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To ensure the reliable operation of control valves, preventive maintenance measures can be taken during their use, including a range of preventive actions taken at the time of installation and operation on-site. These can also be referred to as routine maintenance, and are generally carried out through the following methods. 1. First, check the support and safety conditions. The optimal location for installing the control valve is such that the stroke direction of the valve stem lies in a vertical plane with the actuator located above the valve body. If the control valve must be installed in a position where the valve stem moves horizontally, or if the direction of the valve stem’s movement is at an angle to the horizontal plane, then the actuator should be supported so that all components of the control valve remain in their natural state. Moreover, the fixing and support measures for control valves must be inspected regularly. Regulating valves and related accessories used in explosive hazardous areas should have their safe operation checked, such as whether the sealing covers are tightened, the performance of the safety barriers, and the power supply status, to ensure that the regulating valves and related accessories can operate safely. 2. Remove foreign objects to prevent their entry. Regularly check the pipes connected to the control valve for rust, slag, dirt, and other contaminants; remove them promptly if found. If foreign substances tend to accumulate in the control valve and pipelines, it is necessary to consider installing a simple filtering device on the upstream side of the control valve. In situations where hard contaminants are likely to penetrate the process medium, a permanent filtration device must be installed. Because when a control valve is closed, even a small amount of rust or weld slag can damage the well-polished sealing surface of the valve seat, affecting its proper operation. 3. Conduct regular maintenance checks. In environments with a lot of dust around the air and power sources, plastic or rubber covers should be used around the valve stem to protect the stuffing box and guiding components. In areas where corrosive gases or droplets are present, special protective measures must be taken; generally, the control valve is wrapped in anti-corrosion bags, but care must be taken to ensure that this does not affect its operation. Although the diaphragm chamber of a pneumatic control valve does not consume air, if the air supply system contains impurities such as moisture and oil, it can cause blockages and malfunctions in accessories such as valve positioners and actuators. Therefore, the gas supply and power source must be checked regularly to ensure that the gas supply is clean and dry, and the power source is reliable. 4. Transportation and storage: After the control valve has been assembled and painted, and accessories such as actuators, handwheels, and positioners have been installed as required, in order to prevent foreign substances from entering the valve, all air connections to it must be sealed off. Protective covers should be placed on the connection flanges. Attention should be paid to all connection points; any protruding accessories that are prone to damage should be removed from the connections, packaged separately from the control valve, and shipped together with it. Control valves should be fixed using specialized brackets to prevent loosening, and it is necessary to ensure their overall vertical or horizontal alignment. For long-distance transportation, it is best to use sturdy wooden crates for shipping.