Tipos de válvulas de bola

A globe valve is a linear-motion industrial valve used to start, stop or regulate the flow of liquids, gases and steam. It controls the process by moving a disc or plug toward or away from a stationary seat inside the valve body.

Unlike a gate valve, which is primarily intended for fully open or fully closed isolation, a globe valve can operate effectively at intermediate positions. Its disc-and-seat arrangement provides controlled changes in flow area, making globe valves widely used for throttling, pressure regulation, steam control and frequent operation.

There is no single globe valve design suitable for every application. Globe valves can be classified according to body pattern, flow direction, disc design, seat arrangement, bonnet construction, stem sealing method, actuation and intended service. Each type provides a different balance of pressure drop, control accuracy, shutoff performance, maintenance access and operating force.

This guide explains the main types of globe valves, how they differ and what engineers and purchasers should review when selecting a globe valve for an industrial piping system.

¿Qué es una válvula de bola?

A globe valve contains a valve body, bonnet, stem, disc or plug, seat ring and stem-sealing system. Turning the handwheel or moving an actuator raises or lowers the stem. The stem movement changes the distance between the disc and seat, which changes the available flow area.

When the disc is fully raised, fluid passes through the valve body and seat opening. When the disc moves closer to the seat, the valve restricts the flow and creates a greater pressure drop. When the disc contacts the seat, the valve stops the flow.

The internal path is generally more restrictive than the straight bore of a ball valve or the fully open passage of a gate valve. This creates higher pressure loss, but the controlled restriction is what allows a globe valve to provide stable throttling.

The term “globe” originally referred to the rounded shape of early valve bodies. Modern globe valves may have straight, angled, compact or Y-shaped bodies while still using the same basic linear disc-and-seat operating principle.

1. T-Pattern Globe Valve

The T-pattern globe valve, also called a standard-pattern or conventional globe valve, is the most recognizable globe valve design. Its inlet and outlet connections are located on the same centerline, while the seat is positioned across the internal passage.

Fluid entering the valve changes direction as it moves toward the seat opening and changes direction again before leaving the body. These directional changes create turbulence and a relatively high pressure drop.

The T-pattern design is widely used because it provides effective throttling, reliable shutoff and a practical body shape for many industrial applications. It is commonly installed in steam, condensate, cooling water, fuel, bypass and general process lines.

A T-pattern globe valve is a strong choice where pressure loss is acceptable and controlled flow adjustment is more important than maximum flow efficiency. The conventional body also provides a stable seat arrangement and can accommodate several disc and trim designs.

Typical T-Pattern Applications

T-pattern globe valves are commonly used for steam isolation, equipment bypasses, pump discharge control, boiler auxiliary systems and process lines that require frequent operation. They can be supplied as manual stop valves or as actuated control valves.

2. Y-Pattern Globe Valve

A Y-pattern globe valve positions the stem, disc and seat at an angle to the main pipeline. The body and bonnet form a shape similar to the letter Y.

The inclined arrangement creates a straighter and smoother flow passage than a conventional T-pattern valve. Fluid changes direction less sharply as it passes through the seat, which reduces turbulence and pressure loss.

A Y-pattern globe valve is often selected for high-pressure or high-temperature service where the valve remains fully open for long periods but must still provide reliable isolation. The lower pressure loss helps reduce pumping or compression energy when continuous flow is important.

Y-pattern designs are common in steam, boiler feedwater, power generation and high-pressure process systems. They may be supplied with bolted bonnets, welded bonnets or pressure-seal construction depending on the pressure class and application.

The angled stem requires sufficient installation and maintenance clearance. The valve orientation and actuator arrangement should therefore be reviewed during piping layout.

3. Angle Globe Valve

An angle globe valve has inlet and outlet connections positioned approximately 90 degrees from each other. The valve changes the direction of the pipeline while controlling or isolating the flow.

Because the body performs the function of both a valve and a pipe elbow, an angle globe valve can reduce the number of separate fittings in the piping system. This can simplify layout where the pipe must turn near the control or isolation point.

Angle globe valves are used in boiler blowdown, steam service, drains, condensate systems, pressure-reducing stations and process lines where fluid direction changes through the valve.

In flashing or erosive service, an angle-body control valve may direct the high-velocity outlet flow into a larger or specially protected downstream connection. Selected designs can include hardened trim, outlet liners or expanded outlet sections.

The outlet piping must be supported correctly because the change in flow direction creates reaction forces. The preferred flow direction and valve orientation should follow the manufacturer’s design instructions.

Comparison of Globe Valve Body Patterns

4. Conventional Disc Globe Valve

A conventional disc globe valve uses a relatively flat or slightly tapered disc that moves against the valve seat. The design provides straightforward on-off operation and is commonly found in general utility service.

