Globe Valve vs Gate Valve – Համապարփակ համեմատություն

1. Ներածություն

Globe Valve vs Gate Valve is one of the most common comparisons in industrial fluid control, as both valve types are widely applied in pipelines for isolation and regulation.

While they share the same broad purpose—controlling the flow of liquids, գազեր, or steam—their internal geometries, sealing methods, and operational characteristics differ significantly.

Selecting between the two requires careful evaluation of factors such as flow efficiency, կնքման կատարումը, actuation speed, lifecycle cost, and industry-specific requirements.

A poor choice can increase operating costs, reduce reliability, and compromise safety.

2. Ինչ է գլոբուս փականը?

Էունք գլոբուսային փական is a type of linear-motion valve designed primarily for regulating and throttling flow.

Its name comes from the spherical body shape in early designs, though modern globe valves may also use straight, անկյուն, or Y-pattern configurations.

Unlike gate valves, which are intended for full shut-off, globe valves excel at providing controlled, variable flow with relatively short stroke movement.

Globe valves are commonly used in Գոլորշի համակարգեր, Քիմիական մշակում, Էլեկտրաէներգիայի սերունդ, և ջրի մաքրում—anywhere precise control of pressure or flow is needed.

Աշխատանքային սկզբունք

The operation of a globe valve is based on the vertical movement of a disc (խրոց) against a stationary seat.

• The valve disc is connected to a stem that moves linearly when the handwheel or actuator is turned.
• When the disc is lowered, it presses against the seat, արգելափակում է հոսքը.
• As the disc is raised, flow passes through the space between the disc and the seat, which creates a tortuous S-shaped path.
• The degree of opening directly correlates with the amount of flow, giving globe valves good throttling accuracy.

This geometry introduces higher flow resistance (ճնշման անկում) compared to gate valves but provides superior control precision.

Հիմնական հատկանիշները

• Flow Control Accuracy: Globe valves provide precise regulation, with flow coefficients (Cv) that allow incremental adjustments.
  Օրինակ, a 6-inch globe valve can achieve control accuracy within ±5%.
• Sealing Options: Available with մետաղից մետաղական նստատեղեր for high-temperature service (մինչեւ 650 ° C) կամ soft-seated designs (PTFE, էլաստոմերներ) for bubble-tight shutoff in low-pressure systems.
• Versatile Configurations: Straight pattern (ստանդարտ), անկյունային նախշ (90° flow turn, reduces fittings), and Y-pattern (ավելի ցածր ճնշման անկում).
• Չափի միջակայք & Վարկանիշներ: Typically manufactured from ½ inch to 24 դյույմ, with pressure classes from ANSI դաս 150 մինչև Դաս 2500.
• Տեխնիկական սպասարկում: Disc and seat are relatively easy to access for replacement, which makes globe valves popular in power plants where seat erosion is common.

3. Ինչ է դարպասի փականը?

Էունք դարպասի փական is a linear-motion isolation valve designed to provide on/off control of fluid flow.

Unlike globe valves, which are optimized for throttling, gate valves are intended to be fully open or fully closed.

Their defining feature is a flat or wedge-shaped gate (սկավառակ) that moves perpendicularly into the flow path to stop fluid.

Gate valves are widely used in յուղել & Գազատարներ, municipal water distribution, Էլեկտրաէներգիա, and general process industries where full bore flow and minimal pressure drop are required.

Աշխատանքային սկզբունք

The gate valve operates by raising or lowering a wedge or parallel disc between two seat rings:

• When the handwheel or actuator is turned, the stem moves the gate upwards, withdrawing it completely from the flow path.
  In the fully open position, the bore is unobstructed, allowing flow with negligible resistance.
• When closed, the gate is pressed into the seat, blocking the passage and ensuring isolation.
• Gate valves are not recommended for throttling, as partial opening exposes the gate and seat to high-velocity fluid, causing vibration, քայքայում, and sealing damage.

There are two main disc designs:

• Parallel disc դարպասի փականներ (flat gate between parallel seats).
• Wedge gate valves (solid or flexible wedge providing better seat tightness and misalignment tolerance).

