How to draw a single line diagram of process flow? Kneel for answers.

3.3.5 In the flow chart and system diagram, the graphic symbols of commonly used equipment shall comply with the provisions in Table 3.3.5.

3.3.6 The graphic symbols of common pipe fittings and other accessories shall comply with the provisions in Table 3.3.6.

3.3.7 The graphic compliance of common valve and pipeline connection modes shall comply with the provisions in Table 3.3.7.

3.3.8 The graphic symbols of ordinary pipe supports, pipe supports and hangers shall comply with the provisions in Table 3.3.8.

3.3.9 Graphical symbols of commonly used testing and measuring instruments shall comply with the provisions in Table 3.3.9.

3.3. 10 Graphical symbols of commonly used equipment in user engineering shall comply with the provisions in Table 3.3. 10.

4 Drawing Contents and Drawing Methods 4. 1 General Provisions 4. 1. 1 The design drawings of each design stage of gas engineering shall meet the corresponding design depth requirements. 4. 1.2 Drawing should highlight key points, be symmetrical and choose a reasonable proportion. For the content that can be clearly expressed by drawings and graphic symbols, it is not appropriate to use text description. Problems related to the whole project should be explained on the home page, and local problems should be indicated in the corresponding drawings.

4. 1.3 The marking method of drawing name shall meet the following requirements: 1 When there is only one drawing in a drawing, the drawing name can be marked in the title bar; 2. When there are two or more drawings in a picture, their names should be marked, and the names should be marked at the bottom and center of the drawings. 4. 1.4 The layout of drawings shall meet the following requirements: 1 When two or more drawings are arranged in a drawing, the drawing shall be made according to the principle that the plan is at the bottom, the front section is at the top, and the side section, flow chart, piping system diagram or detailed drawing is at the right; 2 When two or more floor plans are arranged in a picture, they should be drawn according to the sequence of process flow or the principle that the lower floor plan is above the lower floor plan and the upper floor plan; The description of the pattern should be arranged on the right or below the figure. 4. 1.5 In the same set of engineering design drawings, the drawing methods of line widths, legends, terms and symbols should be consistent. 4. 1.6 The list of equipment and materials shall include such columns as equipment name, specification, quantity and remarks; The list of pipeline materials shall include serial number (or number), material name, specification (or physical performance), quantity, unit number and remarks. 4. The text description of 1 .7 drawings shall be written in the form of "Note:" or "Note:" or "Description:" and numbered as "1,2,3 ...". 4. 1.8 The sketch shall meet the following requirements: 1 Two or more identical figures or patterns, one of which can be drawn and the others can be drawn as sketches; You can draw two or more graphics or patterns with similar shapes and different sizes, and others can simplify drawing, but the sizes should be clearly marked.

4.2 Drawing content and drawing method 4.2. 1 The drawing of process flow chart of natural gas plant and station shall meet the following requirements: 1 The process flow chart shall be drawn in a single line, but not to scale. Among them, the gas pipeline should adopt thick solid line, other pipelines should adopt middle line (solid line, dotted line and dotted line), and the outline of equipment wheel should adopt thin solid line. 2. The process flow chart shall draw the relative relationship among process devices, equipment and pipelines in the natural gas plant and station, as well as the process sequence. When drawing the process flow chart with control points, it should also comply with the provisions of automatic control professional drawing. The process flow chart shall draw all the process equipment and indicate the equipment number or name. Process equipment should be drawn with thin solid lines or represented with graphic symbols according to the shape of the equipment. 4 The process flow chart shall draw all process pipelines and necessary public pipelines. According to the different depth requirements of each design stage, the process pipeline shall be marked with pipeline number, pipeline specification and medium flow direction, and the public pipeline shall be marked with medium name, flow direction and necessary parameters. 5 Pipeline accessories such as valves on pipelines should be drawn, but pipeline joints are not included. 6 Interface orientation between pipeline and equipment should be consistent with the actual situation. 7 Pipeline shall be drawn horizontally and vertically, and diagonal lines shall not be used. The pipeline shall not cross the equipment drawing to reduce the pipeline crossing; When there is intersection, the main pipeline should be connected and the secondary pipeline can be disconnected. 8 When there are two or more identical systems, the process flow chart of only one system can be drawn, and the same equipment and corresponding valves of other systems can be omitted, but the connected branch pipes should be indicated, and the equipment number should be indicated. 4.2.2 The general layout of natural gas plants and stations shall meet the following requirements:

