Patent Application
20200263822
The invention described herein generally relates to a service reinforcement sleeve and method to soundly connect services conduits that are being rehabilitated using with a structural liner that uses the service reinforcement sleeve. This method and device are useful in situations where the conduit is in danger of eroding or has eroded around the service, and the service has mineral deposits, encrustation or tuberculation on its inside walls. The service reinforcement sleeve also addresses problems with the use of tube and flange devices when connecting services in situations where the service is at or near the top of the conduit.
Conduits for fluids, such as water or sewage conduits, or gas or chemical pipe, deteriorate over time. For example, many of the water mains throughout North America are made from unlined cast-iron pipe, the preferred material for water distribution systems up to the mid-1970's and beyond. Over time such pipes will deteriorate, often due to corrosion, becoming pitted and forming tubercules. This corroded material, in combination with mineral deposits, is known as encrustation and tuberculation.
Such deterioration results in leakage of the fluids, such as water or sewage, into the surrounding environment. For example, in 2013, Toronto experienced approximately 1700 water main breaks. These cause drops water pressure drops, and the leaking fluids can weaken the surrounding ground and can interfere with other underground systems, such as communication systems or other water or fluid bearing conduits. Such conduits need to be rehabilitated.
One approach to rehabilitation is to replace the deteriorated conduit. However, this can be a very costly and labour-intensive exercise; for example, if the conduit is a buried water pipe, replacement involves setting up a work area and digging up the pipe, known as “open-cut replacement”.
One solution is to deploy a cured-in-place structural liner within the conduit. For example, Canadian patent no. 2,361,960 of Mercier describes the use of a cured-in-place structural liner. The liner consists of two concentric tubular jackets (an outer and an inner jacket) made of a flexible material that are impregnated with an adhesive resin. Bonded to the inner surface of the inner jacket is a film that is impermeable to liquid to flow through the conduit. The liner is inserted into one end of a dry conduit and then pulled into place. A shaping step then occurs, where the liner is made to conform to the inner wall of the conduit. The liner is then cured in place by flowing heated water through the conduit. This causes the liner to become a rigid structure, bonded to the inner surface of the conduit.
In one example, such an approach results in a conduit lined with a polyurethane and fabric liner, typically 1/16 to ¼ of an inch thick, which is sealed in place with epoxy.
When rehabilitated conduits using a cured-in-place liner system, a goal is to create a “structural liner”—a liner that has sufficient structural and functional integrity that it will function as a replacement conduit even if the original conduit totally fails.
A related issue but increasingly prominent issue is erosion, crumbling and failure of the conduit around a service attached to the conduit. The attachment between a conduit and service puts stress on the conduit immediately around the service. Similarly, after a structural liner is installed, the attachment between a conduit and service puts stress on the conduit immediately around the service. It is desirable for a seal to be formed around the conduit that will prevent or minimize leakage even if the conduit fails around the service after the installation of the structural liner. It is also desirable to have a method to seal the service in cases where the conduit around the service has already failed before the installation of the structural liner. In either case, once the liner is inserted, inflated and cured, the cured-in-place liner is supposed to last for decades in constant use without failure and minimizing leakage.
Approaches and devices to assist in sealing connections between conduits and services, including in cases where there is a cured-in-place liner used. U.S. patent application Ser. No. 12/359,646 (pub. no. 2010/0187813) of Anders discloses a connector with a tubular member and an annular flange that is used to connect a lateral pipe to a main pipe. According to the abstract, the annular flange is glued to the inner surface of the main pipe and the tubular extends through an opening formed in the main pipe. PCT application no. PCT/GB00/00990 (pub. no. WO 00/55539) of Sanders discloses several sealing devices including a device with a hollow cylindrical bore and an annular part which is dished.
The invention in part involves a service reinforcement sleeve with a flange and a tubular section that can be used to bind a service to a liner with epoxy. This sleeve addresses the need to simultaneously be capable of remaining in the service until the epoxy cures in cases where there is no encrustation in the service, but also to be able to accommodate encrustation in the service, while attempting to minimize the distance between the sleeve and the inner walls of the service and the sleeve and the liner in order to promote a strong bond via the liner, sleeve and service via epoxy. In particular, minimizing the distance between the sleeve and the inner walls of the service and the sleeve and the liner reduces the possibility of voids in the epoxy, noting that such voids weakens the bond. The service reinforcement sleeve achieves this by employing flexible tabs (created by cutouts) at the end of the tubular section opposite the flange, where each tab has a lip.
