HG/T 20637.4-1998 Preparation of instrument construction and installation requirements
Some standard content:
Preparation of Requirements for Instrumentation Construction and ErectionHG/T20637.4-1998Preparation unit: China Tianchen Chemical Engineering CorporationApproval department: State Administration of Petroleum and Chemical IndustryImplementation date: January 1, 1999Preparer: Song XiaoxianReviewer: Gao XinSun GongzhanWang DazhengWang Ximing1General Principles1.0.1This regulation is prepared to obtain accurate control measurement, meet the requirements of convenient instrument maintenance and operation, and correctly and reasonably determine the installation location of the instrument. 1.0.2This regulation is used to guide automatic control design personnel to prepare instrumentation construction and installation requirements for engineering projects. Or guide designers to select and supplement the instrumentation construction and installation requirements (general) in Appendix A of this regulation to form the instrumentation construction and installation requirements for engineering projects.
1.0.3 When implementing this provision, the provisions of the relevant national standards in force shall also be met. 321
Contents of instrument construction and installation requirements
2.1 General provisions
2.1.1 The location of the process field instrument installation shall meet the requirements of accessibility, and corresponding measures shall be taken in case of special circumstances.
2.1.2 The installation accessories connected to the process shall meet the piping level 2.1.3 The specifications, materials and connection types of the pressure-taking pipeline shall meet the engineering design requirements. 2.1.4 Determine the fixing and support form of the field instrument. 2.1.5
The instrument construction and installation requirements shall meet the requirements of process control and the provisions of the instrument installation and use manual, as well as the various design provisions in the engineering project. 2.2
Control room and instrument panel
2.2.1 The reserved holes for the inlet of the control room shall be sealed, and the cable laying path shall reduce or avoid electrical "interference" as much as possible, and there shall be a reliable grounding system. Clarify the requirements for the equipment fixing method and construction installation procedures in the control room. 2.2.2
UPS should be placed in a separate room and an exhaust fan is required. 2.2.3
Determine the air inlet and outlet of the air conditioning system. Appropriate safety measures should be taken for control rooms and local instrument panels located in explosion-hazardous areas. 2.3 Alarm and interlock system
2.3.1 The on/off signal transmission of the alarm and interlock system shall not share a multi-pair cable with the general measurement signal transmission, and the precautions for the installation of the alarm and interlock equipment shall be clarified. 322
2.4 Flow
When using a throttling device to measure flow, specific provisions shall be made for the straight pipe section, the location of the pressure tapping port and the installation method of the transmitter, as well as the accessories and corresponding measures required for different process media. 2.4.2 For other types of flow meters, provisions shall be made for the accessories used and installation requirements. 2.5 Liquid level instrument
According to the different types of liquid level instruments selected in the specific project, determine the connection method and size of the instrument, and 2.5.12
should comply with the grade of the connected container.
2.6 Pressure and differential pressure instruments
2.6.1Similar to the requirements of Article 2.5.1 of this Regulation. 2.7 Temperature instrument
Thermometers or thermometer sleeves should clearly specify the installation method, installation location and issues that need attention. 2.8 Analytical instrument
2.8.1The installation requirements for the sampling system, sampling pretreatment system and analytical instrument room should be clearly defined. 2.8.2 For the electrical equipment of the analytical room in the explosion-hazardous area, corresponding explosion-proof measures should be taken. 2.9 Special instruments
2.9.1If special instruments such as weighing and radioactive instruments are used, clear regulations should be made according to the requirements of the product installation instructions and relevant laws and regulations.
2.10 Control valve
2.10.1 Different types of control valves should be selected in the project, and their installation requirements should be put forward respectively. 2.11 Power supply and gas source
2.11.1 According to the different requirements of the importance, reliability and continuity of the instrument and automation system in the production process, the load category of the instrument power supply should be clarified. The instrument power supply should be set independently. 2.11.2 The position of the air source of the instrument gas source should ensure the quality of the air and meet the requirements of the gas source quality. The outlet and material of the instrument gas source distribution pipe and branch pipe should also ensure that the instrument air is not polluted, and its specifications and dimensions should meet the requirements of the gas source pressure of the gas supply instrument.
2.12 Cables and pneumatic signal pipelines
2.12.1. There should be clear requirements for the laying of cables for various instruments, junction boxes, explosion-proof junction boxes and grounding of various instrument signal cables.
2.12.2 There should be clear requirements for the material, specifications and laying of pneumatic signal pipelines. Insulation and heating
2.13.1 The selection principles of electric heating or steam heating, insulation or heating, and the installation requirements of insulation and heating systems should be clarified.
