WCB Body Outside Screw 8'' 150#, Handwheel Operated Globe Valve

Specification

Globe Valve, WCB Body, XU Trim (13% chromium trim), outside screw and yoke, bolted bonnet,

flanged ends Ansi 150#, Handwheel operated

Size 2″ – 12″ (DN50 – DN300)

How Does It Work?

Globe valves are usually controlled by an automatic actuator that regulates the flow by moving the

disk perpendicular to the seat. Globe valves can control fluid flow either manually or automatically.

The right angles produce less leakage than you’d find in a gate valve.

When turned in a clockwise motion the disk lowers to the seat which physically obstructs the

liquid’s path, either reducing it or blocking it completely, depending on how low the disk moves.

Types of Globe Valves

There are various globe valve types and designs, each with there own pros and cons.

Globe Valve Arrangement Based on Fluid Flow

Disks that close against the direction of the fluid flow are great if you need a quick opening

valve. Disks that close with the direction of the fluid flow are a better a choice if you need a

quick closing valve.

Globe valves

A Globe valves is a linear motion valve and are primarily designed to stop, start and regulate flow.

The disk of a Globe valve can be totally removed from the flowpath or it can completely close the flowpath.

Conventional Globe valves may be used for isolation and throttling services. Although these valves exhibit slightly

higher pressure drops than straight=through valves (e.g., gate, plug, ball, etc.), they may be used where the pressure

drop through the valve is not a controlling factor.

Because the entire system pressure exerted on the disc is transferred to the valve stem, the practical size limit for these

valves is NPS 12 (DN 300). Globe valves larger than NPS 12 (DN 300) are an exception rather than the rule. Larger

valves would require that enormous forces be exerted on the stem to open or close the valve under pressure. Globe

valves in sizes up to NPS 48 (DN 1200) have been manufactured and used.

Globe valves are extensively employed to control flow. The range of flow control, pressure drop, and duty must be

considered in the design of the valve to avert premature failure and to assure satisfactory service. Valves subjected

to high-differential pressure-throttling service require specially designed valve trim.

Generally the maximum differential pressure across the valve disc should not exceed 20 percent of the maximum

upstream pressure or 200 psi (1380 kPa), whichever is less. Valves with special trim may be designed for applications

exceeding these differential pressure limits.

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, 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

The following are some of the typical applications of Globe valves:

• Cooling water systems where flow needs to be regulated
• Fuel oil system where flow is regulated and leaktightness is of importance
• High-point vents and low-point drains when leaktightness 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