What Are Pipe Fittings?

The role of the diameter pipe is to make the pipe diameter, from the fluid movement direction, most of them are from large to small, and some from small to large, such as the steam return water pipeline and the water pipeline, the diameter of the pipe is small to big. Reducer is commonly known as the size of the head.

  1. Malleable reducer
    Malleable reducer, generally divided into two, one is the internal thread reducer also known as external joints; The other is the combination of internal and external threads, called fill core, although it is not called reducer, but play the role of reducer.
  2. Steel reducers
    Steel reducer, divided into seamless and seamless two, seamless reducer with seamless steel pipe pressure, seamless pipe with steel plate cutting, rolled welded, also known as welded reducer. The two reducers are available in concentric and eccentric specifications. The bottom of the eccentric reducing diameter pipe is provided with a straight edge, which can make the pipe bottom into a horizontal plane when in use, and is convenient for discharging the materials in the pipe when stopping production and maintenance.
    The specification range of seamless reducer is DN25 ~ 600mm, and that of seam welded reducer is DN 200 ~ 1500mm.
    Steel reducers, as the finished pipe fittings on the pipeline, is only after the seventies began to have, the early process of pipe diameter change, mostly in the field production. The diameter of the pipe varies greatly. The pipe end is welded and processed directly into the diameter pipe. The diameter of the pipe changes little in the pipe end heating directly from falling. It is difficult to guarantee the welding quality of the reduced-diameter pipe because of much labor and much welding seam. At present, it is forbidden to use this method in the process pipeline with high welding quality.
    What is a pipe fitting? What are they?

It is necessary to change the direction, elevation or diameter of the pipe in the pipe system and draw out the branch pipe from the main pipe. Because of the different shapes of pipe system, the types of pipe fittings are more. Commonly used pipe elbow, tee, reducer, pipe joints, pipe caps and so on.

Elbow
The elbow is used to change the direction of the pipe. Commonly used elbow bending angle for 90 °, 45 ° and 180 °, 180 ° elbow also known as U-bend, there are special angle elbow, but a few.

  1. Malleable elbow
    Malleable iron elbow is the most common thread elbow. This kind of malleable steel pipe is mainly used for heating, water and gas pipes. In the process, in addition to the need to frequently disassembled low pressure piping, other material piping rarely used. The size of Ma steel elbow is relatively small, commonly used specifications range from 1 / 2 to 4 inches, according to its different surface treatment points galvanized and ungalvanized two kinds.
  2. Pressing elbow
    Pressed elbow, also known as stamping elbow or seamless elbow, is the use of high-quality carbon steel, stainless steel and low-alloy steel seamless pipe, etc., in a special mold pressing molding. The bending radius of the elbow is one and a half times the nominal diameter (R = 1.5DN). The elbow with bending radius equal to nominal diameter can also be used in special occasions (RR = 1DN.) Its specification range is within DN20 ~ 600mm. Its wall thickness range is consistent with the seamless steel pipe. Pressing elbow generally by professional manufacturers or processing plants with standard seamless steel pipe stamping process, leaving the factory elbow should be processed at both ends of the groove.
  3. Stamping and welding elbows
    The utility model relates to a stamping welding elbow, which adopts a sheet metal to be stamped into a half ring elbow by a die, and then two half ring elbows are assembled and welded. Its bending radius with seamless pipe elbow, specifications for the nominal diameter of 200mm or more.
  4. Welding elbows
    Welding elbow, also known as shrimp waist or shrimp body elbow. There are two production methods, one is in the processing plant with steel plate blanking, cutting, rolling and welding forming, most of the steel plate coil matching. The other is to use pipe material, the group of welding molding, its specifications generally more than 200mm. Use temperature can not exceed 200 °C, generally can be made in the construction site.
  5. High-pressure elbow
    High pressure elbow is forged from high quality carbon steel or low alloy steel. According to the form of pipe connection, the two ends of the elbow are processed into threads or bevels, and the precision of the processing is high. It is required that pipe thread and flange thread can be closely matched and freely screwed in without loosening. The pipe thread is suitable for petrochemical pipe with pressure 22.0 and 32.0 MPa. The common specification range is DN6 ~ 200mm.

Cross Tee
The tee is a pipe fitting connecting the main pipe and the branch pipe. It is divided into many kinds according to the different material and use. From the specification, can be divided into the same diameter tee and different diameter tee, with diameter tee is also called equal diameter tee; The same diameter tee refers to the diameter of the branch pipe and the pipe of the same; Diameter tee refers to the diameter of the branch pipe is less than the main pipe diameter, also known as unequal diameter tee, diameter tee amount to more.