The seating contact area and material determine shutoff performance. Metal-to-metal seating can withstand higher temperatures, while a resilient sealing element may provide tighter shutoff in compatible lower-temperature service.

Conventional discs are suitable where the valve is used mainly for isolation with occasional flow adjustment. For continuous modulating duty, a contoured plug or purpose-designed control trim usually provides a more predictable flow characteristic.

5. Plug-Type Globe Valve

A plug-type globe valve uses a long, tapered or contoured closure member rather than a flat disc. The plug enters the seat opening as the valve closes.

The plug profile can be designed so that each increment of stem travel creates a controlled change in flow area. This makes plug-type globe valves suitable for throttling and automatic process control.

Control-valve plugs may be designed for linear, equal-percentage or quick-opening flow characteristics. The appropriate characteristic depends on the pressure distribution and response of the complete piping system.

Plug surfaces and seat rings may be hardened for steam, high-pressure water or erosive process fluids. In automatic service, the plug is connected to a pneumatic, electric or hydraulic linear actuator.

6. Needle-Type Globe Valve

A needle valve is a specialized small-bore design related to the globe valve principle. It uses a long, narrow tapered needle that enters a small seat opening.

The gradual needle profile allows very fine changes in flow area. Needle valves are therefore used for instrumentation, pressure gauges, sampling systems, hydraulic equipment and low-flow chemical injection.

Needle valves are intended for relatively small flow rates. They are not normally used as the main control valve in a large industrial pipeline.

When purchasing a needle-type valve, the buyer should confirm pressure rating, stem-tip design, orifice size, end connection and compatibility with the process medium.

7. Soft-Seated Globe Valve

A soft-seated globe valve uses a resilient polymer or elastomer at the disc or seat interface. The softer sealing material can conform to small surface imperfections and provide tight shutoff with moderate closing force.

Soft-seated valves are used in water, air, HVAC and compatible chemical services. Common sealing materials include EPDM, NBR, PTFE and other engineered polymers.

The seat material must be selected for the actual fluid, concentration, pressure and temperature. A material that performs well in water may not be suitable for oil, solvent, steam or high-temperature gas.

The pressure-temperature limit of the complete valve may be lower than the rating of the metal body because the soft seat, packing and body seals can determine the allowable service conditions.

8. Metal-Seated Globe Valve

A metal-seated globe valve uses metallic seating surfaces on the disc or plug and seat ring. Metal seating is selected for steam, high temperatures, abrasive fluids and operating conditions that exceed the capability of resilient materials.

The seating surfaces may use stainless steel, hardened alloy or hard-facing materials to improve resistance to erosion, corrosion and repeated operation.

Metal-seated valves require controlled machining and alignment to achieve reliable shutoff. Their allowable leakage rate should be specified clearly because metal-to-metal seating may be evaluated differently from resilient seating.

In severe throttling service, the disc and seat may be exposed to high velocity, cavitation or wire-drawing erosion. Trim hardness and geometry should therefore be selected from the actual pressure drop and fluid condition.

9. Packed-Stem Globe Valve

A packed-stem globe valve uses compressed packing rings around the valve stem to prevent process fluid from escaping through the bonnet.

The packing is compressed by a gland and gland follower. Correct compression is important: insufficient compression may allow external leakage, while excessive compression increases stem friction and actuator force.

Common packing materials include graphite, PTFE and engineered combinations selected for temperature, chemical compatibility and fugitive-emission requirements.

Packed-stem construction is widely used because the packing can be adjusted or replaced during planned maintenance. Low-emission service may require live-loaded packing, polished stem surfaces and qualification testing.

10. Bellows Seal Globe Valve

A bellows seal globe valve contains a flexible welded metal bellows around the stem. One end of the bellows is attached to the stem, while the other is connected to the bonnet or valve body.

As the stem moves, the bellows expands and contracts without allowing the process fluid to reach the main packing area. This creates an additional pressure boundary and greatly reduces the possibility of routine stem leakage.

Bellows seal globe valves are used for toxic, hazardous, high-purity, radioactive or expensive fluids where external leakage must be minimized. Common applications include chemical processing, vacuum systems, heat-transfer fluids and selected nuclear or pharmaceutical services.

Many designs retain secondary stem packing above the bellows. The packing provides an additional seal if the bellows is damaged and can also prevent outside contamination from entering the bonnet.

Bellows material, cycle life, stroke and pressure-temperature capability must be evaluated carefully. The valve should not be selected only because it is described as bellows sealed.

11. Bolted Bonnet Globe Valve

A bolted bonnet globe valve uses a bolted connection between the valve body and bonnet. A gasket or pressure seal prevents leakage through the joint.

Bolted bonnet construction provides practical access to the disc, seat and stem components during maintenance. It is widely used in cast and forged globe valves across low-, medium- and high-pressure applications.