The method of installation is designed to take advantage of the service reinforcement sleeve and increase the chances of a strong bond between the liner and service being formed. When lining a conduit, the service is typically first plugged in some manner with a plug, for example with a cork. Once the structural liner is in place and cured, the services are opened and the cork/plug removed, which leaves some cork/plug debris. The cork/plug debris is removed with a metal brush or similar device, which has at least three beneficial results: it creates a seat in the liner suitable for holding the flange of the service reinforcement sleeve; it cleans the service of encrustations at the lower end of the service which allows the service reinforcement sleeve to travel some distance up the service (during subsequent installation) before encountering encrustations; and it creates micro-abrasions in the lower end of the service which promote better bonding with epoxy. An insertion instrument is then used to insert a service reinforcement sleeve, covered with epoxy, into the service.
In accordance with the invention, there is provided a service reinforcement sleeve for bonding a service to a structural liner comprising: a tubular body having a first end and a second end opposite the first end, where the tubular body provides a conduit along which fluid may flow; a flange extending generally radially from the first end of the tubular body; at least three tabs defined by cutouts at the second end of the tubular body, where each tab has a lip extending generally radially from the end of the tab. In an aspect of this invention, the sleeve is made of stainless steel. In another aspect of this invention, the sleeve is made of a material with similar mechanical properties to stainless steel. In another aspect of this invention, the tabs are sized to enable sufficient binding to occur for the sleeve to remain in a service under the effects of gravity. In yet another aspect of this invention, the flange is an annular ring extending radially from the outer diameter of the first end. In a further aspect of this invention, the flange has a diameter of 31.3436 mm, a thickness of 0.7874 mm, the conduit formed by the tubular member has a diameter of 14.097 mm the tubular member has a length 21.1582 mm and a wall thickness of 0.762 mm, and there are four tabs defined by cutouts with a width of 5.3086 mm and a length 9.017 mm, and each lip has an extension of 0.381 mm and is located a distance 2.54 mm from the end of the tab. In a further aspect of this invention, the flange has a diameter of 31.3436 mm, a thickness of 0.7874 mm, the conduit formed by the tubular member has a diameter of 14.097 mm the tubular member has a length 21.1582 mm and a wall thickness of 0.762 mm, and there are four tabs defined by cutouts with a width of 5.3086 mm and a length 9.017 mm, and each lip has an extension of 0.381 mm and is located a distance 2.54 mm from the end of the tab, and this sleeve has an allowable deflection falls within the range of 0.221 mm to 0.381 mm. In a further aspect of this invention, the tubular body is embossed or roughened.
In accordance with this invention, there is also provided a method of bonding a service attached to a conduit to a structural liner installed in the conduit, comprising: locating the service and inserting a plug into the service; installing a structural liner; opening the service and removing the plug; using an abrading device to abrade the lower part of the service and the surrounding liner; preparing a service reinforcement sleeve which comprises: a tubular body having a first end and a second end opposite the first end, where the tubular body provides a conduit along which fluid may flow; a flange extending generally radially from the first end of the tubular body; and at least two tabs defined by cutouts at the second end of the tubular body, where each tab has a lip extending generally radially from the end of the tab; coating the tubular body and the flange with epoxy; inserting the service reinforcement sleeve into the service; and allowing the epoxy to cure. In an aspect of this invention, the plug is a cork. In another aspect of this invention, the structural liner is a cured-in-place liner. In another aspect of this invention, the step of using an abrading device to abrade the lower part of the service and the surrounding liner creates a seat in the liner around the service; and abrades a portion of the service nearest the structural liner. In yet another aspect of this invention, the step of inserting the service reinforcement sleeve into the service comprises inserting the sleeve so that the flange rests in the seat.
In accordance with this invention, there is provided a service bonded to a structural liner, comprising: a service reinforcement sleeve which comprises: a tubular body having a first end and a second end opposite the first end, where the tubular body provides a conduit along which fluid may flow; a flange extending generally radially from the first end of the tubular body; and at least two tabs defined by cutouts at the second end of the tubular body, where each tab has a lip extending generally radially from the end of the tab; the service being bonded to the tubular body; and the liner being bonded to the flange. In an aspect of this invention, the service is bonded to the tubular body by epoxy and the liner is bonded to the flange by epoxy. In another aspect of this invention, the flange is bonded to a seat that has been abraded into the liner.
