What is Globe Valve ? The differences among globe valve vs ball valve vs gate valve

A globe valve is a type of valve used for regulating flow in a pipeline, consisting of a movable disk-type element and a stationary ring seat in a generally spherical body. Globe valves are named for their spherical body shape with the two halves of the body being separated by an internal baffle. This has an opening that forms a seat onto which a movable plug can be screwed in to close (or shut) the valve.

The plug is also called a disc or disk. In globe valves, the plug is connected to a stem which is operated by screw action using a handwheel in manual valves. Typically, automated globe valves use smooth stems rather than threaded and are opened and closed by an actuator assembly.

Globe valves are used for applications where flow needs to be finely tuned and where the valve may need to be opened and closed frequently. They are not recommended for simple on/off operation or for applications that require full, unobstructed flow because the design of the valve inherently offers a resistance to fluid flow due to the change in direction the fluid must take (entering, changing direction to pass through the seat, and then changing direction again to exit the valve).

Globe valves come in various designs to serve different purposes. The primary types of globe valves include:

1. Tee Pattern or Z-body Globe Valve:
   • The simplest and most common type, characterized by a Z-shaped diaphragm that divides the body. The horizontal setting of the seat allows the stem and disk to travel perpendicularly to the horizontal line. This design provides a good shutoff feature but does not offer the least resistance to flow.
2. Angle Globe Valve:
   • In this type, the fluid flow changes direction only once, which reduces the flow resistance offered by the valve. Angle globe valves are used in applications where the flow needs to be changed direction and where the pressure drop through the valve is not a critical concern.
3. Y-Pattern Globe Valve:
   • In a Y-pattern globe valve, the stem and seat are angled at approximately 45 degrees to the pipe axis, which offers a straighter flow path at full opening and offers less resistance to flow. This design is suitable for high-pressure and other critical applications where pressure drop is a concern.
4. Bellows Sealed Globe Valve:
   • This type incorporates a bellows seal in the stem, which eliminates the need for a traditional gland packing. This design is used in applications where leakage of the fluid through the gland packing must be minimized or eliminated, such as in toxic or hazardous fluid services.
5. Needle Valve:
   • A type of globe valve with a small, needle-shaped disk and a matching tapered seat. It allows for precise flow regulation, making it suitable for applications where precise flow control is required, even at low flow rates.
6. Plug or Stopcock Globe Valve:
   • Uses a plug-shaped disc that allows for a better sealing and is used in applications requiring a tight shut-off.

Each type of globe valve has its advantages and is chosen based on the specific requirements of the application, such as the need for flow regulation, the desired level of tightness in the shut-off, the pressure and temperature conditions, and the nature of the fluid being controlled.

The symbol for a globe valve in piping and instrumentation diagrams (P&IDs) and other schematic representations is characterized by a circular shape with two horizontal lines and a diagonal line across the circle. The diagonal line represents the valve stem and disc mechanism that moves perpendicular to the flow, indicating the valve’s ability to regulate or throttle the flow. Here’s a simple representation:

In P&IDs, additional details may be added to the basic symbol to denote specific features or actuation methods of the globe valve, such as manual operation, pneumatic or electric actuation. However, the core symbol with the diagonal line remains the key identifier for a globe valve.

The specification of a globe valve involves several key parameters that define its suitability for specific applications. When specifying a globe valve, consider the following attributes:

