A pin wheel pig is designed in a similar way to a standard mandrel bodied pig but it is fitted with heavy duty polyurethane discs fitted with pins into which tungsten carbide or ceramic balls are mounted which protrude from the edge of the disc.
Cast into the polyurethane disc are threaded ferrules into which the “pins” are screwed. The number of pins can be changed in order to give the required coverage dependent on how aggressive the cleaning action needs to be.
A studded pig has the studs mounted into the edge of the discs but unlike the pins these cannot be removed. Again they are used for the removal of scale and hard wax deposits and like the pin wheel unit, the studded unit is towed by a tractor pig with a universal joint connecting the two together.
iNPIPE PRODUCTS™ has developed the required technique for reinforcing the pinwheel discs to facilitate the mounting of the pins to prevent them tearing. A series of discs that are mounted on to the pig body with pins that are offset to give the required coverage until collectively they give a 360⁰ coverage of the pipe wall being cleaned. As previously mentioned, both the pinwheel module and the stud module are generally used as the towed module of an articulated pig. Because this type of pig is a very aggressive cleaning tool it is most important to ensure that a progressive cleaning programme is conducted to minimise the risk of a blockage. This allows for a number of runs to be conducted, each time increasing the number of pins, from 50% to 75% to 100%.
Experience has proved that careful consideration is required when using this type of cleaning tool as the design of the pig means that all debris is left in the line to be subsequently and systematically removed by a bulldozer pig that can be fitted with magnets to remove potential ferrous debris from the line.
Benefits of Pin-Wheel or Studded Pigs
- Studded discs and cups can be fitted to bi-directional pigs, cup pigs and foam pigs depending upon application
- Studded discs and cups can be fitted during conceptual design or provided as retro-fit components as required
- Studded disc and cup designs can accommodate multi-diameters as required
- Care must be taken during engineering to ensure that studs and retaining ferrules are correctly moulded into the material.
- Magnetic, acoustic, electro-magnetic and radioactive source tracking options are all available with Magnetic Pigs
- Depending upon application, the use of brushes should be considered in association with studs to maximise cleaning of ferrous debris and potentially reduce the number of cleaning runs required