1. Кіріспе
Check Valve vs Globe Valve represents a fundamental decision in fluid system design, as both valves are widely used but serve distinct purposes.
While a check valve provides automatic protection against reverse flow, a globe valve is designed for precise flow control and reliable shutoff.
Choosing the appropriate valve impacts system efficiency, қауіпсіздік, energy consumption, and maintenance requirements.
This article presents an authoritative comparison of check valve vs globe valve, exploring their working principles, types, Материалдық таңдау, advantages and disadvantages, және практикалық қосымшалар.
2. What is a Check Valve
А Клапанды тексеріңіз, also referred to as a Кері клапан, is a passive, one-way flow control device designed to allow fluid to move in a predetermined direction while automatically preventing backflow.
Unlike actively actuated valves, a check valve requires no external power, operating purely on fluid dynamics, gravity, or spring-assisted forces.
This simplicity makes it a critical component in protecting pumps, Компрессорлар, and other sensitive equipment from reverse-flow damage, and in maintaining system stability across industrial processes.
The design and performance of check valves are standardized in guidelines such as Апи 594, which covers flanged, lug, wafer, and butt-welding check valves, ensuring consistency and reliability across different applications.
Primary Functions
Check valves perform several critical functions that directly impact system safety, әсерлілік, және сенімділік:
- Backflow Prevention: Protects upstream equipment, such as pumps and compressors, from damage caused by reverse flow, including pump impeller reversal and cavitation.
- Contamination Control: Prevents mixing of process streams—for example, treated water inadvertently mixing with raw water in water treatment plants.
- Pressure Maintenance: Maintains system pressure by blocking reverse flow that could cause pressure drops, surges, or system instability.
Жұмыс принципі
The operation of a check valve is automatically driven by pressure differentials:
- Forward Flow: Upstream pressure pushes the valve’s closure element (диск, plug, or ball) away from its seat, overcoming gravity or spring resistance, allowing fluid to pass through.
- Reverse Flow: When upstream pressure falls below downstream pressure, the closure element is forced against the seat, forming a tight seal to prevent backflow.
Крекинг қысымы, the minimum upstream pressure required to open the valve, is a critical design parameter. Мысалы:
- Swing check valves: 1–5 psi, ideal for low-pressure, high-flow systems.
- Spring-assisted lift check valves: 5–15 psi, suitable for high-pressure or surge-prone pipelines.
Types of Check Valve
| Басу | Design Features | Performance Highlights | Типтік қосымшалар |
| Іздеуді тексеру клапаны | Hinged disc swings open; gravity-assisted closure | Cv ≈ 250 (2-дюймно); ΔP <1 psi @ 100 gpm; cycle life: 100k–500k | Water distribution, Hvac, Төмен қысымды жүйелер |
| Көтерімді тексеру клапаны | Axial disc lifts vertically; tight shutoff | Cv ≈ 200 (2-дюймно); ΔP <3 psi @ 100 gpm; ANSI Class 300–4500 | Жоғары қысымды құбырлар, майлау & газ, boiler feedwater |
| Wafer / Dual-Plate Check Valve | Compact sandwich design; fits between flanges | Cv ≈ 220 (2-дюймно); 50% weight reduction; 70% smaller footprint | Space-constrained chemical, теңіз, or industrial systems |
| Spring-Loaded Check Valve | Spring-assisted closure; reduces slamming | Cv ≈ 180 (2-дюймно); cracking pressure 5–15 psi; cycle life 50k–200k | Vertical pipelines, pump discharge, surge-sensitive systems |
Material Selection for Check Valves
Selecting appropriate materials for check valves is critical to ensure durability, Коррозияға төзімділік, erosion resistance, and operational reliability under varying pressures, температуралар, and fluid chemistries.
| Component | Жалпы материалдар | Температура диапазоны (° °) | Fluid Compatibility | Selection Considerations |
| Body | Көміртекті болат (ASTM A105), 316Л тот баспайтын болат (ASTM A351), Дуфлекс 2205 (ASTM A890) | -29 қарай 425, -269 қарай 815, -40 қарай 315 | Steam, майлау, water, Химиялық заттар, seawater | Carbon steel for general service; 316L for corrosive media; Дуфлекс 2205 for high-strength and offshore applications |
| Closure Element (Диск / Plug / Flap) | Көміртекті болат + Жұлдыз 6, 316L SS, PTFE-coated 316L | Up to 815 (Жұлдыз), дейін 815 (316Өшпін), дейін 260 (Ptfe) | Abrasive slurries, corrosive fluids, sanitary applications | Hardfacing (Жұлдыз) for erosion; PTFE for food, Фармацевтикалық, and low-temperature fluids |
| Көктем | 302 Тот баспайтын болат, Inconel X-750 | -200 қарай 315 (302 SS), -269 қарай 650 (Inconel X-750) | Суару, ауа, бу, газ турбиналары | Material chosen to maintain elasticity under operating temperature and pressure; high-temperature service requires Inconel |
| Орын / Seal | Металл (Жұлдыз, Тот баспайтын болат), Soft (Ptfe, Elastomers) | -200 қарай 450 | High-temperature fluids, corrosive media, sanitary service | Soft seats for tight shutoff and low-pressure applications; metal seats for high-temperature or abrasive fluids |
Артықшылықтары
- Passive, Reliable Operation: No external power required; MTBF typically 5–10 years.
