines for washing components, in particular metal components for industrial use, are currently known, comprising a supporting frame which defines a tank or washing chamber and a mobile lid that can be opened and closed to allow insertion of the components in the tank, support means for the components in the tank and means which spray water and detergents dissolved in said water onto the components. 
     In such known washing machines the water is stored in the bottom of the tank or in a separate tank and repeatedly recirculated over the components. Thus, after a given number of washing cycles, despite the presence of filters which attempt to purify the washing water, said water becomes overloaded with washing residues, such as dust, grease, metal chippings and various residues present on the components before washing. When the water contains an excessive level of residues—for example every 15-30 days—it is substituted with clean water in which fresh detergent is dissolved. The remaining waste water contains a high level of pollutants and disposing of it is problematic and expensive. Companies which carry out this type of washing must install special chemical-physical purifiers outside the facility in order to subject the waste water to costly purification processes before disposing of it in the sewer network. If they are not equipped with such purification plant, they must acquire storage tanks for the temporary storage of the waste water, which must subsequently be transported to purifiers located at a distance from the working facility. Such waste water purification operations are expensive and inconvenient. 
     SUMMARY OF THE INVENTION 
     The present invention, in accordance with claim  1 , provides a method for disposing of the washing liquid in a machine for washing items, said machine comprising a chamber for washing the items, support means for at least one item in the washing chamber, means for the storage of a given volume of the washing liquid, means for bringing the washing liquid into contact with the item to be washed, and means for eliminating the washing liquid from the machine, characterized in that to eliminate the washing liquid from the machine, the liquid is at least partially evaporated, in order to reduce the volume of liquid to be eliminated. 
     The present invention also relates to a washing machine which implements the method according to the present invention. 
     The secondary claims refer to preferred embodiments. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Further characteristics and advantages of the invention are apparent from the detailed description which follows, with reference to the accompanying drawings, which illustrate preferred embodiments invention without restricting the scope of the invention and in which: 
     FIG. 1 is a schematic cross-section of a first preferred embodiment of the washing machine which implements the method according to the present invention; 
     FIG. 2 is a schematic cross-section of a second preferred embodiment of the washing machine which implements the method according to the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 illustrates a first preferred embodiment of the machine according to the present invention. The machine  10  for washing items comprises a supporting frame  12 , with feet  8 ,  9  which rest on the floor, defining a chamber  14  in which the items to be washed are housed by means of outer side walls, only walls  109 ,  110  and  111  illustrated in FIG. 1, a base wall  11  and a mobile upper wall  15 , defining a mobile lid, hinged to the wall  110  at  113 . 
     The washing machine  10  also comprises means which support at least one item  18 , in the form of a basket or support surface  16  located within the washing chamber  14  and rotated by a suitable motor  116  by means of a suitable transmission system, schematically illustrated using dashes and dots and labeled  117  in FIG.  1 . 
     In the washing machine disclosed, the washing liquid (labeled with the numeral  20 ) is stored in a lower compartment or tank  14 ′ in the chamber  14 , and to bring the washing liquid into contact with the item to be washed, spray nozzles  21  are envisaged on the pipes  22 , located around the support for the item  18  to be washed. In a further embodiment, the item to be washed may be brought into contact with the liquid by immersing it directly in the latter rather than using a spray system. 
     In the machine disclosed, the washing liquid, preferably water and detergent and any other washing agents, is recirculated several times over the items to be washed and is used in several washing cycles to wash different components. After a given number of washing cycles, when the liquid is too dirty due to residues removed from the components washed—said residues, for example, comprising various substances present on the components, such as greasy or oily substances, dust, metal chippings and other substances—the used washing water is eliminated from the machine and substituted with fresh, clean washing water. 
     According to the present invention, to allow the washing liquid to be eliminated from the machine  10 , means  26  are envisaged for evaporating, at least partially, said washing liquid  20 , so as to at least partially reduce the quantity or volume of liquid to be removed from the chamber, for example, through the lower tap  27 . 
     Said means for evaporating the liquid are a heating element  26  which heats the liquid and can also be used at a lower operating temperature to heat the liquid during the normal component washing stages. Means for evaporating the washing liquid other than the electrical heating element may also be used for the present invention. 
     The present machine also comprises suitable means for controlling said means  26  which evaporate the washing liquid, comprising a control unit  28  electrically connected to the heating element  26  and a control knob  30  which allows said evaporation stage to be started. 
     In accordance with a preferred control method, the means  26  for evaporating the washing liquid  20  are left on at least until all of the washing liquid has substantially evaporated. 
     To implement the preferred method, the control knob  30  can be used to start the evaporation stage, for example, at night, outside of normal working hours, and the heating element left on until the start of the next shift. 
