What is a Globe Valve?
Globe valve is an indispensable component in many industries, a mechanical conductor that skillfully directs the flow of fluids. Unlike its gate valve, which operate on an all-or-nothing principle, the globe valve thrives in the realm of modulation. Its internal working consists of a disc, which is compared to a plug or a ball, that oscillates in a direction perpendicular to a fixed valve seat within the valve body. This type of valve enables the gradual closing of the flow path and provides the operator with the means of controlling the flow rate of the liquid or gas passing through the system. From the swirling steam in power plants to the constant flow of oil in refineries and the regulated flow of water in treatment plants, the globe valve is a symbol of engineered control of the lifeblood of industry. This type of valve is very flexible in its application.
Critical Factors to Consider Before Selecting Your Globe Valve
Pressure and Temperature Requirements
It is crucial to understand the operational environment of the globe valve before even thinking about the numerous designs and materials. The pressure and temperature of the system are critical, and they define the operating environment that the valve has to function in effectively and safely. Just as a climber requires equipment that is suitable for the altitude and the climatic conditions of the climb, a globe valve must be also designed to handle the forces and thermal loads that it will encounter in its service. Failure to consider these basic parameters can result in a disaster, which may affect the equipment and people. The selected valve material and its pressure class should be higher than the maximum expected high pressure and the temperature range of the valve components including the seals and packing should be compatible with the entire range of operating temperatures. Therefore, it is important to understand the expected pressure of the fluid.
Media Compatibility
Another important criterion that depends on the fluid flow that will go through the globe valve is the material compatibility. Suppose one is pouring acid into a container made of chalk; the outcome is an obvious sign that the internal parts of the valve must be able to withstand the corrosive or erosive nature of the media. If the wrong material is chosen, it results in corrosion, leakage, and finally, valve failure. For example, if the application involves aggressive chemicals, then the material of construction may be stainless steel or Hastelloy while for water systems, carbon steel or brass may suffice. For fuel oil systems, there are also certain material considerations that are important as well. It is therefore important to understand the chemical and physical characteristics of the media in order to select the most appropriate globe valve that will not corrode easily.
Flow Control Requirements
The major advantage of a globe valve is that it offers excellent control of the flow of the fluid. While the globe valve is not suitable for on/off service, it is ideal for throttling since it can control the velocity and volume of the fluid effectively. However, the general flow control needs of an application will determine the type of valve to be used. Factors such as the desired degree of control, the potential for cavitation (the formation of vapor bubbles in a liquid due to pressure drop), and flashing (the rapid vaporization of a liquid as it passes through the valve) must be considered. There are various types of globe valve designs especially in relation to the valve trim which is the part of the valve that regulates the flow of the fluid. The good throttling ability of a globe valve makes it suitable for precise flow control even when there is possibility of noise due to turbulence. It is therefore important to understand these requirements in order to choose a valve that will not easily wear out or get damaged.
Valve Size and Connection Type
Selecting the size of a globe valve is a crucial factor that depends on the size of the pipeline and the flow rate. If the valve is chosen to be too small, the pressure drop and flow will be high and if the valve is too large, it will be unstable and costly. This decision is usually made by using the desired flow coefficient and the allowable pressure drop across the valve in the calculations to achieve the best valve sizing. Besides size, the type of connection is also crucial for easy connection to the piping system of the building. The main types of connections of globe valves are flanged connections, screwed connections and welded connections. The type of connection depends on the material of the pipe, the conditions under which the pipe will be operating and the maintenance that will be done on the pipe. The coefficient of flow is a critical factor in this decision.
Types of Globe Valve
Based on Structure Design
Straight Pattern Globe Control Valves
The straight pattern globe valve is designed with a simple in-line design where the fluid flows in and out in a horizontal manner. This is because flow regulation is attained by the movement of the valve disc which is connected to the stem in a vertical manner to the valve seat to form an S shape. Although this design is quite general and effective, the two turns the fluid has to make results in a higher pressure drop than in other designs. The direction of flow is usually straight through, so these valves are used in general service applications where accurate control of the flow is not the paramount concern but but reliable regulation is important, for example in water supply systems, steam systems and other industrial processes.
Angle Pattern Globe Control Valves
The angle globe valve has an inlet and outlet port which are perpendicular to each other and thus serves as both a valve and a pipe elbow. It is similar to the straight pattern, but the disc is oriented perpendicular to the flow. One of the major benefits of this design is that it eliminates the need for many pipe fittings, which makes installation easier and may be cheaper. Angle pattern globe valves are most suitable for use in systems where the flow direction has to be changed by 90 degrees as in the case of feed lines to a drum or in the discharge lines of a pump where the valve can be easily operated and serviced.
