Reducer is a chemical pipe fitting, also called large and small head. Its main function is to connect two pipe diameters of different sizes, and it can be divided into concentric reducer and eccentric reducer. The material of reducer can be divided into stainless steel reducer, carbon steel reducer and alloy steel reducer, and the steel used for reducer is # 20 steel or Q345 steel. Among the reducers, the eccentric reducer is mainly a kind of connecting pipe fitting used at the reducer of the pipe. The eccentric reducer generally adopts the forming process of shrinking and pressing, and can also be pressed by the process of reducing plus expanding and expanding, while for some special specifications of the reducer, the stamping forming method can also be used. In addition to using steel pipe as raw material to produce eccentric reducer, some special reducers can also be produced by stamping with steel plate, and the shape of the die used for drawing can be designed with reference to the internal surface size of the reducer.
The quality of the pipe eccentric reducer should be in line with the current national standards, eccentric reducer size allowable deviation should be the provisions of the standard. Eccentric reducer appearance should not have cracks, heavy skin, wall thickness should be greater than the wall thickness of the pipe section at the large diameter end, the roundness of the eccentric reducer should not be greater than 1% of the corresponding end outside diameter, and the allowable deviation of ± 3mm; concentric reducer centerline at both ends should coincide, and the allowable deviation of its eccentric value is ± 5 mm.
Pipe concentric reducer manufacturing process is simple, with a thicker wall thickness of the pipe as a blank, expand the caliber of one end or with a wall thickness of the pipe as a blank, reduce the caliber of one end can be. Regardless of the flare or shrinkage, it is generally pressed with a mold. At present, the domestic common use of eccentric mold pressed eccentric reducer by level, with this process to produce more than three levels of eccentric reducer, in the small head eccentric end will produce a serious gap, the inner wall tuberculosis, uneven wall thickness and oval and other phenomena. According to the oblique cut concentric reducer cut head structure instead of eccentric reducer, because the oblique section is not a round surface but an elliptical surface, there will be a wrong side between the end surface and the straight tube, can not be completely connected to the problem. If the new pressing process is adopted, that is, concentric reducers are first pressed with concentric molds, and then the pressed concentric reducers are put into eccentric molds to press the whole shape for the required eccentric reducers, the inner and outer surfaces are smooth, the small head is flat, the wall thickness is uniform, the roundness is qualified, and the raw materials used are less.
Structural and functional characteristics of reducers.
- ① Compared with the tee, the reducing elbow can not only change the pipeline direction, but also make the pipeline direction different angles, and the medium flow line in the pipe can be smooth, reducing the pressure drop and temperature drop;
- ② Compared with the equal elbow, the reduced-diameter elbow can not only absorb the displacement changes caused by the thermal expansion and contraction of the pipe, but also change the flow rate of the medium in the pipe;
- ③ Concentric reducer or eccentric reducer can make the medium flow rate in the pipe change and the flow line smooth without changing the pipeline direction;
- ④ The small end of the reducer can be added with a blind plate to form the head function.