I. Definition of malleable cast iron tees
Malleable cast iron tees are a type of pipe fitting used in piping systems, mainly used to branch fluids from one main pipe to two or more pipes. Due to the good mechanical properties and corrosion resistance of its material, malleable cast iron, tees are widely used in various industrial and civil piping systems.
II. Classification of malleable cast iron tees
1. Classification by structural form
- Straight Tee: The branch pipe is in the same plane as the main pipe, usually used for simple fluid diversion.
- Wye Tee: The branch pipe is not in the same plane as the main pipe, and the branch pipe has a certain inclination angle relative to the main pipe, which helps to improve the fluid flow characteristics.
- Equal Tee is a pipe connector whose diameters of all branch pipes are equal to the diameter of the main pipe. This design makes the flow characteristics of the fluid at the branch point more uniform, and is suitable for piping systems that need to maintain fluid flow consistency.
- Reducing Tee is a pipe connector with a main pipe and two branch pipes, where at least one branch pipe has a different diameter from the main pipe. This design allows the fluid to flow at different speeds and pressures in different branch pipes, and is suitable for occasions where different flow distributions are required.
2. Classification by connection method
- Welded Tee: Connected to the pipe by welding, suitable for high pressure and high temperature environments.
- Threaded Tee: Connected to the pipe by thread, suitable for low pressure and smaller diameter pipes.
- Flange Tee: Connected to the pipe by flange, suitable for occasions that require quick disassembly and maintenance.
3. Classification by material
Mallet cast iron tee: Made of malleable cast iron, it has good mechanical properties and corrosion resistance. Tees of other materials: Tees made of materials such as stainless steel and copper are suitable for specific chemical environments or higher corrosion resistance requirements.
III. The difference between malleable cast iron equal tees and reducing tees
Equal Tees and reducing tees in malleable cast iron pipe fittings have different functions of diversion or confluence in the pipeline system. The core difference lies in the pipe diameter design of the branch pipe. The following is a detailed comparison between the two:
1. Structural design: The pipe diameters of the three ports of the Equal Tees are exactly the same, and the diameters of the branch pipe and the main pipe are the same. The structure is symmetrical and suitable for scenarios where equal diversion or confluence is required in the pipeline system. Reducing Tee: The pipe diameter of the branch port is smaller than the main pipe diameter (for example, the main pipe DN50, the branch DN32), or there are multiple diameter reductions between different ports.
The structure is asymmetric and suitable for scenarios where flow or pressure distribution needs to be adjusted.
2. Application scenarios: Equal Tees are mainly used in situations where fluids need to be evenly distributed in the pipeline system, such as supplying water to multiple branches of the same diameter in the water supply network, symmetrical pipe layout in the fire protection system, and pressure-equalizing branches in the pneumatic system. Reducing tees are suitable for scenarios that require flow regulation or pressure control, such as the main pipeline diverting to a smaller branch (such as connecting a main water supply pipe to a small-diameter branch). It is necessary to reduce the branch flow rate (such as reducing branch impact in a chemical pipeline). Fluids of different pipe diameters are brought together in a confluence system (such as a sewage treatment pipeline).
3. Influence of fluid characteristics: For Equal Tees, the resistance of the fluid at the branch is relatively small, but uneven flow distribution may cause turbulence. Suitable for systems with high requirements for flow rate and pressure balance. For reducing tees, due to sudden changes in pipe diameter, the local resistance at the branch is large, which may cause turbulence or pressure loss. The branch flow rate can be adjusted by a variable diameter design (the flow rate of a small-diameter branch is lower), which is suitable for systems that require flow control.
4. Installation and maintenance: For Equal Tees, no additional adapter is required during installation, with high compatibility and simple maintenance. The symmetrical structure is evenly stressed and has good long-term stability. Reducing tees need to match pipes of different diameters and may need to be used with reducing joints. Due to the asymmetric structure, attention should be paid to the stress concentration problem on the branch side, and support should be added if necessary.
5. Standards and selection: Equal Tees have clear standard specifications (such as DN15-DN100) and are commonly used in general pipeline systems (GB/T 3287, ASTM A197). Reducing tees need to mark the specific dimensions of the main pipe and branch pipe (such as DN50×DN32), and the ratio of the reducing diameter needs to be selected according to the working conditions. Some non-standard specifications need to be customized.
6. Cost and process: Equal Tees have simple manufacturing processes, low costs, and strong inventory versatility. Reducing tees require special molds and complex processes due to the reducing structure, and the cost is usually higher than that of Equal Tees. Non-standard specifications may have a longer delivery cycle.
IV. Summary of selection suggestions
When the flow requirements of the branch and the main pipe are the same and the installation needs to be simplified (such as symmetrical water supply and gas supply systems), choose Equal Tees.
When it is necessary to adjust the branch flow, match pipes of different diameters, or optimize the system pressure by reducing the diameter (such as main line pressure reduction and diversion). Choose a reducing tee.
Notes:
1. The small-diameter end of the reducing tee branch may be eroded due to excessive flow rate (especially in fluids containing particles), so the wear resistance of the material needs to be evaluated.
2. In high-pressure systems, forging reducing tees are preferred to ensure strength.
3. If flexible flow adjustment is required, a combination of Equal Tees + independent valves can also be used, but the cost is higher.