I’ll come up with a discussion question too~

As a instrumentation technician, I would do the following: 1. Go to the control room and check the historical trends with the process engineers to determine whether the pressure readings are abnormal. 2. Prepare maintenance work orders and interlock operation orders. Note: The interlock operation ticket must be signed by a technician or deputy supervisor from the process workshop before the operation can proceed (a signature by the shift supervisor is invalid). The signature of the shift leader on the maintenance work order is valid. 3. The interlock must be disabled and a bypass circuit must be established before inspection can proceed. 4. Go to the cabinet room, disconnect the pressure signal from the safety switch, and check whether the 4–20mA signal coming from the primary gauge is normal. If the signal is abnormal, the problem lies either at the field equipment or in the cable running from the field to the control room. If the signal coming from the field is normal, then the problem lies on the control room side (check the connectors, terminal blocks, DCS settings, etc.). 5. Assuming the problem is in the field, once the instrument technician arrives there, he should first examine the appearance of the primary instruments (for example, check whether there are any leaks in the connections of pressure transmitters, the pressure leads, or the vent valves); if any problems are found, they should be addressed. If normal, proceed to the next step. 6. Open the instrument terminal blocks and check whether the connections are secure and whether the grounding is reliable. If a problem is found, address it. If normal, proceed to the next step. 7. Close the pressure tap valve, then slowly open the vent valve to see if the instrument reading returns to zero. If it returns to zero and stays stable. Then the problem may lie with the instrument itself, or it could be that the pressure tapping points and pressure lines are not properly unobstructed, or the process operations themselves are unstable. 8. If the gauge does not return to zero, it is necessary to remove the gauge and check whether there is any dirt attached to its diaphragm; if any issues are found, they should be addressed. If it were possible to see deformation in the membrane itself. Then, through verification, it is determined whether this instrument can continue to be used. (Determined by linearity, zero point, range, maximum allowable error, stability, etc.) If no film-bonding deformation can be detected visually, then it’s time to move on to the next step. 9. Verify the on-site instrument; by conducting this verification, it is possible to determine whether there is a problem with the instrument. (Determined by linearity, zero point, range, maximum allowable error, stability, etc.) If the instrument truly has a problem and can no longer be used, then replace it. Then analyze the reasons for the instrument damage; address those that can be fixed, and report those that cannot to higher authorities for handling during maintenance. 10. If the verification is passed, everything is normal. This means analyzing the reasons for the process together with the process engineers. 11. I believe that by doing this, the problem can be solved. 12. Personal summary; please feel free to point out any mistakes. If you think it’s right, give it more points! Hehe~~

This is a theoretical checking method, not very practical.

First, quickly determine whether the gauge signal represents the actual wind pressure or a false signal. If it is a false signal, disconnect the chain. (Is **proof** necessary here?) No time? ) Switch the relevant control to manual mode, and then conduct further analysis ； If it reflects the actual situation, inform the on-site operator; if necessary, seek approval from management so that they can take action. (If this is the truth, in case it triggers a chain reaction and an accident occurs, am I responsible?) ) In actual work, first tighten the signal wires of the instruments on site~ The blower has significant vibration.

Here, as long as it involves an interlocking point and there is no interlocking work order or the signatures on the interlocking work order are not in order, no one will carry out the work under any circumstances. Even if it means shutting down operations, if the necessary procedures aren’t in place, then just shut down and start again later. There’s nothing to do about it – the regulations regarding interlocking are extremely strict, with no room for ambiguity.

This is the final inspection process; many issues may have already been identified during the earlier stages, allowing for early resolution. But when analyzing a problem, can you not analyze it in this way? Just tell everyone that the pressure lead is blocked and that it needs to be fixed – you’re like a genius!

I think what the moderator said is feasible: first, go to the control room and ask the operators about the process situation to preliminarily determine whether it’s a problem with the instruments or with the process itself. If it’s determined that it’s an instrument issue, then disable the interlocks and go to the site to handle it. Generally, EJA transmitters rarely have problems, especially regarding air flow; first, check whether the fluctuations in the transmitters at the site are consistent with those in the control room. If the instrument still fluctuates, check whether the connections are loose, perform cleaning to remove contaminants, and if the problem persists, consult an instrument technician.

First, process-related factors must be ruled out. If it’s a problem with the instrument, the interlock must be disabled first. Problems should be handled from simple to complex

This post was last edited by broken01 on 2009-11-30 at 22:38. This is a representative issue; I asked our team leader for his opinion, and below are his answers for everyone to take a look at~ 1. Go to the site and ask the operators when the fluctuations started, check the relevant historical data, to see if there are any abnormalities in the process (such as air buildup or issues with the anti-surge valve), and if process-related causes can be ruled out, then check the instruments. 2. After obtaining the consent of the on-site operators and supervisors (it seems our factory doesn’t require any paperwork for this – addition), disconnect the interlock and proceed to the next step. 3. On-site, check whether there are any issues with looseness or leakage in the pressure guiding pipelines, and whether there are any abnormalities with the balance valves. If such issues exist, tighten them promptly (be careful not to cause large fluctuations in pressure during the process). If everything is normal, proceed to the next step. 4. Check whether the wiring terminals of the instruments on site are secure, as well as whether the corresponding terminals in the control cabinet are tight; use a screwdriver to tighten them carefully. If it is normal, proceed to the next step. 5. Check whether the power supply to the instruments is normal or not, and determine whether the issue lies with the distributor or with the PLC’s power supply system. To proceed with further troubleshooting (such as disconnecting the signal lines), it is necessary to obtain permission from the on-site operators and the management of the production unit (usually, this can only be done after the blast furnace has stopped producing molten iron). If the problem is with the distributor, replace it; if it is a problem with the PLC module, inform the specialized technicians at the production unit to handle it. If there are no problems, proceed to the next step: 6. Use the BRAIN manual controller to connect it to the instrument and check whether communication is possible. If communication is established, try sending signal values similar to those of the actual production pressure to see if the computer responds accordingly (this operation requires caution, and the operator should be informed to be careful). If the values do change, it proves that the signal lines are functioning properly. 7. Check whether there are any blockages in the pipelines. To address this, connect the instrument using the BRAIN manual controller; if communication is normal, supply a pressure value similar to the production pressure to the PLC. Then open the positive and negative pressure drain valves as well as the drain screws on the positive and negative pressure chambers of the instrument to carry out drainage and inspection (this process should not take too long, usually around 2 minutes). If it is normal, proceed to the next step. 8. Prepare a calibrated, normal instrument of the same type, set its parameters in advance, and replace the transmitter during the downtime when the blast furnace is not pouring iron. This operation must also be carried out with the consent of the on-site operators and supervisors.

What the colleagues above have said is all very good and comprehensive. I would just like to add that those working with instruments need to understand the production process, as it is of great help in identifying problems.

This post was last edited by zxd660913 on 2009-12-1 08:54. 1. The air supply pressure from the blast furnace blower has no interlocks; it is used solely to display the pressure in the pipeline network. 2. If the question setter made a mistake, I guess this pressure refers to the pressure at the fan outlet. The pressure at the fan outlet is an important parameter in the anti-surge system, as it is used to control the anti-surge valve. Apart from any operational or procedural issues, any fluctuation (instability) in this pressure would be a disaster (a purely instrumental issue), and it would be necessary to request that the machine be shut down. 3. A blast furnace blower with low air supply pressure cannot be part of the shutdown interlock; even the outlet pressure does not trigger such an interlock. 4. This question is purely a textbook exercise!