Size Standard of Casing Coupling

As the name implies, casing coupling is a kind of joint that connects casing pipe and pipe together. It is mainly used for the connection between casing pipe and pipe, which can effectively prevent water leakage, air leakage and other problems in pipe, and ensure the normal operation of pipe. Compared with the traditional welding connection method, the connection of casing coupling is tighter and more stable. It can also be disassembled and replaced according to actual needs, which is more convenient to use.

The size of casing coupling varies according to specifications. The common outer diameter ranges from 21.3mm to 114.3mm, and the inner diameter is determined according to the wall thickness of the matching pipe. The length is usually between 100mm and 300mm. The specific size needs to refer to national or industry standards, such as API 5CT.

Casing coupling size standard

Casing coupling size standards are divided into international standards and Chinese standards. The following are common standards and their main contents:

1. International standards

Common international standards include American standards, European standards and Japanese standards. Taking the US standard as an example, its main contents are as follows:

Nominal diameter range: 1/2 inch (DN15) to 120 inches (DN3000).

Wall thickness requirements: ANSI B16.9 and other standards.

Joint type: divided into pipe flange connection, threaded connection, welding connection, etc.

2. Chinese standard

Common Chinese standards include GB, JB, SH/T, SY/T and other standards. Taking GB as an example, its main contents are as follows:

Nominal diameter range: 15mm to 3600mm.

Wall thickness requirements: GB, SH/T and other standards.

Joint type: divided into flange connection, threaded connection, welding connection, etc.

Differences between different standards

Due to differences in the basis for formulation, scope of application and development history between different standards, there are differences between different standards. Mainly manifested in the following aspects:

1. Nominal diameter range

The nominal diameter range of Chinese standards is larger than that of international standards.

2. Wall thickness requirements

The requirements for wall thickness in Chinese standards are stricter than those in international standards.

3. Joint type

There are many joint types in the Chinese standard, while the international standard is mainly flange connection.

Common sizes

There are many sizes of casing couplings. According to the size, they can be divided into large-diameter casing couplings and small-diameter casing couplings. The common sizes are shown in the following table:

Precautions for selecting casing couplings

In addition to the above basic size parameters, the following points should be noted when selecting casing couplings

1. Make sure that the selected coupling matches the material of the connected casing pipe to avoid connection problems caused by material differences.

2. Check the surface quality of the coupling to ensure that it is smooth and burr-free to avoid affecting the sealing effect.

3. Refer to national or industry standards (such as API 5CT, etc.) for purchase to ensure that the selected product meets the relevant requirements.

Summary

For casing coupling size standards, the international standards mainly include ISO, API, ASME, JIS, GB, JB, HG and other standards. There are many sizes of casing couplings, and the appropriate size can be selected according to actual use needs.