Current standards GB/T10752-1995 Butt weld joints for marine steel pipes GB/T12772-1999 Flexible joint cast iron pipes and fittings for drainage GB/T 8803-2001 Hot oven test method for injection molded rigid polyvinyl chloride (PVC-U), chlorinated polyvinyl chloride (PVC-C), acrylonitrile-butadiene-styrene terpolymer (ABS) and acrylonitrile-styrene-acrylate terpolymer (ASA) pipe fittings GB/T 8802-2001 Determination of Vicat softening temperature of thermoplastic plastic pipes and fittings GB/T 18251-2000 Determination of pigment or carbon black dispersion in polyolefin pipes, fittings and mixed materials GB/T 18474-2001 Test method for crosslinking degree of crosslinked polyethylene (PE-X) pipes and fittings GB/T 18475-2001 Material classification and naming for thermoplastic pressure pipes and fittings General use (design) coefficient GB/T 18742.3-2002 Polypropylene piping systems for hot and cold water Part 3: Pipe fittings GB/T 18991-2003 Thermoplastic pipes and fittings for hot and cold water systems GB/T 18993.3-2003 Chlorinated polyvinyl chloride (PVC-C) piping systems for hot and cold water Part 3: Pipe fittings GB/T 18998.3-2003 Chlorinated polyvinyl chloride (PVC-C) piping systems for industrial use Part 3: Pipe fittings GB/T 19228.3-2003 Rubber O-rings for stainless steel compression fittings GB/T 19278-2003 General terms and definitions for thermoplastic pipes, fittings and valves GB/T 19473.3-2004 Polybutylene (PB) piping systems for hot and cold water Part 3: Pipe fittings GB/T 12459-2005 Steel butt-welded seamless pipe fittings GB/T 19712-2005 Plastic pipes and fittings Polyethylene (PE) saddle bypass impact test method GB 15558.2-2005 Buried polyethylene (PE) piping systems for gas Part 2: Pipe fittings GB/T 13663.2-2005 Polyethylene (PE) piping systems for water supply Part 2: Pipe fittings GB/T 19806-2005 Plastic pipes and fittings Polyethylene electrofusion assembly extrusion peel test GB/T 19807-2005 Plastic pipes and fittings Preparation of polyethylene pipe and electrofusion fittings combination test pieces GB/T 19808-2005 Tensile peel test of polyethylene electric fusion assemblies with a nominal outer diameter greater than or equal to 90 mm for plastic pipes and fittings GB/T 19809-2005 Preparation of hot-melt butt assemblies of polyethylene (PE) pipes/pipes or pipes/fittings for plastic pipes and fittings GB/T 19810-2005 Determination of tensile strength and failure mode of hot-melt butt joints of polyethylene (PE) pipes and fittings GB/T 13401-2005 Butt-welded fittings made of steel plate GB/T 19993-2005 Thermal cycle test method for combined systems of pipes and fittings for thermoplastic piping systems for hot and cold water GB/T 5836.2-2006 Rigid polyvinyl chloride (PVC-U) fittings for building drainage GB/T 15819-2006 Test method and technical requirements for environmental stress cracking sensitivity of polyethylene (PE) pipes for irrigation caused by inserted fittings GB/T 20201-2006 Mechanical connection fittings for polyethylene (PE) pressure pipes for irrigation GB/T 20207.2-2006 Acrylonitrile-butadiene-styrene (ABS) pressure piping systems Part 2: Fittings GB/T 20674.2-2006 Plastic pipes and fittings polyethylene system welding equipment Part 2: Electric fusion connection GB/T 20674.1-2006 Plastic pipes and fittings polyethylene system welding equipment Part 1: Butt fusion GB/T 8801-2007 Drop test method for rigid polyvinyl chloride (PVC-U) pipe fittings GB/T 21300-2007 Determination of opacity of plastic pipes and fittings GB/T 21409-2008 General rules for inspection, installation and use of glass equipment, pipelines and fittings GB/T 21408-2008 Glass equipment, pipelines and fittings. Versatility and interchangeability of 15mm to 150mm diameter pipelines and fittings GB/T 14383-2008 Forged socket welding and threaded fittings GB/T 13295-2008 Ductile iron pipes, fittings and accessories for water and gas pipelines GB/T 6567.3-2008 Graphical symbols for technical drawing pipeline systems GB/T 22051-2008 Sliding ferrule cold expansion fittings for cross-linked polyethylene (PE-X) pipes GB/T 6567.5-2008 Graphical symbols for technical drawing pipeline systems. Axonometric drawings of graphic symbols for pipelines, fittings and valves GB/T 11618.1-2008 Copper pipe joints Part 1: Brazed fittings GB/T 12772-2008 Flexible joint cast iron pipes, fittings and accessories for drainage GB/T 3420-2008 Grey cast iron fittings GB/T 11618.2-2008 Copper pipe joints Part 2: Press-fit fittings GB/T 23241-2009 Basic parameters and technical conditions of plastic pipes and fittings for irrigation GB/T 23682-2009 Requirements, design and installation of hose fittings, seismic isolation pipes and expansion joints for refrigeration systems and heat pumps GB/T 24452-2009 Chlorinated polyvinyl chloride (PVC-C) pipes and fittings for sewage and wastewater (high and low temperature) in buildings GB/T 17457-2009 Cement mortar lining of