1. Size and Connection:
   • Nominal size, typically given in inches or millimeters, indicates the diameter of the pipe to which the valve will be connected. Connection type (flanged, threaded, butt weld, socket weld, etc.) is also specified to ensure proper integration into the piping system.
2. Body Material:
   • The material from which the valve body is made, chosen based on the application’s temperature, pressure, and the nature of the fluid being handled. Common materials include cast iron, stainless steel, carbon steel, bronze, and PVC.
3. Pressure Rating:
   • Indicated by class or PN number, it specifies the maximum pressure the valve can withstand at a certain temperature. Common ratings include ANSI classes such as 150, 300, 600, etc., or PN ratings like PN10, PN16, etc.
4. Temperature Rating:
   • The maximum and minimum temperature limits within which the valve can operate effectively without damage to its components.
5. Flow Coefficient (Cv):
   • A measure of the valve’s efficiency in passing fluid, indicating the volume of water (in US gallons) that can pass through the valve at a 1 psi pressure drop per minute.
6. Trim Material:
   • The material of the internal parts that come into contact with the flow, such as the seat, disc, and stem. The trim material is selected based on resistance to the fluid’s corrosiveness, erosion, and temperature.
7. Actuation:
   • Specifies how the valve is operated, e.g., manually (handwheel or gear), electrically, pneumatically, or hydraulically. The actuation method is chosen based on the required ease of operation, control precision, and application needs.
8. Sealing Type:
   • Type of seal used in the valve, which could be metal-to-metal, elastomer, or other soft seats. This is determined based on the required tightness of the shut-off and the nature of the fluid.
9. End Connection Standards:
   • Standards that the connection ends of the valve comply with, such as ANSI, ASME, DIN, etc., ensuring compatibility with the piping system.
10. Design Standards:
    • The standards that the valve design complies with, such as API 600 (for steel valves), ASME B16.34 (valves flanged, threaded, and welding end), etc.
11. Testing and Inspection Standards:
    • Standards that the valve’s testing and inspection comply with, such as API 598, which covers valve inspection and testing.

When specifying a globe valve, it’s crucial to consider the specific demands of the application, including the fluid properties, operating conditions, and the system’s performance requirements, to ensure optimal performance and longevity of the valve in service.

Selecting the right globe valve for a particular application involves considering several critical factors to ensure the valve meets the operational requirements, performs efficiently, and has a long service life. Here are the main considerations for selecting a globe valve:

1. Service Conditions:
   • Understand the fluid characteristics (e.g., water, oil, gas, chemicals), as well as the operating temperature and pressure. This will influence the choice of body and trim materials to ensure compatibility and durability.
2. Body and Trim Material:
   • Select materials based on the fluid’s corrosiveness, temperature, and pressure. Common body materials include cast iron, carbon steel, stainless steel, and alloys for high-temperature or corrosive applications. Trim materials should be chosen for their resistance to wear, corrosion, and galling.
3. Valve Size and Connection Type:
   • Determine the appropriate valve size based on the flow requirements and the size of the connecting piping. Consider the type of connection needed (flanged, threaded, butt weld, etc.) for the piping system.
4. Pressure Rating:
   • Choose a valve with a pressure rating that exceeds the maximum operating pressure in the system to ensure safe operation. The pressure rating should be compatible with the flanges and other components in the system.
5. Temperature Rating:
   • Ensure the valve’s temperature rating meets or exceeds the maximum and minimum temperatures of the system to avoid damage to the valve components.
6. Flow Control Requirements:
   • If precise flow control is needed, consider a globe valve with a contoured plug or a parabolic disk to achieve better throttling accuracy.
7. Actuation:
   • Decide whether manual operation (handwheel or gear operator) is sufficient or if automated actuation (electric, pneumatic, or hydraulic) is required for remote operation or integration into an automated process control system.
8. Leakage Class:
   • Consider the acceptable level of seat leakage for the application. The American National Standards Institute (ANSI)/FCI 70-2 standard defines leakage classes for control valves. For tighter shutoff requirements, a higher class number (e.g., Class IV, V, or VI) is preferable.
9. Flow Direction and Pressure Drop:
   • Globe valves generally cause a significant pressure drop in the system. If minimizing pressure drop is critical, consider the valve’s flow coefficient (Cv) and possibly select a valve design (such as a Y-pattern or angle pattern) that offers a lower resistance to flow.
10. Maintenance and Repair:
    • Consider the ease of maintenance and availability of replacement parts. Globe valves with a simpler design and more common parts might be easier and more economical to maintain.
11. Standards and Certifications:
    • Ensure the valve meets relevant industry standards (e.g., ASME, API, ANSI) and certifications for the application, such as those required for steam, food and beverage, or oil and gas industries.
12. Cost:
    • While not a technical specification, the cost is always a consideration. Evaluate the total cost of ownership, including initial cost, maintenance, and potential downtime, rather than just the purchase price.

