How does an angle globe valve work?

Industrial valves are found everywhere &#; be it in an industrial setting or a domestic setting, valves play a crucial role in making our everyday lives easier. Globe valves are one of the most common industrial valves that are commonly found in steam services, oil and gas pipelines, turbine seals, and boiler vents.

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This article will give detailed explanations of what a globe valve is, the parts of the valve, and how it works.

What is a Globe Valve?

A globe valve is an industrial valve that is designed to stop, start, or regulate flow. It is a linear motion valve where the internal disc can be adjusted to tinker with the flow of media &#; this assures the complete flow or obstruction of a particular medium. 

Unlike a few other industrial valves, globe valves are ideal for throttling and controlling flow. Globe valves can also be used for the isolation of media. They are mainly employed in small piping systems to ensure complete control over the flow of a medium.

The main working principle of a globe valve involves the movement of a disc that acts as the closure member. By moving the disc in or out of the seating surface, one can control the movement of media in a pipeline. These valves form a cavity &#; a globular-shaped cavity &#; around the port region, and hence they acquire the name.

A qualified globe valve manufacturer will consider a multitude of factors like pressure drop, frequency of usage, and the choice of media before designing a globe valve.

Types of Globe Valves

Globe valves feature a stem that moves up and down &#; this ensures the flow of media inside the valve.  They also feature a seat that is structured parallel to the flow. Based on the position of the seat, stem, and disc, one can find different types of globe valves.

There are three main types of globe valves &#; the standard or T-type globe valve, the angle globe valve, and the Y-pattern globe valve. Let us see what are the structural differences between each type of globe valve.

T-Type Globe Valve

T-type is one of the most commonly found types of globe valves, and in it, the seat is placed horizontally &#; this means that the stem and disc travel perpendicular to the seat. This design of a standard globe valve is preferred often because it exhibits the lowest coefficient of flow along with the highest pressure drop.

This globe valve variant is a good option in cases where the pressure drop is not a problem. They are perfect for high-throttling services because of their design.

Angle Globe Valve

These valves are a slight variation of the standard T-type globe valve. Here the ends of the valve are at a 90° &#; this allows the fluid inside the valve to flow in a single perpendicular turn. Compared to Y-pattern globe valves, these valves possess a slightly lesser coefficient of flow.

These valves are capable of handling the slugging effect, thus they are often used in places where the flow is pulsating.

Y-Pattern Globe Valve

Given that globe valves are usually found with a high-pressure drop condition, these Y-pattern or Wye pattern globe valves act as alternatives. The seat and stem, usually found perpendicular to each other, are built at an angle of 45°. These valves can be kept open for a long time without the fear of corrosion.

When in the open position, the angle of this valve offers a straighter pathway for the flow of media. This valve also offers the least resistance during flow.

Parts of a Globe Valve

Like any other industrial valve, a globe valve features three main parts &#; disc, seat, and stem.

• Disc

Again, there are three types of discs when it comes to globe valves &#; conventional disc (ball disc), composition disc, and plug type disc. 

Built earliest, the ball-type disc is made of metal in a ball shape and is fitted against the flat seat of the valve body. A globe valve with a ball disc should be conventionally used for low-pressure situations where intense throttling is not expected.

In the composition disc, a non-metal ring is used on the disc &#; this is done so that tighter closure can be obtained. The valves with composition discs are capable of tight sealing but they do not damage the valve in itself. Commonly used in steam and related applications, these discs are resistant to erosion.

As for plug-type discs, it is the best option for applications that demand high throttling. Long and tapered, these discs are available in many shapes and the surface of the discs is not affected by foreign material easily. 

• Seat 

The seat of a globe valve can either be integrated into the body or can be screwed in. some globe valves also feature a backseat inside the bonnet of the valve &#; this acts as a seal between the seat and bonnet and consequently prevents the building of pressure,

• Stem

The disc and the stem inside the valve are connected in two ways &#; either the T-slot or the disc nut construction.

How Does a Globe Valve Work?

To understand the working of a globe valve, one should understand how the disc and seat of the valve are positioned. The disc inside the valve is movable whereas the seat is stationary and is in a spherical body. The seat is parallel to the pipe and perpendicular to the disc. 