  1. Malleable Cross Tee
    The manufacturing material and specification range of malleable cross tee are the same as the elbow. It is not used much in petrochemical process pipe, and is mainly used in indoor heating, water and gas pipe.
  2. Steel tee
    Before 1970s, the speed of industrial production technology development in China was relatively slow, and the engineering technology of process pipeline was relatively backward. In the design of various medium and low pressure steel pipes, when the pipe needs to use a three-way pipe, Generally use the method of digging hole to take over to solve, that is, in the need to connect the main branch pipe, according to the diameter of the branch pipe to dig a hole, and then the pipe welding. This method has many shortcomings, welding quality is not easy to ensure, welding pipe deformation, easy to enter impurities in the main. In the late 1970s, with the introduction of large modern production equipment such as metallurgy and petrochemical industry, Promote the development of process pipeline engineering technology, at present, China has been able to produce low-pressure pipeline steel stereotypes tee, has formed a series of products, seamless tee specifications for DN20 ~ 600mm, steel welded tee specifications DN150 ~ 1500mm.
    The forming tee is made of high quality pipe material, through cutting, digging, heating, drawing with mold, and then machining to become the forming product tee. The three links made of medium and low pressure steel are welded in the field. There are two kinds of tee, one is in the processing plant with steel plate material, after rolling welding; The other is an eye-opening takeover at the installation site.
  3. High-voltage tee
    High-pressure tee, there are two commonly used, one is welded high-pressure tee, a whole forging high-pressure tee.
    Welded high pressure tee, high quality high pressure steel pipe for material, manufacturing method is similar to digging pipe, the hole on the main pipe, to connect with the branch pipe diameter consistent. Welding quality is strict, usually require preheating before welding, heat treatment after welding. Its specification range is DN16 ~ 200mm, pressure 22 MPa, 32 MPa.
    The whole forging high pressure tee is usually connected with screw flange. Its specification range is SCH 160, DN 15 ~ 600mm, table number is added with “XXS,” its diameter range DN15 ~ 300mm.

Other pipe fittings

  1. Head
    The head is a plug used for sealing the end of a pipe. Commonly used head oval and cover two kinds.
    Oval head is also called pipe cap, its specification range is DN25 ~ 600mm, mostly used in low pressure pipeline. Flat cover head, according to its installation position is divided into two kinds, one is flat cover heads slightly larger than the outer diameter of the pipe, welded outside the pipe. The other is the flat cover head slightly less than the tube diameter, the head plate into the tube welding. Commonly used specifications for the range of DN15 ~ 200mm, this head for low pressure pipe.
  2. Boss
    Boss, also known as nozzle, is the automatic control instrument professional in the process of pipeline components, is installed by the process pipeline professional, so the boss is also classified as pipe fittings. Process pipeline with single-sided pipe joints also belong to this kind, are one end welded on the main pipe, the other end or installation of other components, or another to take over, the specification range for DN15 ~ 200mm, high, low pressure pipeline are used.
  3. Blinds
    This approach is prohibited for high process piping.
    (4) Other pipe fittings
  4. Head
    The head is a plug used for sealing the end of a pipe. Commonly used head oval and cover two kinds.
    Oval head is also called pipe cap, its specification range is DN25 ~ 600mm, mostly used in low pressure pipeline. Flat cover head, according to its installation position is divided into two kinds, one is flat cover heads slightly larger than the outer diameter of the pipe, welded outside the pipe. The other is the flat cover head slightly less than the tube diameter, the head plate into the tube welding. Commonly used specifications for the range of DN15 ~ 200mm, this head for low pressure pipe.
  5. Boss
    Boss, also known as nozzle, is the automatic control instrument professional in the process of pipeline components, is installed by the process pipeline professional, so the boss is also classified as pipe fittings. Process pipeline with single-sided pipe joints also belong to this kind, are one end welded on the main pipe, the other end or installation of other components, or another to take over, the specification range for DN15 ~ 200mm, high, low pressure pipeline are used.
  6. Blinds
    Blind plate, its role is to cut off the medium in the pipeline, according to the use of pressure and flange sealing surface in the form of the following:
    (1) The smooth surface blind plate, with the smooth sealing surface flange, its suitable pressure range is 1.0 ~ 2.5 MPa.
    (2) The convex blind plate has a convex surface on one side and a concave surface on the other side, which is used with the concave and convex sealing surface flange. The working pressure is 4.0 MPa, the specification range is DN25 ~ 400mm.
    (3) Trapezoidal groove blind plate, with trapezoid groove sealing face flange use, the use of pressure range of 6.4 ~ 16.0MPa. Specifications range from DN25 to 300mm.
    (4) “8” blind plate, also divided into smooth surface, concave and convex surface and trapezoidal groove surface three, The pressure is the same as the above three blind plates. The difference of the “8” blind plate is that it combines the two uses in one component, namely, the blind plate and the gasket are connected and fixed together. Flange pad into the blind plate, the outside of the gasket as a visual sign of whether the pipeline cut off.
    “8” word blind plate manufacturing materials have a variety of, according to the transmission medium temperature and pressure to choose. General low pressure pipeline, the temperature does not exceed 450 °C, the materials used are Q235A, 20 steel and 25 steel; At 450 ~ 550 °C, the materials used are 15CrMo and 1Cr5Mo. When the pressure is 4.0 ~ 16.0MPa, the temperature is greater than 550 °C, to use stainless steel.