Self-control design and installation drawings
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I’d like to ask if anyone in their factories actually follows the HGT 21581-2012 guidelines for automatic control installation. The design institutes always rely on these guidelines, and materials are selected based on them as well; when working at such institutes, it’s necessary to follow these guidelines or else the designs won’t pass the review. I’ve hardly ever seen plug-welded connections used in practice. For pressure take-offs using threads, a needle valve was used as the root valve, and that seemed fine to me (as I’ve worked in the fine chemical industry before). For flange-based pressure take-offs, ball valves are mostly used. The guidelines are only used as a reference. Additionally, I’d like to know how everyone handles the insulation of measurement pipelines – I hope you can give some advice. In the south, insulation for measurement pipelines carrying steam and water was never considered at all, and it seems that the methods suggested in the guidelines might not be appropriate either
In actual practice, many design institutes and enterprises indeed directly apply the atlases when implementing the standard HGT 21581-2012 “Atlases for Automation Installation”. This approach is mainly because using standardized atlases can reduce design errors, speed up the design process, and ensure the consistency and reliability of equipment installation. However, this approach does have some issues that make it unsuitable for specific scenarios. Regarding socket welding and pressure tapping, in practical operations, many on-site decisions are adjusted based on the availability of materials, costs, and process requirements. For example, the use of needle valves and ball valves, as you mentioned, often depends on specific process requirements and operational convenience. As for the issue of trace heating for pipelines, in the southern regions, due to the relatively warm climate, this issue may indeed not receive much attention. However, in the north, to prevent freezing in winter, it is usually necessary to heat-trace the measurement pipelines. There are various methods of heat tracing, such as electric heat tracing and steam heat tracing. When choosing a method, one must consider energy efficiency, cost, and ease of maintenance. Electric trace heating is relatively simple and offers flexible control, but its operating costs are relatively high ； The cost of steam tracing is relatively low, but a stable steam supply is required. It is recommended to adjust the design and material selection based on the actual working environment and specific requirements. Additionally, communicate with the drawing review department to ensure that the design complies with standards while also meeting practical application needs. .
If you are a designer, please draw according to the actual situation. The atlas serves as a reference; it can be modified—it’s not meant to be copied verbatim.
There’s nothing I can do; the senior generation rejected the drawings during the review, so they weren’t issued. I also transferred here from the field
I’m mainly concerned about how to control the temperature using steam tracing, in order to prevent the temperature at the measurement interface of the pressure transmitter from becoming too high and causing the silicone oil inside the diaphragm to boil. Ordinary silicone oil starts to boil at around 140°. Alternatively, could low-pressure steam tracing be used? Or, for measurement pipelines that are relatively short, isn’t it sufficient to insulate them just like the pipes themselves? It seems that using steam tracing is a waste of materials
It’s not easy! Look for old atlases; I hope you’ll create new atlases suitable for practical use on your own in the future. Previously, many pressure transmitters were designed according to Yokogawa’s specifications; now there are those with direct connections, and the old catalogues for vertical flanges are no longer applicable.