Patent Application
20080072982
This invention relates to a reusable inversion sleeve assembly for installing a cured in place liner with an apparatus having at least one rigid gland. The methods and apparatus reduce the time needed to set up a wet out cured in place liner for installations using air for inversion and steam for curing and use of a dual gland apparatus allowing use of a hold back strap and a lay flat hose for introduction of steam.
It is generally well known that conduits or pipelines, particularly underground pipes, such as sanitary sewer pipes, storm sewer pipes, water lines and gas lines that are employed for conducting fluids frequently require repair due to fluid leakage or deterioration. The leakage may be inward from the environment into the interior or conducting portion of the pipelines. Alternatively, the leakage may be outward from the conducting portion of the pipeline into the surrounding environment. In either case, it is desirable to avoid this leakage.
The leakage may be due to improper installation of the original pipe, or deterioration of the pipe itself due to normal aging or to the effects of conveying corrosive or abrasive material. Cracks at or near pipe joints may be due to environmental conditions such as earthquakes or the movement of large vehicles on the overhead surface or similar natural or man made vibrations, or other such causes. Regardless of the cause, such leakage is undesirable and may result in waste of the fluid being conveyed within the pipeline, or result in damage to the surrounding environment and possible creation of a dangerous public health hazard. If the leakage continues it can lead to structural failure of the existing conduit due to loss of soil and side support of the conduit.
Because of ever increasing labor, energy and machinery costs, it is increasingly more difficult and less economical to repair underground pipes or portions that may be leaking by digging up and replacing the pipes. As a result, various methods had been devised for the in place repair or rehabilitation of existing pipelines. These new methods avoid the expense and hazard associated with digging up and replacing the pipes or pipe sections, as well as the significant inconvenience to the public. One of the most successful pipeline repair or trenchless rehabilitation processes that is currently in wide use is called the Insituform® Process. This Process is described in U.S. Pat. Nos. 4,009,063, 4,064,211 and 4,135,958, all the contents of which are incorporated herein by reference.
In the standard practice of the Insituform Process an elongated flexible tubular liner of a felt fabric, foam or similar resin impregnable material with an outer impermeable coating that has been impregnated with a thermosetting curable resin is installed within the existing pipeline. Generally, the liner is installed utilizing an eversion process, as described in the later two identified Insituform patents. In the eversion process, radial pressure applied to the interior of an everted liner presses it against and into engagement with the inner surface of the pipeline. However, the Insituform Process is also practiced by pulling a resin impregnated liner into the conduit by a rope or cable and using a separate fluid impermeable inflation bladder or liner that is everted within the liner to cause the liner to cure against the inner wall of the existing pipeline. Such resin impregnated liners are generally referred to as “cured-in-place-pipes” or “CIPP liners” and the installation is referred to a CIPP installation.
The CIPP flexible tubular liners have an outer smooth layer of relatively flexible, substantially impermeable polymer coating the outside of the liner in its initial state. When everted, this impermeable layer ends up on the inside of the liner after the liner is everted during installation. As the flexible liner is installed in place within the pipeline, the pipeline is pressurized from within, preferably utilizing an eversion fluid, such as water or air to force the liner radially outwardly to engage and conform to the interior surface of the existing pipeline.
Typically, an eversion tower is erected at the installation site to provide the needed pressure head to evert the liner or a bladder. Alternately, an eversion unit as shown and described in U.S. Pat. No. 5,154,936, No. 5,167,901 (RE 35,944) and No. 5,597,353, the contents of which are incorporated herein by reference. Cure may be initiated by introduction of hot water into the everted liner through a recirculation hose attached to the end of the everting liner. Inversion water is recirculated through a heat source such as a boiler or heat exchanger and returned to the inverted liner until cure of the liner is complete. The resin impregnated into the impregnable material is then cured to form a hard, tight fitting rigid pipe lining within the existing pipeline. The new liner effectively seals any cracks and repairs any pipe section or pipe joint deterioration in order to prevent further leakage either into or out of the existing pipeline. The cured resin also serves to strengthen the existing pipeline wall so as to provide added structural support for the surrounding environment.
The eversion tower, which was time consuming to construct, caused workers to be 30 feet above the ground often near trees and electrical wires. This method was improved by an apparatus, which allowed Insituform to create a hydraulic head by the use of a sphincter valve. The liner was fed into the top of the apparatus and pulled through the sphincter valve by pressurized water below the valve. The pressurized water applied a force on the nose of the liner causing it to invert into the pipe being rehabilitated. These apparatuses for the rehabilitation of small diameter pipe have been in use for about fifteen years.
