In this article, you will learn about the globe valve, when to use it, and globe valve actuator options based on the power source available. Globe valves are linear valves whose closing membrane is a disc or plug that opposes the flow inside the valve body, allowing more flow as it moves away from the seat. The seat is a ring installed in the center of the valve body, this design creates high energy loss due to the change in the flow direction and shortens the valve effective stoke.
Globe Valve Parts diagram:
They get their name from the shape of their spherical body. These valves can have resilient or metallic seats and are unidirectional as they must be installed with the pressure side under the seat. Normally in industry, they are flanged. Also, they are offered in other connections such as threaded or welded.
Globe valves are used as control valves, their design allows them to have excellent control characteristics since their flow coefficient curve provides more proportional values with the opening percentage due to their linear characteristics.
Globe valves are mainly used for regulation purposes. They can be considered general purpose flow control valves and can be seen in pumping stations as pressure reducing valves, pressure relief valves, to control the inlet flow of ponds, among others. They are also used in the oil and gas and chemical industries, in fire water stations, and can also be used as stop check valves.
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Globe Valve Actuators
Globe valves, like any other type of valve, need a power source to be operated. The energy required depends mainly on the design and the pressure differential across the valve. A Globe Valve Actuator can be selected depending on the type of energy available to the user.
When pneumatic pressure is available, Globe valve actuators can be:
Double-acting linear pneumatic actuators, Cowan Series A
Single-acting linear pneumatic actuators, Cowan Series AS
Single and double-acting linear pneumatic actuators for control, Cowan Series AT
Single and double-acting linear pneumatic actuators for control, Cowan Series CDA
When hydraulic pressure is available, Globe valve actuators can be:
Double-acting linear hydraulic actuators, Cowan Series ML
Single-acting linear hydraulic actuators, Cowan Series MS
When electric power is available:
Double and single acting linear electrohydraulic for isolation and controls, Cowan Series E2H
Valve Standards
Valve standards include:
- API STD 623 – Steel Globe Valves—Flanged and Butt-welding Ends, Bolted Bonnets
- PIP PNSMV024 – Stainless Steel Globe Valve Descriptions
- PIP PNSMV034 – Bronze and Iron Globe Valve Descriptions
- PIP PNSMV004 – Carbon Steel Globe Valve Descriptions
- This Practice describes the requirements for carbon steel globe valves.
