Globe Valve

Globe Valve

A globe valve regulates flow in a pipeline. It is used to control or stop the flow of liquid or gas through a pipe. Globe valves are named for their spherical body shape with the two halves of the body being separated by an internal baffle.

Working principle

When the valve is actuated to open the disk will perpendicularly move away from the seat. When compared to a gate valve, a globe valve generally yields much less seat leakage. This is because the disk-to-seat ring contact is more at right angles, which permits the force of closing to tightly seat the disk.

Globe valves can be arranged so that the disk closes against or in the same direction of fluid flow. When the disk closes against the direction of flow, the kinetic energy of the fluid impedes closing but aids opening of the valve.

When the disk closes in the same direction of flow, the kinetic energy of the fluid aids closing but impedes opening. This characteristic is preferable to other designs when quick-acting stop valves are necessary.

Advantages and disadvantages and applications of Globe valves

ADVANTAGES

• Good shutoff capability
• Moderate to good throttling capability
• Shorter stroke (compared to a gate valve)
• Available in tee, wye, and angle patterns, each offering unique capabilities
• Easy to machine or resurface the seats
• With disc not attached to the stem, a valve can be used as a stop-check valve

DISADVANTAGES

• Higher pressure drop (compared to a gate valve)
• Requires greater force or a larger actuator to seat the valve (with pressure under the seat)
• Throttling flow under the seat and shutoff flow over the seat

applications of Globe valves

• Cooling water systems where flow needs to be regulated
• Fuel oil system where the flow is regulated and leak-tightness is of importance
• High-point vents and low-point drains when leak-tightness and safety are major considerations
• Feedwater, chemical feed, condenser air extraction, and extraction drain systems
• Boiler vents and drains, main steam vents and drains, and heater drains
• Turbine seals and drains
• Turbine lube oil system and others