Pipe rehabilitation test mandrel

Details Pipe rehabilitation test mandrel Pipe rehabilitation test mandrel

1997-01-08

2001-01-23

Bagnell, David (Department: 3673)

Hydraulic and earth engineering

Subterranean or submarine pipe or cable laying, retrieving,...

C015S104050, C015S104310, C138S097000

Reexamination Certificate

active

06176644

ABSTRACT:

BACKGROUND OF THE INVENTION
Underground service pipes such as sewers which make up the utility infrastructure need replacement or rehabilitation as they age. Through normal service the lines, typically made of concrete, deteriorate or break allowing waste to escape. The buried pipes present access problems. Also, it is desirable to maintain sewer service while the replacement or rehabilitation of the sewer line takes place.
Repairing a service line can involve digging up most or all of the line and replacing the pipe. This is costly, labor intensive and disrupts normal service. Alternative methods such as pipe bursting have been developed which includes breaking up the old pipe underground and following the bursting operation with placement of new pipe in the space provided. Another alternative method involved extracting the old pipe at intervals and replacing it with new pipe by forcing the new pipe into the space provided after the extraction process. The old pipe that was extracted needed to be disposed of adding another economic factor to the method. Some of these methods utilized pipe jacking machines with hydraulic rams or mechanical drivers to push the new pipe in place. In some cases the pipe jacking equipment took up space in the excavation next to the pipe to be burst or extracted. The access thorough existing manholes was insufficient to accommodate the pipe jacking equipment.
The renewal or rehabilitation of the service lines without digging up the line was developed by inserting new pipe or slip lining with materials such as plastic pipe liners inside the old pipe. Rehabilitation of old pipe with a new internal slip lining requires cleaning the existing host pipe of debris that has built up with use. Some methods utilize stationary derricks for the cleaning operations with a drag bucket. The derricks need to be reset after each operation. The bucket size may be limited by the height of the derrick used to hoist the bucket to the surface. The pipe liner is pushed into the host pipe. Often the pressure exerted in the pushing operation is not evenly distributed causing damage to the liners.
The host pipe should be tested after the cleaning process to determine if debris has been removed and the pipe liner can fit. The new joints of liner pipe is then placed in the host pipe. The liner generally has a slightly smaller diameter than the inside of the host pipe.
SUMMARY OF THE INVENTION
This invention is a system for rehabilitating pipe such as sewer lines which renews the existing service lines without disrupting the flow through the lines. In this description the pipe may be described as a sewer line that is in need of rehabilitation. The system retains the host pipe and therefore the value of the structure in place while not creating additional waste disposal concerns with the extracted pipe. The system utilizes mobile equipment such as conventional excavators that are fitted with winches on the attachment points for custom tools, the winch manipulates and lifts the buckets for the cleaning operation, and the test mandrel and the pipe liner in the slip lining renewal operation.
The system for cleaning the sewer line is often needed prior to the slip lining process because of the debris built up in the sewer line after years of use or rapid deposition of debris because of adverse environment conditions. The present invention utilizes equipment that can be used for both the cleaning and relining process as well as testing the host pipe prior to relining to confirm that the interior of the host pipe is clear and the liner pipe will be received without damage.
In the rehabilitating system of the invention the length of host pipe is accessed on both ends. Manholes already present can be used as access on at least one end of the host pipe and are generally large enough for one end of the operation. A larger excavation to accept the new pipe liner and a test mandrel is required on the other end of the host pipe from the manhole.
In an embodiment of the system the host pipe is accessed through a shaft that can be an existing manhole. A down hole boom is inserted into the shaft. The down hole boom has a winch mounted and a guide roller mounted thereon. The guide roller is adjustably mounted so that when the down hole boom is placed in the shaft the guide roller is positioned to guide the cable from the winch over the roller into the host pipe. The down hole boom generally extends above the surface of the shaft. The winch is preferably mounted on the part of the boom above the surface. In one embodiment the winch on the down hole boom is also mounted to a mobile vehicle such as an excavator.
A selected length from the access shaft another access area to the host pipe is provided that is large enough to accommodate other equipment necessary for the rehabilitation process such as lengths of the new pipe liner. A host vehicle with a movable boom such as an excavator is positioned at the surface of the second access area. Various embodiments of the system use conventional excavators which are easily transported from site to site. A second winch is mounted on the end of the boom. The boom operator can manipulate the boom and winch so that the winch can be moved from above the surface into the access area and to the mouth of the host pipe. In the preferred embodiment, a housing is mounted to the end of the boom and surrounds the winch. The housing protects the winch, but allows for free movement of the cable spooled on the winch. The winch housing is attached to the boom on the custom attachment points used for other types of tools. The cables from both winches are capable of disengageable attachment to equipment used to rehabilitate the host pipe.
One of the pieces of equipment used to rehabilitate the host pipe which is part of the system is a cleaning bucket. The semicircular cleaning bucket is sized to be received in the host pipe. The cleaning bucket has a leading edge with a flap door that is generally semicircular and hinged to the top of one end of the bucket. The flap door swings to the inside of the bucket from the closed to open position. An open end is opposite to the flap door on the cleaning bucket. The cleaning bucket has points of attachment for to the cables such as yokes.
An additional piece of equipment of the system is a test mandrel used to determine if there are any obstructions in the host pipe prior to lining. The test mandrel is a cylindrical member with beveled edges on both ends. A plurality of internal ribs and internal pulling yokes are disposed inside the cylindrical member.
Another feature of the system is a pulling mandrel designed to distribute the pulling forces in an even manner around the pipe liner while it is pulled by the cable on a winch and pulled inside the host pipe. The mandrel also provides for areas of flow therethrough so the sewer remains in service during the slip lining operation. The pulling mandrel is a circular member with a diameter sized to be received into the host pipe and to contact the circumference of a liner for the host pipe. A plurality of spokes extend from the circular member and converge to the middle of the circular member to a central hub. The hub has an opening of sufficient size to accompany a cable passing therethrough.
The invention also includes methods for using the system in rehabilitating the sewer lines. The cleaning method starts with the selected length of host pipe described above that has at least two access points with one access that can be a manhole. The cleaning bucket described above is attached to a cable. In an embodiment one cable is strung between the two winches with the cleaning bucket attached. In a preferred embodiment of the system the cable from the winch on the down hole boom attached to a yoke on the leading edge of the cleaning bucket and the cable on the movable boom is attached to the open end of the cleaning bucket.
The cleaning bucket is lowered into the access area serviced by the winch on the movable mount. The cleaning bucket is pulled by spooling the winch on the down hole boo

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