1 The outline of the building (structure) within the factory station fence, the scope of the device area and the outline of the equipment inside and outside the device area shall be drawn; The general plan of the engineering design stage should be drawn on the basis of the actual topographic map, and the buildings (structures) and landforms adjacent to the gas plant and station should be clearly marked. You should draw a compass or a wind rose diagram. 2 The buildings (structures) in the drawing shall be marked with numbers or design items. The list of buildings (structures) should be given by the semicolon of the corresponding number or design item; The number of floors, floor area, building area and structural form of each building (structure) should be indicated in the table. 3 The horizontal clear distance between buildings (structures) with explosion danger and other buildings (structures) inside and outside the plant station should be indicated in the drawing. 4 The drawings shall indicate the four-corner coordinates, installation area and land requisition red line of the factory and station fence and buildings (structures); The center coordinates of equipment located outdoors and outside the device area shall be marked. 5. In the figure, the thick solid line indicates the new building (structure), the thick dotted line indicates the reserved building (structure), and the thin solid line indicates the original building (structure). 6. The drawings shall indicate the main technical indicators such as the area occupied by the plant and station, building area, building area, building coefficient, greening coefficient, fence length, road area and return area. 4.2.3 The drawing of equipment and pipeline installation drawings in natural gas plants and stations shall meet the following requirements: 1 The equipment and pipeline installation drawings shall be designed according to the semi-colon of design items. The installation drawing shall include plan, section and section. 2 Equipment and pipeline installation plan shall be drawn according to the architectural plan, structural plan or general plan of design items. The outline and pipeline of gas process equipment in the design sub-item shall be drawn, and the positioning dimensions of equipment and pipeline installation shall be given. According to the building,

Use icons to indicate the axis number and main dimensions of buildings (structures), and draw walls, doors, windows, columns, stairs and operating platforms. This plan should be drawn with a compass or a wind rose diagram. 3 When the location cannot be clearly indicated on the floor plan, the sectional view or sectional view of equipment and pipeline installation shall be drawn. The profile and profile shall draw the outer contour lines and pipelines of buildings (structures) and equipment visible in the projection direction of the profile, and shall indicate the positioning dimensions and elevation of equipment and pipeline installation. 4 The pipeline number in the installation drawing should be consistent with the pipeline number in the flow chart, and marked above or on the left side of the pipeline; The thin solid line can also be used to lead out the blank space, indicating the pipeline number, specification, material, conveying medium, etc. 5 The outline of the equipment in the installation drawing shall be drawn with thin solid lines. The equipment number should be consistent with the equipment list; When the equipment has an operating platform, the elevation of the operating platform should also be marked. 6 The list of equipment shall be given in the installation drawing, and the list shall indicate the serial number, name, specifications, process parameters, materials, quantity, processing drawing or general Tu Tu number, current relevant national selection standards, etc. 7 In the installation drawing, a thick solid line should be drawn for pipes with a diameter less than 300mm, two thick solid lines should be drawn for pipes with a diameter greater than or equal to 300mm, and two thin solid lines should be drawn for flanges. Buried pipelines are drawn with thick dashed lines, pipelines in ditches are drawn with single thick solid lines, and ditches are drawn with thin solid lines. 8 The elevation of process pipeline shall be given in the installation drawing, and the slope, slope direction and medium flow direction shall be indicated. 9 The support and hanger of the pipeline shall be drawn in the installation drawing, and the positioning size and number shall be given. The general plan and tank farm supports shall list the supports, giving the center coordinates, pipeline elevation and supports.