ductile iron pipes and fittings GB/T 24596-2009 Polyurethane coating of ductile iron pipes and fittings GB/T 24672-2009 Thin-walled metal pipes and fittings for sprinkler irrigation GB/T 5135.19-2010 Automatic sprinkler fire extinguishing system Part 19: Plastic pipes and fittings GB/T 26002-2010 Stainless steel corrugated hoses and fittings for gas transmission GB/T 26120-2010 Low-pressure stainless steel threaded fittings GB/T 26081-2010 Ductile iron pipes, fittings and accessories for sewage GB 26255.2-2010 Mechanical fittings for polyethylene piping systems for gas Part 2: Steel-plastic conversion fittings for pipes with a nominal outer diameter greater than 63mm GB 26255.1-2010 Mechanical fittings for polyethylene piping systems for gas Part 1: Steel-plastic conversion fittings for pipes with a nominal outer diameter not greater than 63mm GB/T 26500-2011 General technical requirements for fluoroplastic lined steel pipes and fittings GB/T 19228.2-2011 Stainless steel press fittings Part 2: Thin-walled stainless steel pipes for connection GB/T 19228.1-2011 Stainless steel press fittings Part 1: Press fittings GB/T 27684-2011 Titanium and titanium alloy seamless and welded pipe fittings GB/T 27891-2011 Carbon steel press fittings Industry standards 1) "Steel butt-weld seamless pipe fittings" GB/T 12459-2005 2) "Steel plate butt-weld pipe fittings" GB/T 13401-2005 3) "Power station steel butt-weld pipe fittings" DL/T 695-1999 SH 3408 Steel butt-weld seamless pipe fittings SH 3409 Steel plate butt-weld fittings SH 3410 forged steel socket-weld fittings HGJ514-87 seamless butt-weld fittings of carbon steel and low alloy steel American pipe fittings standards ASME/ANSI B16.9 seamless steel pipe butt-weld fittings manufactured in factories ASME/ANSI B16.11 socket-weld and threaded forged fittings ASME/ANSI B16.28 steel butt-weld small radius elbows and setbacks ASME B16.5 pipe flanges and flange accessories MSS SP-43 forged stainless steel butt-weld fittings MSS SP-83 socket-weld and threaded unions MSS SP-97 integrally reinforced sockets with socket-weld, threaded and butt-weld ends ASME B16.3-1998 forged cast iron threaded pipes Pipeline standards 1 Former Ministry of Labor Document [1996] No. 140 Regulations on Safety Management and Supervision of Pressure Pipelines * 2 National Quality Inspection and Inspection Bureau Document [2002] No. 235 Qualification Permit and Management Rules for Pressure Vessel and Pressure Pipeline Design Units 3 Bureau of Quality and Technical Supervision Document [1999] No. 143 Notice on Strengthening Safety Supervision and Management of Liquefied Petroleum Gas Stations 4 Bureau of Quality and Technical Supervision Document [1999] No. 59 Opinions on Implementing the "Notice on Strengthening Safety Supervision and Management of Liquefied Petroleum Gas Stations" 5 Former Ministry of Labor Document [1996] No. 276 Regulations on Safety Technical Supervision of Steam Boilers * 6 Former Ministry of Labor Document [1997] No. 74 Regulations on Safety Technical Supervision of Hot Water Boilers * 7 Former Ministry of Labor Document [1993] No. 356 Regulations on Safety Technical Supervision of Organic Heat Carrier Boilers * 8 Bureau of Quality and Technical Supervision Document [1999] No. 154 Regulations on Safety Technical Supervision of Pressure Vessels * 9 GB4962-1985 Safety technical regulations for the use of hydrogen 10 GB6222-1986 Safety regulations for industrial gas 11 GB11984-1989 Safety regulations for chlorine 12 GB13348-1992 Safety regulations for static electricity of liquid petroleum products 13 SY6186-1996 Safety regulations for petroleum and natural gas pipelines 14 SY5737-1995 Safety regulations for oil pipeline transportation 15 DL/T561-95 Guidelines for water vapor chemistry supervision in thermal power plants 16 DL/T709-1999 Technical regulations for safety inspection of pressure steel pipes Fire protection, sanitation and environmental protection 1 GB50160-92 (Partially revised in 1999) Fire protection design specifications for petrochemical enterprises * 2 GB5044-1985 Occupational contact toxic hazard level classification * 3 GBJ16-87 (Partially revised in 2001) Code for fire protection of building design 4 GBJ73-84 Code for design of clean workshops 5 GB/T3840-1991 Technical principles and methods for formulating local air pollutant emission standards GB16297-1996 Comprehensive emission standards for air pollutants 6 GB50058-1992 Design specification for electrical installations in explosive and fire hazardous environments * GB50084-2001 Design specification for automatic sprinkler fire extinguishing systems 7 GB50183-1993 Fire protection code for crude oil and natural gas engineering design 8 GB50187-1993 General lay...
