【Daily Question 20090324-25】Routine inspection of instruments
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Do you think instrumentation teams in manufacturing enterprises should conduct inspections? If there are certain locations that need to be inspected, do you have anyone around you who conducts inspections to identify potential problems with instruments? Participants are required to organize their own wording and avoid repeating posts; each participant earns 5 points, while those whose suggestions are adopted receive 10 points per suggestion! Summary: 1. Daily maintenance of instruments should involve inspections, with the frequency ranging from 2 to 4 times per day; additional inspections are required for key units and control systems. 2. Inspection contents: 1. Check whether the instrument readings and records are normal; verify that the readings of the field primary instruments (transmitters) are consistent with those of the instruments in the control room as well as the control instruments, and that the output readings of the regulators match the positions of the control valves (usually, two instrument technicians are required to conduct this inspection). If there are no significant changes in the manufacturing process, it is normal to observe a time delay between the production site and control systems ； 2. Check whether the power supply for the instruments (including UPS) and the air supply meet the specified requirements ； 3. Check the insulation and heat tracing conditions of the instruments ； 4. Check for damage and corrosion on the instrument body and connectors ； 5. Check for leaks at instruments and process interfaces ； 6. Check the condition of the instruments. The standards for integrity are based on the procedures for maintenance, repair, and calibration of measurement equipment. 7. Check whether the position of the control valve actuator is normal, whether the air supply as well as the electrical and pneumatic signals to the valve positioner are functioning properly, whether there are any leaks at the connections, and whether the valve stem is vibrating (i.e., whether there is excessive noise) ； 8. Check whether the key parameter values are operating normally, such as the liquid level of critical equipment, as well as key metrics like flow rate, pressure, and temperature ； 9. Are the indicator values of important rotating equipment within normal ranges? This includes parameters such as the anti-surge control of compressor units, shaft vibration, shaft displacement, bearing temperature, rotor and stator temperatures, as well as whether the primary components are functioning properly ； 10. Are there any leaks in the high-pressure pipelines and heat tracing pipelines? ； 11. For some equipment or instruments that require the removal of waste fluids or gases, such discharge must be carried out promptly; for example, the molecular sieve needs to have its deposits removed, and if the felt becomes damaged, it should be replaced immediately ； Venting and draining of the transmitter pressure guide tube, etc. This post was last edited by baodingzhai on 2009-3-26 15:49]
Daily maintenance of instruments should involve inspections, primarily to check the air supply pressure of pneumatic valves and the status of the UPS power supply.
I. The arrangement of inspection routes must adhere to the following principles: 1. Important monitoring and control points； 2. At the instrument equipment where problems occur frequently ； 3. Key maintenance points for critical equipment in large-scale units and installations ； 4. Some blind spots in the line of sight, areas that are difficult to inspect ； 5. Conduct inspections at fixed times, in fixed locations, and with a fixed number of personnel; it is advisable to keep the time interval between inspections at around 4 hours ； (Depends on the size of the production facility) ； 6. Strictly implement the inspection system and carry a tool kit with you at all times ； 7. Conduct inspections at the workshop level at least twice a week to use as a basis for evaluation ； 8. Random inspections at the plant level are conducted on a monthly basis to ensure the implementation of the inspection system. II. During inspections, there were quite a number of instances of leaks, spills, and other such problems; major equipment accidents were rarely detected during inspections ； During winter, inspections related to anti-freezing and insulation, as well as heating systems, are key aspects of routine maintenance. Problems such as frozen surfaces and frozen pressure lines are often encountered; addressing them promptly prevents significant losses. III. Inspections of areas that are not visible under normal circumstances can be carried out promptly, especially at the heights of towers and containers; the proper operation of both instruments and process equipment is a necessary condition for ensuring smooth production. Just a humble opinion; thanks for paying attention.
Daily inspections mainly consist of the following: Based on the distribution of instruments in the area under supervision, the optimal inspection route is determined, with inspections being carried out at least twice a day. During routine inspections, instrument technicians should be familiar with the operation of the instruments, just as the process operators are. 1. Check whether the instrument readings and records are normal; verify that the readings from the field primary instruments (transmitters) are consistent with those on the displays in the control room, as well as with those of the control instruments. Also ensure that the output readings of the regulators match the position of the control valves (usually, two instrument technicians are required to conduct this check). If there are no significant changes in the manufacturing process, it is normal to observe a time delay between the production site and control systems ； 2. Check whether the power supply for the instruments (including UPS) and the air supply meet the specified requirements ； 3. Check the insulation and heat tracing conditions of the instruments ； 4. Check for damage and corrosion on the instrument body and connectors ； 5. Check for leaks at instruments and process interfaces ； 6. Check the condition of the instruments. The standards for integrity are based on the procedures for maintenance, repair, and calibration of measurement equipment.
