مقدمه مقایسه: شیر دروازه گوه ای و شیر دروازه موازی

دریچه دروازه ای دریچه ای است که دیسک در جهت عمودی در امتداد خط مرکزی مسیر حرکت می کند. شیرهای دروازه ای عمدتاً برای برش در خط لوله استفاده می شوند.

یکی از رایج ترین طبقه بندی ها را می توان به شیرهای دروازه گوه ای و دریچه های دروازه موازی با توجه به پیکربندی سطح آب بندی تقسیم کرد..

شیر دروازه گوه ای را می توان به تقسیم کرد: نوع دیسک تک, نوع دیسک دوبل و نوع دیسک ارتجاعی; شیر دروازه موازی را می توان به نوع تک دیسک و نوع دو دیسک تقسیم کرد.

سطح آب بندی شیر دروازه موازی عمود بر محور لوله است., به این معنا که, دو سطح آب بندی موازی با یکدیگر دریچه ورودی هستند.

سطح آب بندی شیر گیت گوه ای نسبت به محور لوله زاویه دارد, به این معنا که, دو سطح آب بندی به یک شیر دروازه ای گوه ای شکل. اندازه زاویه شیب گوه عمدتاً به دمای محیط بستگی دارد, به طور کلی دمای کار بالاتر است, زاویه گرفته شده باید بزرگتر باشد, به منظور کاهش احتمال گوه شدن دروازه در هنگام تغییر دما.

The design concepts, operating principles, performance characteristics, and suitable applications for these two structures differ significantly. For end-users, a thorough understanding of these differences is key to making informed selection decisions, ensuring system stability, and optimizing procurement costs.

As a globally recognized top-tier valve manufacturer, Farpro YD Valve possesses extensive valve data and information to enlighten our customers on gate valve knowledge. Here, the Farpro YD Team will provide a detailed explanation of the distinctions between parallel gate valves and wedge gate valves, offering valuable insights based on our vast experience. Farpro به تفصیل تفاوت بین شیرهای دروازه موازی و گوه ای را توضیح خواهد داد:

Part One: Gate Valve Fundamentals Recap

Before diving into the comparison, let’s briefly review the basic concepts of gate valves:

1. Operating Principle: By rotating a handwheel or activating an actuator, the valve stem is driven to perform a lifting motion (Outside Screw & یوغ – سیستم عامل&Y type) or remain in place while the gate moves (ساقه بدون افزایش – NRS type). This action drives the connected gate up or down within the valve body, perpendicular to the fluid channel. When the gate is fully lifted, the passage is completely open, offering minimal resistance to flow. When the gate is fully lowered and seals tightly against the valve seat, the passage is completely closed, achieving shut-off.

2. Main Advantages:

   • Low Flow Resistance: وقتی کاملا باز است, the gate is completely withdrawn from the flow path, allowing the medium to flow almost straight through, resulting in very low pressure drop.

   • Relatively Low Operating Torque: Compared to globe valves, the gate moves perpendicular to the flow direction, requiring less force to overcome fluid pressure during opening and closing.

   • No Restriction on Flow Direction: Gate valves are typically bidirectional, meaning they can be installed and operated regardless of the flow direction.

   • Wide Range of Applications: Suitable for various media (liquids, گازها, بخار, slurries, و غیره.), فشارها, and temperature ranges.

   • Relatively Simple Structure, تعمیر و نگهداری آسان.

3. Main Disadvantages:

   • Not Suitable for Throttling: In a partially open state, high-velocity fluid can easily erode the sealing surfaces, leading to valve damage and leakage. علاوه بر این, the relationship between flow rate and opening percentage is non-linear, making precise flow control difficult.

   • Slow Operation: The gate has a relatively long travel distance, requiring significant time to complete a full open or close cycle.

   • Large Overall Dimensions and Height: Especially for OS&Y types, the rising stem requires considerable overhead space when the valve is open.

