Definition and Structure

A four-way fitting is a pipe fitting with four ports that can connect one main pipe to three branch pipes, allowing fluid to flow in four directions. Its shape resembles a "+" sign, hence it is also called a cross pipe. The main part of the four-way fitting consists of a main pipe section and three branch pipe sections, and the diameters of the four ports can be designed to be the same or different according to actual needs.

Classification

Equal Diameter Four-Way: The four ports of an equal diameter four-way fitting have the same diameter. This type of four-way fitting is mainly used in situations where fluid needs to be evenly distributed from the main pipe to three branch pipes of the same diameter. For example, in some symmetrical pipeline layouts, equal diameter four-ways can evenly split the fluid from the main pipeline into three branch pipelines, commonly found in water supply and drainage systems, air conditioning, and ventilation systems that require uniform flow distribution.

Unequal Diameter Four-Way: The diameters of the main pipe and branch pipes in an unequal diameter four-way fitting are not completely the same and can be designed according to specific flow requirements and pipeline layouts. Unequal diameter four-ways can meet the connection and flow distribution needs between different diameters in a pipeline system. For instance, when connecting a main water supply pipeline to branch pipelines of different diameters, using an unequal diameter four-way can achieve a reasonable transition of diameters and effective flow distribution, widely used in various industrial pipeline systems and building water supply and drainage systems.

Material

Carbon Steel: Carbon steel four-way fittings have good strength and toughness, can withstand certain pressures and temperatures, and are relatively low in cost, suitable for general industrial pipeline systems and building water supply and drainage systems where corrosion resistance is not highly required.

Stainless Steel: Stainless steel four-way fittings have excellent corrosion resistance and can resist the erosion of corrosive media such as acids, alkalis, and salts. Therefore, they are widely used in industries such as chemical, food, and pharmaceuticals, where high corrosion resistance of pipeline materials is required, ensuring the long-term stable operation of pipeline systems in harsh corrosive environments.

Alloy Steel: Alloy steel four-way fittings have higher strength and high-temperature resistance, suitable for high-temperature and high-pressure pipeline systems, such as those in the petrochemical and power industries, meeting the usage requirements under extreme conditions.

Manufacturing Process

Casting: Casting four-way fittings involve pouring liquid metal into a pre-designed mold and cooling it under certain temperature and pressure conditions to solidify into shape. The casting process can produce complex shapes and larger four-way fittings, but the internal structure of castings may have some defects, such as pores and shrinkage cavities, which need to be ensured through subsequent processing and inspection to guarantee product quality.

Forging: Forged four-way fittings are formed by applying pressure to the blank material, causing it to undergo plastic deformation to achieve the desired shape. The forging process can make the internal structure of the metal material denser, improving the strength and toughness of the four-way fitting. However, forging equipment requires a larger investment, and production costs are relatively high, suitable for situations with high quality and performance requirements for four-way fittings.

Welding: Welded four-way fittings are formed by connecting pre-cut pipe fittings or steel plates together through welding processes. This manufacturing process can be flexibly combined according to different pipe diameters and shape requirements to produce various specifications of four-way fittings. The quality of welded four-way fittings mainly depends on the welding process and the choice of welding materials, as well as the skill level of the welders, requiring strict control of welding quality to ensure the sealing and strength of the four-way fitting.

Connection Methods

Welded Connection: Welding is one of the common connection methods for four-way fittings. By welding the ports of the four-way fitting to the pipeline, an integrated pipeline system is formed. Welded connections have the advantages of good sealing and high strength, capable of withstanding higher pressures and temperatures. However, welding operations require specialized equipment and technicians, and maintenance and repair can be relatively inconvenient.

Flanged Connection: A flanged connection involves installing a flange plate at the ports of the four-way fitting and then connecting the flange to the flange on the pipeline with bolts. Flanged connections are convenient for disassembly and maintenance, suitable for situations where frequent maintenance and replacement of fittings are required. However, flanged connections are relatively costly and occupy a larger area.

Threaded Connection: A threaded connection involves machining the ports of the four-way fitting into threads and then connecting them to pipes with corresponding threads. Threaded connections are easy and quick to install, but the sealing is relatively poor, generally suitable for low-pressure, small-diameter pipeline systems.

Application Scenarios

Water Supply and Drainage Systems: In the water supply and drainage pipelines within buildings, four-way fittings are commonly used to connect the main water supply or drainage pipes to multiple branch pipelines, achieving multi-directional distribution or collection of water. For example, in the water supply systems of large buildings, equal diameter four-way fittings can evenly distribute water from the main supply pipe to branch pipes on different floors or areas; unequal diameter four-way fittings can achieve reasonable diameter transitions and flow distribution according to the needs of branch pipes with different diameters.

Industrial Pipeline Systems: In industrial fields such as petroleum, chemical, and power, four-way fittings are used in various media transport pipeline systems. For instance, in petroleum and chemical production, four-way fittings can distribute crude oil, natural gas, and other media from the main pipeline to different processing equipment or branch pipelines, achieving complex process flows. In the steam pipeline systems of the power industry, four-way fittings can split steam from the main steam pipeline to multiple steam-using devices or branch pipelines, meeting different steam usage needs.

HVAC Systems: In HVAC systems, four-way fittings are used to connect supply air ducts, return air ducts, air conditioning equipment, and different branch air ducts. Equal diameter four-way fittings can evenly distribute air from the main duct to multiple branch ducts, ensuring uniform distribution of indoor air; unequal diameter four-way fittings can connect air ducts of different diameters according to the air conditioning load requirements of different rooms or areas, achieving reasonable air flow distribution and improving the operational efficiency of the air conditioning system.