In the history of the development of building water supply pipelines in my country, it has experienced an evolution process from galvanized steel pipes to plastic pipes (PP-R) to composite pipes to copper pipes and stainless steel pipes. Among them, galvanized steel pipes have long occupied a dominant position before 2000. Because galvanized steel pipes are not corrosion-resistant, they rust after long-term use, which leads to secondary pollution of water quality, yellow water, pipe scaling, bacterial growth and other problems, which seriously affect people's health. Moreover, due to the influence of rust, the service life of galvanized steel pipes is generally only 8-12 years, and the problem of water leakage and maintenance during use is even worse. Due to the great economic differences between domestic regions, galvanized steel pipes still occupy a certain market in backward areas. PP-R pipes have the advantages of corrosion resistance, environmental protection and long service life compared to galvanized steel pipes, so they have developed rapidly for some time. However, the unavoidable shortcomings of plastic pipes themselves are also exposed during use. The main problems are severe deformation due to heat and cold cracking. Aging is accelerated by sunlight or hot and cold changes, and it is easy to burn. Due to the insufficient standardization of the market development in my country, the investment threshold of plastic pipe manufacturers ranges from hundreds of thousands to hundreds of millions of yuan, and manufacturers are rampant and disorderly competition is serious. In order to reduce production costs and seize the market, small enterprises cut corners in the production process, and low-priced and low-quality products flood the market. Affected by this, the further promotion of PP-R pipes has been greatly restricted. After four years of development, there are now several large enterprises with over 100 million yuan of investment to survive and develop. Composite pipes are a transitional product on the historical stage of pipelines. The so-called composite pipe is a composite of metal and plastic, with two types of inner plastic coating and outer plastic coating, and the two materials are glued together. Due to the different properties of the two materials, the linear expansion coefficient of plastic is more than 4 times that of metal. Therefore, due to temperature changes in use, plastic and metal debonding and stratification, dislocation of joints and other problems occur, resulting in large-scale water leakage in the pipeline. This has occurred in a large number of domestic engineering examples. As a high-end new type of pipe, copper pipes are highly respected by the industry. The main advantages of copper pipes are durability and good hygienic properties, especially the copper ions that are free in the pipe water have a certain bactericidal effect. However, copper pipes have not been widely promoted and used in the market. The reasons are mainly the following: First, the cost is high. Copper is a limited resource. Under the current national conditions, the high price limits its scope of use; second, there is controversy over the quality of domestic copper, and copper pipes often have verdigris (oxidation and rust) during use; third, the construction is difficult. Copper pipes are connected by welding, which requires relatively high welding technology. In summary, in my country's building water supply pipeline system, the four major problems recognized by the industry - pipeline leakage, secondary water pollution, short life of water pipes, and troublesome pipeline construction - have not been effectively solved. However, with the rapid development of the national economy, the improvement of people's living standards and the grade of buildings, there is an increasing need for a new type of water supply pipeline that is environmentally friendly, hygienic, safe and leak-proof, economical and durable, and easy to construct. Under such historical conditions, thin-walled stainless steel pipes have entered the historical stage of the pipeline revolution as an emerging water supply pipe material. Stainless steel materials are environmentally friendly, corrosion-resistant, durable, have smooth inner walls, low water flow loss, are luxurious and beautiful after polishing, and have a cost-effectiveness that exceeds any existing water supply materials. Once they were released, they were widely valued by the industry. 1. Large demand for building water supply pipelines Due to the differences in economic conditions and building requirements in various regions of the country, all kinds of pipelines have a certain market, but from the application situation in developed regions, the use share of thin-walled stainless steel pipes is gradually expanding. With the improvement of the economic level of underdeveloped regions, it will also be developed and applied to a certain extent. 