US4290836A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making composite pipe having an integral bell end
Assignee: Clow Corp
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Filing: 1980-04-07
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Granted: 1981-09-22
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Expires: 2000-04-07
Abstract
Abstract A composite reinforced plastic pipe having an integral bell end and method for making the same are disclosed wherein the composite pipe has a resin impregnated surfacing veil liner, a first resin impregnated continuous fiberglass strand reinforced layer coaxial along the inner liner, a sand-resin core layer formed along the cylindrical portion of the pipe but not on the bell end, a resin impregnated surfacing mat formed coaxially along the length of the exposed first fiberglass strand reinforced layer on the bell end and along the core layer, and an outer resin reinforced roving layer formed coaxially along the full length of the pipe, the composite pipe being cured to form a high strength pipe having uniform radial stiffness and improved resistance to water migration.
Inventors
- 👤 Alex L. McPherson
- 👤 Douglas E. Triestram
- 👤 James E. Lawrence, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 05:54
CPC Classifications
F; F16; F16L; F16L9/00; F16L9/12; F16L9/123; F16L17/00; F16L17/02; F16L17/03; F16L17/035; F16L47/00; F16L47/06; F16L47/08
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
299 words
A method of making a composite reinforced plastic pipe having a generally cylindrical tubular portion defining a spigot end and an opposite integral bell end adapted to receive the spigot end of a similarly configured pipe therein; said method comprising the steps of forming an annular inner liner or resin impregnated surfacing veil defining an axial passage having a first tubular portion of substantially uniform cylindrical cross section, forming an annular butting area circumferentially of said inner liner adjacent said bell end so as to define an annular surface for abutment with the spigot end of a mating pipe inserted into said bell end, forming an inner layer circumferentially of said inner liner by winding a resin impregnated continuous fiberglass roving helically on the outer surface of said inner liner and continuing said inner layer axially beyond one end of said inner liner and said butting area to form a second tubular portion defining said bell end, said inner layer defining an internal annular seal receiving groove in said bell end, forming a core layer of sand-resin composition circumferentially about and directly on the outer peripheral surface of said inner layer, said core layer being of substantially uniform cross section and formed along the length of said first tubular portion but terminating at said bell end so as not to form a part of said bell end, said sand-resin composition having a sand to resin weight ratio in the range of approximately 80:20 to 70:30, forming an outer layer of a plurality of lays of resin impregnated continuous fiberglass roving circumferentially about said core layer and the exposed surface of said inner layer so as to cooperate with said inner layer in defining said bell end, and curing the resulting composite pipe to effect bonding between the various layers.
Claim 2
Independent Claim
299 words
A method of making a composite reinforced plastic pipe having a generally cylindrical tubular portion defining a spigot end and an opposite integral bell end adapted to receive the spigot end of a similarly configured pipe therein; said method comprising the steps of forming an annular inner liner or resin impregnated surfacing veil defining an axial passage having a first tubular portion of substantially uniform cylindrical cross section, forming an annular butting area circumferentially of said inner liner adjacent said bell end so as to define an annular surface for abutment with the spigot end of a mating pipe inserted into said bell end, forming an inner layer circumferentially of said inner liner by winding a resin impregnated continuous fiberglass roving helically on the outer surface of said inner liner and continuing said inner layer axially beyond one end of said inner liner and said butting area to form a second tubular portion defining said bell end, said inner layer defining an internal annular seal receiving groove in said bell end, forming a core layer of sand-resin composition circumferentially about and directly on the outer peripheral surface of said inner layer, said core layer being of substantially uniform cross section and formed along the length of said first tubular portion but terminating at said bell end so as not to form a part of said bell end, said sand-resin composition having a sand to resin weight ratio in the range of approximately 80:20 to 70:30, forming an outer layer of a plurality of lays of resin impregnated continuous fiberglass roving circumferentially about said core layer and the exposed surface of said inner layer so as to cooperate with said inner layer in defining said bell end, and curing the resulting composite pipe to effect bonding between the various layers.
Claim 3
Dependent Claim
29 words
The method as defined in claim 1 wherein said bell end is formed with an annular internal radial recess adapted to receive and axially retain an annular seal therein.
Claim 4
Dependent Claim
41 words
The method as defined in claim 1 including the further step of forming a layer of randomly oriented, resin impregnated, surfacing veil over the outer exposed surfaces of said core layer and said inner layer prior to forming said outer layer.
Claim 5
Dependent Claim
25 words
The method of claim 3 wherein said layer of randomly oriented surfacing veil is applied as a 10 to 30 mil layer over the core.
Claim 6
Dependent Claim
26 words
The method of claim 3 including the step of applying a gel coat layer internally of the bell end of the composite pipe after curing thereof.
Claim 7
Dependent Claim
29 words
The method of claim 1 wherein said sand is substantially pure silica having a homogeneous average particle size diameter throughout said core layer of approximately 0.0112 inch (0.0285 cm.).
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-09-21 | 1985-03-23 | 1985-09-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-09-21 | 1989-03-23 | 1989-09-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-09-21 | 1993-03-23 | 1993-09-22 | $7700.00 | Window Closed / Lapsed |