3 Requirements for the preparation of instrument construction and installation requirements
Instrument construction and installation requirements are important design documents guiding construction and installation, so the text must be concise and clear. The adopted standards or specifications should be the current version, and the name, code and year of the standard should be indicated. 3.0.2
3.0.3 The conditions listed in the instrument construction and installation requirements are mandatory regulations, and words such as "recommendation" and "suggestion" shall not be used.
Appendix A Instrument construction and installation requirements (general) A.1 Overview
A.1.1 The construction and installation of instruments shall be carried out in accordance with the specific requirements of this document. A.1.2 Installation location of field instruments in chemical processes When installing instruments, the measuring pipeline should be as short as possible (except for high-temperature media such as superheated steam). The location and height of the instrument installation should be accessible through the ground and platform, walkway or fixed ladder to facilitate maintenance. If this cannot be done, temporary ladders will have to be used when necessary, but this situation should be avoided as much as possible. Handling of special situations
1 Pipeline vibration
In the case of severe pipeline vibration, measures should be taken to prevent the instrument from being affected by vibration. 1 Pressure point
When the differential pressure instrument is installed at the bottom pressure point or below the bottom pressure point, a three-valve group should generally be installed when measuring differential pressure: a two-valve group should be installed for differential pressure instruments measuring liquid level. Control valve
The handwheel on the control valve should be installed in a convenient location for operation 1 Instruments that need to be observed frequently (such as analyzers, recorders, etc.) These instruments should be installed in places that are convenient for observation and maintenance. A.1.3 Installation accessories
1 The type and grade of installation accessories should be selected according to the control operation conditions (refer to the instrument piping grade). 2 Process piping accessories (all instrument source components) should be provided by pipeline professionals, and the piping accessories should be of the same grade as the connected pipelines or equipment
A.1.4 Instrument measurement pipeline
1 The measurement pipeline between the pressure point and the instrument should generally use 12×1 or 14×2 stainless steel pipes. The pipeline measuring hydrogen or high pressure should use $14×3 or rainbow 4×4 pipelines. 2 Generally speaking, the material of the instrument measurement pipeline should be consistent with or better than the material of the connected pipeline or equipment.
3 Laying of measurement pipeline: When measuring gas, the measurement pipeline from the pressure point to the instrument should be inclined upward with a slope of at least 5%; when measuring liquid, the measurement pipeline from the pressure point to the instrument should be inclined downward with a slope of at least 5%. 4. The pipe fittings connected to the pressure point are usually welded parts. The connecting pipes between the measuring pipelines are generally of the type of butt welding, socket welding and ferrule.
A.1.5 Instrument brackets and columns
1 For instruments such as transmitters, converters, and field regulators, they should be installed on brackets or columns made of carbon steel. These brackets and columns can be made on site. 2 The instrument column is made of a steel plate as the base, a 2" (or 3\) pipe is welded on it as the column, and a reinforcement plate is welded at the bottom of the column. The upper end of the pipe is sealed. The length of the pipe should generally allow the instrument to be installed at a height of 1400mm from the ground or platform.
3 The instrument column should be fixed on the concrete floor, steel structure or pipeline (the latter should be avoided as much as possible). The instrument column is not allowed to be fixed on the pipeline of cold medium. A.2 Control room and instrument panel
A.2.1 Overview
1 The cable enters the control room through one or several reserved holes. When all the cables entering the control room are laid, these reserved holes should be isolated and sealed. 2 The paths for laying instrument cables and compensation cables for various purposes in the control room and cabinet room, and between the cabinet and the operating table should avoid electrical "interference". 3 Prevent rain, dust and process media from entering the control room. A.2.2 Control room equipment
1 Control room equipment includes instrument panels, boxes, DCS operating tables, DCS cabinets, terminal cabinets, etc. These equipment should be installed with movable and lifting trolleys as much as possible, and mechanical damage should be avoided during the installation and construction process. 2 It is strictly forbidden to use electric or gas welding to cut control room equipment. 3 The installation position and fixing method of control room equipment should comply with the relevant provisions of the design documents and GBJ93-86 specifications.
A.2.3 Construction and installation procedures for control room equipment 1 Consider the need for control room equipment to enter the control room. During the civil construction of the control room, a larger equipment entrance should be reserved at a certain door or window position. When the larger overall equipment of the control room enters the control room, the reserved entrance is repaired according to the civil construction design drawings of the control room. 2 When the control room adopts a movable floor structure, first determine the fixing position of the cabinet foundation channel steel, then arrange the cable laying in the control room, and finally install the movable floor. These three should be coordinated for construction. A.2.4 Power supply
Inverters, battery packs, etc. used for UPS (uninterruptible power supply), and DC power supplies should be placed in a separate room with an exhaust fan.