- Low Pressure Drop: Most designs maintain ΔP <3 пси, reducing pumping energy and operational costs.
- Compact and Cost-Effective: Wafer and dual-plate designs save space and installation time; initial cost significantly lower than globe valves.
- Simplified Maintenance: Few moving parts enable quick inspection and overhaul (1–2 hours versus 4–6 hours for globe valves).
Disadvantages
- No Flow Regulation: Cannot modulate flow; only suitable for on/off service.
- Flow-Direction Sensitive: Improper installation can lead to immediate failure.
- Water Hammer Risk: Fast-closing swing checks may generate noise >100 dB and accelerate seat/disc wear.
- Turbulence Sensitivity: Requires straight upstream pipe length (5–10 diameters) to avoid flutter and premature wear.
Applications of Check Valves
Check valves are widely used in systems where backflow prevention, қауіпсіздік, and pressure maintenance сыни:
- Water Treatment: Prevents treated water from flowing back into raw water tanks, ensuring process safety and compliance with EPA standards.
- Майлау & Газ: Lift check valves block hydrocarbon backflow at wellheads and pipelines, reducing risk of fires or explosions (Апи 521 compliant).
- Электр қуатын өндіру: Spring-loaded check valves in boiler feedwater and condensate return lines prevent reverse flow and pump cavitation, maintaining efficiency >99%.
- Фармацевтикалық & Sanitary Processes: Wafer or dual-plate check valves (316Өшпін, electropolished) prevent cross-contamination in sterile or API lines.
- Hvac & Water Distribution: Swing check valves ensure unidirectional flow in pumps, cooling systems, and municipal water networks.
3. What is a Globe Valve
А globe valve is a linear-motion valve designed primarily for flow regulation and positive shutoff.
Its internal construction typically includes a movable disc or plug and a stationary орын,
allowing precise control of fluid flow through the valve body.
Unlike check valves, globe valves require manual or actuated operation, providing operators with the ability to modulate flow rate or fully isolate sections of a piping system.
Globe valves are widely referenced in standards such as Апи 602 (for steel globe valves) жіне Asme b16.34, ensuring uniform performance in industrial applications.
Primary Functions
Globe valves are engineered for precision, serving three key process roles:
- Flow Throttling: Maintains flow rates within tight tolerances (±1–2%) for processes requiring stability (E.Г., chemical dosing, turbine steam supply).
- Pressure Regulation: Reduces high inlet pressure to a lower, stable outlet pressure (E.Г., 1,000 psi to 100 psi for downstream equipment protection).
- On/Off Isolation: Provides tight shutoff (Исо 5208 Class VI for soft-seated designs) for hazardous or valuable fluids (E.Г., toxic chemicals, high-purity pharmaceuticals).
Globe Valve Working Principle
It operates via active, linear stem movement, controlled by an actuator:
- Full Open: The actuator retracts the stem, pulling the disc away from the seat.
Fluid flows through the valve’s internal channel (Z-, Y-, or angle-shaped), with maximum flow achieved when the disc is fully retracted. - Throttling: The actuator partially extends the stem, positioning the disc midway between open and closed.
The gap between disc and seat dictates flow rate—smaller gaps reduce flow and increase pressure drop (a deliberate design feature for regulation). - Full Closed: The actuator fully extends the stem, pressing the disc firmly against the seat.
Metal-seated designs achieve ISO 5208 Class IV leakage (<0.01 cm³/min), while soft-seated designs reach Class VI (<0.0001 cm³/min).
