Welded flange

Flat - welded flange is commonly referred to as plate, also called lap - welded flange.The connection between flat welded flanges and pipes is to insert the pipe into the inner hole of the flanges to the proper position before lap welding.

Product parameters

1. Flange outer diameter: 75mm-2190mm

2. Center circle diameter of bolt hole: 50mm-- 2130mm

3. Bolt hole diameter: 11mm-30mm

4. Number of bolt holes: 4-48

5. Thread: m10-m27

6. Flange thickness: 12mm-58mm

7. Pipe outside diameter: A(17.2-2032mm) B(14-20202020mm)

8.Flange inner diameter: A(18-2036mm) B(15-2024mm)

9. theoretical weight of flange: 0.36kg--234.6kg (DN1800)

10. Flange pressure: 0.25mpa-4.0mpa

Principles and characteristics

Of flat welding flange this problem has been more attention topic, it is related to the production cost of companies and enterprises, or economic benefit, so about the flat welding flange sealing principle is constantly improved and perfected.

However, the main design defect of flat welded flange is that it can not guarantee no leakage.This is insufficient on its design: the connection is dynamic, and such as thermal expansion and the ups and downs of cyclic load can create the flange surface between the moving, affect the function of the flange, to destroy the integrity of the flange is damaged, eventually lead to leakage.It is impossible for any product to be free from defects, but to minimize the defects of the product. Therefore, the company tries to improve the performance of the product and make it work when producing flat welded flanges.

Features of flat welded flanges: flat welded flanges not only save space and reduce weight, but also ensure the joint parts will not leak out, with good sealing performance.The compact flange size is reduced by reducing the diameter of the sealing element, which will reduce the section of the sealing surface.Second, the flange gasket has been replaced by a sealing ring to ensure that the seal is matched to the sealing surface.In this way, only minimal pressure is required to keep the cover tight.As the pressure required to reduce, the size of the bolt and the required quantity can be reduced accordingly, so the final design out a small volume and light weight (70% ~ 80% reduction in weight than traditional flange) of new products.Therefore, flat-welded flanges are a kind of high quality flanges, which reduce the quality and space, and play an important role in industrial use.

Sealing principle of flat welded flanges: two sealing faces of bolts squeeze flange gaskets together to form a seal, but this also leads to seal failure.In order to maintain the seal, you have to maintain a large force on the bolts, so the bolts have to be larger.Larger bolts would have to match larger nuts, which means that larger diameter bolts would be required to create conditions for tightening the nuts.However, the larger the diameter of the bolt, the applicable flange will become bent by increasing the wall thickness of the flange part.The entire device will require enormous size and weight, which is a particular problem in offshore environments, where weight is always a major concern.And, fundamentally, flat-welded flanges are an inefficient seal that requires 50 percent of the bolted load to be used to squeeze the gasket, while only 50 percent is used to maintain pressure.