   • Sealing Surfaces Prone to Abrasion: During opening and closing, relative friction occurs between the gate and seat sealing surfaces, particularly under pressure or when the medium contains solid particles.

ویژگی های شیرهای دروازه موازی

شیر دروازه موازی رایج ترین نوع دیسک دوبل است, به منظور بستن بدنه شیر و دروازه بین دو سطح آب بندی در تماس محکم, اغلب در ساندویچ دو صفحه دروازه با گوه رانش دو طرفه استفاده می شود.

به این ترتیب, هنگام بستن شیر, تماس گوه رانش دو طرفه با پایین بدنه شیر به تدریج تحت فشار قرار می گیرد, فشار دادن صفحه دروازه دوگانه به طوری که سطح آب بندی دروازه و بدنه شیر آب بندی و محکم شود.. این نوع گیت موازی دو دیسکی معمولاً برای شرایط کاری که نیازی به باز و بسته شدن مکرر ندارد اعمال می شود, و دروازه را کاملا باز یا کاملا بسته نگه دارید.

Main Structural Types:

Parallel Slab Gate Valve / Through-Conduit Gate Valve:

• • • Structure: Typically features a single, flat gate (slab) with a bore (port) machined through it, matching the pipeline diameter. The slab slides between two parallel seats.

    • Operation: To close, the slab slides down, and its solid portion blocks the flow path. To open, the slab slides up, aligning the through-conduit port with the pipeline, creating a smooth, unobstructed passage. Sealing usually relies on line pressure pushing the slab against the downstream seat (self-sealing), sometimes assisted by spring-loaded seats providing initial sealing force.

    • Advantages:

      • Minimal Flow Resistance: وقتی کاملا باز است, the port matches the pipe bore, offering a smooth, non-restrictive flow path, ideal for pipelines requiring low pressure drop, such as long-distance transport lines.

      • Sealing Surface Protection: In both fully open and fully closed positions, the sealing surfaces are shielded from the main flow, protecting them from erosion and wear, especially suitable for media containing solid particles or abrasives.

      • Suitable for Pigging: The smooth through-conduit allows pipeline inspection gauges (Pigs) to pass through.

      • Relatively Lower Operating Torque: Primarily needs to overcome friction, no wedging force involved.

    • Disadvantages:

      • Sealing tightness at low pressure might be less positive than wedge types, as self-sealing effectiveness depends on sufficient differential pressure.

      • Structural dimensions, particularly face-to-face length, can be larger.

      • Manufacturing costs can be higher, especially for large diameters and high pressure ratings.

شیر دروازه دودیسکی موازی:

• • • Structure: Comprises two parallel discs, usually with a spring or spreader mechanism (like a wedge or toggle) located between them.

    • Operation: As the gates descend near the closed position, the spring or spreader mechanism activates, forcing the two discs outwards against their respective upstream and downstream seats, achieving a double seal. During opening, this spreading force is released first, allowing the discs to lift freely.

    • Advantages:

      • Excellent Bidirectional Sealing: Provides effective sealing regardless of the direction of flow or pressure.

      • Reliable Low-Pressure Sealing: The mechanical spreading force ensures a tight seal even at very low differential pressures.

      • Avoids Thermal Binding: The absence of a wedge angle eliminates the risk of jamming due to temperature changes or pressure fluctuations, making it ideal for high-temperature, high-differential pressure, and thermal cycling applications.

      • Potential for Self-Relieving Function: Some designs allow overpressure trapped in the body cavity to automatically bleed off to the upstream side, enhancing safety (specific design must be confirmed).

    • Disadvantages:

      • Relatively complex structure with more parts, leading to higher manufacturing and maintenance costs.

      • Potential for debris accumulation between the discs, which could affect sealing or operation.

      • Typically larger and heavier than wedge gate valves of the same specification.

Parallel Gate Valve Characteristics Summary:

Advantages:

• No risk of thermal binding, suitable for high-temperature and fluctuating temperature service.

• Relatively lower operating torque (especially slab gate type).

• Through-conduit design protects sealing surfaces, suitable for particulate media and pigging operations.

