US4054473A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for sealing joints in plastic lined pipes
Assignee: Ameron Inc
•
Filing: 1975-11-26
•
Granted: 1977-10-18
•
Expires: 1995-11-26
Abstract
Abstract The thermoplastic lining at a joint between adjacent lined pipe sections is sealed by means of a preformed elongated flat strip of thermoplastic material having resistance heater elements in spaced parallel relation along either side of the strip. The strip is placed circumferentially around the inside of the joint with the width of the strip bridging the joint and with the heater elements in contact with the respective liners on either side of the joint. Pressure is applied radially outwardly against the strip to urge the strip against the liners, and electric current is then passed through the heater elements to fuse the strip to the respective liners and seal off the joint.
Inventors
- 👤 Burl B. Ohnstad
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 20:44
CPC Classifications
B; B29; B29D; B29D23/00; B29D23/001; B29D23/003; B29D23/005; B29C; B29C65/00; B29C65/02; B29C65/34; B29C65/3404; B29C65/342; B29C66/00; B29C66/01; B29C66/05; B29C66/10; B29C66/11; B29C66/112; B29C66/1122; B29C66/50; B29C66/51; B29C66/52; B29C66/522; B29C66/5221; B29C66/61; B29C66/612; B29C66/70; B29C66/71; B29C66/80; B29C66/82; B29C66/824; B29C66/8242; B29C66/83; B29C66/832; B29C66/8322; F; F16; F16L; F16L47/00; F16L47/02; F16L47/03; F16L58/00; F16L58/18; F16L58/185; B29C65/3444; B29C65/3452; B29C65/3472; B29C65/3476; B29C66/834; B29C66/8341; B29C66/83411; B29C66/83413; B29K; B29K2025/00
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
133 words
A method of joining the thermoplastic lining at a joint between adjacent lined pipe sections comprising the steps of: forming an elongated flat strip of thermoplastic material, attaching a pair of elongated resistance heater elements in spaced parallel relation longitudinally along one surface of the strip, applying the strip around the inside of the joint with the width of the strip bridging the joint and with the heater elements in contact with the liners respectively on either side of the joint, applying pressure radially outwardly against the strip to urge the strip against the adjoining liners, forming a plurality of electrical connections to the respective heater elements at equally spaced intervals along the length of the strip, and applying a voltage between each pair of adjacent connections of each of the heater elements.
Claim 2
Independent Claim
133 words
A method of joining the thermoplastic lining at a joint between adjacent lined pipe sections comprising the steps of: forming an elongated flat strip of thermoplastic material, attaching a pair of elongated resistance heater elements in spaced parallel relation longitudinally along one surface of the strip, applying the strip around the inside of the joint with the width of the strip bridging the joint and with the heater elements in contact with the liners respectively on either side of the joint, applying pressure radially outwardly against the strip to urge the strip against the adjoining liners, forming a plurality of electrical connections to the respective heater elements at equally spaced intervals along the length of the strip, and applying a voltage between each pair of adjacent connections of each of the heater elements.
Claim 3
Dependent Claim
39 words
The method of claim 1 wherein the voltage is applied by electrically connecting alternate ones of said electrical connections to one terminal of a voltage source, and connecting the remaining connections to the other terminal of a voltage source.
Claim 4
Dependent Claim
62 words
The method of claim 1 further including the steps of forming the heater elements by wrapping resistance wire in a helix on an elongated filament of thermoplastic material, laying the filaments along the margin of the strip, heating the filaments by passing electric current through the resistance wire, and pressing the filaments against the strip to fuse the filaments to the strip.
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) | 1980-10-17 | 1981-04-18 | 1981-10-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-10-17 | 1985-04-18 | 1985-10-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-10-17 | 1989-04-18 | 1989-10-18 | $7700.00 | Window Closed / Lapsed |