Top elevation, ground elevation, support length, etc. 10 plan shall be marked with the positioning coordinates of buildings (structures) and the positioning dimensions of equipment foundation. When there is a storage tank area, the four-corner coordinates of the breakwater shall be marked. 1 1 Equipment installation height, equipment foundation height, and equipment inlet and outlet pipeline elevation shall be marked in the profile and cross-sectional views. The diagram should show the direction and height changes of pipeline turning and crossing. 12 for non-standard equipment, the nozzle orientation diagram shall be drawn, and the nozzle table shall be listed, indicating the pressure grade, connection mode and purpose of the nozzle. 13 pipelines connected with other design sub-items shall be marked with semicolons and drawing numbers of sub-items. When the pipeline exceeds the diagram in this drawing, the drawing number of the continuation drawing shall be indicated. 4.2.4 The drawing of gas pipeline construction drawings in residential areas and courtyards shall comply with the following provisions: 1 The residential areas and courtyards shall draw gas pipeline layout plans, but the longitudinal section of the pipelines is not required. When the residential area is large, a location map should be drawn to identify the gas pipeline area. The plan of gas pipeline should be based on the plan construction drawing, completion drawing or actual surveying and mapping topographic map of residential area and courtyard. The topography, landforms, roads and all buildings (structures) in the drawing shall be drawn with thin lines. The name of the building (structure) and the road should be marked, and the number of floors should be marked for multi-storey buildings, and an arrow pointing north should be drawn. 3. Low and medium pressure gas pipelines, pressure regulating stations, pressure regulating boxes, valves, condensation water tanks, drainage pipes, etc. in the plan. It should be drawn, and the gas pipeline should be drawn with thick solid lines. The location and size of gas pipeline should be given in the plan. 5 The specification, length, slope and elevation of the gas pipeline shall be indicated in the plan.

6 The specification and quantity of pressure regulating station, pressure regulating box, valve, condensate tank, drainage pipe and pipeline accessories shall be indicated in the plan of gas pipeline, and the positioning dimensions shall be given. 7 Where the floor plan cannot be clearly expressed, local details should be drawn. Local details may not be drawn to scale. 8. Other pipelines adjacent to or crossing the gas pipeline shall be drawn in the plan, and the relative positions of the gas pipeline and other pipelines shall be indicated. 4.2.5 The indoor gas pipeline construction drawing shall meet the following requirements: 1 The indoor gas pipeline construction drawing shall draw the plan and system diagram. When the layout of pipelines and equipment is complicated and the system diagram cannot be clearly expressed, it is advisable to supplement the section diagram. The plan of indoor gas pipeline shall be based on the plan construction drawing, completion drawing or actual surveying and mapping plan of the building. The plan should be drawn by orthographic projection method. The exposed gas pipeline shall be painted with thick solid lines; Thick dotted lines should be drawn for buried or buried gas pipelines in the wall; The buildings in the picture should be drawn with thin lines. 3 gas pipelines, gas meters, voltage regulators, valves, gas appliances, etc. Should be drawn in the plan. 4 The relative position and diameter of gas pipeline in the plan should be clearly marked. 5. The system diagram should be drawn by 45 orthographic axonometric drawing. The layout direction of the system diagram should be consistent with the plan, and should be drawn in proportion; When the local pipeline cannot be clearly expressed by scale, the scale can be omitted. 6 gas pipelines, gas meters, regulators, valves, pipe fittings, etc. Should be drawn in the system diagram, and indicate the specifications. 7 The elevation and slope of indoor gas pipeline shall be indicated in the system diagram. 8. Detailed drawings shall be drawn for the connection between indoor gas equipment and household pipelines.

