Abstract:
A method of creating a self-supporting waterproof lining in an underground pipe involves pulling a small carriage through the pipe and operating a rotary sprayer mounted on the carrier to spray an air-atomized, fast-setting organic compound on the interior of the pipe. Supply lines for air and the two parts of the compound pass through a union from the non-rotary carriage to the rotary sprayer.

Description:
This application claims priority from the corresponding provisional application having serial No. 60/238,804 filed on Oct. 6, 2000. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to a method for in-situ waterproofing of underground pipes by causing a wheeled vehicle carrying a rotary sprayer to pass through a length of pipe while spraying a fast setting organic waterproofing compound onto the interior of the pipe. 
     BACKGROUND OF THE INVENTION 
     Underground sewer and storm drainage pipes are typically made of concrete or masonry. As they get older, they become more and more permeable. Also, it becomes more and more likely over time that joints will have opened or separated due to ground movement. The result is pipes which leak water or other materials, absorb water from the outside and are susceptible to collapse and crumbling due to the deterioration of the concrete or masonry walls. Once these pipes are installed underground they are extremely difficult to repair even though access through manholes and the like may be provided at intervals such as 50′ to 300′. Often the repair of such underground pipes involves digging them up and replacing them. 
     SUMMARY OF THE INVENTION 
     The method of the present invention, generally described, involves placing a rotary spray device capable of generating a cylindrical; i.e., 360° spray pattern into a pipe to be lined on the interior surfaces thereof, using the device to spray a fast setting organic compound onto the interior of the pipe or line while causing the device to travel through at least the length of the pipe and, thereafter, removing the device from the pipe. 
     It has been found that through the proper selection of materials to be sprayed, typically using air for atomization, an extremely fast setup may be achieved which prevents sagging or dripping of the material from the interior surfaces of the line or pipe. Materials and air are typically supplied to the spray device from the surface through supply lines and the device, although it may be self propelled, it is typically pulled through the lines for a length of between, for example 50′ and 300′. 
     The apparatus aspect of the present invention provides a wheeled carrier which, as hereinafter described is preferably constructed in two longitudionally spaced parts, a rotary spray device of conventional design mounted on the carrier between the spaced parts for rotation about an axis which is parallel to the longitudinal axis of the pipe or line through which the vehicle is moved, thereby to provide a cylindrical spray pattern. The apparatus further comprises a motor, typically an air motor, mounted on the carrier for rotating the spray device about said parallel axis and one or more supply lines for conveying air and material to the spray device from a remote supply location. 
     As indicated above the wheeled carrier and the rotary spray device are caused to be moved through a length of pipe or line and the supply lines and motor are operated to cause a cylindrical spray pattern of material to be deployed from the device to the interior surfaces of the pipe through which the device moves. By using a fast setting two part compound of organic materials, use of the apparatus can create a self-supporting waterproof structure within the interior of the old and potentially crumbling concrete or masonry pipe or line. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views, and wherein: 
     FIG. 1 is a perspective view of a wheeled carrier and rotary spray device constructed in accordance with the present invention. 
     FIG. 2 is a sectional drawing of a rotary union which is used to convey spray materials through a rotary joint i.e., from the stationary carrier to the rotary spray device of the device of the apparatus of FIG.  1 . 
     FIG. 3 is a view of the rotary spray device showing the interconnection of the supply lines. 
     FIG. 4 is an exploded view of a spray gun assembly usable in the system or apparatus of FIG.  1 . 
     FIG. 5 is a detail of the spray gun as modified in accordance with the present invention. 
     FIGS. 6 and 6A is a diagram of a typical application of the device or apparatus of FIG. 1 to an underground line or pipe. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     This invention relates to a rotary applicator for lining the inside of new and existing pipes with polyurea coating. Typical applications will be for relining or waterproofing tunnel-like or pipe-like concrete or masonry structures. However, there is no technical reason why the method and apparatus of the present invention cannot be used in connection with pipe or the like of any construction which is subject to deterioration over time. The unit is designed to apply a coating according to manufacturer specifications at a mil thickness required to create a self-supporting membrane that will eliminate leaks within the pipe. This technique is a “trenchless technology” and improves on current methods of in-ground pipe repair commonly used today. The coating is an approved material for this application but requires a rotary applicator to properly apply it into the interior of the pipes where the diameters are too small for a man to enter. 
     The polyurea coating material is a plural component, elastomeric product derived from a mixture of fast gelling amine and isocyanate components hereinafter designated component “A” and component “B”, respectively. The combination of the A and B components is hereinafter referred to as a “two-part amine compound”. Properly applied, the coating resulting from the mixture of the A and B components will produce a flexible, tough, resilient monolithic membrane with good water and chemical resistance that can be walked on or handled within one minute of application. The material can be sprayed directly to damp or cold surfaces and, with a gel time of less than two seconds, can be applied up to any thickness in one application including vertical and overhead surfaces. The fast gel time of the mixed components requires the material to be applied with spray application equipment. The general specifications for the equipment describe pumping equipment that will deliver the separate components at a 1:1 volume ratio, heated to 160-170° F., with a dynamic pressure of at least 1,000 psi. 
