Patent Publication Number: US-8974604-B2

Title: Sewer cleaning method

Description:
This invention relates to a method for cleaning sewer drains using a jet nozzle system which carries collected solids to a discharge points for extraction. 
     BACKGROUND OF THE INVENTION 
     Examples of systems of this type are shown in U.S. Pat. Nos. 4,699,163 and 5,720,309 (issued Feb. 24, 1998) both of the present inventor which includes an elongate pipe section having a rear end for connection to the hose and a forward end connected to a cylindrical housing. At a rear face of the housing is provided a plurality of rearwardly extending jets surrounding the pipe section. A plurality of skid bars are attached to the housing longitudinally of the housing at angularly spaced positions around the housing with those skid bars extending from the rear face of the housing rearwardly and inwardly for attachment to the pipe section. 
     Further examples are shown in U.S. Pat. No. 3,380,461 (Maasberg), U.S. Pat. No. 3,678,948 (Hedges assigned to Rockwell Manufacturing Co.); U.S. Pat. No. 3,814,330 (Masters assigned to McNeil Corporation) and U.S. Pat. No. 4,073,302 (Jones). 
     Masters shows a nozzle having four lobes each lying in a substantially axial plane with the lobes arranged at right angles and each lobe carries two jet nozzles. This arrangement is disadvantageous in that the nozzles are carried on the lobes and therefore can be engaged into the material at the base of the pipe thus reducing flow. 
     Maasberg discloses a head which is generally a flat body with nozzles at the front face. Again the nozzles can engage into the material reducing flow. 
     Hedges discloses a relatively complex arrangement with two heads carried on a central fin section with the fins welded to a connecting pipe section at spaced positions around the axis of the pipe section. This arrangement is relatively complex and bulky so that the cost of manufacture is increased and the proper flow of material and flushing water may not be achieved. 
     Jones discloses an arrangement with skids which run on the inside surface of the pipe with a simple nozzle and is therefore carried centrally of the pipe. This arrangement is impractical in view of the difficulty of running along the length of the pipe which can have obstructions, bends and the like. 
     SUMMARY OF THE INVENTION 
     It is one object of the invention to provide an improved sewer cleaning method. 
     According to one aspect of the invention there is provided a method for cleaning a sewer pipe of collected solid materials comprising: 
     providing access to the pipe at first and second longitudinally spaced locations; 
     providing at the first location a hose system including a hose supply and pulling device for releasing and withdrawing the hose system and a cleaning liquid supply system for supplying cleaning liquid to the hose system; 
     providing at the second location a pulling system including a cable and a device for releasing and pulling in the cable; 
     providing at the second location an extraction system for extracting solid materials drawn to the second location; 
     in a first step at the first location, attaching the hose system to a first jet nozzle head and causing the first jet nozzle head with the hose system attached to move from the first location to the second location by directing the liquid from the first jet nozzle head toward the first location so that the flow of liquid acts to drive the first jet nozzle head along the pipe toward the second location while pulling the hose system along the pipe; 
     in a second step, withdrawing the hose system to the first location with the cable attached so as to pull the cable to the first location; and 
     in a third step, with the cable and the hose system attached to a second jet nozzle head, pulling the cable back toward the second location to cause the second jet nozzle head to move from the first location to the second location with the hose system pulled behind the second jet nozzle head from the first location while directing the cleaning liquid from the second jet nozzle head toward the second location so that the flow of cleaning liquid acts to drive the solid materials along the pipe to the second location for extraction at the second location. 
     As will be appreciated by a person skilled in this art, the term “cable” used herein can include other pulling elements such as cord, string, chain to be wound onto a winch. However it is intended that the cable does not act as a liquid supply so that it is not a hose. 
     In this way the cable or pulling element has only a small diameter less than that of supply hose so that it does not interfere with the cleaning of the pipe. The hose system supplying the cleaning liquid to the second head is pulled behind the head in the cleaned pipe so that it does not interfere with the movement of the movement of the second head in the pipe or the movement of the solids and liquid in the pipe in front of the second head. 
     In the third step the hose supply system can include a plurality of hoses for supplying a high quantity of liquid. As these hoses are pulled behind the second head the number and bulk of the additional hoses does not interfere with the cleaning action. In this way the level of liquid can be maintained very high to provide the best cleaning action. 
     As the second cleaning head is designed without necessity for considering the function of carrying the head through the pipe in the first step, it allows the design to be arranged which maximizes the cleaning effect. 
     In the first step the first head generally will be attached to a single hose for supplying a sufficient quantity of liquid only to transport the jet nozzle system to the second location. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       One embodiment of the invention will now be described in conjunction with the accompanying drawings in which: 
         FIGS. 1 ,  2  and  3  show schematically three steps in the process according to the present invention. 
     
