Abstract:
A barrier device for withholding odors released by a malodorous substance, particularly for purifying plants; the barrier device is provided with a plurality of atomizing nozzles for generating a layer of atomized liquid for covering the free upper surface of the malodorous substance.

Description:
PRIORITY CLAIM 
       [0001]    This application claims priority to PCT Application No. PCT/EP2005/055031 filed Oct. 5, 2005, which claims priority to Italian Patent Application No. TO2004A 000669 filed Oct. 5, 2004, which are incorporated herein by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    An embodiment of the present invention relates to a barrier device for withholding odors released by a malodorous substance, particularly for purifying systems. 
       BACKGROUND 
       [0003]    As it is known, in some treatment and purification steps of sludge and/or sewage, there is the need to abate the unpleasant odors which are released by the substances subjected to treatments and possible stirring actions. 
         [0004]    To fulfill this need, it is known to airtightly close the upper part of the tanks which contain the treated malodorous substances. 
         [0005]    However, the upper closing of the tanks may be unsatisfactory, because it is relatively complex to make and implies relatively high costs. Such drawbacks are mainly due to the fact that systems are generally necessary for extracting and filtering the gasses which are released by the malodorous substances contained in the tanks to prevent the pressure of the gasses from reaching high levels and creating explosion risks. 
         [0006]    Furthermore, in the known solutions, opening the tanks at their top, for example to access the inside for inspecting the substances contained visually and/or for taking possible samples of such substances to be analyzed, is rather long and complex. 
         [0007]    U.S. Pat. No. 5,861,096, which is incorporated by reference, discloses a system for controlling odor in industrial lagoons, including a plurality of nozzles adapted to sprinkle or spray a chemically active water solution onto the free surface of the lagoon. 
         [0008]    This arrangement is based on the use of chemicals reacting with the odor vapors emanating from the lagoon, rather than on creating a physical barrier which prevents the vapors from spreading in the environment. 
         [0009]    This involves costs for the chemicals and for the associated plants. A further problem connected with this system is also the possible diffusion of the chemicals into the environment. 
       SUMMARY 
       [0010]    An embodiment of the present invention is a barrier device for withholding the odors released by a malodorous substance, particularly for purifying plants, which allows to simply and cost-effectively solve the aforesaid problems. 
         [0011]    According to an embodiment of the present invention, there is provided a barrier device for withholding odors released by a malodorous substance, particularly for purifying plants; the barrier device including a side structure surrounding said malodorous substance and delimiting laterally a volume above a free upper surface of said malodorous substance, and atomizing means for generating a layer of atomized liquid extending in said volume above said free upper surface of said malodorous substance so as to completely cover said free upper surface of said malodorous substance and isolate said malodorous substance from an external environment. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    One or more embodiments of the invention will now be described with reference to the accompanying drawings which show a non-limitative embodiment. 
           [0013]      FIG. 1  is a plan view showing a barrier device for withholding odors released by a malodorous substance, particularly for purifying plants according to the present invention. 
           [0014]      FIG. 2  shows a section taken along the line II-II in  FIG. 1 . 
           [0015]      FIG. 3  is similar to  FIG. 1  and shows, with parts removed for clarity, a variant of the barrier device of  FIG. 1 . 
           [0016]      FIG. 4  shows a section taken along the line IV-IV in  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION 
       [0017]    In  FIGS. 1 and 2 , numeral  1  designates as a whole a tank (partially shown), in particular a tank of a purifying plant (not shown), which contains a malodorous substance  2 , for example sludge or sewage treated in such purifying plant, having an upper free surface  3  ( FIG. 2 ) from which gasses and consequent unpleasant odors are released upwardly. 
         [0018]    The tank  1  includes a vertical side wall  4  having, in plan, a circular profile and provided with an upper end portion or edge  5  ( FIG. 2 ) which protrudes upwardly with respect to the surface  3  and is defined by an outer cylindrical surface  6 , an upper flat surface  7  and an inner cylindrical surface  8 . 
         [0019]    The wall  4  carries a barrier device  10  which withholds the unpleasant odors released by the surface  3  and includes a cylindrical side structure  11  upwardly extending from and prolonging the wall  4 , for example by approximately 2.5 meters. 
         [0020]    The structure  11  defines an upper opening  12  and includes a plurality of vertical posts  14 , which are defined by respective sectional members with a T cross-section, reciprocally equally spaced apart along the edge  5 , and each comprising a respective web  15  and a respective fin  16 , reciprocally orthogonal. In particular, the web  15  of each post  14  ends downwards with a segment  17  ( FIG. 2 ) coupled in contact with the surface  6  and integrally connected to the edge  5 , so that the surface  7  is left free for the circular advancement path of a possible screen rake carriage (not shown), while the fins  16  are radially facing outwardly. 
         [0021]    The structure  11  further includes a plurality of vertical panels  19 , which are interposed between the fins  16  of the posts  14 , rigidly connected to the pitches  15  and essentially coupled airtightly on the edge  5 , in a way not described in detail, at their own lower ends. 
         [0022]    The device  10  further includes an atomizer  21 , which generates, in use, a layer  22  of atomized liquid, preferably water, in the volume extending above the surface  3  and laterally delimited by the side structure  11 , so as to completely cover the surface  3  and isolate the malodorous substance from the external environment. 