• Double disc design offers reliable bidirectional and low-pressure sealing.

Disadvantages:

• Single-gate self-sealing types may have weaker sealing at very low pressures.

• Double disc types are structurally complex, costly, and bulky.

• High manufacturing precision required, especially for parallelism and flatness.

Typical Application Areas:

• Oil and gas long-distance pipelines (primarily through-conduit parallel slab gate valves, often to API 6D).

• High-temperature steam lines (e.g., main steam lines in power plants, often using double disc parallel types).

• Refineries and chemical plants for high-temperature, high-pressure services or where pigging is required.

• Low-pressure gas distribution lines.

• Applications requiring reliable bidirectional sealing.

معمولا, در صورت اتصال مستقیم با خط لوله, توصیه می شود از شیر دروازه موازی استفاده کنید, که دارای مزایای ساختار فشرده است, سبک وزن, اندازه کوچک, نگهداری آسان, عملکرد راحت و انعطاف پذیر, و غیره.

ویژگی های دریچه های گوه ای

شیر دروازه گوه ای دارای شیر گیت گوه ای تک دیسکی/دوبل. مزایای شیر دریچه گوه ای دو دیسک آب بندی است در حالی که زاویه دقت مورد نیاز کم است., تغییرات دما برای ایجاد گوه دروازه آسان نیست, سایش سطح آب بندی را می توان با افزودن واشر جبران کرد.

اشکال این است که ساختار پیچیده است, چسباندن آسان در محیط خشک, به طور عمده صفحه بافل بالا و پایین به راحتی پس از سال ها خوردگی سقوط می کند.

از این رو, شیر دروازه ای گوه ای تک دیسکی به دلیل ساختار ساده و استفاده قابل اعتماد آن در تعداد زیادی استفاده می شود, به خصوص پس از تغییر به دروازه ارتجاعی, که می تواند یک تغییر شکل الاستیک جزئی ایجاد کند تا انحراف ایجاد شده در پردازش زاویه سطح آب بندی را جبران کند..

Wedge Angle: The selection of the wedge angle is a critical design parameter, typically dependent on the medium temperature, اندازه گیری فشار, and valve size.

• Temperature Influence: Higher operating temperatures lead to more significant thermal expansion differences in materials. To prevent the gate from becoming “wedged shut” or experiencing “thermal binding” at high temperatures, a larger wedge angle is usually chosen. برعکس, for ambient or low temperatures, a smaller wedge angle can be used for better sealing and lower operating torque.

• Common Angles: Generally range from 3° to 10°. مثلا, API 600 often specifies 5° or higher.

Main Structural Types：

• Solid Wedge Gate Valve:

  • Structure: The gate is a single, solid wedge piece.

  • Advantages: Simplest structure, robust, بادوام, relatively low cost, less prone to trapping debris, suitable for most general applications, especially in small to medium sizes and low to medium pressures.

  • Disadvantages: Poor adaptability to sealing surface machining inaccuracies and valve body deformation. Temperature changes or pipeline stresses can lead to poor sealing or gate jamming (thermal binding). Closing under high differential pressure can create excessive wedging force, making opening difficult.

• Flexible Wedge Gate Valve:

  • Structure: The main body of the gate is still wedge-shaped, but features cuts, slots, or a specific peripheral design allowing it some elastic deformation capability.

  • Advantages: Can compensate for minor valve body distortions caused by temperature changes or pipeline loads, enhancing sealing reliability. Effectively prevents high-temperature thermal binding. Less demanding on the precision of sealing surface angle machining. Offers better sealing performance than solid wedges. Farpro YD Valve has mature technology in the design and manufacture of high-performance flexible wedge gate valves.

  • Disadvantages: Structure is slightly more complex than a solid wedge, leading to a marginally higher manufacturing cost. Not ideal for media containing significant solid particles or prone to scaling, which could clog the flexible structure.