     In this case, the heating element is of the type which operates without causing any damage, even when the chamber is empty, that is to say, in the absence of water to be heated. This guarantees the almost total elimination of the washing water and a “dry” residue with greatly reduced volume is obtained, allowing easy treatment of the residues. 
     As indicated, the storage compartment  14 ′ for the washing liquid extends below the washing chamber  14  and has a base wall  13  and outer side walls, of which only walls  149 ,  151 ,  152  are illustrated in FIG.  1 . 
     The top of said compartment  14 ′ opens into the chamber  14 , from which it is separated by a removable wall or panel  11 ′ with a central trap filter  29  through which the liquid  20  sprayed onto the item descends into the compartment  14 ′. 
     The present machine also comprises means  32  for recirculating the liquid  20  from the storage compartment  14 ′ to the sprayers  21 , said means comprising a recirculating pump  33  with an intake pipe  34  whose inlet, fitted with a filter  36 , is located in the lower compartment  14 ′ which stores the washing liquid, and a delivery pipe  38  directly connected to the pipes  22  of the sprayers  21 . 
     Moreover, as indicated, in order to completely evaporate the used washing liquid, the liquid evaporation means  26  are located close to the base  13  of said lower liquid storage compartment  14 ′. 
     To improve the evaporation cycle, means  40  are envisaged to allow the discharge of the vapor produced by the evaporation of the washing liquid  20  within the chamber  14 . 
     Said means for the discharge of the washing liquid  20  vapor take the form of a centrifugal extractor  40  which draws the vapor through an opening  42  in the side wall  110  of the chamber  14  and, through a pipe  44 , which may be fitted with filters for the vapor, directs it to the outside of the building in which the machine is installed. The vapor extracted by the extractor could also be condensed in a separate condensation tank  70 , as illustrated in FIG.  1 . 
     As indicated, the extractor means for the vapor produced are advantageously activated and controlled by the means  28  and  30  which control the heating element  26 . 
     According to the present embodiment means  46  are also envisaged for collecting and supporting the solid or pasty residue which remains after the washing liquid has evaporated. 
     Said means  46  for collection of the residue are a bag whose lower part  48  is at the base  13  of the liquid storage compartment  14 ′. The side  50  of the residue collection bag extends over at least part of the side walls of the compartment  14 ′. 
     The collection bag  46  extends alongside the heating means  26 , which are covered by a protective cage  31  to prevent contact with the bag  46 . 
     In order to allow the liquid to make contact with the heating element  26 , the bag  46  is made of a material which is permeable or porous, allowing the passage of the washing liquid, for example a fabric such as cotton or others, designed to filter the liquid. 
     As indicated, the inlet  36  of the washing liquid recirculating means is located above the collection means  46 . 
     The bag  46  can be extracted or removed from the machine, so that it can be substituted with a new bag for the residues. 
     Means for supporting the collection means  46  are envisaged, in the form of a quadrangular bracket  52  which, thanks to projections  54  can be attached to or removed from the lower compartment  14 ′ inside the chamber  14 . The bag  46  is fixed to the bracket  52  in such a way that it may be removed, allowing easy substitution. 
     The bag is removed by the operator, who reaches through the upper opening, of the chamber normally closed with the lid  15 , and, after removing the mobile base wall  11 ′, lifts the bracket  52  with the solid residues held inside the bag  48 . 
     FIG. 2 illustrates a second preferred embodiment of the washing machine according to the present invention. In FIG. 2, illustrating the second preferred embodiment of the machine, the elements similar to those in the first preferred embodiment are labeled using the same numerals as in the previous figure and, so that the present description is not too lengthy, are not described again. 
     The second preferred embodiment differs from the first preferred embodiment in that, at the base  13  of the compartment  14 ′, below said first means  46  for collection of the residues, there are second means  202  for collection of the residues, which pass across said first collection means  46 . 
     Said second collection means are a bag  202 , made of a plastic material impermeable to the liquid, supported by a quadrangular supporting bracket  204  which can be attached to projections  206  substantially at the base  13  of the compartment  14 ′ and can be detached from said projections to allow the removal and substitution of the plastic bag  202  following removal of the upper bag  46 . 
     The second preferred embodiment also envisages that the part  50  of the porous bag  46  extends completely above the protective cage  31  over the heating element  26 . 
     In the preferred embodiments illustrated, the washing chamber  14  is quadrangular in shape and the compartment or tank  14 ′ is also quadrangular, although shorter, leaving a lateral space below the chamber  14  so that the various means used to drive the machine can be housed there. However, the compartment  14 ′ could have a different shape to the quadrangular shape illustrated, for example, cylindrical, conical, or other shapes. 
     The machine referred to in the present invention is preferably used to wash metal components for industrial use. However, it could be adapted to make it suitable for washing any type of item, such as pans, crockery, fabrics and others. 
     The washing machine could also use and evaporate solvent washing liquids other than the water described herein.