Electric stainless steel globe valves, as the core equipment for medium cutoff and flow regulation in industrial pipeline systems, are widely used in chemical, petroleum, power, water treatment and other fields due to their corrosion resistance, sealing and automation control capabilities. However, the reliable operation of valves relies on correct selection, standardized installation, and scientific maintenance. This article combines practical cases to systematically sort out the precautions for the use of electric stainless steel globe valves, providing a reference for enterprise lifecycle management.

1、 Selection stage: Accurately matching the working condition requirements

1. Adaptability of medium characteristics

Corrosive medium: selection should be based on the composition of the medium304/316LStainless steel material, for example, when the chloride ion content exceeds50ppmIn the working conditions, priority should be given to selecting316LMaterial to avoid pitting corrosion. A certain chemical plant selected304Material valve causes occurrence within six months3Secondary leakage, replace with316LAfter running2yearfault-free.

High temperature medium: When the temperature of the medium exceeds200℃When necessary, a hard sealing structure (such asSTLEquipped with a hard alloy sealing surface and a heat dissipating electric actuator. A certain thermal power plant caused the actuator motor to burn out due to failure to consider high-temperature heat dissipation, resulting in direct losses exceeding5Ten thousand yuan.

Medium containing particles: The sealing surface of the valve seat needs to be welded with hard alloy technology, and the valve disc is designed in a streamlined shape to reduce particle jamming. A certain mining enterprise optimized the valve disc structure to extend the service life of the valve6Extended to one month2Year.

2. Pressure rating and nominal diameter

The nominal pressure of the valve should be higher than the maximum working pressure of the system1.5Twice. for example in2.5MPaIn steam pipelines, it is necessary to usePN4.0Grade valve.

Path selection should be combined with flow calculation to avoid“Big horse pulling small car”Phenomenon. A certain water treatment project selectedDN200Valve replacement for actual needsDN150, leading to an increase in energy consumption18%.

3. Selection of electric actuators

Torque matching: The output torque of the actuator needs to be the theoretical torque of the valve1.2-1.5Twice. A petrochemical enterprise experienced a medium leakage accident due to insufficient torque causing the valve to fail to close.

Control mode: Select switch type, regulating type or intelligent actuator according to process requirements. In situations where precise flow control is required, intelligent actuators are used in conjunctionPIDAdjustment can control the error within±1%Within.

Protection level: Outdoor installation requires selectionIP65At or above the protection level, prevent rainwater from entering and causing circuit failures.

2、 Installation phase: Standardized operation to ensure performance

1. Pipeline system preparation

Cleanliness control: Before installation, it is necessary to blow the pipeline with compressed air to ensure that there are no impurities such as welding slag and rust. A semiconductor company failed to clean its pipelines properlythoroughlyCausing scratches on the sealing surface of the valve and exceeding the leakage rate5Twice.

Flange parallelism: Use a laser alignment instrument to check the flange parallelism, and any deviation should be≤0.1mm/mExceeding the standard can cause uneven stress on the sealing surface, leading to early leakage.

2. Valve installation specifications

Flow direction identification: Install strictly in the direction of the valve body arrow to avoid sealing failure caused by reverse installation. A certain paper mill installed valves in reverse,3Replace the seal within one month4Next time.

Verticality requirement: When installing vertically, the deviation of the valve stem verticality should be≤0.5°Tilting installation will accelerate valve stem wear and shorten service life.

Fixed actuator: An elastic coupling is used to connect the valve stem and actuator, absorbing installation errors. Rigid connections can easily cause valve stem bending, resulting in annual loss of valve stem for a certain enterprise12Root.

3. Key points of electrical connection

Power matching: Three phase motors need to confirm that the voltage and frequency are consistent with the power supply system, while single-phase motors need to be equipped with overload protection devices.

Grounding protection: The actuator casing must be reliably grounded, with a grounding resistance≤4ΩA chemical plant was damaged by lightning strike due to ungrounded grounding3Platform actuator.

Signal line shielding: The signal line of the regulating actuator needs to use shielded cables and be grounded at one end to prevent electromagnetic interference from causing control failure.

3、 Debugging phase: parameter optimization and functional verification

1. mechanical debugging

Travel calibration: Adjust the valve fully open through the limit switch/Fully closed position, ensure that the opening indication is consistent with the actual position. A steel plant experienced valve jamming due to travel deviation, resulting in shutdown losses exceeding20Ten thousand yuan.

Torque protection: Set the actuator stalling protection current to the rated current1.8Double, avoid overloading and burning the motor.

2. Electrical commissioning

Switch test: Conduct50The second full stroke switch test requires recording the switch time error≤0.5In seconds.

Adjustment function: Perform step response testing on adjustable actuators, with overshoot required≤10%Stable time≤5In seconds.

3. Sealing verification

Air tightness test: filled in0.6MPaNitrogen pressure maintenance5Minutes, pressure drop required≤0.02MPa.

Hydrostatic test: according to1.5Perform water pressure test at double nominal pressure and maintain pressure30No leakage in minutes.

4、 Operation and Maintenance Phase: Preventive Maintenance Strategy

1. routine inspection

Appearance inspection: Check the valve body and actuator daily for leaks and rust, and record any temperature anomalies.

Running sound: Use a stethoscope to determine if the valve stem is moving smoothly, and abnormal noise may indicate bearing wear.

2. regular maintenance

Seal replacement: every2Annual replacement of valve seat sealing ring, using imported polytetrafluoroethylene material can extend the service life to3Year.

Lubrication management: Supplement lithium based grease to valve stem threads and actuator gearboxes every quarter to reduce friction coefficient30%The above.

Electrical testing: Measure the insulation resistance of the motor with a megohmmeter every year（≥1MΩ）Check the tightness of the wiring terminals.

3. Fault handling

Leakage handling:

Leakage: tighten flange bolts or replace gaskets;

Internal leakage: Grind the sealing surface of the valve disc or replace the valve seat.

Actuator malfunction:

Motor not turning: Check the power supply, fuses, and overload protection device;

Position deviation: recalibrate the travel switch or replace the encoder.

5、 Typical Case Analysis

case1Control of Valve Internal Leakage in Chemical Enterprises
The electric stainless steel globe valve of a certain chlor alkali factory is in operation1Internal leakage occurred after the year, and upon testing, it was found that:

Reason: In the mediumCl⁻Excessive content leads to304Material valve seat pitting corrosion;

Measure: Replace with316LMaterial valve seat and optimized process parameters;

Effect: Leakage rate from0.5%drop to0.02%Annual savings in media costs12Ten thousand yuan.

case2Prevention of actuator failures in the power industry
A certain thermal power plant has reduced the actuator failure rate by implementing the following measures75%：

Establish a temperature monitoring system, when the actuator temperature exceeds85℃Automatic alarm upon arrival;

Clean the dust on the heat sink every quarter to ensure smooth ventilation;

Reserve key spare parts (such as encoders and capacitors) and increase the average repair time from8Shorten hours to2Hour.

Conclusion

The reliable operation of electric stainless steel globe valves is a comprehensive reflection of selection accuracy, installation standardization, scientific debugging, and preventive maintenance. Enterprises need to establish a full lifecycle management system to achieve equipment efficiency through technical training, spare parts management, and digital monitoringmaximizeAccording to statistics, standardized operation and maintenance can extend the service life of valves40%Above, the annual maintenance cost has been reduced30%Create significant economic benefits for enterprises.