An API 602 forged gate valve is used for compact, small-bore gate valve service in petroleum, natural gas, chemical, power, and industrial piping. To specify the right design, confirm size, pressure class, material, bonnet type, end connection, port type, trim, seat, testing standard, and service conditions.   What Is an API 602 Forged Gate Valve?   An API 602 forged gate valve is a compact steel gate valve manufactured to API 602 requirements. API 602 covers gate, globe, and check valves for sizes DN 100 / NPS 4 and smaller in petroleum and natural gas industry applications. Unlike large cast steel gate valves, forged gate valves are usually selected for smaller piping systems where pressure, temperature, vibration, or compact installation matters. Forged construction provides a dense material structure, which is useful for high-pressure and critical service. In simple terms, API 602 is often the better fit when the line is small but the service is demanding.   When Should You Use an API 602 Forged Gate Valve?   Use an API 602 forged gate valve when the application requires reliable isolation in a compact piping system. It is commonly used in refineries, chemical plants, power plants, oil and gas facilities, steam lines, vents, drains, and utility systems.   Typical use cases include: ● Small-bore high-pressure lines ● Steam and condensate service ● Process isolation ● Skid-mounted systems ● Drain and vent connections ● Instrument and auxiliary piping ● Oil, gas, and petrochemical service   For larger line sizes or heavy-duty cast steel applications, API 600 may be more appropriate. API 602 and API 600 should not be treated as interchangeable standards.   Key Design Choices to Specify   Do not specify an API 602 forged gate valve only by size and pressure class. The purchase requirement should define the full valve design. Important items include: Item What to Confirm Size DN / NPS size and bore requirement Pressure class Class 800, 1500, 2500, or project requirement Material A105, F304, F316, F11, F22, LF2, or other grade Bonnet type Bolted bonnet, welded bonnet, or pressure seal End connection Socket weld, threaded, butt weld, or flanged Port Full port or regular port Trim Stem, wedge, seat, and hardfacing material Operation Handwheel, gearbox, or actuator if required Testing API 598 or project-specified testing   These details affect sealing, pressure capability, maintainability, and installation.   Bonnet and End Connection Selection   Bonnet type should match pressure, temperature, and maintenance needs. Bolted bonnet designs are common and easier to service. Welded bonnet designs reduce potential leakage paths but are less convenient to disassemble. Pressure seal bonnets may be considered for higher-pressure service, depending on the design and project requirement.   End connection is equally important. Socket weld ends are common for small-bore forged valves. Threaded ends may be...

The main butterfly valve types include concentric, double offset, triple offset, wafer, lug, flanged, soft-seated, metal-seated, manual, pneumatic, and electric butterfly valves. The right choice depends on pressure, temperature, media, leakage requirement, installation space, and operation frequency.   What Are the Main Butterfly Valve Types?   Butterfly valves are usually classified by disc design, body connection, seat material, and actuation method. This classification is important because two valves may both be called butterfly valves, but their service limits can be very different.   A butterfly valve uses a rotating disc to isolate or regulate flow. Because of its compact structure, light weight, and quarter-turn operation, it is widely used in water treatment, power plants, chemical processing, HVAC, marine systems, and general industrial pipelines.   For buyers, the key question is not simply “which type is cheaper?” It is “which type can handle the actual pressure, temperature, media, and sealing requirement?”   Concentric Butterfly Valve   A concentric butterfly valve has the stem located on the centerline of the valve body and disc. It is also called a centerline butterfly valve. This type is commonly used for low-pressure and general-service applications, especially with water, air, and non-aggressive fluids. It is simple, economical, and easy to maintain.   The limitation is seat wear. During opening and closing, the disc stays in contact with the soft seat for much of its movement. For higher pressure, higher temperature, or stricter shutoff requirements, double offset or triple offset designs are often more suitable.   Double Offset Butterfly Valve   A double offset butterfly valve uses two offsets to reduce friction between the disc and seat. This improves sealing performance and helps extend service life compared with a basic concentric design.   Double offset butterfly valves are often selected for medium-pressure industrial service, including oil and gas, water supply, power generation, and chemical systems. They are useful when the application needs better durability but does not require a full metal-seated triple offset design.   This type is also commonly called a high-performance butterfly valve. Before selection, buyers should confirm the pressure class, seat material, shaft sealing design, and expected operation frequency.   Triple Offset Butterfly Valve   A triple offset butterfly valve adds a third geometric offset to create a more advanced sealing structure. It is typically used for high-temperature, high-pressure, or severe-service applications. The design reduces rubbing between the sealing surfaces during operation. Many triple offset butterfly valves use metal seats, making them suitable for steam, oil and gas, chemical, and other demanding media.   For these applications, standards and testing matter. Buyers often need t...

