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I<br />
7<br />
PIPELINE PIGS<br />
Pipelines require cleaning, and products require sepa-<br />
ration when being transported through the same line si-<br />
multaneously; pipeline pigs are used <strong>to</strong> make cleaning<br />
and separation possible.<br />
The slang word "pig" means scraper, ball, sphere, or<br />
other apparati used in pipelines. Figure 7-1 illustrates a<br />
Polly-Cast | pig made from polyester urethane. Pigs such<br />
as the Polly-Cast | can be used in gas, crude oil, salt wa-<br />
ter, refined product, and LPG lines. They are also avail-<br />
able with steel bristles on the wear surface, which in-<br />
creases the life of the urethane pig.<br />
Spherical balls or pigs (Figure 7-2) have been used for<br />
many years. They are available in solid material in sizes<br />
1 "through 12" and inflatable from 4" through 56". Pigs<br />
are inflated with a displacement pump capable of 250 psi<br />
or 1,724 kPa (Figure 7-3). This type of pig is often used in<br />
au<strong>to</strong>mated piping systems, meter proving, product sepa-<br />
ration, hydrostatic testing, and cleaning. Most are made<br />
from Neoprene, Nitrile, Polyurethane, or Vi<strong>to</strong>n.<br />
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