Regarding the commissioning of instruments for the new installation
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During the construction of new installations, the installation of instruments is generally carried out at a later stage. What is the sequence regarding process work and equipment installation? 1: Is it necessary to wait until the process pipelines have been installed and the slag has been removed before installing instrument orifice plates, valves, etc.? 2. Process pipelines need to undergo purging, pickling, etc. What should the instrumentation team pay attention to? 3. When can the instruments generally start to be put into use, that is, when is the first valve of the instrument’s pressure lead pipe opened to connect it with the process pipeline?
Temperature: If there is a sleeve, it can be installed first, so that the thermometer does not come into direct contact with the medium. Holes without sleeves can also be drilled first; they can be blocked off during purging. Pressure: 1. The primary valve and pressure lead pipes can also be installed first, with purging carried out later. 2. The flanges for connecting the diaphragm gauge can also be welded in advance, and blind flanges can be used to block them during purging. Valve: Weld a short section directly, and install it after the pipeline has been purged. That’s all I can think of. Anyway, the instrument panel is the final stage of production; as long as it doesn’t affect or damage the instrument panel, it can be installed
During the construction of the new facility, 80% of the work related to equipment and pipeline installation can be carried out, as well as the installation of on-site instruments; previously, only the installation of control system cabinets and channel testing could be done. 1. Once the process pipelines are installed, it is then possible to install instrument orifice plates, valves, and similar components. 2. Process pipelines must undergo purging, pickling, etc. The instrumentation team should note that online pipeline instruments (vortex flow meters, mass flow meters, electromagnetic flow meters, rotameters, valves, orifice plates) must be removed and replaced with bypass devices; pressure tapping pipes should be disconnected behind the root valve whenever possible. During the purging of cage valves, weld slag and foreign objects can block the valves and damage their internal components, rendering the cage valves unusable – and the cost of replacing these internal components is very high. 3. The instrument can be put into use when the process water is activated, that is, when the primary valve of the instrument’s pressure lead pipe is opened. The start of trial operation of the process is exactly when the instruments are busiest; there are problems either with the installation or with the clamps not being tightened properly, or leaks at the flanges. There’s nothing that can’t happen – nothing that goes unnoticed. One must be prepared for the worst. After experiencing driving in such harsh conditions once, you won’t want to do it again – it involves working overtime for either all night or several consecutive days.
Pay special attention to the orifice plate; install it after purging but before transporting with water
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After the piping and equipment have been installed, holes are made at the locations where instruments need to be installed. To measure pressure and differential pressure, the primary valve must be installed first; be sure to close it after installation. Resistance thermocouples with protective sleeves can be installed directly, while those without such sleeves need to be temporarily sealed in some other way. Throttling elements cannot be installed yet – the construction team will find a way to create a short circuit to connect the pipes together. It is also advisable not to install other types of flow meters for now. Make the openings and ensure they are properly sealed before purging the pipes; after successful purging, install the instrumentation.