Fluid Controls offers a range of flanges manufactured by it's sister concern Hyd-Air Engineering Works, Goa.
The use of weld nipple and ferrule type of fittings is widespread for tube sizes upto 38mm OD. For bigger sizes, ferrule and weld nipple type of fittings are impracticable because of their heavy hexagonal sections which increase the pitch between pipes and because of the high torques required for tightening them.
Flanges with Butt Weld or Socket Weld ends offer a practical solution to these shortcomings, leading to compact piping installations.
CETOP FLANGES:
CETOP PR 63H, AFNOR 48-0-54 and ISO 6164 specify flanges with Butt Weld ends and square clamping flanges for 250 bar and 400 bar static working pressures. These correspond to 160 bar and 315 bar dynamic working pressures respectively. The flange system consists of one or two sleeves to be butt or socket welded to the pipe and clamped together between two square flanges by a set of four hex bolts, nuts and spring washers. One of the sleeves carries an "O" ring groove fitted with an "O" ring for sealing the interface.
SAE FLANGES:
The use of these ISO 6164 flanges has one disadvantage. The size of the square flange requires a higher pitch between pipes due to the flange size. In order to reduce the distance between pipes, SAE introduced their own standards, which are now incorporated into ISO 6162 for 3000 psi and 6000 psi static pressure ranges. The SAE system depends on the same set of butt welding sleeves, held together by a set consisting of a split flange and a solid flange, secured by hex bolts and nuts.
The design for SAE flanges calls for forged flanges to ASTM A105 with sleeves made from weldable material. In order to reduce costs, various manufacturers have introduced a two piece system where the sleeve and the flange are combined into one piece. Such a system is easily adaptable to both the Butt Weld and Socket Weld systems.
Material
With the introduction of more corrosive fluids in piping systems, the total joint is not required to be of non-corrosive material (such as SS). Only the sleeves, which are wetted by the fluid, are required to be of SS. This makes for an economical joint.
Further, the orientation of these flange joints can be done in such a way so as minimize the distance between the pipes and provide for a compact installation.
