Design and Benefits of Triple-offset Multi-Layer Butterfly Valves

 
In the modern industry, butterfly valves serve as crucial components for controlling the flow and pressure of fluids, and are widely used in industries such as petroleum, chemical, and power. The triple-offset multi-layer butterfly valve, with its unique design and excellent performance, has become an ideal choice for demanding working conditions. This type of valve not only has outstanding sealing and control capabilities but also performs well in terms of economy and safety. This article will delve into the design principles, key features, and advantages of the triple-offset multi-layer butterfly valve in practical applications, revealing how it ensures efficient and stable operation in various harsh environments.

Design and Specifications

The triple-offset multi-layer butterfly valve is designed and manufactured according to the API 609 standard, aiming to ensure efficient and stable operation under various working conditions. The design includes the following key features.

1. Thrust Ring Design

To prevent deformation of the disc due to fluid pressure and temperature changes, misalignment of the valve stem, or biting of the sealing surface, the triple-offset multi-layer butterfly valve is equipped with an independent thrust ring on both the top and bottom sides of the disc. These thrust rings effectively stabilize the disc, ensuring the normal operation of the valve under high pressure and extreme temperature conditions.

2. Stem Blow-Out Prevention Mechanism

To prevent safety accidents caused by valve stem damage or accidental blow-out, the valve is designed with two independent stem blow-out prevention mechanisms inside and outside. This design enhances the safety of the valve, allowing it to withstand pressures up to 2500 pounds, and is widely applicable to industrial environments requiring high safety.

Control Capability and Economic Benefits

The triple-offset multi-layer butterfly valve stands out in the field of control, mainly reflected in the following aspects.

1. Efficient Control

 
The triple-offset multi-layer butterfly valve adopts a triple-offset structure, and its sealing principle allows the disc to almost not rub against the seat during the opening and closing process. This design effectively avoids the common jumping phenomenon during the opening process of traditional valves, while eliminating the instability of control caused by friction in the low opening range. The triple-offset multi-layer butterfly valve can enter the controllable area from an opening of close to 0 degrees, and its control ratio is more than twice that of general butterfly valves, up to 100:1. This makes it particularly outstanding in applications that require precise flow and pressure control.

2. Economic Benefits

In large-caliber applications, the economic advantages of the triple-offset multi-layer butterfly valve are particularly evident. Traditional globe valves are extremely expensive in large calibers and difficult to achieve zero leakage. In contrast, the triple-offset multi-layer butterfly valve not only has excellent control capabilities but also effectively achieves the shut-off function, thus avoiding the need to install a shut-off valve next to the globe valve. This design not only reduces the overall equipment cost but also enhances the economy and reliability of the system.

Seat Construction and Sealing Performance

The seat design of the triple-offset multi-layer butterfly valve has the following characteristics.

1. Seat Installation Structure

There are two ways to install the seat of the triple-offset multi-layer butterfly valve, one is to install the seat on the disc, and the other is to install the seat on the valve body. The latter design reduces the opportunity for the seat to come into direct contact with the medium, thereby reducing the erosion of the seat and extending its service life. This design improves the durability and stability of the valve.

2. Seat Material and Structure

The seat is made of laminated stainless steel and graphite sheets, and this composite material structure effectively prevents the impact of small solid particles in the medium and the sealing surface biting caused by thermal expansion. Even in the case of minor damage, the sealing surface will not leak, which shows its unique advantages compared to other types of butterfly valves.

Maintenance and Fixing Method of Sealing Pair

 
The sealing pair design of the triple-offset multi-layer butterfly valve has the following advantages.

1. Convenient Maintenance

 
The sealing pair design of the valve allows the sealing surface of the seat body and the disc to be replaced separately. When the disc sealing surface is damaged, there is no need to send the entire valve back to the manufacturer for large-scale disassembly and repair, just replace the damaged sealing surface. This design significantly reduces maintenance costs, reduces maintenance time and inspection difficulty, and improves maintenance efficiency.

2. Fixing Method

 
The fixing method of the sealing pair adopts an elliptical distribution of bolts, which ensures that each bolt is evenly loaded, avoiding the loosening or leakage of the sealing pair caused by uneven stress distribution. The precise positioning and balanced force of the bolts improve the sealing effect, further enhancing the stability and reliability of the valve.
 
The triple-offset multi-layer butterfly valve, with its advanced design and manufacturing process, has shown significant advantages in control and shut-off applications. Its unique sealing principle, excellent economic benefits, and convenient maintenance methods make it widely applicable in high-pressure, high-temperature, and large-caliber industrial applications. Whether from the perspective of performance stability or economy, the triple-offset multi-layer butterfly valve is an ideal choice, providing a reliable solution for various industrial needs.