     The apparatus as seen in FIG. 1 includes a wheeled carriage having a leading portion  10 , a trailing portion  12 , an air motor  14  carried by the trailing portion  12 , a rear rotary union  16 , a front rotary union  18  and a rotary spray gun assembly  20 . 
     The leading cart portion  10  includes a plate like body  21  with plastic wheels  22  and the trailing carrier portion  12  includes a plate like body  23  having plastic wheels  24 . The wheels enable the device to be moved, in a manner to be subsequently described, through the interior of a pipe to be coated. 
     Rotary motor  14  is a standard air drive gear motor such, for example, as an air motor available from Gast Corporation of Benton Harbor, Mich. as Model No. 4AM-RV-575-GR20. 
     Rotary union  16 , as best seen in FIG. 2, is intended to define separate paths for components A and B which are to be mixed at the spray gun assembly  20  to form the polyurea compound. Component A may comprise, for example, amine terminated polyether resins, amine chain extenders, or MDI prepolymers and component B may comprise, for example, a polyol isocyanate. 
     Rotary union  16  includes an outer cylindrical housing  26  defining a central bore  26   a  and a rotary member  28  journaled in the bore  26   a  of the outer member and driven by the output shaft  30  of air motor  14 . Outer member  26  is fixedly mounted on an apron structure  32  forming a forward extension of trailing cart  12 . The path for component A in rotary union  16  comprises a port  26   b  in the outer member, an annular chamber  28   a  in the rotary member, a port  28   b  in the rotary member, and a central bore  28   c  in the rotary member. The path for component B through the rotary union  16  comprises a port  26   b  in the outer member, an annular chamber  26   c  in the outer member, a port  28   d  in the rotary member, an annular passage  28   e  in the rotary member, and a port  28   f  in the rotary member. 
     Rotary union  16  may comprise, for example, a unit available from Deublin Corporation of Waukegan, Ill. as Deublin Deu-Plex Motor No. 1690, modified to allow the rotary member to be driven by the output shaft  30  of the air motor. 
     Rotary union  18  is intended to provide separate paths for pressurized trigger air, and atomizing air, to be delivered to the spray gun assembly  20 . Union  18  is generally similar to union  16  and may also comprise a Deublin Due-Plex Model 1690 union. Specifically, union  18  may comprise an outer cylindrical member  34  defining a central bore  34   a  and a central rotary member  36  journaled in bore  34   a . Outer cylindrical member  34  is fixedly mounted on a channel bracket  37  mounted on leading cart  10 . The path for the atomizing air through the union for delivery to the spray gun assembly is defined by a radial bore  34   b  in outer member  34 , an annular chamber  34   c  in the outer member, a radial port  36   a  in the inner rotary member, an annular passage  36   b  in the inner member, and a radial port  36   c  in the inner member. The path for the trigger air through the rotary union  18  for delivery to the spray gun assembly comprises a radial port  34   d  in the outer member, an annular chamber  36   d  in the inner member, a radial port  36   e  in the inner member, and a central bore  36   f  in the inner member. 
     Spray gun assembly  20  includes a manifold structure  38  and a spray gun  40 . 
     Manifold structure  38  comprises left and right blocks  42  and  44  and upper and lower plates  46  and  48  (see also FIG.  3 ). Blocks  42  and  44  are sandwiched between upper and lower plates  46  and  48  using suitable fasteners with a space  50  defined between the blocks to accommodate spray gun  40 . Block  46  is suitably bored to define an inlet passage  42   a  and an outlet port  42   b  and block  44  is similarly bored to define an inlet port  44   a  and an outlet port  44   b . A nipple  28   g  on the forward end of inner rotary member  28  of union  16  is suitably received in port  42   a  and a nipple  36   g  on the forward end of rotary member  36  of union  18  is suitably received in port  44   a.    
     Spray gun  40  may be of the type available, for example, from Gusmer Corporation of Lakewood, N.J. as Part No. 2100J-CSTM, shown in FIG.  4 . 
     Spray gun  40  is suitably and fixedly positioned in the space  50  defined between blocks  42  and  44  and upper and lower plates  46  and  48  and includes a barrel  52  extending through opening  50 , a nozzle  54  and a manifold plate  56  including inlet ports  56   a  and  56   b  for receipt of components A and B for mixture in the nozzle (see also FIG.  5 ). 
     A conduit  60  directs component A from a suitable source to port  26   b ; a conduit  62  directs component B from a suitable source to port  26   b ; a conduit  64  directs pressurized air from a suitable source to air motor  14  for operation of the motor in known manner and rotation of output shaft  30 ; a conduit  66  directs pressurized atomizing air from a suitable source to port  34   b ; a conduit  68  directs pressurized trigger air from a suitable source to port  34   d ; a conduit  70  connects port  28   f  to port  56   a ; a conduit  72  connects port  42   b  to port  56   b ; a conduit  74  connects port  36   c  to a port  52   a  in the barrel  52  of the gun; and a conduit  76  connects port  44   b  to a port  52   b  in the barrel of the gun. Conduits  60  and  62  may be supported, for example, by a bracket  12   a  carried by trailing cart  12  and conduits  66  and  68  may be supported, for example, by a bracket  10   a  supported by leading cart  10 . 