2. Pipeline direct drinking water is developing rapidly. The direct drinking water industry has gradually developed in China, but due to different regional economic levels, it has developed rapidly in developed cities and slowly in underdeveloped regions. In June 2005, the Ministry of Construction promulgated the new "Urban Water Quality Standards", which proposed higher drinking water indicators. In August 2006, the industry standard "Technical Regulations for Pipeline Direct Drinking Water Systems" (CJJ 110-2006) came into effect. The implementation of these two standards has greatly promoted the large-scale development of the direct drinking water industry. By 2007, the direct drinking water industry has grown into a market with an annual output value of nearly 10 billion yuan. The penetration rate of direct drinking water in developed regions such as Beijing, Shanghai, and Guangzhou has reached 10%, and medium-sized cities are also actively implementing or planning. It is estimated that the capacity of the entire domestic direct drinking water market is 100 billion yuan. According to the proportion of direct drinking water pipes accounting for 15% of the entire direct drinking water market and thin-walled stainless steel accounting for 65% of the direct drinking water pipe market, there is a market of about 10 billion yuan. In the direct drinking water delivery pipeline, thin-walled stainless steel pipes are undoubtedly the best with their excellent performance of hygiene, beauty, high strength and high cost performance. 3. Domestic substitution for imports has a bright future. The promotion and application of domestic thin-walled stainless steel pipes is showing a trend of replacing imported pipes. At present, the production and use of domestic thin-walled stainless steel pipes and pipe fittings are gradually increasing, and the production technology has also been improved to a certain extent. Localization reduces the cost of use and promotes the improvement of technical capabilities, making thin-walled stainless steel pipes acceptable to national conditions. Replacing imported pipes is an inevitable development and has a very bright future.
There are various ways to connect stainless steel pipes. The common key types include compression, union, compression, push-on, taper thread, socket welding, union flange connection, welding, and a series of connection methods that combine welding and traditional connection. These connection methods have different application scopes according to their principles, but most of them are easy to install, firm and reliable. The sealing valve or gasket material used in the connection is mostly made of silicone rubber, nitrile rubber and EPDM rubber that meet national standards, eliminating the user's worries. Here are some common ones for a brief introduction: 1. Compression connection Compression connection: insert the pipe into the pipe mouth of the pipe fitting, tighten it with a nut, and use the spiral force to compress the sleeve of the pipe mouth through the sealing ring to seal and complete the connection of the pipe. Features: From the perspective of connection alone, the pipe wall can be relatively thin, save materials, easy to install, can be disassembled, easy to repair, and the tool has a large pulling force. Scope of application: DN50 or less, can be exposed. Note: Compression connection requires flanging the pipe end of the pipe, or using a groove tool to spin a convex groove on the pipe end of the pipe, or adding a C-type thrust ring to the groove on the pipe end. The workload of on-site processing is large and the quality cannot be guaranteed. 2. Compression connection Compression connection: A special rubber sealing ring is installed in the U-shaped groove at the end of the compression pipe fitting. During installation, the stainless steel pipe is inserted into the socket pipe fitting to the positioning step position, and the U-shaped groove and the compression part on one or both sides of the U-shaped groove are squeezed simultaneously with a special compression tool. The rubber sealing ring plays a sealing role after being squeezed, and the pipe fittings and pipes at the compression part shrink and deform at the same time (the cross section forms a hexagonal shape) to play a positioning and fixing role, thereby effectively realizing the connection of stainless steel pipes. Features: Easy and quick installation, reliable sealing, but cannot be disassembled. Scope of application: DN100 or less, can be installed openly or buried. Description: The construction site of the compression connection requires little work, and only requires pipe cutting, deburring, pipe positioning, and compression. No other processing is required for the connecting pipes, avoiding quality defects caused by human factors. 