ABOUT PURGING BY PIG

Removal Of In-Pipe Materials

In general there are several methods used for removal of deposits and obstructions from inside pipes. One method is the solvent method in which large quantities of solvents are used to remove obstructions. Another method is the gas method in which gases like air or N2 are force fed through pipes to clear them of deposits and obstructions.

However the more advanced pig method for decoking, removes scales and other contaminants with much greater speed and efficiency.

In addition by installing our exclusively designed, Launcher, Receiver, Quick closure, Pig pass-through Signaler, Detector and Ball-valve, we believe we can improve the performance of your system at all times.

  • Routine material change from time to time > Paint, dyestuff, foodstuff, etc. Everlasting change > Heavy-oil line and light-oil line
  • Paint, foodstuff (chocolate etc.) and other similar materials
  • Overhauling, cutting and welding of pipe lines
  • Investigation of in-pipe corrosion status
  • Crude oil and heavy oil

Regarding purging lines by pigs, we recommend that you select the type of application depending on chemical properties, viscosity, specific gravity, fluid temperature, and the shape of the piping arrangement.
However, at times, pigs can't be used. This is caused by excessively high (140 °C ) and low temperatures and chemical proofing.
In particular you should pay attention to the following chemicals: Methylene and Ethylene chloride picked up from ketone groups and ester groups that are picked up from halogenated hydrocarbons.

Cautions to be taken

  1. Piping arrangements with many T-s joints in general should be avoided.
  2. Pigs generally shouldn't be used in bends found in thread socket types and compression bends.
  3. Pigs should match the inside pipe diameter in ball valves.
  4. A pig entering prevention bar should be installed in branched sections.
  5. Two or more gas exhaust ports should be installed on the receiver.

Applicable Temperatures

Applicable temperatures range from 0 to 100°C. But we can manufacture a pig designed to stand temperatures from 100 to 150°C. Please contact us for details.

Removal of Remaining Contaminants by Pig Purging

In general contaminants ranging from 1 to 6 percent remain and are caused by the following:

  • ・Properties of liquid
  • ・The speed the pig advances at
  • ・Compression of the bent section
  • ・The port size in the piping line
  • ・Roughness of the pipe wall
  • ・How the piping materials are connected

In general, the remaining volume by pig purging is approx. 1 to 6%