Barred Tee / Pigged Tee
Piping Tees are used either for dividing main flow in two streams or for combining flow from two streams. Tees are normal or perpendicular to the pipe axis and normally produced by forging and are designed based on ASME B 16.9 or ASME B 16.11.
Barred tee is the special type of tee and is designed like adding bar plates inside the branch outlet on a normal tee. In pig launcher or receiver system, barred tee is used to ensure the pig could pass the branch safely.There is no international standard dimension for the barred tee. It is custom-made using the ASME B16.9/ MSS-SP 75 tee as a base with or without the help of Shell DEP 18.104.22.168-Gen or ISO 15590-2 standard.
The bar plates in sufficient quantity, thickness, and adequately spaced are welded internally at the branch to ensure the smoothness for the pig to run through the main pipe, and at the same time not affect the flow direction or getting stuck at the branch outlet. The bars are to be small enough not to restrict the flow but large enough to sustain the pressure of the flow. Sharp edges and burs are removed and the bars are to be grind to the branch curvature inorder to protect the pig sensors from damage. Bar plates are made with same material for weldability. Weld Repairs on Parent metal are prohibited. Standard practice is to avoid welding guide bars directly on the high-stress concentrated areas of the extrusion neck. Bar ends must be machined to fit the branch.
Universal Engineering Services has more than a decades experience in the pressure vessel design for clients in UAE, Oman, Qatar, Kuwait, Bahrain, Saudi Arabia, and many more countries all over the world. UES work to many ASME standards to design and validate pressure vessels, boiler, fittings and piping systems. We are also experts in Stress analysis of piping, structural design, ASME Joint review, Design of Storage tanks, code calculations, FEA/FEM, and spotless service on design management.
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