PRESSURE INFUSION LINING SYSTEM

Abstract

A method and system for applying a liner to an underground utility structure is provided. First a layer of epoxy is applied to the interior surface of the host pipe using a machine such as a spincast machine. A dry liner is inverted into the pipe directly behind the coating application at a limited speed and pressure. A drag is set on the inversion equipment relative to the speed of the epoxy spinner unit to control inversion speed. Once the liner is completely inverted the internal pressure of the liner is raised and infused into the uncured epoxy.

Claims

1. A method for installing a liner in an underground utility structure, having a substantially deteriorated and cracked interior surface, comprising the steps of: spray applying a resin coating to the interior surface of the pipeline; applying compressed air at a low pressure of between 3-5 psi to slowly invert a dry liner into the interior of said pipeline at a controlled inversion rate of less than or equal to 0.5 feet per minute and low inversion pressure whereby said inverting liner does not cause additional damage to said deteriorated interior surface; and slowly increasing a pressure on the interior of said dry liner to about 8-10 psi, after said liner is fully inverted to imbed said dry liner into said resin coating to fully bed said liner into said resin coating and to press said resin coating into said deteriorated and cracked surface.

2. The method of claim 1, wherein the dry liner is a non-woven fibrous material.

3. The method of claim 1, wherein said resin is an epoxy.

4. The method of claim 1 wherein the increased pressure of said liner is done using a calibration hose.

5. The method of claim 1, wherein said resin coating is applied using a spincast machine.

6. The method of claim 1, further comprising: supporting a length of said dry liner material on drum; controlling a speed that said drum rotates to limit a speed at which said dry liner is installed into said utility structure, using a controller that allows said dry liner to invert into a utility structure at a predetermined and controlled speed.

7. The method of claim 6, further comprising: applying a coating of resin using a spin cast machine to an interior of said underground utility structure.

8. The method of claim 6, wherein the dry liner is a non-woven fibrous material.

9. The method of claim 6, wherein said resin is an epoxy.

10. The method of claim 6, wherein the inversion rate of the dry liner is limited to 0.5 feet per minute.

11. The method of claim 7, wherein said resin coating is applied using a spincast machine.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In the drawings which illustrate the best mode presently contemplated for carrying out the present invention:

[0023] FIG. 1 is a schematic diagram of a liner inversion system of the present invention; and

[0024] FIG. 2 is a diagram of a lining inverter in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0025] Now referring to the drawings, the inversion lining system of the present invention is schematically depicted and generally illustrated in FIGS. 1 and 2. In most general terms a spincast epoxy coating machine 12 is set up at one end of the host pipe 10. The spincaster 14 is pulled through the host pipe 10 via winch 16 and cable 18, or by a rock bore machine. At the other end of the host pipe 10, a computer controlled inversion machine 20 is set up. The interior surface of the host pipe 10 is coated with wet uncured spray applied epoxy 21 at a set speed as the spincaster 14 is retrieved. The inversion machine 20 loaded with dry liner 22 inside the inversion bag 24 is inverted into the host pipe 10 and into the wet epoxy 21. The payout speed of the inversion liner 22 is computer controlled at a constant speed and internal pressure. The dry inversion liner 22 is forced through the wet epoxy at a controlled speed such that the slow rate of inversion prevents air from being trapped behind the inversion liner 22 as it is bedded into the epoxy and prevents twisting or binding when the inversion liner 22 navigates bends and turns in the host pipe 10.

[0026] Now discussing the system in detail, the present invention provides a method for installing a liner in an underground utility structure or pipeline, such as an underground water pipeline, drainage line, manhole, storage tank (above or below ground), conduit, culvert or the like. Installing such a liner enables a damaged utility structure to be repaired and salvaged and placed in a condition for normal use. While a variety of structures can be repaired using the method and system of the present invention, the term pipeline will be used as an illustrative example for the remainder of the disclosure.

[0027] In accordance with the method of the present invention, the interior surface of the pipeline to be repaired and salvaged is first prepared by removing excess debris and dirt. The preparation is preferably performed with the appropriate surface preparation material based on the pipe material and condition. The details of the preparation process will not be discussed further herein since such processes are well known in the art.