A.2.5 Air conditioning
The main control room and cabinet room should be air-conditioned. If a centralized air conditioner is selected, the air conditioner room should be located in a non-hazardous area. The vibration and noise generated should be isolated from the control operation room, and the air inlet and return air outlet positions of the air conditioning system should be adjusted. A.2.6 Grounding
All instrument systems should be grounded in accordance with the grounding criteria of the project. A.2.7 On-site instrument panel
The protection level of the on-site instrument panel installed outdoors is IP54 (minimum), the structure should be all-weather, meet the anti-corrosion requirements of the use environment, and be installed on a concrete foundation. The electrical equipment of the on-site panel should meet the requirements for the classification of electrical explosion hazard areas, and instrument air positive pressure ventilation safety measures should be taken when necessary. A.3 Alarm and interlock system
The installation of alarm and safety switches shall comply with the requirements of the corresponding parts of this regulation. A.3.1
A, 3.2 Signal cables from and to process units shall be laid in groups, but measurement signals for different purposes shall not share a multi-core cable or be placed in a protective tube. A.3.3 Avoid using "ordinary" wires as much as possible. A.3.4 Buttons for safety devices shall be installed in a convenient position for the operator and shall not be embedded (flush type). Buttons with covers or locks and red signs shall be selected to avoid misoperation. A.3.5 Emergency parking rotating alarm lights and horns shall be installed in conspicuous places at important on-site operating positions.
A.4 Flow
Throttling device
1 Straight section and piping
1) The installation of straight section and venturi tube for orifice plate measurement shall comply with the requirements of IS)5167. 2) The length of the straight pipe section used is generally based on d/D, or determined according to the d/D ratio of 0.7. 3) The throttling device is usually installed on a horizontal pipe. If it has to be installed in a vertical pipe section for maintenance convenience, the following principles should be observed:
- When measuring a two-phase flow of liquid or more liquid than gas, the flow direction of the fluid should be upward. Within the upstream and downstream straight pipe sections where the throttling device is installed, no connection ports such as thermometer sleeves, pressure pipes, sampling pipes, flushing pipes and discharge pipes are allowed (except for cleaning holes with dust and dirty gas).
2 Position of pressure tapping port
1) The position of the pressure tapping port of the throttling device on the horizontal pipe and its position on the circumference of the pipe cross section are shown in the figure below:
The measured fluid is a liquid
The measured fluid is a gas
2) The size of the flange pressure tapping hole is generally 1/2\NPT or ZG1/2\. The measured fluid is steam
a≤45°
3) For the measurement of liquid flow in buried pipelines, the liquid should fill the pipeline and the pressure tapping port should be at the top or middle of the pipeline. The pressure tapping ports on the high-pressure side and the low-pressure side should be on the same side of the pipeline as much as possible. 3 The transmitter should be installed as short as possible (except for high-temperature media such as superheated steam), and: - For gases and liquids that will vaporize at a temperature of 60°C or lower under operating pressure, the transmitter should be installed above the pressure tapping port (except for impossible situations). - For water vapor and liquids, the transmitter should be installed below the pressure tapping port (except for buried pipelines). When the liquid vaporizes at an operating pressure at a temperature between 60°C and -40°C, the measuring pipeline of the flowmeter must be heated. When the liquid has vaporized at an operating pressure at a temperature below -40°C, the measuring pipeline of the flowmeter does not need to be heated because it will absorb sufficient heat from the atmosphere to vaporize the liquid in the measuring pipeline. In both cases, the measuring pipeline should be higher than the pressure tapping hole to avoid the flow of vaporized gas. 4 Liquid seal
1) Liquid seal can be used in the following occasions:
Liquids that are easy to freeze
-Viscous liquid
-Corrosive media or places where there is a risk of accumulation. The latter two occasions should try to use diaphragm seal transmitters and other instruments. 2) For instruments used for force balance or small displacement, the liquid seal isolation method is to use a three-way isolation pipe instead of an isolation container.
