We at SIO both manufacture and customize top-quality globe valves. These valves are a linear mechanism that is mainly used to start, regulate, and stop fluid flow. The globe disk can close the entire flow or can be completely removed. It will move in a perpendicular manner to the seat during the opening and shutting of globe valves.
This motion will create the annular gap between the seat ring and the disk that will slowly shut as the valve closes. This feature allows globe valves to have excellent throttling capacity that is needed to regulate the flow. There is a lesser chance of leakage because of the right contact between the seat ring and the disk. The angle they are positioned enables a tighter seal between them.
At SIO, you can rely that we will make the best globe valves for your fluid flow needs.
A globe valve is a type of linear motion valve used to start, stop, and control media flow. While most valves are named after the shape of their discs, a globe valve earned its name for its spherical body.
The body of a globe valve is made up of two halves that are separated through an internal baffle. The valve body also has an orifice that serves as the seat to which a movable disc is connected to close the globe valve.
Today, many modern globe valves no longer have spherical bodies. However, they are still considered globe valves as they have similar internal mechanism to that of a traditional globe valve.
A typical globe valve may be used for isolation and throttling. This type of valve creates a slightly higher pressure drop than straight-through valves, such as gate valves, ball valves, and plug valves. This means that a globe valve is recommended in applications wherein the pressure drop is not an important factor.
In this valve type, a positive shut-off is achieved when the disc moves against the direction of the flow. The pattern of process flow through this valve includes several changes in direction. This results in a higher resistance to flow causing a high pressure drop.
A globe valve is well-suited for applications that include high-pressure steam. It can also be used in cooling water systems, feed water, fuel oil systems, chemical feed, boiler drains and vents, turbine drains and seals, and more.
It’s essential to cover the essential points before choosing a globe valve for your project. This helps the overall system to run smoothly and safely and for the globe valve to function excellently for a long time. Moreover, it saves you from the expenses that you will be dealing once problems start to occur as a result of purchasing the wrong valve.
Here are the important factors you must take note before making your final decision:
This is one of the most important factors that you must look into when choosing a globe valve. There are two primary standards on the market for valves – ASME (USA) and EN (Europe). Depending on where the plant or facility is, one of these standards is used. You can usually find this information in the technical specifications of an application.
In ASME standards, the indication of pressure class is # (lbs.) and “ (inches) for the size. Meanwhile, the pressure class is indicated in PN while the size is indicated in DN in EN standards. Unfortunately, this is not the case for many valves sold on the market.
Even though it is indicated that the valve has PN 100 and DN 400, it does not necessarily mean it is in accordance with EN standards. Many valves today have mix standards, it is always to check twice and make it clear with the manufacturer.
In most situations, a globe valve is installed in a pipeline where the size is already provided. If this is your case, it’s easy as the size of the globe valve will be similar to the size of the pipeline. However, there are still other factors that will affect your decision in choosing the right valve size:
• The maximum flow rate
• The acceptable pressure drop
In addition, it’s also important to note that in valve types like globe valves and ball valves, they are available in full bore and reduced bore. For you to choose the right valve, make sure to confirm if there is a requirement for maximum acceptable pressure drop.
For instance, if a globe valve is used in a steam system that generates steam to a turbine, requirements for pressure drop are critical for optimum performance of the turbine. Thus, a full bore globe valve is highly recommended. On the other hand, if a valve is used at the tip of the pipeline to drain water, a reduced bore valve is preferred. This is because the pressure drop is not a controlling factor.
Generally, the pressure class of a valve is already provided through the pressure class of the piping system. If this is not the case, the pressure class is the result of the integration of the main body materials, pressure, and temperature.
To determine the proper pressure class for your globe valve, it’s essential to define the design temperature and pressure of the piping system. Be careful not to determine the pressure class according to the operating conditions of the system. There’s a chance that your globe valve might not tolerate when the “worst case scenario” of a system happens.
The materials of the main parts of your globe valve vary on the properties of process media. The engineer who specifies the valve must check the compatibility and resistance of materials with the process media, such as gas, steam, fluid, etc.
Additionally, don’t forget the working conditions as they’re also essential to the material choice of the valve. For example, while stainless steel is a durable material, it is not ideal in a salty working environment. Instead, aluminum bronze is more suitable.
The trim (disc/stem/seat) materials should be compatible with the body materials of the globe valve. The selected materials also depend on the process media, system conditions, maximum allowable leakage, etc.
The widely used end connections for industrial valves are flanged, welded (BW or SW), and screwed (i.e., NPT). Generally, choosing the end connection is based on the design and construction of the entire piping system. Safety, maintenance, and emission factors are also considered.
