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DERVOS 18th Anniversary | Eighteen Years of Progress, Moving Forward Together
DERVOS 18th Anniversary | Eighteen Years of Progress, Moving Forward Together
2026-07-03

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...

Best Ball Valves for Refinery Applications
Best Ball Valves for Refinery Applications
2026-06-23

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...

Fully Welded Ball Valve vs. Threaded Ball Valve: Which Offers Better Pressure Resistance?
Fully Welded Ball Valve vs. Threaded Ball Valve: Which Offers Better Pressure Resistance?
2026-06-11

In natural gas transmission, district heating networks, petrochemical facilities, and industrial utility systems, ball valves are widely used for reliable flow isolation. One of the most common questions during valve selection is: Which provides better pressure resistance—a fully welded ball valve or a threaded ball valve?   Understanding the Structural Difference Between Fully Welded and Threaded Ball Valves   From a structural perspective, fully welded ball valves generally offer higher pressure-bearing capability. The valve body is manufactured using a fully welded construction, eliminating threaded body connections and reducing stress concentration points associated with mechanical joints. Under high-pressure conditions, frequent pressure fluctuations, or significant temperature changes, the welded structure can provide greater mechanical integrity and more stable sealing performance. Threaded ball valves, by contrast, rely on threaded connections to assemble the valve body. While this design simplifies installation and maintenance, threaded joints are inherently more susceptible to stress and deformation. As system pressure increases or when vibration and thermal expansion-contraction cycles are present, threaded connections may become vulnerable to loosening, potentially resulting in external leakage. Common field indications include leakage around the stem packing area, seepage from body connections, or accelerated wear of sealing components.   Why Fully Welded Ball Valves Typically Offer Higher Pressure Resistance   The primary advantage of a fully welded ball valve lies in its one-piece welded body construction. Without threaded body joints, the valve can better withstand internal pressure loads and reduce the possibility of leakage caused by connection failure.   In applications involving high operating pressures, pressure surges, or repeated thermal cycles, the welded structure maintains better dimensional stability and structural strength. This is one of the key reasons why fully welded ball valves are widely used in gas transmission pipelines, district heating systems, and other critical infrastructure projects.   How Sealing Performance Affects Pressure Capability   In high-pressure service, valve failure is not determined solely by body strength. The sealing system also plays a critical role. Fully welded ball valves typically utilize an integral body design that minimizes potential external leakage paths and provides more consistent support for the seat sealing surfaces.   In threaded ball valves, small dimensional changes at threaded joints during long-term pressure cycling may affect seat loading, potentially increasing the risk of internal leakage. If significant leakage, abnormal deformation, or pressure test failure is observed, the valve should be removed from service and inspected immediately. For flammable, toxic, or high-temperature media, disassembly and maintenance under pre...

Sliding Type Line Blind Valve
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Sliding Type Line Blind Valve 10" Class 300 ASME B16.34, Manual Screw-Operated

  • Payment:

    30% when order confirmed, 70% before shipment
  • Product Origin:

    china
  • Color:

    Customization
  • Shipping Port:

    Shanghai, China
  • Lead Time:

    30~60 days Ex Works after order confirmation
  • Material:

    A105 Forged Carbon Steel
  • Method of Operation:

    Manual Screw-Operated
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Product Detail

Introduction

 

This 10" Class 300 Sliding Line Blind Valve provides absolute positive isolation for medium‑ to high‑pressure pipelines, combining the reliability of a solid physical barrier with the simplicity of manual screw‑operated actuation.

 

Unlike conventional valves that rely on seats prone to wear, the sliding blind mechanism creates a true physical barrier, ensuring zero leakage during maintenance without the need for system depressurization. This significantly reduces downtime and enhances personnel safety.

 

The manual screw‑operated design offers precise, controlled movement of the blind plate, with inherent self‑locking capability to maintain position under pressure—ideal for applications where electric or pneumatic power may not be available or preferred.

 

Constructed to ASME B16.34 with RF flanges per ASME B16.5, this valve is available in forged carbon steel (A105), stainless steel, or alloy materials to suit your service conditions. Each unit is 100% pressure tested to API 598.

 

This 10" Class 300 configuration is a popular choice for steam, oil, gas, and chemical pipelines. Other sizes from 1" to 60" and pressure classes up to Class 2500 are available as part of our full line blind valve series.

 

THD-Slide Cutout

Slide Line Blind Suppliers

 

Features

 

1.Manual Screw‑Operated with Self‑Locking

Precision screw drive allows smooth, controlled positioning of the blind plate. The self‑locking mechanism maintains position under pressure without additional braking devices.

 

2.Absolute Physical Isolation

Solid blind plate creates a true barrier, ensuring zero leakage during maintenance—unlike seat‑dependent valves that can wear or degrade over time.

 

3.Inline Operation Without Depressurization

Sliding mechanism enables switching between flow and blind positions without system blowdown, reducing downtime and product loss.

 

4.10″ Class 300 – The Optimal Balance

Offers higher pressure capability than Class 150 while remaining more economical than Class 600, making it a versatile choice for a wide range of industrial applications.

 

5.Forged Carbon Steel Construction

A105 forged body provides high strength, impact resistance, and reliable performance under thermal cycling.

 

6.Tested to API 598

100% hydrostatic and pneumatic testing ensures leak‑tight performance before shipment.

 

Standard Specifications

 

Parameter

Specification

Type

Sliding Line Blind Valve

Size

10″ (DN250)

Pressure Rating

Class 300 (PN50)

Connection

RF Flange, ASME B16.5

Operation

Manual Screw-Operated (Self-locking)

Body Material

A105 Forged Carbon Steel (other alloys available)

Seal / Seat Material

Metal-to-Metal (Stainless Steel + Graphite)

Design Standard

ASME B16.34

Face-to-Face Dimension

Per ASME B16.10 or manufacturer standard

Test & Inspection

API 598 (100% hydrostatic & pneumatic)

Temperature Range

-29°C to +425°C (depending on sealing)

Applicable Media

Steam, Oil, Gas, Water, Hydrocarbons

Application

Pipeline isolation, refineries, petrochemical plants, power generation

 

Technical Drawing

Line Blind Valve China

Flexible Design Options

 

Tailored Configurations for Demanding Applications

Beyond the base model, this line blind valve can be customized for high-temperature service, fire-safe requirements, and zero-emission (drip-proof) operation. For installations where space is at a premium, a compact variant is available, offering the same robust isolation performance in a reduced footprint.

 

Simplified Seal Maintenance– No Disassembly Required

 

Seals are integrated into the spectacle plate, allowing operators to inspect or replace them without dismantling the valve. Condition checks can be performed while the valve remains in service, before any position change, ensuring seal integrity is verified before operation.

 

Low Total Cost of Ownership

 

The valve’s streamlined, heavy‑duty construction delivers reliable positive shut‑off with minimal upkeep. Its unique actuation mechanism allows a single operator to quickly and safely isolate the pipeline—no tools required—reducing labor time and simplifying maintenance procedures.

 

Options

 

●Hand Wheel Extensions

●Locking Device

●Limit Switches

●Drain/Vent ports

●Spectacle Plate Covers to Protect Seals

●Compact Design (integral tapped end flange)

●Rain/Dust Shield

●Torque Limiter

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    If you are interested in our products and want to know more details,please leave a message here,we will reply you as soon as we can.

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