The major disadvantage to the use of these apparatuses with water is the quantity and availability of the inverting water. Water must be heated typically from 55° F. to 180° F. in order to affect the cure, and then cooled by the addition of more water to 100° F. before being released to an acceptable disposal system.
This disadvantage may be overcome by using air in lieu of water to create the inverting force. Once the impregnated liner is fully inverted, it then can be cured with steam. Although water is necessary to produce steam, the quantity of water in the form of steam is only 5-10% of that required for water inversion, cure and cool down. This means that steam can be used for curing even if water is not readily available on site. This drastic reduction in the quantity of water is the result of the higher energy available from one pound of water in the form of steam versus one pound of heated water. One pound of steam condensing to one pound of water gives off approximately 1000 BTUs while one pound of water gives off only one BTU for each degree in temperature drop. This reduced water requirement plus virtual elimination of the heat up cycle greatly reduces cure cycle and installation time.
With this apparent advantage in using air inversion and steam cure why has the industry been slow to abandon water inversion and hot water cure?
When water is used to invert the resin-impregnated liner, the uninverted portion of the liner from the inverting nose to the inverting apparatus is buoyed up by a force equal to the quantity of water displaced by the liner. In the case of CIPP liners, this mean the effective weight of the liner is substantially reduced, as is the force necessary to pull the uninverted liner forward to the inverting nose. When air is used to create the inverting force, the uninverted liner lies on the bottom of the pipe and the air pressure acting on the inverting nose of the liner must pull the full weight of the liner forward.
Three forces must be over come to invert a CIPP liner no matter what is used to create the inverting energy. These forces are:
Force number one (1) above is generally the same for both air and water inversions.
Force number two (2) varies greatly between air and water and can limit the length of air inversions. There is limit on how much pressure can be used to invert a liner without adversely affecting the quality of the installed CIPP liner and/or damaging to the existing conduit. Lubricant can be used for both water and air inversion to reduce the required pulling force.
Force number three (3) can vary based on the apparatus design. In most apparatus presently in use, the force required to pull the liner through the apparatus will increase when either or both forces one and two increase. This is caused by the fact that in order to increase available inversion energy, typical apparatus in use today restrict loss of pressurized fluid from the pressure chamber below the liner entry point into the apparatus and the cuff and banded end of the liner being inverted. This restriction is typically accomplished by increasing the air pressure in a pneumatic sphincter gland, or by using a gland that is energized by the inverting fluid. The movement inward in typical cases is restricted by the gland material and compression of the inverting CIPP liner. This in turn causes an increase on the friction between the inverting CIPP liner and gland.
In view of these apparent benefits of steam cure compared to hot water cure, the use of steam has been proposed in view of the energy it carries. Air invert an inflation bladder and flow-through steam to cure has been disclosed in Insituform U.S. Pat. No. 6,708,728 and No. 6,679,293, the contents of which are incorporated herein by reference. The processes disclosed in these recently issued patents utilize pull in and inflate technology and are currently in use for small diameter liners. They provide advantages over water eversion for small diameters. However, the process described does not provide for use of a lay flat hose for introduction of steam. Moreover, use of a puncturing canister disclosed in these patents is not suitable for medium and large diameter liners. Generally, medium size liners are considered to be those between about 18 and 36 inches in diameter. Large diameters are those in excess of about 42 inches and larger in diameter.
Accordingly, it is desirable to provide improvements to reduce the efforts needed to prepare a CIPP liner for installation using an apparatus having at least one selectively operable rigid gland for introduction of air for inversion without having to deflate the liner prior to injecting steam for curing.
Generally speaking, in accordance with the invention, an inversion sleeve assembly for installation of a cured in place liner with a rigid gland apparatus is provided. The inversion sleeve assembly includes a tubular flexible sleeve and a cylindrical banding boot having an inlet port for introducing inversion and/or curing fluid at the distal end of the sleeve. The sleeve and the inversion boot are of the same dimension as the cured in place pipe liner to be inverted. The assembly is used with an installation apparatus having a frame with at least one selectively operable rigid gland upstream of the banding boot. The sleeve passes between a rigid gland used to form a fluid seal. The flexible inversion sleeve may have an installed curing fluid inlet for use with an apparatus having two rigid glands. In this case, the inlet on the sleeve is located between the two glands with the banding boot downstream of the lower gland. In a preferred embodiment the flexible sleeve is a length of dry cured in place liners of the same dimension as the liner being installed. The sleeve has at least one layer of impregnated material and an outer impermeable layer. The impregnable material holds lubricant to aid in the installation and the sleeve assembly is reusable.
