1. Gate Valves

                     
Advantages of Gate Valves

• Easy to install.
• Low pressure drop across the valve.
• Highly effective at shutting off flow; suitable for use with viscous fluids.
• Bi-directional flow capability (e.g., left-to-right or right-to-left); suitable for piping systems where the direction of fluid flow may change.
  

• Opening and closing takes a long time.
• Friction occurs between the gate and the valve seat surface during operation, which can cause scratches on the seat surface and impair the valve's sealing performance.
• Not suitable for fluids containing suspended solids or toxic substances.

2. Globe Valves

• Excellent flow rate regulation capabilities.
• Highly robust valve body structure.
• Suitable for high-pressure or high-temperature applications.
• Can be adapted for use as an automatic control valve (provided the valve plug is appropriately designed).

Precautions for Globe Valves

• They exhibit a high pressure drop across the valve.
• The valve seat is susceptible to damage from debris trapped between the valve disc and the seat during opening and closing operations.
• They are heavy, which may impact structural design.
• They are unsuitable for applications requiring high fluid purity or the absence of impurities, as residue tends to accumulate inside the valve body.
  

3. Check Valves

• Installed at the water pump outlet to prevent backflow into the pump when it stops operating.
• Low pressure drop across the valve.
• Can be installed in either horizontal or vertical positions (depending on the valve model).

• For swing-type valves, a loud noise may occur when the valve disc impacts the seat during closing, potentially causing damage to the seat.
• Leakage may occur if the fluid contains sediment or impurities.

4. Ball Valves

       
Advantages of ball valves

• Quick opening and closing; requires only a 90-degree turn of the valve stem.
• Suitable for applications requiring frequent operation.
• Low pressure drop across the valve.
• Capable of providing a tight, rapid shut-off of the fluid flow.
  

• Not suitable for extremely high-temperature applications.
• Use with fluids containing impurities may scratch or damage the seat and ball.
• Select the seat and ball materials to suit the operating temperature and pressure.

5. Butterfly Valves

• Quick and convenient to open and close; allows for flow rate adjustment.
• Simple structure; features a slim, lightweight design.
• Requires less installation space compared to other types of valves.
• Easy to install and maintain.

• Not suitable for precise flow rate control.
• Not suitable for high-pressure applications.
• The valve seat is in constant contact with the fluid, making it susceptible to wear; such wear can lead to leakage.
• Opening and closing the valve requires significant force, so a gear mechanism may be needed to provide mechanical advantage.