Հիմնական հատկանիշները

• Minimal Flow Resistance: In the fully open position, the straight-through bore yields a pressure drop close to zero (flow coefficient Cv is significantly higher than in globe valves of the same size).
• Bi-directional Service: Gate valves can generally seal against pressure from either direction, making them suitable for isolation in complex piping layouts.
• Չափի միջակայք & Վարկանիշներ: Commonly available from 2 inches up to 60 դյույմ կամ ավելին, with pressure ratings from ANSI դաս 150 դեպի Դասարան 2500, making them a preferred choice for մեծ տրամագծով խողովակաշարեր.
• Slow Operation: Gate valves require multiple turns of the stem to fully open or close, making them less suitable where quick operation is required.
• Կնքման կատարումը: Typically designed to meet API 598 արտահոսքի չափանիշներ, but not usually available in tight shutoff classes (Class VI bubble-tight like globe or ball valves with soft seats).
• Maintenance Considerations: Seat and wedge replacement can be complex due to large body size, and erosion or galling may occur if used improperly for throttling.

4. Դիզայն & Internal Geometry of Globe Valve vs Gate Valve

The most fundamental distinction between գլոբուս փականներ մի քանազոր դարպասի փականներ կայանում է նրանց մեջ internal flow path and disc design, which directly influences pressure drop, կնքումը, and operating suitability.

Globe Valve Design & Երկրաչափություն

• Հոսքի ուղի: In a globe valve, the fluid must change direction—first downward through the seat and then back upward—resulting in a more tortuous flow path.
• Disc/Plug Shape: The closure element is typically a խրոց, սկավառակ, or cone that presses against a seat ring perpendicular to the flow.
• Seat Orientation: Seats are arranged horizontally, making globe valves well-suited for throttling and frequent operation.
• Stem Motion: The stem moves linearly, with relatively short travel compared to gate valves (about 25–30% of bore size).
• Structural Implications: The compact flow chamber creates higher pressure loss but enables finer control of flow.

Gate Valve Design & Երկրաչափություն

• Հոսքի ուղի: The flow passage in a gate valve is ուղիղ միջոցով. When fully open, the gate is entirely out of the flow, offering a near-zero pressure drop.
• Disc/Wedge Shape: The closure element is a wedge or slab gate that lowers between two vertical seats.
• Seat Orientation: The seats are vertical and parallel to the flow path.
• Stem Motion: The stem travel is large—equal to the full bore of the valve (100% of bore size)—making operation slower but ensuring full unobstructed flow.
• Structural Implications: Requires a tall yoke and bonnet due to long stem travel; compactness is sacrificed for low flow resistance.

5. Հոսքի բնութագրերը & Hydraulic Performance

Է հոսքի դինամիկա of a valve determine how effectively it can regulate, շնչափող, or isolate process fluids.

The internal geometry of globe and gate valves creates distinct hydraulic behaviors.

Globe Valve Flow Characteristics

• Գծային / Equal Percentage Flow Control: Globe valves provide a nearly linear or equal-percentage relationship between stem travel and flow rate, making them well-suited for modulating and throttling service.
• Press նշման անկում: Due to the abrupt change in flow direction across the seat, globe valves generate relatively high pressure losses.

• • A 6-inch Class 300 globe valve may exhibit a pressure drop of 2.5–3.5 psi at 100 ժապավեն, compared to less than 1 psi for a gate valve of the same size.

• Cv (Հոսքի գործակից): Lower Cv per valve size (≈30–60% of a gate valve) — limiting maximum flow but enhancing precision in partial open conditions.

Gate Valve Flow Characteristics

• On–Off Behavior: Gate valves are designed for isolation rather than throttling. The wedge gate provides nearly unobstructed flow when fully open.
• Minimal Pressure Drop: With a straight-through bore, the hydraulic resistance is almost equivalent to a piece of pipe of the same size.

• • Օրինակ, a fully open 6-inch gate valve typically has a ճնշման անկում <0.5 psi ժամը 100 ժապավեն.

• Poor Throttling Suitability: Operating a gate valve partially open leads to turbulence, կավիտացիա, and seat/gate erosion.
• Cv արժեքներ: Very high Cv values (≈90–100% of nominal pipe size) make gate valves ideal for systems requiring minimal flow restriction.

