Common Faults of Electric Single-Seat Control Valves

 
Electric single-seat control valves play a crucial role in modern automation control systems, capable of precisely regulating fluid flow to ensure system stability and efficiency. To ensure the proper operation of this vital equipment, it is essential to understand its core components and common faults. This article will provide a detailed analysis of the components of the electric single-seat control valve and discuss common faults encountered during operation, along with their symptoms and remedial measures, offering practical guidance for equipment maintenance and optimization.

Basic Components

 
The efficient operation of the electric single-seat control valve relies on its precise design and structure, where each component plays a significant role in ensuring the valve's precise control and reliability. Below, we will introduce the core components of the electric single-seat control valve, including the onboard electronics (OBE), coil, spool, and valve shaft. These parts work in concert to achieve accurate regulation and control of fluid flow.

1. Onboard Electronics

 
The onboard electronics (OBE) is the central control component of the electric single-seat control valve. It typically includes an amplifier circuit board responsible for receiving and processing incoming current signals. OBE converts direct current into a driving signal for the coil, thereby transforming electrical energy into mechanical work. This process enables the electric signal to drive various components of the valve for precise control of fluid flow. The design and stability of the OBE directly affect the control accuracy of the valve and the overall performance of the system.

2. Coil

 
The coil is a vital component of the electric single-seat control valve, consisting of a pair of permanent magnets and a wound coil. When current flows through the coil, it generates a magnetic field that produces torque. This torque drives the mechanical movement of the valve, regulating fluid flow. The design of the coil determines the valve's response speed and control accuracy, and the quality of the coil directly affects the valve's stability and long-term reliability.

3. Spool

 
The spool is a component driven by the coil, and its position changes affect the fluid pressure between two nozzles. By adjusting the position of the spool, the pressure difference of the fluid is changed, causing the valve core to move. The movement of the valve core determines the direction and quantity of fluid flow, thereby controlling the working state of the hydraulic actuator. The design and operational status of the spool directly affect the valve's flow control accuracy and stability.

4. Valve Shaft

 
The valve shaft is the central axis of the electric single-seat control valve, and its precision determines the flow direction of the fluid within the valve. The valve shaft is usually processed with high precision to ensure that the fluid flows in the intended direction. The quality of the valve shaft's machining directly affects the valve's sealing performance and the smoothness of fluid flow.

Common Faults and Symptoms

 
During the use of electric single-seat control valves, various faults may be encountered that can affect the valve's performance and system stability. Understanding the symptoms and causes of these common faults helps to identify and resolve issues early, ensuring the normal operation of the valve. Here are some typical fault types and their corresponding symptoms and solutions.

1. Complete System Failure

 
Symptoms: The valve has no flow or cannot switch.
Cause: The main cause may be overcurrent of the amplifier board or overload at the output end, leading to overheating of the coil winding. In this case, the valve usually needs a coil replacement. Other possible causes include mechanical blockage of the valve core within the valve body, which may be caused by poor fluid quality, wear, or manufacturing defects. Thermal expansion caused by extreme temperatures may also interfere with the position of the valve core.
Solution: Regularly inspect and replace coils, clean or replace filters, and check for mechanical blockage of the valve core. Ensure that the system operates within the appropriate temperature range to avoid the impact of extreme conditions on the valve.

2. Performance Degradation

 
Symptoms: The valve operates slowly or with resistance.
Cause: The sliding and variable speed components of the electric single-seat control valve may experience performance degradation due to wear. The centering spring may also lose its tension over time, affecting the position of the valve core. Seal failure due to aging, heat, or contamination can also lead to pressure loss, electronic equipment contamination, or mechanical component wear.
Solution: Regularly inspect the condition of sliding parts and springs, and rebuild or replace them when necessary. Regularly replace seals, clean and maintain electronic equipment to ensure its normal operation.

3. OBE Failure

 
Symptoms: Unstable control signals or abnormal valve response.
Cause: OBE components may fail due to heat, noise, electrical load issues, or contamination. Common failing components include capacitors, diodes, and resistors, which may fail due to overheating or contamination.
Solution: Regularly check the operational status of OBE components to ensure they are functioning properly. Clean hydraulic fluids that may cause contamination and prevent electronic equipment failures due to poor maintenance.

4. Actuator's Oscillating Motion

 
Symptoms: Unstable valve operation with oscillation.
Cause: Oscillation may be caused by weak coils, intermittent electrical connections, or erroneous feedback signals from the control part. Dirtiness or blockage of the filter screen, valve core housing, or nozzle contamination can also cause oscillation. Additionally, the condition of the hydraulic oil greatly affects oscillation; oil that is too cold or too hot can affect its viscosity, leading to mechanical wear on the valve.
Solution: Check coils and electrical connections to ensure they are functioning properly. Clean filter screens and check for contamination on valve cores and nozzles. Ensure hydraulic oil is within the appropriate temperature range and use the fluid type recommended by the manufacturer.
 
Understanding the components and potential faults of the electric single-seat control valve not only helps maintenance personnel to identify and resolve issues promptly but also significantly enhances the system's operational efficiency and reliability. Regular inspection, maintenance, and proper fault handling ensure the valve operates stably under various operating conditions, thus ensuring the smooth and efficient operation of the entire control system. Mastering this foundational knowledge will help extend equipment life, reduce downtime, and improve the overall performance of the system.