For large pumping stations, water conservancy and municipal water supply infrastructure projects, water hammer surge protection, emergency power failure safety and pipeline space optimization are core evaluation criteria for EPC contractors and design institutes during large-diameter pipeline equipment selection. The DN1000, PN16 welded hydraulic butterfly valve fitted with counterweight slow-closing oil cylinder and S355J steel valve body is widely adopted as a reliable solution for pump outlet pipeline systems.

Fabricated from S355J low-alloy structural steel, the valve body delivers remarkable low-temperature impact toughness and outstanding weldability compared with conventional cast iron alternatives. It can operate stably under PN16 pressure rating in harsh environments including open-air sites and low-temperature regions. The integrally welded structure features superior rigidity and deformation resistance over traditional cast flanged valve bodies, which is especially critical for ultra-large DN1000 nominal bore size.

This valve adopts a combined configuration of counterweight energy storage and hydraulic slow-closing cylinder. The hydraulic actuator opens the valve and lifts the counterweight to store gravitational potential energy simultaneously. In emergency conditions such as power outage or system pressure loss, the stored potential energy of the counterweight drives the valve to close automatically. Together with the buffer oil cylinder, it achieves adjustable two-stage closing sequence: rapid pre-closing followed by slow final sealing. This mechanism effectively suppresses water hammer pressure spikes generated during pump shutdown and prevents structural damage to pipelines and pump assemblies.

It integrates the functions of isolation valve and non-return check valve. One single unit can replace the conventional combination of gate valve plus check valve, which greatly simplifies pipeline arrangement, cuts civil construction investment, on-site installation workload and long-term maintenance expenditure. Equipped with mechanical limit devices and position feedback sensors, the valve is compatible with PLC automatic control systems and supports local manual operation as well as remote interlock control. It is suitable for automated pumping stations, hydropower plants, municipal water distribution, seawater desalination and other fluid transportation facilities.

Conventional large-bore valves have prominent limitations: uncontrollable closing speed, lack of passive protection when power fails, and insufficient structural strength for oversized valve bodies. This welded hydraulic counterweight slow-closing butterfly valve with S355J body solves these common pain points via optimized material specification, mature driving mechanism and reliable control logic. It maintains a low flow resistance coefficient, stable sealing performance and low failure rate during long-term continuous service. It has become a standard specification in global water conservancy and water supply construction projects. Customized opening & closing timing, anti-corrosion coating and matched hydraulic control packages are available according to actual site operating conditions.

For international engineering buyers, S355J structural steel conforms to European material standards, which facilitates material inspection and project acceptance for overseas projects in Europe, Southeast Asia, the Middle East and other regions. The buffer cylinder allows on-site fine-tuning of slow-closing angle and duration. Engineers can precisely calibrate water hammer suppression performance based on actual pipeline length, flow velocity and medium characteristics.

Apart from clean water medium, the valve can be upgraded to process raw water with slight sediment and low-concentration seawater with special surface anti-corrosion treatments. The auxiliary hydraulic unit is compact and user-friendly for routine maintenance; spare parts for oil cylinder and counterweight assembly are globally accessible to support local after-sales service.Compared with alternative water hammer mitigation equipment such as surge tanks and air vessels, this all-in-one valve solution reduces overall project budget and occupies less space inside pump buildings, which is a key advantage for projects with limited room layout.