4.2.6 The layout of high-pressure transmission and distribution pipelines and medium and low-pressure transmission and distribution networks shall meet the following requirements: 1 The layout of high-pressure transmission and distribution pipelines and medium and low-pressure transmission and distribution networks shall be drawn on the basis of existing topographic maps, road maps and planning maps. The topography, landforms, roads and all buildings (structures) in the map should be drawn with thin lines and a compass. The position of each plant and station, the pipeline direction and the pipe diameter shall be indicated on the drawings. According to the requirements of different depths in the design stage, the position of the valve on the pipeline should be marked. 3 Gas pipelines shall be drawn with thick lines (solid lines, dashed lines and dotted lines). When drawing a color map, different colors of the same line type can be used to distinguish gas pipelines with different pressure grades or different construction stages. The names of main roads, rivers, blocks and villages and towns should be marked in the drawing. 4.2.7 The drawing of the plane construction drawing of high, medium and low pressure gas transmission and distribution pipelines shall meet the following requirements: 1 The plane construction drawing of high, medium and low pressure gas transmission and distribution pipelines shall be based on the measured strip topographic map or road plane construction drawing and completion drawing along the gas pipeline. The topography, landforms, roads and all buildings (structures) in the drawing should be drawn with thin lines and arrows pointing north. 2. It is recommended to use paper with format code A2 or extended size A2. The gas pipeline and other pipelines adjacent to and intersecting with it should be drawn in the drawing. Gas pipelines are drawn with thick solid lines and single lines, while other pipelines are drawn with thin solid lines, thin dashed lines or thin dashed lines. 4 The positioning dimensions of the gas pipeline shall be indicated in the drawing, including the starting point, ending point and turning point of the pipeline.

Important control points should be marked with coordinates; When the pipeline is laid elastically in the plane, the relevant parameters of the elastic laying curve should be given. 5 The specification of gas pipeline shall be indicated in the drawing, and the names and specifications of other pipelines shall be indicated. 6 The condensate tank, drain pipe, valve and pipeline accessories shall be drawn in the drawing, and the specifications, numbers, anti-corrosion grades and practices shall be indicated. 7 When the tee joint, bend, etc. in the drawing cannot be clearly expressed, local details should be drawn. 8 The pipeline mileage pile shall be drawn in the drawing to indicate the mileage. Mileage piles shall be represented by a thin solid line with a length of 3mm perpendicular to the gas pipeline. 9 In the drawing, the turning point of the pipeline plane should be marked with the degree of rotation. 10 The position and scope of pipeline counterweight stability, pipeline anchorage and pipeline hydraulic protection shall be drawn, and the practical explanation shall be given. 1 1 For the pipeline crossing project with directional drilling, it is advisable to draw the working site range of the pipeline entering and exiting; For overhead pipelines, pipe supports shall be drawn, and the forms and quantities of supports and supports shall be given. 12 when the plan contains less content, it can be incorporated into the longitudinal section of gas transmission and distribution pipeline as a schematic diagram of the pipeline. 13 When two gas pipelines are laid in parallel in the same trench, they should be designed separately. The designed gas pipelines are represented by thick solid lines, and the parallel gas pipelines are represented by dotted lines. 4.2.8 The drawing of the longitudinal section construction drawing of high, medium and low pressure gas transmission and distribution pipelines shall comply with the following provisions: 1 The longitudinal section construction drawing of high, medium and low pressure gas transmission and distribution pipelines shall be based on the measured topographic longitudinal section or road longitudinal section construction drawing and completion drawing along the gas pipeline.

System. 2. It is suggested to adopt the format code A2 or A2 with extended size. 3 Corresponding to the elevation scale, the current ground line, design ground line, gas pipeline and other pipelines crossing the pipeline route should be drawn. Water level lines should be drawn when crossing rivers, ditches and ponds with water. Gas pipelines should be drawn with medium and thick solid lines and double lines. Current ground wire and other pipelines should be drawn with thin solid lines; The design grounding wire shall be drawn with thin dashed lines. 4. The schematic plan of gas pipeline should be drawn. 5 Mileage piles in the corresponding plan shall indicate the pipeline mileage, original ground elevation, design ground elevation, design pipe bottom elevation, trench excavation depth, pipeline slope, etc. 6 When the pipeline is laid longitudinally elastically, the relevant parameters of the elastic laying curve shall be indicated on the drawing. 7 condensate tank, drain pipe, valve, tee, etc. Should be drawn on the drawings, and indicate the specifications and numbers. 8 The position and scope of pipeline counterweight stability, pipeline anchoring, pipeline hydraulic protection and casing protection should be drawn, and the practical description and related details should be given. For the pipeline crossing project with directional drilling, the soil geological conditions of the crossing section should be drawn in the longitudinal section of the pipeline. For overhead pipelines, pipe supports should be drawn, and the forms, quantities and practices of supports and supports should be given. 10 shall indicate the material, specification, anticorrosion grade and practice of the pipeline. 1 1 The soil resistivity along the pipeline and the earthwork volume for pipeline construction shall be indicated. 12 The vertical or spatial corner of the pipeline in the drawing shall be marked with the angle and elbow specification. 13 For pipes laid by pipe jacking or casing, the pipe bottom of casing shall be marked.

