What is long weld neck flange?

What is long weld neck flange?

Long weld neck flange(LWN flange) is also call integral flange, it means a welding neck flange has a very long neck. Commonly, the welding neck flange has a tapered neck and a bevel end which is going to butt welding with the matching pipe. But the long weld neck flange, has a straight short pipe as the neck of a long weld neck flange.

 

Uses:

LWN flanges are largely used in the petroleum and chemical industries but can also be used in residential and commercial buildings where fluctuating temperatures and high stress are expected, such as a main water or gas source. Long neck steel flanges are used under conditions where line or pipe expansion creates bending or repeated changes in the pipe. Because a long neck flange is used in pressurized applications, the flange may have additional pressure connections and may be referred to as an orifice flange. The flange supports free product flow when bored to match the diameter of the pipe it will receive. Long weld neck flanges are attached using V-shaped welds known as butt welds.

 

Standards:

 

Manufacturers of steel flanges follow specific production standards when designing or machining a flange. Dimensional tolerances and dimensions for long neck orifice flanges are covered in the American Society of Mechanical Engineers section 36 of publication B16. AMSE publication B.16 covers pipes and fittings made of steel, cast iron, cast bronze and wrought copper.

 

Dimensions of Long Weld Neck Flange:

 

The long weld neck flange should be butt welded with the pipes, it means the neck dimensions is same with the matching pipe, same diameter and wall thickness , commonly the long weld has a plain end, not a bevel end for welding . Except the neck, the LWN flange has a same dimensions with the welding neck flange. In addition, there are also the type LWN Heavy Barrel (HB) and the Equal LWN Barrel (E); they have a different shape and a thicker “Wall” which name is Nozzle .

 

Sealing Face of the Long Weld Neck Flange:

 

The sealing face of the long weld neck flange is same with the weld neck flange, so it could be raised face(RF), flat face(FF) or Ring Type Joint(RTJ) , the long weld neck flange is suitable to be used for the high pressure application. 

 

The long weld neck flange could be in many materials, carbon steel ,alloy steel or stainless steel .Hebei haihao group can supply the long weld neck flange as per customers’ requirements.

The NW Long Weld Neck Flange is normally referred to as the high hub flange. It is designed to transfer stresses to the pipe, thereby reducing high stress concentrations at the base of the flange. The NW Long Weld Neck Flange is the best designed butt-welded flange of those currently available becuase of its inherent structural value. It is expensive because of the design.

NW Long Weld Neck Flange

Tube OD sizes: 3/8 to 2 inches

Materials:
Flange: 304 or 316L stainless steel
O-rings: Viton, Buna, & silicone
Fasteners: Wingnut, SureSeal, bulkhead & EVAC clamps

Vacuum range
Elastomer seal: >=1 x 10^-8 Torr - High vacuum
EVAC metal seal: >=1 x 10^-11 Torr - UHV

Temperature range
Viton: -20°C to 200°C
Silicone: -50°C to 230°C
Buna: -30°C to 110°C
EVAC metal seal: -270°C to 150°C

Product name: long weld neck flange

Size  ½" (15 NB) to 36" (900NB) Class   150 LBS, 300 LBS, 600 LBS, 900 LBS, 1500 LBS, 2500 LBS Material Grade   Stainless Steel   ASTM A 182, A 240 F 304, 304L, 304H, 316, 316L, 316Ti, 310, 310S, 321, 321H, 317, 347, 347H,904L   Duplex Steel    ASTM / ASME A/SA 182 F 44, F 45, F51, F 53, F 55, F 60, F 61   Alloy Steel  ASTM / ASME A/SA 182 & A 387 F1, F5, F9, F11, F12, F22, F91   Carbon Steel   ASTM / ASME A/SA 105 ASTM / ASME A 350 , ASTM A 181 LF 2 / A516 Gr.70 A36, A694 F42, F46, F52, F60, F65, F70 In Form SORF, WNRF, BLRF, SWRF, LAP Joint, Threaded, Reducing, Spectacle, etc Specialize As per drawing  Value Added Services » CNC Machining  » Customized Flanges Standard » ANSI : ANSI B16.5, ANSI B16.47, MSS SP44, ANSI B16.36, ANSI B16.48 » DIN :  DIN2527, DIN2566, DIN2573, DIN2576, DIN2641, DIN2642, DIN2655, DIN2656, DIN2627, DIN2628, DIN2629, DIN 2631, DIN2632, DIN2633, DIN2634, DIN2635, DIN2636, DIN2637, DIN2638, DIN2673 » B.S : BS4504 , BS4504, BS1560, BS10

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