Advantages and disadvantages of globe valve

Definition of Globe Valve:

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The opening and closing element (valve plug) driven by the valve stem, along the valve seat (sealing surface) axis to do linear lifting movement, makes the valve known as a globe valve.

A globe valve generally consists of drive parts (handwheel, stem, valve body, valve cover, valve disc, and packing assembly). The handwheel connects to the valve stem, driving the valve disc to move reciprocally along the direction of the valve seat axis, thereby connecting or cutting off the pipeline.

The globe valve is widely used, mainly for higher pressure and smaller caliber occasions, generally produced up to DN400 (NPS 16). Larger diameter specifications are for special pipelines. For instance, a large-diameter stainless steel globe valve is used in oxygen pipelines to avoid static fires caused by friction from other valves.

The Working Principle of the Globe Valve:

The globe valve stem generally performs a rotary lifting movement with the handwheel fixed at the top of the stem. When the handwheel is rotated clockwise, the stem threads rotate down, causing the valve sealing surface and the valve seat sealing surface to come into close contact, closing the valve. Conversely, when the handwheel is rotated counterclockwise, the stem threads rotate up, disengaging the valve sealing surface from the valve seat sealing surface, opening the valve.

The Advantages and Disadvantages of the Globe Valve:

The Advantages of the Globe Valve:

#1 Compared with the gate valve, the globe valve structure is simpler, usually featuring only one sealing surface on the valve body and valve disc. This small sealing area saves valuable materials, lowers costs, enhances the manufacturing process, and makes maintenance easier.

#2 The seal surface wear and abrasion are light, offering good sealing. No relative sliding occurs between the valve disc and body sealing surface when opening and closing (except for the conical sealing surface), contributing to less serious wear and abrasion, good sealing performance, and a long service life.

#3 The opening height is small, generally only 1/4 of the diameter of the valve seat channel. This compact structure saves installation space.

#4 Precise flow control: Globe valves are particularly useful for applications requiring precise control of fluid flow. They can be adjusted to provide a wide range of flow rates, making them suitable for various industrial applications.

#5 High-pressure rating: Globe valves can handle high-pressure applications due to their unique design, making them ideal for piping systems where pressure is critical.

#6 Good shutoff capability: Globe valves offer good shutoff capability, useful in applications where tight shut-off is necessary. This helps prevent fluid flow in both directions.

#7 Versatility: Globe valves can be used with various fluids, including gases, liquids, and slurries. This makes them useful across multiple industries, including petrochemical, manufacturing, refining, and water treatment.

#8 Long lifespan: Globe valves are durable and can last many years with proper maintenance, saving money over the long term. They are also less prone to leakage, preventing damage to equipment or surrounding areas.

Disadvantages of Globe Valve:

#1 Pressure drop: Globe valves create a significant pressure drop across the valve when fully open due to their inherent design. This can reduce the system's efficiency and require additional energy to maintain flow rates.

#2 Size and weight: Globe valves are generally larger and heavier than many other valves, making them more challenging to install and requiring larger support structures.

#3 Cost: Globe valves can be more expensive than other valve types due to their complexity and the precision required for manufacturing and installation.

#4 Maintenance: Globe valves have multiple internal components that can wear or become damaged over time, necessitating more frequent maintenance than simpler valve types.

#5 Limited suitability for high flow rates: Globe valves can be prone to cavitation and erosion in high-flow applications, limiting their suitability for certain situations.

Classification of Globe Valves:

#1. Based on design: Globe valves can be classified into T-pattern, Y-pattern, and angle pattern designs. Each design has unique characteristics, such as better flow control, reduced pressure drop, or higher suitability for high-pressure applications.

#2. Based on valve body material: Globe valves are made from various materials, including stainless steel, carbon steel, bronze, brass, and cast iron. The material used depends on the fluid type, pressure, temperature, and durability requirements.

#3. Based on the valve stem: Globe valves can be classified according to the type of valve stem used, such as rising stem, non-rising stem, or rotary stem. The stem type determines how the valve disc or plug is moved to regulate or shut off the fluid flow.

#4. Based on the number of ports: Globe valves can also be classified by the number of ports, such as single-port or double-port. Single-port globe valves have one inlet and one outlet port, while double-port, or 3-way, globe valves have three or more ports for more complex flow path configurations.

