A 'pig' is some sort of plug that you send down a pipe to clean out what is currently in the pipe. Typically they are elastomeric materials and can come on a variety of shapes and sizes. Most commonly they are cyllindrical in shape.
What the pig does is you insert it into your piping system, the pressurize the pipe behind it with compressed gas. This forces the pig down the pipe forcing whatever fluid ahead of it out (remember to keep the other end of the pipe open). When it reaches the end of the pipe, all of the fluid has been forced out and you have a pipe that is essentially clean and now filled with whatever gas you used to 'pig' the line.
Their used is a bit complicated because you must incorporate launch and capture stations into your piping system, so there are some specialized things that must be done in your design to accomodate these.
They can also be purchased with RF transmitters in case they get stuck which is not an uncommon problem. When that happens you can then zero in on them from the transmitter and find where the pig has become lodged. Otherwise you will find yourself drilling holes in the pipe to see if there is either liquid or gas coming out to determine the location of the pig.
Other applications are in oil pipeline service where these devices are used to scrub the accumulated parrafins from the walls of the pipes rather than remove the liquid.
2. Batching Pig, This is where you want/need to use the single pipe line to transport different products. You insert a "Batching Pig" between the two products and keep pumping with out the need to enpty the line.
3. De-scaling Pig, This is where you use a more mechanical pig that has scrapers. This "Pig" removes unwanted build-up on the inside wall of the pipe which may be causing a reduction in flow.
4. Test Pig, This where the pig is fitted with any number and type of sensors and instruments to check the pipe line for defects such as bad welds, corrosion, etc.
5. Meter Prover Pig, This is where there is a flow meter on a pipe line that s used for the sale of products and the "sales Meter" needs to be tested and/or calibrated. Special pigs and prover stations (built-in or portable) are used.
Pigging system
Re: Pigging system
