Abstract:
A liner assembly for a manhole or passage comprises a multiple-ply, generally cylindrical tube. The outermost ply includes inner and outer surfaces and is adapted for being impregnated with material for rigidifying and bonding the outer surface of the outermost ply to a manhole or passage. The innermost ply includes inner and outer surfaces and is adapted for being impregnated with a material for rigidifying the innermost ply. An impermeable ply is disposed between the innermost and outermost plies. The impermeable ply includes an impermeable membrane having fibers impregnated on the inner and outer surfaces of the impermeable ply. The fibers of the inner surface of the impermeable ply bond with the epoxy impregnated outer surface of the innermost ply. Likewise, the fibers of the outer surface of the impermeable ply bond with the epoxy impregnated inner surface of the outermost ply, so that the manhole or passage becomes structurally reinforced.

Description:
This is a continuation of Ser. No. 08/897,965 filed on Jul. 22, 1997, now U.S. Pat. No. 5,915,886. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to an improved liner for rehabilitating pipes, passages, and manholes. In particular, the present invention relates to a multiply internal lining for an eroded or damaged pipe, manhole, or passageway, in which a felt impregnated vinyl ply is mechanically locked to inner and outer resin hardened fiberglass plies. 
     BACKGROUND OF THE INVENTION 
     Waste water is transported through a system of conduits, known as sewers, from the point of generation to a remote treatment or disposal site. Frequently, the exposed surfaces become deteriorated, resulting in undesirable leakage and difficulty with the flow of the fluid. The sewers are typically provided with a vertically disposed manhole. The manhole has an opening at the surface or grade level. The lower or invert end of the manhole has a flow path, known as a lateral, through which sewage flows on its way to the treatment plant. The manhole may be formed of cement, concrete or brick, and typically has an internal diameter many times greater than the diameter of the flow path of the lateral. 
     The sewage may generate an atmosphere which is damaging to the mortar with which a brick manhole is formed. Alternatively, the environment may be damaging to the cementitous material used in manufacturing the manhole. Should the manhole be damaged, then rainfall or surface water may enter the manhole, thereby overloading the sewage system and potentially causing untreated sewage to be discharged into streams, lakes, and the like. Preserving the structural integrity of manholes is one means of minimizing the load applied to a sewage pumping treatment plant. These problems also apply to sewage stations, which are located along the sewage collection system, and which may also require rehabilitation. 
     In the past, systems have been developed to rehabilitate or repair damaged manholes. For instance, my prior U.S. Pat. No. 5,265,981, the disclosure of which is incorporated herein by reference, discloses a system and method for rehabilitating a manhole. In that system, inner and outer fiberglass plies sandwich a middle impermeable ply. The outer ply is adapted for being impregnated with a material which rigidities the outer ply to the manhole. The middle ply is impermeable and prevents fluid from seeping into the manhole. The inner layer is also impregnated with a material which rigidifies the inner layer, so that the manhole becomes structurally reinforced. My prior U.S. Pat. No. 5,490,744, the disclosure of which is incorporated herein by reference, discloses a method and apparatus for inflating and curing a resin impregnated manhole liner. 
     My above described patents constituted a significant and advantageous improvement in the art. However, further improvement is virtually always possible in any field of endeavor, which turned out to be true here. For example, because the middle ply is made from an impermeable material, it is slick and may not always bond well to the epoxy impregnated inner and outer plies. Thus, while the manhole is structurally reinforced, there still remains a risk of the inner reinforced layer prying loose. 
     Thus, there is a need in the art for a liner for sealing and reinforcing a manhole, in which an impermeable middle layer is structurally bonded with the inner and outer plies, providing extra structural reinforcement. 
     SUMMARY OF THE INVENTION 
     A principal object of the present invention is to provide a liner for sealing and reinforcing a manhole which provides extra structural reinforcement to the manhole. 
     The above object is achieved according to the present invention. 
