Globe valves control the flow of fluids in piping systems. They are widely employed in various industries for their versatility and ability to provide accurate flow regulation.
Design and Operation
Globe valves consist of a valve body, a plug or disc (also known as the globe), a stem, and an actuator. The plug or disc is positioned perpendicular to the flow path. When the valve is fully open, the plug is lifted away from the seat, allowing fluid to pass through. Conversely, when the valve is closed, the plug is pressed against the seat, blocking the flow.
Globe valves operate by linear motion, meaning the stem moves up and down to control the position of the plug relative to the seat. Globe valves can be operated manually using a handwheel or automatically using electric, pneumatic, or hydraulic actuators.
Applications of Globe Valves
- Flow Regulation: Globe valves are primarily used for flow regulation and throttling applications where precise control of flow rate is required. They offer the ability to adjust the flow by varying the position of the plug relative to the seat, allowing for fine-tuning of flow rates.
- Isolation and Shutoff: While globe valves are primarily designed for throttling, they can also be used for isolation and shutoff applications. However, compared to gate valves, they typically offer less efficient sealing when fully closed and are, therefore, not as commonly used for strict shutoff requirements.
- Boiler Feedwater Systems: Globe valves are commonly used in boiler feedwater systems in power plants and industrial facilities. They regulate water flow into boilers at various pressures and temperatures, helping maintain optimal boiler performance.
- Heating, Ventilation, and Air Conditioning (HVAC): Globe valves are utilized in HVAC systems to control hot or chilled water flow through heating and cooling coils. They enable precise temperature control and flow modulation to maintain comfortable indoor conditions.
- Steam and Process Systems: In steam and process piping systems, globe valves control the flow of steam, gases, and various process fluids. They provide reliable flow regulation and can handle high pressures and temperatures encountered in industrial processes.