RANGE OF PIGS | FDA POLYURETHANE | FDA SILICONE | DETECTABLE FDA SILICONE | ||
Size (nominal) |
Flexible Vane
|
Flexible Vane
|
Sphere
|
Flexible Vane
|
Sphere
|
1"/25mm | ♦ | ♦ | |||
1½"/38mm | ♦ | ||||
2"/50mm | ♦ | ♦ | ♦ | ♦ | ♦ |
2½"/62mm | ♦ | ♦ | ♦ | ♦ | ♦ |
3"/75mm | ♦ | ♦ | ♦ | ♦ | ♦ |
4"/100mm | ♦ | ♦ | ♦ | ||
5"/125mm | ♦ | ||||
6"/155mm | ♦ | ||||
6"/164mm | ♦ |
Does pig need replacing?
Just as vehicle tyres there are wear limits for the effective working diameter of a pig. Martec have applications where the pig can traverse 50km of pipe (typically 6 to 24 months) before this limit is reached but the numbers of bends and material in the pipe (friction) can dramatically affect this. The tell-tale signs indicating approach of a wear limit are dilution of product by process water, periodic pauses in the pig's progress or increased air pressure needed to maintain pig momentum.
At the extreme if on removal from the pipework the vanes do not return to their natural shape then the pig certainly needs replacing. Ensure the correct material is used as continual exposure to high operating or CIP temperatures will deform and/or stiffen the wiping vanes making them ineffective.
If the pig has suffered any mechanical damage clearly it should be replaced (it would be worthwhile isolating and correcting any recurring cause of mechanical damage).
If in any doubt we can advise. At Martec we are always happy to receive photos as these are often the most effective way to explain in-situ concerns.