The invention is illustrated in the figures of the accompanying drawings which are meant to be exemplary and not limiting, in which like references are intended to refer to like or corresponding parts, and in which:
Subject matter will now be described more fully hereinafter with reference to the accompanying drawings, which form a part hereof, and which show, by way of illustration, exemplary embodiments in which the invention may be practiced. Subject matter may, however, be embodied in a variety of different forms and, therefore, covered or claimed subject matter is intended to be construed as not being limited to any example embodiments set forth herein; example embodiments are provided merely to be illustrative. Those of skill in the art understand that other embodiments may be utilized and structural changes may be made without departing from the scope of the present invention. Likewise, a reasonably broad scope for claimed or covered subject matter is intended. The following detailed description is, therefore, not intended to be taken in a limiting sense.
Throughout the specification and claims, terms may have nuanced meanings suggested or implied in context beyond an explicitly stated meaning. Likewise, the phrase “in one embodiment” as used herein does not necessarily refer to the same embodiment and the phrase “in another embodiment” as used herein does not necessarily refer to a different embodiment. It is intended, for example, that claimed subject matter include combinations of example embodiments in whole or in part.
A typical conduit with a service that protrudes into the conduit is illustrated in
When rehabilitating conduits using a cured-in-place liner system, a goal is to create a “structural liner”—a liner that has sufficient structural and functional integrity that it will function as a replacement conduit even if the original conduit totally fails. An ongoing concern is dealing with the area around services that attach to the main conduit, which are subject to stress. There is an ongoing need for methods and associated devices to better connect structural liners to services given (a) the possibility that during the lifetime of the structural liner, the original conduit will fail in the area around the service, and (b) the possibility that the area of the original conduit around the service has already failed before the structural liner is emplaced.
The inventors have considered this problem, considering the following factors. First, the conduit, service and structural liner are all rigid. This has several implications, discussed below, and generally brings into question previous solutions that are designed for flexible services or conduits.
Second, the inside surface of the service may be become pitted, with mineral deposits and tubercules, known as encrustation and tuberculation forming in the service. For brevity, these are referred to in this description as encrustation.
Third, tubular devices with flanges inserted into services so that the flange rests against either the inner wall of the conduit or the inner wall of a structural liner often fall out before curing if the devices are inserted into services that have a core roughly perpendicular to the ground.
Further complicating such installations is the possibility of encrustation and tuberculation in the inside of the service 1. Conduits and services are commonly rehabilitated after decades of use, and some level of encrustation can be encountered. Recall that the service, conduit and structural liner are all rigid. As seen in
To address these concerns, a service reinforcing sleeve 10 as illustrated in
The use of cutouts 16 in a reinforcing sleeve or simple device 5 is disfavoured when connecting two conduits, or a conduit and a service, since the cutouts 16 generally promote the leakage of fluid around the cutout in the absence of epoxy.
In use, service reinforcing sleeve 10 is inserted into service 1. As seen in
In the case of encrustrations 7, as illustrated in
Note that the tabs 18 (defined by cutouts 16) flex independently of each other. This is advantageous, since in practical situations the encrustations 7 may be non-uniform—for example, there may be a significant encrustation on one side of the service while the opposite or adjacent sides are relatively clear. Using tabs 18 allows the service reinforcement sleeve to accommodate significantly non-uniform encrustations, as compared to simple tapering of the tubular body 12.
There are many embodiments of the service reinforcing sleeve 10, as the sleeve 10 should be sized to match the size of the service being reinforced. The dimensions of eight embodiments are listed in Tables 1 and 2. Table 1 gives the dimensions in inches, and Table 2 provides the same dimensions in millmetres. The top row of Tables 1 and 2 gives the nominal size of the service that the particular embodiment of sleeve 10 is designed to work with. A long and a short embodiment of the sleeve 10 is provided for each nominal size of the service, since the service may have been shortened before installation of the sleeve 10 (for example, if the service is damaged, the service may be ground to fix and/or shorten the service). Turning to
In all embodiments of Tables 1 and 2, the there are four evenly spaced cutouts 90 degrees apart.
The walls of tubular section 12 are: 0.030 inches (0.762 mm) for the 0.625 inch nominal diameter sleeves; 0.025 inches (0.641 mm) for the 0.750 inch nominal diameter sleeves; 0.031 inches (0.790 mm) for the 0.925 inch nominal diameter sleeves; and 0.034 inches (0.851 mm) for the 1.000 inch nominal diameter sleeves.
