Patent Application
20100295198
The present invention relates to an apparatus and a method for lining an interior surface of pipe.
A method presently used for repairing pipelines includes the use of a liner tube having a felt layer on its inside and having a protective layer made of a polymer or other plastic material on its outside. The lining tube is vacuum-impregnated with a resinous material capable of curing and hardening in what is commonly referred to as a “wet-out” process. The wet-out process normally takes place in a wet-out facility, which may be at or remote from the job site. Just prior to wetting-out the liner, a catalyst is mixed with a resin so as to activate the resin and cause it to begin curing and hardening. The resin impregnated liner tube is then moved from the wet-out facility to an operative position wherein the liner tube can be inverted into the pipeline. Once the resin cures and hardens, the liner tube provides a new lining for the pipeline. Some resins are set to cure at ambient temperatures. In some instances, steam or hot water is applied inside the lining tube to speed the cure time.
One problem with the present method is that the catalyst must be mixed with the resin before the liner tube is wet-out and before positioning the liner tube at the damaged section of pipe. Once the catalyst is applied to the resin, the resin begins curing and time is of the essence in order to have the liner tube in place within the pipeline to be repaired. If the resin hardens before the liner tube is properly positioned within the pipe, it may require that a portion of the existing pipeline be dug up and replaced. If, on the other hand, a resin mix with a longer cure time is used to ensure adequate working time to install the liner, productivity suffers as the crew waits for the liner to cure and harden. Aside from the loss in productivity, additional costs are involved in maintaining a separate wet-out facility. There are also additional costs associated with retarding or accelerating the cure time. For example, following the wet-out process the lining tube can be packed in ice and stored in a refrigerator compartment of a truck or trailer to retard or prevent the resin from curing. To accelerate the cure time, a large boiler or other heat source is required at the job site. Such equipment and the additional labor increases the cost of the liner installation.
Therefore, a primary object, feature and/or advantage of the present invention is the provision of an improved method for repairing a damaged section of a pipeline.
A further object, feature and/or advantage of the present invention is a new apparatus and method for lining a pipe that does not require a wet-out facility.
A further object, feature and/or advantage of the present invention is a new apparatus and method for lining a pipe that allows a lining tube to be vacuum impregnated while in the pipeline.
A still further object, feature and/or advantage of the present invention is the provision of a new pipelining system that does not require a bladder.
A further object, feature and/or advantage of the present invention is the provision of a new apparatus and method for lining a pipe that is unaffected by ground water and other materials in the host pipe.
A still further object, feature and/or advantage of the present invention is a new lining method that allows for extremely fast cure times to greatly improve productivity.
Yet a further object, feature and/or advantage of the present invention is the provision of a new apparatus and method of pipeline repair wherein a resinous material is applied to the liner in a controlled environment while in the pipe in need of repair.
A further object, feature and/or advantage of the present invention is the provision of a new method and means for repairing a damaged section of pipe that is more cost-effective than prior art methods.
These and/or other objects, features and/or advantages of the invention will become apparent with reference to the remainder of the specification and claims.
One aspect of the invention includes a method of rehabilitating a damaged section of pipe that generally includes taking an elongated tubular liner, taking a dispensing unit adapted to receive a portion of the liner, inverting the liner in the pipe with an inverting end of the liner received by the dispensing unit, applying a pumpable material capable of curing and hardening from the dispensing unit to the inverting end of the liner as the liner inverts within the pipe, and pressing the liner against the damaged section of pipe until the resinous material cures and hardens.
In a preferred form, the pumpable material is a resinous material, and a dry liner substantially free of any resinous material is inverted into the pipe and the resinous material is applied under pressure to the inverting end of the liner tube. The liner is preferably maintained in a compressed state until it reaches the inverting end wherein the liner tube decompresses and absorbs the resinous material applied under pressure by the dispensing unit. The lining tube preferably includes a fabric layer that is resin impregnable and a plastic coating that is impermeable thereby allowing the bladder to be pressurized during the inversion process.
Another aspect of the invention includes an assembly for lining an interior of a pipe. The assembly generally includes a feeding pump, a static mixer in communication with the feeding pump for mixing a resin catalyst to form a resin mix, and a dispensing unit adapted to receive an inverting end of an elongated tubular liner and dispense the resin mix under pressure to the inverting end of the liner. Preferably, the dispensing unit is operatively connected to a first reel and first motor and the liner is operatively connected to a second reel and second motor wherein the reels are electronically controlled and in communication with one another to control the way in which the liner and dispensing unit move along the interior of the pipe. The nozzle may include a flexible end portion adapted to move around irregular surfaces on the interior of the pipe.
The present invention allows a dry liner to be wet-out or eventually vacuum impregnated within the pipeline in a controlled environment. This allows the use of a resinous material with an aggressive cure time, which greatly improves productivity. In addition, a separate wet-out facility is no longer required. The present invention also obviates the need for heating and cooling sources to be provided at the job site to either retard or accelerate the cure time of the resinous material.
The present invention contemplates repair of all kinds of pipelines, including, but not limited to, mainline sewer pipelines, lateral sewer pipelines, gas pipelines and potable water pipelines.
Referring to
Adjacent the downstream manhole 62 is a truck 58 having resin pump A 70 and a reservoir A 72 and catalyst pump B 76 and a reservoir B 78 mounted thereon. Hose 68 and hose 74 extend from the reservoirs A 72 and B 78, respectively, down to a static mixer 28 housed within a small tractor 10 shown within the pipeline 64. The hoses 68 and 74 may also include electronic cables for controlling the tractor 10.