     A liner assembly for sealing and reinforcing a manhole is provided. The assembly includes a multiple ply contoured tube having first, second, and third oriented plies. The first ply includes inner and outer surfaces for being impregnated with a material for rigidifying and binding the outer surface of the first ply to the interior of the manhole. The third ply includes inner and outer surfaces for being impregnated with a material for rigidifying the inner surface of the third ply, so that the interior of the manhole is structurally reinforced. The second ply is impermeable to fluids, and is disposed between the first and third outermost plies. The second ply includes an impermeable membrane having fibers impregnated on inner and outer surfaces of the second ply, but not penetrating the membrane. The outer surface of the second ply is bonded to the inner surface of the first ply, and the inner surface of the second ply is bonded to the outer surface for the third ply. The liner assembly includes means for securing the outermost, innermost, and impermeable plies together, so that the plies are facially oriented. 
     A rehabilitated manhole is provided. The manhole includes a vertically disposed manhole having an upper end, internal walls, and a lower end with at least one lateral. A reinforcing system is positioned within the manhole. The reinforcing system includes a support tube assembly comprising first, second, and third juxtaposed layers, with the first and third layers formed from a woven, structural material. The second layer is disposed between the first and third layers, and is formed from a membrane impermeable to fluids and has fibers impregnated on its first and second surfaces, but not penetrating through the membrane. Each of the first and third layers is impregnated with an epoxy resin system, so that the first and third layers are rigidified and the third layer is bonded to the internal walls and lower end of the manhole. In addition, the fibers on the first surface of the second layer are bonded to the inner surface of the third layer, and the fibers on the second surface of the second layer are bonded to the outer surface of the first layer. Each of the layers is cut proximate to the lateral for permitting access thereto. 
     These and other objects and advantages of the invention will be readily apparent in view of the following description and drawings of the above described invention. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     The above and other objects and advantages and novel features of the present invention will become apparent from the following detailed description of the preferred embodiment of the invention illustrated in the accompanying drawings, wherein: 
     FIG. 1 is a schematic view of the liner assembly of the invention; 
     FIG. 2 is a cross-sectional view of the preferred embodiment of the second ply of the present invention; 
     FIG. 3 is a cross-sectional view of the preferred embodiment of the second ply as it is used according to the present invention; 
     FIG. 4 is a cross-sectional view of an alternative embodiment of the second ply as it is used according to the present invention; 
     FIG. 5 is an elevational view, partially in section, illustrating the liner assembly of FIG. 1 being positioned within a manhole; and 
     FIG. 6 is an elevational view, partially in section, of the manhole of FIG. 5 after the liner assembly has been inflated. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Liner assembly L, as best shown in FIG. 1, is a generally cylindrical tube comprised of plies or layers  10 ,  12 , and  14 . An inflation bladder  16  overlies the ply  14 , but is selectively removable therefrom. The liner assembly L has an open end  18  and an opposite closed end which has a contoured cut  20  therein. 
     The liner assembly L is formed from a plurality of plies  10 ,  12 , and  14  which are facially disposed in the order named. Respective edges of the plies are secured together, such as by stitching  15  with a double needle machine, in order to create the generally tubular configuration of the liner assembly L. The stitching also serves to maintain the plies  10 ,  12 , and  14  in their facially disposed orientation during fabrication of the liner assembly L and its subsequent installation. While the liner assembly L is disclosed as being cylindrical, it may have whatever shape is called for by the structure to be rehabilitated. 
     The plies  10  and  14  are both formed from a woven structural-type fiberglass, such as disclosed in my prior cited U.S. Pat. No. 5,265,981. I prefer that the fiberglass be a 24 oz. woven roving, in order to provide adequate structural integrity for the use to which the liner assembly L is to be put. 
     The ply  12 , on the other hand, is a composite fabric, and is best illustrated with reference to FIGS. 2,  3 , and  4 . With reference in particular to FIG. 2, ply  12  includes a nonporous inner membrane  12   a  sandwiched between outer layers of fiber  12   b  and  12   c . The inner membrane is impermeable to water, gas, and chemical attack, which provides strength to the liner assembly L during manufacture and installation, and also prevents migration of water, gas, and chemicals from the ply  10  to the ply  14 . In the preferred embodiment, the inner membrane  12   a  is a polyester fabric, coated with polyvinyl chloride, so that the polyester fabric is encased in a vinyl blanket forming the membrane. The outer fiber layers  12   b  and  12   c  are polyester felts, which is impregnated or impressed onto the outer surfaces of the inner membrane  12   a  to be mechanically connected thereto. The felt fibers of layers  12   b  and  12   c  do not penetrate inner membrane  12   a , so ply  12  retains its impermeable quality. A suitable composite material for the ply  12  may be purchased from the Hartz Corporation. The ply  12  has a thickness of 2.77 mm, greater than that of plies  10  and  14 . The base polyester fabric  12   a  has a weight of 4.0 oz/yd 2 . 
