Globe valve is a common flow control valve, widely used in liquid and gas pipeline systems. Its main function is to control the flow of fluid by adjusting the opening of the valve. The following is the valve body structure and working principle of the ball valve:
1. Valve body structure
The basic structure of a ball valve includes:
Valve body: the outer shell, usually made of metal.
Valve seat: the part that contacts the valve disc, and its sealing performance is very important.
Valve disc: connected to the operating mechanism by the valve stem, which can be moved to adjust the flow rate.
Valve stem: the valve disc is driven to move by a handwheel or electric device.
Valve cover: the upper part of the valve body, usually with a sealing device.
2. Working principle
El shutoff globe valves adjusts the fluid flow rate by the lifting or rotating movement of the valve disc. Its working principle is mainly based on the following key points:
(1) Closed state:
When the ball valve is closed, the valve disc is in close contact with the valve seat and the fluid cannot pass through. This is because the valve disc of the ball valve is usually spherical, and its surface is completely consistent with the valve seat, thus forming a good seal.
(2) Open state:
When the ball valve needs to be opened, the valve stem is rotated by an external drive device (such as a handwheel, electric drive or pneumatic device) to drive the valve disc to move. The valve disc is usually connected vertically to the valve seat. When the disc is completely removed from the valve seat, the fluid can flow freely through the ball valve.
(3) Flow adjustment:
By rotating the handwheel or electric device, the disc can be partially raised or lowered to adjust the opening area of the valve seat. The lifting position of the disc changes in proportion to the flow rate. As the disc rises, the opening area increases and the flow rate increases; when the disc is lowered, the opening area decreases and the flow rate decreases.
(4) Fluid flow direction:
When the fluid flows through the ball valve, it usually passes through the center hole of the valve seat. The movement of the disc directly affects the flow area of the fluid, thereby controlling the flow rate. The disc of the ball valve can have multiple through holes or multiple channels. Different disc designs can be selected according to needs to optimize fluid flow.
3. Valve adjustment
Opening and closing speed: The ball valve has a faster opening and closing speed and is suitable for applications that require fast opening or closing.
Adjustment accuracy: Although the ball valve can adjust the flow rate, its adjustment accuracy is low and it is usually not used in applications that require precise flow control. More common precision flow control uses a regulating valve (Globe Valve).
4. Control method
The control methods of ball valves include manual, electric, pneumatic, etc. The specific control methods are as follows:
Manual: Use a handwheel to rotate the valve stem to drive the valve disc to rise and fall to adjust the flow.
Electric: The movement of the electric stop valve disc is controlled by an electric actuator, which is usually used in automation systems.
Pneumatic: The pneumatic actuator controls the opening and closing or adjustment of the valve disc through compressed air.
Globe stop valve controls the flow of fluid by adjusting the position of the valve disc. When the valve disc is raised, the fluid flow increases; when the valve disc is lowered, the flow decreases until it is completely closed. Due to this design, Globe Valve is suitable for precise flow regulation and is widely used in industrial systems that require flow regulation, such as liquid and gas flow control and high pressure and high temperature environments.