Pipe joints or couplings – Packed – Sleeve
Reexamination Certificate
1999-08-05
2001-08-21
Luu, Teri Pham (Department: 3627)
Pipe joints or couplings
Packed
Sleeve
C285S398000
Reexamination Certificate
active
06276727
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a pipe connector and in particular to a slip-on compression coupling for thermoplastic pipe. Thermoplastic pipe has become popular for many industrial and agricultural uses, particularly for installations where the pipe is frequently moved, or must be installed to convey abrasive or corrosive substances.
For example, in the mining industry, thermoplastic pipe is remarkably durable for transporting abrasive slurries in the processing of ores. When removing or depositing slurries, the piping must frequently be moved to optimize transport of this bulk material. Additionally, sections of the piping must occasionally be replaced, when the inner walls of the pipe began to wear thin. A pipe coupling that can be easily installed in the field to couple severed ends of thermoplastic pipe is advantageous. When this interconnection is accomplished with a mechanical coupling device, without chemical or thermal bonding, the task is simplified. Additionally, use of a mechanical coupling can permit the interconnection of pipe segments during rain or inclement weather where thermal coupling is not possible. It is therefore a principal object of this invention to provide a coupling device for thermoplastic pipe that interconnects pipe ends mechanically. The pipe coupling invented utilizes an internal compressive clamping force to interconnect an external coupler sleeve to the ends of thermoplastic pipe. The coupling can be used in irrigation or wastewater treatment projects, in chemical plants, processing industries or other conventional environments wherever thermoplastic pipe is used.
SUMMARY OF THE INVENTION
The slip-on compression coupling of this invention is designed for use with thermoplastic pipe. The compression coupling is designed to interconnect the ends of thermoplastic by a clamping force that causes a cold flow in the end segments of the interconnected pipe which seals the pipe and coupling and minimizes any interference with the rated flow capacity of the pipe.
The compression coupling of this invention slips over the butted ends of the thermoplastic pipe. A series of contoured compression shoes, each connected to an adjustment screw are positioned around the inside circumference of the pipe ends. The compression shoes span the end segments of the pipe. The butted pipe ends are spaced to permit the compression screws to be mounted through an outer sleeve of the coupling. External rotation of the screws results in adjustment of the shoes.
The compression shoes are contoured to the configuration of the flared end segments of the pipe after the end segments are flared upon tightening of the screws. Preferably, both the contact surface of the shoes and the inner contacting surface of the opposite cuff portion of the sleeve are grooved with a concentric saw tooth grooving. The series of groovings acts both as a labyrinth seal and a frictional grip for the thermoplastic pipe. The pipe deforms by cold flow to conform with the grooving, and the internal flaring of the sleeve on tightening of the adjustment screws. The end segments of the thermoplastic pipe are compressed between the compression shoes and the inner contacting surface. The cold flow displacement of the pipe against the internal flaring of the cuff portions of the sleeve allows positioning of the compression shoes after tightening, without reducing the effective inside diameter of the coupled conduit at the coupling.
The coupling of this invention is designed for thermoplastic pipe and other plastic-type pipe that has at least a limited elastic or cold flow deformability to effect sealing between the sleeve and pipe.
These and other features of this invention will become apparent from a consideration of detailed description of the preferred embodiment that follows.
REFERENCES:
patent: 2462721 (1949-02-01), Cohen
patent: 2814508 (1957-11-01), Seamark
patent: 3101208 (1963-08-01), Clifford et al.
patent: 4236736 (1980-12-01), Anderson
patent: 4865356 (1989-09-01), Moore et al.
Luu Teri Pham
Peterson Patent Attorney Richard Esty
LandOfFree
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