Static structures (e.g. – buildings) – With entrance for persons or objects in horizontal or... – Masonry or concrete
Reexamination Certificate
2000-03-15
2001-05-01
Chilcot, Richard (Department: 3635)
Static structures (e.g., buildings)
With entrance for persons or objects in horizontal or...
Masonry or concrete
Reexamination Certificate
active
06223475
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to an apparatus for producing liners for manholes, drainage pipes, sewer pipes and the like.
2. Description of the Prior Art
Liners for manholes and other drainage or sewer system are known in the art. Typically, a liner is applied to a deteriorating manhole in order to rehabilitate the manhole and return it to a safe and working condition. Application of such liner systems requires that the surfaces of the existing structure be thoroughly cleaned prior to application of the liner material to insure a strong bond between the material and the underlying structure. It is also common to seal the surface of the existing structure with a watertight sealant prior to application of the liner material to prevent water and other foreign substances from leaking between the liner and the structure, thereby causing the liner to disbond and fail.
One such liner system is described in U.S. Pat. No. 5,618,616 (Hume). There a multilayered liner system is provided for rehabilitating waste water system components. The existing, deteriorated structure is thoroughly cleaned to allow proper bonding of the liner material. A first primer layer is applied to seal the surface and then a plurality of additional foam and barrier layers are applied, as required. Each layer is sprayed applied. This method is time consuming, expensive and can be dangerous, as the personnel applying the liner may be exposed to harmful chemicals in a closed space with little or no air flow.
Systems have been developed whereby an entire manhole assembly may be constructed prior to installation. Such systems are useful for replacing deteriorated or non-functional manholes in existing waste water system or for providing a chemical and corrosion resistant manhole for use in new waste water system construction. Such a system is described in U.S. Pat. No. 5,303,518 (Strickland). A plastic liner having a provisions for creating mechanical lock with an outer shell of concrete is provided wherein the a plurality of projections extend outwardly from the liner into the concrete outer shell. The concrete flows around and between the projections thereby mechanically locking the liner to the concrete. The projections are integral to the liner and therefore, the liner material must be a material capable of being molded or shaped to form such projections, for instance, polyethylene or polyvinylchloride (PVC). In certain cases, additional processing may be required to provide a completed liner. Such processing may include cutting or milling the exterior surface of the liner to provide sufficient gaps or spaces for concrete to bond to the liner.
SUMMARY OF THE INVENTION
The present invention provides a method and apparatus for producing a liner system around which a manhole, drainage system, sewer system or the like can be installed to create a lined, interior surface having a concrete outer shell. In this way, the outer shell of the manhole is protected from the harsh internal environment encountered in most sewer and drainage systems, yet the manhole does not require retrofitting to provide a liner. In addition, the liner will mechanically bond to the outer shell of the manhole to prevent separation and subsequent failure of the liner and manhole.
The apparatus of the present invention produces a liner for use in constructing manholes, drainage systems, sewer systems and the like. The apparatus typically includes a rotatable mandrel having a moving slide collar, at least one sprayer for applying liner material to the mandrel and a rock dropper capable of covering the entire length of the mandrel. The mandrel should be constructed such that the completed liner can be easily removed therefrom without breaking, cutting or otherwise damaging the integrity of the liner. For instance, the mandrel may be provided with a non-stick or reduced friction surface allowing a completed liner to simply slide off the mandrel when complete. The mandrel may be pre-sized in order to provide an adequate liner diameter. Therefore, depending on the specific application the mandrel will have varying diameter. For manhole liners, a mandrel with a 4′ diameter is common. The mandrel will be rotatable such that an even coating of liner materials may be disposed on the surface thereof. Any suitable apparatus for rotating the mandrel may be used. In order to supply varying lengths of liner, the mandrel may be provided with a moveable slide collar which can be adjusted to produce a liner of a specified length.
The liner producing apparatus of the present invention also includes at least one sprayer capable of applying an even coating of liner material along the length of the mandrel. Depending on the specific application, multiple liner materials may be sprayed onto the mandrel, a plurality of sprayers may be used to avoid problems which may be caused by mixing materials in the sprayer or delays required to clean the sprayer after each material is applied. Multiple sprayers may also be used where the desired length of the liner is such that a single sprayer cannot adequately cover the entire mandrel. The sprayers may be automated. The liner material may also be applied to the mandrel manually, using hand-held, compressed air driven sprayers.
The rock dropper of the present invention is used to apply a uniform layer of rocks or other suitable particles to the mandrel after at least one coat of liner material has been applied. The rocks, once deposited on the mandrel, will be bound in place in the liner material. An additional layer of liner material may be applied to at least partially cover the rocks and form bonding loops, protrusions or bonding particles thereon. The loops being capable of forming a mechanical bond with the outer shell.
Although a liner may be produced as a single extended tube, typically, the liner is typically composed of a plurality of shorter tubes or sections which are joined to form the complete liner. The individual sections may have a flange at one or both ends capable of engaging adjacent sections such that the adjoined sections for a sufficiently tight seal to prevent leakage through the joint. A gasket may be included between each section to further aid in creating an adequate seal.
Once a liner is produced and properly sized, the liner is inserted into a larger mold. The liner is appropriately positioned within the mold and the outer shell material is then poured or injected into the mold to form the outer shell around the pre-formed liner. The loops on the liner surface extend into the outer shell material, forming a mechanical bond therewith.
In another embodiment, the liner may be used to repair existing waste water or sewage structures by providing a liner which may be inserted into the existing structure. Concrete may then be poured between the liner and the existing structure for secure the liner in place. This both strengthens the structure and provides protection against future exposure to harsh chemicals or other deteriorating or corrosive substances.
REFERENCES:
patent: 3938285 (1976-02-01), Gilbu
patent: 5106440 (1992-04-01), Tangeman
patent: 5303518 (1994-04-01), Strickland
patent: 5618616 (1997-04-01), Hume et al.
patent: 5725328 (1998-03-01), Schmager
patent: 6021815 (2000-02-01), Kiest, Jr. et al.
patent: 8-74280 (1996-03-01), None
Bracewell & Patterson L.L.P.
Chilcot Richard
LandOfFree
Method and apparatus for lining manholes does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for lining manholes, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for lining manholes will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2523322