     Each of the plies  10  and  14  is impregnated with an epoxy resin system prior to installation of the liner assembly L. The epoxy resin system causes the fiberglass layers  10  and  14  to be rigidified after being cured, while being mechanically bonded also to the ply  12 . The resin impregnated plies  10  and  14  mesh with the outer fiber layers  12   b  and  12   c  of ply  12 , causing the epoxy resin to be absorbed onto the outer fiber layers  12   b  and  12   c . When the resin is cured, the fibers of layers  12   b  and  12   c  of ply  12  become mechanically bonded with the resin impregnated plies  10  and  14 , forming a strong bond between the plies. 
     With reference to FIG. 3, outer fiber layers  12   b  and  12   c  of ply  12  provide a mechanical connection to the plies  10  and  14  after the resin hardens, bonding an outer fiber layer  12   b  of ply  12  to outer ply  10 , and the outer fiber layer  12   c  to the inner ply  14 , securely together. Thus, because inner ply  14  and ply  12  are mechanically connected, the risks of prying ply  14  from ply  12 , and rupturing ply  12 , are significantly reduced. To increase the strength of the bond between the plies, the thickness of the felt of layers  12   b ,  12   c  can be increased or varied. The thicker the felt, the stronger the bond will be between the plies. In addition, the epoxy resin system causes the ply  10  to be bonded to the surrounding walls of the manhole, thereby providing structural support for the manhole because the epoxy resin system fills the openings left by damaged or removed mortar, or the like. 
     The epoxy resin system  22  may be applied to the liner assembly L through a roller  24   5  which spreads the resin system  22  over the plies  10  and  14 . Each of the plies  10  and  14  should be thoroughly impregnated by resin  22 . In practice, the outer two layers of the liner assembly L are peeled back, much like socking and unsocking two tube socks, and the resin is initially applied to the ply  14 , after which the bladder  16  is then applied. The liner assembly L is then realigned with the interior fiberglass layer and the inflation bladder, and the epoxy resin system  22  then applied to the ply  10 . I prefer that the plies  10  and  14  be impregnated with a two component epoxy system, such as disclosed in my prior cited U.S. Pat. No. 5,265,981 and U.S. Pat. No. 5,490,744. 
     In an alternative embodiment, the outer fiber layers  12   d  and  12   e  are of differing thicknesses, as illustrated with particular reference to FIG.  4 . In FIG. 4, the outer fiber layer  12   e  of ply  12  is thicker than the outer fiber layer  12   d  of ply  12 . The thicker layer  12   e  provides a stronger bond between ply  12  and inner ply  14 , than the bond formed between layer  12   d  and ply  10 . While it is important to have a strong bond between both ply  12  and ply  10  and ply  12  and ply  14 , a stronger bond may be desired between ply  12  and ply  14 , because ply  14  is directly exposed to the damaging environment of the sewage system. However, it should be understood that outer layers  12   d  and  12   e  may be of any thickness, as is desired. 
     Once the liner assembly L has been manufactured, its layers are impregnated with the epoxy resin, and it is lowered into the manhole M. Manhole M, as best shown in FIG. 5, is a brick manhole which has bricks  26  secured together by mortar  28 . The faces  30  of the bricks  26  have become irregular due to the damaging environment to which the faces  30  have been exposed. Likewise, the mortar  28  also has been damaged or removed by the environment, with the result that the bricks  26  are spalling and/or being loosened and removed. 
     Liner assembly L is adapted and designed to reinforce the manhole M while permitting the sewer pipes  40  and  42  to remain in service. It can be seen in FIG. 5 that a crane (not shown) has a cable  53  to which a hook  54  is attached for connection to bracket  52  of lifting assembly  50  secured to flange  48  by bolts. Collar  46  may be used to secure the liner assembly L to the neck  42 . 