Bonnet bolting, gasket material and joint design must match the pressure and temperature. Reassembly requires clean sealing surfaces and a controlled bolt-tightening sequence.

For elevated-temperature service, thermal cycling can affect gasket compression and bolt loading. The valve manufacturer’s maintenance procedure should be followed rather than applying a general flange-bolting method.

12. Welded Bonnet Globe Valve

A welded bonnet globe valve joins the bonnet to the body through a welded pressure boundary. This eliminates a conventional bonnet gasket and can reduce the number of external leak paths.

Welded bonnet construction is frequently used in compact forged-steel valves for high-pressure steam, water and process service. It provides a strong and compact assembly where routine internal access is not expected.

Purchasers should understand whether the bonnet is fully welded, seal welded or designed with another manufacturer-specific construction. Maintenance and replacement procedures may differ significantly from a bolted bonnet valve.

13. Pressure Seal Globe Valve

A pressure seal globe valve uses internal system pressure to increase the sealing force at the body-to-bonnet joint. As pressure rises, the pressure-seal gasket is forced more firmly against the sealing surfaces.

This construction is widely used in high-pressure and high-temperature power generation systems, including main steam, boiler feedwater and related services.

Pressure-seal valves are available in T-pattern, Y-pattern and angle-pattern configurations. They may use manual operators, gearboxes or electric, pneumatic and hydraulic actuators.

Correct assembly of the pressure-seal gasket, spacer ring, retaining components and bonnet is essential. Maintenance should be performed by personnel familiar with the specific valve design.

14. Single-Seated Globe Control Valve

A single-seated globe control valve has one plug and one seat ring. The design can provide reliable shutoff and a well-defined flow passage.

Because process pressure acts across the plug area, the actuator must generate enough thrust to move and seat the plug under the maximum differential pressure. The required actuator force can become significant as valve size and pressure drop increase.

Single-seated valves are widely used for steam, gas, liquid and chemical process control. They can be supplied with unbalanced plugs for straightforward shutoff or pressure-balanced plugs to reduce actuator thrust.

15. Double-Seated Globe Control Valve

A double-seated globe control valve uses two plugs and two seat rings arranged so that process forces partially oppose each other. This can reduce the net thrust required from the actuator.

The design has historically been used where large flow capacity and lower actuator force are important. Achieving simultaneous tight contact at both seats can be more difficult than with a single-seat valve, so the required shutoff class must be considered during selection.

Modern balanced single-seat and cage-guided control valves are also widely used to manage actuator force while providing predictable trim performance.

16. Cage-Guided Globe Control Valve

A cage-guided globe valve uses a cylindrical cage or retainer surrounding the plug. The cage guides plug movement, retains the seat ring and can contain specially shaped flow openings.

By changing the size and shape of the cage openings, manufacturers can create different flow characteristics and manage noise, cavitation or high pressure drop.

Cage-guided control valves are used in process plants, power stations, oil and gas facilities and steam systems that require automatic regulation.

The trim can be designed for standard control, low noise, anti-cavitation, multi-stage pressure reduction or dirty-fluid service. The correct design must be selected through control-valve sizing rather than pipe size alone.

17. Balanced and Unbalanced Globe Valves

An unbalanced globe valve plug is exposed to the process pressure difference across a substantial plug area. The actuator must overcome this pressure force as well as packing friction and seating force.

A balanced plug includes internal passages and sealing elements that reduce the effective pressure force acting on the plug. This allows a smaller actuator to control a larger valve or higher differential pressure.

Balanced construction can include piston rings, seals or pilot arrangements. The sealing components must be compatible with the process temperature and fluid.

When comparing control-valve quotations, purchasers should confirm whether the trim is balanced or unbalanced and review the calculated actuator thrust at the maximum differential pressure.

18. Stop Globe Valve

A stop globe valve is primarily intended to isolate the pipeline, although its disc-and-seat arrangement may also permit manual throttling. It is commonly operated with a handwheel or gearbox.

Stop valves are used in steam, water, oil and general utility systems. The disc may be conventional, tapered or plug shaped depending on the shutoff and regulation requirements.

The operator should avoid using excessive handwheel force after the disc contacts the seat. Excessive force can damage the stem, disc, seat or operating threads.

19. Globe Control Valve

A globe control valve is designed to regulate process flow automatically. It combines a globe-style body and control trim with a pneumatic, electric or hydraulic actuator.

A sensor measures flow, pressure, temperature or level, and a controller sends a signal to the actuator. The actuator changes the plug position until the measured process approaches the required setpoint.

Control valves are sized according to flow capacity, pressure drop, fluid properties and required control range. Selecting a control valve only by matching the pipe diameter can produce an oversized valve with unstable low-travel operation.

Control-valve selection should also evaluate cavitation, flashing, choked flow, aerodynamic noise, actuator fail position and required shutoff performance.