The instrumentation department in manufacturing enterprises must carry out inspection tasks. Contents of the routine inspection: Whether the air source pressure is normal, and drainage from the air storage tank ； Temperature indication, recording curve, recording ink ； Check whether there are any jumps in the flow rate indication and the readings of the automatic analyzer ； Is the power supply voltage of the instrument normal? ； Are the automatic control curves for liquid level, flow rate, concentration, pressure, etc. smooth without any jumps, and so on?
Our company’s “Routine Inspection System” was established to gain a comprehensive understanding of the operating conditions of automatic control and instrumentation equipment, to identify problems in advance, address them promptly, and ensure the safe and normal operation of production processes. 1. Assign 1–4 electrical and instrumentation personnel for the shift to conduct inspections of the automatic control equipment within each group’s responsibility area. 2. Conduct a routine inspection once a day, carefully assess the operation of the automatic control equipment, and record the findings promptly. 3. During inspections, one must follow the steps of “look, listen, ask, and check”. “\"Take a look\" refers to checking the display readings on various instruments and equipment to see how they are operating ； “The second listening step involves listening to the problems reported by operators and workshop supervisors, as well as the requests they make ； “The “three questions” refer to asking in detail about the operating status of the instrumentation equipment and the symptoms of any faults ； “The “four inspections” refer to using tools to check for issues with instrumentation and equipment and addressing them promptly. 4. During inspections, essential common tools and maintenance supplies (nylon straps, wrapping tape, electrical tape, etc.) must be carried. For issues that cannot be resolved or require a long time to address, it is necessary to immediately inform the shift supervisor in charge of electrical and instrumentation and higher-ranking managers, requesting additional personnel to be sent. Inspection personnel must wait for additional staff to arrive and ensure the issues are properly handed over before continuing with the inspection. 5. Inspection records must be detailed and accurate, with clear handwriting. 6. The status of issues that have been resolved and the reasons for those that remain unresolved must be clear. 7. Signatures in the workshop must be genuine; proxy signing, retroactive signing, or omitted signing are strictly prohibited. 8. The daily inspection record book must be submitted to the shift supervisor for review and signature approval before being given to the relevant personnel in the white-shift team. 9. The shift supervisor must conduct thorough inspections and detailed inquiries to gain a comprehensive understanding of the operation status of the instruments and equipment on that day, and arrange tasks accordingly. For cases where instrument failures occur again after inspections, a dedicated person is assigned to investigate and address the issue; if this is due to the inspector’s lack of responsibility and the problem remains unresolved, the relevant provisions of the Assessment System shall be applied. This post was last edited by zlky2005 on 2009-3-24 08:20]
It is important to strengthen the regular inspections of instruments. During these inspections, special attention should be paid to the control instruments in critical areas, such as flow control valves, flow meters, and level gauges. The DCS system also requires frequent inspection; one instance of distorted readings from a level gauge almost led to a dry boiler condition, but this was avoided thanks to timely detection! !
I’ve been to large fertilizer plants where there are specialized instrument technicians who conduct regular inspections. But for small devices like ours, the inspection of instruments is incorporated into the routine checks of the processes and equipment. To be honest, many problems arise as a result of this. At present, the operators are not aware of this and cannot find it, but the duty personnel are required to conduct regular inspections of the instrument system, including UPS, DCS, transmitters, instrument air, and so on.
I think inspections should be carried out. Our company is a manufacturing enterprise, and our instrument technicians conduct inspections on a daily basis, focusing on key instrument points as well as the heating systems for those instruments. There are specific inspection routes provided, and these inspections can indeed help identify many potential problems.
