Instrument-related issues in the feasibility study report
Thread Content
Question 1: When an instrument requires a blowing system, how should the fault alarm or interlock for the blowing source be considered as appropriate? What does this mean? Question 2: How are the errors of thermocouples and thermal resistors calculated? Baidu is so chaotic; I still have to write the feasibility report
1. If your instrument selection includes blow-type instruments, a fault alarm should be installed for the air supply, or a valve interlock should be set up to prevent the material from coming into contact with the instrument in case of a fault. II. When selecting instruments, there is a precision grade for them; generally, we choose thermometers with a 0.5 grade, and that should be sufficient.
What bothers me the most are these purely theoretical word games. Chinese culture is profound and extensive; even a single character can have numerous interpretations, which is far less concrete than the pictorial representations used by ancient ancestors to record events. I understand that when using instrument air in detection instruments, it is necessary to consider the impact on production in the event of an instrument air failure. In the event of a problem with the instrument air, the monitoring instruments will fail to function. To ensure production safety, it is necessary to incorporate alarm indicators or interlock systems for such instrument air failures into the control system configuration. Essentially, this is redundant; whether it is a back-pressure system or a blowing system, the monitoring instruments used are still the same. When there is a fault with the instrument air (such as the instrument air becoming dirty and blocked, containing water that causes freezing, having low pressure leading to reverse flow, or the orifices in the throttle plates being blocked, etc.), the instruments will inevitably stop functioning (at their maximum or minimum levels). In control systems, important monitoring instrument points are designed to have upper and lower limit alarm functions. If such a monitoring point is critical, two-out-of-three or three-zone interlock functions are also implemented. Therefore, there is no need to set up any additional alarm interlocks in case of instrument air faults. The errors of thermocouples and thermal resistors require professional testing equipment, namely calibration instruments; thermocouples need a heating furnace, while thermal resistors require an ice-water mixture and a constant-temperature heating tank. Finding the error is essentially a form of calibration.
If it’s considered on a case-by-case basis, then it’s not necessary. There are many types of errors in thermocouples and thermal resistors; once the type is chosen, then the accuracy requirement can be determined.
If it’s considered on a case-by-case basis, then it’s not necessary. There are many types of errors in thermocouples and thermal resistors; once the type is chosen, then the accuracy requirement can be determined.