Here are the common end connections used in some industries:
• Water and wastewater treatment plants – flanged
• Steam power plants – welded
• Gas systems – welded
• Refineries – flanged
When choosing your globe valve, you also need to determine how you want to operate it. Here are the ways on how to actuate your globe valve:
• Manual (hand wheel/lever)
• Pneumatic actuator
• Electric actuator
While globe valves are mainly used to control flow, they come in a variety of types that differ in materials, actuation, design, etc. This is why it can be confusing to choose which specific type is ideal for your application. To help you, discussed below are the different types of globe valves that will give you a clear idea on what type of globe valve will give you optimal results:
A stainless steel globe valve is often used in cryogenic applications. However, it is also well-suited for services handling high-pressure and high-temperature. Stainless steel is a strong material that has high tolerance to corrosion, abrasion, and certain types of chemicals. This allows the globe valve to function at full performance and helps extend the service life of the valve.
Due to its durability, a stainless steel globe valve is used for corrosive substances, heavy liquids, slurries, oil, gas, and other heavy fluids. It is commonly found in oil and gas industries, water and wastewater treatment facilities, and chemical and petrochemical industries.
A bronze globe valve is a type of globe valve with durability and excellent malleability. This means the valve will not crack easily, which is a problem of several materials. A bronze globe valve is also cost-efficient and has a high resistance to corrosion.
Thus, a bronze globe valve is often used to control flow direction and provide a positive shut-off in applications that deal with high pressure, high temperature, and corrosive materials.
A bronze globe valve is used in both commercial and industrial applications. It is commonly found in HVAC (Heating, Ventilation, and Air Conditioning), compressed air, cold and hot water, gas systems, and other utility services.
A brass globe valve is made from an alloy of zinc and copper, giving the valve increased versatility. Similar to bronze, brass is a malleable material, making it easy to cast or forge. It has excellent corrosion resistance; however, it does not work well when in contact with high chlorine levels.
A brass globe valve is generally more expensive than a bronze globe valve. However, it works better in natural gas lines and other severe applications. It has a high melting point, which makes it suitable for high-pressure and high-temperature applications.
A cast iron globe valve is made of cast iron, an alloy of iron, carbon, and some silicone. It has excellent tolerance to temperature, with some cast iron valves capable of regulating media flows with temperatures more than 1150C (2100F).
A cast iron globe valve is really strong that it typically remains unharmed even after being exposed to frequent vibrations. However, it does not have excellent ductility. Since it is less expensive than a ductile iron globe valve, it is commonly used in various industrial applications that handle low pressure.
Source: Global Sources
A ductile iron globe valve is made from ductile iron, an alloy of iron made with a certain graphite. This makes the globe valve highly ductile, preventing it from breaking easily. It is capable of handling temperatures reaching 730C (1350F).
A ductile iron globe valve has excellent corrosion resistance, yield strength, and tensile strength. These features make this type of globe valve well-fitted for severe working conditions. It is more expensive than a cast iron globe valve, but it has better structure integrity. It can handle high pressures and high temperatures and does not rust easily.
A ductile iron globe valve is commonly used in oil refineries, steam power plants, water and wastewater treatment facilities, and other demanding industrial applications.
A forged steel globe valve is a type of globe valve made from forging steel. The first step of this process uses thermal energy to solidify pieces of steel. The next step is using mechanical pressures to transform steel into the desired configuration of the globe valve. This method allows a forged steel globe valve to have increased strength.
Aside from its durability, a forged steel globe valve is capable of handling temperatures between -196C to 700C, which makes it suitable for high-pressure and high-temperature applications. These include, but not limited to, nuclear power plants, coal-fired power plants, petrochemical systems, pharmaceuticals, general utility services, and hydrocarbon processing.
A cast steel globe valve is made through the process of casting. This manufacturing method melts steel and molds it to the desired form. This method is ideal when customization is needed to meet the specific requirements of a globe valve. This means a cast steel globe valve can be made in specific shapes and can have different parts.
Casting steel allows the globe valve to have enhanced strength, wear-resistance, and a longer lifespan. Because of these features, a cast steel globe valve is used in power generation plants, water, and wastewater treatment plants, chemical and petrochemical facilities, and other industries that handle severe working conditions.
An angle globe valve directs the process flow by 90 degrees without the use of an elbow and extra pipe weld. This allows the disc to open adjacent to the process flow. This design is also used in fluctuating flow conditions as it can handle slugging effects.
