The principles and advantages/disadvantages of various connection methods for stainless steel pipes

Compression connection 

Connection principle: A radial compressive force (hydraulic clamp) is applied to securely fix the pipe fitting onto the pipe, and the water stop function of the O-ring is utilized to achieve the connection effect. 

Advantages and Disadvantages: 

1. Achieve thin-walled design for pipes and pipe fittings to save materials; 

2. Low connection strength (the connection strength of the interface is less than one-third of the strength of the pipe body); 

3. The pipeline is not detachable. 

4. If the burrs and flashings at the pipe ends are not thoroughly removed, they may damage the gaskets and become a potential cause of future leaks. 

Conical ring connection 

Connection principle: A radial compressive force (hydraulic clamp) is applied to securely fix the pipe fitting onto the pipe, and the water sealing effect is achieved through the sealing ring of the wide band rubber. 

Advantages and Disadvantages: 

1. Detachable; 

2. For pipe installation, add the process of rolling a convex ring at the pipe end. 

3. The cost of cast pipe fittings is relatively high. 

4. The interface strength is better than that of the compression type. 

Welding connection

Connection principle: Using the hot-melt process, the two connection components are fused together to achieve the connection effect. 

Advantages and Disadvantages: 

1. High connection strength; 

2. The gas protection of the weld seams at the on-site welding points fails to meet the standards, resulting in the weld seams being prone to rusting and directly reducing the service life of the pipeline. 

3. The installation quality is highly dependent on the skills of the welders and it is difficult to maintain consistency. 

Threaded connection with cone shape 

Connection principle: By directly tightening the pipe fittings or pipes, the two connection pieces with conical pipe threads on the inner and outer interfaces are tightened. Through the pressure seal provided by the connection interface threads (similar to the traditional threaded galvanized steel pipe seal), the connection effect is achieved. 

Advantages and Disadvantages: 

1. Detachable; 

2. The connection strength reaches the allowable strength of the pipe body. 

3. Easy to install, with stable and reliable quality; 

4. The thin-walled design of pipes and pipe fittings reduces manufacturing costs. 

5. When winding polytetrafluoroethylene tape around the external thread interface, apply a little force; if using liquid tape, the leakage rate of the interface can be zero. 

Ring compression connection 

Connection principle: A radial compressive force (hydraulic clamp) is applied to securely fix the pipe fitting onto the pipe, and the water sealing effect is achieved through the water-stop function of the wide-band rubber sealing ring. 

Advantages and Disadvantages: 

1. Achieve thin-walled design for pipes and pipe fittings to save materials; 

2. Due to the addition of an extra compression indentation, the connection strength is slightly better than that of the compression fitting type (the interface strength still does not reach half of the pipe body strength). 

3. The pipeline is not detachable; 

4. Since the indentation is circular in shape, the pipe can easily rotate, which adversely affects the sealing effect. 

5. If the burrs and flashings at the pipe ends are not thoroughly removed, they may damage the gaskets and become a potential cause of future leaks. 

Flange connection 

Connection principle: By tightening the bolts, two connection components with flange plates are connected, and the connection effect is achieved through the sealing of the flat sealing sheet. 

Advantages and Disadvantages: 

1. Detachable; 

2. High connection strength; 

3. Easy to install and with stable quality; 

4. The cost of the flange is too high. 

Groove connection 

Connection principle: By tightening the nuts of the pipe fittings, the pipe with a convex ring is axially pressed against the pipe fittings, and the water-blocking effect of the conical sealing ring is utilized to achieve the connection. 

Advantages and Disadvantages: 

1. Detachable; 

2. For pipe installation, add the process of rolling a concave ring at the pipe end. 

3. The cost of the cast clamps is very high. 

4. It cannot be used in pipes with negative pressure.