Altitude. 14 shall indicate the positions and related parameters of other pipelines and obstacles crossing the gas pipeline. Description of words in this standard 1 In order to facilitate different treatment when implementing the provisions of this standard, the description of words with different strict requirements is as follows: 1) It is very strict, and it must be done: "must" is used for affirmative words and "forbidden" is used for negative words; 2) Strictly speaking, this should be done under normal circumstances: positive words should be used, negative words should not be used or not; 3) If a slight choice is allowed, do it first if conditions permit: the positive word "appropriate" and the negative word "unfavorable"; 4) If you have a choice and can do it under certain conditions, use "can". 2 The wording of the provisions that should be implemented according to other relevant standards is "should comply with the provisions of GB/T 500060".

Description: CJJ gas engineering drawing standard /T 130—2009 was approved by the Ministry of Housing and Urban-Rural Development.

Announcement No.345 of July 8, 2009 was approved for release. In the process of standard formulation, the compilation team studied the traditional drawing methods of gas specialty, and combined with engineering practice, referred to the drawing standards of other industries in China, and stipulated various requirements of gas engineering drawing. In order to facilitate the relevant personnel of design, construction, scientific research, schools and other units to correctly understand and implement the provisions when using this standard, the drafting group of gas engineering drafting standards has compiled the provisions of this standard in the order of chapter, section and article, and explained the purpose, basis and relevant matters needing attention of the implementation of the provisions. However, the explanation of this article does not have the same legal effect as the standard text, and is only for users to understand and master the standard provisions. 1 General 1.0. 1 The principle of compiling this standard is to harmonize with the current relevant national standards as much as possible, and give due consideration to the drawing regulations and habits used for many years, so as to facilitate operation and management according to the characteristics of gas engineering. 1.0.2 This standard is also applicable to the actual surveying and mapping of the original gas facilities in the reconstruction and expansion project. 1.0.4 this standard only stipulates the basic requirements of urban gas engineering drawing, and it is impossible to cover all the professional contents appearing in the project. Therefore, when the content of professional drawing is not specified in this standard, the current national standard should be implemented. 2. Basic provisions for drawing 2. 1 sheet 2. 1. 1 sheet format and size shall conform to the national standard "Unified Standard for Architectural Drawing"

The provisions in section 2. 1 in GB/T 5000 1—200 1 are consistent. This standard does not specify the size and format of the title bar, and users can determine it by themselves according to the actual situation. 2. The size expansion of1.2 is proposed when the basic format size can't meet the requirements, and the expansion size is an integer multiple to facilitate memory and ensure the unification of drawing specifications. The lengthened long side dimension is consistent with the current national standard "Technical Drawing". 2.2 Arrangement order of drawings 2.2. 1 ~ 2.2.2 The arrangement order of drawings is specified according to the type and specialty. 2.3 Drawing lines 2.3. 1 The purpose of this standard is to make the drawing clear, and there is no mandatory combination of line widths. According to the category, scale and complexity of drawings, users can follow the national standard GB/T50001-2001. When the drawing format is large, you can choose a larger b value; When the graph lines are dense, you can choose a smaller b value. For example, the figure of gas pipeline planning and feasibility study can choose a larger B value. 2.3.3 The following factors should be considered in the selection of common line types: 1 When drawing equipment plan and section respectively, the equipment should be the main content, and the outline lines should be thick. In the plan and profile of equipment and pipeline, firstly highlight the pipeline and use thick lines; Secondly, highlight the equipment and use the center line. Whether the pipeline is represented by single line or double line, the principle of clear expression and beautiful and balanced drawing should be followed. 2.4 format and specification of scale drawing)) GB/T 14689.