5 Condensation tee or condensation container
Condensation tee is usually preferred. Unless it is used in superheated steam or high-temperature media, the measuring pipeline is short or a large displacement instrument is selected, in which case a condensation container is used. 6 Drain container
The drain container is used for wet gas and liquids containing easy sediments and is installed below the pressure tapping. 7 Vent container
The vent container is used to measure liquids and is installed above the pressure tapping. 8 Continuous purge
This system is only used in special occasions, such as very viscous media. 9 Valve groupbzxz.net
Two-valve group, three-valve group or five-valve group are usually used (refer to A.1.1). High-pressure measurement is excepted when the measuring medium contains particles, blockage and sedimentation. A.4.2 Rotor flowmeter
1 The rotor flowmeter should be installed upright on the vertical pipeline with the medium flowing upward. And the stress of the pipeline should not act on the instrument. The length of the straight pipe section on the upstream side should not be less than 5 times the inner diameter of the process pipeline. 2 The rotor flowmeter installed in the process should be installed on a bypass of the main line for easy maintenance and disassembly and equipped with:
One or two shut-off valves (gate valves) with the same diameter as the rotor flowmeter, and a shut-off valve (gate valve) is installed on the main line as a bypass of the rotor flowmeter.
Note: For glass rotor flowmeters, the shut-off valve should be a stop valve. If the medium flashes, a throttle valve is provided. The shut-off valve 3 installed upstream of the rotor flowmeter5 At important on-site operating positions, emergency parking rotating alarm lights and horns should be installed in conspicuous places.
A.4 Flow
Throttling device
1 Straight section and piping
1) The installation of the straight pipe section and the venturi tube for orifice plate measurement should comply with the requirements of IS)5167. 2) The length of the straight pipe section used is generally based on d/D, or determined according to the d/D ratio of 0.7. 3) The throttling device is usually installed on a horizontal pipeline. If it has to be installed in a vertical pipe section for the convenience of maintenance, the following principles should be observed:
- When measuring liquid or two-phase flow with more liquid than gas, the flow direction of the fluid should be upward. Within the upstream and downstream straight pipe sections where the throttling device is installed, there are no connections such as thermometer sleeves, pressure pipes, sampling pipes, flushing pipes and discharge pipes (except for cleaning holes with dust and dirty gas).
2 Pressure tapping port position
1) The position of the pressure tapping port of the throttling device on the horizontal pipeline and the position on the circumference of the pipeline cross section are shown in the figure below:
The measured fluid is liquid
The measured fluid is gas
2) The size of the flange pressure tapping hole is generally 1/2\NPT or ZG1/2\. The measured fluid is steam
a≤45°
3) For the measurement of liquid flow in buried pipelines, the liquid should fill the pipeline and the pressure tapping port should be at the top or middle of the pipeline. The pressure tapping ports on the high-pressure side and the low-pressure side should be on the same side of the pipeline as much as possible. 3 The transmitter should be installed as short as possible (except for high-temperature media such as superheated steam), and: 1 For gases and liquids that will vaporize at 60°C or lower at operating pressure, the transmitter should be installed above the pressure tapping port (except for impossible situations). 1 For water vapor and liquids, the transmitter should be installed below the pressure tapping port (except for buried pipelines). When the liquid vaporizes at the operating pressure and the temperature is between 60℃ and -40℃, the flow meter's measuring pipeline must be heated. When the liquid has vaporized at the operating pressure and the temperature is below -40℃, the flow meter's measuring pipeline does not need to be heated because it will absorb sufficient heat from the atmosphere to vaporize the liquid in the measuring pipeline. In both cases, the measuring pipeline should be higher than the pressure tapping hole to avoid the flow of vaporized gas. 4 Liquid seals
1) Liquid seals can be used in the following occasions:
Liquids that are easy to freeze
-Viscous liquids
-Corrosive media or occasions where there is a risk of accumulation. The latter two occasions should try to use diaphragm seal transmitters and other instruments. 2) For instruments with force balance or small displacement, the liquid seal isolation method is to use a three-way isolation pipe instead of an isolation container.
5 Condensation tee or condensation container
Condensation tee is usually preferred. Unless it is used for superheated steam or high-temperature media, the measuring pipeline is short or a large displacement instrument is selected, a condensation container is used. 6 Drain container
The drain container is used for wet gas and liquids containing easy sediments, and is installed below the pressure port. 7 Vent container
The vent container is used to measure liquids and is installed above the pressure port. 8 Continuous purge
This system is only used in special occasions, such as very viscous media. 9 Valve group
Usually two-valve group and three-valve group or five-valve group are used (refer to A.1.1). High-pressure measurement, except when the measuring medium contains particles, blockage and sediment. A.4.2 Rotor flowmeter
1 The rotor flowmeter should be installed upright on the vertical pipeline, and the medium flows upward. And the stress of the pipeline should not act on the instrument. The length of the upstream straight pipe section should not be less than 5 times the inner diameter of the process pipeline. 2 For the convenience of maintenance and disassembly, the rotor flowmeter installed in the process should be installed on a bypass of the main line and equipped with:
One or two cut-off valves (gate valves) with the same diameter as the rotor flowmeter, and a cut-off valve (gate valve) should be installed on the main line as a bypass of the rotor flowmeter.