A y-pattern or wye globe valve has a stem and seat angled at about 45 degrees to the axis of the pipeline. It provides the least flow resistance. This design is often used in high-pressure and severe applications where pressure drop is an essential factor.
Source: Piping Engineering
Source: Saba Dejlah Tech
A tee pattern / z-type is the most commonly used type in globe valves. It has a simple design wherein the z barrier inside the body contains the valve seat. The horizontal design of the seat allows the disc and stem to move perpendicularly to the pipe axis.
The seat is readily accessible through the bonnet, which is connected to a large orifice above the valve body. The stem passes through the bonnet, similar to a gate valve.
This design makes installation, repair, and maintenance simple. A z-type globe valve is commonly used in applications that require throttling and where pressure drop is not an issue.
A steam globe valve is often used in various industries as it provides accurate control and throttling services. Steam is an essential medium to provide heat to chemical and industrial processes. It is also used to build heat, control pressure and temperature, provide mechanical energy, and remove impurities.
Once the steam is transmitted from the boiler to the application point, it heats through direct heating by coming into contact with the substance to be heated or indirect heating by using a heat exchanger. A globe valve plays an important role in regulating the steam flow from the boiler to the application point. It is used to control water vapor and the pressure level of steam.
Steam applications are commonly found in chemical plants, refineries, and food processing plants.
A cryogenic globe valve is specifically designed to handle applications that involve extremely low temperatures. It is also used where there is high pressure and corrosive media.
A cryogenic globe valve is made with a self-aligning disc and integral seat to ensure a positive shut-off. This also helps extend the lifespan of the globe valve. It is also equipped with an extended bonnet that greatly decreases thermal conduction between the process media and valve packing.
To withstand severe working conditions, a cryogenic globe valve is made from stainless steel, carbon steel, copper alloy, and other durable materials to ensure the valve works optimally for a long time. A cryogenic globe valve is widely used in steel plants, petrochemical plants, air separation facilities, and other oil and gas applications.
A high-pressure globe valve is usually made from stainless steel, carbon steel, or alloy steel. It can handle pressure levels ranging from Class #150 to #2500. It can also work with temperatures at least 425 degrees. A high-pressure globe valve works well with steam, oil, water, and power generation.
A high-pressure globe valve is widely used for shut-off and throttling services in oil and gas industries, power generation, petrochemical plants, hydrocarbon processing, refining, and other industrial applications with severe working conditions.
A high-temperature globe valve is specifically designed to endure service conditions involving high temperature, low temperature, corrosion, abrasion, and in many cases, high viscosity and vacuum. To endure such severe conditions, this type of globe valve is made from stainless steel, carbon steel, duplex, super duplex, Inconel, and Monel.
A high-temperature globe valve is well-suited for handling, liquids, a combination of liquid and solid, gas, powder, slurry, and other viscous fluids. It is widely used in polymers and plastics, fine chemicals, petrochemicals, cryogenic applications, and nuclear plants.
A manual globe valve uses a handwheel or crank to operate the valve. It allows the operator to position the valve accurately as required. The handwheel is connected to a hammer or stem, both of which permits the valve to be hammered to open or close as needed.
In a manual globe valve, the stem twists the disc to close the globe valve. This mechanism is a bit slower and less smooth compared to an automated valve. However, it promotes easy and precise control of the globe valve.
An electric actuator is an excellent solution for actuating globe valves as it is cost-efficient, produces less noise, and promotes smooth operations.
An electric globe valve uses an electric actuator to operate that converts electricity into mechanical energy. It lets the operator to control the valve manually, semi-automatically, and automatically. In some cases, a limit switch is included to stop the motor in a fully open or fully closed position.
A pneumatic globe valve can be operated semi-automatically or automatically through a pneumatic actuator. A pneumatic actuator uses compressed air to operate the globe valve. It is fast-acting, which makes it ideal for throttling services. Since it uses air, a pneumatic actuator is completely safe to use.
A hydraulic globe valve uses a hydraulic actuator to function. A hydraulic actuator works by converting fluid pressure into mechanical energy. In many cases, a hydraulic actuator is equipped with fail-safe features to open or close the globe valve during an emergency. Hydraulic pressure can be obtained through a hydraulic pressure pump contained in the system.
A two-way globe valve is made up of two ports or opening – an inlet port and outlet port. It is used in many applications that require basic on/off services. It is an important component in various safety systems, as it can stop media flow immediately to a specific area when an emergency occurs.
A two-way globe valve can also be used in flow systems with fluctuating flow, temperature, and pressure. It is also used in some hot and cold applications. The plug and stem are adjustable to ensure that the entire system functions optimally. The efficiency of the system also helps prevent damage to equipment and extends the service life of the globe valve.