3. Flexible connection Flexible connection: insert the pipe into the pipe mouth of the pipe fitting, tighten the cap nut with a special wrench, and seal the sealing ring with a clamping ring to complete the connection between the pipe and the pipe fitting. Features: easy installation, disassembly, and adaptable to harsh environments such as foundation sinking. Scope of application: DN60 or less, indoor open installation, underground buried pipes, earthquakes, ground subsidence, and heavy vehicles passing through the environment. Description: A groove machine is required to roll a groove on the end of the pipe on site to fix the C-ring. 4. Welding connection Welding connection: Process the groove at the end of the pipe, and use manual or automatic welding to make a ring welding on the pipe. Features: Traditional connection method, high welding strength, but welding conditions are required on site. Scope of application: Both large and small pipe diameters are available, and can be exposed or buried. Note: The wall thickness of the pipe is required to be thicker, and on-site welding has high technical requirements for the installer. It is impossible to perform solid solution treatment, and the welding quality cannot be fully guaranteed. 5. Socket welding connection Socket welding connection: Insert the pipe into the socket pipe fitting, and the pipe fitting and the pipe are sealed by annular argon arc welding to complete the pipe connection. Features: Traditional connection method, high strength, less leakage in the pipe network. Scope of application: Both large and small pipe diameters are available, and can be exposed or buried. Note: On-site welding cannot be performed for solid solution heat treatment, and the corrosion resistance of the weld is reduced. It is basically the same as carbon steel, and intergranular corrosion and stress corrosion will occur, affecting the service life of the stainless steel pipeline system. 6. Flange connection Flange connection: The flange and the pipe are annularly welded, and fastened with quick clamps or bolts to make the sealing gasket between the flanges seal and complete the pipe connection. Features: Traditional connection method, safe and reliable. Scope of application: DN125-200, public buildings or large buildings pipelines. Description: The traditional flange welding method can also be transformed to make the flange into a flexible flange, the pipe port is flanged or welded, the ring mouth is embedded in the groove, and the rubber seal is placed in the groove, and the sealing element is protected by limited compression. 7. Cone thread connection Cone thread connection: The external thread and the pipe are annularly welded with argon arc welding, and the internal thread pipe fittings are connected with cone threads to seal and complete the pipe connection. Features: Traditional connection method, simple, and strong pulling force. Scope of application: DN65-100, public buildings and large buildings pipelines, adapt to harsh environments such as foundation sinking, and are more suitable for high temperature and high pressure projects. Description: Welding is required on site, the external thread may be welded obliquely, the welding quality cannot be guaranteed, and rework or sealing failure may occur. There is also a problem of reduced corrosion resistance at the weld.
Stainless steel is widely used in our production and life. Its own characteristics determine that it has irreplaceable functionality in many fields, and its use method is simple, the manufacturing cost is not expensive, and it is scalable. The use of stainless steel in the food industry is also universal. Among them, stainless steel sealed barrels can be seen in many occasions. It not only bears the role of storing food and related food processing materials, but also has the characteristics of protecting the nature of food. The most important feature of stainless steel is that it is stable in nature and will not rust due to harsh environment or high humidity. In this way, this material will be used for food storage in some food processing workshops. Rustproof can not only ensure the beauty of its own structure and appearance, but also will not contaminate food and affect the nature of food. This is also the reason why many canteens use stainless steel sealed barrels when serving meals, lobby or making some unique food. Secondly, stainless steel is very easy to clean. Sealed barrels also include different materials such as plastic barrels and stainless steel. Compared with plastic barrels, stainless steel is not easy to scratch, and will not leave stubborn stains inside and outside the barrel, so it is very easy to clean. For the food processing industry, the number of such barrels used is very large. Generally speaking, it saves a lot of cleaning labor and also reduces the barrel elimination rate. In addition, stainless steel sealed barrels are strong enough. In the food industry, long-distance transportation services are often required, and the food status is also different. To ensure the integrity of the food, it is usually necessary to have the characteristics of being difficult to damage and good sealing.