By carefully considering these factors, you can select a globe valve that meets the operational demands, ensures reliability, and offers a long service life within your system.

1. Flow Regulation:
   • Globe valves excel in applications where the flow rate needs to be adjusted or regulated. Their design allows for precise control of flow, making them suitable for processes that require frequent adjustments.
2. Cooling Water Systems:
   • They are commonly used in cooling water systems where it’s necessary to control the flow of water to different parts of a system or equipment to maintain optimal operating temperatures.
3. Fuel Oil Systems:
   • In fuel oil systems, globe valves are used to regulate the supply of fuel to burners, ensuring a consistent and controlled flow that matches the combustion requirements.
4. Boiler Vents and Drains:
   • Globe valves are used as vents and drains for boilers, allowing for controlled venting of gases or draining of fluids while maintaining the ability to shut off completely when required.
5. Steam Services:
   • They are suitable for steam applications, including steam distribution and condensate lines, where it’s crucial to control the flow and pressure of steam to ensure efficiency and safety in operations.
6. Process Control:
   • In chemical and petrochemical industries, globe valves are used in process control applications where precise flow control is critical for maintaining product quality and process efficiency.
7. Heat Exchanger Isolation:
   • Globe valves are used for isolating heat exchangers to control the flow of the heating or cooling medium, allowing for maintenance or inspection of the exchangers without shutting down the entire system.
8. Water Treatment and Distribution:
   • They are used in water treatment plants and distribution systems to regulate the flow and pressure of water through various stages of treatment and distribution.
9. High-Pressure and High-Temperature Applications:
   • The robust design of globe valves makes them suitable for high-pressure and high-temperature applications, such as in power generation, where they can withstand the demanding conditions.
10. Research and Laboratory Applications:
    • In research and laboratory settings, globe valves are used for precise control of gases and liquids in experimental setups and pilot plants.
11. Pharmaceuticals and Food Processing:
    • In the pharmaceutical and food processing industries, globe valves are used to control the flow of various liquids and gases, ensuring precise process conditions for product quality.
12. Marine Applications:
    • Globe valves are used in marine applications, including on ships and offshore platforms, for controlling seawater, hydraulic systems, and fuel systems.

In each of these applications, the selection of the globe valve is based on the specific requirements, including the nature of the fluid, operating pressures and temperatures, required flow control accuracy, and other operational considerations.

There are numerous manufacturers around the world that produce globe valves, catering to various industrial, commercial, and specialty applications. Some well-known manufacturers include:

1. Emerson (Fisher Valves):
   • Emerson is a global technology and engineering company providing innovative solutions for customers in industrial, commercial, and residential markets. Fisher Valves, a part of Emerson, is renowned for its control valves, including globe valves used in process control industries.
2. Flowserve:
   • Flowserve is a leading manufacturer and aftermarket service provider of flow control systems. They offer a wide range of globe valves suited for various applications, known for their reliability and performance.
3. Crane Co.:
   • Crane Co. manufactures industrial products, including a variety of valves through its Crane Valve Group. They offer globe valves for various applications, known for their durability and quality.
4. KSB:
   • KSB is a leading supplier of pumps, valves, and related systems. Their globe valves are used in a wide range of applications, from basic water applications to complex industrial processes.
5. Velan:
   • Velan is one of the world’s leading manufacturers of steel gate, globe, and check valves for industrial applications. They are known for their high-quality products used in various industries, including power generation, oil and gas, and chemicals.
6. Samson:
   • Samson is a global leader in the manufacture of control valves for industrial processes. They offer a range of globe valves designed for precise control and reliability in various applications.
7. Spirax Sarco:
   • Specializing in steam and thermal energy solutions, Spirax Sarco offers a range of globe valves that are widely used in steam applications, providing efficient and sustainable solutions.
8. Weir Group:
   • The Weir Group creates innovative engineering solutions for the minerals, oil & gas, and power markets. They offer globe valves that are robust and designed for high-performance in demanding conditions.
9. Leser GmbH & Co. KG:
   • Leser is a leading manufacturer of safety valves, but they also offer a range of globe valves for various applications, especially in the chemical and petrochemical industries.
10. Armstrong International:
    • Armstrong provides intelligent system solutions that improve utility performance, lower energy consumption, and reduce environmental emissions. Their globe valves are used in steam, condensate, and hot water systems.

