Abstract:
A condenser tube cleaning nozzle which is cushioned with resilient washers. The present invention provides a stiffened nozzle adapted to handling high pressure, while at the same time providing cushioning at all contact points on a tube sheet and within a particular tube being cleaned.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    This invention relates to an apparatus for cleaning a tubular member, and in particular, to a cleaning nozzle for a condenser tube.  
           [0002]    This invention will generally be described in connection with tube cleaners for heat exchanger and condenser tubes. However, it is to be appreciated that the invention has application to a wide variety of tubes and that the scope of the invention is not limited to such cleaners.  
           [0003]    Heat exchangers and condensers often contain a large number of metal tubes through which heat exchanging fluid flows. The tubes are usually arrayed in parallelism and are supported adjacent their ends by transverse tube sheets. Over time, the tube sheets become heavily pitted, corroded or worn away, thus weakening the entire structure. To prevent this, various coatings are applied to the tube sheets, thereby preventing or substantially retarding pitting, corrosion and wear on the tube sheets.  
           [0004]    It is well known that the operating efficiency of heat exchangers and condensers is reduced and fluid flow is restricted when the condenser tubes become fouled by such deposits as scale, algae, mud, slime and the like. In addition, if the tubes are not cleaned regularly, deposits may cause pitting or corrosion of the tubes, resulting in major damage and shortened tube life.  
           [0005]    The interior of tube members such as a heat exchanger tube are generally cleaned by forcing a pressurized cleaning medium, e.g., pressurized gas/particulate solid mixture, water, water/solid slurry, etc., through the tubular member. In the prior art, tube cleaning generally involved the insertion of brass nozzles into a tube and subjecting the tube interior to high pressure from compressed air or water. However, it has been determined that the use of metallic nozzles damages the tube sheet coatings about the tube end. As a result, the prior art now generally uses nylon nozzles. However, this still puts pressure on the coating about the tube ends and damaging the coating. Because nylon nozzles are soft, they do not work well under high pressure uses.  
           [0006]    All existing tube cleaning nozzles are conical in shape and made from metal of plastic. The existing nozzles contact the tube sheet coating when placed in the tube. This contact frequently results in damage to the tube sheet coating.  
         SUMMARY OF THE INVENTION  
         [0007]    The present invention addresses the limitations of prior art devices by providing a nozzle which is cushioned with soft washers. The present invention provides a stiffened nozzle adapted to handling high pressure, while at the same time providing cushioning at all contact points on the tube sheet and within the tube being cleaned.  
           [0008]    These together with other objects of the invention, along with various features of novelty which characterize the invention, are pointed out with particularity in the claims annexed hereto and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated a preferred embodiment of the invention. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    [0009]FIG. 1 is a perspective representation of a typical tube bundle of a heat exchanger with a cleaning system attached.  
         [0010]    [0010]FIG. 2A is a side elevational view of a nozzle constructed according to the principles of the present invention.  
         [0011]    [0011]FIG. 2B is a rear view of the nozzle of FIG. 2A.  
         [0012]    [0012]FIG. 3 is a side view, partly exploded, of the nozzle of FIG. 2A.  
         [0013]    [0013]FIG. 4 is a sectional view of the invention nozzle along the section lines A-A of FIG. 2B.  
         [0014]    [0014]FIG. 5 is a view of the invention nozzle inserted into a tube within a tube bundle. 
     
    
     DETAILED DESCRIPTION OF INVENTION  
       [0015]    Referring to the drawings in detail wherein like elements are indicated by like numerals, there is shown in FIG. 1 a typical heat exchanger bundle  10  comprising a plurality of parallel tubes  12 , each tube  12  having an interior wall  13 . The heat exchanger bundle  10  includes a coated transverse tube sheet  14  having a series of apertures  16  that provide entrances into and support of the tubes  12 . A nozzle  2  is shown partially inserted into one of the tubes  12 . The nozzle  2  is connected to a conveying conduit  3  that in turn is connected to a hose  4  by a suitable coupling  5 , the hose  4  being connected to the output of a pump  6  that draws and pressurizes a liquid or gaseous medium from a tank  7  via line  8 .  
         [0016]    Referring to the drawings and particularly FIGS. 2A, 2B,  3 - 4 , there is shown a nozzle  20  constructed according to the principles of the present invention. The invention nozzle  20  has a generally hollow, cylindrical shape with a distal end  21  and a proximal end  22 , said ends  21 ,  22  defining the central, longitudinal axis of the nozzle  20 . The nozzle  20  may be segmented longitudinally into three sections, a rearward section  23  beginning at the proximal end  22  and extending forwardly a specific distance toward the distal end  21 , a middle section  24  extending forwardly a specific distance from the rearward section  23  toward the distal end  21 , and a forward section  25  extending forwardly a specific distance from the middle section  24  and ending at the distal end  21 . The diameter of the rearward section  23  is larger than the diameters of the middle section  24  and forward section  25 . The diameter of the middle section  24  is larger than the diameter of the forward section  25 . The foremost portion  26  of the forward section  25  is threaded about its outer surface  27 . The rearward, middle and forward sections  23 ,  24 ,  25  may be made from metal or plastic.  
         [0017]    A soft washer  30 , having a forward end  33 , a rearward end  39  and an inner diameter  31  slightly greater than the outer diameter of the middle section  24 , is fitted over the middle section  24  with the soft washer rearward end  39  against the forward end wall  28  of the rearward section  23 . The soft washer outer diameter  32  is approximately equal to the outer diameter of the rearward section  23 . A plurality of identical rubber washers  34 , typically made from neoprene, each having an inner diameter  35  slightly greater than the outer diameter of the forward section  25  are fitted over the forward section  25  and packed against the forward end wall  29  of the middle section  24 . The outer diameter  36  of each rubber washer  34  is slightly greater than the outer diameter of the middle section  24 . A threaded end cap  37  with an outer diameter  38  approximately equal to the outer diameter of the middle section  24  is threadingly engaged to the forward section foremost portion  26 .  
         [0018]    Referring again to the drawings and particularly FIG. 5, the nozzle distal end  21  is inserted into a tube  12  to be cleaned. The nozzle forward section  25  and a substantial portion of the middle section  24  is positioned within the tube  12 . The soft washer outer diameter  32  is too great to fit into the tube  12  and the washer&#39;s forward end  33  abuts and rests against the coating  15  on the tube sheet  14 . Because the nozzle end cap outer diameter  38  and outer diameter of the middle section  24  are less than the rubber washer outer diameters  36 , only the rubber washers  34  have contact with the tube interior wall  13 . When high pressure water and/or air is released through the nozzle into the tube  12 , the friction of the rubber washers  34  against the tube interior wall  13  provides resistance to the nozzle  20  being pushed back out of the tube  12  by the water and/or air pressure. By making the rubber washer outer diameters  32  slightly less than the inner diameter of the tube interior wall  13 , a “cocking” and “levering” effect is created with the nozzle. This creates additional friction at pressure points  40  between the tube interior wall  13  and the nozzle  20 , and also seals the tube  12  from back pressure. The soft washer  30  positions the nozzle  20 , prevents metal from contacting the tube sheet coating  15  at normal contact points  41 , and absorbs and deflects any escaping back pressure to the cleaning nozzle operator.  
         [0019]    It is understood that the above-described embodiment is merely illustrative of the application. The invention nozzle  20  is adapted to be attached to commonly used tube cleaning guns available in the prior art. Other embodiments of the invention may be readily devised by those skilled in the art which will embody the principles of the invention and fall within the spirit and scope thereof.