Wax pigs are carefully designed to safely remove wax without risk of blockage
Propipe Limited has provided a number of pigs for the pre-inspection cleaning and everyday maintenance cleaning of pipelines that experience wax deposition. Pigs are designed specific to the conditions of each pipeline and can be tested by Propipe to confirm performance expectations
Wax adheres to the internal diameter of the pipeline once the temperature drops and as long as there is a temperature differential across the pipe wall. Wax is initially soft with a high liquid content but given time, this slowly hardens as the oil is stripped out of the wax composition.
Pigging is used to remove the wax mechanically from the pipe wall. If the pigging frequency is low the wax is allowed to harden, so the correct pigging frequency will prevent hard wax build-up.
The most effective pig type for de-waxing is the bi-directional type pig (or Bi-Di).
The pig consists of a metal body, with two flanges to bolt on the seal packages front and rear. Each seal pack consists of rigid guide discs (one or more) and flexible sealing discs (typically two or three). The guide discs support the weight of the pig and keep it central in the pipe but also provide an essential de-waxing / cleaning duty.
The shape of the guide disc means that it provides a cleaning action, where the flat front of the guide disc removes wax from the pipe wall.
For further information on this process including Wax Candle Formation please download our data sheet below.