Another solution is to reline the sewer pipes on site. Such methods typically utilize a resin coated liner which is inserted into the existing sewer pipe line and fitted against the interior of the sewer pipe. The liner is held against the interior of the pipe while the resin cures to form a new pipe lining within the existing pipe.

One example of such a method is shown in U. S. Patent No. 4,366, 012.

In this patent, a process utilizing an elongated bladder tube having an inner tubular liner comprised of felt is shown. Uncured resin is introduced into the bladder tube and is used to impregnate the felt inner liner. The bladder tube and the tubular liner are then inserted into the end of the sewer pipe to be repaired, and moved to the area of the sewer pipe needing repair. Upon reaching the area of the sewer pipe needing repair, the impregnated felt liner is inverted out of the bladder tube so that it is on the outside surface of the bladder tube and is pressed against the interior surface of the sewer pipe.

When the resin cures, a new pipe liner is provided at the area to be repaired.

In many cases connection of lateral pipes to main sewer lines for residential or other customers was frequently accomplished by forming a hole in the main line with a sledge or the like. The lateral pipe was then simply abutted against the hole, and then the excavation back filled to cover the juncture. Often, this juncture of the lateral with the main line would leak, and would not provide a tight sealed connection.

With the growing concern regarding the environmental impact of sewage leakage, such junctures are primary concern for repair, and can be repaired simultaneously with the lining of the lateral pipe by the method of the present invention.

SUMMARY OF THE INVENTION It is therefore a general object of the present invention to provide an improved method and apparatus for repairing the juncture of a main sewer line with a lateral pipe.

Another object is to provide a method and apparatus for repairing the juncture of a lateral with a main line which may be accomplished solely from the sewer main line.

Another object is to provide an improved seal at the juncture of the lateral pipe to the main sewer line.

Another object is to use a single piece T-shaped or Y-shaped liner at the junction between the main sewer line and the lateral pipe which provides a full circle seal around the interior of the main sewer line and around the interior of the lateral pipe.

These and other objects of the present invention will be apparent to those skilled in the art.

SUMMARY OF THE INVENTION The foregoing objects may be achieved by an apparatus for repairing the junction of a sewer main line and a lateral pipe made according to the present invention. The apparatus comprises a bladder assembly having an elongated main bladder tube and an elongated lateral bladder tube. The main bladder tube includes first and second opposite ends and a main bladder tube opening positioned therebetween. The lateral bladder tube has a first end connected to the main bladder tube opening and has a second end.

The apparatus also includes a liner assembly formed of resin absorbent material and having a main liner tube and a lateral liner tube. The main liner tube includes a first end, a second end and a main liner tube opening intermediate the first and second ends. The lateral liner tube has a first

lateral line tube end in communication with the main liner tube opening and is connected to the main liner tube and sealed around the main liner tube opening.

The lateral bladder tube and the lateral liner tube are positioned at least partially within the main bladder tube, with the main liner tube being outside of, and surrounding the main bladder tube and being connected to the lateral liner tube through the main bladder tube opening.

The lateral liner tube is invertible through the main bladder tube opening to an inverted position outside of the main bladder tube whereby the main liner tube is on the exterior of the main bladder tube and the lateral liner tube is on the exterior of the lateral bladder tube.

The present invention also contemplates a method for forming a lateral/bladder assembly comprising forming a bladder assembly having a main bladder tube and a lateral bladder tube. The main bladder tube includes first and second opposite ends and an intermediate opening therebetween.

The lateral bladder tube has a first end connected to the intermediate opening of the main bladder tube and has a second end.

The method includes the step of inserting the lateral bladder tube inside the main bladder tube through the intermediate opening. Next, a liner assembly is formed of resin absorbent material and includes a lateral liner tube having a first and second end and a liner sheet having a sheet opening there in surrounding and attaching the first end of the lateral liner tube. The second end of the lateral liner tube is inserted into the intermediate opening of the bladder tube and is positioned at least partially inside the main bladder tube with the first end of the lateral liner tube being adjacent the intermediate opening of the main bladder tube, and with the liner sheet outside of the main bladder tube. The liner sheet is then formed into a main liner tube wrapped around and surrounding the main bladder tube adjacent the intermediate opening of the main bladder tube.