Types of Globe Valve
Globe valves are categorized based on flow path geometry, stem orientation, and functional requirements, allowing engineers to select the optimal design for specific pressure, ағу, and installation constraints.
| Басу | Design Features | Key Performance Metrics | Типтік қосымшалар |
| Straight-Through Globe Valve | Standard globe valve with S-shaped flow path; stem vertical | Cv ≈ 20–150 (2-дюймно); ΔP up to 30 пси | General throttling and isolation in water, бу, and chemical pipelines |
| Бұрыш глобус клапаны | Flow enters one side and exits at 90°; single-baffle design | Cv ≈ 18–140 (2-дюймно); Турбуленттіліктің төмендеуі, easier drainage | Systems requiring directional change, such as chemical or steam lines |
| Y-Type Globe Valve | Stem and disc mounted at an angle (typically 45°) to the seat; straight-through flow | Cv ≈ 25–160 (2-дюймно); ΔP reduced 20–30% vs. straight globe | High-pressure or erosive media; minimizes flow resistance and energy loss |
| Stop-Check Globe Valve | Combines globe and check functionality; can act as manual shutoff or automatic backflow prevention | Cv ≈ 20–120 (2-дюймно); adjustable cracking pressure | Pump discharge lines and critical process systems requiring both isolation and backflow protection |
| Balanced Plug Globe Valve | Disc or plug designed to balance hydraulic forces, reducing stem thrust | Cv ≈ 30–200 (2-дюймно); suitable for high-pressure differential | High-pressure steam, chemical injection, and large-diameter piping where actuation torque is critical |
| Expanding Seat Globe Valve | Seat expands or moves to improve sealing under pressure | Tight shutoff Class VI (Исо 5208) | Applications demanding zero leakage, E.Г., high-purity chemical and pharmaceutical lines |
Material Selection for Globe Valves
Material selection is a critical aspect of globe valve design, as it directly affects Коррозияға төзімділік, erosion resistance, temperature tolerance, Механикалық беріктік, және ұзақ мерзімді сенімділік.
| Component | Жалпы материалдар | Температура диапазоны (° °) | Fluid Compatibility | Selection Considerations |
| Body / Bonnet | Көміртекті болат (ASTM A216 WCB), 316 SS (ASTM A351), Қорытпа 20, Дуфлекс 2205 | -29 қарай 425, -269 қарай 815, -40 қарай 315 | Steam, water, майлау, қышқылдар, Химиялық заттар | Carbon steel for general service; stainless steel for corrosion; duplex/alloy 20 for aggressive chemicals |
| Диск / Plug | 316 SS, Stellite 6-coated carbon steel, Моник, Гастеля | Up to 815 | Abrasive slurries, corrosive or high-temperature fluids | Жұлдыз 6 for erosion resistance; Monel/Hastelloy for highly corrosive media |
| Сабақ | 17-4 PH SS, 410 SS, Inconel X-750 | -200 қарай 650 | High-cycle operation, бу, chemical fluids | High-strength, low-galling material; critical for actuated valves |
| Орын / Seal | Ptfe, Graphite, Flexible Graphite, Metal-to-Metal | -200 қарай 450 | Steam, Химиялық заттар, high-purity fluids | Soft seats (Ptfe, графигі) for tight shutoff at low temperatures; metal seats for high-temperature and abrasive media |
| Packing / Gaskets | Ptfe, Flexible Graphite, Spiral Wound | -200 қарай 450 | Steam, химиялық, high-temperature fluids | Choice depends on temperature, қысым, and media; ensures leak-tight operation |
Артықшылықтары
- Precise Flow Control: Offers excellent throttling capability with predictable characteristics.
- Reliable Shutoff: Can achieve tight closure (metal-to-metal or soft-seated), suitable for isolation and maintenance.
- Flexible Actuation: Compatible with manual, electric, pneumatic, or hydraulic actuators.
- Durable for High Pressure / Температура: Robust construction supports extreme conditions in industrial applications.
Disadvantages
- Higher Pressure Drop: Flow path geometry causes lower Cv and higher ΔP compared to straight-through valves, increasing pumping energy.
- Larger and Heavier: Globe valves are bulkier and heavier than comparable check valves, increasing installation space and structural support requirements.
- Manual / Actuation Required: Cannot operate automatically like check valves; requires operator or actuator intervention.
- Higher Initial Cost: More components, өңдеу, and materials make globe valves 50–70% more expensive than similar-size check valves.
Applications of Globe Valves
Globe valves are widely used in systems requiring precise flow control, reliable shutoff, and pressure management:
- Chemical & Petrochemical: Throttling and metering of corrosive or reactive fluids; soft-seated or alloy-trimmed designs for aggressive media.
- Steam & Thermal Systems: Boiler feedwater, steam distribution, және жылу алмастырғыштар;
Y-type or balanced plug designs reduce actuation torque in high-pressure steam. - Электр қуатын өндіру: Feedwater, cooling water, and auxiliary steam control; ensures tight shutoff and pump protection.
- Суару & Wastewater: Flow regulation, chemical dosing, and directional piping (angle globes) with minimal leakage.
