Globe Control Valve -FAQ 

A globe control valve is the type of control valve with a sphere-shaped body used to regulate the pipeline’s flow rate. The globe control valve consists of a movable plug and a stationary ring seat. It has the material of bronze or stainless steel structure.

Before you purchase the globe control valve for your application, it is better to understand its basics. This guide will cover the applications, specifications, principles of operation, benefits, and other vital components of the globe control valve.

1. What is a globe control valve?

The globe control valve is suitable in applications with the requirement of throttling of the commodity. You can rotate the valve to achieve the desired level of commodity flows. There is a disc and the seat opening that varies with the proportion of the disc movement. Thus, there is a proportional relationship between the valve opening and disc movement, which regulates the flow rate altogether.

The globe control valve is commonly used for throttling and controlling the flow rate and is suitable for small piping. The sphere-shaped body of the globe control valve has a baffle that separates two valves. The globe control valve’s structure is designed so that it causes resistance in liquid lines and pressure drops.

2. What are the important considerations of the globe control valve?

The globe control valve is used in various piping systems to handle the flow. It acts as an isolation valve and regulates the flow of fluid in the open position. The gate valves, on the other hand, are suitable for fully open or fully closed positions. When using the globe control valve for on-off isolation service, you should be careful in design selection because it is difficult to maintain a tight seal against the vital force that pushes up the disc.

The globe control valve has an easy tear and is easier to repair. It has short-term fluctuations between open and closed positions.

3. What is the working principle of the globe control valve?

The primary function of the globe control valve is to stop, start, and regulate flow. The structure consists of a movable disk and ring seat. The seat of the glob control e valve is in the middle of the pipe, the opening in the seat is closed with the disk. Once the handle is turned, manually or through an actuator, the valve stem lowers or raises the disc.

The fluid flow closes, the disc lowers. When the disc is raised, the fluid flow increases to the maximum rate; when the disc is not submitted to less than the top level, the fluid flow changes with the vertical travel of the disc.

4. What is the difference between the globe control valve and the control valve?

A control valve is equipment that controls the fluid flow by changing the size of the flow passage. It is a power-operated device that regulates the flow of fluids, such as oil, water, and steam.  It is the most common control element used in various industries. A control valve consists of two components, the valve, and the actuator. A control valve can be divided into a globe control valve, angle control valve, and rotary control valve from the structure difference.

A globe control valve is the type of control valve that manages the flow rate and speed of the fluid in the system. It consists of pneumatic actuators that control signals and respond to them by opening and closing the valve. It consists of a pneumatic actuator and a globe valve. It belongs to one type of control valve.

5. What are the models of globe control valves?

Single-seat globe control valve

The single-seat globe control valve consists of a pneumatic actuator and a low flow resistance sleeve and has a simple structure, low noise, and accurate assembling characteristics. The material of the valve core is SS 304 and Stellite. The valve stem and valve body have the material of SS 304.

Double seat globe control valve

The double seat globe control valve offers high flow capacity and is ideal for low-pressure applications. If you want to use them for high-pressure drops, you need to fit them with high-friction trim. It offers high flow control rangeability and can withstand high pipe stresses.

Three-way globe control valve

A three-way globe control valve uses two flows and diverts one flow into two outlets. It controls the circulation of water, oil, and other fluids. The valve size varies from 15 to 300mm. The body material is made of stainless steel, Monel, Alloy 20, and Aluminum bronze.

6. What are the designs of the globe control valve?

There are three basic designs of globe control valve:

• Conventional disc
• Composition disc
• Plug type disc
• 

Conventional Disc

The conventional disc, or the ball disc, is made of a ball-shaped metal disc. The short taper of the disc fits against the flat surface seat, and the design is cheap and popular and can throttle flow. The primary purpose of the conventional disc is to start and stop the flow. It has low maintenance and is easily reground.

Composition Disc

The structure of the composition disc has a complex and non-metallic ring which creates tighter closure. It is erosion resistant and capable of closing on the solid particles without any damage to the valve. There are various types of composition discs available for different services. They are easily repairable and need less power.

Plug Type Disc

The plug-type disc is the best globe control valve design. It has metal plug seating that produces wide seating. It is not affected by foreign matter and provides full flow when the valve is open. This valve has the benefit of easy replacement and repair in case of any damage.

7. What are the advantages of the globe control valve?

A globe control valve is an effective tool for throttling flow control. The flow pattern of the globe control valve changes in direction that result in a high-pressure drop and high resistance to flow. The globe control valve is effective to use in high-pressure operations. Following are the advantages of the globe control valve:

• The globe control valve is made of high-quality material that makes the long product life of the valve.
• It has a good shutoff capability and provides good throttling capability.
• The globe control valve is available in tee and angle patterns, and each offers unique capabilities.
• You can use the globe control valve as a stop check valve.
• The fast opening and closing of the stem are reliable for accurate flow regulation.
• The structure of the globe control valve is simple, and it is easy to maintain.
• The low sealing between sealing surfaces makes a long service life.

