Pipe flanges are method of connecting pipes, valves, pumps and other equipment to form a piping system.
— Flanges by material & standars—
Except the most used standard flanges, there are still a number of special flanges such as:
Lap Joint FlangesFor pipes that are frequently taken apart for repair or replacement, lap joint flanges are used. These flanges are used with a universal stub-end insert that is easily rotated and makes it easy to line up bolt holes. This type of flange is used for junctures that do not come in contact with anything flowing through the pipes, which increases their durability and renders them reusable. Caution should be taken not to use lap joint flanges for jobs where high temperatures or high pressure conditions are possible.
The Slip-on flange has a low hub because the pipe slips into the flange prior to welding.
It is welded both inside and out to provide suffcient strength and prevent leakage.Slip-on flanges are all bored slightly larger than the O.D. of the pipe. They are preferred over welding neck flanges bu many users due to their lower intial cost, but final intallation cost is probably not much less than that of the welding neck flange because of the additional welding involved.
Threaded Flanges, TH FlangesThis popular type of flange not only comes in a wide range of materials and sizes, it can also be attached to pipes without welding, as it is a threaded flange. Extremely useful in connecting small pipes, it is a low cost flange that can be safely used in highly explosive and high pressure areas of projects and machinery.
Welding Neck Flanges, NW Long Weld Neck FlangesThe most popular type of high pressure pipe flange is the weld neck flange. The tapered hub design provides an extremely strong connection and these flanges can be repeatedly manipulated and bent without compromising the quality of the material and/or connection. The weld neck flange is highly resistant to extreme high and low temperatures.
Socket Welding Flanges, SW FlangeThe socket welding flange was created specifically for small piping that must withstand high pressure and/or contact with chemicals. With expert grinding and welding, socket welding flanges allow the unfettered flow of any type of liquid.
Standards, Dimensions & Weight
ASME/ANSI B16.5 Class 150 SW
ASME/ANSI B16.5 Class 300 SW
ASME/ANSI B16.5 Class 600 SW
ASME/ANSI B16.5 Class 1500 SW
These flanges are commonly used to seal or blank off the ends of valves and pipes. They are always round and have bolt holes around their perimeter. They are economical.
Cabon steel: A105, A350 LF2
Stainless steel: A182 F304/F304L/F316/F316L/F321
Alloy steel: F11, F12
Packing: plywood case and plywood pallet
Some piping system designs require constant changes in pipe diameters to accommodate changing conditions. The reducing flange economically connects different types and sizes of flanges, can endure extreme changes in pressure and are easy to attach.
Except for the bore and hub dimensions, the flange will have dimensions of the larger pipe size.