Electric Gate Valve Industry Knowledge
1. Basic Introduction
An electric gate valve is one of the most essential on‑off valves in industrial fluid‑control systems. It is assembled by a gate‑valve body and an electric actuator. Driven by the torque output from the electric actuator, the valve stem lifts or lowers the gate disc vertically to open or shut off the pipeline flow.
The sample shown in the picture is marked DN200‑PN16. DN200 means its nominal bore is 200 mm, and PN16 stands for nominal pressure 1.6MPa (16 bar). It is a widely‑used medium‑large‑size industrial electric gate valve.
Working principle: The gate disc is placed perpendicular to the flow direction. When the gate disc is fully lifted, the inner passage is completely open, and the medium flows straight through with little resistance. When the gate disc falls down and seals against the valve seat, the pipeline is fully closed.
Gate valves are designed for full‑open or full‑close operation only. Throttling is forbidden. If the gate disc stays half‑open for flow regulation, high‑speed fluid will wash and erode the sealing surface, quickly resulting in internal leakage, seal damage and shortened service life.
2. Main Components
(1) Electric Actuator
The blue driving device installed on the top of the valve body is the power‑control unit of the electric gate valve. It consists of a drive motor, reduction gearbox, travel limit switches, torque‑protection device, local control push‑buttons and a digital display screen.
Operators can control valve opening and closing locally on‑site, or remotely from the central control room via 4‑20mA analog signals or digital on‑off signals. Built‑in overload protection will cut off power automatically once the operating torque exceeds the safety setting, protecting the motor and valve stem from breakage.
Intelligent actuators support real‑time data feedback, fault alarm and industrial communication, transmitting valve position, running status and error codes to the control system, which perfectly meets the demands of smart factories and unattended pumping stations.
(2) Gate‑Valve Body
This is an outside‑screw‑and‑yoke (OS&Y) cast‑steel gate valve. Its valve stem extends outwards when the valve opens. Operators can directly observe the stem extension length to judge the real‑time opening status.
Flange connections on both sides are bolted to industrial pipelines, bringing convenient installation, maintenance and reliable sealing performance. Internal parts contain valve seats, gate disc and stem packing, which prevents medium leakage along the valve‑stem gap.
3. Key Advantages
Low flow resistance: Straight‑through passage creates minimum pressure loss, ideal for large‑flow long‑distance pipelines.
Labour‑saving operation: Electric power provides high‑output torque, eliminating heavy manual work especially for large‑bore valves such as DN200.
Remote automatic control: Compatible with DCS central control systems. Remote operation avoids safety hazards caused by manual field‑work under high‑temperature or toxic conditions.
Bi‑directional shut‑off performance: The valve can cut‑off flow from both directions. No specific flow direction requirement during on‑site installation.
4. Application Fields
Electric gate valves are suitable for water, wastewater, circulating water, steam, hot water, diesel oil, lubricating oil and non‑corrosive gas.
Major application industries:
‑ Municipal water supply & drainage, waterworks, sewage‑treatment plants;
‑ Central‑heating pipelines and boiler stations;
‑ Power plant circulating‑water systems;
‑ Petrochemical, metallurgy and mining industries;
‑ Heating‑ventilation systems for industrial parks and large buildings.
5. Selection & Maintenance Guidelines
Temperature matching: Use standard cast‑steel bodies for normal‑temperature water. High‑temperature steam service requires heat‑resistant packing and components.
Pressure rating: The maximum working pressure of pipelines cannot exceed the PN16 rated pressure.
Signal confirmation: Confirm control signal types (on‑off signal or 4‑20mA modulating signal) before ordering the actuator.
Routine inspection: Check wiring connections, lubricate the valve stem regularly and verify travel limits annually to prevent leakage.
No‑throttling rule: Install separate control valves if flow regulation is required, do not use gate valves for throttling.