Introduction to stainless steel All metals react with oxygen in the atmosphere to form an oxide film on the surface. Unfortunately, the iron oxide formed on ordinary carbon steel continues to oxidize, causing the rust to expand and eventually form holes. The surface of carbon steel can be protected by paint or oxidation-resistant metals (such as zinc, nickel and chromium) for electroplating, but, as people know, this protection is only a film. If the protective layer is damaged, the steel below will begin to rust. Steel that is resistant to weak corrosive media such as air, steam, and water, and chemically corrosive media such as acids, alkalis, and salts. Also known as stainless acid-resistant steel. In practical applications, steel that is resistant to weak corrosive media is often called stainless steel, while steel that is resistant to chemical media is called acid-resistant steel. Due to the difference in chemical composition between the two, the former is not necessarily resistant to chemical media, while the latter is generally rust-resistant. The corrosion resistance of stainless steel depends on the alloying elements contained in the steel. Chromium is the basic element that makes stainless steel corrosion-resistant. When the chromium content in steel reaches about 12%, chromium reacts with oxygen in the corrosive medium to form a very thin oxide film (self-passivation film) on the steel surface, which can prevent further corrosion of the steel matrix. In addition to chromium, commonly used alloying elements include nickel, molybdenum, titanium, niobium, copper, nitrogen, etc., to meet the requirements of stainless steel organization and performance for various uses. Definition of stainless steel A high-alloy steel that can resist corrosion in air or chemical corrosive media. Stainless steel has a beautiful surface and good corrosion resistance. It does not need to undergo surface treatment such as plating, but exerts the inherent surface properties of stainless steel. It is a kind of steel used in many aspects and is usually called stainless steel. Representative performance includes 13-chromium steel, 18-chromium-nickel steel and other high-alloy steels. From the perspective of metallography, because stainless steel contains chromium, a very thin chromium film is formed on the surface. This film isolates the oxygen that invades the steel and plays a role in corrosion resistance. In order to maintain the inherent corrosion resistance of stainless steel, the steel must contain more than 12% chromium. Types of stainless steel Stainless steel can be roughly classified according to its use, chemical composition and metallographic structure. Austenitic steel is basically composed of 18% chromium and 8% nickel. The amount of each element added varies, and steels for various purposes are developed. 1. Classification by chemical composition: ①CR series: ferrite series, martensite series; ②CR-NI series: austenite series, abnormal series, precipitation hardening series. 2. Classification by metallographic structure: ①Austenitic stainless steel; ②Ferritic stainless steel; ③Martensitic stainless steel; ④Duplex stainless steel; ⑤Precipitation hardening stainless steel. 3. Surface categories of stainless steel The development of stainless steel has made the corrosion resistance, appearance, processability, strength and other characteristics of stainless steel far exceed other materials. Moreover, many surface treatment methods of stainless steel can achieve rich colors and shapes, which has made a great contribution to the development of stainless steel.
Grooved fittings are a new type of steel pipe connection fittings, also called clamp connections, which have many advantages. Overview of Grooved Fittings The design specifications for automatic sprinkler fire extinguishing systems state that the connection of system pipes should be made with grooved fittings or threaded or flanged connections; pipes with a diameter equal to or greater than 100 mm in the system should be connected in sections with flanges or grooved fittings. Grooved fitting connection technology, also known as clamp connection technology, has become the first choice for current liquid and gas pipeline connections. Although this technology was developed later in China than abroad, it was quickly accepted by the domestic market due to its advanced technology. Since 1998, it has been developed and applied in just a few years, and has gradually replaced the two traditional pipeline connection methods of flanges and welding. Not only is it more mature in technology, it is also generally recognized by the market, and has been actively guided by national laws and regulations. The application of grooved fitting connection technology makes the complex pipeline connection process simple, fast and convenient. It has taken a big step forward in pipeline connection technology. Introduction to pipe fittings Grooved pipe fittings include two major categories of products: ① Pipe fittings that play a connecting and sealing role include rigid joints, flexible joints, mechanical tees and grooved flanges; ② Pipe fittings that play a connecting and transitioning role include elbows, tees, crosses, reducers, blind plates, etc. Grooved connection pipe fittings that play a connecting and sealing role mainly consist of three parts: sealing rubber rings, clamps and locking bolts. The inner rubber sealing ring is placed on the outside of the connected pipe and matches the pre-rolled groove. Then the clamp is buckled on the outside of the rubber ring and then fastened with two bolts. Because the rubber sealing ring and clamp adopt a unique sealable structural design, the groove connector has good sealing performance, and its sealing performance increases accordingly with the increase of the fluid pressure in the pipe.
