DN80 WCB PN16 Flange End Globe Valve The Cooling Water System
Globe Valve Parts
Globe valve contains many different parts like bonnet, body, stem, seat, plug, etc. Let’s discuss all of them.
The body is the primary pressure boundary of the valve. It keeps all the internal parts together inside it. It is connected with a bonnet.
The bonnet is connected with the body through bolts or screwed. It is a secondary pressure boundary. The stem moves vertically inside the bonnet and opens and closes the valve. It contains packing to eliminate leaking.
The plug is the element that throttles the flow of fluid. It is connected with the stem and opens and closes by stem movement. In the close condition, it fits on the seat and stops the flow of fluid.
The stem is the connector between the actuator and plug. By rotating the actuator we can open and close the valve by plug movement.
The seat is the part of the valve where the plug fits and stops the flow of fluid.
|SPECIFICATIONS FOR STEEL GLOBE VALVES
|Pressure rating and size:
|DN40 to DN600
||Body : A216-WCB,A325-LCB,A217-WC6,CF8,CF8M
|Disc : A105+13Cr, SS304, SS316
|Stem : A182+F6a,A182-F6a
||stopcock for water
||-20 to 425°C
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 and disadvantages of Globe valves
- 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
- 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
Typical Applications of Globe valves
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
We choose suitable wood cases according to different valves and arrange skilled workers to pack in case of bruise. Long term cooperated forwarder will book space, clear customs and transport for us without delay. There are three ways for transportation, by sea, by air and by train. We will arrange transportation according to customers' needs.
Delivery Details: According to the order, 7~60days