Discussion on instrument maintenance procedures

Maintenance and Repair Procedures for Electromagnetic Flow Meters 1 General Provisions 1.1 Subject Matter and Scope of Application These procedures specify the specific technical requirements and implementation steps for the maintenance, repair, commissioning of electromagnetic flow meters, as well as the safety precautions to be observed. 1.2 Basic working principle: This instrument operates on the principle of electromagnetic induction. 1.3 Composition and Function: This instrument is mainly composed of a sensor and a converter. The sensor converts the liquid flow rate signal into an induced electromotive force that has a certain functional relationship with it. The converter converts the potential signal (mV) from the sensor into a standard 4–20 mA DC signal, and the digital panel displays the flow rate value. 1.4 Main Technical Performance and Specifications 1.4.1 Performance Indicators Basic error: ±0.5% 1.4.2 Basic Requirements for Maintenance Personnel Maintenance personnel should meet the following requirements: a. Be familiar with these procedures as well as relevant technical documents such as the product manuals ； b. Understand the process flow and the role of this instrument within it ； c. Master the basic theoretical knowledge in areas such as fundamental electrical engineering, fundamental electronic engineering, chemical process measurement instruments, and maintenance ； d. Master the basic skills for the maintenance, repair, commissioning of this instrument, as well as the handling of common faults ； e. Master the usage of common measuring instruments and relevant standard instruments. 2 Intact conditions 2.1 The components are complete and meet the technical requirements, that is: a. The components should be clear and error-free ； b. The components should be in good condition, complete, and standardized ； c. Fasteners must not be loose ； d. The connectors should make good contact ； e. The terminal connections should be secure ； f. The adjustable parts should be in the adjustable position ； g. The seals should be leak-free. h. The protective and insulation facilities provided should be in good condition. 2.2 It operates normally and meets the usage requirements, that is: a. During operation, the instrument should achieve the specified performance indicators ； b. Under normal operating conditions, the instrument reading should be above 1/3 of the full scale. 2.3 The equipment and the surrounding area should be neat, clean, and meet the requirements for working conditions; that is: a. The entire unit should be clean, free from rust, with a smooth and shiny paint finish, and without any peeling paint ； b. The scales should be clear, and the markings should be neat ； c. The instrument wiring is neatly laid out ； d. The line numbers should be complete, clear, and accurate. 2.4 The technical documents are complete, accurate, and meet the management requirements, namely: a. The instruction manuals, certificates of conformity, and inspection certificates upon arrival at the factory must be available ； b. Operation records, fault handling records, maintenance records, calibration records, and parts replacement records must be accurate and error-free ； c. The system schematic diagram and wiring diagram should be complete ； d. The instrument constants and records of any changes to them should be complete. 3 Maintenance 3.1 Routine Maintenance 3.1.1 Patrol Inspections At least two patrol inspections shall be carried out per shift, covering the following: a. Inquiring with the process personnel on duty about the operation status of the instruments ； b. Check whether the instrument readings are normal ； c. Check whether the power supply to the instrument is normal ； d. Check whether there are any leaks, damages, or corrosion in the table body (connection pipes and circuits) ； e. Any issues identified should be addressed promptly, and records of routine inspections should be kept. 3.1.2 Regular maintenance The contents of regular maintenance include: a. Keeping records of operational conditions at the end of each shift ； b. Clean the instruments once a week ； c. Conduct a damping check on the instrument operation status once a month ； d. Adjust the instrument zero point every 3 months ； e. Clean the sensor electrodes every 6 months. 3.2 Faults and Troubleshooting 3.2.1 Indication of over-range in the negative direction Causes: a. Open circuit in the loop, loose terminals, or power supply interruption; b. No medium to be measured in the measurement pipeline; c. Electrodes covered by insulating materials. Solutions: a. Check the wiring terminals and power supply; b. Verify whether there is medium in the pipeline and fill it with the process medium; c. Clean the electrodes. 3.2.2 Appearance of spikes in the indication Causes: a. Presence of highly conductive substances in the liquid; b. Increase in damping time. Solutions: a. Increase the damping time; b. Clean the electrodes. 3.2.3 Irregular changes in the indication Causes: a. Electrodes completely insulated; b. Large fluctuations in liquid flow rate; c. Leakage of liquid from the electrodes, causing the detector to become damp and reducing the insulation between the electrodes and ground. Solutions: a. Clean the electrodes; b. Increase the damping time; c. Disassemble and clean the electrodes, ensuring they are dry. 3 Maintenance 3.1 Maintenance schedule This instrument should be maintained every 12 months, usually in conjunction with the factory’s annual maintenance routine. 3.2 Maintenance Tasks 3.2.1 Removing dust from inside the converter ； 3.2.2 Check the contact condition of each connector to ensure reliable contact. 3.2.3 Clean the sensor electrodes. 3.2.4 The instruments after maintenance shall be calibrated in accordance with the **Measurement Calibration Regulations. 3.3 Maintenance Quality Standards The instruments after maintenance shall meet the satisfactory conditions specified in Chapter 2. 4 Commissioning 4.1 Preparatory work before commissioning 4.1.1 Check whether the power supply for the instruments is normal. 4.1.2 Check whether the instrument wiring is correct and secure. 4.1.3 Check whether the setting parameters of each instrument are accurate. 4.2 Commissioning Steps 4.2.1 Connect the external power supply to the instrument. 4.2.2 Turn on the power switch of the instrument to allow it to warm up for 15 minutes. 4.2.3 When the pipe is filled with stationary liquid, the flow rate should display zero, and the output current will be 4 mA. 4.2.4 If the flow rate display shows large fluctuations, adjust the time constant to stabilize it. 4.3 Verification 4.3.1 Check the completion of each maintenance item one by one. 4.3.2 Check whether the instruments meet the maintenance quality standards. 4.3.3 After the instrument has been operating normally for 72 hours, it shall be signed for by the relevant technical supervisor. 5 Safety Precautions 5.1 Precautions for Maintenance 5.1.1 Maintenance must be carried out by at least two persons. 5.1.2 For operations that may cause fluctuations in process parameters, prior approval from process engineers must be obtained. 5.1.3 After repairing the sensor, lock the gauge cover to prevent the instrument from getting damp. 5.2 Safety Precautions for Maintenance 5.2.1 A work order must be obtained for the maintenance of operating instruments. 5.2.2 Instruments and components must not be removed while energized. 5.2.3 Inappropriate tools must not be used for maintenance to prevent damage to the instruments. 5.2.4 Non-standard and substandard components shall not be used. 5.2.5 When cleaning instrument components and printed circuit boards, appropriate cleaning agents must be used. 5.2.6 Before removing the sensor, the pressure should first be released. 5.3 Precautions for Safe Commissioning 5.3.1 At least two persons must be involved in the operation prior to commissioning. 5.3.2 Before commissioning, contact the process engineers and obtain their assistance and cooperation. 5.3.3 After the instruments are put into operation, their performance and the changes in related process parameters must be closely monitored. Only after it is confirmed that the instruments are operating properly can it be considered that the installation is complete.

The maintenance tasks are not clear, making it even more difficult to follow the procedures

\"Equipment Maintenance and Repair Procedures, Volume 4: Instruments and Meters\", and \"Petroleum and Chemical Industry Equipment Maintenance and Repair Procedures, Volume 7: Instruments\" – quite comprehensive.

Sure, please send over the instrument inspection system and forms as well

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Doesn’t seem to be any? We are a newly established factory; we are currently in the process of writing it!

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