         [0023]    The atomizer  21  includes a circular manifold  24  which receives pressurized water from a control and feed power unit  25  (schematically shown) through a line  26 . 
         [0024]    The manifold  24  is housed in the structure  11 , coupled with posts  14  in fixed position and spaced apart from the surface  7  by respective securing or fastening devices  28  (schematically shown) and presents a plurality of outlets defined by respective atomizing nozzles  29 . 
         [0025]    The nozzles  29  are arranged around the periphery of the surface  3 , preferably at intermediate positions between the devices  28 . The nozzles  29  are directed radially inwards form the manifold  24 , in a horizontal direction, are equally reciprocally spaced apart along the manifold  24  and are shaped to generate, under the pressure generated by the power unit  25 , the layer  22  which has an adjustable height H, for example between 1 and 2 meters, and is in a vertically spaced apart position from the surface  3 , for example by approximately one meter. 
         [0026]    The pressure generated by the power unit conveniently ranges between 50 and 150 bar. 
         [0027]      FIGS. 3 and 4  show a variant of the tank  1  and the barrier device  10 , in which the components are indicated, where possible, with the same reference numerals used in  FIGS. 1 and 2 , followed by the reference letter “a”. 
         [0028]    Tank  1   a  differs from tank  1  in that it is rectangular, in plan, whereby also structure  11   a  and manifold  24   a  present a substantially rectangular annular shape. Unlike panels  19 , panels  19   a  present respective vertical lower end portions  32  having a height, for example, of approximately 2 meters, and respective upper end portions  33  slanted by approximately 45° with respect to the respective portions  32  reciprocally converging upwardly and towards the centre of opening  12   a , and having, for example, a height of approximately 0.5 meters. 
         [0029]    Furthermore, unlike the device  10 , posts  14   a  end downwards with respective base brackets  34  resting on and integrally connected to a surface  7   a.    
         [0030]    In use, atomizer  21 ,  21   a  generates the layer  22 ,  22   a , which essentially consists of a “mist” or “cloud” of water droplets which entirely covers surface  3 ,  3   a , defining an upper barrier for unpleasant odors, while structure  11 ,  11   a  provides a containment and lateral shielding function for the layer  22 ,  22   a  to keep it in stabile conditions also in the presence of wind. The gasses released by the surface  3 ,  3   a  are intercepted by the layer  22 ,  22   a  before reaching the external environment and, being soluble in water, are absorbed by the droplets of the layer  22 ,  22   a  with a high efficiency thanks to the large exchange surface defined by the droplets themselves. 
         [0031]    The efficiency of the cover and the unpleasant odor withholding is then increased by the possible presence of the portions  33  slanted or curved towards the centre of the opening  12   a.    
         [0032]    The droplets of the layer  22 ,  22   a  progressively fall by gravity onto the surface  3 ,  3   a , thus contributing to controlling the temperature, and thereby, the stability of the treatment process of the substance  2 ,  2   a . This is because the droplets of the layer  22 ,  22   a  are relatively cold and, falling back on the substance  2 ,  2   a , help to keep the temperature in the tank  1 ,  1   a  low, for example at approximately 20° C., that is at an optimal temperature for bacterial treatment. 
         [0033]    The falling of droplets of the layer  22 ,  22   a  onto the substance  2 , 2   a  can also contribute to abating the presence of possible foams on the surface  3 ,  3   a.    
         [0034]    Advantages of the device  10 ,  10   a  are apparent from the operative mode described above. 
         [0035]    Moreover, the device  10 ,  10   a  allows one to simply and rapidly perform visual inspections inside the tank  1 ,  1   a  and/or collect samples of the substance  2 ,  2   a  and/or maintenance operations without dismantling any component of the device  10 ,  10   a  because the vision and the access inside the tank  1 ,  1   a  are not fully obstructed by the layer  22 ,  22   a . When needed to eliminate the layer  22 ,  22   a  to perform interventions in the tank  1 ,  1   a , it will simply suffice to deactivate the feed of power unit  25 . 
         [0036]    The device  10 ,  10   a  allows the use of plain water which can be taken also from a well or river, or be recycled water. 
         [0037]    Furthermore, the manifold  24 ,  24   a  makes the jet of the various nozzles  29 ,  29   a  and thereby the layer  22 ,  22   a  essentially uniform. Also, the atomizer  21 ,  21   a  is relatively simple. 
         [0038]    Finally, from the foregoing, it is clear that changes and variations can be implemented to the device  10 ,  10   a  described without departing from the spirit and scope of this disclosure. 
         [0039]    In particular, the manifold  24 ,  24   a  may not be annular and/or may be fitted directly on the edge  5 ,  5   a  of the wall  4 ,  4   a  without additional structures  11 ,  11   a  if the surface  3 ,  3   a  is relatively low with respect to the edge  5 ,  5   a  itself or may be adjustable in height along the posts  14 ,  14   a.    
         [0040]    Furthermore, the device  10 ,  10   a  may be used for malodorous substances contained not only in tanks but also in “open-air” conveying channels or also in closed tanks. In this respect, it is to be noted that the power needed to feed the atomizer  21 ,  21   a  with water is substantially less, e.g. one fifth, than the power required to suck out odor vapors from the tank and have them pass through a filter, i.e., an active carbon filter.