The disc of the valve will move up and down according to the actuation of the wheel on the top of the valve. The wheel can be moved either manually or through an actuator &#; when it is moved, the disc rises and falls as it is attached to the valve stem. To stop the flow completely, mpletely, the disc is fully seated on the seat ring. To resume flow, the disc is lifted up.

Throttling and controlling of flow can be done by adjusting the position of the disc as per need.

If the case is so that the globe valve is operated in low-temperature situations, then the valve is installed in such a way that the pressure falls under the disc. For high-temperature situations, like boilers that work in steam, the valves are positioned to handle pressure above the disc.

What is a Globe Valve Used for?

• Shut-off Capability &#; Globe valves are mainly used for their excellent shut-off capabilities. The discs present in globe valves ensure tight sealing properties, making them a perfect choice as oil valves.
• Throttling &#; Surprisingly, globe valves also make a good choice for throttling and regulating flow. The wheel of a globe valve enables the user to adjust the disc as per need and achieve the right amount of throttling easily.
• Pressure Relief &#; In some cases of special construction, globe valves can be used as pressure relief valves and check valves.

Contact the Best China Valves Manufacturers Today

Globe valves are widely employed in many industries such as oil and gas, cooling systems, boilers, and many others. If you are looking forward to choosing the right type of industrial globe valves for your project, then DomBor is the perfect choice for you. As one of China&#;s leading valve manufacturers, we specialize in a variety of globe valves. Contact us today and get a quote for your project to know more!

Globe valves are operated with a handwheel and modulate water flow. But they also cause higher pressure loss.

Picking the right valve is important, as different types have different features and uses. Some of them only have two states: open or closed. Others allow fluid flow and pressure to be modulated. Distinct valves also cause different amounts of pressure loss. Depending on the situation, specific features are needed.

If you are looking for more details, kindly visit angle bellows globe valve.

One of the most common types of valves is the globe valve. In this article, we explain how globe valves work, including their advantages and disadvantages. Then, we look at the different shapes of globe valves and compare them to other types of devices, like gate valves and ball valves.

QRFS stocks a wide range of valves, including globe valves. Shop T-shaped globed valves and angle valves now.

What is a globe valve, and how does it work?

To decide if a globe valve is right for your application, consider its three core features. First, they are lateral movement valves, which means they open or close based on the up-and-down movement of a stem. Second, they allow, stop, or throttle fluid flow. Some valves have only open and closed states, but globe valves can throttle flow without totally stopping it. Third, they cause significant head losses compared to other valves, a tradeoff for the throttling services.

How globe valves work

From the outside, globe valves have three parts, a handwheel, a bonnet, and a body. The bonnet houses a stem, and when the handwheel is turned, the stem screws up and down in the bonnet. The end of the stem has a small component called a disk or plug, which can be metallic or non-metallic and may come in different shapes, depending on the need.

The globe-shaped body for which the valve is named houses a seat. The seat is a metal frame that divides the body into two chambers and has a hole to allow fluid to pass. When the valve is open, fluid flows up through the opening in the seat. To close it, the stem is screwed down until the disk blocks the seat&#;s opening.

One of the main advantages of globe valves is their ability to throttle or modulate flow. Besides being closed or open, they can also be partially open. This allows you to adjust flow without totally stopping it.

The main disadvantage of globe valves is the comparatively significant head loss they create. Head loss, also called pressure loss, refers to the amount of resistance a liquid encounters as it flows through pipes. The more resistance, the more pressure that is lost. Gravity, friction (of the fluid against the walls of the pipe), and turbulence all cause this loss. Valves and fittings cause pressure loss mainly through turbulence.

Globe valves force fluid to change directions as it passes through, creating loss and turbulence. The exact amount of loss depends on factors like fluid velocity and friction factor. However, it&#;s still possible to review the pressure losses from different valves using a metric called the L/D coefficient.

A valve&#;s L/D coefficient lets us compare it to a straight section of pipe with the same friction factor. L and D stand for length and diameter, respectively. A valve with L/D=5 creates the same friction loss (all else being equal) as a section of pipe with a length-to-diameter ratio of 5. The larger L/D is for a component, the higher the head loss it creates.

