National standard pipe cap

The national standard tube hat is one of the various pressure vessel boiler and can seal accessories, to achieve the sealing effect. The use range of the general national standard cap is in: 19mm - 6000mm the larger size of the sealing head of the model will be more problematic. Let's take a look at the use of the cap.

1. The shape of the cap of the national standard: according to the requirements and reasonable of the equipment, choose the right type of header, such as oval, butterfly, conical and spherical;

2. Size of the national standard tube cap: refers to the inner diameter or outer diameter of the cap. If 377 and 426 are the external diameter; 350, 400 and 450 are based on internal diameter;

3, the national standard pipe cap height: the height of the general head we are all in accordance with the national standards for production, but there is not the same as the customer's product design, need to head height is different, so the order have special requirements on both sides to agree;

4, the national standard pipe cap material: the use of more general is 304 stainless steel and carbon steel, but also has a special purpose, such as high temperature resistant material must be in the 310 s, acid must be used 316 l material, etc.;

5, gb cap: the perimeter of the head is made of die stamping, there will be some stress in steel during forming a kind of existence, and there will be a relative deformation in the process of stamping tensile, so the diameter of the head to how to determine accurate or not, depends on the perimeter, whether standard;

6. National standard tube cap and barrel welding: when the sealing head and cylinder body are welded together, the sealing head and the tube shall be fixed on average with several points, and then the welding process shall be evenly distributed;

National standard pipe cap is the main pressure parts of boilers and pressure vessels, national standard pipe cap is the main pressure parts of boilers and pressure vessels to its structure and shape design is reasonable, affecting the peace of boiler, pressure vessel. So there are restrictions on the shape of various national standard caps.

No flanged spherical punching head: there are obvious shape mutations in the joint of the spherical sealing head and the cylinder body without folding. So it only applies to smaller, less stressed containers. A large additional bending stress can be generated when the spherical head is not folded. The inner radius of the national standard cap should not exceed the diameter of the tube.

Spherical seal head: the convex seal head of boiler and pressure vessel should be spherical head. The ratio of its length axis should not be greater than 2.5. The criterion ellipsoid (Dnhn = 4) is adopted for the non-standard ellipsoidal head.

Saucer head: disc seal head is a spherical head with folded edge. There are large bending stresses. Therefore, it is not ideal in engineering use. When the disc seal is used, the ellipsoidal head is mainly membrane stress. The radius should not be less than 10 percent of the diameter of the header, and not less than 3 times the thickness of the header. The inner radius of the header should not be larger than the inside diameter of the header.

The steel seal of carbon steel can crack in the environment of nitrate, ammonia, alkaline sodium, etc., please indicate the removal of residual stress at the time of order. The austenitic stainless steel will have a stress corrosion crack under certain conditions of chlorine ion. Please select the appropriate material at design time. For hot-dip galvanized or aluminized carbon steel containers, do heat treatment first to remove residual stresses.