HG/T 20570.23-1995 Blind Plate Installation HG/T20570.23-1995 Standard Download Decompression Password: www.bzxz.net

Setting of blind plates
HG/T20570.23-95
Compiled by: Second Design Institute of the Ministry of Chemical Industrybzxz.net
Approved by: Ministry of Chemical Industry
Implementation date: September 1, 1996 Compiled by:
Li Xiao, Second Design Institute of the Ministry of Chemical Industry
Reviewed by:
Jiang Dongkui, Second Design Institute of the Ministry of Chemical Industry
Feng Shuyuan and Gong Renwei, Process System Design Technology Center of the Ministry of Chemical Industry
1 Classification and selection of blind plates
1.0.1 Blind plates are mainly used to completely separate the production medium to prevent the production from being affected or even causing accidents due to the loose closure of the cut-off valve. From the appearance, they are generally divided into 8-shaped blind plates, plug plates, and gaskets (plug plates and gaskets are blindly connected to each other).
1.0.2 Blind plates should be set at the locations where separation (cut-off) is required, such as the equipment connection port, before and after the cut-off valve, or between two flanges. It is usually recommended to use 8-shaped blind plates. For one-time use parts such as pressure and purging, plug plates (round blind plates) can also be used.
2.0.1 Locations where blind plates need to be installed
2 Blind plate installation
2.0.1.1 During the initial start-up preparation stage, when conducting strength tests or tightness tests on pipelines, blind plates need to be installed at the connection between equipment and pipelines if the tests cannot be carried out simultaneously with the connected equipment (such as turbines, compressors, gasifiers, reactors, etc.).
2.0.1.2 For various process material pipelines connected to the boundary area outside the boundary area, when the pipeline is still in operation when the device is stopped, blind plates are installed at the cut-off valves. 2.0.1.3 When the device is multi-series, the main pipeline from the outside of the boundary area is divided into several branch pipelines to enter each series, and blind plates are installed at the cut-off valves of each branch pipeline. 2.0.1.4 When the device needs to be regularly maintained, inspected or switched to each other, and the equipment involved needs to be completely isolated, blind plates are installed at the cut-off valves.
2.0.1.5 When the process pipelines of the pressurized pipeline, the replacement gas pipeline (such as the nitrogen pipeline, the compressed air pipeline) are connected to the equipment cabinet, a blind plate shall be installed at the cut-off valve.
2.0.1.6 The low points of the equipment and pipelines shall be drained cleanly. If the process medium needs to be concentrated in a unified collection system, a blind plate shall be installed after the cut-off valve.
2.0.1.7 Blind plates or thread plugs shall be installed after the valves of the exhaust pipes, drain pipes and sampling pipes of the equipment and pipelines. Non-toxic, non-hazardous to health and non-explosive materials are excluded. 2.0.1.8 When the device is constructed in phases, blind plates shall be installed at the cut-off valves for interconnected pipelines to facilitate subsequent engineering construction.
2.0.1.9 When the device is in normal production, some auxiliary pipelines that need to be completely cut off shall generally be equipped with blind plates. 2.0.1.10 Other occasions where the process requires the installation of breeding plates. 2.0.2 Examples of blind plate settings
2.0.2.1 The graphics of blind plates on PI diagrams shall comply with the industry standard "Graphic Symbols for Pipeline Instrumentation Flowcharts, Pipelines and Pipe Fittings" (HG20559.3-93). The 8-shaped blind plate graphics used in this regulation are shown in Figure 2.0.2-1. 570
(Normal Close)
(Normal Open)
Figure 2.0.2-18-shaped blind plate graphics
When the device is multi-series production, the blind plate settings are shown in Figure 2.0.2-2
Outside the boundary
Inside the boundary
Figure 2.0.2-2 The device is multi-series
The blind plate settings of the pressurized pipeline and the replacement pipeline are shown in Figure 2.0.2-3. Process pipeline
Charging or replacement pipeline
Figure 2.0.23
Equipment drainage
The blind plate setting of the equipment pipeline low point drainage is shown in Figure 2.0.2-4. Pipeline drainage
Guide, drainage collection main pipe
Figure 2.0.2-4 Equipment pipeline low point drainage
When the device is built in stages, the blind plate setting is shown in Figure 2.0.2-5. Phase I project
Phase I project
Figure 2.0.2-5
Phase construction of the device
Process pipeline
3 Precautions for blind plate setting
3.0.1 Under the premise of meeting the process requirements, as few blind plates as possible should be set. 3.0.2 The blind plates set must indicate whether they are normally open or normally closed. 3.0.3 Whether the blind plate is located upstream or downstream of the cut-off valve should be determined based on the cut-off effect, safety and process requirements.
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