If there is a current deviation, what usually happens on the indoor DCS? How to tell?

Those with a flow indicator make it clear; for those without one, analysis and judgment are based on reference temperatures, etc. If necessary, an on-site inspection should be carried out for a comprehensive assessment.

Bias current can cause temperature differences, and it’s straightforward to make judgments based on temperature!

With flow deviation, the flow readings for each branch in the DCS show significant errors; the temperature of each branch is also affected, though there is a considerable delay. Generally, it’s sufficient to rely on the readings from the flow meters – these are all part of the basic parameter display functions of the DCS. As for things like pressure and sound at the site, it takes some time to get a sense of them. . .

DCS remote control generally has a certain degree of latency, so it is necessary to pay close attention to temperature changes in a timely manner

Normally, a flow rate measurement is not really necessary; temperature is usually the relevant parameter. Thermocouples are inexpensive, while investing in flow rate measurement systems incurs high costs in terms of maintenance over time. The temperature is most evident as seen on the DCS, but it is necessary to have measurement points at each branch. Temperature measurement points should be established on-site (infrared sensors are sensitive to silver powder; light is scattered in such cases, making accurate measurements difficult). To address this issue, identify the appropriate measurement points along the pipelines, remove a portion of the insulation from those areas, and paint them black using a black dye to serve as measurement points. A schedule for regular measurements should be established, requiring the crew to carry out these measurements on a regular basis. In fact, the temperature changes in the branch pipes are already quite delayed. These temperature changes indicate that some of the air-cooling tubes in those branch pipes have stopped functioning. It is necessary to conduct systematic measurements on these air-cooling tubes, identifying the points where deviations are likely to occur or those that require close monitoring (such as the areas near the air inlets on the air-cooling tube plates), in order to ensure proper temperature monitoring. The key is on-site handling and monitoring; things are still quite delayed indoors.

The deflection flow depends mainly on temperature; the flow hole valve is prone to failure, while the temperature remains relatively stable. Additionally, the pressure gauges on site will show reactions; for example, if there is a deviation in the flow of gas from the furnace, some of the gas will vaporize, and the pipelines will vibrate.

It is unreliable to determine whether there is a flow deviation by checking the flow rates in each channel, as the errors of flow meters are relatively large; checking the temperature is a more reliable method.

Bias flow: Check flow rate, temperature, and on-site pressure