A triple offset butterfly valve is a high-performance isolation valve designed for applications where conventional resilient-seated or double offset butterfly valves cannot meet pressure, temperature, or leakage requirements. By using a three-offset sealing design, the valve achieves a metal-to-metal sealing mechanism with reduced friction between the disc and seat during operation, making it suitable for demanding services such as oil and gas, petrochemical, power generation, LNG, steam, and industrial process systems.   Triple Offset Butterfly Valve Design and Working Principle   Unlike a concentric butterfly valve, where the shaft is positioned at the centerline of the disc and seat, a triple offset butterfly valve incorporates three independent geometric offsets. The first offset moves the shaft away from the centerline of the valve body, the second offset shifts the shaft from the pipeline centerline, and the third offset introduces a conical sealing surface instead of a circular sealing profile. This geometry allows the disc to move away from the seat immediately after rotation begins, eliminating rubbing between sealing surfaces.   The main advantage of this design is that the sealing force is generated by torque rather than continuous compression of soft materials. If the application requires high-temperature service, then a metal-seated triple offset butterfly valve is often preferred because elastomer seats may degrade under elevated temperatures. If the medium contains abrasive particles or aggressive chemicals, then material selection for the disc, seat, and body becomes critical to prevent erosion, corrosion, and leakage during long-term operation.   Triple Offset Butterfly Valve Standards and Materials   A triple offset butterfly valve is commonly manufactured according to standards such as API 609, EN 593, and ISO 5752, with pressure ratings ranging from Class 150 to Class 600 and higher depending on design requirements. Typical materials include carbon steel, stainless steel, duplex stainless steel, aluminum bronze, and nickel-based alloys. For corrosive seawater applications, aluminum bronze alloys such as C95500 or C95800 may be selected, while sour service applications may require materials compliant with NACE MR0175/ISO 15156 requirements.   Triple Offset Butterfly Valve Sealing Performance and Leakage Control   The sealing performance of a triple offset butterfly valve depends on the interaction between the sealing ring, seat surface finish, operating torque, and material compatibility. Since the sealing surfaces contact only at the final closing position, mechanical wear is significantly reduced compared with traditional butterfly valve designs. If zero leakage is required for critical isolation, then the valve design, pressure class, and applicable leakage standard, such as API 598 or ISO 5208, must be considered during specification.   Triple Offset Butterfly Valve Applications and S...

Ball valves and plug valves are both quarter-turn rotary valves used for on-off control and isolation in industrial piping systems. Although they share similar operating principles, their internal designs result in different performance characteristics, especially in terms of sealing, pressure capability, operating torque, maintenance requirements, and suitability for different media.   The selection between a ball valve and a plug valve should be based on actual operating conditions rather than valve type preference. If the application requires tight shutoff, frequent operation, and low operating torque, then a ball valve is often preferred. If the system involves dirty media, abrasive particles, or large flow passages, then a plug valve may provide better reliability.   Design Differences and Sealing Performance   A ball valve uses a spherical closure element with a drilled bore. When the valve is open, the bore aligns with the pipeline to provide a nearly unrestricted flow path. When rotated 90 degrees, the solid section of the ball blocks the passage and provides shutoff.     A plug valve uses a cylindrical or conical plug with a flow passage through the center. The plug rotates inside the body to control flow. Depending on the design, plug valves can be lubricated, sleeved, or non-lubricated, with each structure offering different sealing characteristics.   The sealing mechanism is one of the main differences between the two valves. Ball valves generally use soft seats, metal seats, or a combination of both to achieve reliable shutoff. If the system requires bubble-tight isolation, especially in gas service or critical process applications, then a properly selected ball valve can provide excellent sealing performance.   Plug valves rely on the contact between the plug and the valve body or sleeve. Lubricated plug valves use sealant injected between the plug and body to reduce friction and improve sealing. This design can perform well in applications where the media contains contaminants because the sealant helps protect the sealing surfaces.   Application Considerations   Operating conditions determine whether a ball valve or plug valve is more suitable.   Ball valves are widely used in oil and gas, petrochemical, LNG, chemical processing, and power industries where reliable shutoff is required. Floating ball valves are commonly applied in lower pressure systems, while trunnion mounted ball valves are preferred for larger sizes and higher pressure ratings because the trunnion support reduces operating torque.   If the valve will experience frequent cycling, then a ball valve usually provides an advantage due to its low friction operation and quarter-turn actuation. However, careful consideration is required when handling fluids containing solid particles. If abrasive particles become trapped between the ball and seat, then seat damage and leakage may occur.   Plug valves are often s...