    
    
     In the drawings like characters of reference indicate corresponding parts in the different figures. 
     DETAILED DESCRIPTION 
     A method for cleaning a sewer pipe of collected solid materials using an apparatus designed for the method is shown in  FIGS. 1 to 3 . 
     The method is used with a pipe  10  to be cleaned of collected debris including sand, gravel, sticks and other material which can enter such pipes add tends to settle along the length of the pipe. Such pipes for use with the method described herein are typically of a large diameter, greater than 24 inches since such pipes are much more difficult to clean so that the method described provides an enhanced cleaning action. However there is no limit on the size of pipe to be cleaned. 
     Access to the pipe is provided at a first location  11  and at a second longitudinally spaced location  12 . These are typically pre-constructed openings with vertical access to the ground and are spaced along the pipe at convenient intervals to grant suitable access for cleaning, repair and inspection. 
     At the first location  11  is provided a hose system  13  including a hose supply  14  mounted on a reel  15  acting as a pulling device for releasing and withdrawing the hose  16 . The reel and hose supply are mounted in a jet truck  17  with a cleaning liquid supply system including a pump  18  and a tank  19  for supplying cleaning liquid, generally water, to the hose system. Jet trucks of this type are well known and widely used in the pipe cleaning business so that no further detail is required here. As shown in the figures there is a single truck illustrated supplying a single hose  16 . However more than one truck can be provided in most cases to supply a larger quantity of liquid through additional hoses. 
     At the second location  12  is provided a pulling system including a cable  20  and a winch  21  for releasing and pulling in the cable  20 . Also at the second location is provided an extraction system  22  including a vacuum truck  23  and a vacuum hose  24  attached thereto for extracting solid materials out of the vertical access pipe  12 A at the second location. Vacuum trucks of this type are well known and widely used in the pipe cleaning business so that no further detail is required here. 
     The system further includes a first jet nozzle head  25  for use in a first step of the method and a second jet nozzle head  26  for use in a second step of the method. Each of these heads is of the type generally shown in one or more of the above patents, the disclosures of which are incorporated herein by reference. Thus each head includes a body  27  which can slide along the pipe with a connection  28  to a hose  16  and one or more nozzles  30 . A typical example is shown in the figures of U.S. Pat. No. 4,499,163 referenced above. The body may include skids which enhance its movement along the pipe. 
     At each of the first and second locations is provided a guide roller  11 B,  12 B for guiding the movement of the cable  20  and the hoses from the vertical section  11 A,  12 A into the pipe 
     In a first step shown in  FIG. 1 , at the first location  11 , the hose  16  from the truck  17  is attached to the first jet nozzle head  25  with the hose system attached to the rear of the head with the jet nozzles  29  arranged to direct the liquid rearwardly toward the first location  11 . This causes the head to move from the first location  11  along the pipe to the second location  12  by directing the liquid from the first jet nozzle head toward the first location  11  so that the flow of liquid acts to drive the first jet nozzle head along the pipe toward the second location  12  while pulling the hose  16  along the pipe. The head can be of a simple construction since its only function is to drive along the pipe with no cleaning action being required. 
     In a second step shown in  FIG. 2 , at the second location  12 , the cable  20  is attached to the head  25  and the hose system  15  is withdrawn by winding the hose  16  onto the reel  15  so that the head  25  is pulled back to the first location  11  with the cable  20  attached so as to pull the cable  20  to the first location  11 . The head  25  can alternatively be removed at the second location  12  and the cable  20  attached directly to the hose  16  at a forward end coupling. In a yet further alternative, the head  25  can be removed at the second location  12  and replaced by the second head  26  (shown in  FIG. 3 ). It will be appreciated that the function of the second step is to carry the cable  20  to the first location  11  and hence the presence or absence of the heads  25  or  26  is of little importance. 
     In a third step shown in  FIG. 3 , the cable  20  and the hose system are attached to the second head  26  which is then pulled by the cable  20  back toward the second location  12 . In this step, the second head  26  is arranged with the nozzles  28 A facing toward the second location  12 . The head is attached to the hose  16  which extends from the head to the location  11  and thus drags behind the head in the cleaned pipe as the head is pulled forwardly to the second location  12 . One or more additional hoses  16 A fed from additional jet trucks can be provided from the location  11  into the pipe to supply additional cleaning liquid to ensure sufficient flow to provide an effective cleaning action. 
     The head  26  is thus pulled from the first location  11  to the second location  12  with the hose system pulled behind the head extending to the first location. The nozzles  28 A act to direct the cleaning liquid from the head toward the second location  12  so that the flow of cleaning liquid acts to drive the solid materials along the pipe to the second location  12  for extraction at the second location  12  by the vacuum system  22 . 
     As the pipe in front of the head as it moves is unencumbered by thick hoses, the cleaning action can be more effective. 
     Since various modifications can be made in my invention as herein above described, and many apparently widely different embodiments of same made within the spirit and scope of the claims without department from such spirit and scope, it is intended that all matter contained in the accompanying specification shall be interpreted as illustrative only and not in a limiting sense.