All You Need To Know About Globe Valves

Globe valves are valves with a globular body with a linear motion valve. The shape of the body has changed, though the function principle remains the same. Globe valves offer precise throttling ability for high pressure systems which is advantageous for some uses. The low flow coefficient is the biggest disadvantage for some users when the valve operating time is longer and the operator has to manually check whether the valve is completely open or closed.  Globe valves are widely used in systems that run on a wide range of temperatures, systems that require frequent stroking and vacuum.

Globe valves are used for gas as well as liquid systems. They are not advisable to be used for slurry systems as the material may become entrapped in the cavity and disable the valve operations. They can be used in a variety of applications as long as the pressure and temperature are within the limits. The space between the disk and the seat changes which allows the liquid to flow. Sometimes the direction of the flow changes which causes a change in pressure. To help maintain a tight seal, the globe valve is installed with a vertical stem and fluid stream connected to the pipe above the disk.

The globe valve is used where the flow or the pressure is to be controlled in a system. The globe valve can be operated in any position between open and close that offers precision control. This is possible due to the perpendicular movement of the disk away from the seat. The gradual change in the spacing allows the operator to precisely control the flow. 

Construction of the Globe valve

The globe valve is designed in three body types: angle design, Y-design and Z-design.  The trim consists of a disk and seat ring. The disk lowers into the seat in the center of the valve to stop the flow. The position of the disk in relation to the seat allows or restricts the flow. The handwheel and disk are connected by a stem which is threaded and fits in the valve bonnet.  The seat of the globe valve may be integrated or screwed into the body of the valve. The valve is open or closed by the valve actuator which operates the stem and disk.

Advantages of Globe Valve

• The brass globe valve is highly durable and safe
• Fast acting
• The control of flow is precise
• Can be easily used in high pressure systems

Disadvantages of Globe valves

• The opening of the disk assembly is large
• There is high head loss
• Globe valve is much heavier than other valves
• The coefficient of flow is low
• The mounting of the disk on the stem is cantilevered

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