Structural features

1. Valve body structure: Super-large pressure resistance and flow optimization
The valve body is made by thick-walled integral casting process, using high-strength ductile iron QT500-7 (suitable for general industrial and municipal water supply) or carbon steel WCB (capable of withstanding higher pressure and non-corrosive media). For some parts used in highly corrosive environments, stainless steel 316L is welded into shape. The wall thickness is increased by 40% to 50% compared to the conventional diameter based on the pressure rating (such as PN10, PN16). Through finite element analysis, the valve body structure is comprehensively optimized to effectively resist the deformation risk caused by medium pressure under the super-large diameter of DN2500. ​
The flow channel is designed as an equal straight-through streamlined type, with an inner diameter strictly adhering to the nominal size of DN2500. The inner wall of the flow channel is treated with high-precision polishing, with a roughness Ra≤0.8μm, which greatly reduces the flow resistance of the medium (such as large-scale urban water supply and material transportation in large chemical industrial parks), ensuring efficient and stable transportation even under ultra-high flow conditions. ​
2. Butterfly Plate and Seal: Over-specification sealing guarantee
Butterfly plate: It adopts a three-eccentric structure, which is a key design for large-diameter butterfly valves to ensure sealing performance. The material is made of high-strength alloys, such as stainless steel 316L with a tungsten carbide hard alloy coating, to enhance wear resistance and corrosion resistance. The thickness of the butterfly plate is further increased by 20% to 30% compared with the DN1200 and DN1600 models. Through advanced finite element analysis, its force-bearing structure is precisely optimized to ensure that the butterfly plate always maintains good rigidity and no warping deformation during frequent opening and closing processes. The edge of the butterfly plate is precisely turned and ground, and the fit error with the sealing surface is controlled within ≤0.05mm. When closed, it can strictly meet the API 598 VI grade zero leakage standard, and is suitable for occasions with extremely high sealing requirements. ​
Sealing surface: The soft seal adopts specially designed embedded ethylene propylene diene monomer (EPDM) or fluorine rubber (FKM). The rubber cross-section is innovatively designed as "Ω shape", which can provide a stronger extrusion sealing effect under large diameters compared with the traditional "U shape". The hard seal adopts stainless steel surfacing cobalt-based hard alloy (Stellite 21) or advanced ceramic coating (ZrO₂), and the sealing surface width is expanded to 20-25mm, significantly enhancing the wear resistance and erosion resistance of the sealing surface. It can operate stably within an ultra-wide temperature range of -50 ℃ to 600℃ and in various complex and corrosive medium environments. ​
3. Valve stem and drive: Suitable for power transmission under extremely large loads
Valve stem: It adopts an ultra-thick solid multi-support structure. The top is closely connected to the drive device, and the bottom is fixed by at least two sets of high-precision bearings, ensuring that under the huge self-weight of the DN2500 butterfly plate and the impact of medium pressure, the valve stem can still maintain a precise rotational axis without bending or shifting. The valve stem material is selected from 2Cr13 stainless steel (for conventional environments) or the more corrosion-resistant 316L stainless steel based on the working conditions. The diameter is increased by more than 30% compared to the DN1600 model (for example, φ50mm is used for DN1600, and φ65mm or more may be used for DN2500). The surface undergoes nitriding treatment. Hardness HV≥1000 effectively enhances the wear resistance and fatigue resistance of the valve stem. ​
Drive adaptation: Given the huge operating torque of the DN2500 butterfly valve, it mainly adopts electric (high-power multi-turn motor) or pneumatic (large-diameter double-acting cylinder) drive, and is equipped with a high-precision, high-speed-ratio reducer and intelligent torque limiter. The opening and closing process is slow and smooth, with an opening and closing time usually ≥60 seconds, effectively avoiding the damage caused by water hammer to the pipeline system. Electric drive can be integrated with an advanced intelligent control system, supporting remote monitoring, fault diagnosis, real-time torque monitoring and protection, ensuring that the valve can operate safely and stably even when unattended. Manual drive is only used as an emergency backup. It is equipped with a super-large speed ratio worm gear mechanism, which significantly reduces the operating force of the operator, but the actual operation frequency is relatively low. ​
4. Flange connection: Guarantee for the connection of super-large pipes
Strictly follow the national standard GB/T 9119-2020 or the American standard ANSI B16.5. Heavy-duty flanges are selected, and the sealing surface of the flange adopts tenon groove surface (TG) or trapezoidal groove surface (RTJ) with excellent sealing performance. The number of bolt holes has been significantly increased to 36-48, and the hole diameters have been further enlarged (for example, from φ27mm of DN1600 to φ30mm and above), which is suitable for high-strength and high-grade bolts (such as 10.9 grade or 12.9 grade alloy steel bolts), ensuring that under ultra-large diameter and high-pressure working conditions, The flange connection part always remains free of leakage. ​
The flange end face is precisely processed, with a parallelism error of no more than 0.03mm/m, facilitating precise and efficient connection with the pipe flange. When installing, it is paired with specially made metal wound gaskets (with reinforced inner rings) or expanded graphite composite gaskets to further enhance the sealing reliability and effectively prevent medium leakage. ​
5. Auxiliary structure: Special reinforcement for super-large valves
8 to 12 high-strength reinforcing plates are evenly added along the circumference of the flange on both sides of the valve body, significantly enhancing the structural strength of the connection between the valve body and the flange. This effectively prevents the flange from deforming due to the huge preload during the process of tightening the installation bolts, ensuring the stability of the overall structure of the valve. ​
The bottom of the valve stem is carefully equipped with a large-diameter drain valve (DN40-DN50), which can regularly and conveniently discharge the medium remaining in the valve stem sealing cavity, prevent the long-term accumulation of the medium from causing corrosion to the valve stem, and extend the overall service life of the valve stem and the valve. Some high-end models are equipped with high-precision pressure detection interfaces (G3/4 thread) on the top of the valve body, facilitating real-time and accurate monitoring of pressure changes inside the valve. This provides key data support for the long-term stable operation and maintenance of the valve, fully meeting the long-term and reliable operation requirements of DN2500 large-diameter valves under complex working conditions. ​