A two-part resin including a resin with a catalyst is an example of a pumpable material capable of curing that is suitable for use with the present invention. The suitable resin mixture is an epoxy resin set at a 1:1 resin to catalyst mix ratio, Rhino Linings product no. 1310T. Rhino Linings is located at 9090 Kenamar Drive, San Diego, Calif. USA 92121. A single component resin, such as a UV cured resin, could also be used, which would obviate the need for a static mixer 26 as shown. Many variations of resinous liquid polymers are available for use with the invention and the resin and catalyst mixture may range from 1:1 to 100:2. The later range would be more typical when using a polyester resin rather than an epoxy resin. Other pumpable materials may be used with the invention such as mortors or other pumpable materials capable of being impregnated into the liner tube and curing to form a rigid new pipe lining.
The preferred two-part resin is pumped from pump A 70 and pump B 76 to inputs 16 and 18 of the static mixer 28. The resin is fed via hose 68 to input 16 and the catalyst is fed via hose 74 to input 18 and completely mixed within the static mixer 28. The resulting mixture is distributed from output 22 of the static mixer 28 and into the interior cavity of the nozzle of the dispensing unit 25.
Static mixers incorporate a series of geometric mixing elements that are made from metal or a variety of plastics fixed within a cylindrical (tube) or squared housing, which use the energy of the flow stream to create mixing between two or more fluids. Likewise, the mixer housing can be made from metal or plastic. Typical materials of construction for the static mixer components include clear PVC, gray PVC, stainless steel, ductile iron, polypropylene, Teflon, Kynar, fiberglass and polyacetal.
Hoses 68 and 74 are wound through a take-up reel 80 outside and above the downstream manhole 62. The hoses 68 and 70 are banded as designated by the reference numeral 110. In addition to acting as a conduit for the pumpable material, the banded hoses 110 also help to properly position and move the dispensing unit 25 along the pipeline 64. The take-up reel 80 controls the length the banded hoses 110.
Outside and above the upstream manhole 60 is a pressurized reel 30 which contains an outer cylindrical housing 32 and a center roller 34. A pressure inlet valve 36 in the housing 32 provides communication from the interior of the housing to a pressure hose 38. Pressure hose 38 is preferably connected to a pneumatic source of pressurized air. However, other fluids could be used without detracting from the invention.
The pressurized reel is shown in greater detail in
The liner tube 42 is comprised of a felt layer 31 and a plastic layer 33 (see
Referring again to
In operation, the liner tube 42 must be properly positioned initially relative to the dispensing unit 25. A length of the liner tube 42 is dropped into the upstream manhole 60 adjacent the opening to the main pipeline 64. An operator in the manhole 60 can then position the inverting face 56 of the liner tube 42 inside the nozzle of the dispensing unit 25. The inverting face 56 of the liner tube 42 should extend at least partially into the cavity of the nozzle adjacent the dispensing area for the resin mix. The valve 36 is then moved to its open position and fluid pressure, preferably air, as introduced into the interior of the reel 30 such that the liner tube 42 inflates and the pull rope 52 becomes taught. Similarly, the banded hose lines 110 running to the tractor 10 are also pulled taught by the take up reel 80. The resin and catalyst are then pumped from the truck 58 through lines 110 and through the output 22 of the static mixer 28 and through the nozzle of the dispensing unit 25.
Once the resin mix is dispensing into the nozzle of the dispensing unit 25, the reels 80 and 30 are put into a sync mode such that the dispensing unit 25 travels at substantially the same pace and is in synch with the inverting face 56 of the liner tube 52. The reels 80 and 30 are smart reels that communicate electronically with each other through a data cable 82, as is known in the art. Each reel is operatively connected to a motor. The motors are preferably DC motors, and one of the motors may be positioned within the pressurized reel vessel. It is preferable that the rotational speed of the take up reel 80 be slightly less than the rotational speed of the pressurized reel 30, as this avoids the inverting face 56 of the liner tube 42 separating from the dispensing unit 25. The force applied by the inverting liner tube 42 helps push the dispensing unit through the pipeline 64 as the reel 80 takes up the slack in the banded hose lines 110. The resinous material also acts as a natural lubricant on an inner surface 35 the dispensing unit 25, as the liner tube 42 moves against the inner surface.
As disclosed previously, a rope 52 is attached to the liner tube 42. However, one could use a hose rather than the rope 52. The hose could be attached to a vacuum pump. As the dry liner tube 42 is loaded into the pressurized reel 30, a vacuum is drawn, and the vacuum kept on during inversion of the liner tube 42.
In a preferred form of the invention, a separate bladder tube is not used to inflate the liner tube 42; however, a bladder tube can also be inverted with the liner tube, if desired. This would eliminate the need for a plastic coating or layer 33 on the liner tube 42.
Those skilled in the art, having the benefit of this disclosure, will appreciate the numerous advantages achieved by the present invention. Of course, no separate bladder is required. In addition, the present invention avoids the problems associated with wetting out a liner and either retarding or accelerating the cure rate to accommodate the “working” time. Workers are often constrained by working time. There is limited amount of time to get the liner in place after the resin is mixed. The liner must be wetted out and installed before it cures. Once the liner is properly positioned within the pipe, then it is preferable to speed up the curing process, which may be done by introducing steam, heat, etc. Using the present invention, the wet out process essentially occurs within the pipe and a fast cure time is therefore appropriate. That is, the use of the present invention enables an aggressive cure schedule, which greatly improves productivity. And because the liner tube 42 stays compressed until reaching the inverting end where it decompresses and the resin mix applied under pressure in a controlled environment, the resin is applied well throughout the liner tube.
In the drawings and specification there has been set forth a preferred embodiment of the invention, and although specific terms are employed, these are used in a generic and descriptive sense only and not for purposes of limitation. Changes in the form and the proportion of parts as well as in the substitution of equivalents are contemplated as circumstances may suggest or render expedient without departing from the spirit or scope of the invention as further defined in the following claims.
