FIELD OF THE DISCLOSURE

The disclosure relates generally to pipeline pigs. More particularly, the invention relates to wear indicators for pipeline pigs and pigging components having a pipe wall contacting surface that is subject to wear during pigging, such as but not limited to urethane components

BACKGROUND OF THE DISCLOSURE

A device that is transmitted through a pipeline is typically referred to as a pipeline pig. A pipeline pig may be used to clean the interior surface of the pipeline. Another use for a pipeline pig is for separating one fluid medium from another. Sometimes pipeline pigs are used for pushing out entrapped liquids in a gas transmitting pipeline. Pipeline pigs may be sent through a pipeline to gain information about the condition of the pipeline. Such pigs are frequently referred to as “instrumentation pigs” and these type of devices can be used to provide information as to the ovality of the pipeline, the interior diameter of various sections of the pipeline, the occurrence of dents, buckles or bulges in the pipeline wall, the detections of bends or changes in direction of the pipeline and the occurrence of corrosion in the pipeline interior or exterior walls.

Pipeline pigs include components that are in contact with the pipe wall and, therefore, subject to wear during use. By way of a non-liming example, pipeline pigs, particularly of the instrumentation type, normally employ elements such as cups or disks formed of a resilient material like urethane. The cups or disks serve two functions: (1) they support the body of the pig within the interior of the pipeline and (2) at least one element for each pig provides a piston-like action so that the flow of the fluid medium, whether liquid or gas, through the pipeline serves to propel the pig forward under differential pressure. The cups and disks have a limited service life and must be replaced when they become worn. However, monitoring wear relies upon guidelines of how to measure and determine the amount of wear as percent urethane remaining. In a number of cases, no monitoring is done. Instead, a “successful” run is considered an indication the cups and disks are functioning properly.

By way of example, some operators continue to use pigging devices long past the point where the pig is effective for its intended purpose such as cleaning. Cleaning pigs can quickly reach a point at which the pigging device no longer contacts or integrates with the pipeline wall and the pig is simply moving through the pipeline without pressure pushing it forward. The pig is basically along for the ride with the velocity of the stream within which it is immersed. The pig ending its ride in a pig receiver does not mean the pig performed its intended function when in the pipeline. Therefore, a need exists to quickly and easily determine the amount of wear experienced by pipe contracting surfaces and whether the amount of wear falls within a predetermined effective operating range.

SUMMARY

Embodiments of a pigging device of this disclosure include at least one pipe wall contacting surface and a wear indicator (gauge) arranged or configured to visually indicate an amount of material loss of the pipe wall contacting surface between a first size and a predetermined minimum effective size. The first size may be a predetermined maximum size indicative of when the pigging device is new or unused. The pipe wall contacting surface may be any shape suitable, including but not limited to spherical-shaped, cylindrical-shaped, cup-shaped, disc-shaped, conical-shaped, frusto-conical shaped, bowl-shaped, and bullet-shaped. In some embodiments, the pigging device is a pipeline pig such as but not limited to a spherical foam pig, a cylindrical-shaped foam pig, or a bullet-shaped foam pig. In other embodiments, the pigging device is a component of a pipeline pig such as but not limited to a cup or disc arranged about a body of the pipeline pig. The pigging device may also be a pigging disc element. The pigging device may be made of any suitable material, including but not limited to an elastomer such as urethane.

The wear indicator may be located on the pipe wall contacting surface or spaced from the contacting surface. The wear indicator may include one or more of the following: a raised surface such as but not limited to a ring or a bead; multiple raised or stepped surfaces; an insert having ends with different areas located toward and away from the pipe wall contacting surface; one or more similar-sized or different-sized cavities, holes, slots, or grooves; or a color or a material the same as or different than that of the pipe wall contacting surface. Examples of indicators include but are not limited to raised or grooved surfaces, inserted geometrics that will change dimensionally as a function of wear, drilling of holes into the device that will disappear or appear as the pipe wall contacting surface wears, grooved surfaces, and the use of layered colors of material.

Regardless of function, shape, or material of the pigging device, or the type of wear indicator used or its location relative to the pipe wall contacting surface, the pipe wall contacting surface has a first size “S1” at time “t1”, a second smaller size “S2” at time “t2”, and a predetermined effective minimum size “S3,” where t2>t1and S1>S2≥S3. The wear indicator is functional between S1and S3, with at least a portion of the wear indicator visible between S1and S3. In embodiments, the first size S1can be a predetermined maximum size indicative of when the pigging device is new or unused. The wear indicator is visible at S1to provide a visual control that helps to ensure that a replacement pigging device is new and not previously used. In some embodiments, a size S4may be indicated, where S3>S4. The size S3may also be the size at time “t3”, t3>t2, with S4being the predetermined effective minimum size. There may be intermediate wear indicators and sizes between S1and S3(or S4).

Embodiments of a method of this disclosure for indicating wear of a pipe wall contacting surface of a pigging device may include inserting the pigging device into one end of a pipeline; retrieving the pigging device at another end of the pipeline; and inspecting the wear indicator. No measurement device or physical measurement of the pigging device is required. Rather, the wear indicator immediately gives a user the information needed through visual inspection. at a glance and without a measurement device. The pigging device may be a pipeline pig or may be a component of the pig that is in contact with the pipe wall.