When selecting a globe valve manufacturer, it’s essential to consider factors such as the application requirements, the manufacturer’s reputation, the quality and reliability of their products, their service and support network, and their ability to provide customized solutions if required.

Several international standards apply to globe valves to ensure their reliability, safety, and performance in various applications. These standards cover aspects such as design, testing, materials, and dimensions. Some of the key standards include:

1. API (American Petroleum Institute) Standards:
   • API 600: Covers steel gate valves, but its material and design principles can also be applicable to globe valves in the petroleum and natural gas industries.
   • API 602: Specifies the requirements for compact steel gate valves, globe valves, and check valves for sizes DN 100 (NPS 4) and smaller for the petroleum and natural gas industries.
   • API 598: Valve Inspection and Testing – specifies the testing and inspection requirements for gate, globe, check, ball, plug, and butterfly valves.
2. ASME (American Society of Mechanical Engineers) Standards:
   • ASME B16.34: Valves – Flanged, Threaded, and Welding End – establishes requirements for forged and cast materials of steel, nickel alloy, and other materials used for flanged, threaded, and welding end valves, including globe valves.
   • ASME B16.10: Face-to-Face and End-to-End Dimensions of Valves – provides the valve dimension specifications necessary for installation, which includes globe valves.
3. BS (British Standards) EN Standards:
   • BS EN 13709: Industrial Valves – Steel Globe and Globe Stop and Check Valves – specifies the requirements for globe and globe stop and check valves made of steel for the petroleum, petrochemical, and allied industries.
4. ISO (International Organization for Standardization) Standards:
   • ISO 15761: Steel Gate, Globe and Check Valves for Sizes DN 100 and Smaller, for the Petroleum and Natural Gas Industries – specifies requirements for a series of compact steel gate, globe, and check valves for petroleum and natural gas industry applications.
5. MSS (Manufacturers Standardization Society) Standards:
   • MSS SP-80: Bronze Gate, Globe, Angle, and Check Valves – provides standards for bronze valves, including globe types, for general service.
   • MSS SP-85: Gray Iron Globe & Angle Valves, Flanged and Threaded Ends – covers the requirements for gray iron globe and angle valves.
6. DIN (Deutsches Institut für Normung – German Institute for Standardization) Standards:
   • DIN standards, like DIN EN 13709 (which is harmonized with BS EN 13709), cover the requirements for steel globe valves in various industries.

These standards ensure that globe valves meet specific requirements for design, manufacturing, performance, and testing, providing a level of assurance regarding their quality and reliability in service. When specifying or purchasing globe valves, it’s important to reference these standards to ensure that the valves are suitable for the intended application and meet the necessary regulatory and safety requirements.

Globe valves and gate valves are both commonly used for controlling the flow in piping systems, but they have different designs, operating mechanisms, and are suited for different applications. Here’s a comparison between the two:

Globe Valves:

• Design and Operation:
  • Globe valves have a spherical body with a movable disk or plug and a stationary ring seat. The disk moves perpendicularly to the seat, allowing for flow regulation. The flow path through a globe valve changes direction, which increases resistance and causes a pressure drop.
• Flow Control:
  • They are excellent for throttling and regulating flow because the disc can partially close, offering precise flow control.
• Pressure Drop:
  • Due to their design, globe valves inherently have a higher pressure drop compared to gate valves.
• Shut-off Capability:
  • Provide good sealing and shut-off capabilities but may not be as effective as gate valves for absolute zero leakage.
• Applications:
  • Suited for applications where flow needs to be regulated or throttled, such as in cooling systems, fuel oil systems, and steam services.