I. The arrangement of inspection routes must adhere to the following principles: 1. Important monitoring and control points； 2. At the instrument equipment where problems occur frequently ； 3. Key maintenance points for critical equipment in large-scale units and installations ； 4. Some blind spots in the line of sight, areas that are difficult to inspect ； 5. Conduct inspections at fixed times, in fixed locations, and with a fixed number of personnel; it is advisable to keep the time interval between inspections at around 4 hours ； (Depends on the size of the production facility) ； 6. Strictly implement the inspection system and carry a tool kit with you at all times ； 7. Conduct inspections at the workshop level at least twice a week to use as a basis for evaluation ； 8. Random inspections at the plant level are conducted on a monthly basis to ensure the implementation of the inspection system. II. During inspections, there were quite a number of instances of leaks, spills, and other such problems; major equipment accidents were rarely detected during inspections ； During winter, inspections related to anti-freezing and insulation, as well as heating systems, are key aspects of routine maintenance. Problems such as frozen surfaces and frozen pressure lines are often encountered; addressing them promptly prevents significant losses. III. Inspections of areas that are not visible under normal circumstances can be carried out promptly, especially at the heights of towers and containers; the proper operation of both instruments and process equipment is a necessary condition for ensuring smooth production.
Our company assigns instrument technicians to carry out inspection tasks every two hours. Inspection items: Whether the pressure of the instrument air supply is normal, and whether the automatic valves are in the correct position ； Are the temperature and flow rate indications, as well as the readings from the automatic analyzer, normal? ； Is the power supply voltage of the instrument normal? ； Whether the automatic control curves for liquid level, flow rate, concentration, pressure, etc. are smooth without any jumps, and whether there are any instances of leakage or other such problems.
Inspections are carried out once per shift, mainly focusing on the instruments installed on site: draining water from pneumatic valves, checking the air supply, weight measurement modules, etc. It also includes checking level gauges, pressure gauges, temperature sensors, etc., to determine if there is any damage or leakage. When production is high, the second shift
I believe that routine maintenance of instruments should certainly include inspections, focusing mainly on primary instruments and secondary instruments, as well as the UPS power supply.
Inspections must be carried out. The items to be checked include the power supply for the instruments (including USB), the instrument air supply, the connection status between the instruments and pipelines, and the operation of the DCS. During these inspections, leaks at the interfaces as well as power supply failures for the instruments were detected
(1) Check whether the primary instruments, secondary instruments, control valves, control components, as well as the monitoring and control points within the DCS system in the jurisdiction are operating properly. (2) Check whether the markings and alignment of instruments in the area are in good condition, and whether the trend records of various monitoring and control points in the DCS system are normal. (3) Ensure that the power supply for instruments in the area is adequate, and carry out regular cleaning of the instrument air supply sources. (4) Verify that the process parameters being controlled by the various control circuits in the area are stable, and that the deviations at the instrument control points remain within acceptable limits. (5) Check whether there are any blockages or leaks in the instrument pipelines and control valves in the area, and ensure that appropriate anti-corrosion measures have been taken. (6) Inspect to ensure that the insulation, cooling, and anti-freezing measures for instruments, control valves, pressure guiding pipes, and other related equipment in the area are in place. (7) Check whether the areas behind instrument panels and inside instrument cabinets in the control room are tidy and meet the “5S” standards. (8) Verify that the instrument rest rooms, engineer stations, and control stations in the area are tidy and comply with the “5S” standards. (9) Identify any potential safety hazards associated with the instrument equipment and its operating environment. I’d like to add a few of my own thoughts. When I was working at that factory, I accompanied the inspectors on site, and I was surprised by their behavior – they simply flipped over the inspection tags without checking anything else. This posed a serious safety risk. I’m from the instrumentation field, and once I went to the site with an operator and found that there was a leak in one of the internal circulation pump pipelines; liquid was spraying out in large amounts. Yet the people in charge said it could wait until Monday to be repaired, and as a result, it took two days before anything was done. There was about 5% hydrochloric acid in that pipeline. Since then, I’ve realized that inspections aren’t just a superficial task; it’s a crucial responsibility. Everyone, whether they’re instrumentation technicians or process operators, must carry out their inspections diligently, being responsible for themselves and others, and truly achieving the principle of ‘no harm to self, no harm to others, no harm to the environment.’ Last edited by hallon520 on 2009-3-24 09:37
Instrument technicians generally have a designated area for inspecting the instruments under their responsibility; they determine the most efficient inspection route based on the location of those instruments, and conduct inspections at least twice a day. During routine inspections, the instrument technician should consult the operators regarding the operation of the instruments during that shift, and address any issues that arise in their operation promptly. The inspector’s checks focus on the following aspects: (1) Verifying whether the instrument readings and records are normal, whether the readings of the field primary instruments match those shown on the control room instruments and control devices, and whether the output readings of the regulators correspond to the positions of the control valves. (2). Check whether the power supply for the instruments (AC220V or DC24V) and the air supply are within the normal range. (3). Check the insulation and heat tracing condition of the instruments. (4). Check for damage and corrosion of the instrument body and connectors. (5). Check for leaks at the instruments and process interfaces. (6). Check the condition of the instruments. The condition of the instruments can be checked in accordance with the \"Equipment Maintenance and Repair Procedures\" issued by the Ministry of Chemical Industry.
