PTD643H Triple Eccentric Hard Seal Butterfly Valve

Zhejiang Putian triple eccentric butterfly valves can be selected for applications involving two-position regulation, constricted underground channels, low noise, cavitation and vaporization phenomena, minor atmospheric leakage, and abrasive media.

For throttling regulation under special working conditions, or where strict sealing is required, or in severe wear, low-temperature (cryogenic) and other demanding conditions, specially designed triple or double eccentric butterfly valves with metal sealing and regulation devices must be used.

Zhejiang Putian triple eccentric butterfly valves are suitable for applications requiring complete sealing, zero gas test leakage, high service life, and operating temperatures between -10°C and 150°C. They are used in freshwater, sewage, seawater, saline water, steam, natural gas, food, oil, various acids and alkalis, and other pipelines.

Zhejiang Putian soft-seal eccentric butterfly valves are suitable for bidirectional opening/closing and regulation in ventilation and dust removal pipelines, widely used in gas pipelines and water channels in metallurgical, light industry, electric power, and petrochemical systems.

Zhejiang Putian triple eccentric metal-to-metal line seal double eccentric butterfly valves are suitable for urban heating, gas supply, water supply, and other pipelines carrying gas, oil, acids, alkalis, etc., serving as regulation and throttling devices.

Zhejiang Putian triple eccentric metal-to-metal face seal triple eccentric butterfly valves, in addition to being used as program control valves in large pressure swing adsorption (PSA) gas separation units, are also widely applicable in petroleum, petrochemical, chemical, metallurgical, and electric power industries.

Working principle of Zhejiang Putian triple eccentric metal hard seal butterfly valve: In a typical triple eccentric metal seal butterfly valve, besides the two eccentrics of the valve stem and disc, the sealing surfaces of the disc and seat are conical (the third so-called eccentricity). When the valve closes, the disc is pushed forward due to eccentricity, avoiding friction between the disc and seat during closure. The disc directly presses against the seat, ensuring long service life.

Additionally, because the sealing ring (whether mounted on the seat or disc) has certain elasticity and a small gap between the boss and the elastic ring allowing slight displacement, under closing force, the elastic seal ring automatically moves to a uniformly stressed position. Combined with minor deformation of the elastic ring, the seal achieves even force distribution and effective sealing.

Performance variations of triple eccentric metal hard seal butterfly valves with different eccentric structures: Traditionally, butterfly valves were considered suitable only for常温, low-pressure, and less critical sealing applications.

With advancements in modern technology and materials, Zhejiang Putian butterfly valves now have a much broader application range, nearly replacing most traditional valves and widely used across various industries. Triple eccentric metal seal butterfly valves are particularly noteworthy.

Since the closure of triple eccentric butterfly valves, like gate valves, is torque-based, higher closing torque results in better seat sealing. Hence, they are sometimes called 90-degree rotating gate valves. In major plant overhauls, triple eccentric butterfly valves increasingly replace gate valves. Some manufacturers produce triple eccentric butterfly valves with the same face-to-face dimensions as gate valves, dubbing them triple eccentric gate valves.

As the number of eccentrics increases in Zhejiang Putian valves, the disc thickness also increases, raising fluid flow resistance. Performance changes significantly with the number of eccentrics.

Comparison of four different butterfly valve structures shows that triple eccentric valves can generate substantial pressure drop, making them suitable as control valves. Pressure drop across the valve increases with the number of eccentrics, but compared to some non-butterfly valves, it remains relatively low. Seat sealing performance also changes with eccentricity; triple eccentric valves offer superior sealing. Increased eccentricity reduces the torque required for operation, making triple eccentric valves much easier to operate than other types.

With varying eccentricity, the temperature-pressure rating and applicable temperature range of butterfly valves change considerably. Triple eccentric valves have the broadest range of applicable temperatures and pressure ratings among butterfly valve types.

Advantages of triple eccentric butterfly valves: Excellent shut-off performance. Triple eccentric metal seal butterfly valves use torque to achieve shut-off, providing outstanding seat sealing, often referred to as zero leakage valves. Solid particles or contaminants in the medium have minimal impact on shut-off performance because high flow velocity near closure prevents accumulation on the seat.

Features of metal hard seal butterfly valves:

1. Zhejiang Putian triple eccentric multi-layer metal hard seal butterfly valves have disc seals made of laminated soft and hard metal sheets, combining the advantages of metal and elastic seals. They offer excellent sealing performance at both low and high temperatures.

2. Bushings installed at the upper and lower parts of the valve stem minimize wear and friction, preventing wear and sticking while enhancing service life.

3. The three-dimensional eccentric structure ensures almost no friction between the seat and disc, minimizing internal part damage during closure. This structure significantly improves valve performance and provides a tighter seal with increased closing force.

4. The valve body sealing surface is overlay welded with alloy steel or Stellite hard alloy, offering wear, erosion, and corrosion resistance, resulting in a long service life.

5. Compact structure with low operating torque, flexible, labor-saving, and convenient operation, unaffected by medium pressure. Reliable sealing performance, suitable for both shut-off and regulation.

Eccentricity 1: The valve shaft is located behind the seat axis, enabling complete and tight sealing contact around the entire seat.

Eccentricity 2: The valve shaft centerline is offset from the pipeline and valve centerline, avoiding interference during valve opening and closing.

Eccentricity 3: The seat cone axis is offset from the valve shaft centerline, eliminating friction during opening and closing and achieving uniform compression sealing around the entire seat.