Wholesale Through Conduit Seated Expanding Gate Valve Factory

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.

Specification
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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
Key Advantages of the Parallel Double Expansion Gate Valve
1. Bi-Directional Full Port Flow
The Parallel Double Expansion Gate Valve allows full port bi-directional flow, reduced to a certain extent turbulence and pressure drop. This ensures best efficiency in pipeline systems and facilitates smooth operation under varying flow conditions.

2. Parallel Expanding Seal Mechanism
The valve obturator consists of two parallel sealing surfaces that maintain effective sealing even when thermal expansion occurs. This prevents the risk of gate jamming due to temperature-induced deformation, making it a reliable solution for high-temperature applications.

3. Durable Sealing Surface
The sealing surface is constructed using hard alloy materials that exhibit good corrosion and wear resistance. This design enhances the sealing integrity and extends the operational lifespan of the Parallel Double Expansion Gate Valve even in harsh environments.

4. Double Block and Bleed Capability
This feature ensures secure isolation of fluids within the pipeline, making the Parallel Double Expansion Gate Valve ideal for applications where fluid containment and pressure control are critical.

5. Internal Cavity Pressure Relief
The valve incorporates an internal cavity pressure relief mechanism to prevent excessive pressure buildup within the valve body. This enhances operational safety and maintains performance consistency.

6. Enhanced Sealant Injection System
Equipped with sealant injectors for both seats and stem, the Parallel Double Expansion Gate Valve provides additional sealing reliability, reducing the risk of leakage and ensuring smooth long-term operation.

Applications
The Parallel Double Expansion Gate Valve is widely utilized in various industries where secure fluid control is essential. It is particularly suitable for:
- Transmission pipeline systems handling natural gas, crude oil, and refined petroleum products
- Chemical processing plants where resistance to corrosion and high-pressure conditions is required
- Industrial gas distribution networks ensure smooth and reliable flow regulation
- Offshore and onshore oil fields, where operational efficiency and durability are of high quality

Design Features
- Full Bore Port allowing pigging operations and reducing pressure loss
- Fully Protected Seat Sealing Faces to minimize wear and tear
- Robust Mechanical Seal ensuring high and low-pressure reliability
- Efficient Pressure Management with cavity pressure relief
- Versatile Actuation Options including manual, pneumatic, and electric controls

The Parallel Double Expansion Gate Valve is a good choice for industries requiring efficient and reliable fluid control. With its robust design, durable sealing mechanism, and advanced pressure management features, this valve ensures long-term performance and operational safety. Whether used in natural gas pipelines, oil refineries, or chemical processing plants, it delivers special sealing integrity and smallest maintenance requirements. Its bi-directional flow capability, combined with advanced sealing technology, makes it a first-choice solution for demanding industrial applications.
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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.