6. Կնքման կատարումը & Արտահոսքի դասեր

The ability of a valve to maintain a tight seal is critical for process safety, արտադրանքի որակը, եւ արդյունավետություն.

Globe valve vs gate valve achieve sealing in different ways, which impacts leakage performance and suitability for specific services.

Globe Valve Sealing

• Seat-to-Disc Contact:
  Գլոբուս փականները օգտագործում են ա disc pressing against a seat ring. Because the contact area is small and the sealing force is concentrated, globe valves can achieve high-quality shutoff.
• Արտահոսքի դասեր:

• • Capable of meeting ANSI/FCI 70-2 Class IV or V (industrial tight shutoff).
  • With soft-seated or elastomer inserts, some globe valves can achieve Class vi (պղպջակների ամուր անջատում).

• Երկկողմանի կնքում:
  Most designs are unidirectional (optimized for pressure on the downstream side), but certain designs with double-seat arrangements support bidirectional sealing.
• Շռայլ & Հագնում:
  Since globe valves are often used in throttling service, seat wear over time can lead to increased leakage.
  Hard-facing materials such as Stellite or tungsten carbide coatings are often applied to improve longevity.

Gate Valve Sealing

• Wedge Gate Contact:
  Sealing occurs between the դարբաս (wedge/disc) and the seat rings. Tight shutoff relies on proper wedge alignment and seating force.
• Արտահոսքի դասեր:

• • Typically achieve Class III or IV shutoff in metal-seated versions.
  • Soft-seated or resilient wedge gate valves can reach Class V or VI, but these are less common in high-pressure services.

• Bidirectional Capability:
  Most gate valves are naturally երկկողմանի, capable of sealing against flow in either direction.
• Սահմանափակումներ:
  In partially open positions, flow impinges directly on the sealing surfaces, leading to erosion and Նստատեղի արտահոսք ժամանակի ընթացքում. Այս պատճառով, gate valves are unsuitable for throttling service.

Application Implications

• Globe փականներ are preferred where leak-tight performance and flow modulation էական են, such as steam isolation, condensate control, and chemical feed systems.
• Դարպասի փականներ are favored in on–off isolation service, particularly in pipelines, ջրի բաշխում, եւ յուղ & գազի փոխանցում, որտեղ bidirectional shutoff with minimal leakage բավարար է.

7. Գործառնական արագություն, Ակտիվացում & Ավտոմատ

8. Ճնշում-ջերմաստիճանի հնարավորություն & Նյութական նկատառումներ

Valve selection must account for աշխատանքային ճնշում, ջերմաստիճան, և նյութական համատեղելիությունը, as these factors directly affect safety, ամրություն, և ծառայության ժամկետը.

Globe and gate valves differ in design tolerances and material behavior under P–T extremes.

Ճնշում & Temperature Ratings

Նյութական նկատառումներ

• Գլոբուսային փական:

• • Material selection depends on կոռոզիիոն, քայքայում, եւ հագնել դիմադրություն, particularly for throttling or high-velocity flow.
  • Ընդհանուր համաձուլվածքներ: Ածխածնի պողպատ, չժանգոտվող պողպատ (304/316/316Լակոտ), կրկնակի, Նիկելի համաձուլվածքներ (Հաստելո, Մանգաղ) Ագրեսիվ քիմիական նյութերի համար.
  • Կնիքներ & Նստատեղեր: Metal-to-metal or soft seats (PTFE, գրաֆիտ, էլաստոմերներ) to handle wide P–T ranges.

• Դարպասի փական:

• • Designed primarily for լրիվ ծակոտկեն, low-resistance flow.
  • Նյութեր: Ածխածնի պողպատ, չժանգոտվող պողպատ, բրոնզ, Ալյումինե պողպատ.
  • Նստատեղեր: Metal seats dominate high-pressure, բարձր ջերմաստիճանի ծառայություններ; soft seats used for low-pressure, Ամուր անջատում.

