Advantages and disadvantages of globe valve

Definition of globe valve&#;

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The opening and closing member (valve new) driven by the valve stem, along the valve seat (sealing surface) axis to do linear lifting movement of the valve is called a globe valve.

Globe valve is generally driven by the drive parts (handwheel, stem, valve body, valve cover, valve flap (closure) and packing assembly, and other major components. The handwheel is connected to the valve stem, and the valve flap is driven by the valve stem, so that the valve flap moves reciprocally along the direction of the valve seat axis, thus making the pipeline connected or cut off.

The globe valve is widely used, mainly for higher pressure and smaller caliber occasions, generally only produced to DN400 (NPS 16), the larger diameter specifications only for special pipelines. For example, a large oxygen pipeline, due to the existence of other valves friction is prone to static fire, so the use of a large-diameter stainless steel globe valve.

 

The working principle of the globe valve&#;

Globe valve stem generally do rotary lifting movement, handwheel fixed in the top of the stem. When the handwheel is rotated clockwise, the stem threads rotate down, the valve sealing surface and the valve seat sealing surface in close contact, and the shut-off valve closes; when the handwheel is rotated counterclockwise, the stem threads rotate up, the valve sealing surface and the valve seat sealing surface disengage, the shut-off valve open.

 

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 only one sealing surface on the valve body and valve flap, small sealing area, saving valuable materials, low cost, and therefore better manufacturing process, easy maintenance.

#2 The seal surface wear and abrasion are light, good sealing. No relative sliding between the valve flap and body sealing surface when opening and closing (except for the conical sealing surface), so the wear and abrasion are not serious, good sealing performance, and long service life.

#3 Opening height is small, generally only 1/4 of the diameter of the valve seat channel, compact structure, saving installation space.

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

#5 High-pressure rating: Globe valves can handle high-pressure applications because of their unique design. This makes them ideal for use in piping systems where pressure is a critical factor.

#6 Good shutoff capability: Globe valves have a good shutoff capability, which is particularly useful in applications where tight shut-off is required. This helps ensure that the valve prevents the flow of fluids in both directions.

#7  Versatility: Globe valves can be used with a wide range of fluids, including gases, liquids, and slurries. This makes them useful in a variety of industries, including petrochemical, manufacturing, refining, and water treatment.

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

Disadvantages of globe valve:

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

#2 Size and weight: Globe valves are generally larger and heavier than many other types of valves, which can make them more difficult to install and require larger support structures.

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

#4 Maintenance: Globe valves have multiple internal components that can wear or become damaged over time, requiring 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, which can limit their suitability for certain situations.

Globe valves can be classified based on different criteria. Here are some of the common classifications of globe valves:

#1. Based on design: Globe valves can be classified based on their design, such as T-pattern, Y-pattern, and angle pattern. Each design has unique characteristics, such as better flow control, reduced pressure drop, or being more suitable for high-pressure applications.

#2. Based on valve body material: Globe valves are made from different materials, including stainless steel, carbon steel, bronze, brass, and cast iron. The material used for the valve body and other components depends on the type of fluid to be handled, pressure, temperature, and durability requirements.

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

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

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

The following application conditions are 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.

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#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 be prone to failure.

#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 are effective in controlling process conditions, such as 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 the flow of fluids and are reliable in controlling pressure and temperature conditions in a piping system.

Valves are mechanical or electro-mechanical devices commonly found in a myriad of industrial processes, manufacturing, and maintenance operations.   These devices regulate the movement of fluids (liquid, air, gas, etc) via pipes and/or tubes, as well as from tanks or other containers. Moreover, these devices are primarily classified according to their function, design, and size.

Among all types of valves, the ball valve and globe valve are two of the most used valves in the industrial industry.  In this article, we will learn about the advantages and disadvantages of both the ball valve and globe valve, as well as a comparison between the two types of valves.

Ball Valve Advantages and Disadvantages

The ball valve provides a quarter-turn operation to open or close. This conventional type of valve consists of a hollow rotary ball or disk, usually the size of the pipe, and a stem that connects it to the lever. The hollow ball and the lever of the valve rotate similarly and are parallel to each other, allowing the flow of fluids in the inlet and outlet in the valve body. Ball valves are used in any industrial applications that require fluid flow shut off.

Advantages

Generally, ball valves operate with efficiency and a great deal of durability. As such, they tend to be cost-effective, low maintenance, and usually a durable choice for the savvy operator.

With the hollow rotary ball mechanism, the ball valve provides low-pressure drop and high flow capacity. Disturbances in the flow of fluids such as turbulence and resistance are minimal. Aside from that, ball valves also provide a bubble-tight seal with little torque and lack the need for routine lubrication.

Generally, ball valves provide high durability. They can provide ten-plus years of reliable use when fit to the right application. Moreover, materials selection in manufacturing ball valves enables them to withstand high pressure and lessens the wear due to environmental conditions such as corrosion and temperature.