A standard globe valve has an L/D=340, compared to an L/D=30 for a 90-degree pipe elbow.

Globe valve shapes

Globe valves come in three shapes&#;t-pattern/z-pattern, y-pattern, and angle pattern. Each form stops or throttles fluid flow in the same way, but the path of flow&#;and thus the head loss&#;differs.

Most globe valves are t-shaped globe or z-shaped. They are called &#;t-pattern&#; for the profile of the valve&#;the inlet and outlet of these valves are in a straight line. &#;Z-shaped&#; is arguably more descriptive, however, because it refers to the path of the water as it flows through the valve rather than the device&#;s external shape. In the standard z-shaped globe valve, the water changes direction twice in a pattern that resembles the letter Z. As mentioned, standard Z-shaped valves cause the most significant head loss, with an L/D=340.

Y-pattern globe valves are modifications of z-pattern valves. The inlet and outlet are still in a straight line, but the bonnet and stem are placed at an angle to the body (as opposed to perpendicular), forming a y-shaped profile. This provides a straighter path for the water than the z-shape, reducing head loss. For y-pattern globe valves, L/D=55.

The inlet and outlet of angle valves are oriented at 90 degrees from one another, and these devices serve both as elbows and valves. Because they only make fluid change direction once, they create less head loss than z-shaped valves, with L/D=150.

When to use globe valves

Globe valves are ideal whenever you need to modulate flow, but you don&#;t have to worry about the amount of pressure loss. Some applications include:

• Cooling water systems
• Fuel oil systems
• Feedwater and chemical feed systems
• Turbine lubricating oil systems
• Drain and trim applications in fire sprinkler or other water-based fire protection systems

Globe valves aren&#;t the best choice for control valve applications in fire sprinkler systems, where pressure is at a premium. Instead, butterfly valves are commonly used.

Globe valve vs. gate valve

There are several alternatives to the globe valve, and understanding the different options can help you pick the right valve for the job. Two major alternatives to the globe valve are the gate valve and the ball valve. First, let&#;s consider the differences between globe and gate valves.

Gate valves, like globe valves, are linear-motion valves. They are opened and closed by turning a handwheel that screws a stem in and out of the bonnet. When a gate valve is closed, an obstruction is pushed down by the stem perpendicular to the path of the fluid.

Unlike globe valves, gate valves don&#;t require fluid to change directions&#;the flow path is straight. As such, gate valves cause very little head loss (L/D=8). However, they do not throttle as well as globe valves&#;fluid flow rate in a gate valve is not proportional to how open the valve is at any moment.

Globe valve vs. ball valve

Unlike globe valves and gate valves, ball valves are rotary-motion valves. This means that ball valves open and close when the obstacle rotates rather than opening and closing with the lateral movement of an obstruction. Specifically, a ball-shaped component with a hole through it spins in its housing, either stopping the fluid or letting it pass.

Instead of turning a handwheel, a ball valve is typically opened or closed with a wrench handle. Only a quarter-turn (90 degrees) is needed to open or close it&#;much faster than turning a handwheel multiple times. Quick closing can actually be a problem because of water hammer. When fluid flowing through a pipe is suddenly stopped, its momentum has nowhere to go because water is non-compressible. Water hammer occurs when a pressure wave propagates back through the pipe, potentially causing damage.

Since ball valves don&#;t force water to change direction, they create very little head loss (L/D=3). As with gate valves, this low pressure loss comes with the tradeoff of little throttling capability. Ball valves are either open or closed, with little in-between.

Globe valves adjust flow, but be careful of the pressure application

When building a piping system, it&#;s important to choose the right components for the job, which is especially true with valves. Because globe valves force water to change directions even when fully open, they create comparatively large pressure losses. One of the core advantages of globe valves, however, is their ability to modulate water flow. They can be open, partially open, or closed.

Gate valves and ball valves, two alternatives to globe valves, cause minimal pressure losses. However, they don&#;t provide throttling services like globe valves. For applications where pressure is at a premium, gate or ball valves are better choices than globe valves.

Shop our inventory of standard (z-pattern) globe valves and angle valves. For other options, shop our full selection of valves, including ball valves.  If you don&#;t see the item you need, contact us, and our customer service team will help you out.

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