Restoration, processing and cleaning of used pipes

A distinctive feature of any used pipe from a new one is the mandatory restoration and restoration work. Such work includes cleaning the outer and inner surfaces, grinding, dismantling of fasteners, welding and welding, applying new chamfers. Processing can be either partial (affects only some areas) or complete (the entire body of the rolled product is restored). All these processes are divided into cheap and more expensive, and their application is dictated by what result you want to get at the end. Let's look at them in more detail.

Before carrying out cleaning work, the product is freed from fasteners, welds and welds for further convenience of working with it.

Cleaning the outer surface of the pipe.

This process is divided into two stages: primary (rough) and final (fine) cleaning. It should be understood that fine cleaning cannot be carried out without primary. Primary (coarse) is divided into:

• manual;
• burning;
• machine;
• hydro-sandblasting.

Manual primary is the removal of polymer or rubber-bitumen insulation. This procedure is carried out by workers manually using scrapers, sharpened blades, knives and other improvised means. At low temperatures, the removal of bituminous insulation can be carried out with a sledgehammer, as bitumen becomes brittle in the cold. It is not difficult to guess that such methods are time-consuming and time-consuming, and do not provide complete disposal of old insulating materials.

Benefits:

• low cost (no need for special machines and units);
• you can reuse or sell downed bitumen;
• The process can take place almost anywhere.

Weaknesses:

• takes a long time;
• low quality;
• remains of insulating materials on the wall.

Manual cleaning may well be enough if the pipe is of poor quality and, as a result, will be used as piles, a case or a cover.

Incineration is the second most effective method. It consists in the complete removal of any insulation by burning it.

Benefits:

• does not require large investments, except for the purchase of firewood or other fuel for firing;
• fast in time;
• suitable for pipes coated with paint, primer, prime, etc.;
• leaves virtually no insulation residue on the surface.

Weaknesses:

• requires special permissions;

• highly polluting;
• at high temperatures there is a risk of rolled product deformation;
• Sandblasting is required after firing.

Primary cleaning on a lathe is more expensive than incineration, as it requires a special lathe. The process is as follows: the product is placed on rotating shafts. A scraper is pressed hydraulically or mechanically against its surface. When the pipe rotates on the shafts, the scraper moves along it, removing the insulation. Most often, this method is applied to pipes in bituminous insulation.

Benefits:

• high quality;
• high performance;
• you can reuse or sell the removed bitumen;

Weaknesses:

• requires a crane or overhead crane to remove/install the product on the machine;
• the ability to clean only straight pipes;

Hydrosandblasting (killing) is the most expensive, but the most effective method. It is carried out by a special unit that supplies a stream of water under high pressure to special nozzles. Allows you to get rid of almost any insulation.

Benefits:

• high speed and quality.

Weaknesses:

• high equipment price;
• high water consumption;
• the need for a good drainage system with a high drain rate.

Final (fine) cleaning is carried out using abrasives. Abrasives are called materials with high hardness and used for processing various surfaces. Such processing is divided into:

• shot blasting - cold processing of a product using iron shot;
• sandblasting - sand acts as an abrasive;
• sandblasting using thermal blowing - heated sand acts as an abrasive;
• hydrosandblasting - a sand-liquid mixture acts as an abrasive.

Cleaning the inner surface of the pipe

As well as external cleaning, internal cleaning is divided into coarse and fine. The rough methods are