In 2026, DERVOS VALVE proudly celebrates its 18th anniversary, marking an important milestone in the company's journey. To commemorate this occasion, DERVOS VALVE organized a three-day anniversary celebration, bringing together all employees to reflect on the company's achievements over the past eighteen years, look ahead to future development, and further strengthen team cohesion through meaningful activities and shared experiences.   Reflecting on 18 Years of Growth   From raw material management and precision machining to assembly and product testing, every stage of production reflects DERVOS VALVE's unwavering commitment to quality.   Over the past eighteen years, DERVOS VALVE has continuously improved its manufacturing system while enhancing product quality and customer service capabilities. Today, our industrial valves are widely used across the oil and gas, chemical, power generation, water treatment, LNG, and other industrial sectors, providing reliable valve solutions to customers worldwide.   Building Consensus for Future Development     During the anniversary celebration, DERVOS VALVE also held its mid-year communication meeting.   The meeting reviewed the company's performance over the first half of the year and outlined key objectives for future development. Representatives from different departments exchanged insights on production management, quality improvement, and cross-functional collaboration, sharing practical experience, reviewing achievements, and discussing future goals together.   The meeting further strengthened communication among departments, reinforced team alignment, and injected new momentum into the company's long-term development.     Embracing Nature Together   In addition to the company's anniversary activities, DERVOS VALVE organized a group excursion to experience the beauty of nature.   Surrounded by picturesque landscapes, employees enjoyed the scenic environment and explored the local culture in a relaxed and enjoyable atmosphere. The trip provided an opportunity to unwind while fostering stronger relationships among colleagues.   This memorable experience enriched the anniversary celebration, strengthened team spirit, and inspired everyone with renewed energy for the work ahead.     Eighteen Years of Commitment, Looking Ahead   Eighteen years represent not only growth and achievement, but also the beginning of a new chapter.     Since its establishment, DERVOS VALVE has remained dedicated to the design, manufacturing, and global supply of industrial valves. Through continuous improvements in product development, manufacturing capabilities, and quality management, the company has provided reliable valve products and technical support to customers across a wide range of industries worldwide.   Looking ahead, DERVOS VALVE will continue to focus on product innovation, manufacturing excellence, and long-term...

Refineries operate under some of the most demanding process conditions found in the energy industry. High pressure, elevated temperature, sour media, corrosive fluids, and frequent thermal cycling place strict requirements on valve performance. In these environments, ball valves are widely used because they provide reliable shutoff, low pressure loss, and fast operation. However, selecting the best ball valve for refinery applications depends less on the valve type itself and more on matching the design to the process conditions.   Why Ball Valves Are Common in Refinery Service   Refinery units handle hydrocarbons, hydrogen, steam, sulfur compounds, and various aggressive chemicals. If bubble-tight isolation is required, then trunnion mounted ball valves are generally preferred for larger sizes and higher pressure classes because seat loading remains stable under differential pressure. Floating ball valves are more common in small-bore lines where compact dimensions and simple construction are advantageous.   API 6D and ASME B16.34 designs are frequently specified for refinery piping systems. Fire-safe construction in accordance with API 607 or API 6FA is often mandatory because accidental loss of soft seats must not result in external leakage. If the process medium contains hydrogen sulfide, then materials must comply with NACE MR0175 to reduce the risk of sulfide stress cracking.   Material Selection Depends on Process Media   Material compatibility is one of the primary factors affecting service life. Carbon steel valves are suitable for many hydrocarbon services, while stainless steel provides improved corrosion resistance in wet and chemically aggressive environments. Duplex and super duplex stainless steels are selected when chloride-induced corrosion becomes a concern.   If the process contains sulfur compounds or sour gas, then hardness control and material qualification become critical. In high-temperature applications, thermal expansion must be considered because excessive growth can increase operating torque and accelerate seat wear. If severe erosion is expected, then hard-faced balls and seats with tungsten carbide or chromium carbide coatings can significantly improve durability.   Sealing Performance and Failure Prevention   Soft-seated ball valves provide excellent shutoff performance, but seat materials determine their temperature limits. PTFE and reinforced PTFE are common in moderate-temperature services, while PEEK offers improved mechanical strength and higher temperature capability. If temperatures exceed the limits of polymer seats, then metal-seated ball valves become a more suitable solution.   Most valve failures in refineries are related to seat damage, stem leakage, or corrosion. If particulate contamination is present, then cavity fillers or metal seats may reduce wear. Double block and bleed configurations are often used where positive isolation is required for maintenance...