8. What are the disadvantages of the globe control valve?

Some of the disadvantages of the globe control valve are as follows:

• As compared to the gate valve, the globe control valve has a high-pressure drop.
• It needs greater force or actuator to seat the valve.
• It has high flow resistance with large opening and closing power.
• The globe control valve is not suitable for the medium with high viscosity and easy coking.
• Despite the more straightforward structure of the valve, it provides poor regulation performance.

9. What are the applications of the globe control valve?

The globe control valve is used widely in various engineering applications. In these types of applications, it is essential to know the flow characteristic inside the valve.

The globe control valve can observe the flow and estimate the performance of the valve.

The most common applications of globe control valves are cooling water systems, fuel oil systems, turbine oil systems, chemical feed systems, main steam vents, drains, and others. In the cooling water system, the globe control valve regulates the flow.

The globe control valve plays an integral part in applications where leak tightness and safety are the primary considerations. It is also used commonly in heater drains, turbine seals and drains, extraction drain systems, etc.

10. What is the stem configuration of the globe control valve?

The control valve stem has the design of the disc, which is rotated to lower or raise the disc. The disc is an essential part of the globe control valve stem that causes the disc to rotate. The stem configurations of the disc are:

• Rotating stem with integral disc
• Rotating stem with non-integral disc
• Non-rotating stem with integral disc
• Non-rotating stem with non-integral disc

The globe control valve has a simple design that incorporates a rotating stem. The disc is an essential component of the stem. When the disc rotates, it results in intense wear of the seat. In rotating stems, the structure of the disc swivels freely to the stem. The discs have a maximum axial play to avoid rapid axial movement of the disc.

There should be a slight connection between the stem and disc to avoid landing on the seat. When it comes to non-rotating stems, the disc is an integral part of the stem and is suitable in high-pressure valves.

11. What are the specifications of the globe control valve?

The globe control valve is an effective tool that provides excellent sealing capability, offers great fluid resistance, and has an S-shaped fluid passage. The nominal diameter of the globe control valve varies according to the materials used. For cast steel, the diameter ranges from 65 mm and above. For forged steel, the nominal diameter is 50 mm and above.

The globe control valve has the body material of ASTM, cast steel, forged steel, carbon steel, stainless steel, etc., and can measure fluid such as water, steam, oil, and gas. The pressure class of the globe control valve varies from class 150-2500 with 400mm. The standardized class varies from class 3500-4500 with 150mm.

The operation method of the globe control valve is manual, pneumatic, and electric. The valve has internal or external threads for inlet and outlet connection. You can start the globe control valve by using an electric actuator.

12. What are the technical requirements of the globe control valve?

All the valves and actuators in the globe control valve should be designed in compliance with the ASME requirements. The material of the valve, the body, bonnet, and body joint bolting should comply with the ASME specifications, and the valve must have a product life of 20 years. The design life does not include the packing, gaskets, and lubrication materials.

The valve dimensions are end-to-end or face-to-face. The valves must be designed to ensure the dimensional requirements. The structure of the valve body should be anti-corrosive and anti-erosion to prevent any erogenous materials inside the globe control valve.

It is not helpful to use threaded bonnet designs. Instead, the cover plates should be secured with a penetration weld. The double-seated structures of the globe control valve can trap fluid and provides pressure relief. This pressure relief prevents any excessive pressure build-ups.

13. What are the actuator and valve installation considerations in the globe control valve?

The valves must prevent stem leakage into the environment. The valve stem should be designed in a way to avoid stem removal from the valve. The actuator should be stiff to maintain the valve stem position. The actuators in the globe control valve should have a manual override for opening and closing the valve in case of any electric power failure. The manual mechanism is also essential for safety reasons.

The actuator gearing should be of metallic construction. The wiring of the actuator housing should be in the main enclosure for environmental protection. The motor and other electric elements should be protected from dust, debris, and moisture. The shaft material should be non-corrosive and fastened in a way to avoid any misalignment.

14. What are the material specifications of the globe control valve?

Some materials are prohibited while designing the globe control valve. Mercury, for instance, should not be allowed in the construction of the valve as it will cause the exposure of valve parts to the metal. Lead or other low melting metals should not be in direct contact with the working fluid. It would be best if you took sufficient measures to prevent contamination of valve material by oil or other lubricants.

The halogen products and use of materials asbestos are also prohibited. In addition, the materials used in the making of the valve are subject to test for chemical and physical properties. The hardness test is of the rubber parts in the valve to ensure it complies with the standards.

