A globe valve is a type of valve used for regulating flow in a pipeline, consisting of a movable disk-type element and a stationary ring seat in a generally spherical body.

Globe Valves are named for their spherical body shape with the two halves of the body being separated by an internal baffle. This has an opening that forms a seat onto which a movable plug can be screwed in to close (or shut) the valve. The plug is also called a disc. In globe valves, the plug is connected to a stem which is operated by screw action in manual valves. Typically, automated valves use sliding stems. Automated globe valves have a smooth stem rather than threaded and are opened and closed by an actuator assembly. When a globe valve is manually operated, the stem is turned by a hand wheel.

Globe valves are used for applications requiring throttling and frequent operation. For example, globe valves or valves with a similar mechanism may be used as sampling valves, which are normally shut except when liquid samples are being taken. Since the baffle restricts flow, they're not recommended where full, unobstructed flow is required.

Body-Bonnet Connection
The body and bonnet of Class 150 to Class 900 valves are usually with studs and nuts. And the body and bonnet of Class 1500 to Class 2500 valves are usually of pressure seal design.

Body-Bonnet Gasket
Stainless steel + flexible graphite wounded gasket is used for Class150 and Class 300 globe valve. Stainless steel + flexible graphite wounded gasket is used for Class 600, and ring type joint gasket is optional. Ring joint gasket is used for Class 900 globe valve. Pressure seal design is used for Class 1500 to Class 2500 globe valve.

Operation
Hand wheel and gearbox operation are applied for globe valve. Chain wheel and electric is available if required.

Packing Seal
Molded flexible graphite is used for packing material. PTFE or combined packing material can be applied if required.

The internal surface of the stuffing box, of which area is contacted with the packing, is of excellent finished (Ra 3.2μm). The stem surface, contacting with the packing, should be rolled and pressed after being precisely machined, so as to reach high finish and compactness (Ra 0.8μm) and ensure the reliable tightness of the stem area.

Belleville Spring Loaded Packing
If required, Belleville spring loaded packing can be applied to enhance the durability and reliability of the packing seal.

Back Seat
All our globe valves have the back seating design. In most cases, the carbon steel globe valve is fitted with a renewable back seat.

For stainless steel globe valve, the back seat is machined directly in the bonnet or machined after welding. When the globe valve is in fully open position, the sealing of the back seat can be very reliable. However, as per the requirement of design standards, it is not advisable to add or change packing by the mean of back seating when the valve is under line pressure.

Seat
For carbon steel globe valve, the seat material is usually forged steel. The sealing surface of the seat is overlay welded with hard alloy specified by customer. Renewable threaded-in seat is applied for globe valve NPS≤10, and welded-on seat is optional.

Welded-on seat is used for NPS ≥ 12 carbon steel globe valves. For stainless steel globe valve, integral seat is usually adopted, or hard alloy welding directly integrally. Threaded-in or welded on seat is optional for stainless steel globe valves.

Stem
The stem is of one-piece forged steel. The minimum diameter of the stem shall be as per the standard requirements.

Stem Nut
Usually, the stem nut is made of copper alloy. It can be made of ASTM A439 D2 if required. For large sized globe valve, rolling bearing is fitted at the two sides of stem nut in order to minimize the open and close torque of the globe valve.