Y-Pattern Globe Control Valves
The Y-pattern globe valve is characterized by the fact that its stem and bonnet are positioned at approximately 45 degrees to the main flow direction. This design provides a more efficient flow path than the straight pattern and thus has a much lower pressure drop. Operation remains constant, where the disc travels along the inclined stem to regulate the flow against the valve seat. The reduced turbulence and energy loss make Y-pattern globe valves particularly advantageous in high pressure and high-temperature services. They are also used in applications where low pressure drop is desirable for the system such as in some steam and condensate systems.
Based on Actuator Design
Manual Globe Control Valves
Manual globe control valves are the most basic in operation, relying on an operator to turn a handwheel or lever, which in turn raises or lowers the valve stem and disc. These valves are simple in design, cost-effective, and offer reliable flow regulation for applications where remote control or automated adjustments are not necessary. Their advantages lie in their ease of use and maintenance, making them suitable for applications where adjustments are infrequent or where a local, direct control mechanism is sufficient, such as in isolation duties or for making occasional flow adjustments in less critical processes. The required speed of operation is dictated by the manual input.
Pneumatic Globe Control Valves
Pneumatic globe control valves utilize compressed air to actuate the valve. The air pressure drives a piston or diaphragm connected to the valve stem, allowing for rapid and precise positioning of the disc. A key advantage of pneumatic actuators is their speed of response, making these valves ideal for automated control systems where quick adjustments are required based on process variables. They are commonly found in applications requiring frequent throttling or on/off cycling, often integrated with PID controllers in chemical processing plants, refineries, and other automated industrial settings. This is an appropriate method of actuation for many dynamic processes.
Electric Globe Control Valves
Electric globe control valves employ an electric motor to provide the force needed to move the valve stem and disc. These actuators offer accurate and repeatable positioning, making them suitable for applications demanding accurate flow control. Electric actuators can be equipped with various control features, including feedback signals and communication protocols, allowing for sophisticated integration with distributed control systems (DCS) and supervisory control and data acquisition (SCADA) systems. They are often used in water systems, power generation facilities, and other industries where precise, often automated, flow regulation is critical over extended periods, ensuring reliable performance and optimal performance.
Based on Connection Method
Flange-Connected Globe Valve
Of the globe valves, the flanged type is widely used especially when working with large pipeline diameters and high pressure applications. Flange type means that the valve ends are provided with projecting ledges called flanges with drilled holes. These flanges are then fitted and tightened to the corresponding flanges on the pipe ends by the use of bolts and nuts. This method of connection provides a strong and reliable joint that can easily handle the forces exerted by the fluid pressure. Sometimes, to enhance the sealing capability and to avoid leakage, a gasket that may contain a metallic ring is fitted between the two flanges before the bolts are tightened. The metallic insert enhances the mechanical properties of the gasket and makes it more capable of withstanding high pressure and preventing leakage.
Threaded Globe Valve
Threaded globe valves are another type of pipeline connection that is quite distinct from the others; they are characterized by two ends that are threaded. These threaded ends are then directly screwed into the other threaded ends of the connecting pipes. This type of connection is normally used for valves with small nominal sizes and relatively low pressure ratings. The very nature of threaded connections is not very suitable for very large pipes or extremely high pressures because the threaded joint may not offer the required strength or sealing capability under such conditions. They are easy to install and do not need many tools but only basic tools like wrenches to screw the valve into the desired position. This simplicity of installation often translates to lower initial costs compared to flanged or welded connections, especially for smaller systems.
Welded Globe Valve
Welded globe valves are the most secure type of pipeline connection that can be achieved in terms of strength and leakage. In this type of connection, the ends of the globe valve are directly connected to the ends of the connecting pipes by the use of welding. This makes the valve to be permanently fixed and very strong in the pipeline thus making it to be an inseparable part of the pipeline. Therefore, welded connections are the best and most suitable for applications where high pressure and high temperatures are involved and where a permanent and strong connection is necessary to ensure a very tight fit and no possibility of leakage. However, welded connections do have some limitations that should be taken into account. They are generally more expensive than flanged or threaded connections at the initial stage of installation due to the fact that welding is a professional activity that requires professional welders to weld the pipe connections in accordance with the industry standards.