     Use of the liner L of FIG. 1 for rehabilitation of the manhole M of FIG. 5 proceeds relatively quickly, requiring only a few hours for preparation of the liner assembly L. 
     Prior to beginning rehabilitation of the manhole M, I have found it desirable to take measurements or to review accurate blueprints so that the liner assembly L may be fabricated to substantially correspond to the contour of the manhole M. Although I have illustrated the manhole M and its corresponding liner assembly L as being generally cylindrical in configuration, those skilled in the art will appreciate that the manhole M may have any shape. The liner assembly L is manufactured to substantially correspond to the configuration and at least the size of the manhole M, thereby substantially eliminating any gapping which could occur between the liner assembly L and the surfaces of the manhole M. I have found that the liner assembly L can be appropriately fabricated by conventional sewing techniques, and the stitching  15  resulting from those techniques achieves the added benefit of securing the plies  10 ,  12 , and  14  together. Each of the plies  10 ,  12 , and  14  is normally rectangular in plan, so that the liner assembly L requires that respective edges of the plies be secured together, preferably by double needle stitching, in order to create the tubular configuration of FIG. 1, or whatever other configuration may be required to match the contour of the manhole M. Additional stitching may also be provided as necessary. 
     After the liner L has been appropriately positioned within the manhole M, then the assembly L is pressurized with heated air, as disclosed in my prior cited references U.S. Pat. Nos. 5,265,981 and 5,490,744. This causes the liner assembly L to inflate and contact the walls of the manhole M to cure the resin system impregnating the plies  10  and  14 . 
     FIG. 6 illustrates the liner assembly L when positioned within the manhole M and after having been inflated with pressurized heated air. It can be seen in FIG. 6 that the liner assembly L and the resin system impregnating the ply  10  intimately engage the exposed faces  30  of the bricks  26 , and also permit the laterals  40  and  42  to be preserved. The intimate engagement of the ply  10  and its impregnated resin with the bricks  26  and mortar  28  of the manhole M not only stops water infiltration and gaseous and chemical deterioration in the manhole M, but also provides structural support thereafter. The resin  22  impregnating the ply  10  causes the ply  10  to be rigidified. The ply  10  is formed from a structural-type of fiberglass, so that it provides substantial support to the manhole M thereafter. The ply  14  is likewise formed from a structural fiberglass, and the resin system  22  impregnating the ply  14  likewise causes the ply  14  to become rigidified. The rigidified plies  10  and  14  thereby provide structural support to the manhole, substantially increasing its usable life. 
     Moreover, the mechanical attachment of outer fibers  12   b ,  12   c  to plies  10  and  14  provide further structural support and integrity to the rehabilitated manhole M. Ply  14 , when rigidified to fibers  12   b  of ply  12 , protects the inner membrane  12   a  of outer ply  12 , such as when the manhole M may be accessed for inspection, line cleaning, or televising of sewer lines within the system. It is not unusual to access manholes with ladders, harnesses and other devices and to use different types of equipment within the manhole structure. Such equipment could, however, tear the non-porous ply  12 , so as to permit water infiltration. Therefore, the bonding of the two structural layers of resin impregnated fiberglass to the outer fibers  12   b ,  12   c  is important for providing extra structural support for the non-porous inner membrane  12   a.    
     After curing of the resin system, the non-porous membrane  12   a  provides a permanent barrier to stop further deterioration of the manhole from gases or chemicals and eliminates any infiltration or exfiltration. The bladder  16 , when removed, uncovers the cut portion  20  which surrounds the laterals  40  and  42  so as to permit access to the them. While this invention has been primarily described for rehabilitating manholes, it may also be used in large diameter pipes and passages. 
     While this invention has been described as having a preferred design, it is understood it is capable of further modifications, uses and/or adaptations of the invention following the general principle of the invention and including such departures from the present disclosure which come within known or customary practice in the art to which the invention pertains, and as may be applied to the central features hereinbefore set forth, and falls in the scope of the invention and the limits of the appended claims.