Slow Closing Check Valve with Position Feedback

Slow closing check valve with position feedback is a high-performance one-way protection valve specially designed for pump outlet pipelines, combining hydraulic slow-closing buffer function and electric signal position monitoring module. It effectively eliminates destructive water hammer shock caused by sudden pump shutdown, while feeding real-time valve opening and closing status back to central control systems, realizing visual remote monitoring and interlock linkage. Compared with ordinary swing check valves that snap shut instantly, this product avoids pipeline rupture, flange leakage and pump impeller damage triggered by reverse water impact, making it a standard safety accessory for municipal water supply, sewage treatment, hydropower stations and industrial circulating water systems.

Its core slow-closing mechanism adopts two-stage hydraulic damping control. When the water pump operates normally, fluid thrust pushes the valve clack fully open to form a straight-through low-resistance flow channel. Once the pump stops unexpectedly, medium reverses instantly. In the first stage, the valve clack quickly rotates to 70% closed position to cut most reverse flow; in the second stage, built-in adjustable hydraulic cylinder provides damping resistance to slow down the remaining closing stroke within a preset time range of 3 to 60 seconds. The adjustable buffer stroke greatly reduces reverse flow velocity and instantaneous pressure surge, fundamentally restraining positive and negative water hammer waves inside the pipe network. The damping oil chamber is equipped with independent flow regulating screws, allowing on-site staff to adjust closing speed according to pipeline diameter, water flow rate and actual pressure conditions without disassembling the valve body.

The unique position feedback assembly is mounted on the valve spindle extension end, consisting of a precision angular displacement sensor and limit micro switches. The sensor converts the real-time swing angle of the valve clack into standard 4-20mA analog signals, transmitting continuous opening degree data to PLC, DCS or remote monitoring platforms. Two sets of mechanical limit switches separately output digital on-off signals to indicate full-open and full-closed states. Operators in the control room can clearly grasp the working status of each check valve at all times. When abnormal jamming or incomplete closing occurs, the system immediately triggers alarm signals to remind maintenance personnel to troubleshoot hidden pipeline risks in advance.

The main valve body is integrally cast from ductile iron EN-GJS-500-7 or carbon steel WCB as optional. Inner and outer fusion-bonded epoxy coating above 250 μm delivers outstanding anti-rust and anti-scaling performance, complying with drinking water sanitary standards. The valve clack sealing surface uses vulcanized EPDM soft rubber to achieve zero leakage under PN10, PN16 and PN25 pressure grades. The spindle adopts solid stainless steel with multi-layer composite sealing rings, which can be replaced online without pipeline shutdown. Flanged connection conforms to GB and DIN standards, covering specifications DN50 to DN1600 to match small branch pipes and large-diameter main transmission pipelines. Applicable media include tap water, fire water, river raw water, industrial circulating water and lightly corrosive wastewater, with working temperature ranging from 0℃ to 80℃. Every product undergoes shell strength testing at 1.5 times nominal pressure and tightness inspection before factory delivery.

This valve integrates safety protection and intelligent monitoring into one unit, solving two major pain points of traditional check valves: severe water hammer impact and invisible working state. It is widely installed at pump outlets in urban water plants, reservoir delivery pump rooms, large irrigation pumping stations and chemical water circulation workshops. By stabilizing pipe network pressure, protecting pumps and pipe fittings, and supporting automatic centralized management, it lowers equipment failure rates, cuts maintenance costs and improves the overall safety and automation level of fluid transportation systems.