Patent Abstract:
Taught herein are a method and apparatus for removing sediments, fouling agents and the like from fluid, in particular liquid, ducts and/or tanks, characterized in that the method comprises applying an ultrasound vibration to a plurality of points of the structure, duct or tank to be treated, said ultrasound vibration being continuously applied outside the structure at a given frequency and power.

Full Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    This invention relates to a method for removing sediments, fouling agents, and the like, from ducts and tanks and to apparatus adapted for use in said method. 
         [0003]    2. Description of the Related Art 
         [0004]    Build-up of debris or fouling agents in ducts and/or tanks carrying or containing impure or otherwise sediment-generating liquids represents a common problem in many technological areas. 
         [0005]    One of the fields most affected by this problem is ship-building, and particularly medium-high class pleasure boating. Inboard engines are provided with a seawater cooling systems wherein seawater is pumped up and subsequently discharged; seawater contains various micro-organisms of both animal and plant origin, which exhibit a tendency to establish and proliferate in cooling system ducts. This kind of sediments causes remarkable problems and damage to engine assemblies and has a high economic impact. The problem of sediment buildup can be solved by the use of washings with sodium hypochlorite solutions or other oxidizing agents capable of attacking such microorganisms. Of course, these chemical substances are environmental pollutants and their use is encountering more and more limitations. 
       SUMMARY OF THE INVENTION 
       [0006]    Accordingly, one aim of the present invention is to provide a method for removing sediments, fouling agents and the like from liquid ducts and/or tanks without using aggressive systems that can damage both the structure to be restored and the surrounding environment. 
         [0007]    Another aim of the present invention is to provide an apparatus for carrying out a method for removing sediments, fouling agents and the like from liquid ducts and/or tanks without using aggressive systems that can damage both the structure to be restored and the surrounding environment, said apparatus being simply made and easily applied to various kinds of structures affected by similar problems due to sediments and fouling. 
         [0008]    Thus, one object of the present invention is a method for removing sediments, fouling agents and the like from fluid, in particular liquid, ducts and/or tanks, characterized in that said method comprises applying ultrasound vibrations to a plurality of points of the structure, such as a duct or tank to be treated, said ultrasound vibration being continuously applied outside the structure at a given frequency and power. 
         [0009]    Another object of the present invention is an apparatus for applying ultrasounds to a structure, such as a duct, tank or the like, comprising suitably-powered ultrasound generating means, transducer means for the ultrasounds generated from said ultrasound generating means, said transducer means being connected to said ultrasound generating means through connecting means and being coupled to said structure through suitable coupling elements. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    Other advantages and features of the present invention will be apparent from the following description of an embodiment thereof, which is provided by way of illustration, and not by way of limitation, with reference to the accompanying drawings, wherein: 
           [0011]      FIG. 1  is a schematic representation of an embodiment of the apparatus according to the present invention; and 
           [0012]      FIG. 2  is a detail of  FIG. 1  showing a cross-section of a transducer assembly coupled to a duct. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0013]      FIG. 1  illustrates an embodiment of an apparatus for carrying out the method according to the present invention; reference numeral  1  denotes an ultrasound generating unit which is connected, through a plurality of wires  101 , to a plurality of transducer assemblies  2  which are coupled to a duct  3  through coupling elements  103 . 
         [0014]      FIG. 2  shows a detail of one transducer assembly  2  coupled to the duct  3 . The transducer assembly  2  comprises a substantially bell-shaped box-like body  102  whose open end is provided with a radially-projecting flange  132  for securing the body  102  to a plate  162  through screws  142 . A transducer  202  is attached to the plate  162  through an adhesive resin layer  212 , said transducer  202  being connected, through wires  141 , to connectors  121  fitted in an insert  122  which engages the opening of a tube piece  112  at the bottom of the body  102  of the assembly  2 . A cap  131  is mounted to the tube piece  112 , and this cap houses connectors  111  for connecting wires  101  from the ultrasound generating unit  1  to the transducer assembly  2  (see  FIG. 1 ). The plate  162  is axially provided with a threaded pin  172  which is coupled to a threaded sleeve  103  welded to the outer wall of said duct  3  through a welding seam  113 ; an annular sealing element  152  is provided between the plate  162  and the flange  142  of the body  102 . 
         [0015]    The method and apparatus for removing sediments, fouling agents and the like according to the present invention are further explained in the following. Taking the duct  3  as an example of a cooling duct for an inboard propulsion engine of a boat, build-up of fouling mainly due to microbiological components in seawater (phytoplankton, zooplankton) is a known problem; according to the method of the invention, this build-up can be prevented by continuously applying ultrasounds at a frequency in the range of 10 to 40 kHz, preferably in the range of 17 to 26 kHz, to the duct  3 . The frequency of the applied vibration mainly depends on the wall thickness of the structure to be treated; generally, the larger the wall thickness, the higher the frequency of the applied vibrations. The power used is usually in the range of 300 Watts to 2 kilowatts, and preferably in the range of 600 Watts to 1,000 Watts. The application to this type of duct is only one among different examples of application for the method and apparatus according to the present invention, which can actually be used whenever a build-up of sediments and/or fouling agents exists in structures which contain and/or carry fluids. 
         [0016]    The continuous application of ultrasound inhibits the formation of build-ups on the wall of the ducts and prevents the formation of fouling that can cause malfunctions in the cooling system. In this case, the main problem to be solved is how ultrasounds can be applied to the structure to be treated. In fact, it is necessary that vibration impacting the structure itself, e.g., a duct, is as smooth as possible, while avoiding that transducer means hinder the flow within the structure and that the morphology of the structure is dramatically modified. Furthermore, because of the substantially circular cross-section of a duct, it is necessary that vibration is effectively and completely transferred to the highest degree without substantially changing the structure of transducers. To achieve these results, the unique transducer is fitted into a transducer assembly of suitable construction such as to be coupled with the structure to be treated in a very simple way, said structure having in turn been modified to a very small extent. In order to install the transducer assembly in a stable and perfectly functional way according to the invention, a threaded sleeve is welded to the external surface of the duct. 
         [0017]    The transducer itself is housed in a substantially sealed container body  102 , and it is attached to a face of a plate through a suitable adhesive such as an epoxy resin, a polystyrene resin or the like, said plate being coupled to the sleeve which is welded to the duct. In this way, vibration is transferred to the duct, and this type of connecting system is well suited for structures greatly varying in shape and size, so as to allow for a wide use of the method and apparatus according to the present invention. 
         [0018]    Advantageously, the transducer assembly  2  is connected to wires  101  through connecting means  111 ,  121  which enable its complete removal and replacement. Moreover, the insert  122  in the tube piece  112 , along with the cap  131 , further assure sealing within the transducer assembly  2  and prevent wear thereof due to the action of external agents.

Technology Classification (CPC): 1