Commonly used installation materials for meters

There are many instrument pipelines (also called pipelines and pipelines, which can be divided into four categories, namely pressure guiding pipes, pneumatic pipes, electrical protection pipes and heat tracing pipes. 1. Pressure guiding pipes Pressure guiding pipes, also known as pulse tubes, are directly related to the process medium. The first pipe at the junction angle is the most used, most demanding, and most complicated type of pipe for instrument installation. Since the pressure guiding pipe directly contacts the process medium, the choice of the pipe and the pipe to be instrumented (also called pipelines and pipelines are many, It can be divided into four categories, namely pressure guiding tube, pneumatic tube, electrical protection tube and heat tracing tube. 1. Pressure guiding tube Pressure guiding tube, also known as pulse tube, is a pipe that directly connects with the process medium and is used for instrument installation. The most used, most demanding, and most complicated type of pipeline. Since the pressure guiding tube directly contacts the process medium, the selection of the pipe is related to the physical properties, chemical properties and operating conditions of the measured medium. The general requirement is that the pressure guiding tube works in Under pressure or normal pressure conditions, it must have certain strength and tightness. Therefore, seamless steel pipes should be used for this type of pipeline. In the medium and low pressure medium, the commonly used pressure guiding pipe is ф14×2 seamless steel pipe, which is the most used A kind of pipe. Sometimes ф18×3 or ф18×2 is also used. The sampling pipeline for analysis is usually also ф14×2 seamless steel pipe, sometimes ф10×1.5, ф10×1 or ф12×1 seamless steel pipe. In Under high pressure operation conditions exceeding 10Mpa, ф14×4 or ф15×4 seamless alloy steel pipes are mostly used. The selection of pressure guiding pipe must meet the process requirements and design requirements, and the design approval must be obtained for substitution. 2. Pneumatic pipelines and pneumatic pipelines It is called the air source pipe or pneumatic signal pipe. Its usual medium is compressed air. The compressed air is treated to be dry, oil-free, and clean compressed air without mechanical debris (sometimes nitrogen is also used). Its working pressure is 0.7~0.8Mpa. The gas source main pipe is usually used as a kind of outer pipe by the process piping specialty. It is installed at the entrance of each device and the instrumentation specialty is responsible for the inlet. Usually the gas source pipe of the process outer pipe is mostly DN100, which is 4, , Pipes, in individual cases, DN50, that is 2, pipes. Generally seamless steel pipes. The pneumatic pipes that are professionally laid by the instrumentation of the equipment are DN25, that is, the galvanized welded steel pipes below (formerly known as galvanized steel pipes). Water gas pipe). General main pipe is DN25, namely 1,,, branch pipe is DN20, namely 3/4, and DN15, namely 1/2,, galvanized welded steel pipe. Connected to the first pneumatic instrument and pneumatic control valve. The other are red copper pipes and coated uranium pipes (the purple steel pipe has a plastic protective layer outside), mostly ф6×1, and in some cases, there are also ф7×1 or ф8×1 purple steel pipes and nylon 1010 ф6×1 pipes. Tubes and cables are used in the occasions where a large number of pneumatic instruments are used, most of which are ф6×1 covered tubes and nylon tubes. 3. Electrical protection tube Electrical protection tube is also a word that is frequently used in instrument installation. It is used for protection Cables, wires and compensation wires. For aesthetics, galvanized seam pipes are often used, that is, electrical pipes, and sometimes galvanized welded steel pipes are also used. Special electrical pipes have thinner walls, and their specifications are shown in Table 5-2-1 The specifications of galvanized welded steel pipe are shown in Table 5-2-2. Table 5-2-1 Specifications of electric pipes Nominal diameter DN, in1/25/83/4111/411/22 Nominal diameter DN, mm15182025324050 outer diameter, mm12.715.8719.0525.431.7538.150.8 wall thickness, mm1.61.61.81.81 .81.82.0 inner diameter, mm 9.512.6715.4521.628.1534.546.8 Weight Kg/mm 0.4510.5620.7651.0350.3351.6112.40