Since it promotes system efficiency, a two-way globe valve is used in a variety of industries, including oil and gas industries, power generation, water distribution, wastewater treatment, and chemical and petrochemical industries.
A three-way globe valve has a similar structure with a two-way globe valve with an additional port. The ports are labeled as A, B, and AB. A three-way globe valve is primarily used to divert the media flow or combine fluids from two inlet ports that are carried through to one outlet port.
When used as a diverting valve, a three-way globe valve is equipped with one inlet from the supplying side of the pipe and two outlets leading to the return side of the pipe. Generally, a diverting valve is more expensive compared to a mixing valve.
Source: Instrumentation Tools
When used as a mixing valve, a three-way globe valve is made with two inlet ports from the supplying side of the pipe and one outlet port to the returning pipe. This allows the media flow to be mixed before delivering through an outlet.
A three-way globe valve is often used in process industries that deal with oils, chemicals, and water.
Flanges are one of the most widely used end connections in industrial valves. Using a flanged end allows the globe valve to be installed and removed easily from the pipeline.
To guarantee a positive seal, a gasket is installed between the flanges. This gasket can be metallic, non-metallic or a mixture of both, depending on the nature of the application and the materials used in the pipelines. Flanged ends are used in globe valves with sizes 15 mm and up.
A socket weld globe valve is selected when the ends of the pipelines it is used in are flat or plain. A socket weld end is exclusively used in steel globe valves with sizes 50 mm and lower. It is used in high-pressure and high-temperature applications that do not require regular dismantling.
A threaded globe valve uses screws to connect to pipelines. As a general rule, valves with threaded or screwed ends have female threads, whether parallel or tapered. However, there are special instances wherein a male thread is used instead.
Usually, a threaded end is used in smaller globe valves that are made from bronze. It is sometimes used in steel and iron valves, depending on the application and system requirements.
A butt weld globe valve has end connections beveled to meet the thickness of the wall of the pipeline. In some cases, backing rings or sleeves are used to align the valve bore and pipeline. These rings are also used to prevent weld spatters from going through the pipeline.
Butt weld end connections are mainly used for steel globe valves with sizes 50 mm and up. They are often used for applications that handle high pressure and high temperature.
Source: Spirax Sarco
A single-seated globe valve has a simple design and few interior parts. Because of these, it is easy to access and maintain. It has one seat and one disc and is smaller compared to a double-seated globe valve.
With this configuration, the pressure of process flow pushes against the disc or plug, needing more actuator force to control the movement of the globe valve.
A single-seated globe valve creates excellent shut-off and less vibration. Since it is more commonly used than a double-seated, it is available in various trim designs and can handle a wider range of flow features.
A double-seated globe valve consists of two seats and two plugs that function inside the valve body. It has more interior parts, making it heavier and bigger in size compared to a single-seated. It is an older design, which means it is more common in older systems. It is rarely used in modern applications as the single-seated is more preferred today.
A double-seated globe valve uses opposing pressures from the plugs to decrease the actuator force needed to operate the globe valve. This improves the flow capacity of the valve. However, due to these opposing pressures, a positive shut-off is not guaranteed.
A globe valve with a ball disc is mainly used in low-temperature and low-pressure applications. It is designed to start and stop media flow; however, it also has excellent throttling capabilities.
A globe valve with a needle disc provides better throttling services compared to the other disc types. There are various long and tapered needle discs available to meet different flow requirements.
A globe valve with a composition disc uses a strong insert ring to create a positive shut-off.
A globe valve with a pressure seal bonnet is widely used in high-pressure and high-temperature applications. In a pressure seal design, the bonnet is pulled up and seals against the gasket.
This mechanism provides a seal between the inner diameter (ID) of the body and the pressure seal gasket. This means that when there is a higher force in the gasket, the pressure in the body cavity increases, reducing the chances of leakage.
A screwed bonnet globe valve has the simplest design among the types of bonnet connections. Even with a simple design, a screwed bonnet offers a strong and pressure-tight seal. It is often used when the budget is the main concern.
A welded bonnet globe valve has a body and bonnet welded directly without using any bolts. It is typically used when there is no need for disassembly. A welded bonnet is compact, sturdy, and is lighter compared to a bolted bonnet globe valve.
A bolted bonnet is the most used bonnet connection in globe valves. The body and bonnet flanges are connected using nuts and studs with a gasket (made from compatible materials) attached between the flange faces to help better seating. The nuts or studs are tightened to desired torques in a design determined by the manufacturer to achieve positive sealing.
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