• Split Wedge / Double Disc Wedge Gate Valve:

  • Structure: Consists of two independent discs (often connected by a mechanism like a ball-and-socket joint, pin, or dovetail) forming a composite wedge shape. Upon closing, external forces (like stem thrust or a bottom spreader) allow the two discs to move slightly apart laterally, pressing independently against their respective seats.

  • Advantages: Both sealing surfaces can achieve independent contact with the seats, providing excellent self-alignment. This offers better adaptability to seat angle variations and body deformation, resulting in superior sealing performance, especially under high pressure and high temperature conditions. Minor sealing surface wear can be compensated for by the outward movement of the discs. Less prone to thermal binding.

  • Disadvantages: Most complex structure, more parts, higher manufacturing cost, relatively more difficult to assemble and repair. Potential for media to become trapped between the discs. In designs with bottom guides, corrosion and detachment of these guides over time can impair function.

Wedge Gate Valve Characteristics Summary:

• Advantages:

  • عملکرد آب بندی عالی: Relies on wedging action for positive sealing, providing high sealing pressure and reliability.

  • Relatively compact structure (compared to parallel gate valves of the same size).

  • Wide range of applications: Suitable for various pressures, دما, and media (selection depends on materials and specific structure).

  • Mature technology, highly standardized (e.g., API, ASME standards).

• Disadvantages:

  • Risk of thermal binding: Especially with solid wedges in applications with significant temperature fluctuations or cooling after high-pressure closure.

  • Relatively high operating torque: Must overcome the friction associated with the wedging action.

  • Sealing surfaces prone to wear: Due to relative sliding friction during operation.

  • Not suitable for rapid opening/closing.

Typical Application Areas:

• صنعت برق (خطوط بخار, feedwater systems, ash handling systems, و غیره.)

• Oil and gas (oilfields, پالایشگاه ها, some pipeline applications)

• صنایع شیمیایی (various process fluid lines)

• Metallurgy and mining (process water, slurry handling, و غیره.)

• Municipal water supply and wastewater treatment

• General industrial services

به طور کلی, ساقه دریچه گوه ای گرم شده و سطح نیترید شده است تا مقاومت خوبی در برابر خوردگی و ضد خراش داشته باشد.. درب و مهر و موم صندلی از جوشکاری روکش آلیاژی سخت ساخته شده است, که در برابر سایش مقاوم است, مقاوم در برابر درجه حرارت بالا, مقاوم در برابر خوردگی, عملکرد ضد خراش خوب و عمر طولانی. تنوع مواد بدنه سوپاپ کامل است, بسته بندی, واشر با توجه به شرایط کاری واقعی یا نیازهای کاربر منطقی اختیاری است, را می توان برای انواع فشار اعمال کرد, شرایط کار دما و رسانه.

Wedge Gate Valve vs. Parallel Gate Valve – In-Depth Comparison

To aid in making a clearer choice, we directly compare these two valve types across several key dimensions:

Selection and Purchasing Guidance – Professional Advice from Farpro YD Valve

Choosing between a wedge gate valve and a parallel gate valve isn’t about determining which one is universally “better,” but rather identifying which one is “more suitable” for a specific application. As a responsible valve supplier, Farpro YD Valve recommends considering the following key factors during selection:

Operating Conditions are Fundamental:

• Media Properties: Is it a clean fluid, گاز, بخار, or does it contain solid particles, دوغاب, viscous material, or crystallizing substances? This directly impacts whether sealing surface protection is needed (advantage: parallel slab gate) or if specific materials and structures are required.
• امتیاز فشار: In high-pressure applications, the positive sealing of a wedge gate valve (especially split wedge) can be very reliable, but consider the operating torque and potential binding issues under high differential pressure. Parallel double disc types also perform well under high pressure.
• Temperature Range & Fluctuation: For high temperatures or significant temperature swings, parallel gate valves (lacking a wedge angle) are the preferred choice to avoid thermal binding. If selecting a wedge type, prioritize flexible wedge or split wedge designs and pay attention to the wedge angle selection.

