Degradable plug device for a pipe

A method of operating a degradable plug device for a pipe, wherein the steps of the method comprise:

• providing the degradable plug device within the pipe, wherein the degradable plug device comprises an outer plug body and an inner plug for preventing fluid flow through the pipe until the degradable plug device has been removed from the pipe or until the inner plug has been removed from the outer plug body, wherein the outer plug body and the inner plug are made of a degradable material, and wherein exposed surfaces of the degradable plug device comprise a protective layer thereon;
• disposing the inner plug in at least a first position, wherein the inner plug is in sealing contact with the outer plug body so as to define a chamber, and wherein one or both of the inner plug and the outer plug body prevents said fluid flow through the pipe;
• performing a degradation initiation operation such that fluid is able to enter the chamber to initiate corrosion or dissolution of at least the inner plug from inside the chamber, wherein performing said degradation initiation operation comprises moving the inner plug relative to the outer plug body between the first position and a second position, in which fluid is able to enter the chamber to initiate corrosion or dissolution of the inner plug from inside the chamber.

A degradable plug device for a pipe having an outer plug body and an inner plug for preventing fluid flow through the pipe until the degradable plug device has been removed from the pipe or until the inner plug has been removed from the outer plug body, wherein the outer plug body and the inner plug are made of a degradable material, wherein exposed surfaces of the degradable plug device comprise a protective layer thereon, wherein the inner plug is disposable in at least a first position, in which the inner plug is in sealing contact with the outer plug body so as to define a chamber, wherein a surface of the inner plug facing the chamber is uncoated with the protective layer, and wherein the inner plug is adapted to undergo, in use, a degradation initiation operation such that fluid is able to enter the chamber to initiate corrosion or dissolution of one or both of the inner plug and the outer plug body from inside the chamber.