Instrument technicians generally have a designated area for inspecting the instruments under their responsibility; they determine the most efficient inspection route based on the location of those instruments, and conduct inspections at least twice a day. During routine inspections, the instrument technician should inquire with the operators about the operation of the instruments during that shift, and address any issues that arise in their operation promptly. During their inspections, instrument technicians focus on the following aspects: 1. Checking whether the instrument readings and records are normal, whether the readings of the field primary instruments match those displayed in the control room, and whether the output readings of the controllers correspond to the positions of the control valves. 2. Check whether the power and gas supplies for the instruments are within the normal range. 3. Check the insulation and heat tracing condition of the instruments. 4. Check for damage and corrosion on the instrument body and its connectors. 5. Check for leaks at the instruments and process interfaces. 6. Check the condition of the instruments. 7. In case of any issues, promptly contact the process team for cooperation in resolving them
1. Inspections should be carried out. 2. The area we inspect includes all instruments throughout the entire plant, and specific inspection procedures and requirements for each type of instrument have been established, with corresponding records kept. In principle, our approach is to reduce the number of inspections while ensuring their quality. 3. Potential fault hazards identified: the working environment of the instruments, such as leaks, and abnormal insulation or heating of the instruments.
Inspections are necessary, focusing on key instrument points and instrument heating.
It is of course necessary for the instrumentation department in manufacturing enterprises to conduct inspections; this is a requirement. When I am on site performing maintenance on the instruments of the ammonia synthesis plant, I conduct inspections twice a day. That is, inspections begin upon arriving at work in the morning, followed by a team meeting; then there is a handover between the night shift and the day shift ； Conduct inspections after starting work at noon to identify and resolve issues promptly ； For those on the day shift, a final inspection is carried out before ending the shift, after which they hand over duties to those on the night shift. During inspections, the instrumentation staff first go to the control room to conduct a check, communicate with the operators to see if there are any issues with the control system, and then proceed to the site to specifically inspect important primary instruments such as the transmitter connections for any leaks ； Check whether the ammeter indicates normally and whether the heat preservation and heating systems are functioning properly ； Check whether the position of the control valve actuator is normal, whether the air supply as well as the electrical and pneumatic signals to the valve positioner are functioning properly, whether there are any leaks at the connections, and whether the valve stem is vibrating (i.e., whether there is excessive noise) ； Check whether the key parameter values are operating normally, such as the liquid level of critical equipment, as well as flow rates, pressures, temperatures, and other important indicators ； Whether the indicator values of important rotating equipment are within normal ranges, such as the anti-surge parameters of compressor units, shaft vibration, shaft displacement, bearing temperature, rotor and stator temperatures, etc., as well as whether the primary components are functioning properly ； Are there any leaks in the high-pressure pipelines and the heat tracing pipelines? ； Also, some equipment or instruments require the removal of waste fluids or gases, which must be discharged promptly; for example, the molecular sieve needs to have its deposits removed, and if the felt becomes damaged, it should be replaced immediately ； Venting and draining of the transmitter pressure guide tube, etc.
All instrument-related positions in manufacturing enterprises have an instrument inspection system. Inspection frequency: Instrument inspections are generally carried out during the day shift, once in the morning and once in the afternoon. Inspection route: The area under the responsibility of the instrument technician; the specific route ensures that every operating station can be inspected. Inspection contents: 1. Check the operating condition of the instruments on site, and inspect the instrument pipelines for any leaks. Clean and drain the on-site instruments, and check the status of the instrument air supply. 2. Check the display status of the secondary instruments in the control room, and inspect the operating status of control systems such as DCS and PLC ； Check the operating status of the UPS. 3. Ask the on-duty process personnel about the operating condition of the instruments. 4. Address and document the issues identified during inspections.