An important feature of the present invention is the T-shaped or Y- shaped liner assembly. This liner assembly is constructed from a resin

absorbent material and comprises a main liner tube and a lateral liner tube formed into a T-shaped or Y-shaped configuration. The single piece liner assembly is impregnated with an uncured resinous material capable of curing and hardening. The liner assembly is then positioned within the sewer main line pipe in a position wherein the lateral liner tube extends within the lateral sewer pipe and the main liner tube is within the main line sewer pipe. The main liner tube and the lateral liner tube are then pressed radially outwardly against the interior surfaces of the main line sewer pipe and the lateral line sewer pipe respectively. The resin is permitted to cure and harden to form the liner assembly into a single piece whereby the main liner tube provides a full circle seal around the interior of the main sewer pipe on both sides of the damaged junction and the lateral liner tube provides a full circle seal around the interior of the lateral sewer pipe adjacent the damaged junction.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is an exploded perspective view showing the assembly of the bladder tube of the present invention; Figure 2 is a sectional view through the completed bladder tube shown in Figure 1; Figure 3 is a perspective view of a liner assembly being constructed for the liner/bladder assembly of the present invention; Figure 4 is a sectional view similar to Figure 2, but with the liner assembly installed in the bladder assembly, to form the liner/bladder assembly; Figure 5 is a pictorial view showing the introduction of uncured resin into the liner/bladder assembly; Figure 6 is an enlarged perspective view showing using a roller to facilitate impregnating the liner with the resin; Figure 7 is a pictorial view of the liner/bladder assembly being installed on a launcher; Figure 8 is a view similar to Figure 7, showing a further step in connecting the liner/bladder assembly to the launcher;

Figure 9 is a pictorial view of the launcher with the liner/bladder assembly connected thereto, supported on a work platform; Figure 10 is a view similar to Figure 9, showing a subsequent step in attaching the liner/bladder assembly to the launcher; Figure 11 is an enlarged perspective view of the launcher with the liner/bladder assembly attached thereto and ready for installation in a sewer line; Figure 12 is a sectional view through the liner/bladder assembly within a sewer line, showing the assembly position within a main line ready for expansion into a lateral pipe; Figure 13 is a sectional view similar to Figure 12, but with the liner/bladder assembly expanded to install the liner.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, in which similar or corresponding parts are identified with the same reference numeral, and more particularly to Figure 1, the T-shaped bladder assembly is designated generally at 12 and forms a part of the liner/bladder assembly 10 shown in Figure 4. While the bladder assembly 12 is shown to be T-shaped it may also be Y-shaped or otherwise shaped to accommodate the angle at which the main sewer pipe and lateral sewer pipe are disposed relative to one another. Bladder assembly 12 includes a flat sheet 14 of translucent urethane scrim material which is connected to a lateral bladder tube 16 also formed of translucent urethane scrim material. Lateral bladder tube 16 is an elongated member having first and second ends 16A and 16B respectively, with the first end 16A attached around an opening 18 located generally centrally in flat sheet 14. Preferably, lateral tube 16 is attached to sheet 14 by welding or the like to form an airtight seal at the juncture.

Flat sheet 14 is then formed into a tube and two longitudinal side edges 14A and 14B are welded together to form a main line bladder tube 20 (shown in broken lines in Figure 1). Thus, main line bladder tube 20 and lateral

bladder tube 16 form a T-shaped or Y-shaped bladder assembly 12 which is a single integral piece that is translucent.

Referring to Figure 2, the second end 16B of lateral bladder tube 16 is inverted and drawn through the main line bladder tube 20 and out a first end 20A of the main line bladder tube 20, such that the first end 16A of the lateral bladder 16 is inverted to form an opening 22 in the side wall of main line bladder tube 20.

Referring now to Figure 3, the liner assembly utilized in the liner/bladder assembly 10 shown in Figure 4 is designated generally at 24.

Liner assembly 24 includes a tubular lateral liner 26 connected to a flat sheet liner 28. Both liners 26 and 28 are formed of felt or other resin absorbent material. Lateral liner 26 is formed by connected side edges of a sheet of liner material with a polymer coating on one side, such that the polymer coating 30 is on the exterior of the tube being formed. The edges of the sheet are sewn together at a seam 32, and a strip of polymer tape 34 is welded over the seam to form an airtight seal.

Flat sheet liner 28 has a central opening formed therein, and has a polymer coating 36 on the top surface thereof. The lateral liner tube 26 is sewn to the flat sheet liner 28 around the opening, and a strip of polymer tape 38 is then welded continuously around the juncture to form an airtight seal.

Once liner assembly 24 has been completed, the second end 26B of the lateral liner 26 is inserted into the opening 22 in the side of main line bladder 20 and drawn into the lateral bladder 16 until the liner flat sheet 28 contacts the main line bladder 20. This step may be accomplished by attaching a rope (not shown) to end 26B of the lateral liner 26, and threading the rope through lateral bladder tube 16. Pulling the rope then causes the lateral liner 26 to move to the position shown in Figure 4.

The second end 16B of the lateral bladder is closed off by inserting plug 15 which is held in place by a clamp 17. Extending through plug 15 are a PVC air pipe 21 and wick 40, as shown in Figures 4 and 5. Vacuum opening 19 is provided in the end 16B of bladder tube 16.

