Flange connection is a pipe connection method, specifically refers to the two ends of the line docking cast flange, in the flange end surface has a sealing groove, the groove containing sealing ring, docking with bolts or double-headed studs to closely connect the lines together.
Connection method with pipe
(1) Butt welding type (welding neck flange: symbol WN)
It is grooved and butt welded to the pipe.
It has a highly reliable structure with excellent strength against thermal stress and vibration.
It also has the advantage of being able to finish the inner surface smoothly. Suitable for high temperature and high pressure applications.
(2) Insert weldable (slip-on flange: symbol SO)
Insert the tube into the flange and weld the inside of the inner diameter of the outer part of the pipe on the back of the flange to two places.
Since there is no need for bealying, it can be easily installed, but it is not used for high-temperature piping because it is inferior in terms of welding strength and reliability.
(3) Socket weldable (socket weld flange: symbol SW)
The flange is provided with a body part, the tube is inserted, and one place outside the pipe on the back of the flange is welded to the sumi meat.
Unlike SO flanges, weld beads do not threaten the flange seal surface, but they are not used for high-pressure, high-temperature piping because reliability is reduced in one welding location.
(4) Screw-in type (Slade flange: symbol TR)
Tapered screws are applied to the flange inner diameter and tapered screws are applied to the pipe, and screwed and joined.
It eliminates the need for welding, but is unreliable in terms of sealing and is applied to fluid applications that are not hazardous at room temperature and constant pressure.
(5) Combination type (loose flange / wrap joint: symbol LJ)
A brimed pipe fitting called a “stub end” is joined and welded, and the tube is passed through the flange hole to place the brim of the stub end on the flange.
There are no constraints between the flange and the tube, so the flange bolt position can be freely adjusted.
In addition, flanges and tubes do not need to be welded, so they can be manufactured with different materials independent of weldability.
It is mainly applied to low-risk fluid applications at room temperature and constant pressure.