15. What are the parts of the globe control valve?

The globe control valve uses a linear motion to start, stop, and regulate flow using a disc. The disc is an essential part of the globe control valve that closes or removes the flow path entirely. As a result, globe control valves have become a more popular and widely used tool for throttling and controlling fluid flow. They are applicable for pipes of size 8 inches or lesser.

A typical globe control valve consists of the valve body, bonnet, disc, stem, yoke, back seat, flange, seat ring, handwheel or actuator, pressure seal gasket, and packing. The seat and disc are essential parts of the globe control valve where a screwed stem controls the seating globe of the control valve.

16. What are the types of globe control valves based on body bonnet connection?

• Depending on the body bonnet connection, the globe control valve is divided into the following categories.
• A screwed bonnet that has a simple structure and design and is inexpensive.
• Bolted bonnet is the most popularly used type of globe control valve. It has a gasket for joint body sealing.
• The welded bonnet is suitable in applications where there is a requirement for disassembly. It has a lighter weight and a simple structure.
• A flanged bonnet is designed for any operating pressure. But when the pressure rises drastically, the flanged bonnet globe control valve becomes heavy.
• Union-ring bonnet is smaller in size. This is because it has the union ring that holds the bonnet to the valve body, and its construction is 3 inches in size.

17. What is the difference between the globe control valve and gate valve?

The globe control valve and gate valve are the most common valves applicable in industrial plants. Both have the structure that works efficiently and accurately. However, these two valves are not the same. They have somewhat similar bodies but offer different features and applications.

Globe control valve is suitable for applications, such as the oil and gas industry. On the other hand, gate valves are also used in the gas and oil industry, but gate valves are only responsible for starting and stopping the flow within the piping system and cannot regulate flow. The globe valve is unidirectional, while the gate valve is a multi-directional valve.

The globe control valve has a spherical body and disc, which moves up and down the seat, and the vertical movement allows the space between seat and disc to change, which provides good throttling capability. In addition, the gate valves have gate faces instead of the disc designed with a rising or non-rising stem.

18. What is the construction of the globe control valve?

The globe control valve is commonly used to open or close a flow in a system and to throttle valves. It consists of rising stems, and the other components are similar to the gate valve. The maintenance of the globe control valve is relatively easy because you can quickly refurbish or replace the discs or seats. In areas where frequent valve maintenance is required, the globe control valve is a suitable solution.

The variation of the globe control valve is different from other valves in terms of varying discs. The plug-type disc has a wide surface with an extended configuration and is anti-corrosive. On the other hand, the composition disc has a flat face that is pressed against the seat. Therefore, it is not suitable for high differential pressure throttling.

The steel globe control valve can handle temperatures up to 750°C. The stainless steel material provides resistance to galling, and corrosion and the seating surface ensures complete bearing contact. For lower pressure applications, you can align it with the extended disc. For higher pressure, the disc turns on a stem to avoid galling of the disc.

19. What are the types of globe control valves?

Pneumatic globe control valve

The pneumatic globe control valves are made of SS316 and are applicable in a wide range of industries. They are designed to handle various process parameters in oil and gas, chemical, petrochemical, pharmaceutical, sugar, and other process industries. It has a pressure rating from 150 to 2500.

Electric globe control valve

The electric globe control valve is popular in its usages because of its unique design, features, and excellent performance. It regulates the flow control by positioning the valve plug to change the aperture between the seat and the plug. In addition, it has a 4-20 MA output signal transmitter and corrosion-resistant actuator. Therefore, it is applicable in chemical processing, irrigation, mining, food processing, etc.

Diaphragm globe control valve

The diaphragm globe control valve is suitable for pressure control and flow control. It has a corrosion-resistant structure and provides accurate positioning.

20. What is the difference between the globe control valve and rotary control valve?

Although there are some similarities between the globe control valve and rotary valve, both of them are different. The physical size of the globe control valve is more significant than the rotary valve. The smaller size of the rotary valve makes it more compact, which saves space and weight.

The sealing life of the rotary valve is longer with fewer fugitive emissions. On the other hand, if you use bellow sealing in the globe control valve, the sealing life becomes shorter. The rangeability of flow range is more significant with rotary valves with less permanent pressure loss than globes. Globe control valves can be expensive in large-scale applications than the rotary valve.

The rotary control valve is actuated in a rotary motion and is applicable in hydraulic-based applications.

Conclusion

The globe control valve is an innovative addition in the world of control valves. It is the most common control valve applicable in various chemical, petrochemical, mining, and food processing industries.

At Instruthink, we offer the latest and advanced globe control valves that provide excellent features and performance at reasonable rates. You can visit the Instruthinkwebsite to know our wide range of globe control valve models. Our technical team will surely assist you in finding a suitable globe control valve for your application.