Method for sealing joints in plastic lined pipes
AssigneeAmeron, Inc.
InventorBurl B. Ohnstad
Life of this patent
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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.
Claims3
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.
Dependencies are inferred from the claim text.