Abstract: There is disclosed a method for coating an interior surface of an elongated pipe member. The method uses a first plug member having a resilient cylindrical body with an outer diameter close to an inner diameter of the pipe member, and a second plug member having a cylindrical body of an outer diameter smaller than the inner diameter of the pipe member and a brush provided at an end portion of the body of the second plug member, the brush having radially outwardly extending fibers having radial outer ends defining a cylindrical surface of which diameter is close to the diameter of the pipe member.

Abstract: A sweeper for sweeping the interior space of a pipe by passing the sweeper through the pipe to remove scale form the inner surface of the pipe. The sweeper includes a body made of a resilient material, such as foamed polyurethane, and a plurality of pins projecting radially outward from the body. Each of the pins includes a head portion located outward the body and stem portion for holding the pin on the body. The head portion of the pin includes a plurality of fingers having tip end surfaces which are inclined in opposite directions relative to the direction of movement of the sweeper in the pipe.

Abstract: A sweeper for sweeping the interior space of a pipe by passing the sweeper through the pipe to remove scale from the inner surface of the pipe. The sweeper includes a body made of a resilient material, such as foamed polyurethane, and a plurality of pins projecting radially outward from the body. Each of the pins includes a head portion located outward the body and stem portion for holding the pin on the body. The head portion of the pin includes a plurality of fingers having tip end surfaces which are inclined in opposite directions relative to the direction of movement of the sweeper in the pipe.

Abstract: A method of cleaning the interior of a pipe includes introducing a group of small spheres into the interior of the pipe, each small sphere having a number of pins driven therein in such a manner that respective heads of the pins are left exposed, applying hydraulic pressure to the group of small spheres from one side thereof, and causing the group of small spheres to flow through the interior of the pipe substantially along a hydromechanic velocity distribution curve. The small spheres form a mass within the pipe and undergo motion in accordance with a velocity distribution curve that conforms to the pipe diameter, thus making it possible to clean the interior of a pipe the diameter of which varies along its length.

Abstract: A pin for a sweeper used to scrape scale off the inner wall of a pipe has a shaft portion, an anchoring portion at the lower end of the shaft portion for being driven into the sweeper body to prevent the pin from falling out, and a head portion at the upper end of the shaft portion. The head portion has a plurality of spaced, generally pyramidal projections for contacting and scraping off scale. The projections are arranged in such a manner that the tip portions thereof do not overlap one another when the head portion is viewed from the side. The head portion may alternatively include a plurality of stacked plate-shaped bodies each of which has corner portions. The plate-shaped bodies are stacked on one another and are successively angular offset in the same direction in such a manner that equal angles are formed between corresponding corner portions of mutually adjacent ones of the plate-shaped bodies.