Note: For glass rotor flowmeters, the cut-off valve should be a stop valve. If the medium has flash evaporation, a throttle valve should be provided. The cut-off valve 3 installed upstream of the rotor flowmeter5 At important on-site operating positions, emergency parking rotating alarm lights and horns should be installed in conspicuous places.
A.4 Flow
Throttling device
1 Straight section and piping
1) The installation of the straight pipe section and the venturi tube for orifice plate measurement should comply with the requirements of IS)5167. 2) The length of the straight pipe section used is generally based on d/D, or determined according to the d/D ratio of 0.7. 3) The throttling device is usually installed on a horizontal pipeline. If it has to be installed in a vertical pipe section for the convenience of maintenance, the following principles should be observed:
- When measuring liquid or two-phase flow with more liquid than gas, the flow direction of the fluid should be upward. Within the upstream and downstream straight pipe sections where the throttling device is installed, there are no connections such as thermometer sleeves, pressure pipes, sampling pipes, flushing pipes and discharge pipes (except for cleaning holes with dust and dirty gas).
2 Pressure tapping port position
1) The position of the pressure tapping port of the throttling device on the horizontal pipeline and the position on the circumference of the pipeline cross section are shown in the figure below:
The measured fluid is liquid
The measured fluid is gas
2) The size of the flange pressure tapping hole is generally 1/2\NPT or ZG1/2\. The measured fluid is steam
a≤45°
3) For the measurement of liquid flow in buried pipelines, the liquid should fill the pipeline and the pressure tapping port should be at the top or middle of the pipeline. The pressure tapping ports on the high-pressure side and the low-pressure side should be on the same side of the pipeline as much as possible. 3 The transmitter should be installed as short as possible (except for high-temperature media such as superheated steam), and: 1 For gases and liquids that will vaporize at 60°C or lower at operating pressure, the transmitter should be installed above the pressure tapping port (except for impossible situations). 1 For water vapor and liquids, the transmitter should be installed below the pressure tapping port (except for buried pipelines). When the liquid vaporizes at the operating pressure and the temperature is between 60℃ and -40℃, the flow meter's measuring pipeline must be heated. When the liquid has vaporized at the operating pressure and the temperature is below -40℃, the flow meter's measuring pipeline does not need to be heated because it will absorb sufficient heat from the atmosphere to vaporize the liquid in the measuring pipeline. In both cases, the measuring pipeline should be higher than the pressure tapping hole to avoid the flow of vaporized gas. 4 Liquid seals
1) Liquid seals can be used in the following occasions:
Liquids that are easy to freeze
-Viscous liquids
-Corrosive media or occasions where there is a risk of accumulation. The latter two occasions should try to use diaphragm seal transmitters and other instruments. 2) For instruments with force balance or small displacement, the liquid seal isolation method is to use a three-way isolation pipe instead of an isolation container.
5 Condensation tee or condensation container
Condensation tee is usually preferred. Unless it is used for superheated steam or high-temperature media, the measuring pipeline is short or a large displacement instrument is selected, a condensation container is used. 6 Drain container
The drain container is used for wet gas and liquids containing easy sediments, and is installed below the pressure port. 7 Vent container
The vent container is used to measure liquids and is installed above the pressure port. 8 Continuous purge
This system is only used in special occasions, such as very viscous media. 9 Valve group
Usually two-valve group and three-valve group or five-valve group are used (refer to A.1.1). High-pressure measurement, except when the measuring medium contains particles, blockage and sediment. A.4.2 Rotor flowmeter
1 The rotor flowmeter should be installed upright on the vertical pipeline, and the medium flows upward. And the stress of the pipeline should not act on the instrument. The length of the upstream straight pipe section should not be less than 5 times the inner diameter of the process pipeline. 2 For the convenience of maintenance and disassembly, the rotor flowmeter installed in the process should be installed on a bypass of the main line and equipped with:
One or two cut-off valves (gate valves) with the same diameter as the rotor flowmeter, and a cut-off valve (gate valve) should be installed on the main line as a bypass of the rotor flowmeter.
Note: For glass rotor flowmeters, the cut-off valve should be a stop valve. If the medium has flash evaporation, a throttle valve should be provided. The cut-off valve 3 installed upstream of the rotor flowmeter
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