Functional Requirements Guide the Choice:

• Sealing Level Requirement: Is zero leakage or a very high sealing class required? Split wedge and parallel double disc types generally offer superior sealing performance.
• Operating Frequency: Gate valves are inherently unsuitable for frequent operation. If relatively frequent cycling is necessary, consider a parallel gate valve with lower operating torque or select an appropriate actuation method.
• Need for Pipeline Pigging: For applications like long-distance pipelines where pig passage is required, a through-conduit parallel gate valve is mandatory.
• Need for Automatic Cavity Pressure Relief: Certain parallel double disc gate valves offer this safety feature; confirm based on specific process requirements.

Economic and Maintenance Considerations:

• • Initial Purchase Cost: بطور کلی, solid/flexible wedge gate valves have the lowest cost, followed by slab gate and split wedge types, with double disc parallel gate valves typically being the most expensive. با این حال, this is a general guideline influenced by materials, standards, brand, و غیره.

  • Maintenance Convenience and Cost: Simpler structures usually mean easier maintenance. Consider the valve’s expected lifespan, maintenance intervals, and replacement costs.

  • Space and Weight Constraints: Parallel gate valves are often larger and heavier, requiring consideration of installation space and support structures.

Industry Codes and Standards:

• • Ensure the selected valve complies with relevant industry codes (e.g., روغن & گاز, قدرت, شیمیایی) and standards (e.g., API, مثل من, IN, گیگابایت). All Farpro YD Valve products are designed and manufactured in strict accordance with international and national standards.

Purchasing Recommendations

• Define Needs Clearly, Communicate Thoroughly: Before inquiring or purchasing, provide your supplier (like Farpro YD Valve) with detailed operating parameters and functional requirements. Our technical team will leverage your specific needs to recommend the most suitable valve type and specification.

• Focus on Quality and Brand Reputation: Valves are critical equipment; choosing a reliable brand with a proven quality record is essential. Farpro YD Valve operates under robust quality management systems (e.g., ISO 9001) and utilizes advanced manufacturing and testing equipment to ensure every valve meets high-quality standards.

• Consider Total Cost of Ownership (TCO) / Lifecycle Cost: Look beyond the initial purchase price. Evaluate the valve’s performance, قابلیت اطمینان, عمر سرویس, maintenance costs, and the potential costs associated with failure. Choosing a high-performance, long-lasting valve (even if initially more expensive) often yields better long-term economic benefits.

• Value Technical Support and Service: Select a supplier capable of providing professional technical consultation, selection guidance, after-sales service, and spare parts availability. Farpro YD Valve is committed to offering a seamless and supportive experience for our customers.

نتیجه گیری

Wedge gate valves and parallel gate valves, as two major branches of the gate valve family, each possess unique design philosophies, performance advantages, and application niches.

• Wedge gate valves, with their powerful wedging seal, relatively compact structure, and broad applicability, dominate many conventional industrial sectors. Derived designs like the flexible wedge and split wedge further enhance performance and reliability.

• Parallel gate valves, characterized by their immunity to thermal binding, suitability for high temperatures and particulate media (through-conduit type), and excellent bidirectional and low-pressure sealing capabilities (double disc type), demonstrate irreplaceable advantages in specific high-end applications and demanding operating conditions, such as long-distance pipelines and high-temperature steam systems.

There is no absolute superiority, only relative suitability. Understanding their core differences and making scientific selections based on specific application requirements are prerequisites for ensuring the safe, کارآمد, and economical operation of fluid control systems.

Farpro YD Valve offers a comprehensive product line of both wedge and parallel gate valves, covering various materials, pressure ratings, actuation methods, and standard compliance. We not only provide standardized high-quality products but also offer customized solutions tailored to your unique needs. Whatever fluid control challenges you face, our professional team is ready to provide the most accurate selection advice and the highest quality valve products.

Choose Farpro YD Valve – Choose Professionalism, Choose Reliability. We welcome you to contact us anytime to discuss your valve requirements!