A quantity of curable resin 42 in liquid form is then introduced into the opening 44 of flat sheet liner 28 so as to continue into the lateral liner 26 within lateral bladder 16 (shown in Figure 5). A vacuum source (not shown) is connected over the vacuum opening 19 to collapse the walls of the lateral bladder 16 and lateral liner 26 as shown in Figure 6. The wick 40 will provide a path for evacuating gas from the lateral bladder 16 until the curable resin moves to the down stream end 16B of lateral liner 16 and completely impregnates the liner. Because the bladder assembly 12 is formed of a translucent material, it is possible to visually verify that the lateral liner 26 is completely impregnated with resin while inside the lateral bladder 16. A roller 46 is preferably utilized to move the slug of resin and assist in impregnating the liner 26 with the resin material.

Referring now to Figures 7 and 8, the liner/bladder assembly 10 is loaded into a launcher 48 for installation into a sewer pipe. Launcher 48 includes a hollow cylindrical tube 50 having forward and rearward ends 50A and 50B respectively. An aperture 52 is formed generally through the side wall of the launcher tube 50. The left hand edge of aperture 52 is provided with an upwardly extending flange 70 which facilitates the sliding of lateral bladder tube 16 into the launcher tube 50. The right side of the aperture 52 is provided with a downwardly curved wall 72 (Figure 12).

Launcher 50 includes a clevis 80 mounted adjacent its rear end.

Surrounding the rear end 50B of launcher 50 is a ring bearing 82, and mounted to ring bearing 82 are a pair of wheels 84 located at the 5 o'clock and 7 o'clock positions when viewed from an end view (not shown). The ring bearing 82 permits the wheels 84 to remain stationary while the entire body of the launcher 50 can be rotated about its longitudinal axis. Protruding outwardly from the surface of launcher tube 50 adjacent the rear end 50B are a pair of clamping ribs 86. Similarly a clamping rib 86 is provided adjacent the forward end 50A. A circular ring bearing 88 is also provided adjacent the forward end 50a and includes a pair of wheels 90 mounted thereon.

Liner/bladder assembly 10 is installed on the launcher 48 by inserting the second end 16B of lateral bladder 16 through aperture 52 and through launcher tube 50 and out the forward end 50A of the launcher tube 50. As the main line bladder tube 20 approaches the launcher 48, the rearward end 50B of the launcher tube 50 is inserted into the first end 20A of the main line bladder tube 20, as shown in Figure 8. The flat sheet liner 28 is moved over the launcher side wall aperture 52, with the main line bladder 20 extending on opposite sides of aperture 58.

As shown in Figures 9-11, the ends 20A, 20B of the main line bladder tube 20 are attached to the forward and rearward ends 50A and 50B of launcher tube 50 by bands 54, and the launcher tube is connected to a support frame 56 which holds the launcher 48 in the air. A collapsible hose 68 is clamped to the forward end 50a of launcher tube 50 by means of a clamp 92.

A two piece platform 58 is pivoted up into position to support the flat sheet liner 28 above the launcher 48. As shown in Figure 10, the two piece platform 58 includes two halves 58A and 58B with semicircular holes 60A and 60B which will form an aperture through which the lateral lining will extend when the platform is moved to the support position shown in Figure 9.

Uncured resin 42 is then poured onto the flat sheet liner 28 and worked into the liner material. The two piece platform 58 is then separated and lowered, as shown in Figure 10, and the flat sheet liner 28 is wrapped around the main line bladder 20, with one side edge 28A overlapping the other side edge 28B, as shown in Figure 11. Side edges 28A and 28B are temporarily held tightly together with straps 60 of hook and loop fastener, tape, rubber bands, or other similar fasteners.

A positioning robot 62 is then attached to the rearward end 50b of launcher tube 50, as shown in Figure 12 and is used to introduce the launcher 48 and liner/bladder assembly 10 into the sewer main line 64. Wheels 84,90 facilitate movement of assembly 10 within the main sewer line 64. The lateral liner opening 44 is aligned with the lateral pipe 66 to be repaired.

Bearings 82,88 permit the robot 62 to rotate assembly 10 a full 360° so as to

obtain alignment. Robot 62 also is capable of extending or retracting to move assembly 10 up to six inches for final exact alignment.

Once positioned, air pressure is applied within the launcher tube 50 via a"lay flat"tube 68 connected to the forward end 50a of launcher tube 50, to inflate the lateral bladder 16 and invert the lateral bladder upwardly into lateral pipe 66. The air pressure also presses the main liner 20 radially outwardly against main sewer line 64 and presses lateral liner 26 radially outwardly against lateral pipe 66 until the resin impregnated in the lateral liner 26 and main line liner 28 cures. Once cured, the generally T-shaped or Y-shaped liner assembly 24 is a one piece liner connecting the main pipe 64 with the lateral pipe 66 to seal them together. It provides full circle sealing of both the lateral pipe 66 and the main pipe 64. Because of the use of the polymer coated liner assembly 24, the actual liner assembly can be tested prior to installation in the ground, to ensure an airtight connection.

Whereas the invention has been shown and described in connection with the preferred embodiment thereof, many modifications, substitutions and additions may be made which are within the intended broad scope of the appended claims.