Valves are indispensable control components in fluid transmission systems. Their selection should be determined based on specific application scenarios, fluid properties, and operational requirements. Understanding the structures and functions of the five common types of valves - gate valves, globe valves, butterfly valves, ball valves, and check valves - is helpful for better system design and maintenance. 

Valves are indispensable control components in fluid transmission systems, with diverse structures and functions, suitable for various application scenarios. The following is an introduction to the structures and functions of five common types of valves: 

1. Gate valve 

The main structural component of a gate valve is the gate plate. The flow of fluid is controlled by the up and down movement of the gate plate. The advantages of a gate valve include low fluid resistance, easy operation and closing, suitability for bidirectional flow, and the sealing surface is less likely to be eroded when fully open. It is widely used in medium and low pressure as well as high pressure pipeline systems and is suitable for the use of large-diameter valves. 

2. Check Valve 

The structural feature of a stop valve is that the valve disc moves vertically along the center line of the valve seat, and the sealing surface is tightly attached by the pressure of the valve stem. Its advantages are low frictional force and strong durability, making it suitable for medium and low pressure as well as high pressure systems. However, the stop valve can only allow one-way flow and has a relatively high resistance to fluid. 

3. Butterfly Valve 

The valve disc of a butterfly valve is a circular plate that rotates around an axis within the valve seat. The flow rate of the fluid can be controlled by adjusting the position of the butterfly plate. The butterfly valve has a simple structure, small size, light weight, low operating torque, and quick opening and closing. It is widely used in hot water pipelines, chemical pipelines, and other scenarios where flow regulation is required. 

4. Ball Valve 

The core component of a ball valve is a spherical body with holes. The valve is opened and closed by rotating the ball. The advantages of a ball valve include low fluid resistance, excellent sealing performance, rapid opening and closing, and the ability to be equipped with various drive mechanisms for automated operation. It is suitable for applications where frequent opening and closing is required, such as in the petrochemical, chemical, and power industries. 

5. Check Valve 

A check valve is a type of valve that automatically opens and closes based on the force of the flowing fluid, and is mainly used to prevent the reverse flow of fluid. Depending on the structure, check valves are divided into lift type and swing type. The valve disc of the lift type check valve moves along the vertical center line of the valve body, while the valve disc of the swing type check valve rotates around the pin shaft outside the seat. Check valves are widely used in places where single-direction flow is required, such as the outlet of water pumps and the outlet of steam traps.