     In use, and as seen in FIGS. 6 and 6A, the applicator is positioned in an underground pipe  78  requiring repair. The pipe may be accessible at opposite ends in known manner via manholes  80  and  82 . The applicator may be self-propelled or, as shown, may be pulled through the pipe utilizing a winch  84  positioned above around and powering a cable  86  directed by pulleys  88  and  90  into pipe  78  for connection to an eye bolt  92  provided on leading cart  10 . It will be seen that actuation of winch  84  in a sense to wind up cable  86  will have the effect of gradually pulling the applicator through the pipe  78 . Conduits  66  and  68  are preferably wound around cable  86  so as to provide convenient access to the conduits and facilitate the delivery of pressurized air through the conduits to the applicator. 
     Conduits  60 ,  62 , and  64  may be directed to the applicator via a cable bundle  94 . Cable bundle  94  may, for example, be paid out from a drum  96  located in the cargo bed of an aboveground motor vehicle  98  and directed to pipe  78  via pulleys  100  and  102 . A source of materials A and B may be positioned in the cargo bed of the motor vehicle for selective delivery to conduits  60  and  62 . The components are preferably delivered to the conduits  60  and  62  in heated form and the cable bundle  94  is preferably heated to maintain the temperature of the components flowing to the applicator. 
     As the applicator is pulled progressively through the pipe  78  to be repaired, pressurized air is supplied to air motor  14  via conduit  64  to rotate the spray gun assembly, pressurized air is delivered via conduit  68  and through union  18  to the spray assembly to trigger the gun, pressurized air is thereafter supplied through conduit  66  and through union  18  to the gun to provide atomizing air for the gun, and components A and B are delivered in heated form through conduits  60  and  62  and via union  16  to ports  56   a  and  56   b  of the gun. The components instantaneously mix and produce a gel coating which is sprayed by a nozzle  54  onto the inner wall of the pipe so that a coating of a desired mil thickness is uniformly applied to the interior surface of the pipe as the applicator is pulled through the pipe. The mil thickness of the coating applied will of course depend on such parameters as the speed with which the applicator is pulled through the pipe and the rate at which components A and B are supplied to the gun as the applicator is pulled through the pipe. The coating may be applied in one pass through the pipe or, alternatively, multiple passes may be made through the pipe to provide the desired thickness. The thickness may, for example, vary from between ¼- to ⅜- and may be self-supporting whereby to provide an effective repair to even pipes that are severely damaged. A movement rate through the pipe of one foot per minute has been found to provide an effective coating in most applications. 
     As stated above, underground sewer and storm drainage pipes, especially those made of concrete or masonry, are susceptible to deterioration over time due to the passage of fluids through the lines and pipes as well as to damage due to ground movement. Because they are installed underground at varying depths, they are difficult to repair through any method other than to dig the lines up and replace them. The process of the present invention obviates such extreme measures by using a rotary spray device to coat the inside surface of an in-situ sewer or storm drainage pipe with a fast setting organic material of such thickness and strength that it actually can be thought of as.creating a new pipe within the old pipe; i.e., the old pipe simply acts as a mold for the in-situ creation of a new long-lasting leak proof pipe within the old pipe. Setup time may be on the order of 5 seconds or less so that the material does not sag or run down the walls of the pipe. 
     An electrical line may also be run to the cart to supply power to and take signals from a TV camera mounted on the front of the cart for original inspection and/or process monitoring purposes. The wheels of the carts are plastic and may be configured to provide a centering feature when traveling the curved interior walls of a medium diameter pipe. The speed of rotation of the gun is approximately 10 rpm and spray pressure is approximately 1,000 psi. The A and B components of the epoxy material are mixed within the nozzle of the gun and exit through a single needle valve controlled spray outlet. The components A and B are preferably heated to a temperature of 140 to 160° F. and maintained at that temperature as they are delivered to the cart via the heated cable bundle. Component A may comprise, for example, a polyurea resin in liquid form and component B may comprise an isocyanate also in liquid form which accelerates the dry time and facilitates curing of the material. The components A and B may, for example, and as seen in FIG. 6, be provided in containers positioned within the vehicle  98  and arranged to feed their respective components to the hoses  60  and  62  positioned within the cable bundle  94 . It will be understood that the cable bundle  94  is paid out along with the applicator so that the supply hoses may follow along as the applicator moves along the pipe  78 . 
     In a similar manner, and as also seen in FIG. 6, the trigger air and atomizing air lines  66  and  68  are paid out and paid in at the winch  84  as the cart moves up and down the pipe  78 . Although the applicator is shown as being pulled manually through the pipe  78 , it is within the contemplation of the invention that the applicator could be self-propelled through the pipe. 
     While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiments but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as is permitted under the law.