Globe Valves vs. Other Valve Designs: Advantages and Limitations
| Feature | Globe Valve | Ball Valve | Gate Valve | Butterfly Valve |
| Primary Function | Throttling and flow regulation | On/off control, some throttling in specific designs | On/off control | Throttling and flow regulation |
| Flow Restriction | Higher pressure drop due to tortuous flow path | Lower pressure drop when fully open | Very low pressure drop when fully open | Moderate pressure drop |
| Throttling Ability | Excellent, designed for frequent throttling | Limited throttling capability, can cause seat wear when partially open | Poor throttling capability, designed for fully open or fully closed operation | Good throttling capability, especially in larger sizes |
| Cost | Generally more expensive than ball or butterfly valves for the same size | Generally less expensive than globe valves for the same size | Generally less expensive than globe valves for the same size | Generally less expensive than globe valves for larger sizes |
| Applications | High-pressure, high-temperature, frequent operation, precise flow control | On/off service, quick actuation, slurries (depending on design) | On/off service, minimal flow obstruction when fully open | Large diameter, low to medium pressure applications, slurries (depending on design) |
The Evolution of Globe Valve Technology and Future Trends
The history of the globe valve can be dated back to the period of industrial revolution when the need for flow control was realized. The first models were crude and simple, and they were made from materials such as cast iron. As the metallurgical technology improved, new and better materials like different grades of steel alloys were used in the construction of globe valves to handle more and more severe service conditions. Technological advancements that aimed at enhancing sealing, minimizing wear, and increasing the accuracy of control. The advent of pneumatic and electric actuators marked a significant turning point, allowing for remote operation and integration into automated process control systems.
The advancements in globe valve technology that have occurred in the recent past have focused on the improvement of the existing designs and the integration of smart elements. In the case of pneumatic globe valves, there has been improvements in the type of actuator used where they are now more compact, efficient and responsive. Likewise, electric actuators have also experienced advancements in the motor technology, which provides higher accuracy and energy consumption. The digital positioners and communication protocols can be used to provide complex control and diagnostic capabilities. As for the future development of globe valve technology, it is expected that the intelligent and networked globe valve will become the development trend in the future. We can expect further improvement of the materials that can withstand the harshest environments and the integration of sensors and data analysis for maintenance and efficiency.
Vincer Actuated Globe Valves: Engineered for Superior Performance and Reliability
Vincer is a company that specializes in flow control and more specifically in actuated globe valves. Understanding the importance of these valves in different processes, Vincer has designed its electric and pneumatic globe valves to be highly performing and dependable. This is evident in the choice of high quality materials and the fact that they conduct various tests on the products.
Vincer’s electric globe valves are designed for accurate positioning and compatibility with the current control systems. These valves are designed with strong actuators to enable them to perform well in harsh conditions. Likewise, Vincer’s pneumatic globe valves offer quick and smooth operation, which is suitable for applications that need quick action. Their electric and pneumatic actuated globe valves are designed to last long and are not easily affected by wear and tear hence they do not require frequent replacement. Thus, the actuated globe valves by Vincer are a perfect fit for industries that require both high performance and reliability of the flow control equipment.
For more information:
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Email: sales@vincervalve.com
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Phone: +86 13724477011 / +86 13724477011
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Address: No.203, Building 1, No.110, Dayuan Road, Zhangcun, Dongcheng, Dongguan, GuangDong, China
Installation and Maintenance Best Practices for Globe Valve
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Installation: The installation of the globe valve is very crucial in order to have a long and efficient service of the valve. It is important to ensure that the valve meets the required pressure class and is compatible with the process fluid. The pipeline should be free of any debris or foreign material that may harm the valve’s internal parts. Proper positioning of the valve in the pipeline is crucial to avoid pressure being applied to the valve body and the connected piping. Sufficient reinforcement should be offered to avoid pressure or loads that may exert pressure on the valve. It is always advisable to follow the manufacturer’s instructions to the letter when installing the product.
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Maintenance: This is the process of checking on the globe valve and taking measures to prevent it from developing faults in the future. Some of the checks that should be made during the routine checks include checking for any signs of leakage around the bonnet, packing or any joints in the body. Other observations that should be made include signs of wear or corrosion on the valve body and the actuator. It is recommended that the valve stem and actuator parts be lubricated as per the manufacturer’s guidelines to avoid any sticking. The packing which is used to seal the stem may require occasional adjustment or replacement to avoid leakage. Any problem that is noticed in the operation of the valve, for instance, if the valve is hard to open or close or if it does not shut tightly, then troubleshooting measures should be taken to determine the cause of the problem. This is because addressing the problems early will prevent them from worsening and affecting the valve’s durability.
Conclusion
In conclusion, the globe valve remains a valuable and widely used product in many industries where accurate control of the flow of fluids is critical. Due to their good throttling capacity and a fairly close shutoff, they are widely used in power generation, chemical processing, water supply and many other applications. It is important to understand the different various types of globe valves in order to choose the right valve for a particular application. In line with the advancement in flow control, the use of pneumatic and electric actuated globe valves has become a strategic way of improving efficiency and automation in many industries. Therefore, working with a reliable merchant like Vincer is the best decision you can make.