A resin impregnated liner is fed through the flexible inversion sleeve and banding boot, turned back and banded about the banding boot prior to being inverted into the existing conduit. Selective opening and closing of the glands in a dual gland apparatus allows passage of a hold-back cable or strap to control the speed during the second half of the inversion and passage of a lay flat hose and steam fitting for introduction of heated air or steam during cure. Use of a perforated lay flat hose for steam cure allows for introduction of steam along the entire length of the inverted liner to avoid the consequences of accumulation of condensate that often leads to poorly cured sections of liner in steam cure processes. The dual glands allow for the lay flat hose with steam attachment to pass through the frame and into the inverted liner without deflating the liner prior to introduction of curing fluid. Preferably, the lay flat hose has alternating holes formed along its length near the edge. Typically, this is ¼ to 1½ inches from the edge of the lay flat hose. This is to insure distribution of steam at the bottom along the full length of the liner regardless of the orientation of the hose. Once the inversion is stopped, a porting drill or forming device may be used to form an exhaust port with an adjustable exhaust hose. Steam is introduced into the liner through the lay flat hose to cure the resin without allowing the inverted liner to deflate.
Accordingly it is an object of the invention to provide an improved reueable sleeve assembly for use with a rigid gland apparatus for installing a CIPP liner.
It is another object of the invention to provide an inversion sleeve with installed fluid(s) inlet for use with a rigid gland apparatus for inverting a CIPP liner with air and curing with steam.
It is another object of the invention to provide an improved method for air inversion and steam cure of a CIPP liner with an apparatus having rigid dual glands.
It is a further object of the invention to provide an improved method wherein a cured in place pipe liner is inverted with air and cured with steam without deflating the liner after being positioned within the existing conduit.
Yet another object of the invention is to provide a method and apparatus suitable for air inversion and steam cure wherein the liner is inverted through a segment of liner formed with at least one port for introduction of air and/or steam.
Still another object of the invention to provide an improved method of air inversion of a CIPP liner with a holdback strap and lay flat hose for introduction of steam to cure the liner.
Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification.
The invention accordingly comprises the several steps and the relation of one or more of such steps with respect to the others, and the apparatuses possessing the features, properties and relation of elements which are exemplified in the detailed disclosure and the scope of the invention will be indicated in the claims.
For a fuller understanding of the invention, reference is had to the following description taken in connection with the accompanying drawings in which:
FIGS. 6(a) and 6(b) illustrate an exhaust porting technique.
An improved method and apparatus for air inverting and steam curing a CIPP liner in compliance with ASTM F1216 Standard Practice for Rehabilitation of Existing Pipelines and Conduits by the Inversion and Curing of a Resin-Impregnated Tube is described. The method and apparatus described herein are well suited for the installation of medium diameter CIPP liners working from the surface through structures, such as manholes to rehabilitate existing buried pipelines and conduits.
An inverting apparatus 11 having a single rigid lower gland 21 constructed and arranged in accordance with the invention is shown in
Apparatuses 11 and 11a are rigid frames dimensioned to be positioned over the inverting access to the conduit to be lined. Apparatuses 11 and 111 are fabricated from metal bars or tubes to form a frame 12 having a sufficient width “w” to receive a flattened cured in place pipe liner to be installed. Frame 12 is substantially rectangular in the illustrated embodiment and has a rectangular entry opening 13 with a plurality of hooks 14 to secure a flexible inversion sleeve 207 as shown in
Frame 12 has a height “h” sufficient to support sleeve 207 and a banding boot 211 secures to the bottom of sleeve 207. In the dual gland unit of
In
In the illustrated embodiment of
Air cylinders 24 and shown mounted above lower gland 21. Each cylinder is connected to a coupling so that runs on a pair of linear guide bearings.
In
The rigid cooperating opposed faces of members 22 and 23 of lower gland 21 may be flat. Curvature may be added to the mating surfaces by welding a small diameter pipe to beams 22 and 23 or by using tubes or pipes for member 22 and 23. This curved surface provides a smoother surface for engaging the inverted liner.
Lower gland 21 forms the air seal during air inversion in both apparatus 11 and 11a. During the start and first half of the inversion, lower gland 21 is closed to a distance apart of about four times the thickness of the liner by use of a gap setting device. This device may be appropriately sized spacers placed on guide hearings 20a and 20b. Once the holdback strap and lay flat hose pass through lower gland during the second half of the inversion, the gap of lower gland 21 is reduced to about twice the liner wall thickness.
