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US 7,069,772 B2Granted
Method to predict the end-point, replacement time and to monitor changes in that time by using pre aged witness coupons
OwnerDavid E. Kranbuehlinventor
Life of this patent
Estimating the term…
Abstract
A method involving the use and creation of pre-aged witness coupons which characterizes and monitors the rate and extent of chemical and physical aging of the polymer in the structure during use in the field is described.
Claims22
A method for assessing the life expectancy of a polymer lined pipe which transports fluids, comprising the steps of:
- positioning pre-aged polymer witness coupons in said polymer lined pipe, each of said pre-aged polymer witness coupons being made of the same material as a polymer in said polymer lined pipe, and each having a molecular weight, which can be the same or different for each pre-aged polymer witness coupon, which is less than an initial value for said polymer in said polymer lined pipe and more than a threshold replacement value for said polymer in said polymer lined pipe;
- determining an equilibrium molecular weight for said polymer based on changes in the molecular weight of said pre-aged polymer witness coupons over time;
- and
- comparing the equilibrium molecular weight to said threshold replacement value, and, based on the comparison determining whether
- (i) said polymer lined pipe will need to be replaced, or
- (ii) when said polymer lined pipe will need to be replaced.
3 more elements
A method of monitoring and controlling degradation of a polymer lined pipe which transports fluids, comprising the steps of:
- positioning pre-aged polymer witness coupons in said polymer lined pipe, each of said pre-aged polymer witness coupons being made of the same material as a polymer in said polymer lined pipe, and each having a molecular weight, which can be the same or different for each pre-aged polymer witness coupon, which is less than an initial value for said polymer in said polymer lined pipe and more than a threshold replacement value for said polymer in said polymer lined pipe;
- determining a rate of degradation of said polymer based on a rate of change in molecular weight of said pre-aged polymer witness coupons over time;
- and
- adjusting a pumping rate and/or composition of said fluids in said polymer lined pipe based on said rate of degradation determined in said determining step.
1 more element
A method for monitoring degradation of a polymer material, comprising the steps of:
- positioning pre-aged polymer witness coupons in a same environment in which a component comprising said polymer is used, each of said pre-aged polymer witness coupons being made of the same material as a polymer in said component, and each having a molecular weight, which can be the same or different for each pre-aged polymer witness coupon, which is less than an initial value for said polymer in said component and more than a threshold replacement value for said polymer in said component;
- determining an equilibrium molecular weight for said polymer based on changes in the molecular weight of said pre-aged polymer witness coupons over time;
- and
- comparing the equilibrium molecular weight to said threshold replacement value, and, based on the comparison determining an amount of degradation of said polymer.
1 more element
An array of polymer witness coupons for assessing the life expectancy of a polymer lined pipe which transports fluids, comprising:
- at least two pre-aged polymer witness coupons, each of said pre-aged polymer witness coupons being made of the same material as a polymer in said polymer lined pipe, and each having a molecular weight, which can be the same or different for each pre-aged polymer witness coupons, which is less than an initial value for said polymer in said polymer lined pipe and more than a threshold replacement value for said polymer in said polymer lined pipe;
- and
- means for positioning said at least two polymer witness coupons in said polymer lined pipe such that the at least two polymer witness coupons are exposed to the same environment conditions of said polymer in said polymer lined pipe.
A system for assessing the life expectancy of a polymer lined pipe which transports fluids, comprising:
- an array of pre-aged polymer witness coupons, each of said pre-aged polymer witness coupons being made of the same material as a polymer in said polymer lined pipe, and each having a molecular weight, which can be the same or different for each pre-aged polymer witness coupon, which is less than an initial value for said polymer in said polymer lined pipe and more than a threshold replacement value for said polymer in said polymer lined pipe, and each of said pre-aged polymer witness coupons being positionable in and retrievable from a position where said pre-aged polymer witness coupons are exposed to the same environmental conditions of said polymer in said polymer lined pipe;
- means for determining an equilibrium molecular weight for said polymer based on changes in the molecular weight of said pre-aged polymer witness coupons over time;
- and
- means for comparing the equilibrium molecular weight to said threshold replacement value, and, based on the comparison determining whether
- (i) said polymer lined pipe will need to be replaced, or
- (ii) when said polymer lined pipe will need to be replaced.
3 more elements
Dependencies are inferred from the claim text.