#5. Based on the operating mechanism: Globe valves can be classified by their operating mechanism, such as manual, electric, pneumatic, hydraulic, or solenoid-operated. The operating mechanism determines how the valve is opened or closed based on the application requirements.

Application Conditions Suitable for Globe Valves:

#1. High-pressure applications: Globe valves are suitable for high-pressure piping systems where there is a high risk of fluid escaping.

#2. Precise flow control: Globe valves are ideal for controlling the flow rate of process fluids with high precision.

#3. High-temperature applications: Globe valves can perform well in high-temperature environments where other valve types may fail.

#4. Corrosive or abrasive fluids: Globe valves are suitable for use with corrosive or abrasive fluids due to the availability of valve components with specific material compatibility.

#5. Liquid services: Globe valves are commonly used in liquid services, such as water treatment plants or chemical processing facilities.

#6. Process control: Globe valves effectively control process conditions like pressure, temperature, or flow rate, where accuracy is essential.

#7. High-viscosity fluids: Globe valves can handle high-viscosity fluids, such as slurries or lubricants, with a higher degree of precision.

Overall, globe valves are ideal for applications requiring precise control, good shutoff capability, and adaptable flow rates. They provide accurate adjustments in fluid flow and are reliable in controlling pressure and temperature conditions in a piping system.

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The Benefits of Using Globe Valves

The globe valve is a linear motion valve used to stop, start, and regulate fluid flow. When considering its use in industry, the reasons for choosing this type of valve are essential. This article discusses these points.

Key Points:

• What is a globe valve
• The advantages and disadvantages of globe valve
• The application of globe valve

1. What is a Globe Valve

A globe valve is a linear motion valve mainly used to stop, start, and adjust the flow. The valve disc of a globe valve can be completely removed from the flow channel, or it can be completely closed. Conventional globe valves can be used for isolation and throttling applications. Although these valves have a slightly higher pressure drop than straight-through valves (such as gate valves, plugs, ball valves, etc.), they can also be used where the pressure drop through the valve is not a controlling factor.

The globe valve is excellent for throttle flow control. Closing is achieved by moving the disc in the direction of the fluid rather than passing through the fluid like a gate valve. The flow pattern through the globe valve changes the flow direction, resulting in greater resistance to flow, causing a higher pressure drop. The globe valve is suitable for high-pressure steam operation. Our globe valves are factory-made with high-quality materials ensuring long-term use.

Globe valve refers to a valve whose valve plate moves along the center line of the valve seat. According to this form of valve movement, the change in valve seat opening is proportional to the valve stroke. Because the opening or closing stroke of the valve stem is relatively short, it offers a very reliable cut-off function, perfect for flow regulation. Globe valves can be divided into external and internal thread types based on thread size. Also, they can be categorized into linear and angular types according to the flow direction. Globe valves can be divided into the DC type and angle type based on flow direction. Additionally, globe valves can be classified into packing seal type and bellows seal type according to their sealing form.

2. The Advantages and Disadvantages of Globe Valve

Advantages:

(1) Close function

(2) Moderate to good throttling ability

(3) Shorter stroke (compared to gate valve)

(4) Available in all modes, each providing unique capabilities

(5) Seats that are easily refurbished by machines or surfaces

(6) If the disc is not attached to the valve stem, the valve can be used as a check valve

Disadvantages:

(1) Higher pressure drop (compared to gate valve)

(2) Need more force or a bigger actuator to install the valve (pressure under the valve seat)

(3) Throttling flow is below the valve seat, and closing flow is above the valve seat.

(4) High head loss from two or more right-angle turns of flowing fluid.

(5) Large-diameter valves require considerable power to operate and are particularly noisy in high-pressure applications

(6) The large opening required for the valve disc assembly, heavier weight than other valves with the same flow rate, and the overhanging valve disc is installed on the valve stem.

3. The Application of Globe Valve

• The following are some typical applications of globe valves:
• Cooling water systems requiring flow adjustment
• Fuel system flow regulation and tightness are very important
• High point vents and low point drainage when tightness and safety are the main considerations
• Water supply, chemical raw materials, condenser air extraction, and extraction drainage systems
• Boiler exhaust and drain, main steam exhaust and drain, heater exhaust
• Turbine seal and drainage
• Turbine lubricant system
• That’s all about the advantages and disadvantages of globe valves, do you get it?

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