2.4.2 The provisions of this standard on marking different scales in the vertical and horizontal directions of the same drawing are consistent with the requirements of the national standard Technical Drawing Scale GB/T 14690-93.

The choice of specific proportion is based on the principle of expressing intention, which should not be too large or too small. 2.4.5 In engineering drawing, priority should be given to the commonly used proportions listed in Table 2.4.5. The proportion of the general plan of gas pipeline network can be determined according to the proportion of topographic map or planning map of each town. 2.5 font 2.5. 1 Chinese characters adopt long imitation song style, which is GB/T 1469 1 and other countries.

Standard terms. Chinese characters, Latin letters, Greek letters and Arabic numerals; The writing method of the horse number shall conform to the relevant provisions in Chapter 4 of the National Standard "Unified Standard for Architectural Drawing" GB/T50001-200/KLOC-0. 2.6 The requirement of dimensioning 2.6.3 "One drawing should use start and stop symbols" conforms to the national standard Mechanical Drawing and the national standard Mechanical Engineering CAD Drawing Rules GB/T 14665- 1998. Short diagonal lines are bold, and arrows are solid arrows, which are more eye-catching. 2.6.6 The direction of the dimension numbers shall be marked as per Figure 1. If the size number is within the 30 diagonal area, it should be written in the form of Figure 2.

2.7 Diameter and pipeline slope 2.7.2 This marking method is mainly applicable to preliminary design, construction drawing and completion drawing, and the nominal diameter can also be used in other design stages. 2.8 elevation 2.8. 1 elevation marking is based on the principle of clearly expressing the elevation changes of buildings and pipelines, and does not need to be marked too much. According to the current national standard GB/T 5000 1, the height of the isosceles triangle of the elevation symbol should be (2.5 ~ 5.0) mm..2.9No. of equipment and pipelines 2.9. 1 The numbering method specified in this article is not only applicable to equipment and components, but also applicable to other situations requiring numbering in town gas drawings, such as the numbering of pipeline accessories and pipeline facilities. 2.9.2 According to needs, the diameter of the circle used for numbering marks can also be increased, and the thick solid line can be lengthened. 2. 10 section symbol 2. 10. 1 The length of section position line and section direction line can be adjusted according to the view size. 3 Common codes and graphic symbols 3. 1 general provisions 3. 1.2 Codes and graphic symbols used in a set of drawings can be placed in the general description on the front page of the drawing or in the main drawing of related drawings respectively. 3.2 Pipeline Code 3.2. 1 Pipeline code generally comes from the prefix of English name, which can indicate the medium transported by pipeline.

Different parameters and pipeline uses; Try to use one letter in the pipeline code; when using one letter causes confusion, you can add letters; 3.2. 1 lists the codes of pipes and instruments commonly used in gas engineering. Table 1 is the English name of some common pipeline codes. Table 1 English name sequence of common pipeline codes 1 2 3 4 5 6 7 liquefied natural gas liquid pipeline 8 liquefied petroleum gas liquid pipeline 9 liquefied petroleum gas liquid pipeline 10 liquefied petroleum gas mixed air1/ Liquefied petroleum gas air pipeline LPGL ph. ASE pipeline lpg mixed LPGV phase pipeline lpg liquid LNGL phase pipeline lpg vapor gas pipeline (general) high-pressure gas pipeline, medium-pressure gas pipeline, low-pressure natural gas pipeline, compressed natural gas pipeline and liquefied natural gas gas phase pipeline. G Hg mg LG NG CNG natural gas pipeline high pressure natural gas pipeline medium pressure gas pipeline low pressure natural gas pipeline compressed natural gas pipeline liquefied natural gas pipeline.

