US3616288A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cement-lined metal pipe with improved bond between pipe and lining
Assignee: Mobil Oil AS
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Filing: 1969-06-26
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Granted: 1971-10-26
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Expires: 1989-06-26
Abstract
Abstract This specification discloses an improved cement-lined pipe and a method of roughening the interior surface of metal pipe in preparation for receiving a cement lining. The interior surface is roughened by depositing metal in the form of protrusions from an electrolytic solution by passing direct current therethrough. Cement lining may be applied to the interior surface of the pipe having protrusions formed thereon to produce a cement-lined pipe having increased bond strength between the cement and the pipe.
Inventors
- 👤 Earl S Snavely Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 05:43
CPC Classifications
F; F16; F16L; F16L58/00; F16L58/02; F16L58/04; F16L58/06; C; C25; C25D; C25D5/00; C25D5/60; C25D5/605; C25D5/627
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
100 words
A method of roughening the interior surface of metal pipe to be cement lined, comprising: putting into said pipe an electrolytic solution containing metal ions; inserting an electrode within said pipe; and imposing a DC voltage source between said electrode and said pipe with said electrode being connected to the positive terminal of said source and said pipe being connected to the negative terminal of said source wherein a sufficient direct current is passed through said solution for a sufficient time to form protrusions of a height of at least 0.002 inch on the interior surface of said metal pipe.
Claim 2
Dependent Claim
12 words
The method of claim 2 wherein said electrode is an elongated shaft.
Claim 3
Independent Claim
100 words
A method of lining metal pipe with cement, comprising: passing a direct electric current through an electrolytic solution of metal ions in contact with the interior surface of said pipe, said current being passed between the interior surface of said pipe and an electrode which is positive with respect to said interior surface for a time sufficient to form protrusions of a height of at least 0.002 inch on said interior surface; and forming a cement lining about the interior surface of said pipe whereby the bonding strength between said pipe and said cement is increased due to said protrusions.
Claim 4
Dependent Claim
30 words
The method of claim 4 wherein said electrolytic solution is selected from the class consisting of ferrous sulfate, ferrous acetate, ferrous ammonium sulfate, ferrous chloride, ferrous thiocyanate, and mixtures thereof.
Claim 5
Dependent Claim
22 words
The method of claim 4 wherein the DC voltage source has a potential within the range of 2 to 12 DC volts.
Claim 6
Dependent Claim
44 words
The method of claim 4 wherein said current has an amplitude within the range of 0.1 to 1.0 ampere per square inch and is passed through said electrolytic solution for a period of time within the range of 50 minutes to 5 minutes, respectively.
Claim 7
Independent Claim
118 words
A method of lining iron pipe with cement, comprising: filling said pipe with an electrolytic solution comprised of ferrous sulfate; inserting an electrode within said pipe; imposing a DC voltage source between said electrode and said pipe with said electrode being connected to the positive terminal of said source and said pipe being connected to the negative terminal of said source and passing a direct current of about 0.4 ampere per square inch through said solution for about 20 minutes to form protrusions on the interior surface of said pipe; and forming a cement lining about the interior surface of said pipe whereby the bonding strength between said pipe and said cement is increased due to said protrusions.
Claim 8
Dependent Claim
63 words
A conduit comprising a metal pipe, a cement lining disposed adjacent the interior surface of said pipe and in contact Therewith, and a plurality of electrolytically deposited protrusions of a height of at least 0.002 inch on the interior surface of said pipe extending into said cement lining to effect a bond between said cement lining and the interior surface of said pipe.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-10-25 | 1975-04-26 | 1975-10-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-10-25 | 1979-04-26 | 1979-10-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-10-25 | 1983-04-26 | 1983-10-26 | $7700.00 | Window Closed / Lapsed |