A scrapper tee, also known as a flow tee or barred tee, is a type of pipe fitting that is used to ensure the safe passage of pipeline pigs across branch connections. A pig is a tool that is inserted into a pipeline to clean, inspect, or modify the pipeline. The scrapper tee has a series of bars or plates welded inside the branch outlet to prevent the pig from getting stuck.
Scrapper tee or sphere tee or flow tee essentially consists of concentric barred tees. The purpose of the scrapper tee is not to allow passage of the pig sphere/scrapper on the branch side.
The scrapper tee shall be suitable for pigging operation with process hydrocarbon/saw sea water. The scrapper tee inside diameter shall be same as that of inside diameter of riser in splash zone to maintain constant ID to permit smooth pigging operations.
No bar shall be used.
Maximum possible opening shall be provided through slots to limit the pressure drop i.e total opening shall be 1.0 to 1.5 times the branch pipe area.
Thickness of run/branch is to be calculated by vendor to the required design pressure and temperature and it shall match with the corresponding matching pipeline for free passage of pig as per DNV rules for submarine pipeline.
Scrapper tee / barred tee
Uses of scrapper tee
- Scrapper tees are used in pipelines to ensure the safe passage of pipeline pigs across branch connections. A pig is a tool that is inserted into a pipeline to clean, inspect, or modify the pipeline. The scrapper tee has a series of bars or plates welded inside the branch outlet to prevent the pig from getting stuck.
- The scrapper tee is used because it is a relatively simple and inexpensive way to prevent pigs from getting stuck. The bars or plates inside the branch outlet create a barrier that the pig cannot pass through. This helps to prevent the pig from getting damaged or causing damage to the pipeline.
- Scrapper tees are also used to prevent pigs from entering the wrong branch of a pipeline. This can be important in pipelines that have multiple branches, such as a trunk line with several laterals. The scrapper tee can help to ensure that the pig only enters the branch that it is intended to enter.
- Use to improve the efficiency of pig operations.
- Scrapper tees are an important safety feature in pipelines. They help to ensure that pigs can pass through pipelines safely and efficiently, without causing damage.
What are the factors to consider for choosing a scrapper tee
- size of the pipeline.
- type of pig that will be used.
- pressure and temperature of the fluid in the pipeline.
- material of the pipeline.
- environmental conditions.