Basics of Globe Valves

Globe valves consist of a movable disk-type element and a stationary ring seat in a generally spherical body. The valve stem moves a globe plug relative to the valve seat.

Basics of Globe Valves

The globe plug can be at any position  between  fully opened  and fully closed  to control  flow through  the valve. The globe and seat construction gives the valve good flow regulation characteristics.

Turbulent  flow past the seat and plug, when the valve is open, results in a relatively  high pressure drop, limited flow capacity, and low recovery.

Best Suited Control: Linear and Equal percentage

Recommended Uses:

Applications requiring:

• Precise flow regulation

• Frequent and wide throttling operation

• Suited to very high pressure drops

Advantages:

• Efficient and precise throttling

• Accurate flow control

Disadvantages:

• Low recovery and relatively low coefficient of flow (Cv).

• High pressure drop, higher pump capacity and system wear.

• More expensive than other valves.

• The sealing  device  is  a  plug  that  offers  limited  shut-off  capabilities,  not  always meeting bubble tight requirements.

Applications:

• Suitable for most liquids, vapors, gases, corrosive substances

• General sizes available are 1/2″ to 8″.

• Pressure limitations are relatively high, ranging from 1480 to 1500 psi, dependent on materials of construction, size and temperature.

• Minimum  and maximum  temperatures  are also very broad ranging  from -425°F  to 1100°F, depending again on the materials of construction.

• Depending on the specific construction and application, the globe valve may comply with ASME class II, III, IV, V or VI shut-off requirements.

• Easily automated and available with positioners, limit switches, and other accessories.

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