The meaning and difference of pipe diameters Dn, De, D, d, and Φ DN refers to the nominal diameter of the pipe Note: This is neither the outer diameter nor the inner diameter; it should be related to the early development of pipeline engineering and the imperial units; it is usually used to describe galvanized steel pipes, and its corresponding relationship with the imperial units is as follows: 4-inch pipe: 4/8 inch: DN15; 6-inch pipe: 6/8 inch: DN20; 1-inch pipe: 1 inch: DN25; 2-inch pipe: 1 and 1/4 inch: DN32; 1/2-inch pipe: 1 and 1/2 inch: DN40; 2-inch pipe: 2 inch: DN50; 3-inch pipe: 3 inch: DN80 (also marked as DN75 in many places); 4-inch pipe: 4 inch: DN100; De mainly refers to the outer diameter of the pipe Generally, those marked with De need to be marked in the form of outer diameter x wall thickness; Mainly used to describe: seamless steel pipes, plastic pipes such as PVC, and other pipes that require clear wall thickness. Take galvanized welded steel pipe as an example, the two marking methods of DN and De are as follows: DN20 De25×2.5mm DN25 De32×3mm DN32 De40×4mm DN40 De50×4mm And so on... We are used to using DN to mark welded steel pipes, and rarely use De to mark pipes without involving wall thickness; But marking plastic pipes is another matter; it is still related to industry habits. In the actual construction process, the pipes we simply call 20, 25, 32, etc. all refer to De, not DN, which is a difference in specifications. If you don't understand it, it is easy to cause losses during procurement and construction. The connection methods of the two pipe materials are nothing more than: threaded connection and flange connection. Other connection methods are rarely used. Galvanized steel pipes and PPR pipes can use the above two connections, but it is more convenient to use threads for pipes less than 50, and it is more reliable to use flanges for pipes greater than 50. Note: If two metal pipes of different materials are connected, it is necessary to consider whether a galvanic reaction will occur, otherwise it will accelerate the corrosion rate of the active metal material pipe. It is best to use flange connection and use insulating materials such as rubber gaskets to separate the two metals, including bolts, to avoid contact. The respective ranges of De, DN, d, and ф! De-- Outer diameter of PPR, PE pipe, polypropylene pipe DN-- Nominal diameter of polyethylene (PVC) pipe, cast iron pipe, steel-plastic composite pipe, galvanized steel pipe d-- Nominal diameter of concrete pipe ф-- Nominal diameter of seamless steel pipe, its specifications are, such as ф100:108 × 4 DN15-ф22mm, DN20-ф27mm, DN25-ф34mm, DN32-ф42mm, DN40-ф48mm, DN50-ф60mm, DN65-ф76(73)mm, DN80-ф89mm, DN100-ф114mm, DN125-ф140mm, DN150-ф168mm, DN200-ф219mm , DN250-ф273mm, DN300-ф324mm, DN350-ф360mm, DN400-ф406mm, DN450-ф457mm, DN500-ф508mm, DN600-ф610mm, DN15-ф18mm, DN20-ф25mm, DN25-ф32mm, DN32-ф38mm, DN40-ф45mm, DN50-ф57mm, DN65-ф73mm, DN80-ф89mm, DN100-ф108mm, DN125-ф133mm, DN150-ф159mm, DN200-ф219mm ,DN250-ф273mm, DN300-ф325mm, DN350-ф377mm, DN400-ф426mm, DN450-ф480mm, DN500-ф530mm, DN600-ф630mm.
