. Pipeline series standard
In the design and construction of pressure pipeline, the selection of standard series of pressure pipeline and its components should be considered first. Although there are many calibration systems used around the world, they can be roughly divided into two categories. See Table 3 for pressure piping standards. See Table 4 for flange standards.
Table 3 Standard Classification of Pressure Piping
Specifications for large and small outer diameter series
DN- nominal diameter Ф-outside diameter
Dn15-Ф 22mm, DN20-Ф 27mm, DN25-Ф 34mm, DN32-Ф 42mm, DN40-Ф 48mm, DN50-Ф 60mm.
DN65-Ф 76 (73) mm, DN80-Ф 89mm DN/KOOC-0/00-Ф/KOOC-0/4mm, DN/KOOC-0/25-Ф/KOOC-0/40mm DN/KOOC-0/50-Ф/KOOC.
DN 15-ф 18mm，DN20-ф25mm DN25-ф32mm，DN32-ф38mm DN40-ф45mm，DN50-ф57mm DN65-ф73mm，DN80-ф89mm
DN 100-ф 108mm、dn 125-ф 133mm dn 150-ф 159mm、DN200-ф2 19mm DN250-ф273mm、DN300-ф325mm DN350-ф37
What does 1/2 3/4 1, 12 16 2025 of pipe fittings stand for?
1/2, 3/4 and 1 are the nominal diameters in the pipeline standard, which are commonly known as the names of half-inch or 4-minute, 6-minute and 1 inch pipes or fittings, such as 4-branch pipes and 4-branch bends, which are mostly used for water pipes.
1216,2025 refers to the internal diameter and external meridian of the customs, in millimeters. example
12/ 16 is a pipe with an inner diameter of 12mm and an outer diameter of 16mm. Mostly used in plastic pipes. 1/2, 3/4, 1 are British sizes, each inch =25.4 mm, which are commonly used on steel pipes.
1216,2025 means "inner diameter and outer diameter" (inner diameter 12MM, outer diameter 16MM), which is often used for aluminum-plastic pipes and steel-plastic pipes.
How many kinds of fittings are connected?
G 1/4, G 1/8 are pipe threads, 1/4 and 1/8 inches.
The pipe joint has pipe thread, taper thread, R thread, etc. Connection methods include welding, flaring, quick insertion, taper sleeve, etc.
How to express the steel pipe?
If the steel pipe you are talking about is a water and gas transmission steel pipe, then its expression is: the nominal diameter refers to the inner diameter. The unit is millimeters or inches. [For example, φ25 water pipe. Refers to the steel pipe with a nominal diameter (inner diameter) of φ25mm (or one inch).
If it is seamless steel pipe or welded steel pipe, its expression is: Nominal diameter refers to external diameter (external diameter × wall thickness). The unit is millimeters. [For example, φ32×3 seamless steel pipe. Refers to the seamless steel pipe with a nominal diameter (outer diameter) of φ 32mm and a wall thickness of 3mm.
What is the nominal diameter?
Nominal diameter is the size of all pipeline accessories in the pipeline system, expressed in numbers. Nominal diameter is a circular integer for easy reference, which has only a loose relationship with machining size. The nominal diameter is marked with the letter "DN" followed by a number.
Nominal diameter, also known as average outer diameter.
This is because the wall of the metal tube is very thin, and the outer diameter and inner diameter of the tube are almost the same, so the average of the outer diameter and inner diameter of the tube is taken as the pipe diameter.
DN is the nominal diameter, nominal diameter (or nominal diameter), which is the common diameter of various pipes and pipe accessories. Pipes and pipe accessories with the same nominal diameter can be connected to each other and exchanged. It is not the actual outer diameter or inner diameter of the pipeline, although its value is close to or equal to the inner diameter of the pipeline.
In order to make the connection size of pipes and fittings consistent, the nominal diameter (also called nominal caliber and nominal diameter) is adopted. For example, welded steel pipes can be divided into thin-walled steel pipes, ordinary steel pipes and thickened steel pipes according to their thickness. Its nominal diameter is neither outer diameter nor inner diameter, but a nominal size similar to the inner diameter of ordinary steel pipe. Each nominal diameter corresponds to an outer diameter, and its inner diameter value varies with thickness. Nominal diameter can be expressed in metric millimeters or British inches. Pipe accessories are also expressed in nominal diameter, which has the same meaning as slotted pipes.
Calculation method of steel weight
The density of steel is 7.85g/cm3.
Theoretical weight calculation of steel
The unit of measurement for calculating the theoretical weight of steel is kilogram (kg). Its basic formula is:
W (weight, kg )=F (cross-sectional area mm2)×L (length, m)×ρ (density, g/cm3 )×11000 The theoretical weight calculation formula of various steels is as follows: Example of symbolic calculation of name (unit) calculation formula.
Round steel wire rod (kg/m) diameter w = 0.006165× d× d = mm.
For round steel with a diameter of 100 mm, find the weight per meter, and the weight per meter is = 0.006165×1002 = 61.65 kg steel bar (kg/m) w = 0.0061.