By utilizing this construction, an increase in inverting air pressure will cause the liner to invert without requiring an increase in pressure on the liner at lower gland 21 by members 22 and 23. Air pressure to cylinders 24 may be increased to prevent gland 21 from opening to a gap more than twice the liner thickness. The gap adjustment device, such as spacers placed on guide bearings or threaded bolts prevent a reduction of the gap beyond that desired.
A fluid inlet port 209 for introduction of air and/or steam is formed at an appropriate location along the length of the sleeve 207. Port 209 provides access to the interior of sleeve 207 wherein resin impregnable layers 223 face each other. A banding boot 211 formed of a substantially rigid cylindrical wall 212 is formed with a fluid inlet port 213. Ribs 214 and 216 are formed at each end of cylindrical sidewall 212. This allows banding folded end 206 of sleeve 207 to ribs 214 to complete construction of an inversion sleeve 201 assembly as illustrated in
By utilizing a double thickness of a section of cured in place pipe liner 202 as inversion sleeve 207, this provides increased dimensional stability. In additional to utilizing a standard coated resin impregnable section of liner, reinforcement in the weft and/or warp direction of an impregnable material may be included. Alternatively, helical reinforcement elements may be utilized or a reinforced coating such as a reinforced coated scrim providing increased strength in both the warp and weft direction may be used to provide additional dimensional stability to sleeve 202 during the inversion and cure.
Folded edge 208 is retained so as to provide additional stability after banding at ribs 214. By utilizing this construction, lubricant can be added to interior impregnable layer 223 of inversion sleeve 207. This allows inversion sleeve 207 to be utilized for several installation.
The seal around liner 200 to be installed is created by sleeve 207 of the identical profile and dimension. Thus, it is not necessary to be concerned about forming a seal at the edges of the flattened liner. The length of the edge perimeter of the flattened liner is minimal compared to the long sides of the flattened liner so that stress on the edges are minimal and no addition closure or support at the edges is needed. This allows use of straight rigid tubes or beams to form the gland and seal. The process and apparatus disclosed provide an advantage over prior art inversion devices. In these latter devices forming a seal at the edges is difficult because the inversion commences downstream of the seal or gland. Here, there is an advantage due to the fact that the inversion of the liner has commenced before the liner passes through a gland for forming an inversion and curing seal.
The first half of an inversion with apparatus 11a is shown in schematic in
When upper gland 16 is open, lay flat hose 112 is cut above upper gland 16 and a steam hose is attached to the cut end through port 209 with a flexible layflat adapter attached to layflat hose 112 and inserted into air/steam port 209 to facilitate the addition of steam to inverted liner 200. The layflat adapter may be a thin tubular rigid bendable metal sleeve with a flared profile which prevents it from being pulled into the air/steam port. The tubular portion of the sleeve is inserted into the cut end of the lay flat and inserted into the inlet port. The lay flat hose is then engaged between the flared region of the sleeve and the port. The slack in lay flat hose 112 will drop into the invert when upper gland 16 is closed and lower gland 21 opened at the start of the steam cycle as shown in
Referring now to
The orifice pattern described provides more steam at the proximal end of liner 200 and ensures good mixing even if hose 112 becomes twisted. This also insures that steam is injected into any condensate that forms in the pipe invert to cure that portion of the resin in the liner covered by the condensate pool. Steam is provided from a steam inlet hose 109 that is regulated by a valve manifold. The steam flow is adjusted to maintain a curing pressure of about 3-6 psi until cure cycle is complete.
Knowing the physical properties of the CIPP liner (diameter, length, thickness, resin and catalyst system) and available boiler output in BTUs per hour permits the adjustment of orifice size to match boiler output in pounds of steam per hour with recommended cure cycle time.
It can readily be seen that the process in accordance with the invention readily allows one to attain the advantage of curing a resin liner with flow through steam. By practicing the process, a tubular member can be easily inverted through an existing pipeline. Providing an apparatus having two rigid glands allows an inverting liner to be installed with a hold back strap and lay flat hose. Use of gap setting devices to maintain the gap at the lower gland allows for increasing eversion pressure to be applied to the complete profile of the liner without increasing the gland pressure on the inverting liner. Steam is then passed into the inverted liner to utilize the higher energy available in the steam that significantly shortens the cure cycle when compared to hot water cure.
It will thus be seen that the objects set fort above, among those made apparent from the preceding description, are efficiently attained and, since certain changes may be made and carrying out the above method and in the construction set forth without departing from the spirit and scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.
It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention which, as a matter of language, might be said to fall there between.
This application is based on and claims the benefit of co-pending provisional application Ser. No. 60/840,818, filed Aug. 29, 2006, the contents of which is incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 60840818 | Aug 2006 | US |