In another embodiment, service reinforcing sleeve 10 is made of stainless steel. In a more preferred embodiment, the stainless steel is AISI 316 grade due to its corrosion-resistant properties. However, as a general matter, any material can be used as long as it will provide similar mechanical properties to stainless steel.
The tabs 18 must have some elasticity or flexibility to allow the tabs to bend to accommodate encrustation, but must also be capable of pressing against the inner walls of service 1 to hold service reinforcement sleeve 10 in place in cases where there is no encrustation. The precise measurement of flexibility in a given configuration or size of service reinforcement sleeve 10 depends on (i) the elastic modulus of the material, (ii) the density of the material, and (iii) the coefficient of friction between the material of the inner service wall and the sleeve. For example, for the embodiment of sleeve 10 described above for the 0.75 inch service configuration, the allowable deflection to ensure that the sleeve 10 will remain in the service until curing of the epoxy falls within the range of 0.221 mm to 0.381 mm. (“allowable deflection” means the distance the tab can physically bend from its unloaded state when inserted into a service without encrustation and still apply sufficient friction force to keep the sleeve in the service) The allowable deflection may be calculated for each configuration of the sleeve (corresponding to different service sizes).
As a further embodiment, the sides 22 of service seal 10 may be embossed, as illustrated in
The strength of the bond between the service seal 10 and the service 1 is related to the surface area of side 22 that is bonded with epoxy to the inner wall of service 1. Generally, the longer the tubular body 12 below the cutouts 16 (thus increasing area 22), the stronger the bond with the service 1. As a practical matter, service reinforcement sleeve 10 cannot pass beyond the ball valve in the service, so the length of the service reinforcement sleeve 10 is limited in any real application.
To describe a method of creating a bond between a service 1 and a liner 3 using service reinforcement sleeve 10, we begin with
The conduit 2 is then lined with a structural liner, for example by installing a cured-in-place liner. The liner 3 is then cut or otherwise removed to open service 1, and the plug or cork or other blockage 30 is removed. As seen in
Turning to
Turning to
As an optional additional step in the method, in cases where the encrustation makes it difficult to insert service reinforcement sleeve 10, one or more of the tabs 18 may be physically bent towards the central axis of the tubular body 12. To better allow this step, in a preferred embodiment there are four tabs spaced 90 degrees apart, since this makes it easier for an operator orient the bent tabs for insertion around the difficult encrustation. As a generally matter, a service reinforcement sleeve may have three or more tabs, which may of may not be evenly spaced around the circumference of tubular body 12. Two tabs is disfavoured, since such a sleeve would tend to rock or tilt after installation.
Overall, the use of the described method and service reinforcement sleeve 10 result in a greater likelihood of a stronger bond between service 1 and liner 3.
The epoxy used in the method described above and more generally in connection with the use of the service reinforcement sleeve 10 needs to be an epoxy that will cure over a practical time period without the use of heat or another hardening factor. Ideally it should also be viscous enough to facilitate the installation of service reinforcement sleeve 10 without too much loss of epoxy.
It should be noted that service reinforcement sleeve 10 can be used to advantage to connect a liner 3 to a service 1 even if the step of abrading the debris from a cork and creating a seat is not performed. However, in such situations there is a possibility that the service will have encrustations in area 34 (as seen in
The method above describes using a metal brush to abrade away debris 32, create seat 36 and micro-abrade area 34. A person skilled in the art will realize that other methods of abrasion or scouring may be used with the same effect.
The purpose of establishing a strong bond between service 1 and structural liner 3 (via epoxy and service reinforcement sleeve 10) is to render conduit 2 of less importance, to the extent that service 1 and structural liner 3 should continue to robustly function even if conduit 2 completely fails in the area of service 1 or if conduit 2 had failed in the area of service 1 even before the installation of the structural liner. In
In the present specification, an embodiment showing a singular component should not necessarily be limited to other embodiments including a plurality of the same component, and vice-versa, unless explicitly stated otherwise herein. Moreover, applicants do not intend for any term in the specification or claims to be ascribed an uncommon or special meaning unless explicitly set forth as such.
It is to be understood that the phraseology or terminology herein is for the purpose of description and not of limitation, such that the terminology or phraseology of the present specification is to be interpreted by the skilled artisan in light of the teachings and guidance presented herein, in combination with the knowledge of one skilled in the relevant art(s).
