Is it necessary to install a blind flange on the drain valve located below the magnetic flap level gauge?
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Some safety experts have suggested that a blind flange should be installed on the drain valve located below the side-mounted magnetic level gauge, in order to prevent leaks. Is there such a requirement in the field of instrumentation?
It mainly depends on the medium: is it toxic and flammable? It is also necessary to prevent leaks
This post was last edited by lijie2007521 on 2022-6-8 10:27; the valve outlet was sealed with a plug. Since there is a certain pressure present in the area between the blind flanges in case of leakage, it is recommended to install a valve to allow for slow pressure release.
The expert inspection suggested that the equipment has pipe valves facing the air, and blind plates need to be installed. Some drain ports of storage tanks, feeding ports of storage tanks, sampling ports on equipment pipelines, etc., all require such treatment. Although I found it extremely inconvenient for daily operations, since I wasn’t aware of the source of the standard, I had no choice but to agree to make the necessary adjustments first. Later, I found out that it was the standard \"HG T20570.23-95 – Installation of blind flanges\", which is merely a recommended standard. Inside, there is a 2.0.1.6 device for draining the low points of pipes; if the process medium needs to be collected in a unified system, a blind flange is installed after the shut-off valve. 2.0.1.7 Blind plates or plug valves should be installed behind the valves on the exhaust pipes, drain pipes, and sampling pipes of equipment and pipelines. Except for materials that are non-toxic, pose no health hazard, and are not explosive. Exemptions apply only to “harmless, non-explosive materials”. This standard is over 20 years old now; I’m not sure if there are any new guidelines available for reference
It is not recommended to use blind flanges; instead, connecting flanges can be considered, along with short pipes. Threads should be provided at the ends of these short pipes, and they can be sealed using pipe caps, which also facilitate cleaning. The pipe caps and short pipes can be connected together with chains, and then welded in place.
It can be installed or not. Assess the severity of the leak. In fact, for instruments equipped with side-mounted connection pipes, it is best not to install flanged valves below the connection pipes. The diagram below shows the waste discharge connection recommended in the installation manual.
Indeed, whenever an inspection is conducted, it is necessary to check on site whether the plug is missing; the plug must indeed be checked.
Put a plug in it? I need it. Even if it’s for testing water, I still need it; after all, a plug isn’t expensive