[0028] Next an epoxy material is applied to the interior surface of the pipe. Preferably, a layer of epoxy is applied to the interior surface of the host pipe to the appropriate thickness. The epoxy can be spray, brush or roller applied. More preferably, the epoxy is applied using a machine such as a spincast machine that coats the walls of the pipe as it travels there along. The spincast machine has been described in detail in a co-pending application by the present inventor. The spincast machine has a rotary spray head that applies epoxy over the interior surface of the pipeline as the device is drawn out of the pipe

[0029] As the spincast machine travels along coating the pipe, the dry liner is inverted into the pipe directly behind and into the uncured wet epoxy coating. However, in the prior art when inversion is performed, pressure is applied to the liner and the liner spool is allowed to run freely. In this manner the liner quickly fills the interior of the pipe but as it does so it leaves air gaps at imperfections, joints and behind corners. The present invention limits pressure to preferably between 3-5 psi used of the initial inversion so as not to further damage fragile piping systems. In this manner the dry woven or needle punched liner tube is inverted into the host pipe. The liner tube will go into the host pipe in a dry, not wetted out condition.

[0030] To control the inversion process and coordinate with the installation of the spray applied epoxy, the speed of the spin caster is calibrated with the speed of the inversion system in order to feed the dry liner into the epoxy lined host pipe. Further a drag is set on the inversion equipment relative to the speed of the epoxy spinner unit. As seen in FIG. 2 the inversion system 20 has a motor 26 that is connected to the drum 34 that carries the liner 36. The motor via direct or indirect drive 28 regulates the speed at which the drum 34 can rotate thereby limiting the speed at which the liner 36 can be inverted into the pipeline. A computer controller 30 regulates the motor thereby controlling and limiting the inversion speed of the liner. It should be appreciated by one skilled in the art that the speed control of the drum may be accomplished by other means for controlling rotational speed such as brakes.

[0031] Once the liner is completely inverted into the pipeline, the internal pressure of the liner is slowly raised to a preferable range of about 8-10 psi. At this pressure, the dry inverted liner will be slowly infused into the uncured epoxy. The internal pressure in the inversion system will support the damaged pipe and force any excess resin through open pipe joints, cracks and bridge areas of the missing host pipe. In one example, the spincast line draws the spincast device through the pipeline applying a coating at about 4 linear feet per minute. The speed limited inversion liner is allowed to pay out at an inversion speed of approximately 0.5 feet per minute. The infusion tube will force the dry liner through the wet epoxy at a precise speed, pressure and controlled thickness. The slow rate of inversion will not allow air to be trapped behind the new liner and it will prevent twisting or binding when the new liner navigates bends and turns in the host pipe.

[0032] Once the process is complete, the inversion liner calibration tube (if employed) will be retrieved out of the system leaving the inversion liner as a stand-alone system. Preliminary testing shows the liner to have a flexural modulus in excess of 1,000,000 psi.

[0033] A new pipe within a pipe is thereby created by using potable water approved resins that can be cured under water with strong adhesion properties to wet under water substrates combined with woven structural fabrics such as carbon fiber and S glass structural fiberglass woven together. This process will make the host pipe 100 times plus stronger than it was when it was new, and stronger than any new pipe line product other than stainless steel or carbon steel pipe. The infusion liner will completely protect the water flowing within the pipe from free release into the water flow of any asbestos, lead PBCs or PVCs, and any surface ground water pollutants that may have previously entered through open pipe joints, cracks or breaks caused by the Venturi effect of flowing water.

[0034] This invention eliminates the need for wet out facilities, over the road transport of materials, and the need for steam or boiler trucks.

[0035] It can therefore be seen that the present invention provides a new and novel process for lining the interior surface of a pipeline to repair and salvage the pipe so that is can be used normally in a leak-free condition and provides a structural lining process that installs a sealing inner liner that is well suited to seal corner joints within a pipeline. For these reasons, the instant invention is believed to represent a significant advancement in the art, which has substantial commercial merit.

[0036] While there is shown and described herein certain specific structure embodying the invention, it will be manifest to those skilled in the art that various modifications and rearrangements of the parts may be made without departing from the spirit and scope of the underlying inventive concept and that the same is not limited to the particular forms herein shown and described except insofar as indicated by the scope of the appended claims.