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Wholesale Parallel Double Expansion Gate Valve

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Parallel Double Expansion Gate Valve

The Parallel Double Expansion Gate Valve is a highly dependable valve designed for efficient and secure fluid control in industrial applications. It is engineered to ensure smallest pressure drop and turbulence while providing good sealing performance, even under fluctuating temperatures. This valve is widely used in oil, gas, and chemical industries due to its robust construction, bi-directional flow capability, and good sealing technology.

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  • Technical Specifications
    - Design & Manufacturing Standard: API 6D
    - Face-to-Face Standard: ASME B16.10 / API 6D
    - Flanged Ends Standard: ASME B16.5 / MSS-SP-44
    - Testing & Inspection Standard: API 598 / API 6D
    - Material Options: Carbon Steel, Stainless Steel, Alloy Steel, Monel, Duplex, Inconel
    - Size Range: 2” – 72”
    - Pressure Rating: Class 150 – Class 2500
    - End Connections: RF, RTJ, BW
    - Operating Temperature: -46°C to +200°C
    - Operation Modes: Handwheel, Gearbox, Electric, Pneumatic

Fangyuan Valve Group Co., Ltd.
ABOUT US
Founded in 1998, Fangyuan Valve Group Co., Ltd. is a Wholesale Parallel Double Expansion Gate Valve Supplier and Custom Parallel Double Expansion Gate Valve Company for the petroleum, petrochemical, and energy sectors. With over 20 years of experience, FYV offers comprehensive valve solutions supported by advanced R&D and manufacturing capabilities.
Headquartered in Wenzhou, FYV operates large-scale, modern production facilities and produces a wide range of valves, including gate valves, ball valves, control valves, globe valves, check valves, butterfly valves, and high-pressure injection valves. Committed to innovation, quality, and sustainability, FYV aims to become a century-old brand in the valve industry.
Certificate
  • API-6FA-150lb-NPS16-and-above-01

    API-6FA-150lb-NPS16-and-above-01

  • API-6FA-150lb-NPS16-and-above-02

    API-6FA-150lb-NPS16-and-above-02

  • API-6FA-300lb-NPS16-and-above-01

    API-6FA-300lb-NPS16-and-above-01

  • API-6FA-300lb-NPS16-and-above-02

    API-6FA-300lb-NPS16-and-above-02

  • API-6FA-600lb-NPS16-and-above-01

    API-6FA-600lb-NPS16-and-above-01

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Industry Knowledge Expansion

Features of Expanding Gate Valve

Expanding gate valves are designed to provide a tight mechanical seal, which makes them particularly effective in applications where zero leakage is required. One of the main features of these valves is the two-piece gate assembly—typically consisting of a segment gate and a spreading mechanism, often a floating or fixed wedge. When the valve is closed, these two components move apart, pushing tightly against the seat rings on either side of the valve, resulting in a reliable seal.

Another important feature is the ability of the expanding gate valve to isolate pressure on both the upstream and downstream sides. This double isolation capability enhances safety and makes the valve suitable for critical service applications, including pipeline systems for oil and gas, where precise shutoff is necessary.

Expanding gate valves also offer bidirectional sealing. This means they can effectively stop the flow from either direction, making them more versatile than some other types of gate valves. The robust construction and mechanical sealing mechanism contribute to long service life and reduced maintenance requirements, especially in environments where frequent operation and pressure variations are expected.

Structure of Through Conduit Expanding Gate Valve

The through conduit expanding gate valve is a specialized version of the standard expanding gate valve. Its structure includes a full bore opening, allowing pigs or scrapers to pass through the valve when it is in the open position. This design makes it especially valuable in pipeline applications that require maintenance or cleaning operations.

The main components of this valve include the body, bonnet, stem, gate assembly, seat rings, and seals. The gate assembly is the core of the expanding mechanism, typically comprising two segments that expand outward when the valve is closed. This movement ensures tight contact with the seats on both ends, achieving a reliable seal. The seats themselves are often fixed and metal-to-metal, though in some cases, elastomeric materials are used for additional sealing support.

The valve stem is usually of a rising type, which allows for easy visual confirmation of the valve’s position. The body is designed to withstand high pressure and temperature conditions and often includes corrosion-resistant linings or materials.

Another notable structural feature is the inclusion of guide rails or tracks inside the body, which ensure precise alignment of the gate segments during opening and closing. Some designs also incorporate pressure relief mechanisms or grease injection points to enhance operability under demanding conditions.

Because of its full-bore, unobstructed design, the through conduit expanding gate valve minimizes pressure drop across the valve and supports uninterrupted flow when open. This structure is especially beneficial in long-distance pipelines where efficiency and safety are top priorities.

Use of Soft Seated Gate Valve

Soft seated gate valves are used in systems where tight shutoff and resistance to leakage are critical, especially at lower pressures and moderate temperatures. Unlike metal seated valves, soft seated gate valves incorporate non-metallic materials such as PTFE, rubber, or other elastomers in the seat area. These materials allow for a more adaptable and tighter seal, which can be especially useful in applications involving clean water, chemicals, and gas distribution.

One common application is in municipal water supply networks, where maintaining a leak-free system is essential for conservation and operational efficiency. In such systems, the soft seat material conforms more easily to the gate surface, compensating for minor misalignments or wear and tear over time.

Another area where soft seated gate valves are prevalent is in food and beverage processing, where sanitary conditions are paramount. The non-metallic materials used in the seating surfaces reduce the risk of contamination and are often easier to clean and maintain.

These valves are also suitable for systems requiring frequent opening and closing. The soft seat reduces wear on both the gate and the seat itself, helping to maintain performance over many cycles. While they are not typically used in high-temperature or high-abrasion environments due to the limitations of the seat materials, they provide an solution in moderate-duty systems where sealing integrity is essential.