9. Ամրություն & Տեխնիկական սպասարկում

• Գլոբուս փականներ: Wear occurs at seat/disc interface due to throttling, and packing wear at stem. Easier to maintain trim without removing valve body.
• Gate valves: Vulnerable to jamming from solids, seat erosion when throttled, and stem corrosion. Maintenance can require disassembly of bonnet and sometimes body removal.

Ծառայության ժամկետը

• Գլոբուսային փական: 10–20 years in moderate service, shorter in erosive/throttling applications without maintenance.
• Դարպասի փական: 15–25 years for isolation service, but service life reduces drastically under partial opening or high-velocity fluid conditions.

10. Typical Industry Applications of Globe Valve vs Gate Valve

The selection between globe and gate valves depends on flow control requirements, ճնշում, ջերմաստիճան, and operational frequency.

Globe Valve հավելվածներ

Globe valves excel in հոսքի կարգավորում, շռայլ, and frequent operation.

Their design allows precise control of fluid flow and pressure drop, making them suitable for systems where modulation is required.

Հիմնական հավելվածներ:

• Steam Control Systems: Precise flow and pressure regulation in boiler feedwater and heating systems.
• Chemical and Petrochemical Plants: Accurate dosing, throttling corrosive or high-temperature fluids.
• HVAC and District Heating: Modulating valves for temperature and pressure control in large piping networks.
• Ջրի մաքրման կայաններ: Flow control for filtration, Քիմիական ներարկում, and dosing applications.
• Energy and Power Plants: Feedwater regulation, cooling water flow, and turbine bypass systems.

Դարպասի փականների հավելվածներ

Gate valves are primarily used for on/off isolation with minimal pressure drop when fully open.

They are suitable for large-diameter pipelines and applications where flow modulation is not needed.

Հիմնական հավելվածներ:

• Յուղել & Գազատարներ: Mainline isolation, պոմպակայաններ, and crude transport.
• Distribution րի բաշխում & Կեղտաջան: Large-diameter mains and treatment plant isolation valves.
• Էլեկտրաէներգիայի սերունդ: Isolation of cooling water, steam headers, and fuel lines.
• Industrial Process Lines: Non-throttling isolation of chemicals, սեղմված օդը, or gas pipelines.
• Ծովային & Նավաշինություն: Ballast water and fuel isolation systems.

11. Comparative Summary Table – Globe Valve vs Gate Valve

12. Եզրափակում

Երկուսն էլ գլոբուս փականներ vs դարպասի փականներ are indispensable in industrial piping systems, but their roles differ significantly.

Globe valves are the go-to solution for accurate flow regulation and reliable shutoff in high-pressure, բարձր ջերմաստիճան, and process-critical environments.

Gate valves, ի հակադրություն, are more economical and energy-efficient for large-diameter isolation duties where minimal pressure drop is essential.

The correct choice depends on whether the application prioritizes control precision կամ հոսքի արդյունավետությունը.

Engineers and plant designers must weigh lifecycle costs, process needs, and operating conditions to ensure optimal performance and reliability.

 

ՀՏՀ

Can a gate valve be used for throttling?

No—partially open gate valves create turbulence and cavitation, reducing service life by 70% and causing flow instability (±20–30% շեղում).

A refinery using gate valves for throttling experienced 3x more seat failures than plants using globe valves.

What is the maximum temperature for a soft-seated globe valve?

Փափուկ նստած (PTFE) globe valves are limited to ≤260°C. For higher temperatures (260-650°C), use metal-seated globe valves with Stellite 6 զարդարել.

Above 650°C, metal-seated gate valves are preferred (PTFE degrades, and globe valves’ pressure drop becomes inefficient).

Which valve is more cost-effective for an oil pipeline?

Gate valves—their 10-year TCO ($29,000 for 12-inch) է լինել 28% lower than globe valves ($40,000).

Gate valves’ low pressure drop saves $120,000 annually in pump energy costs, offsetting higher upfront downtime costs.

Are gate valves suitable for corrosive fluids like seawater?

Yes—use duplex 2205 or 316L gate valves with metal-to-metal seals.

A marine platform using duplex 2205 gate valves achieved 10-year service life in seawater, with no corrosion (corrosion rate <0.001 մմ / տարի). Avoid soft-seated gate valves (seals degrade in saltwater).