Gate valve

Electric switch type and regulating type intelligent rising stem knife gate valves are the core control equipment in modern industrial pipeline systems. There are significant differences between the two in functional positioning, structural design, and applicable scenarios, which can meet the precise control requirements of different working conditions.

1、 Electric switch type rising stem knife gate valve
Structural characteristics: Adopting a rising stem design, the valve stem thread is exposed, and the valve stem is driven vertically up and down by an electric actuator, which drives the wedge-shaped gate to achieve full opening or full closing of the pipeline. A hard seal or elastic seal structure is used between the gate and the valve seat to ensure zero leakage under high pressure difference.  
Control mode: The actuator is equipped with a built-in limit switch, which receives a switch signal (such as 24VDC or 220VAC) and performs a fast opening and closing action. The action time is usually 10-30 seconds, suitable for binary control scenarios that do not require flow regulation.  
Intelligent functions: Integrated valve position feedback (4-20mA or dry contact signal), overload protection, and fault self diagnosis system, supporting Modbus, HART and other protocols for remote status monitoring, and can trigger ESD emergency shutdown in case of abnormalities.  
Typical applications: municipal water supply and drainage pump station cut-off, emergency cut-off of oil storage tanks, and isolation of ash and slag systems in thermal power plants.

2、 Electric adjustable rising stem knife gate valve
Core upgrade: Install high-precision servo motor and position positioning module on the basis of switch type, equipped with pressure/flow sensors to form a closed-loop control system, and the valve stem stroke can achieve 0-100% stepless adjustment.  
Control accuracy: Receive analog signals (4-20mA) or bus commands (Profibus DP), adjust the opening in real time through PID algorithm, with an adjustment accuracy of ± 1% FS and a response time of ≤ 1 second, suitable for dynamic flow control.  
Structural optimization: The gate adopts a V-shaped port design, and the flow characteristic curve is adjustable (linear/equal percentage). The valve seat is welded with Stellite alloy, which is resistant to particle media erosion and suitable for two-phase flow media such as slurry and coal powder.  
Intelligent expansion: It has the functions of data recording and predictive maintenance, analyzes the change of valve torque curve through edge computing, alerts the jam risk in advance, and supports OPC UA access to the industrial Internet of Things platform.  

3、 Selection comparison dimension
-Control requirements: The switch type is suitable for safety isolation, while the regulating type is used for process control (such as adjusting the feed ratio of chemical reaction vessels).  
-Medium characteristics: The regulating type needs to consider Cv value calculation and flash/cavitation protection, while the switch type pays more attention to sealing level (such as ANSI Class VI).  
-Cost composition: The price of the adjustable type is about 40% higher, as it requires a precision locator and an anti vibration electrical interface (IP68/NEMA 4X).  

Both types of valves comply with API 6D and ISO 5208 standards, and their intelligent products have passed SIL2 certification. They are widely used in fields such as smart water management and smart oil fields, promoting process automation upgrades in the Industry 4.0 process.