For steel bars with a cross-sectional diameter of 12 mm, find the weight per meter, which is 0.00617×122 = 0.89 kg square steel (kg/m).
W = 0.00785× a× a = side width mm.
For square steel with a side width of 20 mm, find the weight per meter, and the weight per meter is = 0.00785 ×202=3. 14kg flat steel.
(kg/m)
W= 0.00785 ×b ×d b= side width mm d= thickness mm.
For flat steel with a width of 40 mm and a thickness of 5 mm, find the weight per meter. Weight per meter = 0.00785× 40× 5 =1.57kg hexagonal steel (kg/m)
W = 0.006798× s× s = distance from the opposite side mm.
Find out the weight per meter of hexagonal angle steel with a distance of 50 mm across. Weight per meter = 0.006798× 502 =17kg octagonal steel (kg/m)
W = 0.0065× s× s = the distance from the opposite side is mm.
For octagonal steel with a margin of 80 mm, find the weight per meter, and the weight per meter = 0.0065 ×802=4 1.62kg equilateral angle steel (kg/m).
= 0.00785× [d (2b–d)+0.215 (R2–2R2)] b = lateral width d= lateral thickness.
R= radius of inner arc r= radius of end arc
Find the weight of 20 mm ×4mm equilateral angle steel per meter. According to the metallurgical product catalogue, the 4mm ×20 mm equilateral angle steel R is 3.5 and R is 1.2, so the weight per meter is = 0.00785× [4× (2× 20–4)+0.215× (3.52–2×/kloc-0.
W = 0.00785× [d (b+b–d)+0.215 (R2–2R2)] b = long side width b = short side width d= side thickness.
R= radius of inner arc r= radius of end arc
Find the weight per meter of 30 mm ×20mm ×4mm unequal angle steel. From the metallurgical product catalogue, it is found that the 30 ×20 ×4 unequal angle steel R is 3.5 and R is 1.2, so the weight per meter is = 0.00785× [4× (30+20–4)+0.215× (3.52–2×/kloc).
(kg/m)
W = 0.00785× [HD+2t (b–d)+0.349 (R2–R2)] h = height b= leg length d= waist thickness.
T= average fillet thickness R= inner arc radius r= end arc radius.
Find the weight per meter of 80 mm ×43mm ×5mm channel steel. From the metallurgical product catalog, the channel steel T is 8, R is 8 and R is 4, so the weight per meter is = 0.00785× [80× 5+2× 8× (43–5)+0.349× (82–42)] = 8.04 kg I-beam (kg/m).
W = 0.00785× [HD+2t (b–d)+0.615 (R2–R2)] h = height b= leg length d= waist thickness.
T= average fillet thickness R= inner arc radius r= end arc radius.
Find the weight of I-beam of 250 mm×118 mm× 10 mm per meter. From the metal material manual, I-beam t is 13, r is10, and r is 5, so the weight per meter is = 0.00785×.
D= thickness
For a steel plate with a thickness of 4 mm, calculate the weight per square meter. Weight per square meter =7.85 ×4=3 1.4kg steel pipe (including seamless steel pipe and welded steel pipe (kg/m))
W = 0.02466× s (d–s) d = external diameter S= wall thickness.
For seamless steel pipes with an outer diameter of 60mm and a wall thickness of 4mm, calculate the weight per meter ... Weight per meter = 0.02466× 4× (60–4) = 5.52kg.
What is a flange?
Flange is a disc-shaped part, which is the most common in pipeline engineering. Flanges are used in pairs. In pipeline engineering, flanges are mainly used for the connection of pipelines. In the pipeline to be connected, there are many ways to install flanges, such as threaded connecting flanges for low-pressure pipelines and welded flanges for pressures above 4 kg. Add a sealing point between the two flanges and fasten with bolts. The thickness of flanges with different pressures is different, and the bolts used are also different. When pumps and valves are connected to pipelines, the parts of these devices are also made into corresponding flange shapes, which is also called flange connection. All connecting parts that are bolted on the periphery of two planes and closed at the same time are generally called "flanges", such as the connection of ventilation pipes, which can be called "flange parts". But this connection is only a part of the equipment, such as the connection between the flange and the water pump, so it is not good to call the water pump a "flange part". Smaller ones, such as valves, can be called "flange parts" flanges.
Flange connection is an important connection mode in pipeline construction.
Flange connection refers to fixing two pipes, fittings or equipment on one flange respectively, adding a flange gasket between the two flanges, and completing the connection with bolts. Some pipe fittings and equipment have their own flanges, which are also flange connections.
Flanges are divided into threaded (threaded) flanges and welded flanges. Threaded connection flanges are used for small diameter low pressure, and welded flanges are used for large diameter high pressure and low pressure. Under different pressures, the thickness of flange and the diameter and number of connecting bolts are different.
According to different pressure grades, flange pads are made of different materials, ranging from low-pressure asbestos pads, high-pressure asbestos pads to metal pads.
Flange connection is easy to use and can withstand greater pressure.
Flange connection is widely used in industrial pipelines. At home, the pipe diameter is small and the pressure is low, so there is no flange connection. If you are in the boiler room or production site, there are flanged pipes and equipment everywhere.