Compared to the cost of ball valves vs a globe valves, it is extremely affordable. In addition, ball valves are a cost-effective option due to their lower maintenance requirements. This mainly derives from the quarter-turn mechanism of the ball valve. This mechanism makes it less prone to wear and tear. Another reason is that the use of a pivot concentrates all friction forces to one part of the valve, thus conserving the other parts. Moreover, ball valves typically weigh comparably little and take up a small footprint vs. globe valves.

Disadvantages

The ball valve&#;s propensity to blockage, poor throttling capacity and space considerations are reasons that an engineer might wish to specify another valve.

It is not recommended to use ball valves on thick fluids such as slurries. Any thick fluid that passes through the ball valves may solidify, clog the flow and pile up in the cavities of the valve. This requires more maintenance and in the worst case scenario may render the valve inoperable and require replacement.

Ball valves should only be utilized in either a completely open or fully closed state and should not be used for long-term throttling. The partially exposed seat of the ball valve may be vulnerable to degradation and deformation in a throttling position due to high-velocity flows.   For this reason, continuous throttling applications should never rely on a ball valve.

Since the mechanism involves a quarter-turn handle, engineers should consider available space prior to specifying a ball valve. An exposed handle in an area of egress or in the path of other equipment may create a hazard or operability issue.

Globe Valve Advantages and Disadvantages

The globe valve provides a multi-turn valve design starts, stops, and regulates the flow of fluids. The design is based on a disk, also called the plug, which lowers onto a seat, gradually restricting the flow as the valve closes. Globe valves are primarily used in industrial applications that require fluid throttling vs ball valves that are not generally recommended for throlling. One important feature is the valve seat orients parallel to the direction of flow.

Advantages

Globe valves provide good shutoff capability, good throttling capability, high reliability, and a variety of flow configurations.

The globe valve&#;s plug or disc adjusts from fully open to fully closed to match the needed flow rate for a specific application, making them a great choice for precise regulation control. The flow restriction through the valve increases with the distance between the plug and the seat in the body.           

Since globe valves find service in partially open configurations, they provide ideal throttling capabilities. Moreover, these valves are easy to maintain and resurface the seats and are specifically designed for throttling operation.

Globe valves travel a short distance during operation. Thus, fewer turns are required to fully open and close the plug or the disc. This saves time and wear on the valve parts. In a well-designed globe valve, high reliability ensues.

The glove valve provides three primary body designs (Tee, Angle, and Wye). Each body design provides a different flow path.

Tee is the most common type of globe valve. Angle globe valves can handle the &#;slugging effect&#; with its inlet and outlet at a 90° angle allowing fluid to flow in a single 90° turn. Wye valves have a 45° angle between the seat and stem providing a straighter flow path when fully open. This straight flow path translates into the lowest flow resistance among the three designs. 

Disadvantages

Some disadvantages that the engineers must consider when specifying a globe valve are the uni-directional requirement, high-pressure drop, and heavy weight.

The unidirectional requirement of globe valves means they can only start, stop and regulate the fluid flow in one direction.

Using globe valves in industry applications often results in high-pressure drops. Globe valves are specifically designed to change of direction of flowing fluid, thus increasing pressure drop. This pressure drops further increases during throttling applications.

Compared to other valve types, globe valves usually provide heavier weight and bulk. Subsequently, this requires greater force or a larger actuator to operate its mechanism.

Ball Valve vs. Globe Valve

After extensively discussing the advantages and disadvantages of using Ball and Globe valves in industrial processes, let&#;s consider these factors and visit the table that compares key selection parameters.

Parameter Ball Valve Globe Valve Main Function Designed primarily for shut-off and commodity-type flow applications. Designed for throttling action, such as regulating the flow of fluid. Operating Mechanism Bidirectional. The stem connects to a lever which is easier to operate with its 90° quarter-turn mechanism. Unidirectional. The stem connects to an external handwheel which moves the plug for fluid flow regulation. Visual Detection The position of the lever allows for the visual detection of the open or closed condition. The hollow ball and lever move in a parallel fashion. Despite being unidirectional, it is tough to detect the flow regulation and its open and closed state. Durability Ball valves are generally more durable and less susceptible to damage. Globe valves are generally less durable and more prone to leakage and cavitation. Cost With its basic mechanism, it is typically less expensive than a globe valve. With its body design and bulkiness, it is usually more expensive than a ball valve. Common Industrial Applications Potable water systems, Oil and gas, Flow regulation, Manufacturing processes Cooling water systems, Fuel oil systems, Feedwater, Chemical feed systems, Steam vents and drains Ball Valve vs. Globe Valve Overview

A ball valve and a globe valve both control fluid flow, but their distinct designs suit various uses. Ball valves are simple to operate and inexpensive, and they provide an easy way to identify the valve&#;s opening status. Despite its excellent shut-off mechanism, it regulates flow poorly.

On the other hand, globe valves may precisely control the flow and have great flow regulation capabilities yet are less convenient to use than other types of valves.

Which is best? There&#;s no right answer to this question. The answer to the ball valve vs. globe valve debate depends on its intended use. It is crucial to select the most suitable type of valve for the application to optimize performance and reliability.