Gate Valves:

• Design and Operation:
  • Gate valves have a flat gate or wedge that slides vertically in and out of the flow path, providing a clear opening when fully open. The design is simpler, with a straight-through flow path that minimally obstructs the flow.
• Flow Control:
  • Primarily used for on/off control rather than flow regulation. When partially open, gate valves can suffer from vibration and wear due to the fluid flow.
• Pressure Drop:
  • Typically, gate valves have a lower pressure drop when fully open, as the flow path is straight and unrestricted.
• Shut-off Capability:
  • Excellent for providing a tight seal and minimal leakage when fully closed, making them ideal for applications requiring a secure shut-off.
• Applications:
  • Ideal for applications where a straight flow and minimal restriction are desired, such as in pipelines, water distribution, and where the valve will remain either fully open or fully closed.

Key Differences:

• Purpose: Globe valves are best for regulating flow, while gate valves are preferred for on/off control without flow restriction.
• Design: Globe valves have a more complex design that changes the flow direction, while gate valves offer a straight-through flow path.
• Pressure Drop: Globe valves typically cause a higher pressure drop across the valve compared to gate valves.
• Flow Regulation: Globe valves can precisely control flow rates, while gate valves are not suitable for throttling purposes.

Choosing between a globe and gate valve depends on the specific requirements of the application, including the need for flow control, pressure drop considerations, and whether the valve will be used primarily for isolation or throttling.

Below is a table that compares the key features of globe valves and gate valves:

This table outlines the fundamental differences between globe and gate valves, helping in the decision-making process for specific applications based on flow control needs, pressure considerations, and desired operation characteristics.

Globe valves and ball valves

Globe Valves:

• Design: Characterized by a spherical body with a movable disk or plug and a stationary ring seat. The disk moves perpendicularly to the seat to start, stop, or throttle the flow. The flow path in a globe valve changes direction, which can cause a significant pressure drop.
• Operation: Operated by turning a handwheel or actuator, which moves the disk toward or away from the seat to regulate flow.
• Flow Control: Excellent for throttling and precise control of flow due to the ability to partially open or close the valve.
• Pressure Drop: Generally higher than in ball valves due to the tortuous path the fluid must take through the valve.
• Sealing: Provides good sealing capabilities but may not be as tight as a ball valve in some applications.
• Applications: Commonly used in applications where flow needs to be regulated, such as in cooling systems, fuel oil systems, and steam services.

Ball Valves:

• Design: Features a ball with a hole through its center and a quarter-turn rotational motion to open or close the flow path. When the valve is open, the hole in the ball aligns with the flow path, allowing fluid to pass through.
• Operation: Operated by a lever or actuator that rotates the ball a quarter turn (90 degrees) from fully open to fully closed. This quick, quarter-turn operation makes ball valves suitable for emergency and frequent operation.
• Flow Control: While ball valves can be used for throttling, they are primarily designed for on/off control and may not offer the same level of precise flow regulation as globe valves.
• Pressure Drop: Typically lower than globe valves when fully open, as the flow path through the ball is straight and allows for nearly unrestricted flow.
• Sealing: Excellent sealing capabilities, especially in full-bore designs, where the valve diameter is the same as the pipe, minimizing flow resistance and providing a tight shut-off.
• Applications: Widely used for applications requiring a secure and rapid shut-off, such as in gas pipelines, chemical storage, and residential water systems.

Key Differences:

• Purpose: Globe valves are optimized for regulating flow with precision, while ball valves are best suited for quick and secure on/off control.
• Flow Path: Globe valves have a complex flow path that changes direction, leading to a higher pressure drop, whereas ball valves have a straight flow path when open, resulting in lower pressure drops.
• Operation: Globe valves use a linear motion to move a disk towards or away from a seat, while ball valves use a quarter-turn rotary motion to control flow.
• Sealing and Flow Control: Ball valves generally provide a tighter seal and are more suitable for applications requiring full flow with minimal resistance, but globe valves offer superior throttling capabilities.

The choice between a globe valve and a ball valve depends on the specific requirements of the application, including the need for flow control, desired sealing capabilities, pressure drop considerations, and the frequency of operation.

Here’s a comparative overview:

This table helps in understanding the fundamental differences between globe valves and ball valves, guiding the selection process based on the specific needs of an application, such as the required flow control, pressure considerations, and operational requirements.