Stainless steel pipe fittings are a type of pipe fittings. They are made of stainless steel, so they are called stainless steel pipe fittings. They include: stainless steel elbows, stainless steel tees, stainless steel crosses, stainless steel reducers, stainless steel pipe caps, etc. According to the connection method, they can be divided into four categories: socket-type stainless steel pipe fittings, threaded stainless steel pipe fittings, flange stainless steel pipe fittings and welded stainless steel pipe fittings. Stainless steel elbows are used for pipe turns; flanges are used to connect pipes to each other, connected to the pipe ends, stainless steel tees are used for the places where three pipes converge; stainless steel crosses are used for the places where four pipes converge; stainless steel reducers are used for the places where two pipes of different diameters are connected. Main stainless steel materials: 304, 304L, 316|, 316L. Stainless steel pipe fittings are a general term for various stainless steel pipe connection workpieces, which can be divided into different categories according to shape, purpose, connection method, etc. It has the characteristics of easy installation, high performance, durability, etc., and is widely used in various pipeline construction and installation. Iron and steel are distinguished by the amount of carbon content. Iron-carbon alloys with a carbon content of less than 2% are called steel, and those with a carbon content of more than 2% are called iron. Steel is widely used because it is tough, elastic and rigid. Everything we come into contact with in life is steel, but people call it differently. For stainless steel, whether it can be attracted by a magnet or not, as long as it meets its quality standards, it is stainless steel. Specifications Ф3.0mm～450.0mm, there are stainless steel thin tubes, square tubes, thick-walled tubes, seamless tubes, seamed tubes, industrial tubes, liquid delivery tubes, with bright and matte surfaces that can be customized according to customer requirements. Materials: SUS310S, SUS316, 316L, 304, 304L, 321, 303, 303CU, 301, 202, 201, etc.
In the piping system, elbows are pipe fittings that change the direction of the pipe. According to the angle, there are three most commonly used elbows: 45°, 90°, and 180°. In addition, according to the needs of the project, there are other non-normal angle elbows such as 60°. The materials of elbows include cast iron, stainless steel, alloy steel, forgeable cast iron, carbon steel, non-ferrous metals and plastics. The ways to connect with the pipe are: direct welding (the most common way) flange connection, hot melt connection, electric fusion connection, threaded connection and socket connection. According to the production process, it can be divided into: welded elbow, stamped elbow, push elbow, cast elbow, butt welding elbow, etc. Other names: 90 degree elbow, right angle elbow, love elbow, etc. Elbow is a commonly used connecting pipe fitting in plumbing installation, used for connection at the bend of the pipe to change the direction of the pipe. Other names: 90° elbow, right angle elbow, love elbow, stamped elbow, pressed elbow, machine elbow, welded elbow, etc. Uses: A commonly used connecting pipe fitting in pipeline installation, connecting two pipes with the same or different nominal diameters, so that the pipeline can be turned at 90°, 45°, 180° and various degrees, with a nominal pressure of 1-1.6Mpa. The bending radius is less than or equal to 1.5 times the pipe diameter and is an elbow, while the bending radius is greater than 1.5 times the pipe diameter and is a pipe bend.
Tees are pipe fittings and pipe connectors used at the branch pipes of the main pipeline. Equal diameter tees are a type of tees. The diameters of the three pipes of equal diameter tees are equal. Equal diameter tees are widely used in the construction and maintenance of projects in industries such as petrochemicals, oil and gas, liquefied gas, fertilizers, power plants, nuclear power, shipbuilding, papermaking, pharmaceuticals, food hygiene, and urban construction. The pressure requirements for this type of pipe fitting in industry are relatively high, and the maximum pressure can reach 600 kilograms. The water pipe pressure in life is relatively low, generally 16 kilograms. The expression method is as follows: For equal diameter tees, for example, "T3" tee means an equal diameter tee with an outer diameter of 3 inches. For reducing tees, for example, "T4×4×3.5" means a reducing tee with the same diameter of four inches and a reducing diameter of 3.5 inches.
Reducers are also called reducers, reducers, and reducer straights. One of the chemical pipe fittings, used to connect two pipes of different diameters. According to the different shapes, they can be divided into concentric reducers and eccentric reducers. The reducers are made of stainless steel reducers, alloy steel, and carbon steel reducers. The reducers are made of 20# steel, Q235, Q345, 16Mn, etc. The main connection methods of reducers in stainless steel pipe fittings are: threaded, clamp, welding, etc. Various American standard and national standard stainless steel reducers can be produced according to customer needs. Please call for consultation.
1. Grooved flanges are generally used in fire protection and water supply pipes. Grooved flange: refers to a flange with a groove connected to the flange end face. 2. High-neck flanges are generally used in chemical pipelines with high temperature, high pressure, flammable and explosive, highly toxic, and high requirements for internal cleanliness of the pipeline. High-neck flange: The neck height is higher, which improves the rigidity and bearing capacity of the flange. Compared with butt-welded flanges, the welding workload is large, the consumption of welding rods is high, and it cannot withstand high temperature, high pressure, repeated bending and temperature fluctuations, but it is more convenient to install on site, and the process of filming and flaw detection of welds can be omitted, which is more popular.
