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Generally, the installation location of on-site instruments should meet the following requirements: 2. Avoid areas with high temperatures and severe vibrations. 4. It has protective measures to adapt to the on-site environment. 6. When non-explosion-proof instruments are used in explosive hazardous areas, they should be installed in positively pressurized instrument cabinets or other explosion-proof measures should be taken, in compliance with relevant explosion-proof standards. 2 The connection between instruments and the process flow must meet the following requirements: 2. Unless otherwise specified in the design, the minimum nominal pressure of the connection flanges for the pressure transfer pipes used for instrument measurements shall comply with the following provisions: b) The nominal pressure of flanges for Class B and C pipes should not be lower than 2.0 MPa ； 4. Unless otherwise specified in the design, the gaskets used for flange sealing shall meet the following requirements: b) For pipelines containing highly toxic or flammable media, or those operating at high temperatures, with large temperature differences, and subject to mechanical vibration or pressure fluctuations, wound gaskets are recommended, and they must meet the usage conditions specified in Table 1: http://mmbiz.qpic.cn/mmbiz_jpg/h7BDOibZSgSM8EaXuNAz9G17LBes6yzjzKgF6IXkhIwdfo2WfnAmdlOiaMTOIkbZRkF8rbXgFGREQ99ZspAQXn6Q/0?wx_fmt=jpeg 5. The material used for flange fasteners shall comply with the requirements specified in Table 2. http://mmbiz.qpic.cn/mmbiz_jpg/h7BDOibZSgSM8EaXuNAz9G17LBes6yzjz5lvxQQUEkrdJTBJnXSXScibiaLicyibb4jkcSvC9LJjUqCH7uWIicuYKfdw/0?wx_fmt=jpeg ② Soft gaskets refer to those with a tightening specific pressure of y≤31MPa and a gasket coefficient of M≤2. Gaskets with higher Y and M values are all non-soft gaskets. 7. The location of the instrument connections (nozzles) should facilitate the installation and maintenance of shut-off valves or measuring elements; where necessary, a dedicated operating platform or ladder should be provided. 3 The pressure guiding pipes for static pressure measuring instruments shall meet the following requirements: 1. The pressure guiding pipes should preferably be made of stainless steel or carbon steel pipes with dimensions of Ф14x2 or Ф18x3; other types of pipes can also be used. 3. The source valve at the root should preferably be a gate valve, globe valve, or ball valve; other types of valves can also be used. a) The instrument is equipped with vent and drain ports; c) Highly corrosive media. 6. Isolation tanks (condensation tanks) should be installed for media that are prone to clogging, corrosion, viscosity, as well as steam. 8. When measuring cryogenic liquid media at temperatures below -29°C, the pressure transfer pipes must meet the following requirements: b) There should be a sufficient length of vaporization section between the point where the medium leaves the equipment or pipes and the valve before the instrument, so that the temperature inside the pressure transfer pipe is close to the ambient temperature; the pipes should also be installed at an upward slope. It is also possible to use a low-temperature resistant isolation fluid for pressure transfer after the source valve at the beginning of the pipeline; d) The material used for the pressure transfer pipes in the cryogenic section must be stainless steel, and welding should be used for their construction. a) When measuring gaseous media, use a cold medium gas or another cold gas that has no impact on the process to blow back and take the pressure reading; c) Starting from the instrument connection fitting (nozzle), use a stainless steel pressure guide tube, followed by a sufficient length of heat dissipation section, before connecting to the source valve. 11. The pressure guide tube should be fixed to a steel structure or platform; when this is not possible, it can also be fixed to uninsulated equipment and pipelines. Temperature measuring instruments: http://mmbiz.qpic.cn/mmbiz_jpg/h7BDOibZSgSM8EaXuNAz9G17LBes6yzjzZ4YD7bf5u1kagMbyTqtZCqJ2jtyHMxG3daxloX67YzCib24JB6AGmdA/0?wx_fmt=jpeg1. Flange connection is required; for the installation of thermometers, flange connections or threaded connections are generally used. Flange connections should be used in the following cases: 2. When the operating temperature of the medium in the pipes and equipment is greater than 370℃ ； 4. Pipes and equipment made of alloys or linings ； 6. Measuring toxic media ； 7. Heating furnace. 2 The installation of temperature measurement elements shall comply with the following requirements: 2. When installed in a straight pipe section, it can be placed vertically or at an angle of 5° inserted into the pipe; when installed at bends or similar locations, it should be oriented in the opposite direction to the flow of the medium. The insertion depth of the thermometer ((L)) is calculated using the following formula: where L1 is the length of the instrument connector in mm, and U is the immersion length in mm. When measuring gas: UG = LS + 25 mm. UG – the immersion length of the gas (mm) ； Note: The sensitive section length of thermocouples is approximately 22 mm, while that of thermal resistors and bimetallic thermometers is about 40 mm. For pressure-type thermometers, the sensitive section length is equal to 1.5 times the length of the temperature sensing element. The length of the end portion of the protective tube surrounding the thermocouple used for measuring furnace temperature should be 50–100 mm longer than the length of the furnace tube ； The cantilever length of horizontally installed thermocouples inserted into the furnace should not exceed 600 mm ； The wiring box of the thermocouple installed in the elbow box should be located outside the insulation layer of the elbow box. a) A flange or threaded connection should be used between the thermocouple and the furnace chamber; c) The blade-like end of the thermocouple must be firmly welded to the furnace tube, with the length of this blade being at least 50 mm. An appropriate metal clip should be used near the blade to secure the thermocouple to the furnace tube. a) Thermocouples or thermistors at different elevations should be installed in the same orientation; c) The length of the thermocouple or thermistor inserted into the equipment must be no less than 150 mm; 8. The length of the end of the wear-resistant thermocouple protection tube that protrudes from the outer sleeve of the equipment should be between 100 and 150 mm. 9. The insertion depth of the thermometer on the storage tank should not be less than 500 mm, and its installation position should be 600 mm above the heating coil inside the tank. The thermometer installed on the floating roof tank should not prevent the movement of the floating roof. 3 When temperature measuring elements are installed in the following situations, a thermometer sleeve should be used: 2. Non-flammable fluids at high pressure; 4. Non-flammable fluids flowing at high speeds; 5. Large-diameter pipes. 4. The use of thermometer sleeves shall comply with the following regulations: 1. The operating pressure of the sleeve shall not exceed the maximum allowable operating pressure of the sleeve at the corresponding operating temperature. 2. The operating flow rate of the sleeve should not exceed the maximum flow rate that the sleeve can withstand at the corresponding operating temperature.