20. Stop-Check Globe Valve

A stop-check globe valve combines the functions of a globe isolation valve and a lift check valve. It can be closed manually to isolate the pipeline, while its disc can move automatically to prevent reverse flow when the valve is placed in the operating position.

Stop-check valves are used in boiler, steam and power generation systems where operators require both manual isolation and non-return protection.

The internal design and operating procedure differ from a conventional globe valve. Purchasers should confirm flow direction, disc guidance, manual stem interaction and check-valve performance.

Manual, Electric and Pneumatic Globe Valves

Manual Globe Valve

A manual globe valve uses a handwheel, impact handwheel or gearbox. Manual operation is suitable where valve movement is infrequent and the installation is accessible to operators.

The handwheel rotates the threaded stem mechanism and converts rotary movement into linear disc travel. A position indicator may show whether the valve is open, closed or partially open.

Electric Actuated Globe Valve

An electric globe valve uses a multi-turn or linear electric actuator. It is suitable for remote isolation and control where electrical power is available.

Electric actuators can include local controls, manual override, position indication, torque protection and digital communication. The actuator must be sized for stem thrust, operating time and required duty cycle.

Válvula de globo neumática

A pneumatic globe valve commonly uses a diaphragm or piston actuator. Pneumatic actuation provides fast response and is widely used for automatic process control.

Spring-return actuators can move the valve to a fail-open or fail-closed position if instrument air is lost. A positioner provides accurate intermediate positioning for modulating service.

Globe Valve Materials

Globe valve body materials are selected according to pressure, temperature, process chemistry and external environment.

Cast iron and ductile iron valves are widely used in water, HVAC and moderate-pressure utility service. Carbon steel provides mechanical strength for oil, gas, steam and general process systems.

Stainless steel is selected for many corrosive, sanitary and clean-fluid applications. Alloy steels are used for elevated-temperature steam and power generation. Duplex stainless steel and special alloys may be required for chloride-containing or severe chemical service.

The body material alone does not define compatibility. The disc, seat, stem, packing, gasket and actuator materials must also suit the process conditions.

How to Select the Correct Globe Valve Type

Globe valve selection should begin with the required function. A manually operated isolation valve, a steam throttling valve and an automatic pressure-control valve may all use globe-style bodies, but their trim and actuator requirements are different.

1. Define the valve duty. Determine whether the valve will isolate, throttle, regulate automatically or prevent reverse flow.
2. Identify the process fluid. Confirm chemical composition, solids content, toxicity, corrosiveness and contamination requirements.
3. Confirm pressure and temperature. Include normal, maximum, startup, shutdown and cleaning conditions.
4. Select the body pattern. Choose T-pattern, Y-pattern or angle-pattern construction according to pressure drop and piping layout.
5. Select the trim. Choose the disc, plug, seat, cage and balancing arrangement according to shutoff and control requirements.
6. Select the stem seal. Choose conventional packing, low-emission packing or bellows sealing according to leakage risk.
7. Select the bonnet. Evaluate bolted, welded or pressure-seal construction according to pressure, temperature and maintenance.
8. Select the operator. Choose a handwheel, gearbox, electric actuator or pneumatic actuator based on access and control duty.

Globe Valve Procurement Checklist

Globe Valve Applications

Globe valves are widely used in steam supply and distribution because they can provide gradual opening, effective shutoff and controlled flow adjustment. Y-pattern and pressure-seal valves are common in high-pressure power applications, while conventional T-pattern valves serve general steam and utility lines.

In cooling-water and HVAC systems, soft-seated globe valves regulate heat-exchanger and coil flow. Automatic globe control valves respond to temperature or pressure signals from the plant control system.

Chemical plants use stainless steel, alloy and bellows-sealed globe valves for corrosive, toxic or high-purity media. Material compatibility and external-leakage requirements are particularly important in these applications.

Oil and gas facilities use globe valves for fuel regulation, bypass lines, compressor systems and process control. Hardened trim may be required where pressure reduction creates erosion or high velocity.

Boiler and power generation systems use stop, stop-check, Y-pattern and pressure-seal globe valves in steam, feedwater, drains and vents.

Globe Valve Installation Considerations

Globe valves can be directional. Process pressure acting below or above the disc affects operating force, shutoff and valve stability. The valve should be installed according to the flow arrow and manufacturer’s instructions.

The piping must be clean before installation because weld slag, rust and debris can damage the disc and seat. Pipe supports should prevent excessive loads from acting on the valve body.

Flanged valves require clean, aligned mating flanges and compatible gaskets. Weld-end valves must be protected from excessive heat and welding contamination.

Manual valves need enough space for handwheel operation and stem travel. Actuated valves require clearance for the actuator, maintenance access and removal of the bonnet or trim.

Frequently Asked Questions About Globe Valve Types