12 13 14 15 16 17

Artificial gas pipeline, oil supply pipeline, compressed air pipeline, water supply pipeline, hot water pipeline and radiation pipeline.

Mr. O A

Artificial gas pipeline, oil supply pipeline, compressed air pipeline, water supply pipeline, hot water pipeline and ventilation pipeline.

3.3 Graphical Symbols 3.3. 1 Table 3.3. 1 Graphical symbols commonly used in power plants and stations are formulated according to the drawing habits of gas engineering in China and the principles of simplicity, image and easy drawing. 3.3.4 ~ 3.3. 10 The graphic symbols in tables 3.3.4 and 3.3.5 are often used in the system diagram and flow chart of gas engineering. In order to reduce the workload of drawing and facilitate computer drawing, try not to use or use less black graphic symbols. Graphical symbols of equipment, instruments and meters with various forms and complicated shapes are generally simplified according to their shapes. 4. Drawing content and drawing method 4. 1 general provisions 4.1.1~ 4.1.8 specifies the drawing depth requirements and general requirements in each stage of gas engineering. 4.2 Drawing Content and Drawing Method 4.2. 1 This article specifies the drawing method of process flow chart of natural gas plants and stations. The process flow chart can not be drawn to scale, which does not reflect the spatial relative position of equipment and pipelines, but mainly reflects the composition of the process system, the relationship between each component and the process sequence of each link; Single-line diagram should be adopted, and the interface orientation between pipeline and equipment can be roughly consistent with the actual situation.

Marking the numbers or names of all process equipment in the process flow chart can directly reflect the composition of the process system. "Process equipment is drawn with thin solid lines or represented with graphic symbols according to the shape of the equipment" can further clarify the characteristics and functions of process equipment. 5 ~ 6 Because the process pipelines of gas storage station, liquefied petroleum gas cylinder filling station, gasification station, gate station and pressure regulating station are relatively complex, the pipe number, pipe diameter and flow direction are marked on the pipelines, and the interface orientation and valve arrangement order of all valves, fittings, pipelines and equipment are drawn, which is convenient to intuitively reflect the working principle of the system and the relationship between components. The connectors of the pipeline refer to: flanges, tees, bends, etc. 4.2.2 This article specifies the drawing method of the general plan of natural gas plants and stations. Including the content, alignment and positioning requirements of the plan. 4.2.4 This article specifies the drawing method of gas pipeline construction drawing in residential areas and courtyards. 1 The purpose of drawing the gas pipeline layout is to determine the plane position of the gas pipeline and its relative relationship with various buildings. The underground pipe network in residential area is complex, and there is generally no comprehensive longitudinal pipe map. Therefore, the vertical pipeline diagram can be omitted from the gas pipeline construction drawings of residential areas and courtyards. In the layout of gas pipeline, the topography, landforms, roads and all buildings are drawn with thin lines, which can more clearly reflect the plane position of gas pipeline. 3 ~ 5 Residential and courtyard gas pipeline construction drawings cannot draw the pipeline longitudinal section, therefore, parameters such as pipe diameter, slope, pipeline length, elevation or buried depth should be indicated in the plan. 4.2.5 This article specifies the drawing requirements of indoor gas pipeline construction drawing. Indoor gas pipeline construction drawing includes floor plan and system diagram (axonometric drawing). The plan is drawn by orthographic method, and the building outline on the plan is drawn by the building plan.

The relative position and diameter of the pipeline shall be indicated; The system diagram should be drawn according to the 45 orthographic axonometric method. Valves, gas meters and other equipment and fittings such as tees and bends should be drawn in the drawing, and the diameter, elevation and slope of indoor gas pipeline should be marked to meet the requirements of construction and installation. Articles 4.2.7 ~ 4.2.8 stipulate the drawing methods and depth requirements for the plane and longitudinal section construction drawings of high-,medium-and low-pressure gas transmission and distribution pipelines.

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