- Фармацевтикалық & Ас: Sterile or high-purity lines; 316L stainless steel, electropolished, soft-seated for CIP and cross-contamination prevention.
- Майлау & Газ: Pipeline injection, compressor discharge, and high-pressure hydrocarbon lines; stop-check variants combine flow control and backflow prevention.
4. Comprehensive Comparison: Check Valve vs Globe Valve
Selecting the appropriate valve type is crucial for system efficiency, сенімділік, and lifecycle cost.
Check valve vs globe valve serve distinct functions and are optimized for different operational requirements. The following comparison highlights their key differences:
| Белгі / Аспект | Клапанды тексеріңіз | Глобус клапаны | Analysis / Implications |
| Негізгі функция | Automatic backflow prevention | Flow regulation and shutoff | Check valves operate passively, while globe valves provide manual or actuated control |
| Operation Type | Passive, automatic | Manual or actuated | Check valves require no external power; globe valves need handwheel or actuator |
| Flow Direction | One-way only | Bidirectional flow possible but designed for controlled flow | Check valves cannot throttle; globe valves can modulate flow with precision |
| Flow Control / Throttling | Not possible | Excellent throttling capability (linear or equal-percentage) | Globe valves are preferred in process control applications |
| Қысым төмен (ΔP) | Аласа (әдетте <3 пси) | Higher due to S-shaped flow path | Check valves minimize pumping energy; globe valves increase ΔP, which may require larger pumps |
| Shutoff Performance | Байсалды (metal or soft-seat) | Tight shutoff achievable (Исо 5208 Class VI) | Globe valves offer better isolation, critical for maintenance and hazardous fluids |
| Response to Flow Surges / Water Hammer | Sensitive; swing checks may slam | Less sensitive; can be modulated to prevent surge | Spring-assisted check valves reduce slamming; globe valves allow controlled closure to avoid pressure spikes |
Maintenance Complexity |
Қарапайым; fewer moving parts (2–5 components) | More complex; multiple components (сабақ, диск, орын, packing) | Check valves are faster to inspect and repair; globe valves require longer downtime |
| Installation Considerations | Direction-sensitive; space-efficient (wafer/dual-plate) | Larger footprint; orientation flexible but requires support | Check valves must follow flow markings; globe valves need sufficient clearance for stem operation |
| Material Flexibility | Carbon steel, Тот баспайтын болат, дуфлекс, PTFE-coated | Carbon steel, Тот баспайтын болат, alloys, soft/metal seats | Both can accommodate high-temperature and corrosive fluids, but globe valves often require more precise trim materials for throttling |
| Типтік қосымшалар | Pump discharge, boiler feed, water treatment, сығылған ауа, sanitary lines | Process control, бу, chemical dosing, Фармацевтикалық, high-pressure isolation | Check valves are safety-focused; globe valves are control-focused |
| Құны | Lower initial cost (50–70% less than globe valves) | Higher initial cost due to machining and components | Lifecycle cost depends on function; globe valves may reduce operational losses in controlled processes |
5. Қорытынды
Check valve vs globe valve are complementary, not interchangeable. Қолданыңыз Клапанды тексеріңіз when you need automatic, passive protection against reverse flow (pump protection, non-return service).
Қолданыңыз globe valve when you need to басқару flow or require positive shutoff with good modulation capability.
The correct selection requires attention to hydraulic performance (Cv and ΔP), transient behavior (water-hammer),
media characteristics (erosion, solids, температура), maintainability, and lifecycle cost.
Where systems need both functions, it is common engineering practice to pair a globe valve (for isolation/control) with a check valve (for backflow prevention) downstream or upstream as appropriate.
ЖҚС
Can a check valve be used for flow control (Дроссляция)?
No—check valves are on/off devices that cannot modulate flow.
Attempting to throttle with a check valve causes disc fluttering (кию) and inconsistent flow. Use a globe valve for throttling applications.
Can a globe valve prevent backflow?
Yes—globe valves can be closed to prevent backflow, but they are not designed for this purpose.
Check valves are more reliable (passive, no actuation required) and cost-effective for backflow prevention.
Using a globe valve as a check valve increases energy costs and maintenance needs.
Which valve causes more pressure loss — globe or check?
Generally a globe valve causes more pressure loss (i.e., lower Cv) than a full-bore or axial check valve of the same nominal size.
Exact values depend on valve design and trim; always use manufacturer Cv/ΔP data.
How do I reduce water-hammer from a closing check valve?
Options include specifying a slow-closing or spring-damped check, adding a hydraulic snubber/accumulator, installing surge tanks, or controlling the driving pump shutdown profile.
