Globe Valves by John Valves
The flow path through globe valves follows a changing course. This results in increased resistance to flow and higher pressure drop. Unlike the perpendicular seating seen in gate valves, globe valve seating is parallel to the line of flow. All contact between the seat and disc ends when flow begins.
Globe valves feature shorter disc travel. There are fewer turns required to operate globe valves saving you considerable time, work and wear on valve parts.
Globe valves are not recommended when resistance to flow and pressure drop is objectionable. Though, they are generally ideal for throttling and preferable when a valve gets operated frequently.
We locally manufacture and supply a wide range of globe valves, including:
- Bronze globe valves
- Cast iron globe valves
- Cast and forged steel globe valves
- High-pressure globe valves (up to 6200kpa)
Bronze Globe Valves
Our range of low-cost bronze globe valves come with screwed bonnets and integral seats making them ideal for general-purpose applications requiring throttling control and isolation of flow. These may include hospital services, canteen equipment and agricultural instrumentation, for example.
The seating faces of the disc and body may be easily reconditioned after extensive use.
Soft Seat Globe Valves
The John 101 and 102 bronze globe valves have union bonnets, renewable composition discs and integral seats. They are suitable for isolation duties on medium/low-pressure steam and hot water services. They are also suitable for regulation and isolation duties on cold water, air, oil, gas and other liquids (not injurious to copper alloys).
Application areas include hospital equipment, canteen appliances, heating systems and industrial processes.
Stainless Steel Trim Globe Valves
Our range of stainless steel trim globe waves includes the John 501 and 502. They feature a stainless steel disc and seat with precision lapped faces. This allows for easy inline refurbishment or replacement if necessary. The valves feature a union type metal to metal bonnet seal which provides pressure-tight sealing when in service. With a locking screw, dismantling for maintenance purposes is simple.
Their brass stems come with accurately machined Acme threads. They feature an effective and reliable stem sealing using non-asbestos packing in a substantial stuffing box.
Cast Iron and Cast Carbon Steel Globe Valves
Our range of cast iron and carbon steel globe valves are of simple, robust design. Their specified working conditions cover a wide range of industry applications.
Forged Carbon Steel Globe Valves
Our forged carbon steel globe valves include the John Fig 245. These outside screw globe valves are designed for high pressure and/or high-temperature service. They are supplied as standard with a stellite-faced valve disc and body seat.
Frequently Asked Questions About Globe Valves
Got questions? Below are some of the questions we get asked often about globe valves.
It is a linear motion valve used for stopping, starting and regulating flow. When the valve opens and closes, its disc moves perpendicularly to the seat. This characteristic provides this type of valve with optimal throttling ability.
A globe valve’s disc can be set up to close against the flow or with the flow. When closing with the flow, kinetic energy is created by the fluid. This kinetic energy assists with the closing but hinders the opening. In cases where quick-acting stops are needed, this operation of globe valves is preferable.
Where the valve is set up to close against the flow, we see the same action, but in reverse. The fluid’s kinetic energy assists with the opening and hinders the closing. This is preferable in cases when quick-acting starts are needed.
The preferred direction of flow is marked on the body of the valve usually with a cast flow direction arrow.
In a nutshell, this type of valve is of use where flow control and leak tightness are essential. You can find globe valves in high-point vents, low-point drains and many services where pressure drop is non-consequential.
There are several advantages of globe valves, including:
- More effective shut off in comparison to the gate valve
- Less wear and tear of seat and disc; ideal for frequent operation
- Easy access to seat and disc from the top of the valve makes for easy maintenance and repairs
- Shorter stroke length results in faster operation
Depending on the service needs, globe valves may not be suitable for one or more of the following reasons:
- A globe valve consists of a few right-angle turns resulting in higher pressure loss
- Globe valves generally weigh more than other valves with the same pressure rating
- In comparison to a gate valve, a globe valve is more costly